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

Ali Doğru

doi:10.14720/aas.2021.117.1.1964

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.

Highlights

Salt stress is one of the most prominent agricultural problems for plant productivity in the arid and semiarid soils in the world
Root growth was adversely affected by salinity in ‘P3167’ and ‘32K61’ (p < 0.05) while it was not changed by salt stress in Bora (P > 0.05) (Fig. 1a)
Shoot growth declined by 27 % in ‘P3167’, 12 % in ‘32K61’, and 22 % in ‘Bora’, and all these changes were significantly different from respective controls (p < 0.05) (Fig. 1b)

Summary

Introduction

Salt stress is one of the most prominent agricultural problems for plant productivity in the arid and semiarid soils in the world. In plants under optimal growth conditions, the balance between reactive oxygen species (ROS) formation and detoxification is tightly controlled by the antioxidant system (Hameed et al, 2011). Salt stress may cause the accelerated production of reactive oxygen species (ROS) and oxidative stress in the plant cells as a result of higher leakage of electrons toward O2 during photosynthetic and respiratory electron transport reactions (Asada, 2006). Higher plants have developed several adaptive mechanisms to cope with oxidative stress under saline conditions such as the increased synthesis of osmoprotectants. Among phenolic compounds anthocyanins have been well known to accumulate under salt stress and play an important role in scavenging ROS in plant tissues as well (Petridis et al, 2012; Chunthaburee et al, 2016)

Methods

Results

Conclusion