Exogenous Melatonin Protects Lime Plants from Drought Stress-Induced Damage by Maintaining Cell Membrane Structure, Detoxifying ROS and Regulating Antioxidant Systems

Lime is an important commercial product in tropical and subtropical regions, where drought stress becoming one of the most severe environmental challenges agricultural sector. Melatonin antioxidant molecule that helps plants regulate their development respond to a variety stresses. In this research, effects exogenous melatonin treatments were evaluated at different concentrations (0, 50, 100, 150 ?M) on biochemical aspects gene expression two species lime (“Mexican lime” “Persian lime”) under normal (100% field capacity (FC)) conditions (75% 40% FC). The experiments factorial based completely randomized design (CRD) with four replicates. Drought caused electrolyte leakage (EL) as well accumulations hydrogen peroxide (H2O2) malondialdehyde (MDA), indicating occurrence damage cellular membranes. contrast, pretreatment various reduced levels EL, H2O2 MDA while mitigating negative species. application (100-?M) significantly increased level proline content activity enzymes compared control plants. According real-time PCR analysis, treatment enhanced genes involved ROS scavenging, biosynthesis, cell redox regulation both species, respective controls. these findings, able detoxify systems, thereby protecting from stress-induced damages.