Drought is one of the major abiotic stresses affecting the agricultural production worldwide. A generally drought tolerant legume, horsegram was chosen to compare and decipher the biochemical mechanisms of drought stress tolerance. For this, 25 day old plants of a drought tolerant (HPK 4) and a sensitive variety (HPKC 2) of horse-gram (Macrotyloma uniflorum L.) were subjected to drought stress (PEG; polyethylene glycol treatment) and control conditions (without PEG) for 48 h. Leaf and root tissues of these horsegram plants were harvested for biochemical and antioxidant enzymatic assays. The Relative Water Content (RWC), proline and phenol content were found to be significantly higher in the tolerant variety under drought stress. While the protein and Malondialdehyde (MDA) content was observed to be significantly higher in the sensitive variety under drought stress. Among the antioxidant enzymes, Peroxidase (POD), Superoxide Dismutase (SOD), Catalase (CAT) and Glutathione-s-transferase (GST) showed significant increase in the tolerant variety than the sensitive one under drought stress. However, Glutathione Reductase (GR) activity was observed to be decreased. The results suggested that higher levels of RWC, phenols and proline accumulation in tolerant variety of horsegram could play an important role in drought stress tolerance. The diverse levels of antioxidant enzymes may be responsible for the differential drought tolerance capacities of the two varieties.
Jyoti Bhardwaj and Sudesh Kumar Yadav, 2012. Comparative Study on Biochemical Parameters and Antioxidant Enzymes in a Drought Tolerant and a Sensitive Variety of Horsegram (Macrotyloma uniflorum) under Drought Stress. American Journal of Plant Physiology, 7: 17-29.