PJB-2018-363
ATTENUATING THE ADVERSE EFFECTS OF SALINITY STRESS BY EXOGENOUS APPLICATION OF MELATONIN IN WHEAT (TRITICUM AESTIVUM L.) GENOTYPES
SARA ZAFAR
Abstract
Melatonin (N-acetyl-5-methoxytryptamine) has emerged as a new growth regulator in plants due to its positive role in alleviation of abiotic stresses. The regulation effect of melatonin in mediation of salinity stress on antioxidative activities, growth and yield of wheat plants was investigated using genotypes Sarsabz and S-24, grown under 10 dSm-1 NaCl salinity stress. Different concentrations of melatonin (50, 100, 300 and 500 µM) were applied foliarly after 30 days of sowing (DAS). Results revealed that melatonin under salinity stress significantly improved the growth and yield of both wheat genotypes as compared to non-treated ones. The yield was enhanced to 5 and 11% by 50 µM melatonin in both wheat cultivars respectively, which increased further 44 and 48% at 500 µM melatonin level in Sarsabz and S-24 respectively, as compared to salinity alone treatment. Furthermore, foliar spray of melatonin was effective in improving the activities of catalase, peroxidase and superoxide dismutase under stress conditions in wheat genotypes. The application of 500 μM melatonin was more effective in reducing the oxidative damage under salinity stress in terms of activities of antioxidant enzymes with an alternate decrease in malondialdehyde content. The increased activities of antioxidant enzymes are positively related with an enhanced biomass production and yield showing the ameliorative effect of melatonin under salt stress condition by up regulating the antioxidative defense mechanism. Results suggested that the foliar application of melatonin can be a useful strategy for enhancing salinity tolerance for yield of wheat plants.
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