Effects of La3+ on ATPase activities of plasma membrane vesicles isolated from Casuarina equisetifolia seedlings under acid rain stress

Abstract

The effects of La3+ on the growth and the ATPases activities of plasma membrane(PM) vesicles isolated from Casuarina equisetifolia seedlings under artificial acid rain(pH 4.5) stress were studied. The results show that the height, length of roots, fresh weight and PM H+-ATPase activites of Casuarina equisetifolia seedlings increase by the treatments of soaking seeds in LaCl3 solutions with lower concentrations, and those can reach their peak values by treating with 200 mg . L-1 La3+. However, in comparison with the CK, those are inhibited by the higher La3+ concentrations; PM Ca2+-ATPase activity is inhibited with the treatments of La3+. The results also reveal that the H+-ATPase activity and the growth of cell enlarge have a remarkable positive correlation, and La3+ activating H+-ATPase can facilitate plant growth. La3+ also can alleviate cytosolic acidification of plant under acid rain stress and indirectly maintain the stability of intracellular environment. In order to resistant to acid rain and accelerate the growth of Casuarina equisetifolia, the suitable range of La3+ concentrations to soak seeds for 8 h is 50 similar to 200 mg . L-1.