不同方式的水分胁迫对小麦幼苗生理的影响

以抗旱性不同的两个冬小麦品种为材料，研究了其幼苗在ＰＥＧ模拟的不同水分胁迫条件下，几个生理指标的变化，结果表明：在慢速水分胁迫条件下，抗旱性强的品种，初期叶片ＲＷＣ下降幅度很少，质膜相对透性、脂质过氧化水平均略低于对照，ＳＯＤ活性增加较多，抗旱性弱的品种其ＲＷＣ下降幅度较大，质膜相对透性，脂质过氧化水平均高于对照，ＳＯＤ活性增加较少，且抗旱性强的品种ＳＯＤ对水分亏缺敏感，随着胁迫强度的增加，伴随叶

Effects of Low-Speed and Rapid-Speed Water Stress on Several Physiological Indexes in Winter Wheat Seedlings

Several physiological indexes in two different drought-resistant winter wheat seedlings under PEG induced low-speed and rapid-speed water stress were studied in this paper. In the primary stage of lowspeed water stress,there is a reaction-harding phase, in this phase, the leaf RWC decreased less. membrane permeability and level of lipid perioxidation were lower than those of the control,activity of SOD increased more and SOD was sensitive to water stress in the drought-resistant cultivar compared with the drought-sensitive cultivar. In the latter stage of low speed water stress, the leaf RWC decreased more, the SOD activity,membrane permeability and level of lipid perioxidation were still increasing. But differences between the two wheat cultivars existed.RWC decreasis was less, membrane permeability and level of lipid perioxidation increased less,SOD activity increased more in the drought-resistant cultivar,the changes in the drought-sensitive cultivar were on the countrary. Under rapid speed water stress,with the intense decreasis of leaf RWC,the membrane permeability and level of lipid perioxidation increased largely,but SOD activity increased a little. The differences between the two wheat cultivar were not significant because the intensity of the water stress exceeded the ability of adaptation of the wheat seedlings to water stress.