Crop Adaptability to Excess Salt

Abstract

High salt concentration in arable soil/soil salinization poses an increasing agricultural problem all over the world. Such salt accrual is resulting from the sea water mixing with irrigation supply and naturally high content of salts in water used for agricultural irrigation. Further, concerning plants, the stress generated by salt salinization of the soil can be divided into two stages: (i) early osmotic imbalance disturbing water uptake by the plant roots and (ii) the stress created by Na⁺ and Cl⁻ ions that disturb the metabolism together with the productivity of photosynthesis. Plants moderate these stresses by developing certain mechanisms for enhancing water retention (decrease in the loss of water with increase in its uptake) and preventing the detrimental effects of Na⁺ ions by their vacuolar entrapment together with exclusion from the tissues of the leaves. However, even after employing the tolerant mechanisms, plants are adversely affected, and this is specially observed as a decrease in crop productivity/yields that ultimately resulting in continuous decrease in arable land resources. Factors of rapid expansion of population size and continuously improving quality of life are exerting a great pressure upon the agriculture resources. Therefore, managing the salt stress in agricultural plants and developing varieties with such mechanisms can play a pivotal role in addressing the challenge of rapidly increasing demand of agribusiness. This chapter focuses on the mechanisms of salt tolerance in plants, sensory, and signaling networks associated with salinization, Na⁺ transport, gene expression regulatory responses toward salt stress, and the approaches toward designing salt tolerant crops.