Progress 07/01/10 to 06/30/15
Outputs
Target Audience:Scientists, students and commercial growers. Progress was shared in professional meetings (3 international meetings, and 2 national meetings), in grower meetings (10 within the state), and in undergraduate and graduate classes. Specific groups were: The international Society for Horticultural Science, The American Society for Horticultural Science, International meeting on Plant Dormancy held in Aukland New Zealand in November 2013, the Great Lakes Ag Expo (December 2010, 11, 12, 13, 14) and the NW Michigan Fram and Orchard show (Jan. 2010, 11, 12, 13, 14). It was also featured in report on NPR Morning addition (May 2015) Changes/Problems:The emphasis in this project changed from carbon assimilation and storage, to more work on how the changing environment effects development and how it might be mitigated, based on sound physiological principals. What opportunities for training and professional development has the project provided?The training of graduate and undergraduate students, and the education of growers and extension educators through educational sessions, and on farm demonstrations. How have the results been disseminated to communities of interest?Results have been disseminated through grower meetings, through public radio, and news articles. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The studies in this project helped to establish biotic and abiotic thresholds based on carbon assimilaion and storage for apple and cherry growers in Michigan. It also helped to define how the amount of foliage per tree times its duration effects the trees ability to with stand winter cold injury. Environmental stress has also been the focus of the project in the last couple of years because of the warming climate trends in the great lakes. Some specific accomplishments are: 1. We developed a method to predict when sweet cherries could be mechanically harvested with stems on based on fruit weight. 2. We devised a method to delay bloom and thus decrease possible injury due to spring frost during bloom by evaporative cooling buds with a fine mist of water for both apple and cherry up to 14 days. 3. We developed a realistic carbon footprint for both apple and tart cherry orchards based on accumulation of carbon extimated from the cross sectional area of the trunk of the tree.
Publications
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Progress 10/01/13 to 09/30/14
Outputs
Target Audience: Scientists, students and commercial growers. Progress was shared during a graduate student seminar course on climate change (Winter and spring of 2014), with Michigan Cherry Research Committee, the Michigan Apple Research Committee, and the Michigan State Horticultural Society. A posters were presented to collegues at the Interational Meeting on Plant Dormancy held in Aukland New Zealand in November of 2013, and the American Society for Horticultural Science meetings in Orlando Florida in July 2014. Demonstration plots on mist-cooling to delay bud break were set on growers farms in Southwest Michigan, Central Michigan (Charlotte) and NWest Michigan (Elk Rapids) on apple, sour cherry, sweet cherry, and apricot. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Opportunities to train graduate students and post-docs to be able to use new tools designed to investigate carbon assimilation and partitioning. How have the results been disseminated to communities of interest? Results concerning the mist-cooling have been discussed at grower meeting, in classes, and by on farm demonstrations. What do you plan to do during the next reporting period to accomplish the goals? Contnue to refine the application methodes for mist-cooling, and to use 13C as a tool to investigate the effect of abiotic stress on carbon assimilation and partitioning in perennial crops
Impacts
What was accomplished under these goals?
Environmental stress has been the focus of the project in the last couple of years with emphasis on early bloom, and water stress. Because Michigan's apple and cherry peroduction was significantly reduced in 2012 because buds developed to early in the spring and then were killed by freezing conditions normal for spring in Michigan, we reinvistagated the potential for mist-cooling as a method to delay bud break in fruit crops. Once endodormancy has been fufilled, bud development is based on heat accumulated by individual buds. Evaporative cooling was shown to delay bloom up to 3 weeks using inpact sprinklers that applied up to 36 acre inches of water in a 30 day period. Although bloom was delayed, fruit set was decreased, and diseases were increased. That coupled with the large use of water, resulted in limited use of this techniques. This study re-examines the use of evaporative cooling by using new technologies by bringing together three new technologies for the application of water mist via a new pesticide appications system, the solid set canopy application system (SSCD). In 2013 and again with expanded trials in 2014, we were able to delay bloom in sweet cherries, apples (3 varieties) and apricot up 11 days with no decrease in fruit set, no increased disease, and no significant effect on harvest quality. The system used significantly less water during the cooling period by timing application based on temperature, humidity and wind speed. Water Stress in 'Budagovski 9 roostock seedlings. Budagovsiki 9 ('Bud 9") is one of the most important roostocks used in high density plantings under Michigan conditions. Compared to well-watered control trees, trees grown in moderately limited soil water fixed a lower amount of photosynthate fixed by leaves, but no major difference in partitioning. Root respiration was reduced by water limitation, and was linearly related to the amount of excess Carbon allocated into the roots. We concluded that under moderate stress although growth was limited, there was no significant difference in carbon allocation.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Rijal, I., J. Flore, and J. Andresen. 2014 'Mist-cooling to delay
bloom and prevent frost damage- old idea, new technology' in American
Society for Horticultural Science (ASHS) annual meeting, July 28-31,
2014, Orlando, FL.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
M.Toselli, G.Moncolini, J.A.Flore and L.Lombardini. 2014. Leaf assimilation, carbon translocation and root respiration in 'Budagovski 9' apple cuttings grown in low soil moisture condition. Europ. J. Hort. Sci 79(5). 241-247.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
N.S. Jaikumar, S.S. Snapp, J.A. Flore and W.Loescher. 2013. Photosynthetic responses in annual rye, perennial wheat, and perennial rye subjected to modest source:sink ratio changes. Crop Science 04.0280
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
J.Flore, G. Lang, and I.Rijal. 2013. Mist-cooling to delay bloom and prevent frost, old idea new technology. Poster 5th International conference on plant dormancy, August 4-7, 2013. Aukland NZ
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Progress 01/01/13 to 09/30/13
Outputs
Target Audience: Plant science professionals interested in carbon physiology, with emphasis on biotic or abiotic stress. Fruit growers in the mid-west. Changes/Problems: Timing of mist-cooling will be further refined by adding the factors of wind speed, and a phenological method of estimating the initiation of cooling based on on the early developmet of pollen grains (which occurs after endodormancy has completed). What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? They have been disseminated at two grower meetings, and with two different orginizational leaders in the fruit industry. Also preliminary results have been published in Good Fruit Grower Magazine (author Dick Lenhart, 2013). The concept was presented at the Great Lakes Expo in Decenber of 2013. What do you plan to do during the next reporting period to accomplish the goals? We plan on replication the mist-cooling projects at 4 different loctions in Michigan. The photosynthetic work on grasses, grape, and apple trees will not continue.
Impacts
What was accomplished under these goals?
Research focused on two major areas: 1) Providing support in determine photosynthetic rates, and 2) Mitagating the effect of warm temperature on early flower development of apple and cherry using Mist Cooling. Photosynthetic determinations led to the following major conclusions. Under objective 1. In grapevines (Vitis vinifera L.) infestation of E. fabae (potato leafhopper) caused injury through rapid effects on the capacity of the leaf to produce photosyntate through internal damage on tissues, and to stomata. This could lead to irreversible damage, indicating that early control is necessary. In Strawberry we determined the effect of physical damage on photosynthetic capacity of strawberry (Fragaria x ananassa cv. Honeoye). We concluded that damage at 10, 20, and 30% of the leaf area resulted in decreased levels of photosynthesis. This result indicates that growers must take particular care in reducing the amount of physical damage to the leaves by either abiotic or biotic causes. When comparing the photosynthetic capacity of annual and perennial rye grass we concluded that perennial cereals operate below their maximum photosynthetic capacity, in contrast to annual wheat. We think by selecting for greater sink strength in perennial wheat, breeders may be able to achieve higher rates of photosynthesis and support higher yields in this new crop. Under objective 2. Recent changes in temperature and decrease in the ice cover in the Great Lakes region of the United States have significantly impacted commercial fruit production in surrounding fruit growing areas. Michigan’s apple and cherry production was significantly reduced in 2012 because they experienced the earliest full bloom on record followed by several killing spring frosts. Bud development is driven by the localized accumulation of heat units once endormancy has been satisfied. Previous studies have shown that reducing bud temperature can delay bud break. Evaporative cooling with water prior to the onset of growth has been used (mid 70’s and early 80’s) in the past to delay early development of flowers. One to three weeks delay were observed; however, there often was a decrease in fruit set, and an increase in disease, and an over use of water. This study re-examines mist-cooling to delay bloom by bringing together three new or refine technologies for application of water by mist via a new pesticide application system, the solid set canopy delivery system (SSCD), modern weather sensing and control systems, and evaporative cooling application based on changes in temperature and humidity. The main objective was to suppress the temperature of cherry and apple buds to delay phenological development and limit potential frost damage. A second objective was to minimize the negative side effects of poor fruit set, and increased disease by more precise application of water for cooling. In 2013 an SSCD system was set up at three different locations in Michigan on sweet cherries, and apples to test the feasibility of the system. Three treatments were: no misting, misting from the first week in May until first flower, and misting from the first week in May through full bloom. Treatments delayed full bloom 7-10 in both cherry and apples depending on the variety and location for misting through full bloom when compared with the control. Turning the misting off at first bloom resulted in 2-3 days earlier full bloom. No significant difference was seen in fruit set, or disease. By midseason fruit development had almost caught up with the control in apples depending on the variety. At one site, frost damage (May 12) was significantly reduced by mist application. The system resulted in a significant savings in the amount of water applied over previously reported studies.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
A.Z. Makaraci and J.A. Flore. 2012. Determination of physical damage thresholds of strawberry leaves (Fragaria x ananassa cv. Honeoye). J. of Food, Agriculture and Environment. 10:376-380.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
M.S. Lenz, R. Isaacs, J.A. Flore, and G.S. Howell. 2012. Photosynthetic performance of pinot gris (Vitis vinifera L.) grapevine leaves in response to potato leafhopper (Empoasca fabae Harris) infestation. Am. J. Enol. Vitic vol. 63 no. 3 357-366
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
N.S. Jaikumar, S.S. Snapp, J.A. Flore, and W. Loescher. 2013. Photosynthetic responses in annual ryt, perennial wheat and perennial rye subjectied to modest source/sink ratio changes. Crop Science 4:0280
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
G.A. Lobos, J.B. Retamales, J.F. Hancock, J.A. Flore, S. Romero-Bravo, A. del Pozo. 2013. Productivity and fruit quality of Vaccinium corymbosum cv. Elliott under photo-selective shading nets. Scientia Horticulturae:V153 pp143149
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Rufus Isaacs, Steve Van Timmeren, Marcel S. Lenz, G. Stanley Howell, James A. Flore, Pat Murad and Paolo Sabbatini. 2012. Vine Responses to Potato Leafhopper at Leaf and Vine Scales: Implications for Vineyard Management. Am. J. Enol. Vitic December 2012 vol. 63 no. 4.
- Type:
Conference Papers and Presentations
Status:
Submitted
Year Published:
2013
Citation:
J.Flore, G.Lang, and I.Rijal. 2013. Mist-cooling to delay bloom and prevent frost, old idea new technology. Poster 5th International conference on plant dormancy, August 4-7,2013. Auckland NZ.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Developed a protocol for the mechanical harvest of stem-on brine sweet cherries. The above has a significant economic impact on brine cherry producers, growers typically receive 3-4X $ per pound from the processor over non stem-on cherries Developed carbon footprints for Michigan apple and sour-cherry orchards, which indicated orchards sequester carbon or are carbon neutral. Developed formula based on trunk cross sectional area that predicts the available fuel stock available from trees once they are removed for replanting. Data indicates that enough energy could be produced to be used in the farm or processing industries. A solid Set Canopy Delivery system infrastructure which included plastic piping, polyethylene hoses, pressure regulated valves and micro-sprayers was established in four plots in Michigan at Clarksville Research Station and on campus at the Horticulture Research and Teaching Center. Two high-density apple trials, on 3 acres were established at Clarksville for comparing application of water and chemicals in control, SSCD and tractor pulled ground-rig sprayer. Testing resulted in optimum delivery rates in operation of the system comparable to traditional sprayer system. A similar system was established on sweet cherries at this venue and a limited size unit established on apples on MSU campus. The system was successfully operated on October 3, 2012 to the public. Growth Regulators (natural or synthetic compounds which alter the physiology or morphology or a plant) are locally systemic compounds that must be applied uniformly, retained by the leaf or plant organ, be absorbed, and translocated to a site of action before a response can occur. The response is dose dependant, therefore application must be uniform and environmental conditions must be with in a specified range. To test the SSCD system we developed a bioassay based on the evolution of ethylene from leaves where ethephon was applied using the SSCD system. We found the uniformity of results equal to or greater than air blast application. Preliminary experiments indicated that the ethephon should be applied when temperatures are between 20 and 30 C; that the application on the leaf should be dry before leaf harvest for ethylene determination. Determinations can be made from 4 to 24 hours after application, and that leaves may be stored in test tubes with 1 ml of water placed in the bottom of the tube with the petiole placed in the water so transpiration may occur. The tubes can be stored at temperature between 10 and 30 C in the light or dark as long as the conditions are uniform for all samples. Once the incubation period has passed, tubes are capped and ethylene is determined after 60 minutes. After ethylene determination leaves are removed blotted dry and fresh weights are determine. Data are expressed as micro liters of ethylene per gram fresh weight per hour. Results have been disseminated through grower meetings, The Great Lakes Expo (every December) scientific meetings, and grower field days. PARTICIPANTS: Information generated were shared with both the Michigan Apple Research Committee and the Michigan Cherry Research Committee. TARGET AUDIENCES: Michigan fruit growers and processors, members of the National and International Horticultural Societies. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The protocol developed for the mechanical harvest of stem-on brine sweet cherries has a significant economic impact on brine cherry producers. Growers typically receive 3-4X $ per pound from the processor over non stem-on cherries. When growers remove orchards they typically burn the waste. However we have determined that the available fuel stock from trees once they are removed for replanting could provide enough energy be used in the farm or processing industries. The development of new natural gas supplies in Michigan has reduced the importance of this finding.
Publications
- Lenz, S., Issacs, R., Flore, J., and Howell, G. 2012. Photosythetic performance of Pinot girs (Vitis vinifera L.) grapevine leaves in response to potato leafhopper (Empoasca fabae Harris) infestation. AJEV 63-3. p357-366.
- Lobos, G. A., Retamales, J. B., Hancock, J. F., Flore, J. A., Cobo, N., and del Pozo, A. 2012. Spectral irradiance, gas exchange characteristics and leaf traits of Vaccinimu corymbosum L. `Elliott' grown under photo-selective nets. Environmental and Experimental Botany 75 (2012) 142-149.
- Toselli, M., Perry, R. L., and Flore, J. A. 2011. Evaluation of Nitrate-Nitrogen leaching from lysimeter-grown bearing apple trees. Soil Science V 176, June 2011 p 263-271
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Currently the apple and cherry industries are considering if these commodities might qualify for trading carbon credits on carbon exchanges. We have estimated tree carbon assimilation and sequestration using the apple carbon balance model of Lakso et al, 2001. Using that data we have also estimated the carbon footprint for both apple and cherry (Great Lakes Expo, 2009, 2010). We also focused on an alternate method of estimating lifetime dry matter accumulation for both apple and cherry and relate it to TCSA. Dry matter was measured in the fall of 2009 and 2010 for cherry and apple at three different sites. Total biomass in the perennial structure of trees was measured from trees excavated, and trunk circumference was measured for each tree, 45 cm aboveground. The study was conducted on 27 apple trees (cultivars:Gala,Red Delicious, Red Chief and Mutsu on different rootstocks) and 20 Montmorency cherry trees (10 and 30 years old). Trees total dry weight (kg) was found to be linearly correlated with TCSA (cm2) in apple (DW= 0.30*TCSA; R2=0.97) and cherry (DW = 0.40*TCSA R2=0.95). Similar regression equations can be applied selectively to aboveground trees dry biomass (DW= 0.22*TCSA; R2=0.95 for apple and DW= 0.25*TCSA; R2=0.96 for cherry) and root dry biomass (DW= 0.08*TCSA; R2=0.93 for apple and DW= 0.15*TCSA; R2=0.93 for cherry). On the trunk sections sampled, we measured cross sectional area growth according to growth rings, and used it to estimate annual dry biomass sequestered by single trees. Mean annual dry biomass sequestered was 4.5 kg/tree in 30 years old cherry trees, and varied from 1.1 to 2.7 kg/tree in apple trees, where the variability may be explained by the different age, rootstocks and cultivars of the trees employed. This study has led to the development of a project that is looking at reducing the cost and CO2 emissions of fruit processing in Michigan through the use of discarded fruit trees as a source of heat and electricity. Fruit trees in Michigan are removed on a 10-30 year cycle (average 20 years). Once removed, they must be disposed of. Currently this is accomplished by burning, which has been banned in some townships, or by leaving the material to decompose. Both of these waste a valuable energy resource. This research is investigating the feasibility of using removed fruit trees as a source of biomass energy in a combined heat and power system to offset some or all of the energy costs related to the processing side of fruit production and to lessen industry dependency on the large quantities of fossil fuels (natural gas) used in fruit processing. Currently we are determining the feedstock available from mature trees based on the existing acreage by mapping out the current acreage within a Fruit Cooperative in Northwest Michigan (6,000 acres) plus biomass from pits, pallets, transport boxes, and general wood waste from operations. In addition using tree fruit surveys of Michigan we are also estimating the feedstock in the entire state of Michigan. Preliminary data indicate that standing biomass estimates from cherry wood would be approximately 270 (BDT bone dry tons) for Michigan. PARTICIPANTS: Collaborators in this project were: Dr. Alan Lakso, Cornell University, and growers in the state of Michigan TARGET AUDIENCES: Target audiences for this research are: The Michigan Cherry Research Committee, The Michigan Apple Research Committee, The Michigan Horticulture Society, and fruit growers in Michigan PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Based on our studies, both cherry and apple production in Michigan have positive carbon footprints. Neither one is large, but they're both positive. They become less positive when using dwarfing rootstock which have greater harvest indexes than standard tree. However, the burning of trees at the end of their lifecycles, negates the effect of sequestration. We are conducting a feasibility study to determine if the biomass from these trees can offset the need for fuels. Therefore we have estimated the standing biomass of fruit trees in the state to be about 270 DBM, which could be used in a conventional boiler system to offset heat and electrical energy generation from other sources. This is already a common practice in California. Growers often receive premium prices (4x those with no stems) for sweet cherries harvested with stems-on. We have demonstrated that sweet cherries can be harvested stem-on for the brine industry, and can make the following recommendations. The variety Emperor Francis can be harvest when the fruit are 4.5-5 grams in weight, for 4-10 days until the lower abscission zone can be broken with 300 grams of force or less. The length of the harvest period seems to be related to DD accumulation of 250-300 on a 45 degree F base. % stem-on is usually highest around sunrise, and does not seem to be related to temperature.
Publications
- Toselli, M., Perry, R. L., and Flore, J. A. 2011. Evaluation of Nitrate-Nitrogen leaching from lysimeter-grown bearing apple trees. Soil Science V 176, June 2011 p 263-271. Lobos, G. A., Retamales, J. B., Hancock, J. F., Flore, J. A., Cobo, N., and del Pozo, A. 2012. Spectral irradiance, gas exchange characteristics and leaf taits of Vaccinimu corymbosum L. Elliott grown under photo-selective nets. Environmental and Experimental Botany 75 (2012) 142-149.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: The processed sweet cherry industry currently pays a premium for stem-on fruit for maraschino production, yet has difficulty obtaining adequate domestic supplies to meet demand. Michigan cherry growers who could shift current production from stem-off to stem-on fruit would have a strong economic opportunity if effective yields (orchard yield + yield after brining). The inherent challenge for stem-on fruit production is that two abscission zones (AZ) are present, with a natural shift in activity at the branch-pedicel AZ (#1, resulting in stem-on fruit) during early fruit development to activity at the pedicel-fruit AZ (#2, resulting in stem-off fruit) during fruit ripening. We continued our research (begun in 2009) on a maturity and mechanical harvest study that involved Emperor Francis, and Gold, at two different sites in NW Michigan. The 2010 season was the warmest in the last 10 which resulted in a harvest that was 14-17 days ahead of normal, and also resulted in a compressed ripening period. As a result t 'Emperor Francis' could only be mechanically harvested successfully with stems-on during a 2-4 day period and 'Gold' was not suitable for stem-on harvest. Successful stem-on harvest was dependant upon the size of the fruit (4.0-5gm), the velocity of the shake, and the fruit retention force of the AZ #2 (must be greater than 500 gm, up from the 300 reported last year). The variety Honeycrisp is currently the most profitable variety in the apple industry. However, this variety tends to be strongly biennial, which leads to very low crops one year and high crops the next. During the 2009-2010 grow season we confirmed that crop load is inversely related to return bloom. High crop loads (more than 6 fruit per cm2 cross sectional area of the trunk TCA) results in few flowers the net spring. The optimum range continued to be 4-6 fruit pre TCA. Adjustment of crop load in this range is not sufficient to assure adequate return bloom for all trees. We confirmed that trees thinned within this range, with only 1 lateral fruit per spur thinned (4-6 fruit/cm2 trunk cross sectional area) were larger, had more return bloom, and less bitter pit than trees thinned to 2 or 3 fruit per spur at the same fruit density. In another study relative to the carbon footprint of apple and cherry orchards under Michigan conditions we found a linear relationship between the cross sectional area of the trunk 20 cm above the soil and the root, shoot, and total dry weight of the tree. By determining the change in cross sectional area of the trunk yearly (from the annual rings) we could estimate the increase in standing dry weight per year. This data coupled with carbon sequestration from the grass ground cover minus fossil fuel carbon resulted in an estimate of carbon sequestered per year. PARTICIPANTS: Participants were: Lynne Sage technician responsible for work with Honeycrisp apple, currently working on a Ph. D. degree. Letizia Tozzini, research on carbon footprints, working on a Ph.D. degree. Nikki Rothwell (Northwest Michigan Horticultural Research Station), and Doris Sullivan (MSU technician) helped with the stem-on project. The Michigan Cherry Research Committee, and the Michigan State Horticultural Society provided funding in support of the stem-on Project. The Michigan Apple Research Committee supported the Honeycrisp project, and all three organizations funded the carbon footprint work for apple and cherry. TARGET AUDIENCES: Professional horticulturists, Michigan and NY apple growers and their organizations, and Michigan cherry growers and processors. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The studies in this project will help to establish biotic and abiotic thresholds based on carbon assimilation and storage for apple and cherry grown in Michigan. The studies also will help growers harvest stem-on brine cherries mechanically; and to increase the reliability of return bloom in Honeycrisp apple. The results from the cherry and apple studies have been reported nationally (American Society for Horticultural Science) and locally (Michigan Great Lakes Expo) each year of the project. Power Point presentations and posters from meetings concerning the projects can also be found at http://www.hrt.msu.edu/faculty/flore.htm
Publications
- Lanari V., Sabbatini P., Silvestroni O, Flore J.A. 2010. Water stress effect on growth, photosynthesis and carbon isotope discrimination in Vignoles potted vines. Italus Hortus, vol 17, pp 128-133.
- Sage L. E., Flore J. A., Tozzini L. 2010 Regulation of Return Bloom in Honeycrisp Apple: Fruit per Spur. HortScience 45 (8) S151.
- Tozzini L., Sabbatini P., Flore J. A. 2010. Effect of Nitrogen Foliar Application on Translocation of 15N and 13C in Seyval Blanc Grape. HortScience 45 (8) S139.
- Tozzini L., Flore J. A., Lakso A. N. 2010. The Carbon Footprint of Cherry and Apple Orchards in Michigan: an Allometric Study to Support Early Development of a Carbon Sequestration Model. HortScience 45 (8) S254.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: The processed sweet cherry industry currently pays a premium for stem-on fruit for maraschino production, yet has difficulty obtaining adequate domestic supplies to meet demand. Michigan cherry growers who could shift current production from stem-off to stem-on fruit would have a strong economic opportunity if effective yields (orchard yield + yield after brining). The inherent challenge for stem-on fruit production is that two abscission zones (AZ) are present, with a natural shift in activity at the branch-pedicel AZ (#1, resulting in stem-on fruit) during early fruit development to activity at the pedicel-fruit AZ (#2, resulting in stem-off fruit) during fruit ripening. We conducted a maturity and mechanical harvest study on three varieties Emperor Francis, Gold, and Ulster during the 2009 growing season. We found that 'Emperor Francis' and 'Ulster' could be mechanically harvested successfully with stems-on; while 'Gold' could not. Fruit were torn from the branch with the stem-on and we hypothesized that this occurred when sufficient centrifugal force was applied to the cherry. Successful stem-on harvest was dependant upon the size of the fruit (4.5-5gm), the velocity of the shake, and the fruit retention force of the AZ #2 (must be greater than 300 gm). The variety Honeycrisp is currently the most profitable variety in the apple industry. However, this variety tends to be strongly biennial, which leads to very low crops one year and high crops the next. Crop load is inversely related to return bloom. High crop loads (more than 6 fruit per cm2 cross sectional area of the trunk TCA) results in few flowers the net spring. The optimum range has been determined to be 4-6 fruit pre TCA. Adjustment of crop load in this range is not sufficient to assure adequate return bloom for all trees. Our working hypothesis is that the king fruit in a fruit bud has a greater influence on return bloom than lateral fruit, manifested either through growth rate or seed production of GA (gibberellic acid) which inhibits flower bud initiation (FBI) in that spur for the next season. We found that trees with only 1 lateral fruit per spur thinned (4-6 fruit/cm2 trunk cross sectional area) were larger, had more seeds, more return bloom, and more bitter pit than trees thinned to 1 terminal fruit per spur (same crop load). In another study we have been investigating the foliage damage threshold for sour cherry. We are modifying two previous models (CherryGrower) and the Lakso apple model to predict carbon production in cherry. Previous work we determined that 2 leaves per fruit were needed to mature a crop, and that fewer leaves reduced cold hardiness. Defoliation experiments have been set up to simulate the loss of foliage during the season. From these studies we have developed a model that predicts loss of wood hardiness based on the % good foliage (Leaf retention x duration) and tree vigor (length of terminal growth, low = <10 cm, high >20 cm). We estimate that less than 70% for low vigor and 55% for high vigor trees will reduce cold hardiness of terminal shoots on 'Montmorency' sour cherries under Michigan conditions. PARTICIPANTS: J. Flore is PI, and has ultimate responsible for all research decisions and reporting activities. TARGET AUDIENCES: The target audience for the outcomes of this project is the cherry growers of Michigan. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The studies in this project will help to establish biotic and abiotic thresholds based on carbon assimilation and storage for apple and cherry grown in Michigan. The studies also will help growers harvest stem-on brine cherries mechanically; and to increase the reliability of return bloom in Honeycrisp apple. The results from the cherry and apple studies have been reported nationally (American Society for Horticultural Science) and locally (Michigan Great Lakes Expo) each year of the project. Power Point presentations and posters from meetings concerning the projects can also be found at http://www.hrt.msu.edu/faculty/flore.htm
Publications
- Lobos, G.A., Retamales, J.B., del Pozo, A., Hancock, J.F. and Flore, J.A. 2009. Physiological response of Vaccinium corymbosum Elliott to shading nets in Michigan. Acta Hort. (ISHS) 810:465-470.
- Flore, J., Lang, G. A., Rothwell, N., and van Nocker, S. 2009. Mechanical Harvest of Stem-on Sweet Cherries (Prunus avium L.) for the Brine Trade. ISHS Cherry Symposium (abstract).
- Makaraci, A.Z. and Flore, J.A. 2009. The use of chlorophyll fluorescence to determine the effects of different acclimation temperatures on strawberry leaves exposed to mild frost damage. Acta Hort. (ISHS) 842:813-816
- Flore, J.A. and Sage, L.E.T. 2009 Regulation of Return Bloom in Honeycrisp Apple: Fruit Position and Seed Number, HortScience 44:1074
- Lenz, M.S., Isaacs, R., Flore, J.A., Howell, G.S. 2009. Vegetative Growth Responses of Pinot gris (Vitis vinifera L.) Grapevines to Infestation by Potato Leafhoppers (Empoasca fabae Harris) Am. J. Enol. Vitic. 60:2:130-137 (2009).
- Sabbatini, Paolo, Lanari, V., Silvestroni, O., Flore, J. 2009. Physiological Effects of Water Stress on Seyval Potted Vines. Italus Hortus (in press).
- Lanari V., Sabbatini P., Silvestroni O., Flore J., 2010. Physiological effects of water stress on Seyval potted vines. American Journal of Enology and Viticulture (submitted).
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: The effect of environmental and biological stress has been studied for pome and stone fruit under Michigan conditions. Currently experiments are being conducted on Montmorency sour cherry, and Honeycrisp apple. Results have been presented at several industry meetings including The Great Lakes Fruit, Vegetable and Farm Market Expo in Grand Rapids, The Traverse City Farm and Orchard Show, and internationally at an ISHS (international Society for Horticultural Society) conference in Geneva NY. Poster concerning this work have also been placed on our Department web page www.hrt.msu.edu/faculty/flore.htm. PARTICIPANTS: Jim Flore, P.I. Lynne Sage, technician. Responsible for hardiness determination, and fruit quality evaluation. Phil Schwallier, district extension agent. Responsible for the culture of trees Letzia Tozzini, graduate student, working on a cherry carbon assimilation model TARGET AUDIENCES: The fruit growers of Michigan, and peer research personnel on a national and international level. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Montmorency sour cherry production and quality are dependent upon the supply and demand for carbon. The leaves are the primary organs responsible for photosynthesis in cherry. Since leaves are only on the tree about 7 months out of the year, any damage to the leaves will reduce the supply of carbon. Several approaches have been taken to determine the effect of foliage damage on current and next seasons fruit production. Experiments were conducted to determine the effect of leaf damage on both current and next years crop. Two approaches were used to model the supply of carbon. One, the Lakso Apple model of carbon supply and distribution for apple was modified for cherry (now about 70% complete) and two, modification of Cherry Grower a model based on Degree Days and past vigor is proposed and being modified to predict if supply and demand for carbon were in balance. It was hypothesized that storage starch in the root or shoot could be a good indicator of performance the next year. We did not find a good association between Starch content and return yield or hardiness unless values were extremely low. We developed a set of leaf damage thresholds for Montmorency cherry grown under Michigan conditions. On trees, with greater than 20 cm of terminal growth, foliage must be reduced by approximately 50% for the duration of the season before there is a substantial decrease in deep winter hardiness. Reduced vigor (less than 10 cm growth, shading, or foliage damage due to mites) begins to decrease hardiness at 65-70% foliage. The variety Honeycrisp is being widely planted by Michigan growers. It has outstanding flavor, crispness, and market demand. It currently is the most profitable variety in the industry. However, uniformity and regulation of fruit size and return bloom can greatly be influenced by crop load and tree vigor. This variety tends to be strongly biennial, which leads to very low crops one year and high crops the next. The objectives of this study were to:(1) conduct a detailed study on the effect of crop load on return bloom in relation to tree and seasonal variability, and (2) on crop quality (fruit firmness, total acidity, soluble solids, color and starch). This was accomplished by establishing 5 or 6 different crop loads (control, low, medium, high) at 4 different sites in two different years (2006, 2007) crop loads were adjusted by hand thinning. We also conducted a survey on several (n=9) different orchards in different locations (n=4) within Michigan. Results from two years indicate the following: There was a direct effect of crop load on current seasons crop quality. There was a strong relationship between crop load and next years bloom, however crop load was not as negatively related to next years yield. Yellowing was related to crop load and was positively related to return bloom Photosynthesis was highly related to crop load. The information from this study will help producers have a better understanding of the factors that influence flower bud initiation and how they can improve annual cropping.
Publications
- Mota-Sanchez, D., Hoffmann, E.J., Flore, J., and Wise, J. C. 2008. Penetration of 14c-insecticides (imidacloprid, thiacloprid, thiamethoxam and indoxacarb) in apples to optimize insecticide performance in fruit pest management. Abstract American Entomological Society of America (electric conference proceedings).
- Flore, J., Sabbatini, P., Sage, L., and Schwallier, P. 2008. Management of crop load and vegetative growth on Honeycrisp to optimize fruit size, fruit quality, return bloom and fruit set. 9th International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems, Aug 4-8, 2008 abstract 130 p. 159.
- Flore, J. 2008. Carbon supply, demand, and storage in relation to current seasons growth and the following years yield. 9th International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems, Aug 4-8, 2008 abstract 131 p 160
- Lanari V., Sabbatini P., Silvestroni O., Flore J., 2008. Physiological effects of water stress on Seyval potted vines. Proceedings II National Viticulture Conference, Sicily, Italy.
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Progress 01/01/07 to 12/31/07
Outputs
Three specific projects are reported on for 2007. Source-Sink Relationship: Effect on Crop Load, Photosynthesis and Carbon Isotope Discrimination of Imperial Gala Apple trees. The reported are over a three-year study. The natural carbon isotope composition (or 13C/12C ratio) of plant tissue is extensively used as an indicator of water use efficiency during plant growth, and is a powerful investigative tool for physiological responses of plants in different environmental conditions (e.g. water stress). In a three-year study (2005,2006, and 2007) we tested if 13C/12 ratio could be an indicator of carbon source limitations (optimum water conditions); where there may be an imbalance between source supply and sink demand during fruit growth. We hypothesized that since photosynthesis and stomata1 conductance of low crop load trees (64 leaves per fruit) had lower rates in the afternoon, that it would be logical for the 13C/12C ratio of carbon from different organs to change.
We found that stable carbon isotope discrimination was reduced significantly in low cropping trees (minus 25.52) and was increased(minus 27.82) in high cropping trees. Discrimination was inversely related to crop load and was a more sensitive indicator of source limitations that leaf photosynthesis. Tissues in close proximity to the fruit (sinks) were more sensitive than tissues at greater distances (shoots and roots). In a separate experiment to alter source to sink ratios during the season, we manipulated time (fruit set, 50 and 75 percent of full fruit size) and degree of defoliation (25, 50 and 75 percent) on different crop load (4, 16 and 32 leaves per fruit) trees. Our objective was to determine if immediate changes in fruit growth, leaf photosynthesis and 13C/12C ratio (of leaves and starch) could be detected. We found that leaves from low cropping trees responded within 24 hours. In midsummer we found a significant change in the 13C/12C ratio of starch (extracted 24 hours
after defoliation) on low-cropped trees. This research indicates that either leaf photosynthesis determined in the afternoon on a sunny day, or the 13C/12C ratio of extracted starch can be sensitive to source sink alteration. More research is needed before we can determine if either of these techniques can be used as a diagnostic tool to determine source limitation. This has important implications concerning the threshold for leaf damage. In another study we have been investigating the foliage damage threshold for sour cherry. We are modifying two previous models (CherryGrower) and the Lakso apple model to predict carbon production in cherry. In previous work we determined that two leaves per fruit were needed to mature a crop, and that fewer leaves effected cold hardiness as well as current crop growth and maturity. Defoliation and photosynthetic inhibition (with herbicides) have been set up to simulate the loss of foliage during the season. Results on cold hardiness are not yet
complete.
Impacts
The studies in this project will help to establish biotic and abiotic thresholds based on carbon assimilation and storage for apple and cherry grown in Michigan. The results from the cherry and apple studies have been reported nationally (American Society for Horticultural Science) and locally (Michigan Great Lakes Expo) each year of the project.
Publications
- Lobos, G., Sabbatini P., Flore J., Del Poso, A. and Retamales, J. 2007. Crop load and time of defoliation in imperial gala apple trees: effect on photosynthesis, fruit growth and yield. HortScience 42:4.
- Sabbatini, P. and Flore, J. 2007. Sink-source relationship: effect on crop load, photosinthesis and carbon isotope discrimination of Imperial gala apple tree. HortScience 42:4.
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Progress 01/01/06 to 12/31/06
Outputs
Trees of Imperial Gala/Bud 9, 8 years old, field grown at the Clarksville Horticultural Research Station (Clarksville, MI), were hand manipulated at fruit set to three different levels 8.1, 29.1 and 46.6 leaves per fruit. A high crop load level of 4 leaves per fuit was not possible because fruit set was not sufficient. Net photosynthetic rate (A) of leaves, fruit and shoot growth were monitored during the season. Biological damage was simulated by removing 50 percent of every other leaf (25 percent reduction in effective leaf area) at three different intervals (July 8, July 25, and Aug. 19) during the season. Selective spraying of individual leaves or whole trees with terbacil to inhibit leaf photosynthesis did not provide significant reduction in photosynthesis for more than seven days, so it was not used as a technique to simulate damage. Leaf and fruit samples for carbon (including 13C/12C ) analysis were taken at 14 to 21-day intervals during the season and were
compared to significant changes in fruit size and photosynthetic activity of the trees. Leaf starch was extracted 4 days after defoliation, and then again at 14 to 21 day intervals. All data are not yet fully analyzed. The data analyzed indicate the following. At harvest, leaf to fruit ratio had a significant effect on: total yield per tree (increased with fruit number); fruit size increased (no increase between medium and low crop); shoot length (increased as leaf to fruit ratio increased); leaf chlorophyll increased from low to medium crop load, but not between medium and high crop load. The defoliation treatments had no effect on final fruit size or yield, at any of the crop loads (non significant for all the above parameters) This indicates that removal of the 25 percent of the trees leaf area in midsummer (July 8) had no significant effect on the current seasons crop. The first defoliation treatment occurred at 40 percent of the growing season (by time) when the fruit had
accumulated 60 percent of their final size. However, growth analysis indicated that by that date there was a significant difference in fruit size due to crop load. Crop load adjustment was done at the end of fruit set (June 7-10), when fruit had attained 30 percent of final growth. Manipulation of source sink ratios therefore had a very significant effect when done early in the season, near the end of cell division, while a major defoliation treatment (25 percent) 30 days later had no significant effect. These data have important implications for management decisions concerning pest control depending upon the time of season that the infestation occurs. Even though there were no differences at the end of the season in fruit quality due to defoliation, there was a difference in photosynthesis and stomatal conductance due to the first defoliation at the medium crop load. Although not all tissues from all dates have been analyzed, in the samples analyzed there was a significant change in
the 13C/12C ratio of the starch extracted at the end of the day, four days after treatment, in the moderate crop load trees.
Impacts
It is expected that isotope discrimination may be a diagnostic tool to determine if source limitation has occurred. If this technique is sensitive enough, then it may be possible to change management decisions during the season to relieve the source limitation (by pest control, crop removal, or increased vigor using other horticultural techniques). We have shown that it is related to crop load, and that differences can be detected in starch from leaf tissue. Early results show considerable promise.
Publications
- Zavalloni, C., Andresen, J.A., Winkler, J.A., Flore, J.A., Black, J.R. and Beedy, T.L. 2006. The pileus project: climatic impacts on sour cherry production in the Great Lakes region in past and projected future time frames. Acta Hort. (ISHS) 707:101-.
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Progress 01/01/05 to 12/31/05
Outputs
Apple seedlings, Malus domestica Borkh, were grown under ambient 370, 700, and 1400 umol-1 CO2 regimes and artificially damaged by removal of leaf area 0, 15, and 30 percent. Increased CO2 concentration had a highly significant effect on the concentrations of sucrose, sorbitol and phloridzin, however there were no significant interactions between CO2 concentration and leaf damage. As CO2 concentration increased there was an increase in levels of sucrose and phloridzin, whereas sorbitol concentration decreased. These findings are discussed in relation to the carbon nutrient balance hypothesis as well as other hypotheses regarding the production of plant primary and secondary compounds in response to elevated levels of CO2 and mechanical damage and/or herbivory. In experiments we conducted at CHES on 'Gala' apple in 2004-5 we found that crop load is a critical regulator of production and quality on apple. It affects leaf photosynthetic rate; increasing crop load
increased the photosynthetic activity, and low crop load down regulate leaf photosynthetic rates. Total yield per trees was modified and also fruit size distribution. Variations of the stable carbon isotope composition show an increase of 13C concentration in fruit and shoot tissue due to a reduction of discrimination. This reduction is correlated to photosynthetic performance of the trees. We propose to take this research one step further, to determine if source limitations could be predicted by natural carbon isotope discrimination in the new leaves and fruit on a tree. Soft cherries after harvest. GA did not improve the percent of good fruit after harvest. Ethephon treated trees had slightly higher quality fruit than the non-sprayed controls Late season application of ethephon did not affect fruit quality significantly. However, quality declined with maturity as measured by a decrease in fruit retention force. The best method to predict fruit maturity is measuring fruit retention
force. Optimum quality was obtained at FRF of 300 grams. Quality declined from 98 percent at 300 grams, to 90 percent at 220 grams FRF. Copper had a positive effect on fruit quality in 2003 and 2005. Quality decreased with tree height. Tree 15ft tall had 90 percent good fruit, while trees greater than 18 ft had just over 60 percent good fruit.
Impacts
Environmental and management practices strongly effect the yield and quality of cherries and apples grown under Michigan conditions. Crop load thresholds on Gala apple result in increases of 13C in the apple tissue. This indicates source limitation (not enough phothosynthetic capacity to sustain fruit growth). Determining the amount of 13C, may be a good diagnostic tool for predicting source limitation during the season.
Publications
- Zavalloni C., J.A. Andresen, and J.A. Flore 2006. Phenological Models of Flower Bud Stages and Fruit Growth of 'Montmorency' Sour Cherry Based on Growing Degree-Day Accumulation. J. Amer. Soc. Hort. Sci (in press)
- Sabbatini P., Flore J.A., 2005. Effect of Crop Load on Diurnal Leaf Photosynthesis, Stomatal Conductance and annual Carbon Isotope Composition of Imperial Gala Apple tree. HortScience Vol 40 (4): pp 1996.
- Mark A. Kelm, James A. Flore, and Clifford W. Beninger. 2005. Effect of Elevated CO2 Levels and Leaf Area Removal on Sorbitol, Sucrose, and Phloridzin Content in Gala-Malling 9 Apple Leaves. J. Amer. Soc. Hort. Sci. 130:326-330.
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Progress 01/01/04 to 12/31/04
Outputs
Two studies on stress using strawberry as a model system were concluded. Damage thresholds of (Fragaria x annanasa) were investigated by mechanical damage (holes punched in leaves) to simulate 10, 20 and 30 percent damage, or by applying a photosystem II herbicide (Terbacil) to the leaves in concentrations from 12.5-400 ppm. Leaves did not recover photosynthetically following mechanical damage. Increasing levels of damage decreased the light saturation point and carboxylation efficiency. Plants treated with Terbacil were able to recover at all but the highest (400 ppm) concentration. Recovery time was inversely related to concentration. Strawberry did not compensate photosynthetically to leaf damage as reported for other crops investigated in our lab (apple, cherry), but did result in greater leaf formation. Cultivated strawberry is considered a salt sensitive crop, while its progenitors, Fragaria chiloensis and Fragaria virginiana, differ in sensitivity, with F.
chiloensis being more tolerant than F. virginiana. In this study, we sought to investigate the effect of salinity stress and recovery on photosynthetic performance, leaf area production and the accumulation of specific metabolites and inorganic ions. At early stages, stomatal conductance limited photosynthesis (Pn) in all species; later carboxylation efficiency was affected in F. virginiana but not in F. chiloensis. High levels of Na and Cl were detected in leaves of F. virginiana, while in F. chiloensis only Cl was not increased at the 50 and 100 mM levels. The physiological significance of this is yet to be determined. The question, Are dwarfing rootstocks of sweet cherries (P. avium) more efficient in N utilization than standard rootstocks? was investigated, using Mazzard, Giesla 5 and Giesla 6, with and without the scion variety Ranier. Overall, there were no differences in N-fertilizer uptake between dwarfing and standard rootstocks. However, nitrogen use efficiency (NUE) was
significantly higher in Mazzard, compared to the dwarfing rootstocks. Values of NUE were similar for Mazzard, and the dwarfing rootstocks when the scion Ranier was the scion. Similar results were found on five-year-old field grown Sam on Mazzard or Giesla 5. Under field conditions, N was absorbed in greater amounts when applied at bloom or at rapid shoot growth than at the beginning of leaf senescence. NUE, as well as N retranslocation from senescent leaves did not differ between rootstocks. The same rootstocks were evaluated for their water-use efficiency with Ranier as the scion under well-watered and water deficit conditions. Overall, WUE was not significantly different between dwarfing and standard rootstocks, and did not appear to increase under water deficit conditions, indicating that irrigation should be considered as an important practice in sweet cherry orchards, especially when dwarfing rootstocks are selected.
Impacts
Strawberry does not compensate photosynthetically for leaf damage; it compensates by making more leaves, therefore pest control of new leaves is critical. Giesla 5 and 6 dwarfing rootstocks do not improve N or water use efficiency when compared with mazzard standard. Since their roots explore less soil volume, they are more vulnerable to N deficiency and water stress.
Publications
- No publications reported this period
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Progress 01/01/03 to 12/31/03
Outputs
Two studies on stress using strawberry as a model system were concluded in 2003. Damage thresholds of (Fragaria x annanasa) were investigated by mechanical damage (holes punched in leaves) to simulate 10,20, and 30% damage, or by applying a photosystem II herbicide (Terbacil) to the leaves in concentrations from 12.5-400 ppm. Leaves did not recover photosynthetically following mechanical damage. Increasing levels of damage decreased the light saturation point, and carboxylation efficiency. Plants treated with Terbacil were able to recover at all but the highest (400-ppm) concentration. Recovery time was inversely related to concentration. Strawberry did not compensate photosynthetically to leaf damage as reported for other crops investigated in our lab (apple, cherry), but did result in greater new leaf formation. Cultivated strawberry is considered a salt sensitive crop, while it progenitors Fragaria chiloensis and Fragaria virginianna differ in sensitivity, with F.
chiloensis being more tolerant than F. virginiana. In this study we sought to investigate the effect of salinity stress and recovery on phothsynthetic performance, leaf area production, and the accumulation of specific metabolites and inorganic ions. At early stages stomatal conductance limited photosynthesis (Pn) in all species, later carboxylation efficiency was affected in F. virginiana but not in F. chiloensis. High levels of Na and Cl were detected in leaves of F. virginiana while in F. chiloensis only Cl was not increased at the 50 and 100mM levels. The physiological significance of this is yet to be determined. The question Are dwarfing rootstocks of sweet cherries (P. avium) more efficient in N utilization than standard rootstocks? was investigated, using Mazzard, Giesla 5 and Giesla 6 with and without the scion variety Ranier. Overall, there were no differences in N-fertilizer uptake between dwarfing and standard rootstocks. However, Nitrogen use efficiency (NUE) was
significantly higher in Mazzard compared to the dwarfing rootstocks. Values of NUE were similar for Mazzard, and the dwarfing rootstocks when the scion Ranier was the scion. Similar results were found on five-year-old field grown Sam on Mazzard or Giesla 5. Under field conditions N was absorbed in greater amounts when applied at bloom or at rapid shoot growth than at the beginning of leaf senescence. NUE, as well as N retranslocation from senescent leaves did not differ between rootstocks. The same rootstocks were evaluated for their water-use efficiency with Ranier as the scion under well watered and waters deficit conditions. Overall, WUE was not significantly different between dwarfing and standard rootstocks, and did not appear to increase under water deficit conditions, indicating that irrigation should be considered as an important practice in sweet cherry orchards, especially when dwarfing rootstocks are selected.
Impacts
Strawberry does not compensate photosynthetically for leaf damage; it compensates by making more leaves, therefore pest control of new leaves is critical. Giesla 5 and 6 dwarfing rootstocks do not improve N or water use efficiency when compared with mazzard standard. Since their roots explore less soil volume, they are more vulnerable to N deficiency and water stress.
Publications
- Zavalloni C. and Flore, J.A. 2003. Nitrogen uptake and use-efficiency of field-grown sweet cherry (Prunus avium L.) trees on dwarfing and standard rootstocks. HortScience 38:767. (Abstr.)
- Sabbatini, P., Zucconi, F., Flore, J.A. and Neri, D. 2003. Oscillatory bud dormancy during shoot growth and rest period in peach. HortScience 38:778. (Abstr.)
- Janoudi, A. and Flore, J.A. 2003. Effects of multiple application of methyl jasmonate on fruit ripening, leaf gas exchange and vegetative growth in fruit trees. J. Hort. Science and Biotechnology 78:793-797.
- Lakso, A.N. and Flore, J.A. 2003. Carbohydrate partitioning and plant growth. In Concise encyclopedia of temperate tree fruit, T.A. Baugher and S. Singha eds.,pp 21-28.
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Progress 01/01/02 to 12/31/02
Outputs
Soft cherries are a difficult problem for growers. We now have 3 years of data that indicate a strong association between fruit boron level and poor quality cherries as measured either by the splat test or from actual samples immediately after mechanical harvest. Correction by application of GA shows promise but is not yet proven. The practical implications of this work have been discussed at grower meetings (The NW field day in 2001; farm and orchard show 2002). Modification of nutrient recommendations have not yet been confirmed, but are under consideration. Influence of washing on blossom thinning by ATS in JonaGold apples. When ATS was applied at a concentration of 5 Percent at petal fall, washing had a significant effect on the blossom thinning activity of ATS. In ATS-treated trees that were washed one or two hours following the ATS treatment, the percentage of flowers that set fruit was significantly higher than that observed in trees that were not washed. All
ATS-treatment resulted in significantly lower fruit set percentages, ranging between 0.2 and 2.4 percent, as compared to the untreated control where fruit set reached 7.4 percent. Influence of washing on the level of ATS-induced damage in Manchurian Crabapple. Aqueous solutions of ATS at concentrations of 1, 2, 5 and 10 percent were applied to crabapple trees at 80 percent of full bloom stage. ATS-treated trees were then either not washed or washed at 30, 60, 120 or 240 minutes after the application of ATS. A hand-held sprayer was used to wash the trees at a rate of 400 ml of water per tree. There was a significant interaction between ATS concentration and the washing interval (time between ATS application and washing) for all parameters of damage assessment . Washing reduced the level of damage to open flowers that were treated with a 1 percent solution of ATS. The percentage of open flowers damaged by ATS at concentrations of 2 to 10 percent was not affected by washing, with 95 to
100 percent of the flowers being damaged by ATS. ATS applied at concentrations of 1 to 5 percent caused little damage to flowers that were closed at the time of treatment and washing had no significant effect on the level of flower damage at these concentrations. When ATS was applied at a concentration of 10 percent, washing significantly lowered the level of damage to the closed flowers. The 30 min. post-treatment wash decreased the incidence of damage in closed flowers to levels comparable to those observed in the 1 percent ATS treatment. Almost half of the closed flowers were damaged in unwashed trees treated with 10 percent ATS, as compared to only 7 percent flower damage in the 30 min. wash treatment. In the 2 and 5 percent ATS treatments, washing decreased leaf damage by 66 to 85 percent as compared to the damage observed in the unwashed trees. ATS at 1 percent damaged less than 1 percent of leaves in unwashed trees, which was not significantly different from the damage level in
the washed trees. Washing had no significant effect on leaf damage when ATS was applied at a concentration of 10 percent.
Impacts
Tart cherries which lack firmness at the time of harvest usually do not firm up during soaking. These soft fruit are hard to pit, often lose much of their internal tissue as the pit is removed and end up as crushed or mutilated in the can or freezer. Unfortunately marginally soft fruit is not observable until after the cherry has been mechanically harvested or physically handled. Losses to growers and processors are conservatively estimated at $6.3 M per year, but in some years losses are ore severe, i.e., 1992, 1995, and 1998 when losses averaged $14.3M (J. Nugent personal communication). Our results indicate that high fruit boron is associated with poor fruit quality. We suggest that application of foliar boron (which is a current standard practice) should be limited unless leaf boron levels indicate that the plant is deficient. The impact of such a recommendation on fruit quality industry wide has yet to be determined. Blossom thinning of fruit trees has been
unpredictable. This project quantifies the effect of environment on thinning response. The use of a high concentration of a caustic material followed by the application of an antidote (water) has shown promise.
Publications
- Flore J. A. and A. Janoudi. 2002. Improving the performance of blossom thinners. Great Lakes Expo Managing the uncertainties in growing and marketing fruitw and vegetables. pp 41-43.
- Zavalloni C. and J. A. Flore. 2002. Nitrogen- and water-use efficiency of sweet cherry (Prunsu avium, L) CV Ranier grown on mazzard and on Giesela dwarfing rootstocks. (abstract). XXVI International Horticultural Congress and Exhibition, Toronto, CA.Pp 346.
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Progress 01/01/01 to 12/31/01
Outputs
Experiments were conducted on several farms in Northwest to determine the effect of fruit load and boron on fruit quality after harvest. In addition we investigated the effect of copper and lime under field conditions. In 2000, and 2001 we adjusted crop load at shuck split and pit hardening. In general, low leaf to fruit ratios delayed ripening as indicated by delayed abscission, color, soluble solids and smaller fruit. Low leaf to fruit ratio did not decrease fruit firmness before harvest, and it did not decrease the number of good fruit after a simulated harvest. Application of boron increased boron content of the fruit at harvest, and resulted in a lower percentage of good fruit after harvest. Fruit with boron had greater color and appeared more advanced in maturity than control fruit. This suggests that boron may play a role by affecting cell wall integrity not associated with increased fruit set. Experiments with copper indicated that foliar sprays may improve
the percent of good fruit after harvest. Another study was conducted to investigate the partitioning of carbon 13 (13C) and the relationship between root C allocation and root respiration rate in `Redcort'/M.7 and rooted cuttings of B.9. Canopies were pulsed with 13CO2 and isotopic emissions from the soil were monitored after pulse labeling. Mildly water stressed potted trees were compared with a well-watered treatment. In `Redcort'/M.7, water stress, over a 7-day period, reduced predawn leaf water potential and root efflux rate of 13CO2. However, 13C partitioning to the roots was not reduced by low soil moisture. Evolution rate of 13C from the roots was not related to the amount of 13C allocated into the roots themselves. In B.9, 13CO2 emission from the soil was monitored for 16 days. A decrease in root respiration (up to 53% on the first day after the pulse) was the first response to soil water deficit treatment even when drought stress was not effective in reducing leaf gas
exchange. These results suggest that during water deficit conditions, roots appear to use a lower proportion of their total carbon content for respiration. 13C partitioning within the tree was not affected by water supply over the duration of the experiment.
Impacts
Tart cherries which lack firmness at the time of harvest usually do not firm up during soaking. These soft fruit are hard to pit, often lose much of their internal tissue as the pit is removed and end up as crushed or mutilated in the can or freezer. Unfortunately marginally soft fruit is not observable until after the cherry has been mechanically harvested or physically handled. Losses to growers and processors are conservatively estimated at $6.3 M per year, but in some years losses are ore severe, i.e., 1992, 1995, and 1998 when losses averaged $14.3M (J. Nugent personal communication). Our results indicate that high fruit boron is associated with poor fruit quality. We suggest that application of foliar boron (which is a current standard practice) should be limited unless leaf boron levels indicate that the plant is deficient. The impact of such a recommendation on fruit quality industry wide has yet to be determined.
Publications
- Lombardini, L., M. Toselli, and J.A. Flore. 2001. Leaf assimilation, carbon translocation and root respiration in apple rootstocks during moderate drought. Acta Horticulturae 557:413-420.
- Giuliani, R., M. Eugenio, and J.A. Flore. 2001. Infrared Thermography: Canopy Temperature Monitoring to Detect Water Stress on Fruit Trees. Acta Horticulturea 557:399-406.
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Progress 01/01/00 to 12/31/00
Outputs
Nitrogen-ammonium nitrate was applied to four `Mutsu' apple (Malus x domestica Borkh.) Trees 40 days before harvest of 1996 (summer supplied nitrogen, SUN) and four others at full bloom in 1997 (spring supplied nitrogen, SPN) to evaluate the effect of application timing on N partitioning in mature trees. At leaf fall the largest amount of SUN was partitioned to roots and 2 to 4 year old wood; the largest amount of SPN was partitioned to fruit and leaves and only a small amount detected in the roots. SUN did not increase N concentration in fruit or modify fruit firmness and soluble solids concentration, although it contributed to building up N reserves in the perennial woody organs. In 1997, as a result of the different timings of N supply, two sources of labeled N were distinguished and monitored in the vegetative organs: 1) the remobilized N, taken up in summer of 1996, stored in winter and then translocated to the growing tissues; 2) the newly absorbed N, taken up
and moved to the canopy after the 1997 spring supply. Both fractions of remobilized and newly uptaken labeled N contributed to leaf and fruit N. Remobilized N was provided principally by roots which, from August to leaf fall, decreased their percentage of N by 18%, replacing the labeled with unlabeled N to maintain a constant concentration of total N. Another project was conducted to investigate the allocation of labeled carbon and to understand the relationship between root C allocation and root respiration rate in apple rootstocks Budagovski 9 under drought stress. Canopies of 1 year old rooted cuttings of Budagovski 9 were pulsed with CO2 and isotopic emissions were monitored for 16 days after the pulse. Mildly stressed potted plants were compared with a well-watered treatment. A decrease in root respiration was the first response of soil moisture deficit even when drought stress was not effective in reducing leaf gas exchange. The lower soil moisture did not induce any effects on
predawn leaf water potential or single leaf net assimilation rate but it reduced the evolution rate of labeled CO2 from the root. Carbon partitioning within the plant was not affected by water supply over the 16 day duration of the experiment. We explain these results as a plant adjustment to the soil condition, which involves a higher fraction of carbon utilized for growth and consequently, a minor fraction of C assigned to metabolic activities. Evolution rate of C from the roots was not related to the amount of labeled C allocated into the roots themselves.
Impacts
The assimilation and partitioning of carbon and nitrogen are being investigated in relation to abiotic and biotic stress for fruit crops. This research will help to establish carbon thresholds for fruit crops.
Publications
- Giuliani, R., J.A. Flore and S. Breitkreutz. 2000. Potential use of Infrared therometry for the detection of water stress on peach and apple orchards. 7th International Symposium on Orchard and Plantation Systems, 20 Jan-5 Feb, 2000. Acta Horticulturae in press.
- Breitkreutz, B. and J.A. Flore. 2000. Whole plant photosynthesis of apple trees in an integrated pest management system. 7th International Symposium on Orchard and Plantation Systems, 20 Jan-5 Feb, 2000. Acta Horticulturae in press.
- Lombardini, L., M. Toselli, and J.A. Flore. 2000. Leaf assimilation, carbon translocation and root respiration in apple rootstocks during moderate water stress. 7th International Symposium on Orchard and Plantation Systems, 20 Jan-5 Feb, 2000. Acta Horticulturae in press.
- Giuliani, R., M. Eugenio, and J.A. Flore. 2000. Infrared Thermography: Canopy Temperature Monitoring to Detect Water Stress on Fruit Trees. Acta Horticulturea in press.
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Progress 01/01/99 to 12/31/99
Outputs
Remote sensing infrared thermometry was applied to estimate the canopy temperature of apple trees for early detection of water stress. The measurements were taken in Michigan during the summer of 1998 in a four-year-old apple orchard. Digital thermo-images of the canopy in relation to camera and sun positions were taken using an IR imaging radiometer on well-watered trees and trees in a water shortage condition; at the same time environmental (air and soil) conditions were also monitored. A software program was developed to analyze the thermal data, to show the thermal frequency distribution and to estimate the statistical parameters representing the physiological condition of the trees. An increase of the canopy surface temperature (connected to the partial stomatal closure affecting leaf energy balance) was detected early in the nonirrigated plants, i.e. when such physiological responses as photosynthetic activity and fruit growth were not yet adversely affected by
water deficit. The study confirms that there is a theoretical basis for the use of infrared thermometry and digital-image processing in early detection of water stress in fruit trees. Whole plant photosynthesis measurements. The objectives of this study were to determine the relationship of whole plant photosynthesis (WPP) and overall growth of apple trees to the damage caused by insects and disease. WPP was measured on sixty four apple trees of varieties Empire and Liberty at the Clarksville Horticulture Experiment Station, Clarksville, MI. WPP was measured on trees subjected to six pesticide and fungicide treatments that were part of an established IPM study and these measurements were conducted seven times during the 1997 growing season. Results showed a decrease in the rate of WPP as the season progressed for all treatments from a maximum of 1-5 micromol CO2.cm-2.s-1 to a maximum of less than 0.5 micromol CO2.cm-2.s-1. The soft IPM treatments have a higher rates of photosynthesis
than the conventional IPM treatments and the control treatments during June when the photosynthetic rate was near maximum. WPP was found to be correlated with total foliar damage on three dates of damage assessment for non-barrier Empire and for one date Liberty. Tentiform leafminer was the only individual insect damage found to be correlated with WPP. Yield was greater for the barrier plot than the non-barrier plot (0.86 and 0.79 kg.cm-2 TCSA) and greater for Empire than Liberty. No correlation was found between yield and WPP. In light of the interesting results observed in the photosynthesis between the soft chemicals and the conventional chemicals we repeated the study with potted apple trees. We observed similar results to the field experiment with the soft IPM treatments having greater WPP than the conventional IPM control treatments at three sampling dates.
Impacts
Remote sensing infrared thermometry was applied to apple trees to estimate the amount of water stress.
Publications
- Breitkreutz, S.L. and J.A. Flore. 1999. Th effect of simulated stress on the yield and size of Gala and Empire apple. HortScience 34:485 (abstr).
- Reed, M., B. Genter and J.A. Flore. 1999. Reduction in fruit cracking by automatic application of calcium chloride. HortScience 34:489 (abstr).
- Breitkreutz, S.L. and J.A. Flore. 1999. The effect of simulated stress on the yield and size of Gala and Empire apple. 129th Annual Report of the Michigan State Horticultural Sciety (in press).
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Progress 01/01/98 to 12/31/98
Outputs
Carbon C 13 labeled was used to investigate the allocation of carbon and root respiration of apple trees during drought stress. Mildly stressed potted plants were compared with a well watered control over a several day-period. For Budagovsky 9, the lower soil moisture reduced the evolution rate of labeled CO2 from the root, although it did not induce any effects on pre-dawn leaf water potential and single leaf net assimilation rate. Carbon partitioning within the tree was not affected by water supply over the 16-day duration of the experiment. We explained these results as a tree adjustment to the soil condition, which involves a higher fraction of carbon utilized for growth and consequently, a minor fraction of C is assigned to metabolic activities. A decrease in root respiration was the first response of soil water withdrawal even when drought stress was not effective in reducing leaf gas exchange. Recently, we have developed a system of automated intermittent salt
application above the tree during a rain event that has shown very encouraging results (SWMREC annual reports, 1994, 1995, 1996) Washington State Hort Soc. Proc. 1995, Good Fruit Grower, Vol. 47; p23-24, 1996), in Michigan and in the Pacific Northwest. In 1998 we conducted one experiment at Southwest Michigan Research and Extension Center (SWMREC) and several at the Northwest Horticultural Research Station. Results were as follows. 1 We significantly reduced rain cracking with the automated Calcium Chloride application system used in previous years. At SWMREC on Ulster the control averaged 18 % while the .5% Calcium chloride had 6.7% cracks. Similar results were found for Ulster, Somerset, and Rainer at the Northwest Station. Cracking was greater on the upper part of the tree than the lower part for the control. The CaCl2 trees had less cracking on the upper part than the lower part indicating that CaCl2 applied from above the tree was not getting to the lower part of the canopy in
high enough concentrations. Multiple emitters per tree decreased this problem. We determined that there was an interaction with temperature. More fruit cracked at high temperature than low temperature. In the field more cracked during the day than at night even though drying conditions were less favorable. We attribute this to the difference in day and night temperature. Using a bioassay system we able to determine the critical concentration of salt that must be on the fruit to inhibit water uptake and rain splitting up to a four-hour period. That concentration was 0.05-0.10 % depending on the variety and stage of development. Applying a 1.0% solution above the tree at .1mm of rain and continuing it for 4 minutes with a reapplication after 1.0 mm of rain resulted in salt concentrations below the tree of less than 0.1 %. For this size and shape of tree the application rate is almost optimal. Distribution is not uniform enough in the lower parts of the tree.
Impacts
(N/A)
Publications
- Breithkreutz, Sarah, and James Flore. 1998. Whole plant measurement of photosynthesis and development of apple tree in relation to pest damage. HortScience 33:540 (abstr.)
- Giuliani, Rita and James A. Flore. 1998. The effect of water shortage on potted peach trees in relation to ecophysiological parameters and infra-red thermometry. HortScience 33:540.
- Lang, G. C. Guimond, J. A. Flore, S. Southwick, T. Facteau, F. Kappel and A Azarenko. 1998. Performance of calcium/sprinkler-based strategies to reduce sweet cherry rain-cracking. Acta Horticulturae 468:649-656.
- Fernandez R. T. and J. A. Flore. 1998. Intermittent application of CaCl2 to control rain cracking of sweet cherry. Acta Horticulturae 468:683-
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Progress 01/01/97 to 12/31/97
Outputs
The objectives of this research are: 1) to determine foliage damage thresholds for the current growing season based on the assimilation, storage, and translocation of carbon, 2) to determine the carryover effect of foliage damage on carbon storage as it relates to the next season's flowering, fruiting, cold hardiness, and yield for apple and cherry, and 3) to study techniques to reduce cracking of sweet cherry. We developed a series of experiments to determine if using a13CO2 pulse to the foliage could be used to follow the flow of carbon from the shoot to the root and if 13C respiration could be related to either root activity or mass. The evolution of 13C from the root gradually increased and peaked at 100 hours after the pulse. It was directly related to soil temperature. Water stress did not affect root respiration rate. We also investigated the effect of root zone temperature on the kinetics of nitrogen uptake of non- bearing apple trees. The sap exudation rate
was always depressed by low root temperature. The results suggest that root zone temperatures of 8C, although caused a delay (2-4 days) in nitrogen uptake, does not represent a serious limiting factor for N nutrition of tested apple trees on Mark rootstock. We double labeled nitrogen (N15) and carbon (C13) at two different times during the growing season for Empire apples on M-9 rootstock growing in a 1 m x 3 m stainless lysimeter to determine C/N dynamics for an apple tree. Results have not yet been fully processed. An automated low-volume irrigation system to apply CaCl2 intermittently above sweet cherry trees during rain was developed in 1994. The system was tested in orchards in Michigan during the critical fruit cracking periods at the Northwest Michigan Horticultural Research Station in 1997. Prevention of cracking was significant in all application periods over a wide range of fruit maturities for Ulster, Ranier, and Somerset varieties. A bioassay system was developed to
determine what concentrations and forms were effective. Concentrations as low as 0.05 inhibited cracking for up to 4-5 hours. There were no difference due to formulation. Epsom salts were not as effective as calcium chloride. Potted peach trees grown outdoors during the 1997 season were subjected to drought and subsequent rewatering to evaluate their dynamic response to soil water content. The investigation was primarily focused on the early detection of plant water stress to prevent negative effects on the growth. Leaf chlorophyll fluorescence and canopy temperature estimates (by infra-red thermometry) were conducted. drought effects on physiological processes were detected through by estimates of canopy development rate, leaf gas-exchange measurements; while leaf water potential was measured to characterize plants water status. A decrease in the canopy's development rate was found one week after irrigation was stopped, which also coincided with a more negative leaf water potential,
whereas a decrease of the gas- exchange activities occurred several days later.
Impacts
(N/A)
Publications
- HERNANDEZ, RT., PERRY R.L. AND FLORE J.A. 1997. Drought response of young apple trees on three rootstocks. II. Gas exchange, chlorophyll fluorescence, water relations and leaf abscisic acid. J. Amer. Hort. Sci. 122:841-848.
- GAUSSOIN, R.E., BRANHAM, B.E. AND FLORE J.A. 1997. Carbon dioxide exchange rate and chlorophyll content of turfgrasses treated with flurprimidol or mefluidide. J. Plant Growth Regul. 16:73-78.
- FLORE, J.A. AND LAYNE, D. 1997. Photoassimilate production and distribution in stone fruit. HortScience 32: (3) 551 (abstr).
- TOSELLI, M., FLORE, J.A. AND MARANGONI, B. 1997. Effects of root zone temperature on the kinetics of nitrogen uptake of non-bearing apple trees. HortScience 32 (3):519 (abstr).
- LOMBARDINI, L., TOSELLI, M. AND FLORE, J.A. 1997. Use of 13CO2 as tool to investigate carbon partitioning in field and greenhouse-grown apple trees. HortScience 32 (3) :530 (abstr).
- HERNANDEZ, R.T., PERRY, R.L. AND FLORE, J.A. 1997. Drought response of young apple trees on three rootstocks: growth and development. J. Amer. Soc. Hort. Sci. 122:14-19.
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Progress 01/01/96 to 12/30/96
Outputs
The objectives of this research are: 1) to determine foliage damage thresholds for the current growing season based on the assimilation and storage of carbon and 2) to determine the carryover effect of foliage damage on carbon storage as it relates to the next season's flowering, fruiting, cold hardiness and yield for apple and cherry. 3) to study techniques to reduce cracking of sweet cherry. Progress on objectives 1 and 2 was reported on last year, and was similar in 1996. Early season stress had a greater effect on current season fruit quality and yield than later stress and there was a strong interaction with crop load and tree size. Damage thresholds were lower for high crop loads and for trees low in vigor or on dwarf rootstocks. Two methods were evaluated to prevent rain induced cracking of sweet cherries: rain exclusion covers and automatic salt application during rain. The automated salt system was tested in more than 20 different sites and 5 different states
or province. A consortium of growers and researchers met and agreed upon a common protocol for each sites follows: 0.5% calcium chloride; system activated at .1 mm; system run 3-6 min to assure adequate coverage; system reactivated after 1.5mm of rain. In all cases where cracking rains occurred and where the system functioned correctly rain induced cracking was reduced significantly. In Michigan both the automated salt application system and the protective covers provided significant control (50+% vs 10-20%).
Impacts
(N/A)
Publications
- MILLER, D., HOWELL,G., FLORE, J. 1996. Effect of shoot number on potted grapevines:I.Canopy development and morphology. Am. J. Enol. Vitic., 47:244-250.
- MILLER, D.P., HOWELL, G. S., FLORE, J.A. 1996. Effect of shoot number on potted grapevines: II. Dry matter accumulation and partitioning. Am. J. Enol. Vitic., 47:251-256.
- FLORE, J.A. and FERNANDEZ, T. 1995. Cherry cracking: causes and possible solutions. Proc. Wash. State Horticultural Association 91st annual meeting, 311-315.
- FLORE, J.A. 1996. Using video thermal image analysis to monitor stomatal openingin fruit crops. HortScience 31:578-579 (abstract).
- FLORE, J. A., LAYNE, D.R. 1996. Prunus. In photoassimilate distrabution in plantsand crops, source-sink relationships, Zamski, E., Schaffer, A.A. eds. 825-849. Marcel Dekker, Inc. N.Y.
- LOMBARDINI, L., FALUSI, M., CALAMASS, R., FLORE, J.A. 1996. Morpho-physiologicalresponses of Pinus halepensis Mill. Seedlings to drought stress. HortScience 31:576-577 (abstract).
- MILLER, D.P., HOWELL, G. S., FLORE, J.A. 1996. A whole-plant, open, gas-exchange system for measuring net photosynthesis of potted woody plants. HortScience 31:944-946.
- LANG,G. and FLORE, J. 1996. Rain-splitting in cherries: overhead sprinklers. Go.
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Progress 01/01/95 to 12/30/95
Outputs
Damage thresholds for fruit crops. The objectives of this research are: 1)to determine foliage damage thresholds for the current growing season based on the assimilation and storage of carbon and 2)to determine the carryover effect of foliage damage on carbon storage as it relates to the next season's flowering, fruiting, cold hardiness and yield. We investigated this problem using the following techniques: whole plant gas exchange, chlorophyll fluorescence, and simulated damage. We used chemical inhibition of photosynthesis as a tool to investigate the effect of timing and the magnitude of a stress on four different crops (apple, cherry, grape and peach). All showed a reduction of whole tree photosynthesis (50-80% within 24 hr and return to control levels by day 14) by the application of Sinbar, a photosystem II inhibitor. When applied to cherry during Stage I, II or III of fruit growth, or after harvest there was no affect on current or next year's yield, on cold
hardiness, or on return bloom and fruit set. There were significant effects on current season yield for apple and peach. Prevention of rain cracking of sweet cherries. An automated device that changes the osmotic potential of water on the surface of fruit by applying a solution of .05% CaCl2 was successfully tested in Michigan and Washington in 1995. Phytotoxicity occurred when distribution was poor or if the concentration exceeded .1%. Fruit size was reduced in some of the tests.
Impacts
(N/A)
Publications
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Progress 01/01/94 to 12/30/94
Outputs
The objectives of this research are: to determine foliage damage thresholds for the current growing season based on the assimilation and storage of carbon; and to determine the carryover effect of foliage damage on carbon storage as it relates to the next season's flowering, fruiting, cold hardiness, and yield. A series of experiments was initiated to determine mite population and photosynthetic thresholds for sour cherry in containers or under field conditions. Under field conditions significant cumulative mite days were reached obtained after harvest (1750), however there was no reduction in whole tree photosynthesis, current or return yield, or cold hardiness. There was a decrease in leaf chlorophyl level late in the season. Trees in containers were more sensitive. Cumulative mite days (750) reduced leaf and whole tree assimilation, total chlorophyll, over the control trees. We used chemical inhibition of photosynthesis as a tool to investigate the effect of timing
and the magnitude of a stress on four different crops (apple, cherry, grape and peach). All showed a reduction of whole tree photosynthesis (50-80% within 24 hr, and return to control levels by day 14) by the application of Sinbar, a photosystem II inhibitor. When applied to cherry during Stage I, II, or III of fruit growth or after harvest, there was no affect on current or next year's yield on cold hardiness or on return bloom and fruit set. There was significant effects on current season yield for apple and peach.
Impacts
(N/A)
Publications
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Progress 01/01/93 to 12/30/93
Outputs
The question, "what affect does a biological or environmental stress that inhibits photosynthesis (Pn) have on the yield and quality of current and next seasons crop" was addressed for peach, apple and cherry for the 1993 growing season. For all tree crops Pn was inhibited by applying Sinbar (a photosystem II inhibitor) to an entire tree at different times during the season, at two week intervals from two weeks after petal fall until after harvest. Sinbar (60 mg l -1) inhibited Pn (10-20% of control) within 24 hours and recovered to 90- 100% of control 7-14 days after application. Photochemical efficiency, Fv/Fm as measured by chlorophyll fluorescence was inhibited to a greater degree and for a longer period of time than Pn, thus indicating that this technique might be used as an early indicator of stress, prior to a decrease in leaf photosynthesis. Whole tree and single leaf values support this observation. It may be possible then to use a portable fluorescence unit
as an early indication of stress. For peach and apple fruit size, yield and maturity were inversely related to the time of application. The earlier the application the greater the effect on current seasons crop. Cold hardiness of the shoots on peach was reduced sig. by Nov. 30 for all times of inhibition, and fruit set and flower number were reduced the following year. This is assocated with a decrease in storage carbohydrate.
Impacts
(N/A)
Publications
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Progress 01/01/92 to 12/30/92
Outputs
What affect does inhibition of photosynthesis (A) for periods of 7-10 days, during different times during the season (Stage I, II, or III of fruit growth, or after harvest) have on the yield, and quality of the current seasons crop and on winter hardiness and yield the following year for peach "Redhaven". To answer this question photosynthesis was inhibited at the points indicated above by applying 8-12 1 per tree of Sinbar (50mg 1(superscript -1)), which reduced A from 0-25% within 24 hours, A gradually recovered to 80-90% of the controls within 10-14 days. The earlier in the season that A inhibition occurred, the greater the effect on yield, size, and delay in maturity of the current seasons crop and inhibition of vegetative development followed the same pattern. Hardiness of current seasons shoots, storage carbohydrate concentrations, and bloom and fruit set for the next year are being evaluated. A whole plant chamber (3m dia., 4.5 m height) was developed to
measure A of whole trees in the field. Tests indicated that this devise could be used to monitor whole tree photosynthesis and respiration, that temperature build-up in the chamber was no greater than 3-5(degree)C over ambient and that the device could be set up within 30 min., and could stay in place for several days. We will use this system to: a) monitor the effect of mite damage on sour cherry, b) confirm the influence of crop load on whole tree A, c) to determine the effect of the Sinbar treatment on whole plant photosynthesis.
Impacts
(N/A)
Publications
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Progress 01/01/91 to 12/30/91
Outputs
The influence of sink strength on source leaf photosynthesis and of stress on leaf Pn or carbon partitioning was a focal point of our research in 1991. We developed a method to manipulate sink strength and source leaf Pn vegetatively in cherry by defoliation, or continuous light. There was a significant increase in Pn and stomatal conductance due to defoliation within 24 h. Defol. trees had lower daily dark respiration rates. Growth after treatment, SLW (specific leaf weight), leaf chlorophyll and Pn were higher in defol. Following 7 days in continuous light 70% defol. resulted in complete recovery from photosynthetic inhibition. Currently this system is being used to determine the photochemical and biochemical influence of feedback inhibition on cherry, for both the short and long term effect. Under field conditions with plum, fruit removal during stage II of fruit development decreased Pn within 24 h and persisted for 5 days, and was most pronounced in the afternoon.
It was not associated with a more negative leaf water potential. Recovery of Pn, however, was associated with a 5-fold increase in tree vegetative growth. A/Ci curves indicated that the stomatal limitation to Pn was the same for both treatments. There was no significant change in photorespiration. Starch levels in the leaves increased up to 51% in defruited trees 24 h after fruit removal, there were no changes in chlorophyll, fructose, glucose, sucrose or sorbitol levels.
Impacts
(N/A)
Publications
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Progress 01/01/90 to 12/30/90
Outputs
Stress experiments on Kiwi (anoxia), grape, peach and sweet cherry (drought) were conducted to determine the sensitivity of several morphological and physiological parameters to increasing stress, with particular reference to carbon partitioning, photosynthesis, stomatal function, and ABA content of roots, shoots, and the sap (see abstracts and publications below for details). In general leaf and vegetative growth were the first affected, followed by changes in stomatal conductance, then photosynthesis. ABA content of the leaves and roots increased, and in peach where a split root study was conducted, drought not only induced an increase in ABA content, but hydraulic conductivity was also increased. However, root ABA content was lower than in the leaves ranging from 7 pg/g (well watered) to 50 pg/gm for non-watered. We found no evidence to support the contention that under stress conditions, ABA is synthesized in the roots and translocated to the shoots and leaves. The
influence of water stress and crop load on dry matter partitioning was studied in grape. Water stress reduced the total dry matter production, but crop load had no effect and the interaction between the two factors on total dry matter was insignificant after one season of experimentation. Crop load had little effect on root density, however, under water stress root growth was severely reduced with increasing crop load, indicating that there was a definite interaction between the two factors for carbon partitioning.
Impacts
(N/A)
Publications
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Progress 01/01/89 to 12/30/89
Outputs
Several experiments were conducted to determine the influence of water stress (drought and anoxia) on photosynthesis, carbon partitioning, and on hormone content of roots, sap, and leaves of tomato, peach, kiwi, and grape. In addition we continued to investigate the influence of sink strength (both reproductive and vegetative) on source leaf photosynthesis in plum, cherry, and tomato. In strawberry we found that F. chiloensis had significantly higher rates of net CO(2) assimilation than F. X ananassa. Interestingly, F. chiloensis has a lower temp. (18-20) optimum for Pn than F. virginiana (26-30) or F. X ananassa. When grown at 30 day, 20 night or 20 day, 10 night, F. virginiana and F. X ananassa were able to compensate by shifting their temperature of preconditioning while F. chiloensis could not. Experiments on cherry indicated that if leaf area was removed between veins by a paper punch, the remaining tissue would compensate, and the net effect was no loss in carbon
assimilation for the entire leaf. Compensation occurred when up to 20% of the leaf area was removed. A/Ci curves revealed that in compensating leaves, carboxylation efficiency was increased, and that stomatal limitations to assimilation could account for less than 40% of the effect, indicating that control likely resides at the biochemical level.
Impacts
(N/A)
Publications
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Progress 01/01/88 to 12/30/88
Outputs
The effect of fruit sink strength on leaf photosynthetic rate was investigated in plum and cherry. Removal of mature fruits caused an immediate (within 24 hrs) decrease in leaf photosynthesis over 3 growing seasons. The decrease of Pn appeared as early as 24 h after harvest and was particularly evident in the afternoon, or when air temperatures were above 28C and light intensity high. Pn rates of harvested trees remained lower than fruiting ones for 2-3 weeks after removal of fruits. Changes in Pn rate were paralleled by similar, simultaneous changes in stomatal conductance. Stomatal conductance of trees with fruits removed also dimisshed sharply in the pm. Levels of intercellular CO(2) remained approximately constant (190-220 vpm) for both treatments during the course of te experiment. Both stomatal and ntomatal factors seem to be responsible of the observed inhibition of leaf Pn following fruit removal. Stomal contribution to the decrease of Pn ranged from 32
to 40% in a controlled environment and from 25 to 45% under field conditions Both harvested and control treatments showed evidence of O(2)-sensitivity of Pn. The levels of soluble sugars in leaves were not significantly affected by defruiting. In contrast, starch levels in the leaf increased about 3-foild within 48 h after fruit harvest in both years tested. This work supports the hypothesis that defruiting causes end-product inhibition of Pn.
Impacts
(N/A)
Publications
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Progress 01/01/87 to 12/30/87
Outputs
In cold hardiness studies on peach, terminals acclimated first followed by the basal portion of the shoot; this relationship was reversed by late fall. Hardiness was associated with starch content of the shoot, but not with soluble sugar content or water content. Shading for 60 days (80%) starting in July or August reduced carbohydrate content of the shoot and shoot hardiness by 2. Deep winter hardiness was decreased by shading and heavy cropping. We have continued to investigate the control of photosynthesis in fruit crops. Assimilate production in sour cherry and plum seems to be under sink consumption control. Twenty-four hours after removal of fruit Pn decreased to 50% of the non-defruited trees and was associated with an increase in leaf starch content, and was not related to the tree water status which was actually less negative for trees with no fruit. A/Ci curves indicate that most of the inhibition results from internal resistance and not from stomatal
limitations. In the field and in the laboratory, leaves from defruited trees had higher rates of apparent photorespiration as estimated by measuring Pn under 21 or 2% oxygen. In a gas exchange study concerning blueberry fruit photosynthesis, we found that fruit made a positive contribution to their own carbon balance while green, and at temperatures between 15 and 30. Pulsing C0(2) to fruit 30-40 days after development revealed positive uptake of C and export out of the petiole 12 hours after treatment.
Impacts
(N/A)
Publications
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Progress 01/01/86 to 12/30/86
Outputs
Cherry fruit 'Montmorency' harvested at maturity caused trees to appear stressed, as evidenced by a cupping of the leaves. No significant differences in water potential were found due to harvest. However, photosynthesis decreased by 50% of the non-harvested and remained low for 4 weeks. The decrease in Pn was associated with an increase in sorbitol and starch within the leaf, and likely results from a decrease in sink strength. This condition does not occur under high leaf to fruit ratio conditions (4.0 leaves/fruit). Results were similar for peach (Redhaven). Plum (Stanley) was defruited during Stage I, II and III for fruit development. A decrease in Pn was noted during each stage, but recovery was evident after 4-7 days for Stages I and II, and coincided with a resumption of vegetative growth and a decrease in leaf CHO and starch content. We propose that Pn is strongly influenced by sink demand for assimilate, and that a build up of product in the
translocation stream regulates the Pn rate. Sink demand can be either reproductive or in the case for plum, vegetative. High crop load, defoliation and shading experiments on peach decreased winter acclimation to cold temperature. Flooding cherry roots caused a decrease in Pn within 48 hrs. Exudate from flooded cherry tree plants inhibited Pn of leaf explants within 60 min of uptake, and indicate that some translocatable inhibitor of Pn is synthesized during flooding.
Impacts
(N/A)
Publications
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Progress 01/01/85 to 12/30/85
Outputs
Using isotope and carbon balancing techniques, we confirmed that net and gross export in leaves and shoots of sour cherry are initiated at approximately the same stage of physiological development. Photosynthetic rate in the source leaf and direction of transport seem to be controlled in part by the size of the translocation carbon pool. Pn rate is influenced by this pool, which is directly affected by sink strength (either vegetative or reproductive), or can experimentally be affected by shading or defoliation studies. Reproductive sink strength effect on Pn rate was demonstrated in cherry and peach with a portable Pn unit. Fruit photosynthesis was also investigated. For cherry, we found that 11% of the total carbon incorporated could be accounted by fruit photosynthesis alone, and that this figure was considerably higher during stage I (19.4%) and stage II (29.7%) than stage III (1.5%) when red color develops. Genotypic differences in the effect of temperature
on CO(2) assimilation and water use efficiency were noted for Blueberry. Vaccinium darrowi (from a high temp. environment), 'Bluecrop' and 'Jersey' (high-bush cultivars from cooler climates) and an F1 hybrid (US75) were compared. V. darrowii had a higher temp. optimum (30) than Bluecrop (20-22), while the F1 hybrid (30) was similar to V. darrowi. Temperature tolerance may be heritable and may be used to improve the heat tolerance of high-bush blueberry.
Impacts
(N/A)
Publications
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Progress 01/01/84 to 12/30/84
Outputs
Carbon physiology and modeling in large fruit. a) Carbon assimilation, import and export were monitored for the 7th, the oldest, the youngest leaves and fruit for 'Montmorency' sour cherry. Computer similation models were constructed and it was found that the 7th leaf begins to export carbon at 30-35% of full expansion, while the top leaf does not until 70-75% expansion. Net export coincided with gross export. Fruit are capable of photosynthesis, but at no time does fruit Pn compensate for fruit respiration. b) Field defoliation studies indicated that >2.0 leaves per fruit were required for optimum growth and maturation. Fewer leaves delayed ripening, color formation, size increase, and decreased soluble solids. Fruit on spurs, minus leaves, persisted but did not grow or ripen. c) Threshold (leaf to fruit) studies were continued for 'Golden Delicious' apple. From fruit set to 30 days after fruit set shading (20% of full sun) of individual spurs caused a decrease
in fruit size, however shading (40%, 20% of full sun) or defoliation (15-30%) 30 days after set did not have an effect on fruit size, soluble solids, or firmness. Carbon physiology in small fruit. Highbush blueberries have lower temperature thresholds for photosynthesis than V. darrowii, a native of drier, hotter climates. Crosses between V. darrowii and 'Bluecrop' are more heat tolerant than 'Bluecrop', and have greater water use efficiency.
Impacts
(N/A)
Publications
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Progress 01/01/83 to 12/30/83
Outputs
Carbon assimilation and Translocation. In sour cherry (Prunus cerasus) both sorbitol and sucrose were isolated from mature leaves, and studies are in progress to identify the main translocatable sugar. Using PG,CO(2) major translocation patterns for carbon have been established. Summer tipping 45-50 days after bloom, caused a greater incorporation of assimilated carbon from shoot leaves into developing fruit, than non-tipped shoots. Leaf to fruit ratios were further investigated to determine the minimum number of leaves needed to mature and size a cherry fruit. 1983 data confirmed that of 1982, which indicated that 1.5 leaves or 30cmy leaf area are minimum to maintain growth. For peach (prunus persica) the effect of light on fruit maturity and coloration was investigated. A minimum of 4 days of full sun during stage III are needed to produce acceptable red color for harvest. Stomatal control. The effect of CO(2) and vapor pressure gradient (VPG) on stomata
response of apple, cherry and blueberry were investigated. Stomata began to close when VPG reached 1.5kpa for all three species. All three were very sensitive to VPG. If a slight water stress was imposed, then stomatal sensitivity to CO(2) was increased. The sensitivity to CO(2) concn. decreased after rewatering, but there was a 1-3 day lag period. Water stress.
Impacts
(N/A)
Publications
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Progress 01/01/82 to 12/30/82
Outputs
Carbon assimilation in apple and cherry. In apple we established that defoliation had a significant effect on Pn when 20% of the leaf area was removed, but not at 10% removal. In greenhouse and field experiments, the effect of 10, 20, or 30% removal either from individual leaves or from removing whole leaves on dry matter production was investigated. No significant reduction in dry matter was noted until 20% of the leaf area was removed. This would indicate that the remaining leaf area compensates for the loss of leaf area. In cherry a graphic model of shoot and fruit growth was developed from leaf emergence, leaf expansion, and fruit development programs. The model can be used for instruction or for research to determine the effect of one or more than one factors on growth. Leaf to fruit ratios were investigated to determine the minimum number of leaves needed to mature and size a cherry fruit. 1982 data would indicate that 1.5 leaves or greater than 30 cm. 2
leaf area minimum to maintain growth. Water stress. The effect of temperature and vapor pressure deficit (VPD) on photosynthesis (Pn), transpiration (TR) and water use efficiency (WUE) was investigated. As temp increases, Pn decreased from a maximum of 15 degrees C. Stomatal apeture is influenced by VPD above 1.5 KPa. Stomata are responsive to CO(2) concn. until 1000 ppm. is obtained.
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Progress 01/01/81 to 12/30/81
Outputs
In apple, established that intravenal defoliation had a significant effect on Pnwhen 20% of the leaf area was removed. There was synergistic effect on Pn until the 20% level of damage was reached. When damage occurred across veins, there was a significant reduction in Pn rate expressed on a whole leaf basis or unit area basis. Several studies conducted in 1980 and 1981 indicated the photosynthetic rate per leaf was not significantly inhibited until a damage threshold of 3-4 mines/leaf was reached, which approximately equaled 10% of the individual leaf area. Data for the whole tree model was collected and is being processed. Field plots were established at the Traverse City Station for trickle irrigation scheduling experiments. Several plant factors were correlated with water stress in stone fruit. Of these, fluctuation in trunk diameter seems to be a good indicator of water stress in plants. An instrument for field use has been constructed and will be evaluated
in the field this Summer. Stomatal opening and closing is affected by light and UPD, more than internal water potential in cherry and peach. Partitioning - Decapitation of cherry shoots had a significant effect on Pn, Rs and Tr. In general, senescence was delayed and Pn continued at a high rate for a longer period of time than non-cut controls. Summer hedging had a dramatic effect on the dry matter partitioning in Redhaven Peach, root shoot ratios were decreased, and total growth was inhibited.
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Progress 01/01/80 to 12/30/80
Outputs
Light levels were determined at four different times during the growing season, with the use of hemispherical photography, in four peach hedgerow canopies. Greatest percent sky levels occurred in the area from the top of the canopy to 25 cm below the top. On a given date there was very little difference between canopy training systems except at the 1 m level. Hedging canopies improved the light microclimate in the outer 25 cm only. Shade reduced average stem diameter but increased average leaf area. Specific leaf weight and photosynthetic rate decreased as light decreased. Chlorophyll content per unit leaf area increased as light decreased but stomatal resistance was unaffected. For sour cherry, there were no significant dirunal changes in photosynthesis (Pn) for individual leaves. Seasonal patterns for Pn varied, but in general Pn reached a peak early in the season as leaves expanded, remained stable for several weeks, then gradually declined. There was no
significant effect of fruit on average seasonal Pn.
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Progress 01/01/79 to 12/30/79
Outputs
Using fisheye photography and conventional light measuring techniques, we have characterized light distribution (quantitative and qualitative) in cherry and peach tree canopies, when grown using different training systems and orchard designs. Canopy development in cherry can be predicted on the basis of heat units accumulated. It is rapid and is complete for spurs and terminals in 20-25 days and 55-60 days from bloom, respectively. Artificial shading studies and field correlation data indicates that 20-25% sky values are needed for flower bud initiation. Shading decreased leaf thickness and photosynthetic rate at light saturation, but increased leaf area and terminal growth. Shading (greater than 80%) significantly decreased wood and bud hardiness of sour cherry and peach. The effect of environment on photosynthetic rate for sour cherry leaves has been determined. Optimum rates were found at temp between 20-25 degrees, with light saturation occuring at
approximately 35-45% of full sunlight. Pn rate declined (from 40 to less than mgCO(2)dm - 2hr - 1) after full leaf expansion through the season, was positively affected by the presence of fruit, and decreased after solar noon. Spur-type clones had higher rates of Pn than non-spur types. A technique was developed to root softwood cuttings of sour cherry and peach to determine if they can be grown on their own root under Michigan conditions.
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Progress 01/01/78 to 12/30/78
Outputs
Pn values for sour cherry (Prunuscerasus L.) are highest during periods of greatest leaf expansion and fruit growth, which occurs early in the season (40 mg CO(2) dm - 2 hr - 1) declines and then remains constant (20-25 mg CO(2) dm - 2 hr - 1) near the end of the growing season. Newly expanded leaves have higher Pn rates than mature leaves, and leaves adjacent to fruit assimilate carbon at higher rates than leaves farther removed from fruit during periods of rapid fruit growth (Stage I and III). Diurnal fluctuations for individual leaves exist. If placed under constant environmental conditions Pn rates increase to a maximum just prior to solar noon, remain constant for 1-3 hours, then decline to 80% of maximum 6 to 8 hours later. Optimum environmental conditions for Pn vary depending upon the location, and age of the leaf tissue within the tree. In general, for healthy leaves grown in the sun, temperatures of 25-30 degrees C, and light of 1000-1200 MuE m - 2s - 1
are optimum. However, leaves grown in the shade have much lower light saturation points which depend upon the amount of shade that they were grown under. Differences in Pn have been detected in mutant clones from "Montmorency" sour cherry. Precocious and spur type one year-old trees seem to have greater Pn rates than "Montmorency" when compared under similar conditions. Tree canopy development and microclimate are being investigated using conventional light measuring devices and by hemispherical photography.
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Progress 01/01/77 to 12/30/77
Outputs
An open gas analysis system has been developed to quantify the influence that environmental variables have on photosynthetic efficiency. Preliminary determinations indicate that stone fruit differ widely in their ability to assimilate CO(2), with apricot being one of the highest and sour cherry one of the lowest. In addition a device designed to pulse radioactive CPG,0(2) to leaves, which will simultaneously measure temperature, stomatal resistance and PAR active light has been developed to measure photosynthetic efficiency and partitioning of assimilate under field conditions. Cherry tree canopy development and light distribution within the canopy are being investigated using conventional light measuring equipment and by hemispherical photography. For sour cherry canopy development is initially very rapid, which greatly reduces light reaching the interior of the tree. Cultural practices (pruning, planting distance, etc.) greatly influence both light quantity and
quality. The physiological basis for fruit russeting has been investigated by observing cuticle, and cell development of several different Golden Delicious apple clones grown in Michigan and Washington. Preliminary results indicate that no positive correlation exists between degree of russet at harvest and cuticle thickness or wax deposition on a per surface unit basis. Several compounds have been screened to test their anit-russeting properties.
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