CHILLING INJURY IN COTTON (GOSSYPIUM-HIRSUTUM-L) - PREVENTION BY ABSCISIC-ACID

Cotton (Gossypium hirsutum L.) intact seedlings and isolated cotyledonary discs were exposed to chilling (4°C) under humid conditions which prevented dehydration. The damage resulting from chilling was estimated by means of electrolyte leakage and survival in whole seedlings and by the electrolyte leakage and necrotic areas in isolated cotyledonary discs. Also, the effect of chilling on membrane phospholipids and cellular reduced glutathione was determined. Within the first two and three days of chilling, there was a marked reduction in the reduced glutathione and membrane phospholipid levels without electrolyte loss and necrosis. This reduction was completely prevented by pretreatment with abscisic acid. Prolonging the chilling period resulted in decreased survival in whole seedlings and in progressive increase in electrolyte leakage and necrosis in isolated cotyledonary discs. Pretreatment with abscisic acid prior to chilling almost completely prevented this chilling injury when exposure to 4°C was less than 5 days. Even with longer chilling periods, the abscisic acid pretreatment greatly reduced the damage. © 1979 Oxford University Press.