盐胁迫下La^(3+)和Eu^(3+)对小麦质膜能化系统活性的影响

Effects of La^(3+) and Eu^(3+) on the Activities of Energizing System of Plasma Membrane in Wheat Seedling under Salt Stress

两相法分离纯化小麦(Triticum sativum L)根细胞质膜微囊用于测定La3+和Eu3+对质膜H+-ATPase及氧化还原系统活性的影响。结果显示,200mmol/L NaCl溶液处理显著抑制了小麦幼苗根细胞质膜H+-ATPase活性及NADH氧化速率和Fe(CN)63-还原速率;适宜浓度La3+和Eu3+处理使盐胁迫下小麦活体根细胞质膜H+-ATPase及氧化还原系统活性明显提高;不同浓度稀土离子处理对离体细胞中H+-ATPase活性均表现出了抑制作用。两种稀土离子对活体和离体细胞质膜H+-ATPase具有不同的生理学效应。这些结果将有助于阐明盐胁迫条件下稀土元素提高植物耐盐能力的生理机制。

Highly purified plasma membrane vesicles were isolated by aqueous twophase partitioning from wheat （Triticum sativum L） seedling roots, and then the activities of H^＋ -ATPase and redox system in plasma membranes were determined. The results show that 200 mmol/L NaCl significantly inhibited the activities of H^＋ -ATPase and oxidation rate of NADH and reduction rate of Fe（CN）6^3-. Low concentrations of La^3＋ and Eu^3＋ could increase the activities of H^＋ -ATPase and redox system significantly, whereas high concentrations of La^3＋ depress them. In contrast to results in vivo, all concentrations of La^3＋ and Eu^3＋ inhibited the activity of H^＋ -ATPase of plasma membrane vesicles in vitro. The two rare earth elements ions present different physiological effects on H^＋ -ATPase activities of plasma membranes of wheat seedling in vitro and vivo. To some extent, these results would reveal the physiological mechanism how rare earth elements enhance the salinity tolerance of plants under salt stress.