Source: MICHIGAN STATE UNIV submitted to NRP
LIGHTING OF SPECIALTY CROPS IN CONTROLLED ENVIRONMENTS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1012321
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
May 1, 2017
Project End Date
Apr 30, 2022
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
MICHIGAN STATE UNIV
(N/A)
EAST LANSING,MI 48824
Performing Department
Horticulture
Non Technical Summary
In temperate climates, environmental variables such as light and temperature change throughout the season, even in controlled-environment greenhouses. Despite environmental controls, seasonal variation in climate leads to seasonal variation in plants produced. Growers are interested in producing high-value specialty crops, such as floriculture and vegetable transplants, in completely enclosed growing systems to produce much more uniform crops. Similarly, leafy greens and herbs (e.g., lettuce, basil, and spinach) are increasingly being grown locally indoors for more consistent crop quality attributes including freshness, texture, and color. However, there are several barriers to profitable indoor production of high-value ornamental and edible crops including management of the growing environment. This project focuses on manipulating the light spectrum to produce specialty crops with desired and specific crop characterists, which could include compactness, a desired leaf shape or size, leaf coloration, nutritional content, and early or late flowering. Research-based information will be generated and then disseminated to grower and academic groups that advances the science and application of greenhouse and indoor plant lighting.
Animal Health Component
80%
Research Effort Categories
Basic
0%
Applied
80%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2042123102025%
2041430102025%
2052123102015%
2051430102015%
5021430102010%
5112123102010%
Knowledge Area
511 - New and Improved Non-Food Products and Processes; 204 - Plant Product Quality and Utility (Preharvest); 205 - Plant Management Systems; 502 - New and Improved Food Products;

Subject Of Investigation
1430 - Greens and leafy vegetables; 2123 - Bedding/garden plants;

Field Of Science
1020 - Physiology;
Goals / Objectives
To characterize and quantify how a variety of floriculture crops (including popular bedding plants and herbaceous perennials) respond to the addition of far-red light to a blue+red spectrum and then categorize them into response groups.To learn how different intensities of blue light and the total photosynthetic photon flux (PPF) interact with far-red light to regulate growth and subsequent flowering of floriculture crops.To determine how far-red, blue, and UV-A radiation can be delivered during different transplant production stages to regulate growth and increase quality of floriculture crops and specialty leafy greens.To determine how light quality and quantity interact to affect growth attributes of leafy greens grown in controlled environments.To examine whether UV-A-mediated regulation of coloration and nutrition of leafy greens interacts with far-red-mediated regulation of shade-avoidance responsesTo evaluate how lighting treatments influence consumer sensory attributes and preferences including taste, texture, and appearance of leafy greens.
Project Methods
A variety of floriculture crops will be chosen for study based on commercial significance, shade tolerance, and photoperiodic flowering characteristics. Seeds will be sown in 128-cell plug trays by a commercial young plant producer and obtained after germination. Cuttings will be grown in a propagation greenhouse until they have root initials (after 5-8 days), and then transferred to the lighting treatments. Plants will be grown in six customized LED growth modules located in a refrigerated walk-in growth chamber set at 20 °C. Inside each growth module, LEDs will operate with an 18-hour photoperiod to deliver the lighting treatments. In each treatment, blue and red light will be fixed at 32 and 128 µmol/m-2s-1, respectively, and far red (FR) light will be added at 0 to 128 µmol/m-2s-1. A variety of appropriate sensors (e.g., thermocouples, infrared sensors, and quantum sensors) will measure environmental parameters and data will be recorded by a datalogger. Irrigation and fertility will follow established MSU Floriculture research protocols for young plants. At the end of the transplant stage, plants from each treatment will be transplanted into 10-cm pots and grown in a common greenhouse finishing environment at 20 °C. Supplemental lighting will be provided during the 16-hour photoperiod by high-pressure sodium lamps. Data will be collected at the end of the transplant stage (3 to 5 weeks of treatments) and at flowering. At the end of the transplant stage, the following data will be collected: leaf number on the primary stem, total leaf area, stem length, and dry weight of shoots and roots. During the finishing stage, date of first flowering, flower bud or inflorescence number, and length of the primary stem at first flowering will be recorded. Here and below, plant data will be pooled from two experimental replications and analyzed in SAS using the PROC-MIXED and PROC-GLM procedures in the Tukey's HSD test.Based on results from the experiment above, six representative species of young plants will be selected and grown under six LED treatments at the same photosynthetic photon flux density (PPFD) but with different mixtures of red, blue, and FR light. The FR radiation intensities may be adjusted based on the previous experiment. All other aspects of the experimental protocol will be as described above. An additional, subsequent experiment will be performed at two PPFDs and with two ratios of red and FR, to be determined based on the results.Based on results from the experiments described above, at least six representative species of young plants will be grown under at least eight LED treatments that include UV-A, blue, red, and/or FR light. All other aspects of the experiment will be as described in #1 above, but with two exceptions: we will use the Controlled-Environment Lighitng Laboratory (CELL) at MSU and the light spectrum may change during the second half of the transplant production phase to elicit stage-specific plant responses.Green and red leaf lettuce, spinach, and arugula will be grown in CELL at 20 °C using a multi-factorial, completely randomized block design under four light qualities (consisting of UV-A, blue, red, and FR), two photoperiods (16 or 24 h), and two PPFDs during three production stages: lag, exponential, and finish. For comparison, the same cultivars will be grown in a greenhouse under a 16-h or 24-h photoperiod at 20 °C with similar photosynthetic daily light integrals achieved using supplemental lighting from blue+red LEDs or high-pressure sodium lamps. At the end of the finish phase, plants will be measured to determine biomass accumulation, leaf area and thickness, and leaf color indices as well as concentrations of several compounds (chlorophyll, flavonoids, etc.)The same crops will be grown in CELL with three levels of UV-A radiation, two levels of FR, and a PPFD of 200 µmol/m-2s-1 from white or blue+red LEDs. Plants will receive only white or blue+red during the first two weeks before the onset of UV-A and FR treatments. In addition, we will deliver supplemental FR during the exponential phase and supplemental UV-A during the finish phase to test the viability of dynamic lighting. At harvest, we will collect the same data as in #4 above.Sensory analysis will evaluate overall consumer acceptance and sensory attributes (i.e., appearance, texture, and flavor) of lettuce samples grown under some of the different CELL and greenhouse treatments. Subjects who regularly consume lettuce will be recruited and compensated for each sensory test. Test samples will be presented, and each participant will be asked to rate the appearance, texture, flavor, overall acceptanc, and purchase intent. After the sample-related questions, participants will be asked demographic questions. Data will be analyzed using XLSTAT to summarize the statistical significance of positive and negative consumer perceptions of the lettuce samples.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:• Commercial greenhouse growers, especially those who propagate plants • Entrepreneurs developing vertical farm businesses to produce high-value specialty crops • Indoor producers of leafy greens and herbs • Plant lighting professionals, growth chamber manufacturers, and allied trades • Academic and institutional peers Changes/Problems:Most of our research was terminated in late March, 2020 due to the pandemic. Research activity has since ramped up but overall, progress was delayed by approximately 3 months. What opportunities for training and professional development has the project provided?Two Ph.D. graduate students were mentored in this project this year, and one post-doctoral scholar also participated. Project team members (including graduate students) participated in a USDA-affiliated regional research meeting (NCERA-101) and scientific conferences, including the the American Society for Horticultural Science annual conference. They also participated in the annual meeting of the Floriculture Research Alliance, which is a stakeholder network of leading producers of specialty crops grown in controlled environments. How have the results been disseminated to communities of interest?We have published numerous research-based articles for grower trade magazines with national circulation. Information was also shared at different academic and inudstry meetings throughout the U.S. as well as in the Netherlands and the United Kingdom (see other accomplishments). More information about our outreach activities as they relate to this project can be found online at https://www.canr.msu.edu/profiles/dr_erik_runkle/cell. What do you plan to do during the next reporting period to accomplish the goals?Research and outreach activities continue to address our stated objectives. Experiments focused on optimization of the lighting spectrum are planned with seedling ornamental crops and leafy greens grown indoors. We are also performed greenhouse experiments that focus on spectral manipulations to increase yield of leafy greens and potentially other high-value specialty crops. Additional scientific and grower publications are being planned for publication in 2020-2021.

Impacts
What was accomplished under these goals? We quantified growth responses and subsequent flowering of annual bedding plant seedlings grown indoors under sole-source lighting. Seedlings were grown under combinations of blue (B; 400−500 nm), red (R; 600−700 nm), and far-red (FR; 700−800 nm) light with 20 or 60 μmol m-2 s-1 of blue, 120 or 160μmol m-2 s-1 of red, and 0, 10, 20, or 40μmol m-2 s-1 of far-red light. Seedlings were also grown indoors under warm-white (WW180) LEDs or in a greenhouse for comparison. Among all nine species tested, the addition of far red light at 40 μmol m-2 s-1 increased the seedling height of only snapdragon (by 64-134%) and zinnia (by 52-96%), regardless of the proportion of blue light, compared with lighting treatments without far-red light or in the greenhouse. Similarly, warm-white light promoted seedling stem elongation in snapdragon (by 75-139%) compared with blue+red light without far red or the greenhouse control, but not in the other species. Lighting treatments did not influence leaf area and dry shoot weight in any species. The subsequent flowering of snapdragon was accelerated by 7-11 days with the additional 20 or 40 μmol m-2 s-1 of far red, or under warm-white LEDs, compared with lighting without far red or the greenhouse control. We conclude that when ≥20 μmol m-2 s-1 of blue light is delivered to crops, the addition of far red at ≥20 μmol m-2 s-1 can accelerate flowering of at least some long-day plants, with little to no effect on extension growth, but has no effect on flowering of day-neutral or short-day plants. In another series of experiments, we investigated how far-red light interacted with the ratio of blue to red light (B:R) (experiment I) and light intensity (experiment II) to regulate seedling growth under sole-source lighting. In experiment I, lettuce 'Rex' and 'Cherokee' and basil 'Genovese' were lighted continuously at 180 μmol m-2 s-1 by blue and/or red light at four different ratios, 1:0, 1:5, 1:1, or 0:1, with or without 30 μmol m-2 s-1 of far-red light. The addition of far-red light increased leaf length and shoot weight of all crops with more pronounced impacts under high B:R than low B:R. It also increased root dry weight of basil and lettuce 'Cherokee'. Red pigmentation of lettuce 'Cherokee' increased with increasing B:R but decreased with the inclusion of far-red light. In experiment II, we grew lettuce 'Rex' and 'Rouxai' under 180 or 360 μmol m-2 s-1 at equal parts of blue and red, with or without far-red light at 30 or 75 μmol m-2 s-1. The additional far-red light increased lettuce shoot weight and extension growth but reduced leaf greenness under both light intensities, although far red effects were attenuated under the higher light intensity. Shoot dry weight and red foliage pigmentation increased with light intensity. We conclude that far-red light enrichment improves photosynthetic radiation capture and thus promotes crop growth under sole-source lighting, and that its effects are especially pronounced under high B:R and a low light intensity.

Publications

  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Kelly, N., D. Choe, Q. Meng, and E.S. Runkle. 2020. Promotion of lettuce growth under an increasing daily light integral depends on the combination of the photosynthetic photon flux density and photoperiod. Sci. Hort. (article 109565).
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Park, Y. and E.S. Runkle. 2019. Blue radiation attenuates the effects of the red to far-red ratio on extension growth but not on flowering. Environ. Exp. Bot. 168 (article 103871).
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Runkle, E.S., Q. Meng, and Y. Park. 2019. LED applications in greenhouse and indoor production of horticultural crops. Acta Hort. 1263:17-30.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Runkle, E.S. 2019. Environmental control of the flowering process of Phalaenopsis orchids. Acta Hort. 1262:7-12.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhang, M., Y. Park, and E.S. Runkle. 2020. Regulation of extension growth and flowering of seedlings by blue radiation and the red to far-red ratio of sole-source lighting. Sci. Hort. (article 109478).
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Lopez, R.G., Q. Meng, and E.S. Runkle. 2020. Blue radiation signals and saturates photoperiodic flowering of several long-day plants at crop-specific photon flux densities. Sci. Hort. (article 109470).
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Meng, Q., J. Boldt, and E.S. Runkle. 2020. Blue radiation interacts with green radiation to influence growth and predominantly controls quality attributes of lettuce. J. Amer. Soc. Hort. Sci. 145:75-87.
  • Type: Other Status: Published Year Published: 2020 Citation: Runkle, E. 2020. How to produce poor-quality floriculture crops. Greenhouse Product News 30(9):50.
  • Type: Other Status: Published Year Published: 2020 Citation: Runkle, E. 2020. Indoor propagation. Greenhouse Product News 30(7):42.
  • Type: Other Status: Published Year Published: 2020 Citation: Runkle, E. 2020. UV-transmitting greenhouse glazing. Greenhouse Product News 30(6):42.
  • Type: Other Status: Published Year Published: 2020 Citation: Runkle, E. 2020. What is the ideal lighting spectrum? Greenhouse Product News 30(3):42.
  • Type: Other Status: Published Year Published: 2020 Citation: Runkle, E. 2020. The perils of low (greenhouse) temperature. Greenhouse Product News 30(2):42.
  • Type: Other Status: Published Year Published: 2020 Citation: Runkle, E. 2020. LED fixture efficacy: A 2020 update. Greenhouse Product News 30(1):50.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. How much supplemental lighting do you need? Greenhouse Product News 29(12):42.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. Propagation pointers. Greenhouse Product News 29(11):42.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. Greenhouse environment checklist. Greenhouse Product News 29(10):50.


Progress 10/01/18 to 09/30/19

Outputs
Target Audience: Commercial greenhouse growers, especially those who produce floriculture propagules Entrepreneurs developing vertical farm businesses to produce high-value specialty crops Indoor producers of leafy greens and herbs Plant lighting professionals, growth chamber manufacturers, and allied companies Academic and institutional peers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One Ph.D. graduate student and one M.S. student were mentored in this project this year, and one post-doctoral assistant also participated. The Ph.D. student graduated in 2018. Project team members (including graduate students) participated in a USDA-affiliated regional research meeting (NCERA-101) and scientific conferences, including the the American Society for Horticultural Science annual conference. They also participated in the annual meeting of the Floriculture Research Alliance, which is a stakeholder network of leading commercial greenhouse (and sometimes indoor) growers. How have the results been disseminated to communities of interest?We have published numerous articles for grower trade magazines (with national circulation) based on our research results. Information was also shared at different academic and inudstry meetings in Florida, Michigan, Minnesota, Nevada, New York, and Oregon, as well as in France, the United Kingdom, Turkey, and South Korea. Articles about our indoor lighting research have been published in several different media outlets including magazines, TV interviews, and science fairs oriented for diverse audiences. More information about our outreach activities as they relate to this project can be found online at https://www.canr.msu.edu/profiles/dr_erik_runkle/cell. What do you plan to do during the next reporting period to accomplish the goals?Research and outreach activities continue to address our stated objectives. We have also received funding from NIFA to increase our research and outreach activities as they relate to indoor production of leafy greens. This project, funded in part by the Specialty Crops Research Initiative, is in collaboration with academics at Michigan State University, Ohio State University, Purdue University, and the University of Arizona, as well as a large stakeholder focused on indoor production. Additional scientific and grower publications are being planned for publication in 2019-2020.

Impacts
What was accomplished under these goals? There are many compelling reasons to produce both ornamentals and high-value specialty crops indoors, in controlled environments. For example, yields are substantially higher, inputs such as water and fertilizer are dramatically reduced, crops can be grown year-round and are not subject to weather extremes, and production can be located near urban areas. However, there are several barriers to profitabilty in the indoor production of crops such as leafy greens and floriculture transplants, especially the cost to purchase and operate electric lighting. Our research focuses on reducing the electricy costs for indoor production while also increasing the quality attributes of leafy greens and floriculture propagules. Adding green light to blue and red light creates white light, which is a more desirable spectrum for people working in indoor farms. Although green light can drive photosynthesis and regulate plant growth, its effects have been inconsistent. We grew red-leaf lettuce 'Rouxai' in a temperature-controlled growth room under nine sole-source light-emitting diode (LED) treatments with a 20-hour photoperiod or in a greenhouse. At the same total light intensity (400-800 nm) of 180 µmol m-2 s-1, we grew plants under warm-white LEDs or increasing blue light intensities at 0, 20, 60, and 100 µmol m-2 s-1 with or without substituting the remaining red light with 60 µmol m-2 s-1 of green light. Biomass and leaf expansion negatively correlated with the blue photon flux density with or without greenlight. For example, increasing blue light decreased fresh and dry mass by up to 63% and 54%, respectively. The inclusion of green light did not affect shoot dry mass at 0 or 20 µmol m-2 s-1 of blue light, but decreased it at 60 or 100 µmol m-2 s-1 of blue light. Results suggest shade-avoidance responses are strongly elicited by low blue light and repressed by high blue light. Green light barely influenced morphology, foliage coloration, essential nutrients, or sensory attributes, regardless of the blue light intensity. Increasing blue light increased red foliage coloration and concentrations of several macronutrients (e.g., nitrogen and magnesium) and micronutrients (e.g., zinc and copper). Consumers preferred plants grown under sole-source lighting to those grown in the greenhouse, which were more bitter and less acceptable, flavorful, and sweet. We conclude lettuce morphology is primarily controlled by blue light, and green light maintains or suppresses lettuce growth, depending on the blue light intensity. Including far-red light in indoor lighting can promote seedling growth and, in at least some long-day plants, can accelerate subsequent flowering. Here we investigated how the duration and timing of far-red treatments during the seedling stage influence growth and subsequent flowering of common floriculture transplants. Seedlings of dianthus, geranium, petunia, and snapdragon were grown at 20 °C under an 18-hour photoperiod with a light intensity of 32 µmol m-2 s-1 of blue and 128 µmol m-2 s-1 of red. The 27 day seedling stage was divided into three equal phases, and 32 µmol m-2 s-1 of far-red light was provided for one-third, two-thirds, or the entire seedling stage. Seedlings were then transplanted and grown in a common greenhouse environment until flowering at 20 °C with a 16-hour photoperiod. Generally, plant height increased (by 20 to 86%) as the duration of exposure to far-red increased, and as the timing of far-red light was delayed. However, there was little to no effect of far-red treatment on leaf number and total leaf area in any species. In snapdragon and petunia, the greenness of leaves decreased when far-red was delivered during the first and third phases, the last two phases, or the entire seedling stage. In petunia, 9 days of far-red during the second or third seedling phase also reduced leaf greenness. Compared to without far red light, shoot dry weight increased when far-red was delivered during the entire seedling stage for petunia (by 60%), or during the last two phases for geranium (by 32%).

Publications

  • Type: Theses/Dissertations Status: Published Year Published: 2018 Citation: Meng, Q. 2018. Improving yield and quality of indoor food crops with precise light regimens. PhD diss., Dept. of Hort., Mich. State Univ., East Lansing, MI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Park, Y. and E.S. Runkle. 2018. Investigating the interaction between photosynthetic photon flux density and far-red radiation in petunia seedlings under sole-source lighting. Acta Hortic. 1227:541-548.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Meng, Q. and E.S. Runkle. 2018. Using radiation to enhance quality attributes of leafy vegetables: A mini-review. Acta Hortic. 1227:571-578.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Lindberg, H.M., R.A. Cloyd, and E.S. Runkle. 2018. Floriculture College of Knowledge online course series: Demographics and impact. J. Natl. Assoc. County Agr. Agents 11(2).
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Meng, Q. and E.S. Runkle. 2019. Regulation of flowering by green light depends on its photon flux density and involves cryptochrome. Physiol. Plant. 166:762-771.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhang, M. and E.S. Runkle. 2019. Regulating flowering and extension growth of poinsettia using red and far-red light-emitting diodes for end-of-day lighting. HortScience 54:323-327.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Meng, Q., N. Kelly, and E.S. Runkle. 2019. Substituting green or far-red radiation for blue radiation induces shade avoidance and promotes growth in lettuce and kale. Environ. Exp. Bot. 162:383-391.
  • Type: Other Status: Published Year Published: 2019 Citation: Meng, Q. and E. Runkle. 2019. How green light affects floriculture crops. Greenhouse Grower 37(2):26-28.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E., Y. Park, M. Zhang, and P. Fisher. 2019. Lighting young plants indoors. GrowerTalks 82(10):58-60.
  • Type: Other Status: Published Year Published: 2019 Citation: Meng, Q. and E. Runkle. 2019. Green & far red LED lighting. Produce Grower (Feb.):22-25.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. Selecting an LED fixture. Greenhouse Product News 29(2):42.
  • Type: Other Status: Published Year Published: 2019 Citation: Park, Y. and E. Runkle. 2019. LEDs: Far red & light intensity interaction. GrowerTalks 82(11):54-57.
  • Type: Other Status: Published Year Published: 2019 Citation: Meng, Q. and E. Runkle. 2019. Green and blue LED lighting. Produce Grower (Mar.):20-24.
  • Type: Other Status: Published Year Published: 2019 Citation: Park, Y. and E. Runkle. 2019. LEDs: Blue & far-red light. GrowerTalks 82(12):58-60.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. Crops suitable for indoor farming. Greenhouse Product News 29(4):42.
  • Type: Other Status: Published Year Published: 2019 Citation: Zhang, M., Y. Park, and E. Runkle. 2019. A little far-red light goes a long way. GrowerTalks 83(1):58-61.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. DLI requirements. Greenhouse Product News 29(5):50.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhang, M., C.W. Whitman, and E.S. Runkle. 2019. Manipulating growth, color, and taste attributes of fresh cut lettuce by greenhouse supplemental lighting. Sci. Hort. 252:274-282.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Meng, Q. and E.S. Runkle. 2019. Far-red radiation interacts with relative and absolute blue and red photon flux densities to regulate growth, morphology, and pigmentation of lettuce and basil seedlings. Sci. Hort. 255:269-280.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. and J. Faust. 2018. New, high-resolution, interactive DLI maps. Greenhouse Product News 28(10):46.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. White LEDs for plant applications. Greenhouse Product News 28(11):42.
  • Type: Other Status: Published Year Published: 2018 Citation: Park, Y. and E. Runkle. 2018. Growing ornamental seedlings under white LEDs. Greenhouse Grower 36(11):23-26.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. DLC requirements for LED fixtures. Greenhouse Product News 28(12):42.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. Is green light useful to plants? Greenhouse Product News 29(6):50.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. An overview of long-day lighting. Greenhouse Product News 29(7):58.
  • Type: Other Status: Published Year Published: 2019 Citation: Runkle, E. 2019. Including far red in an LED lighting spectrum. Greenhouse Product News 29(9):58.


Progress 10/01/17 to 09/30/18

Outputs
Target Audience:• Commercial greenhouse growers, especially those who produce floriculture propagules • Entrepreneurs developing vertical farm businesses to produce high-value specialty crops • Indoor (vertical farm) producers of leafy greens and herbs • Plant lighting professionals, growth chamber manufacturers, and allied companies • Academic and institutional peers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two Ph.D. graduate students and one M.S. student have been mentored in this project. One Ph.D. student and the M.S. student graduated in 2018. Project team members (including graduate students) participated in USDA-affiliated regional research meetings (NCERA-101) and scientific converences, including the the American Society for Horticultural Science annual conference and the annual meeting of the Floriculture Research Alliance. How have the results been disseminated to communities of interest?We have published several articles for grower trade magazines based on our research results. Information was also shared at different academic and inudstry meetings in Michigan, Illinois, North Carolina, Washington D.C., as well as China and South Korea. Articles about our indoor lighting research have been published in several different media outlets including magazines, TV interviews, and science fairs oriented for diverse audiences. What do you plan to do during the next reporting period to accomplish the goals?Research and outreach activities continue to address our stated objectives. Funding from different granting agencies is being sought to expand the scope and scale of this project. Additional scientific and grower publications are being planned for publication in 2019.

Impacts
What was accomplished under these goals? There are several barriers to profitabilty in the production of high-value ornamental and edible crops (such as leafy greens) when grown indoors. The major input costs are typically 1) electricity for lighting and heating/air conditioning, 2) labor, and 3) depreciation of the facility. Our research focuses on reducing the electricy costs for indoor production, while also increasing the quality attributes of leafy greens and florinculture propagules. A series of experiments was performed to understand how blue light and far-red light interact to regulate growth of floriculture crop seedlings. We grew seedlings of geranium, petunia, and coleus in a controlled growth chamber under six sole-source LED lighting treatments with an 18-hour photoperiod. All treatments provided photosynthetic light at 160 µmol/m2s1 with the following intensities (subscript in µmol/m2s) of blue (B), red (R), or/and far-red (FR) radiation: B80R80, B80R80FR10, B80R80FR80, R160, R160FR20, and R160FR160. When seedlings were sufficiently large, they were transplanted into 4-inch pots and subsequently grown in a common greenhouse finishing environment. As expected, stem length of all species increased linearly with additions of FR. Under R+B light, stem length of petunia and geranium also increased linearly with additional FR, but substantially less (55-85%) than under red light alone. In coleus, there was little to no effect of FR on stem elongation under B+R light. In petunia, the addition of FR promoted subsequent flowering by 7 to 11 d. In day-neutral geranium, plants grown under R160FR160 flowered earlier than those grown under B80R80. We conclude that a moderately high intensity of blue light attenuates the effects of FR radiation on extension growth, but has no apparent effect on the FR-promotion of flowering promotion. Based on this information, a spectrum that includes a moderately high intensity of blue light, plus at least some far-red light, can produce floriculture seedlings with many of the desired attributes. Additional research is needed on other wavebands of light, and how they interact with one another, as well as other environmental parameters such as temperature.

Publications

  • Type: Theses/Dissertations Status: Published Year Published: 2018 Citation: Zhang, M. 2018.Manipulating light quality to improve growth attributes of high-value specialty crops in controlled environments. MS thesis, Dept. of Hort., Mich. State Univ., East Lansing, MI.
  • Type: Theses/Dissertations Status: Published Year Published: 2018 Citation: Park, Y. 2018. Controlling the radiation spectrum of sole-source lighting to elicit desirable photomorphogenic traits and regulate flowering of floriculture seedlings. PhD diss., Dept. of Hort., Mich. State Univ., East Lansing, MI.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Poel, B.R. and E.S. Runkle. 2017. Spectral effects of supplemental greenhouse radiation on growth and flowering of annual bedding plants and vegetable transplants. HortScience 52:1221-1228.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: 4. Llera, J.R., E.D. Goodman, E.S. Runkle, and L. Xu. 2018. Improving greenhouse environmental control using crop-model-driven multi-objective optimization. GECCO '18 Proc. Genet. Evolution Computation Conf. Companion 292-293.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Park, Y. and E.S. Runkle. 2018. Far-red radiation and photosynthetic photon flux density independently regulate seedling growth but interactively regulate flowering. Environ. Exp. Bot. 155:206-216.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Park Y. and E.S. Runkle. 2018. Spectral effects of light-emitting diodes on plant growth, visual color quality, and photosynthetic photon efficacy: White versus blue plus red radiation. PLOS ONE 13(8): e0202386.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. Purple vs. pink vs. white LED fixtures. Greenhouse Product News 28(9):62.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. Using GA to increase plant height. Greenhouse Product News 28(8):42.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. An update on LED lighting efficacy. Greenhouse Product News 28(7):58.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. Horticultural lighting applications. Greenhouse Product News 28(6):58.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. UV radiation and applications in horticulture. Greenhouse Product News 28(5):50.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. Accelerating growth: What works and what does not. Greenhouse Product News 28(4):38.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. Causes of flower bud abortion. Greenhouse Product News 28(3):42.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. Temperature integration. Greenhouse Product News 28(2):38.
  • Type: Other Status: Published Year Published: 2018 Citation: Runkle, E. 2018. Maximizing the benefits of supplemental lighting. Greenhouse Product News 28(1):46.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Does light quantity trump light quality? Greenhouse Product News 27(12):38.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Factors that influence leaf coloration. Greenhouse Product News 27(11):38.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Investment considerations for greenhouse lighting. GPN Vegetable Growers News Sept. 10-13.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Developing new plant lighting standards. Greenhouse Product News 27(10):50.
  • Type: Other Status: Published Year Published: 2017 Citation: Poel, B. and E. Runkle. 2017. Supplemental greenhouse lighting to produce seedlings: LED or HPS? Greenhouse Grower 35(9):59-64.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Sole-source lighting of plants. Greenhouse Product News 27(9):58.


Progress 05/01/17 to 09/30/17

Outputs
Target Audience:• Commercial greenhouse growers, especially those who produce floriculture propagules • Entrepreneurs developing vertical farm businesses to produce high-value specialty crops • Indoor (vertical farm) producers of leafy greens and herbs • Plant lighting professionals, growth chamber manufacturers, and allied companies • Academic and institutional peers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two Ph.D. graduate students are being mentored in this project. In addition, project team members (including graduate students) participated in different regional research meetings (NCERA-101) and scientific converences, including the International Sympsosium on New Technologies for Environment Control, Energy-saving and Crop Production in Greenhouse and Plant Factory, and the American Society for Horticultural Science annual conference. How have the results been disseminated to communities of interest?We have written two articles for grower trade magazines on our initial results, one for Inside Grower and one for GrowerTalks. These were published in their print editions (circulation approx. 18,000) and are also available on their websites and the MSU Floriculture lighting website, http://flor.hrt.msu.edu/lighting. Information was also shared at different grower meetings, including Cultivate'17 in Columbus, OH. What do you plan to do during the next reporting period to accomplish the goals?Research is currently underway to address project objectives, and additional research is being planned for 2018.

Impacts
What was accomplished under these goals? Experiments were performed, or are currently underway, to better understand how the light spectrum can be manipulated to produce crops grown indoors with desired characteristics. Potential advantages of indoor crop production (referred to as vertical farming) include reduced water use, more uniform and consistent crops, greater crop quality, increased yield, better post-harvest performance, reduced use of plant growth retarding chemicals, and reduced use of fertilizers. Our first experiment was designed to quantify how the addition of far-red (FR) radiation influences growth and subsequent flowering of floriculture transplants. We grew seedlings of several common floriculture crops at 20 °C under six sole-source light-emitting diode (LED) treatments with an 18-hour photoperiod. All treatments included 32 µmol m−2 s−1 of blue radiation and the photosynthetic photon flux density (PPFD) was either 96 or 256µmol m−2 s−1. The treatments, identified by the photon flux density (inµmol m−2 s−1) were R64, R64+FR32, R64+FR64, R256, R256+FR128, and R256+FR256. All plants were grown in the same walk-in growth chamber and environmental conditions were monitored daily. Several parameters were measured at the end of the transplant stage, including leaf area, leaf number, stem length, and fresh and dry weight of shoots. In petunia, stem length, individual leaf area, and shoot dry weight linearly decreased as the R:FR increased under both PPFDs. Independent of the R:FR, increasing PPFD decreased stem length and individual leaf area, while increasing shoot dry weight. In addition, inclusion of FR during seedling growth promoted flowering at both PPFDs, but to a greater extent under PPFD 96 than PPFD 288. Data from other species is currently being analyzed and interpreted.

Publications

  • Type: Books Status: Published Year Published: 2017 Citation: Lopez, R. and E.S. Runkle. 2017. Light Management In Controlled Environments. 180 pp. Meister Media Worldwide, Willoughby, OH.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Both, A.J., B. Bugbee, C. Kubota, R.G. Lopez, C. Mitchell, E.S. Runkle, and C. Wallage. 2017. Proposed product label for electric lamps used in the plant sciences. HortTechnology 27:544-549.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Park, Y. and E.S. Runkle. 2017. Far-red radiation promotes growth of seedlings by increasing leaf expansion and whole-plant net assimilation. Environ. Exp. Bot. 136:41-49.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Poel, B. and E.S. Runkle. 2017. Seedling growth is similar under supplemental greenhouse lighting from high-pressure sodium lamps or light-emitting diodes. HortScience 52:388-394.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Meng, Q. and E.S. Runkle. 2017. Moderate-intensity blue radiation can regulate flowering, but not extension growth, of several photoperiodic ornamental crops. Environ. Exp. Bot. 134:12-20.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Lighting tech under the microscope. Greenhouse Grower Technology 2(4):22.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. and B. Bugbee. 2017. Plant light efficiency and efficacy: �mol/J. Greenhouse Product News 27(7):58.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Growing plants with green light. Greenhouse Product News 27(6):58.
  • Type: Other Status: Published Year Published: 2017 Citation: Whitman, C. and E. Runkle. 2017. Asclepias tuberosa, butterfly weed. Greenhouse Product News 27(4):46.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. The importance of light uniformity. Greenhouse Product News 27(3):38.
  • Type: Other Status: Published Year Published: 2017 Citation: Meng, Q. and E. Runkle. 2017. Far red is the new red. Inside Grower Feb.:26-30.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Effects of blue light on plants. Greenhouse Product News 27(2):38.
  • Type: Other Status: Published Year Published: 2017 Citation: Runkle, E. 2017. Vertical farming. Greenhouse Product News 27(1):42.
  • Type: Websites Status: Published Year Published: 2017 Citation: http://flor.hrt.msu.edu/production-info