盐胁迫下芦荟叶同化组织细胞中ATP酶活性超微结构定位及Si的作用

 利用电镜―细胞化学技术研究了盐胁迫下芦荟（Aloe vera L.）叶同化组织细胞中ATP酶（ATPase）分布特性及外源硅（Si）的作用。结果表明，正常生长情况下，芦荟叶同化组织细胞中液泡膜ATPase活性明显强于质膜ATPase，在细胞壁初生纹孔场观察到很强的ATPase活性。NaCl 100 mmol·L^-1处理30 d，浇灌的营养液中不加可溶性Si，芦荟叶同化组织细胞中液泡膜、质膜和初生纹孔场ATPase活性显著减弱，浇灌的营养液中加Si 2.0 mmol·L^-1处理，芦荟叶同化组织细胞中ATPase活性则显著增强，尤其是在液泡膜和初生纹孔场。叶同化组织细胞中ATPase活性的差异性反映着芦荟叶生理状态和功能的差异性，可溶性Si调节或增强盐胁迫下芦荟ATPase活性是Si缓解芦荟盐胁迫伤害效应的重要细胞生理机制。

Ultrastructural Localization of ATPase Activity in Cells of leaf Chlorenchyma of Aloe vera L. under Salt Stress and the Effect of Silicon

Ultrastructural localization of ATPase activity in cells of leaf Chlorenchyma of Aloe vera L. under NaCl stress with or without Si addition were investigated by electron-microscopy-cytochemical technique. The results showed that ATPase activities, indicated by the status of cerium phosphate (CePO₄) precipitated products, were mainly localized in primary pit field and tonoplast of chlorenchyma cells of aloe seedlings irrigated with Hoagland's solution, next was in plasma membrane. Treated with 100 mmol·L^-1 NaCl without added Si for 30 d, ATPase activities in primary pit field, plasma membrane and tonoplast of the cells were all significantly decreased. Nevertheless, irrigated with 100 mmol·L^-1 NaCl with 2.0 mmol·L^-1 added Si, ATPase activities in these apartments of the cell were significantly enhanced, particularly in tonoplast and primary pit field. Based on results in this study and our previous findings, we believe that differences of ATPase activity in cells of aloe leaf Chlorenchyma reflect the differences of physiological status and function of aloe leaves, regulating and/or enhancing ATPase activity is an important cyto-physiological mechanism of Si-alleviated effect on salt injury to aloe.