Chlorine Nutrition of Higher Plants: Progress and Perspectives

Chlorine (Cl) occurs predominantly as Cl- in soil and plant. It is an essential micronutrient of higher plants and participates in several physiological metabolism processes. Its functions in plant growth and development include osmotic and stomatal regulation, evolution of oxygen in photosynthesis, and disease resistance and tolerance. At adequate levels of supply, Cl improves the yields and quality of many crops such as onions and cotton if the soils are deficient in this nutrient. When excessive, Cl can be as a major component of salinity stress and toxic to plants. This paper provides a brief review of current progresses on Cl nutrition of higher plants.