FIGURE 3.

Salinity stress induced osmotic stress tolerance mechanism in plants. Salinity leads to build up of Na⁺ and Cl^- in soil, consequently lowering the soil water potential as compared to water potential of plant cells. This leads to reduced water uptake by plants and eventually causes cellular dehydration. Plants, in order to avoid such consequences, accumulate osmolytes, such as proline, trehalose, polyamines, and sucrose in higher concentration. Osmolytes accumulation results in lowering of cellular water potential and thereby maintains a favorable gradient for water uptake from soil to root. Thus, it prevents cellular dehydration and subside osmotic stress caused by salinity. AM symbiosis alleviates osmotic stress by influencing the expression of specific genes (P5CS, pyrroline-5-carboxylate synthase; TPS, trehalose-6-phosphate synthase; SPS, sucrose phosphate synthase; SS, sucrose synthase) involved in the biosynthesis of osmolytes.