Zhawar, Vikramjit KaurTanotra, Suchita2017-12-032017-12-032017http://krishikosh.egranth.ac.in/handle/1/5810036772Hydrogen peroxide (H2O2) and nitric oxide (NO) signallings were studied under ABA and under water deficit stress using H2O2/NO producers and scavengers in shoots and roots of two wheat cultivars contrasting in drought tolerance. PBW 644 (drought tolerant cultivar) showed higher activities of antioxidant enzymes (catalase, glutathione reductase, superoxide dismutase monodehydroascorbate reductase) and invertases (cell wall bound and soluble), higher levels of ascorbate, ascorbate to dehydroascorbate ratio, proline, sucrose under control, ABA supply and water deficit conditions as compared to PBW 343 (drought susceptible cultivar). Under these conditions, H2O2/NO-signalling were found to upregulate these parameters in both cultivars but regulations were higher in PBW 644. H2O2 and NO-signallings did not differ from each other rather appear to produce almost similar regulations under these conditions. PBW 644 also showed improved root growth (primary root, lateral root and number of axile roots) under water deficit stress, this was related to the presence of endogenous ROS-signalling, however this feature was not shown by PBW 343.ennullThesis