硅改善盐胁迫下库拉索芦荟生长和离子吸收与分布

Si2．0mmol／L处理明显缓解NaCl 100、200mmol／L胁迫120d对库拉索芦荟（Aloevera）生长的抑制作用。Si可显著降低NaCl胁迫下芦荟植株中的Na^＋和Cl^-含量，提高K^＋含量，从而显著降低K^＋／Na^＋，促进根对K^＋的选择性吸收（ASK,Na）和K^＋向地上部的选择性运输（TSK,Na），以维持植株体内的离子稳态。根系和叶片横切面的X-射线能谱微区分析结果进一步证实了这一结果。Si改善盐胁迫下芦荟对K^＋的选择性吸收和运输的机制之一是通过显著提高盐胁迫下芦荟根细胞质膜H^＋ATPase、液泡膜H^＋-ATPase和液泡膜H^＋-PPase的活性。

Silicate Improves Growth and Ion Absorption and Distribution in Aloe vera under Salt Stress

Si 2.0 mmol/L in irrigation solution alleviated significantly the inhibition of NaCl stress of 100 or 200 mmol/L to aloe growth. Exogenously applied Si decreased significantly Na(+) and Cl(-) contents, increased K(+) content and K(+)/Na(+) ratio and selectivity ratio of absorption (AS(K, Na)) and of translocation (TS(K, Na)) to K(+) and Na(+) in aloe plant under both NaCl 100 and 200 mmol/L stresses for 30 d. In this way, the ion homeostasis in aloe plant under NaCl stress was maintained, as was proved by X-ray microanalysis of root tip and leaf across sections. One of the mechanisms to achieve this may be the significant enhancement of H(+)-ATPase activities by the addition of silicate in plasma membrane and tonoplast, H(+)-pyrophosphatase (H(+)-PPase) activity in tonoplast isolated from aloe root tips under NaCl stress.