Flavonoids accumulation and UV-B protection in crop plants

Non-photosynthetic pigments such as flavonoids, flavones and anthocyanins present in the epidermal layers are known to act as screens to harmful UV-radiation, thereby protecting internal tissue layers of plants. They accumulate in plant tissues when exposed to UV-B radiation, though the exact mechanism of their action is yet to be defined. A field study, was conducted to determine the effect of enhanced UV-B radiation (9.82 KJ m⁻² UV-B_BE) on accumulation of flavonoids and anthocyanins in the leaves of four crop species viz. wheat, mustard, pea and oat. The level of pigments varied significantly in all four species due to UV-B irradiation as compared to ambient grown plants. Wheat and oat showed accmulation of both pigments, while in case of mustard and pea, there was reduction in the level of these pigments under increased UV-B radiation. The study suggested that monocot plant species are less affected and produce more protective pigments compared to dicot species when exposed to increased UV-B radiation.