EVALUATING CHANGES IN WHEAT GENOTYPES CAUSED BY HYDROGEN PEROXIDE DURING SEED TREATMENT AND THEIR INVOLVEMENT IN SALT TOLERANCE
Keywords:membrane stability index, reactive oxygen species, salinity, wheat
Two wheat genotypes (Khirman and Inqalab) were used to evaluate the physiological and biochemical changes caused by presoaking of seeds with different levels of hydrogen peroxide (0, 20, 40, 60, 80 and 100 µM) against two salinity levels (0 and 100 mM NaCl). The data were recorded on membrane stability index, relative leaf water content, stomatal conductance, photosystem II efficiency and antioxidant assay. The results showed that the membrane stability index was significantly influenced by genotypes and salinity, while it was non-significantly influenced by H2O2 seed soaking concentrations. The relative water content was not affected by treatment, hence no significant effects of treatment or salinity were observed. The H2O2 seed treatment seems to protect the salt sensitive genotype Inqalab against yield reductions caused by salinity. The most important observations were protective effects of H2O2 treatment on salinity stress for stomatal conductivity. Salinity tends to decrease conductivity, while H2O2 treatment increased it. Salinity did not significantly affect Fv/Fm, but there was a significant effect of H2O2. The H2O2 treatment might strongly enhanced photosynthesis via its beneficial effect on Fv/Fm. The H2O2 signals the establishment of antioxidant activity in seeds, which persisted in the seedlings to balance the ion-induced oxidative damage. The data on antioxidant assay showed that treatment tends to reduce plant H2O2 levels, which was a significant effect. However, the data did not show any clear evidence that salt stress had caused increased levels of H2O2. On the whole, beneficial effect of H2O2 was observed on both wheat genotypes.