INDUCTION OF SALT TOLERANCE IN WHEAT (TRITICUM AESTIVUM L.) SEEDLINGS THROUGH EXOGENOUS APPLICATION OF PROLINE

To appraise the potential role of foliar applied proline as an alternative shotgun approach to ameliorate the adverse effect of salinity on wheat, a pot experiment was conducted under controlled environmental conditions, two wheat genotypes; a salt tolerant strain ESW-9525 and a moderately tolerant cultivar kherman were used in this study. Factorial combination of treatments with three replications was arranged under completely randomized design. Seven days old wheat seedlings were exposed to various levels of salinity (0, 60 and 120 Mm NaCl) for one week and applied with foliar proline (0, 50 and 100 mM) one week later. Salinity stress caused a significant reduction in plant growth, leaf photosynthetic pigments, as well as alterations in ionic balance. Foliar applied proline significantly improved root and shoot length, seedling fresh and dry weight, photosynthetic pigments, K+ contents and K+: Na+ ratio. Both genotypes varied considerably in endogenous level of proline (Pro), glycine betaine (GB), total soluble sugars (TSS) and total phenolic contents (TPC) in response to salinity and foliar proline as well. Foliar applied proline 50 mM and 100 mM were found as a stimulus for plant growth triggering the physiological and biochemical attributes, However, 100 mM proline was the most effective to ameliorate the toxic effects of salinity by improving root and shoot length, seedling fresh and dry weight, chlorophyll a, b contents, TSS, Pro, GB, TPC and K+ contents and K/Na ratio in both genotypes. These findings confirmed the ability of foliar applied proline to stimulate the salt tolerance in wheat plants.