Mitigating negative impact of salinity on berseem (Trifolium alexandrinum) by foliar application of salicylic acid

Abstract

Salicylic acid (SA) is a plant growth regulator known to take part in defense responses against different types of stresses, including salt stress. In this study, the role of foliar applied SA in improving the growth of berseem variety ‘Anmol’ under salt stress was examined. Plants were sown in plastic pots in the sand. Plants were treated with different concentrations of salinity (0, 60 mM and 120 mM NaCl) and salicylic acid (0, 100 mg L-1 and 150 mg L-1) was applied as a foliar spray. Salinity stress significantly reduced root and shoot fresh and dry weight, root and shoot length, photosynthetic pigments including Chl. a, b, a/b, total soluble proteins, total amino acids and uptake of K+ and Ca2+ ions in root and shoot tissues. Exogenous application of salicylic acid improved growth traits including shoot length, shoot fresh weight, root length, root fresh and weight, shoot dry weight, pigments contents (Chl. a, a/b and carotenoids). Total soluble protein and amino acid contents, activities of antioxidants peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) were also enhanced by the foliar spray of SA under saline and non-saline conditions. SA played a crucial role in lowering Na+ and Cl− ions content in shoot and root tissues while enhancing the uptake of K+ and Ca2+ ions. The study revealed that 100 mg L-1 SA treatment significantly influenced several plant parameters, including shoot length (8 cm), root length 6.7 cm, chlorophyll (1.2 mg/g FW), total soluble proteins (0.8 mg/g FW) and total amino acids (2.5 mg/g FW), SOD (1.22 U/mg protein), CAT (1.75 U/mg FW), potassium ions (29 mg/g DW), and calcium ions (43 mg/g DW) during salinity stress. Therefore, field use of SA (100 mg L-1) is recommended to enhance the growth of berseem and other fodder crops in saline soils.

Keywords

• antioxidants
• growth regulator
• ionic stress
• SA
• salinity