Physiology of Salt Stress in Plants

The unique ability of halophytes to accumulate salt ions in the root and shoot vacuole with very low leakage provides them the unique ability to extract salts from the soil. It thus may act in the desalinization of degraded land. Some halophytes such as S. brachiata (40% of dry weight) and Atriplex sp. (39% of the dry weight) serve as the salt accumulator (Barrett‐Lennard 2002) and therefore can be extensively used for the phytoremediation. Panta et al. (2014) have provided a table of the halophytes from the previously published report, which describes different species from the genus Suaeda, Atriplex, Tectocornia, Sesuvium, Anthrocnemum, Excoecarcia, Ipomoea, Batis, and Salicornia , which were used in past or have a high potential in coming future for the desalinization and removal of the heavy metals from the degraded soil.

Salt stress affects plants’ survival and productivity. Research on understanding the mechanism of salinity stress gave us significant insight into the plants’ response to salt stress and how halophytes respond differently than the glycophytes. However, the complete mechanistic understanding of the salt tolerance mechanism in the halophytes at the developmental and intracellular molecular levels is lacking. To meet the food, feed, fiber, and fuel demand of the growing human population and improve the abiotic stress resilience of the crop, there are two ways to pursue in parallel; one, adopting the halophyte for food, forage, and fuel generation by growing them in the salt‐affected land, and, second, understanding the salt‐stress tolerance mechanism in the halophytes and then engineering the genome of glycophytic crop plants for better salt‐stress tolerance. Halophytes grown by seawater irrigation have shown their significance by producing a higher yield of oil and protein‐rich seeds than a conventional oilseed crop, which suggested that the salt‐degraded land can be used for growing halophytes for edible oil or biofuel. Halophytes were also used to restore the wasteland by desalinization and phytoremediation of the heavy metals, used as forage for the cattle and vegetable salads in different parts of the world. The halophyte C. quinoa seeds are rich in minerals and vitamins and gained popularity as mainstream food because of its gluten‐free nature. For improving the salt‐stress tolerance in the crop plants, the current requirement is to understand salt‐stress sensory system at the root, root to shoot signaling, and intracellular sensory and responses at the cell organelles such as chloroplasts, mitochondria, or peroxisomes in halophytes. In halophytes, yet very little is known about the development and functioning mechanism of the EBC or different types of the salt glands. Understanding these mechanisms and engineering, the crop using the genome‐editing approach may improve the salt‐stress tolerance of the crops within a shorter time frame.

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