The compensatory effect of glutathione on alleviating salinity–induced modulations in growth and biochemical traits in maize irrigated with diluted seawater

Abstract

Salinity stress has recently received much attention as an object worthy of research and interest. It is a great challenge for the future global agricultural production that aspires to a large-scale conversion of raw seawater to irrigation use. Our study aims to investigate the antioxidant and free radical scavenging effect of glutathione (GSH) that would enhance maize tolerance to the destructive effect of salinity. A greenhouse trail was conducted in this context during the summer season of 2015 using two salinity (Mediterranean seawater: 3000 and 6000 ppm) and GSH (100 and 200 pm) levels. Tap water was used as a control. Individually, saline water acted in a distinctly different manner than GSH. Irrigation with diluted seawater caused morphological alterations consistent with chemical imbalance. The weight, stem diameter and longitudinal growth of maize were substantially reduced, while enzymatic and non-enzymatic antioxidant components were positively enhanced. Amino acid composition was significantly higher only among plants received low salt concentration (3000 ppm). Glutathione application alone had a strong impact in promoting maize growth. However, lower response was noted at the level of antioxidant-related substances and amino acids content in comparison with salinity treatments. In stressed plants, glutathione mitigated the detrimental effects imposed by salinity, both at the morphological and biochemical levels. Concurrently, the alleviative effect increased as GSH concentration increased. In view of the results obtained irrigation maize with diluted seawater is possible, yet the cumulative adverse effects of salt on land safety should be considered. Our results suggest that using GSH enhances maize tolerance to salinity, and promotes plant recovery from the stress.