Effects of high night temperature on lipid and protein compositions in tonoplasts isolated from Ananas comosus and Kalanchoë pinnata leaves

Effects of high night temperature on the lipid and protein compositions in the tonoplasts isolated from the leaves of two Crassulacean acid metabolism (CAM) plants, Ananas comosus (pineapple) and Kalanchoë pinnata were studied. The results showed that the phospholipids/protein ratios in the tonoplasts isolated from pineapple and K. pinnata leaves decreased from 1.82 to 1.21 and 2.63 to 1.50, respectively, as the night temperature increased from 20 to 37°C. Under high night temperature, relative amount of total unsaturated fatty acids in K. pinnata was increased by 6 %, which was mainly caused by increased C18:2 and C18:3, whereas unsaturated fatty acids, C18:2 and C18:3 in pineapple did not show significant change. The distribution patterns of tonoplast proteins in the two CAM species were different between normal and high night temperature and in K. pinnata, especially those with molecular mass ranging from 66.2 to 97.4 KDa. Compared with normal night temperature, more proteins were found in pineapple, but no difference was found in K. pinnata. Thus, above result indicated that the pineapple tonoplasts could keep higher rigidity under high night temperatures compared to the K. pinnata.