Potassium and stress alleviation: Physiological functions and management of cotton

Potassium (K) plays a major role in the basic functions of plant growth and development. In addition, K is also involved in numerous physiological functions related to plant health and resistance to biotic and abiotic stress. However, K deficiency occurs widely resulting in poor growth, lost yield, and reduced fiber quality. This review describes the physiological functions of K and its role in stress relief and also provides some agronomic aspects of K requirements, diagnosis of soil and plant K status, and amelioration. The physiological processes described include enzymes and the regulation of organic‐compound synthesis, water relations and stomates, photosynthesis, transport, cell signaling, and plant response to drought stress, cold stress, salt stress, as well as biotic stresses. The agronomic aspects of K fertilization include the K requirements of cotton, K uptake, and soil characteristics, genotypic variation in K uptake and use, and characteristics of K deficiency in cotton. In addition, diagnosis and amelioration of K soil and plant status is discussed.