Progress 09/01/13 to 08/31/15
Outputs
Target Audience:The target audience reached by our efforts during this reporting period included horticulturists working for commercial, academic and government entities.Test results were published or presented in venues commonly used in the field of horticulture and greenhouse production, including the annual meeting of the American Society for Horticultural Science. Some of the information obtained is also being used by NASA plant scientists in planning vegetable production experiments to be flown on the International Space Station. Changes/Problems:One issue which arose during this study was the backlog of plant tissue analyses. This was expected to be an issue, but was exasperated by analytical equipment failures. The analysis equipment is now operational and tissue samples are being processed. The results of the remaining analyses will be reported in plant science journals. What opportunities for training and professional development has the project provided?Light system development has provided opportunities for technicians to learn new electronic fabrication techniques and to gain experience in working with solid state ligting systems. The plant research component has provided opportunites for undergraduate students to gain training in plant culture, plant lilghting system hardware operation, and chemical analysis techniques. How have the results been disseminated to communities of interest?Thus far through publications in academic journals, invited talks, and presentations at horticultural society meetings. Also through extension outreach with interested growers. We have also disseminated results through our NASA plant payload groups as part of an effort to optimize the nutrition of crop plants grown on orbit for crew consumption. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Work done during this project has demonstrated the impact of blue wavelengths on primary and secondary metabolism in a variety of crops. Results show significant increases in shoot tissue pigments, glucosinolates, and essential mineral elements following exposure to higher percentages of blue wavelengths provided by LED lighting. Short-duration exposure to narrow-band blue (B, 455-470 nm) wavelengths improved the nutritional quality of sprouting broccoli (Brassica oleacea L. var italica) microgreens. Investigating different percentages of blue LED light on the concentrations of nutrition quality parameters of sprouting broccoli microgreens, compared to incandescent/fluorescent light, demonstrated that concentrations of shoot tissue chlorophyll, b-carotene, lutein, total carotenoids, Ca, Mg, P, S, B, Cu, Fe, Mn, Mo, Zn, glucoiberin, glucoraphanin, 4-methoxyglucobrassicin, and neoglucobrassicin were hightest under the 20% B / 80% Red (R, 622-632 nm) light treatment. In general, the fluorescent/incandescent light treatment resulted in significantly lower concentrations of most metabolites measured in the sprouting broccoli tissue. Another test measured the impact of fluorescent/incandescent light and different percentages of blue/red LED light; and different levels of nutrient fertility on the concentrations of nutritionally important pigments in Chinese kale (Brassica oleracea var. alboglabra) grown to the 30-d baby greens stage. Shoot tissue violaxanthin, neoxanthin, antheraxanthin, lutein, beta-carotene, chlorophyll a, and chlorophyll b concentrations were significantly higher under the LED light treatments. The pool of xanthophyll cycle pigments (zeaxanthin + antheraxanthin + violaxanthin) and the percentage of de-epoxidized xanthophylls (zeaxanthin + antheraxathan) were also significantly higher under all LED treatments when compared to the fluorescent/incandescent light treatment. Higher fertility levels resulted in higher shoot tissue concentrations for most of these same pigments. Results from the current study support previous data showing stimulation of nutritionally important shoot tissue pigment concentrations following exposure to higher percentages of blue light wavelengths from LEDs. A large Basil experiment looking at the use of supplemental lighting using various blue/red LED lighting ratios vs. HPS supplemental lighting. This experiment was replicated for fall, winter, spring and summer greenhouse conditions and was just completed. Early results look like that even in the high light conditions of summer the supplemental blue/red LED lighting increased secondary metabolites and carotenoids. Analytical work on harvested plant tissue is underway and the results of this testing will be published when the analyses are complete. Tests were also done to evaluate the effects of light quality on shoot growth, flower development, mineral uptake and pigment content of marigold (Tagetes patula "Safari Orange"). The data indicates that even in the presence of relatively high DLI from natural sunlight, supplementation with relatively low photon flux densities of blue light from LEDs may be useful in increasing the phytonutrient content of marigold flowers. Most pigments were higher in the high blue LED treatment than in the HPS treatment as well. Thus, LED lighting may have an advantage over HPS lighting (which is currently the most used system in commercial greenhouses) in improving flower color. Further research is warranted to determine if LED treatments can be optimized for greenhouse production to improve both esthetics (color) and phytonutrient content of marigold flowers Work to determine the amount of supplemental LED light required for optimizing the production of important nutritional metabolites appears to indicate that in general, between 20 and 30% (20-30 µmol m-2 s-1) blue supplementation seems to be having the greatest impact on secondary metabolites without causing severe growth reduction, even in summer under relatively high ambient light. The perception of energy-rich blue light by specialized plant photoreceptors appears to trigger a cascade of metabolic responses, which is supported by current research showing stimulation of primary and secondary metabolite biosynthesis following exposure to blue wavelengths. Management of the light environment may be a viable means to improve concentrations of nutritionally important primary and secondary metabolites in specialty vegetable crops. Part of this effort included evaluation of LED lighting configurations from both practical engineering and economical considerations that would be effective in supplemental lighting applications under commercial protected culture conditions in the presence of available natural sunlight. After considering multiple configurations for providing supplemental LED lighting in a greenhouse setting, we identified two configurations that worked well, a horizontal LED bar system and a vertical tower lighting system. The horizontal bar system is placed in close vicinity to the plant canopy and provides desired light quality and levels while allowing natural light to reach the canopy through the spaced light bars. This configuration is energy efficient as little light is lost to scattering and it is effective for standard sized crops grown on greenhouse benches. The vertical tower system is an in-canopy system that works well for large cropping systems such as high wire tomato culture. For the purposes of this project most of the lighting systems produced were of the horizontal bar type since plant tests were being conducted with herbs, small flowering plants, and salad type crops. For sole source lighting, multispectral panels were developed that could be operated in a controlled environment chamber. The panels provide significant flexibility in control of light quality and quantity, and generated uniform lighting over the plant canopy. These lights produce little radiant heat so they have minimal thermal impact on the plants in a closed system.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Kopsell, D.A., C.E. Sams, and R.C. Morrow. 2015. Blue wavelengths from LED lighting increase nutritionally important metabolites in specialty crops. HortScience 50(9):1285-1288. Published as part of the colloquium "The Importance of Light Quality for High Value Plant Products", during the 2014 ASHS Annual Conference.
- Type:
Journal Articles
Status:
Submitted
Year Published:
2015
Citation:
Kopsell, D.A., C.E. Sams, and R.C. Morrow. Sole Source LED Lighting and Fertility Impact Biomass, Shoot Tissue Pigments and Xanthophyll Cycle Flux in 30-day-old Chinese Kale. Submitted to Journal of the American Society for Horticultural Science.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
2015 112th Annual International Conference of the American Society for Horticultural Science. New Orleans, LA, August 4-7. Poster presentation: Sole-source LED lighting impacts mineral nutrient density of Chinese kale.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
2014 111th Annual International Conference of the American Society for Horticultural Science. Orlando, FL, July 28-31. Invited Oral Colloquia Presentation: LEDs create a less stressful light environment and increases in higher-energy blue wavelengths will increase production of nutritionally important metabolites in specialty vegetable crops.
- Type:
Conference Papers and Presentations
Status:
Submitted
Year Published:
2016
Citation:
Sams, C.E., D.Kopsell, and R.C. Morrow. Light quality impacts on growth, flowering, mineral uptake and petal pigmentation of marigold. Submitted to ISHS Lighting Conference.
|
Progress 09/01/13 to 08/31/14
Outputs
Target Audience: The target audience reached by our efforts during this reporting period was horticulturists working for commerical, academic and government entities. Preliminary results were published or presented in venues commonly used in the field of horticulture and greenhouse production, including at the annual meeting of the American Society for Horticultural Science. Changes/Problems: There were no major changes in our approach made during the first year. The following minor problems were observed: After long duration operation in a greenhouse environment, we identified some issues with the earlier LED bar design. Improvements to the design of the bars used in the new system included: Addition of screens to cooling fans to prevent the ingestion of insects Better sealing of the cover to prevent condensation from forming inside the bar Modified the LED strip design to use “snap-together” connectors for easier assembly, which also fixed a problem with thermal expansion causing failure of the old board-to-board jumper system. Changed bar stock color to silver to minimize thermal expansion during the summer. Long lead times to obtain some LED wavebands, and variability in LED lots requiring subselection of parts, has increased the time needed to fabricate the LED arrays. What opportunities for training and professional development has the project provided? Light system development has provided opportunities for technicians to learn new electronic fabrication techniques and to gain experience in working with solid state lighting systems. The plant research work has provided opportunities for undergraduate and graduate students to gain training in plant culture, plant lightiing system hardware operation, and chemical analysis techniques. How have the results been disseminated to communities of interest? Thus far through publications in academic journals, invited talks, and presentations at horticultural society meetings. Also through extension outreach with interested growers. What do you plan to do during the next reporting period to accomplish the goals? Both large LED arrays will be operational at the start of the next project period so that larger scale plant testing can begin during the fall growing season. These tests will include more evaluation off plant nutrition and secondary metabolic product production under different lighting protocols in an actual greenhouse setting. We will also set up and test a segment of a variable lighitng microgreens production system.
Impacts
What was accomplished under these goals?
During the first year of this project large LED array development was undertaken (two 80 square ft systems), growth chamber light quality tests were continued from Phase I, greenhouse supplemental lighting tests started, and the commercialization strategy report was completed. The progress toward the original work plan is summarized by task below. Task 1. Measuring impacts of LED wavebands and light intensities on specialty crop quality factors In the first year of the SBIR Phase 2 project we conducted four (4) experiments in the growth chamber environment to measure the impacts of narrow-band wavelengths of light from LEDs. Some of the results of these on-going tasks were published in one refereed journal article (Kopsell et al., 2014). We also delivered one (1) oral invited colloquia presentation and two (2) poster presentations (Lowery et al., 2014 and Kopsell et al., 2014) at the 2014 American Society for Horticultural Science (ASHS) annual meeting (July 28-31 in Orlando, FL) related to these tests. Task 2. Impacts of supplemental LEDs in greenhouse setting on specialty crop quality factors For these projects LED light was provided at 100 µmol m-2 s-1of light from the LED source in addition to the natural sunlight. In some of the projects (as indicated) the same amount of light supplementation was also provided from HID lighting for comparison to the LED sources. Study 1 Objective: Determine the impact of supplemental blue or red and blue LED light on growth and phytonutrient content of kale grown to the baby stage. Results: Fresh and dry weight of kale was highest in the red and blue LED treatment and reduced by about 20% in the blue-only LED treatment. LED treatments resulted in over 400 percent more fresh and dry mass than the ambient light treatments. Glucosinolates and mineral uptake were both higher (10 to 20 %) in the LED exposed plants compared to the plants grown in ambient light. Study 2 Objective: Determine the impact of supplemental LED (50% red, 50% blue) or (75% red, 25% blue) and HID light on the growth, mineral uptake, and flavor compounds of basil. Results: Fresh and dry weights of basil grown with supplemental 75% red and 25% blue LED light were higher than that of basil grown with 50% red and 50% blue LED light. The fresh and dry weight of plants grown with supplemental HID light were similar to those grown with 50% red and 50% blue LEDs. All of the supplemental light treatments resulted in higher fresh and dry weights than the ambient light treatments (>100% higher). The mineral nutrient uptake was also greater in the LED light treatments. We are currently evaluating the flavor compounds from these treatments. Plants grown with the LED supplement treatments appeared to have a greater aroma than those grown with the ambient light treatments or the HID treatments. Study 3 Objective: Determine the impact of supplemental LED (50% red, 50% blue) or (75% red, 25% blue) and HID light on the growth, mineral uptake and carotenoid content of marigolds. Results: Fresh and dry weights of marigolds grown with supplemental 75% red and 25% blue LED light or 50% red and 50% blue LED light were higher than that of marigolds grown with supplemental HID light. All of the supplemental light treatments resulted in higher fresh and dry weights than the ambient light treatments (>100% higher). The mineral nutrient uptake was also greater in the LED light treatments. We are currently evaluating the carotenoids from these treatments. Plants grown with the LED supplement treatments appeared to have a greater aroma and be darker green than those grown with the ambient light treatments or the HID treatments. Study 4 Objective: Determine the impact of supplemental LED (50% red,50% blue) or (75% red, 25% blue) and HID light on the growth, mineral uptake and carotenoid content of zinnias. Results: Fresh and dry weights of zinnias grown with supplemental 75% red and 25% blue LED light or 50% red and 50% blue LED light were slightly lower than that of zinnias grown with supplemental HID light. All of the supplemental light treatments resulted in higher fresh and dry weights than the ambient light treatments (>20% higher). The mineral nutrient uptake was also greater in the LED light treatments. We are currently evaluating the carotenoids from these treatments. All of the 4 studies above establish that providing supplemental LED light will increase the growth and nutrient content of plants grown under ambient greenhouse light conditions. We are still currently evaluating the large amount of data from these experiments on glucosinolates, carotenoids, minerals, and aroma compounds. From the data so far it also appears that 25% supplemental blue light from LEDs resulted in greater increases in growth than the 50% LED light supplement. Further experiments will refine how much blue and red light (and potentially other wavelengths) supplementation is needed to optimize growth. Study 5 Objective: This test was a trial run in the greenhouse facility at a commercial grower facility near the University of Tennessee-Knoxville. We established a 100% blue and a 75% red and 25% blue LED supplemental light treatment in the greenhouse of one of our commercial greenhouse cooperators in January of 2014. The grower compared the growth of several herbs under these treatments with plants growing in ambient greenhouse light. We collected samples from these plants to analyze for mineral content and flavor compounds. The grower reported that the flavor and aroma of these plants was better than that of the plants in ambient light conditions. The grower also reported >200% increased in growth of tarragon with the supplemental LED light. The grower is eager to establish a larger replicated trial for several herbs in the greenhouse this winter. Grower reported results are below: Plants under red and blue grow light look a little stronger and taller than under blue light. Plants growing naturally in greenhouses, look much weaker / smaller than plants grown under both types of grow lights. Production rates are three times slower than in plants grown under grow lights. Chives growing in the hydroponic channels next to grow lights demonstrate two times faster production rates, looks healthier, and early blooming. Task 3. Micro/petite green production test system The objective of this task is to set up a system for producing phytochemically and nutritionally enhanced microgreens. Microgreen production is a good system to transition to commercial production due to the rapid crop cycle and small plant size. This task will be undertaken during the second year of the project using LED system designs developed during the first year of the project. A phased lighting system will be used to provide variable light quality at different stages of plant development. Currently we are working to select hardware components to build a segment of this production system. LED lighting bar fabrication During Phase 1, the configuration of the lighting used for the sole source lighting tests included multicolor square panels, and initial greenhouse testing was done using small arrays of linear lighting bars. For Phase 2, a large LED bar configuration was developed. This configuration consisted of a 20-foot array composed of four modules. Each module can accommodate up to 12 LED bars. To provide the maximum flexibility for research, each module provides independent control of up to three different LED colors. Different bar colors can be inserted in any combination as desired. Each of the four modules operates independently, thus the system has independent control of up to 12 different wavebands. The LED bars for each module do not need to be congruous in the array and can be positioned anywhere along the 20ft length that is desirable to meet experiment objectives. Wavebands that are currently available for these lighting systems include: 400nm, 450nm, 540nm, 617nm, 630nm, and 735nm.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Kopsell, D.A., C. E. Sams, T. C. Barickman and R.C. Morrow. 2014. Sprouting Broccoli Accumulate Higher Concentrations of Nutritionally Important Metabolites under Narrow-band Light-emitting Diode Lighting. J. AMER. SOC. HORT. SCI. 139(4):469477.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Lowery, H.D., D. A. Kopsell and C. E. Sams. 2014. Nutritional quality parameters in kale cultivars are higher under narrow-band LED light than under fluorescent/incandescent light. Poster presentation at the 2014 American Society for Horticultural Science (ASHS) annual meeting, July 28-31 in Orlando, FL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Kopsell, D.A, C. E. Sams, and R.C. Morrow. 2014. Nutritionally important pigments in baby Chinese kale are higher under narrow band LED light than under fluorescent/incandescent lighting in controlled environments. Poster presentation at the 2014 American Society for Horticultural Science (ASHS) annual meeting, July 28-31 in Orlando, FL.
|