低温、高pH胁迫对水稻幼苗根系质膜、液泡膜ATP酶活性的影响

以耐冷性不同的两个水稻品种为材料，比较研究了幼苗根系质膜、液泡膜ATP酶对低温(8℃)及高pH(8.0)胁迫的反应。结果表明水稻根细胞质膜和液泡膜上均存在Ca3+-ATP酶，但活性远低于H+-ATP酶。耐冷品种武育粳3号经低温(8℃)处理2d,根系质膜和液泡膜H+-ATP酶、Ca2+-ATP酶活性均明显升高，至冷处理12d,H+-ATP酶、Ca2+-ATP酶活性有所下降，但仍与对照相近；而冷敏感品种汕优63经低温(8℃)处理2d,根系质膜H+-ATP酶活性略有升高，而质膜Ca2+-ATP酶以及液泡膜H+-ATP酶、Ca2+-ATP酶活性已明显下降；至冷处理12d,4种酶活性均明显低于对照。高pH胁迫使质膜和液泡膜H+-ATP酶活性下降，而使Ca2+-ATP酶活性上升。高pH胁迫会加剧低温冷害。结果表明，耐冷品种质膜、液泡膜ATP酶比冷敏感品种对低温胁迫有更强的适应能力。

Effects of Chilling and High pH Stresses on the ATPase Activities of Plasma Membrane and Tonoplast Vesicles Isolated from Rice (Oryza sativa L.) Roots

The ATPase activities of plasma membrane (PM) and tonoplast (TP) vesicles from chilling-sensitive and chilling-insensitive rice (Oryza sativa L.) roots were investigated under low temperature and high pH stresses. The results showed that Ca2+-ATPase were present in PM and TP of rice roots, but their activities were much lower than those of H+-ATPases (Figs.1～4). For chilling-insensitive rice (Wuyujing-3) roots, the PM and TP H+-ATPase and Ca2+-ATPase activities increased significantly after 2 d at 8℃, and after 12 d, their activities were similar to the control (20℃, pH 5) ( Figs. 1～4). For chilling-sensitive rice (Shanyou-63) roots, 2 d after low temperature (8℃), the PM H+-ATPase activity increased only slightly (Fig.1), whereas PM Ca2+-ATPase and TP H+-ATPase, Ca2+ ATPase activities were lowered very much after 12 d under chilling (8℃) stress (Figs.2～4). High pH (8.0) stress resulted in decreases in PM and TP H+-ATPase activities, but an increase in Ca2+-ATPase activity. High pH stress made chilling injury more serious. To sum up, the PM and TP ATPases in chilling-insensitive rice roots showed a higher adaptability to low temperature stress than those in chillinginsensitive ones.