Effects of ultraviolet-B (UV-B) radiation on two cryptogamic plants pigments growing at high altitude of central Himalayan region, India

Abstract

Chlorofluorocarbons are mainly responsible for the depletion of stratospheric ozone layer which results in  increase of UV-B radiation on earth’s environment and causing adverse effects on flora. In the present  study we have investigated the effect of ultraviolet-B (UV-B) radiation on two cryptogamic plants  (Xanthoria elegans and Bryum argenteum) growing at high altitude of central Himalayan region of India.  These plants were naturally receiving UV-B radiation and were analyzed for photosynthetic pigments, UV-B absorbing compounds and phenolics. In the field experiments, both of these plants contain higher amounts of UV-B absorbing compounds and phenolics and no major changes in total chlorophyll and carotenoid  under UV-B exposed conditions were recorded. B. argenteum contains higher amounts of total chlorophyll, carotenoids, UV-B absorbing compounds and phenolics than the X. elegans at the duration of 120 h. The maximum average UV-B irradiance was 4.38 Minimal Erythemal Dose per hour (MED/ h) at the  experimental site while minimum average UV-B irradiance was 1.72 MED/ h. The UV-B absorbing compounds and phenolics provide protection to these plants against UV-B radiation.

Key words: Total chlorophyll, high altitude, pigments, UV-B absorbing compounds, UV-B radiation.