Author ORCID Identifier
Semester
Spring
Date of Graduation
2024
Document Type
Thesis
Degree Type
MS
College
Davis College of Agriculture, Natural Resources and Design
Department
Division of Plant and Soil Sciences
Committee Chair
Nicole Waterland
Committee Member
Youyoun Moon
Committee Member
Janet Tou
Abstract
Indoor agriculture is a growing industry with many of its benefits being recognized. Light emitting diodes (LEDs) reduce production costs compared to traditional light sources. LEDs emit narrow bandwidths of light that allow growers to easily change the wavelengths plants are being grown under by using different combinations of wavelengths. Manipulating the light that plants are grown under is a method to change their physiology which is the basis of this thesis. The goal of the first two studies was to investigate how different light spectra can be used to enhance the nutrition content, growth, and morphology of kale and tomatoes to improve the quality of food grown under LEDs. Results from these studies showed that generally green and blue LEDs led to more nutrients in kale leaves and tomato fruit while red light lowered the nutritional quality. In kale, antioxidant capacity and phenolic content was highest under blue light while green light produced the highest mineral contents (p < 0.05). Antioxidant capacity of tomato fruit was higher in treatments with blue and green than red while the mineral content of fruit showed the same general pattern (p < 0.05). There were no significant differences in the yield of kale grown to the baby leaf stage or in the total amount of tomato fruit harvested per plant under the different LED wavelengths. However, the height of plants increased under red light which could be negative in a vertical farm setting. Overall, the results show that growers can be more flexible with the wavelengths of light without sacrificing yield in kale and tomatoes, and there may be a benefit to leaving red light out. The third study of this thesis was to understand the gene expression changes that occur under different wavelengths and how they may explain the physiological differences observed in the first study on kale. RNA sequencing was performed on kale grown under pure red, green, or blue LEDs and compared to a control that was grown under all of the LEDs in combination. Green and blue LEDs resulted in more differentially expressed genes (DEGs) while kale grown under red LEDs had an expression profile similar to the control. Kale grown under blue light showed antioxidant enzymes and proteins involved with phenolic biosynthesis were upregulated which potentially explains the physiological differences observed in the prior studies. Under green LEDs kale upregulated many heme binding genes and oxidoreductases, specifically cytochrome P450s. This may explain the significantly higher iron content of kale grown under green light, and supports other literature on green light perception by plants which has remained largely unknown until recently. The transcriptomic data from this study can further the understanding of how plants respond to light, and more mechanisms will be revealed when paired with metabolomic data.
Recommended Citation
Sanders, Tristan D., "LEDs for Controlled Environment Agriculture: Leveraging Light to Optimize Crops" (2024). Graduate Theses, Dissertations, and Problem Reports. 12349.
https://researchrepository.wvu.edu/etd/12349
Embargo Reason
Publication Pending
Included in
Agriculture Commons, Food Science Commons, Genetics and Genomics Commons, Nutrition Commons, Plant Sciences Commons