NaCl胁迫下大麦根系液泡膜H~ -ATPase活性与膜流动性的关系(英文)

用 5 0～ 2 0 0mmol/LNaCl处理 2d后 ,大麦 (HordeumvulgareL .)品种“滩引 2号”(耐盐性强 )根的液泡膜H _ATPase活性增强 ,6 0 0mmol/LNaCl处理下酶活性下降 ;“科品 7号”(耐盐性弱 )在 5 0～ 10 0mmol/LNaCl处理 2d后根的液泡膜H _ATPase活性增强 ,2 0 0～ 6 0 0mmol/LNaCl处理下酶活性随盐浓度增加而降低。 5 0～ 2 0 0mmol/LNaCl处理下“滩引 2号”根的液泡膜流动性下降 ,6 0 0mmol/LNaCl处理下膜流动性明显增大 ;盐胁迫下液泡膜膜脂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。由此推断高盐胁迫下液泡膜膜脂脂肪酸不饱和度上升而引起膜流动性上升可能是引起H _ATPase活性下降的原因之一。

Relationship Between H~ -ATPase Activity and Fluidity of Tonoplast in Barley Roots Under NaCl Stress

H _ATPase activity of tonoplast in roots of Hordeum vulgare L. cv. "Tanyin 2" (salt_tolerant cultivar) increased when the roots were exposed to 50-200 mmol/L NaCl for 2 d, and decreased when NaCl concentration was increased to 600 mmol/L. In "Kepin 7" (salt_sensitive cultivar), tonoplast H _ATPase activity in roots also increased at lower levels of NaCl (50-100 mmol/L), but decreased at higher levels of NaCl (200-600 mmol/L). Tonoplast fluidity in roots of "Tanyin 2" decreased at 50-200 mmol/L NaCl, and increased significantly at 600 mmol/L NaCl. Under salt stress, the change of tonoplast fluidity was identical with that of the ratio of unsaturated fatty acids to saturated fatty acids in tonoplast lipid of barley roots. It is proposed that the increase of tonoplast fluidity due to increased degree of unsaturation of fatty acids is one of the reasons leading to the decrease of H _ATPase activity under higher level of NaCl stress.