Physiological and biochemical studies of black gram (Vigna mungo (L.) Hepper) under polyethylene glycol induced drought stress

Black gram (Vigna mungo L. Hepper) is an important nutritious legume plant, the loess plateau with strong drought tolerance and broad adaptability. To understand the adaptation mechanism of black gram under simulated-levels of drought (5, 10 and 20% PEG) stress, and the growth characteristics, physiological parameters including levels of chlorophyll content, reactive oxygen species, and antioxidant enzymes were measured and the changes were compared with control. The result showed the root and shoot length, chlorophyll content, relative water content, stomatal activity, electrolyte leakage, antioxidant, and histochemical activity were carried out for treated and control plants. Experimentally, the drought-induced black gram seedlings of fresh weight, dry weight, and relative water contents found to be decreased with increasing concentrations of PEG. However, the electrolyte leakage and biochemical components (MDA content), antioxidant enzymes (SOD, CAT, POX), isozyme band patterns and histochemical detection of ROS accumulation (H2O2 and O-2(center dot)-) level also enhanced under drought stress. The electrolyte leakage and MDA content were raised at 60% and 20% of severe PEG treatment. ROS accumulation was increased in the PEG treatment when compared to control. Overall, the rapid, accurate, and strong physiological observations from the electrolyte leakage and histochemical detection suggest that modification or enhancement of the biochemical and antioxidant contents would be determine the growth of black gram under PEG induced drought stress.