EFFECT OF UV-A RADIATION ON PHOTOSYNTHETIC PIGMENTS OF SELECTED CROP PLANTS

ABSTRACT The present work deals with the effect of UV-A radiation and UV-A along with growth regulators on certain pigments in four crop plants, red gram, groundnut, wheat and ragi. Plants were exposed to UV-A radiation for two hours (2 hr) and four hours (4 hr) daily and UV-A irradiated plants were given chemical treatment, AA, IAA and SA at every fortnight starting from seed stage to yield level. At every fortnight the total chlorophyll content, chlorophyll a (chl-a) and chlorophyll b (chl-b) content were estimated. Treatment with UV-A decreased chlorophyll content. Chlorophyll a was more affected than chl-b. Chlorophylls were found to be more sensitive to UV-A radiation in all the four crop plants studied. The harmful effect of UV-A radiation on pigments was found to be less in AA, IAA and SA treated plants. Ragi plants were found to be more sensitive to UV-A radiation and AA being a powerful antioxidant was found to be an effective possible antidote to UV-A radiation followed by SA and IAA. The present work reveals that UV-A has adverse effects on photosynthetic pigments which ultimately lead to the decrease in the productivity and yield of the crop plants like UV-B radiation