Abstract:

After tartary buckwheat seeds germinated in darkness for 6 days, their sprouts were cultivated under lightemitting
diode (LED) red light, LED white light, LED blue light, LED UV-B light and fluorescent light, respectively. They
were grown under a 16 h (daytime):8 h (night) photoperiod at 27 ℃ for 3 days. The transcriptional levels of six genes
involved in the flavonoid biosynthesis pathway, FtPAL, Ft4CL, FtCHS, FtFLS, FtF3H, and FtANS, were investigated by
semi-quantitative RT-PCR. The content of total flavonoids was measured by AlCl3 method. The correlation coefficients
between total flavonoids content and the expression levels of flavonoid biosynthesis-related genes in both cotyledons and
hypocotyls were analyzed. Total flavonoids content in tartary buckwheat cotyledons with different light treatments followed
the decreasing order: UV-B > blue > red > white > florescence > dark; as for hypocotyls, the decreasing order was UV-B >
blue > white > red > florescence > dark. Total flavonoids content was significantly correlated with the expression levels
of FtPAL, FtCHS, FtF3H and FtANS in cotyledons (correlation coefficients > 0.75). While FtPAL expression showed the
highest correlation with total flavonoids content in cotyledons with correlation coefficient of 0.921, only Ft4CL expression
level was detected to have a significant correlation with total flavonoids content in hypocotyls with correlation coefficient
of 0.975. In conclusion, flavonoid accumulation during germination of tartary buckwheat could be increased through light
regulation, and UV-B, blue and red light could be mixed for induction of more flavonoids.

Key words: LED light, tartary buckwheat, germination, flavonoids, gene expression