| dc.description.abstract | There are increasing interests to produce culinary herbs and leafy greens in indoor vertical farms (IVFs) due to increasing world population, resource competition, and unusual climate. Light is one of the most important environmental factors, which affects plant photosynthesis, morphology, yield, and secondary metabolism. Advancement of light emitting diodes technology provides researchers the opportunity to optimize lighting conditions in IVFs to improve plant productivity and quality. Therefore, the objective of the present study is to improve plant growth, yield, and nutritional quality in culinary herbs and leafy greens via manipulating the lighting environment in IVFs. Five experiments were conducted in a growth room using green and purple/red basil (Ocimum basilicum) and four Brassica species. Results indicated that higher daily light integrals of 12.9 to 17.8 mol·m^-2 ·d^-1 improved plant photosynthesis, yield, and phytochemical accumulation in green basil plants. In combined red and blue (R&B) light, increases of blue light proportions increased plant photosynthesis, chlorophyll content, and phytochemical concentrations in basil and Brassica species, while plants grown under higher red light proportions had increased stem elongation, leaf expansion, and greater plant yield. Addition of green light to R&B light decreased photosynthesis, chlorophyll content, and yield in all tested plant species. Substituting red or blue light with green light increased plant photosynthesis in the lower leaves in purple basil plants, but showed no effects in green basil plants. Phytonutrients accumulation in green basil plants decreased by substituting blue or R&B light with green light, while decreased in purple basil plants.
by substituting red or R&B light with green light. Substituting photosynthetically active radiation light with far-red light increased plant stem and petiole elongation and shoot FW by 6%-23% in green basil plants, which also resulted in increased phytochemical concentrations and antioxidant capacity. Supplemental ultraviolet-B (UV-B) radiation increased phytochemical concentrations up to 169% in green basil leaves but decreased plant yield, while lower UV-B radiation doses increased antioxidant capacity in Brassica species without yield reduction. In conclusion, this study unveils how plants respond to changes of light intensity, quality, and supplemental UV-B radiation, providing useful information for light source selection in IVFs. | en |
