Effect of supplementary ultraviolet-B radiation on young wheat seedlings

Abstract

Effect of supplementary UV-B radiation (1 mW m(-2)) on photosynthesis, flavonoid content and anatomical changes was studied in young wheat leaves, It was observed that supplementary UV-B radiation did not affect PS II activity, assayed as water to phenylenediamine, However, PS I activity, assayed as reduced dichlorophenol indophenol to methyl viologen, showed an increase, UV-B treatment resulted in qualitative and quantitative changes in UV-B absorb; ing phenolic compounds, Flavonol (Kaempferol) and caumarin showed quantitative increase due to supplementary UV-B exposure to the wheat leaves. Synthesis of cinnamic acid was observed only after 4 days of UV-B treatment, UV-B treatment resulted in significant anatomical changes in the leaves. There was a massive increase in the cutin synthesis, Epidermal cells were. largely destroyed, while hypodermal cells were seen to replace the epidermal cells.