Effect of salt stress on growth and physiological parameters of sorghum genotypes at an early growth stage

Physiological regulation affects plant salinity tolerance. The objective of this research was to investigate the effect of salt stress on the physiological regulation in sorghum at early growth stage. Two sorghum genotypes (GT), Bayeqi (salt-tolerant) and PL212 (salt-sensitive), were grown in an artificial climate chamber with a nutrition solution containing 0, 80, 160, and 240 mM NaCl. Results showed that salt-tolerant sorghum had enhanced activities of antioxidant enzymes including catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), and increased stress-related osmolytes including free amino acids, and reducing and soluble sugars. Furthermore, ion regulation plays an important role in the osmotic adjustment. Results also suggest that K/Na+ and Ca-2/N+ ratios are associated with tolerance under salt-stressed environments and higher Na+ and lower K+ and Ca2+ concentrations are deleterious to sorghum growth. As a result, under salt-stressed environments, the salt-tolerant sorghum GT had better growth performance than salt-sensitive sorghum GT, which was evidenced by a greater plant high, leaf area, leaf fresh weight, and root fresh weight. Overall, under salt-stressed environments, the salt-tolerant sorghum GT had better growth performance including yield than salt-sensitive sorghum GT, which was evidenced by a greater plant high, leaf area, leaf fresh weight, and root fresh weight.