Melatonin triggers salinity tolerance in pansy (Viola tricolor) by regulation of defense system

Salinity poses a significant threat to the floral plants. Melatonin has emerged as a potential phytohormone to cope with the adverse effects of salinity on plants due to its multifaceted roles in regulating abiotic stresses. The current study aimed to investigate the impact of melatonin on pansy by modifications in physiological indices under salinity stress. Pansy plants were subjected to salinity stress (0, 50, and 100 mM NaCl) and melatonin (control, 50, and 100 µM). Salinity-induced oxidative stress was apparent through enhanced generation of toxic substances. However, melatonin supplementation improved chlorophyll 'a', chlorophyll 'b', total chlorophyll, glycine betaine (GB), superoxidase dismutase (SOD), peroxidase (POD), catalases (CAT), and glutathione-reductase (GR), thus promoting improved growth under salinity. The activation of plant defense system and regulation of signaling molecules is indication of lessening of toxic substances within the plant cells. Current findings revealed that supplementation of melatonin enhanced pansy tolerance against salinity stress.