Integrated physiological and molecular approaches to study salt-induced adaptation in halophytes collected from extremely saline lands

Abstract

Diverse halophytes were collected across the extremely salt-affected lands of Haryana to explore their salt potential. Higher levels of Na+ and Cl- were observed in leaves (3.20 and 4.55%) than in stem (0.78 and 1.09%) and root (0.81 and 0.80 %). Interestingly, these plants also accumulated higher concentrations of K+ for their survival. Similarly, Ca2+ accumulation was higher in leaves (1.57%) than in stems (1.15%) and roots (1.18%). The salt tolerance potential of these halophytes was assessed by examining the ratio of accumulation of toxic ions, namely Na/K, Na/Ca, and Na+Cl to K+Ca, resulting in their characterization and ranking from highly salt tolerant to least tolerant. The utilization of this ionic accumulation index has the potential to serve as a criterion for the elimination of surplus toxic ions from soil. The halophytes employed adaptive mechanisms by synthesizing osmolytes, such as proline, soluble sugars, and soluble proteins, in both leaves and roots. The upregulation of genes P5CS and NHX1, responsible for proline synthesis and membrane transportation, further confirmed the halophytes’ ability to tolerate high salinity. The findings of these studies indicated the potential for domesticating salt-tolerant halophytes in salt-affected soils.