7. Mechanism of Chilling Injury in Plants(Lectures presented at the Seminar of Japanese Society for Research of Freezing and Drying : "Low Temperature and Living Organisms")

Abstract

Many plant species indigenous to tropical and subtropical low lands are sensitive to chilling environment. Protracted exposure to low temperatures ranged above zero to 12℃ leads eventually cell death, although the cell injury is reversible at the initial stage. In mung bean seedlings, vacuolar membranes are found to be the most sensitive cellular site for chilling temperature. Dysfunction of the vacuolr proton pumps under low temperature due to the strong temperaturedependency of the enzymes and the time-dependent inactivation of the H^+-ATPase appears to cause the leakage of protons from vacuoles and leads an acidosis of the cytoplasms in the initial stage of chilling treatment, which is considered to be a determinant of cell injury.