Mechanistic insights of salicylic acid-mediated salt stress tolerance in Zea mays L. seedlings

Abstract

Elevated sodium level (Na+) poses significant threat to crop plant physio-biochemical processes, leading to impaired growth followed by decline in productivity. Addressing this challenge, requires an eco-friendly and cost-effective strategy that enhances plant salt stress tolerance capacity. In this context, the exogenous source of plant growth regulators (PGRs) proved to be an efficient approach. Of various PGRs, salicylic acid (SA) is an emerging signaling molecule that boosts plant stress endurance mechanism. This study investigates SA-mediated salt stress tolerance in maize (Zea mays L.) seedlings, by examining morpho-physiological and biochemical traits. Maize seedlings were subjected to varying levels of salt stress (0, 25, 50, 75, 100, and 150 mM NaCl) for a period of 10-days. The results revealed that, a substantial decline in germination percentage, shoot and root length, plant biomass, vigour index, and various other physiological parameters under salt stress causing concentrations. Conversely, salt stress increased oxidative stress indicators, including hydrogen peroxide (H2O2) and malondialdehyde (MDA), osmolytes and elemental concentrations as well as antioxident enzymes (SOD, CAT, POX, APX, GR, AsA). However, the exogenous supplementation of SA at 0.1 mM significantly restored most morpho-physiological attributes in maize under salt stress conditions. This suggests that SA actively triggers the ascorbate-glutathione (AsA-GSH) pathway and other key enzymes, leading to sodium extrusion and improving antioxidant defense in maize seedlings. This finding provides valuable insights for maize farmers that employing SA could lead to improved maize production in saline soils.