Salicylic acid and silicon cross talk influence physiological and biochemical attributes of sorghum under salinity stress

Salinity stress is a major abiotic constraint limiting crop productivity worldwide. Sorghum bicolor is an important cereal crop cultivated in semiarid regions and exhibits moderate tolerance to salinity stress. Therefore, the present study evaluated the effects of foliar application of salicylic acid (SA) and silicon (Si) on the physiological, biochemical, and yield attributes of sorghum under saline conditions. Greenhouse pot experiments were conducted during Kharif 2020 and 2021 at CCS Haryana Agricultural University using sorghum cultivar HJ 513. The experiment was conducted in a factorial completely randomized design with three replications under three salinity levels (0, 7.5, and 10.0 dS m⁻¹ NaCl). Salicylic acid (0, 1.0, 1.5, and 2.0 mM) and silicon (0.5, 1.0, and 1.5 mM) treatments were applied separately as foliar sprays at the flowering stage, and pooled data from two years were statistically analyzed. Salinity stress significantly reduced plant height, leaf area, biomass accumulation, relative water content (RWC), chlorophyll content, SPAD value, and seed yield compared with the control treatment (untreated), while malondialdehyde (MDA) content and electrolyte leakage increased under saline conditions. Foliar application of SA (1.5 mM) and Si (1.5 mM) significantly improved RWC, chlorophyll content, SPAD value, and yield traits while reducing MDA accumulation and electrolyte leakage under salt stress conditions. Significant positive correlations were observed among physiological, biochemical, and yield parameters. The results indicate that exogenous application of SA and Si alleviated salinity-induced damage and improved stress tolerance in sorghum under greenhouse conditions. Therefore, SA and Si may serve as promising management strategies for improving sorghum performance under saline environments. Further studies under field conditions and at the molecular level are needed to validate the long-term effectiveness of SA and Si application for improving salinity tolerance in sorghum.