Development of a Variable-Spectra LED Array for Optimized Plant Development

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Hawley, David

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University of Guelph


Plant development can be dramatically influenced by the quality of light present in its environment. Conventional plant lighting systems do not allow for fine control of light quality, which may not be optimal for all species. To address this problem, a novel lighting system was developed using narrow-bandwidth, multi-coloured LEDs. This system was used to test the effects of different light qualities on germination rate, photosynthesis during vegetative growth, and the photosynthetically adaptive nature of several species. It was found that far red light and blue light can significantly inhibit germination in some species. Red and deep red light was generally most effective at driving photosynthesis during vegetative growth. Plants were shown to have an impaired photosynthetic capacity when abruptly switched to a new light quality. Optimizing germination and photosynthesis are the first steps in designing optimal light “recipes” for plant production.



LED, plant, royal blue, blue, cyan, green, amber, red, deep red, far red, photosynthesis, carbon fixation, PAR, tomato, lettuce, pepper, germination, photoblastic, adaptation, light quality