Seasonal variation on the UV-B enhanced solar radiation induced changes in Cyamopsis tetragonoloba L.

摘要

Cluster bean (Cyamopsis tetragonoloba L) plants grown under ultraviolet-B (UV-B, 280-320 nm) enhanced solar radiation during the summer and monsoon seasons showed large variation in their growth characteristics. Both the growth and fresh weight had decreased under UV-B enhanced solar radiation. The total chlorophyll content had decreased in plants grown under UV-B enhanced radiation, whereas the carotenoid and flavonoid levels had increased to various extents. The rate of photosynthetic O₂ evolution mediated by the photosystem 2 (PS2) was reduced in both seasons in plants grown under UV-B enhanced radiation. The fruit yield in monsoon plants was lesser than that in summer plants and UV-B radiation had further reduced this level. Overall growth and fruit yield response of cluster bean plants in the monsoon season was lesser as compared to the summer plants and such reduction is attributed to the prevalence of low ambient and high level of solar UV-B radiation.