Abstract: In this study, the morphology, total phenols and total flavonoids contents of buckwheat sprouts from seven tartary buckwheat cultivars and three common buckwheat cultivars were evaluated. As a result, the tartary buckwheat cultivar ‘Mongolia 2’ and the common buckwheat cultivar ‘Xinong 9976’ were selected as the most suitable for the production of buckwheat sprouts. The selected cultivars were germinated under different conditions of light-emitting diode (LED) illumination. The contents of total phenols and flavonoids in buckwheat sprouts were determined and the expression levels of the genes encoding phenylalanine synthase (PAL), flavonol synthase (FLS), chalcone synthase (CHS) and chalcone isomerase (CHI) were analyzed. Furthermore, the underlying mechanism was elucidated. It turned out that white light was identified as the optimal LED illumination for ‘Mongolia 2’, increasing the contents of orientin and isoorientin by 63% and 69% after 6-days’ of germination, respectively, and increasing total flavonoid content by 40%–53% on days 2 to 6. However, the optimal LED illumination for ‘Xinong 9976’ was red light, increasing the contents of rutin and total flavonoids by 70% and up to 111% after 6-days’ germination and on days 2 to 6, respectively. Red light was the optimal LED illumination treatment for improving the content of total phenols in buckwheat sprouts from both cultivars (by up to 83% on days 2 to 6 for ‘Xinong 9976’). Moreover, the expression levels of PAL, FLS, CHS, and CHI were significantly up-regulated in buckwheat sprouts after LED illumination treatment.

Key words: buckwheat varieties; buckwheat sprouts; flavonoids; light; gene expression