PROLINE INDUCED CHANGES IN REDOX BALANCE AND PHOTOSYNTHETIC ACTIVITY OF WHEAT (TRITICUM AESTIVUM L.) UNDER SALINE CONDITIONS

Abstract

Salinity is a major environmental constraint that reduces plant development, growth, and yield. To appraise the potential role of foliar-applied proline as an alternative shotgun approach to ameliorate the adverse effects of salinity on wheat, a pot experiment was conducted under controlled environmental conditions using two wheat cultivars (Galaxy-13 salt-sensitive) and (Pasban-90 salt-tolerant). The experiment was laid out in a completely randomized design with the factorial arrangement and four replications. After ten days of germination, the plants were thinned to maintain six plant seedlings in each pot and the germinating seedlings were irrigated weekly with full strength Hoagland’s nutrient solution and salinity stress (NaCl) was applied after three weeks of germination. Foliar spray of proline (100 mM) was applied with the treatment of salinity. Salinity stress caused a significant reduction in morphological attributes like lengths and fresh weights of root and shoot, number of leaves and leaf area as well as yield attributes like spike length, number of spikelets per spike, number of grains per spike, yield per plant and 100 seed weight. Furthermore, chlorophyll fluorescence, chlorophyll contents, quantum yield, and electron transport rate (ETR) were also reduced by salt stress. However, foliar spray of 100 mM proline was the most effective to ameliorate the toxic effects of salinity by improving biomass production, chlorophyll fluorescence, chlorophyll contents, and quantum yield in both the cultivars. The findings confirmed the ability of foliar spray of proline to stimulate salt tolerance in wheat plants.