Salinity stress is a worldwide problem, constraining global crop production seriously. Recent global climate change has made this situation more serious. Exogenous application of potential protectants such as salicylic acid (SA) and thiourea (TU) can be an important approach to alleviate the adverse effects of salinity stress on plants. Therefore, a hydroponic experiment was therefore conducted to investigate the ameliorating effect of SA and TU on salt stress in a wheat genotype BARI Gom-30 considering the growth traits, photosynthetic parameters and antioxidant enzyme activities. The experiment was laid out by following complete randomized design (CRD) with three replications and five treatments viz., control, salt, salt+SA, salt+TU, and salt+SA+TU. Salinity stress caused significant reductions of different growth traits such as plant height, shoot and root length, shoot and root fresh weight, shoot and root dry weight in wheat genotype. The leaf water status, different photosynthetic parameters and intracellular proline contents were severely shortened in the leaves of salt stressed plants. However, exogenous application of SA or TU on salt stressed wheat plants showed a significant increase in growth traits by up regulating the levels of chlorophyll content, photosynthetic pigments and proline contents in compared to salt treated plant alone. The higher Na+/K+ was noted in the leaves of stressed seedlings and therefore, the wheat plants suffered more oxidative damage due to the higher production of H2O2 and MDA under salinity stress. Besides, the activities of antioxidant enzymes namely CAT, POD and APX were slightly enhanced due to the imposition of salt on wheat seedlings compared to control treated plants. On the contrast, SA or TU mediated ameliorating effect of salt stress caused the lower Na+/K+ was considerably reduced as well as the production of H2O2 and MDA were significantly lowered in BARI Gom-30 might be due to the higher increment of CAT, POD and APX enzyme activities in the stressed wheat genotypes supplanted with SA or TU which reflecting the positive role of SA or TU against salt-induced oxidative stress in BARI Gom-30. The the individual foliar application of SA and TU was found to be more effective in improving salt stress tolerance in BARI Gom-30, however, the combined application of SA and TU was not found as so effective to mitigate salt induced toxic effect in wheat plants.
Key words: Wheat, salinity, hydroponic experiment, proline contents, antioxidant enzymes
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