Abstract

The role of plasma membrane H+-pumping ATPase in the tolerance to salt stress of soybean plants were studied in the present study. Salt-acclimated plants which had previously acclimated to salt-stress condition accumulated higher concentration of Na+ in root cells than that of the control and non-acclimated plants. The level of Na+ accumulation in root cells correlated with the inside-acid proton gradient (ΔpH) across the plasma membrane vesicles. The salt-acclimated plants had higher antiport activity of Na+ influx /H+ efflux and H+-pumping ATPase activity than that of control and non-acclimated plants. It may be concluded that higher H+-ATPase activity favored salt-acclimated plants growing under the salt-stress environment.

中文摘要

大豆幼苗分成三個實驗組，即對照組、鹽逆境馴化組、及未馴化組。馴化組植物的根細胞中Na+有累積的現象，其細胞中所含Na+濃度均比對照組及未馴化組植物高。Na+的累積受到細胞膜內外的氫離子濃度梯度所影響，因為馴化組植物比其他兩組植物具有較高的氫離子濃度梯度以及較高Na+/H+的互換輸送活性。細胞膜內外的氫離子濃度梯度的形成受到膜H+-ATPase活性所調控，而馴化組植物比其他倆組植物也具有較高的H+-ATPase活性, 因此可歸納而言，高H+-ATPase活性對植物耐監性有重大的影響。 關鍵詞：細胞膜，H+-ATPase，氫離子梯度，螢光，鹽馴化，鹽累積，大豆。

Keyword: Plasma membrane, Proton- pumping ATPase, Proton gradient, Fluorescence, Salt-acclimation, Salt accumulation, Soybean.