Senescence-related lipid changes in callus cultures of Datura innoxia

Abstract

Lipid changes related to abscisic acid (ABA) induced senescence was studied in callus cultures of Datura innoxia. Cultures attained terminal senescence in four weeks due to supplementation of ABA. Senescence was marked by loss of chlorophyll, decrease in protein content and profound changes in lipid composition. Neutral lipids constituted major fraction of cellular lipids together with complete degradation of galactolipids of the senesced callus. In contrast to the phospholipid composition of healthy callus which consisted of phosphatidylcholine (PC) - ethanolamine, - inositol, - serine, - glycerol and phosphatidic acid (PA), the senesced callus had only PE and PC along with their lysoderivatives and PA. The results are discussed in relation to ABA-induced senescence and significance of changes in membrane lipid composition.