Effects of salt stress on physiological and biochemical responses of three maize genotypes at the early seedling stage

Abstract

Salt stress is one of the major global problems for crop productivity in the arid and semi-arid regions of the world. In this study, variations in some physiological parameters, water relations, and antioxidant systems under salinity (300 mM NaCl) among three maize (Zea mays L.) genotypes (‘P3167’, ‘32K61’, and ‘Bora’) were investigated. Our result indicated that shoot growth is more sensitive to salinity as compared to root growth. Salt stress led to physiological drought in all maize genotypes as indicated by the significant decrease in relative water content and increase in water deficit index. Salt stress increased SOD activity in all genotypes showing an efficient formation and detoxification of superoxide radical. The constant level of oxidative markers (MDA and H2O2) and the increased level of the reduced ascorbate and phenolic may indicate that non-enzymatic antioxidants are responsible for the elimination of oxidative stress. Changes in ascorbate peroxidase and glutathione reductase activities under salinity demonstrated a functional failure in the ascorbate-glutathione cycle, especially in ‘P3167’ and ‘32K61’. Based on the presented results we may conclude that the genotype ‘Bora’ is tolerant to salinity while ‘P3167’ and ‘32K61’ are sensitive.

Keywords

• antioxidant system
• oxidative stress
• phenolics
• salinity
• soluble sugars