Enhanced light intensity increases flavonol and anthocyanin concentrations but reduces flavone levels in the cotyledons of common buckwheat seedlings

Abstract

The effects of two light intensities on the concentration of several flavonoids were investigated in the cotyledons of common buckwheat seedlings. The study was performed on four days old seedlings of cvs. Hruszowska, Panda, Kora and Red Corolla. One group of seedlings was grown under exposure to 180 ± 20 μmol • m -2 • s -1 photosynthetically active radiation, whereas the other group was exposed to 360 ± 20 μmol • m -2 • s -1 . The experiment lasted 5 days. The results revealed that light intensity induces changes in the levels of flavonols and flavones. Increased light intensity contributed to a decrease in the concentrations of all flavone C-glucosides: orientin (luteolin-8-C-glucoside) and iso-orientin (luteolin-6-C-glucoside), and apigenin: vitexin (apigenin-8-C-glucoside) and iso-vitexin (apigenin-6-C-glucoside). Simultaneously, a substantial increase in the content of flavonols, i.e. quercetin O-glycosides, was found. To the best of our knowledge, this is the first evidence to demonstrate the contrary responses of plant flavonols and flavones to light intensity. The content of anthocyanin also increased under exposure to higher light intensity. Our results indicate that quercetin O-glycosides can play a similar role to anthocyanins in the cotyledons of common buckwheat seedlings. Results of correlation analysis indicate that the increase in flavonol and anthocyanin concentrations in response to higher light intensity is maintained through reduced accumulation of flavones and proanthocyanidins.

Changes in the Carbohydrate Profile in Common Buckwheat (Fagopyrum esculentum Moench) Seedlings Induced by Cold Stress and Dehydration

“…The seeds, sprouts and seedlings of both types of buckwheat contain a whole set of phenolic compounds, such as phenolic acids, flavonols, flavones, catechins, and anthocyanins [ 85 , 86 ]. Therefore, buckwheat seedlings are convenient objects for examining the impacts of environmental factors on these compounds [ 87 , 88 , 89 , 90 , 91 ].…”

“…Another study showed that in F. tataricum , low temperature caused significant changes in the expression of histone deacetylases (HDACs) which correlated with flavonoid synthesis pathway genes [ 93 ]. Besides, when F. tataricum was subjected to cold stress, the anthocyanin content in the epidermis and cortex cells of the hypocotyl was twice as high as in the cotyledons increases their resistance to cold [ 91 ]. Moreover, metabolic profiling based on GC-TOF-MS analysis showed that most sugars and their derivatives increase significantly in response to cold [ 94 ].…”

In vitro Production of Plant Nutraceuticals

“…Likewise, light can enhance several metabolites in certain plants as a physical factor [116][117][118] . In this respect, anthocyanins and flavones increased in response to high visible light levels 119 . Similarly, UV-B irradiation stimulates flavonoid synthesis by enhancing the phenylpropanoid pathway in Kalanchoe pinnata 120 .…”

Metabolome and transcriptome profiling unveil the mechanisms of light-induced anthocyanin synthesis in rabbiteye blueberry (vaccinium ashei: Reade)

“…Higher light intensity can increase anthocyanin accumulation in many plants [4,7]. Azuma et al (2012) showed that strong light may significantly induce anthocyanin accumulation in grape peel and simultaneously induce the high abundance expression of DFR, CHS, CHI, F3H, MT, F3'5'H, and GT [8].…”