Effect of continuous light on antioxidant activity, lipid peroxidation, proline and chlorophyll content in Vigna...

Longer photoperiod in form of continuous light (24-h photoperiod without dark interruption) can alter the various physiological and biochemical processes of the plant. This study aimed to evaluate the effects of continuous light on various biochemical parameters associated with the growth and development of Vigna radiata L. (mung bean). The findings showed that leaf size and chlorophyll content of seedlings grown under continuous light were significantly greater than control plants subjected to 12h light/12h dark (12/12h). The activity of antioxidant enzymes superoxide dismutase (SOD, 30.81%), catalase (CAT, 16.86%), guaiacol peroxidase (GPOD, 12.27%), malondialdehyde, (MDA, 39.31) and proline (14.81%) were notably higher in 24/0h light period than 12/12h light period grown seedling at an early stage (on Day 6) while they were constant at the later stage of development. Increased activity of amylase and invertase reveals higher assimilation and consumption of photosynthetic products. This study revealed that plants were stressed at first. However, they gradually became acclimated to continuous light and efficiently used the excess light in carbon assimilation.