Review of Genotypic Differences and Underlying Mechanisms in Potassium Efficiency of Cotton(Gossypium hirsutum)

Potassium(K) is a major plant nutrient with many biochemical and physiological functions.Cotton has a high demand for K.However,widespread K deficiency in cotton occurs in many countries.Cotton varieties differ in their K uptake efficiency.This review accessed the available literature on K uptake and utilization efficiency in cotton related to genotype differences.Genotypes efficient in K uptake may have a larger root system and/or efficient physiological uptake characteristics(such as greater Imax [maximum influx rate],and lower Km [the Michaelis constant] and Cmin [the minimum concentration for net uptake]).Furthermore,genotypes efficient in K utilization may have active K transport and remobilization,high net photosynthetic ability,better balance between carbon and nitrogen metabolism,greater ability to scavenge reactive oxygen species,and increased capacity to substitute Na+ for K+.Future research areas regarding K efficiency in cotton are suggested.