NaCl胁迫下构树幼苗液泡膜生理生化响应(英文)

Physiological and Biochemical Response of Tonoplast Vesicles Isolated from Broussonetia papyrifera to NaCl Stress

以构树幼苗根组织和叶组织为试材,测定不同浓度NaCl胁迫下液泡膜H+-ATPase的活性、液泡膜脂肪酸组成和膜的流动性。结果表明:在低浓度NaCl胁迫下,根组织中液泡膜H+-ATPase的活性有所增加,当胁迫浓度为150mmol·L-1时,活性又有所下降,但接近对照水平。而叶组织液泡膜H+-ATPase的活性在100mmol·L-1时降低,高浓度NaCl(150mmol·L-1)处理后又有所升高。液泡膜脂肪酸基本组成为C16:0,C16:1,C18:0,C18:1,C18:2和C20:0。盐胁迫后构树幼苗液泡膜脂肪酸组分相对含量发生变化。根组织液泡膜脂肪酸不饱和度下降,150mmol·L-1NaCl处理后有所升高;而在叶组织中,液泡膜脂肪酸不饱和度在50mmol·L-1NaCl处理后下降,随着盐胁迫浓度的增加,不饱和度又高于对照。NaCl胁迫下,构树液泡膜流动性和脂肪酸不饱和度的变化趋势相一致。脂肪酸不饱和度下降时,膜流动性下降,反之则膜流动性上升。研究结果为深入了解木本植物液泡膜H+-ATPase活性、脂肪酸组成和膜的流动性在盐胁迫下的适应及其3者的相互关系提供了参考。

The activity of H^＋ -ATPase, fatty acid composition and membrane fluidity of tonoplast vesicles isolated from roots and leaves of Broussonetia papyrifera plantlets under salt stress with different concentrations of NaCl were investigated. The results showed that V-H^＋ -ATPase activity in roots increased at low level of NaCl concentration （50 mmol·L^-1）. When NaCl concentration exceeds 100 mmol·L^-1, the activity was similar with control. In leaves, V-H^＋ -ATPase activity decreased at 100 mmol·L^-1 NaCl, but increased at higher levels of NaCl（150 mmol·L^-1）. It was found that the fatty acid composition of tonoplast was consisted of C16 ： 0, C16 ： 1, C18 ： 0, C18 ： 1, C18 ： 2 and C20 ： 0. Alterations in relative content of tonoplast fatty acid composition under NaCl stress were observed. In roots the extent of unsaturation of tonoplast fatty acids decreased, and then it increased under 150 mmol·L^-1 NaCl. In leaves, the extent of unsaturation of tonoplast fatty acids decreased under 50 mmol·L^-1 NaCl treatment, however the extent increaseal with the increase of salinity, leaves and was higher than that in control. The changes in tonoplast fluidity coincided with those in unsaturation of fatty acids under NaCI stress. Tonoplast fluidity decreased with the decline of unsaturation of fatty acids. The objectives of this study were to gain better understand of the adaptive mechanism of H^＋ -ATPase, fatty acid composition and membrane fluidity of tonoplast of woody plants and their relationship under salt stress.