Salicylic Acid Improves Agro-Morphology, Yield and Ion Accumulation of Two Wheat (Triticum aestivum L.) Genotypes by Ameliorating the Impact of Salt Stress

Abstract

Wheat growth, development and yield are severely affected by a wide range of abiotic stresses, and salt stress is a vital and increasing abiotic stress. Salicylic acid (SA) is a phenolic phytohormone involved in plant physiological processes. Hence, we have conducted an experiment to explore the roles of exogenous SA in mitigating salt stress in two wheat genotypes. There were eight treatments comprising (i) control, (ii) 0.5 mM SA, (iii) 1.0 mM SA, (iv) 1.5 mM SA, (v) salinity (12 dS m−1), (vi) salinity + 0.5 mM SA, (vii) salinity + 1.0 mM SA and (viii) salinity + 1.5 mM SA with two wheat genotypes viz G 200-4 and BARI gom-25. The experiment was laid out in a completely randomized design with five replications. During the vegetative stage, salt stress significantly reduced the relative water content (RWC), photosynthetic rate, stomatal conductance and growth characteristics of both wheat genotypes, while the exogenous application of SA in salt-stressed plants significantly improved the RWC, gas exchange activities and growth performance of both the genotypes. The leaf chlorophyll content was also degraded due to salinity treatment, although it was mitigated by the exogenous application of SA. The imposition of salt significantly reduced the number of days required for maturity, yield-contributing characteristics and the yield of both the wheat genotypes. Salt stress also significantly increased Na+ concentrations and the Na+/K+ ratio, while the K+ concentrations was decreased significantly in both the wheat genotypes. However, the exogenous application of SA in salt-stressed plants significantly reduced the salt stress effects and increased the growth and yield of wheat genotypes by enhancing RWC, gas exchange activities and photosynthetic pigments and maintaining lower Na+ concentrations and a Na+/K+ ratio. Therefore, the findings of this study suggested that the exogenous application of SA improved the salt tolerance of both wheat genotypes.