Potential of melatonin in enhancing antioxidant defense system and yield of maize (Zea mays L.) hybrids under saline condition

Abstract

Melatonin is a multi-signaling plant hormone that significantly regulate plant growth and development under stress environment. Since a very few crop species have been investigated to disclose the role of exogenously applied melatonin on salt stress, in the current experiment, we investigated the effects of melatonin application by measuring the growth, physio-biochemical and yield attributes of two maize hybrids (2225 and 8711) in saline field (8.9 dS m−1) with two levels of melatonin (0.5 and 1.0 mM). Maize plants from both hybrids grown in saline field show reduced plant growth, fresh and dry biomass, low water contents, grain yield, reduced activities of antioxidant enzymes and poor K+/Na+ ratio due to higher Na+ influx and reduced potassium uptake by plant roots. Our results revealed that foliar application of melatonin at 1.0 mM level on salt stressed maize seedlings alleviated salt induced reduction in plant height, chlorophyll and water contents, reduced the production of proline contents and antioxidant stress indicators (malondialdehyde and hydrogen peroxide contents) and increase cob length along with improved activities of antioxidant enzymes and nutrients concentration in maize grain. Moreover, it was noticed that maize hybrid 2225 show improved growth and eminently responded to melatonin application under all treatments as compared to maize hybrid 8711. The results of the current experiment exhibit the potential of melatonin in mitigate the hazardous effects of salt stress on maize and our findings can provides scientific information for the researchers working on saline agriculture to disclose the potential benefits of melatonin application in achieving sustainable production from salt affected soils.