Light-emitting diodes (LEDs) of different colors improve plant growth and increase levels of secondary metabolites. This study aimed to determine the effect of red, blue, and red + blue LEDs (1:1) on the secondary metabolites composition in chili, focusing on capsaicinoids, at the top and middle of the plant canopy in ‘Super Hot’ chili. The accumulated yield of the chili fruit was the highest for control, followed by blue, red and red + blue LEDs, with the top canopy giving twice more yield than the middle canopy. UPLC-MS/MS analysis of chili fruit’s methanolic extracts was used to determine capsaicinoids levels. Blue LEDs significantly increased nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin and homodihydrocapsaicin contents by 57 %, 43 %, 56 %, 28 %, and 54 %, respectively, compared to the control. Also, 24 tentatively annotated metabolites, including phenylalanine, cinnamate, and valine, which are involved in the biosynthesis of capsaicinoids, were semi-quantitatively evaluated to determine the impact of LED exposure on the biosynthetic pathway of capsaicinoids. Supplemental blue LED placed at the top and between the canopy may boost the levels of capsaicinoids in chili fruit grown in greenhouses.

不同颜色的发光二极管（LED）可改善植物生长并增加次生代谢产物的水平。这项研究旨在确定红色，蓝色和红色+蓝色LED（1：1）对辣椒中次生代谢产物组成的影响，重点是“超级热”辣椒中植物冠层顶部和中间的辣椒素。对照的辣椒果实的累积产量最高，其次是蓝色，红色和红色+蓝色LED，顶部冠层的产量是中间冠层的两倍。辣椒果实的甲醇提取物的UPLC-MS / MS分析用于测定辣椒素水平。与对照相比，蓝色LED显着增加了去甲氢辣椒素，辣椒素，二氢辣椒素，高辣椒素和高二氢辣椒素的含量，分别为57％，43％，56％，28％和54％。也，半定量评估涉及辣椒素类生物合成的24种带有注释的代谢物，包括苯丙氨酸，肉桂酸酯和缬氨酸，以确定LED暴露对辣椒素生物合成途径的影响。顶部和顶棚之间的补充蓝色LED可能会增加温室中生长的辣椒果实中的辣椒素含量。