摘要
以两相法纯化的小麦（TriticumsativumL．）根质膜微囊为材料，研究了渗透胁迫下质膜物理状态的变化。结果表明，随着介质蔗糖浓度增加，质膜光散射值降低，二苯己三烯（DPH）荧光偏振值升高，MC540荧光强度增强，并且DPH长寿命组分的荧光寿命和平均寿命都缩短，暗示渗透胁迫使质膜微囊收缩变小，降低了质膜流动性和表面电荷密度，并且表明质膜的疏水性减弱。进一步实验发现，质膜内源色氨酸长寿命组分的寿命缩短，质膜H+－AT－Pase活力降低，暗示膜蛋白的构象和功能发生了改变。结果表明，质膜膜脂物理状态改变可能是植物感受渗透胁迫的原初响应。
The plasma membrane vesicles were purified from wheat (Triticum sativum L. ) roots by the twophase paltitioning method. The results showed that with the increase in sucrose concentrations, light scatteringwas decreased, diphenyl hexatriene (DPH) polarization and meroeyanine 540 (MC540) fluorescence intensityincreased, indicating that under osmotic stress the vesicles were getting smaller, the membrane fluidity andsurface charge density were decreased. Further experiments showed that the long lifetime and average lifetimeof DPH fluorescence decreased under stress, suggesting that plasma membrane hydrophobicity decreased. Thelong lifetime fluorescence of intrinsic tryptophan was also decreased, indicating that the polarity of the microenvironment surroundirg the tryptophan was increased, i. e. protein conformation changed; It was also found thatthe H+ -ATPase activity decreased with the increase in sucrose concentrations, suggesting that the membraneprotein function was also affected by the physical state under osmotic stress.
基金
国家自然科学基金!3977077
关键词
小麦
根
质膜微囊
物理状态
渗透胁迫
Wheat roots, Plasma membranes, Physical state, Osmotic stress
