干旱条件下冬小麦幼苗根细胞膜脂组成的变化

干旱条件下小麦幼苗根膜脂总脂肪酸含量、磷脂含量及总脂肪酸双键指数均下降，而游离甾醇含量却明显增加，结果导致游离甾醇／磷脂比率上升。用薄层层析法测得小麦根细胞磷脂主要由磷脂酰胆碱(PC)、磷脂酰乙醇胺(PE)、磷脂酰肌醇(PI)及磷脂酸(PA)组成。干旱降低了各种磷脂的含量，但不改变其相对配比。文中讨论了膜脂代谢变化与植物抗旱性的关系。

Changes of Lipid Composition in Root Cell Membranes of Winter Wheat Seedlings Under Drought Stress

In the present study,with two pot-cultured winter wheat cultivars, Qinmai No. 3 and Jinan No. 13,that differ in sensitivity to drought,the effect of drought on the lipid composition of root cell was investigated. Drought was created by withholding water. After 6 days of stress,the content of total acyl lipids measured as total fatty acids and the double bond index of membrane lipids were decreased. Drought stress also decreased phospholipid content drastically,but the relative distribution of individual phospholipids was constant and independent of stress. Free sterol content increased in response to stress. As a consequence the ratio of free sterol/phospholipid increased from 0. 050 and 0.051 of the control to 0. 147 and 0. 120 of the treatment,respectively for cultivars Qinmai No. 3 and Jinan No. 13. These results suggest that root cell membranes of winter wheat seedings respond to drought stress by reducing the degree of lipid fluidity, which would reduce the permeability of the plasma membrane to small molecular substances and help to maintain cell rigidity.