【摘要】 研究了抗旱性不同的2个品种小麦（Triticum aestivum L.）叶片质膜氧化还原系统的部分性质及其在田间缓慢干旱下氧化还原活力的变化。结果显示,2个品种小麦叶片质膜氧化还原活性的最适pH为8.0,最适温度在40℃左右,Mg²⁺对其活性有刺激作用,Ca²⁺对其活性没有影响。但这2个品种叶片的质膜氧化还原系统对K⁺和Na⁺的响应不尽相同:在品种定西24中,K⁺刺激作用不太明显,Na⁺有一定的抑制作用;而在品种8139中,这两种离子都有明显的刺激作用。干旱降低了小麦叶片的水势和水分含量、影响了小麦的生长发育;在缓慢干旱下,小麦叶片质膜氧化还原活力在生长发育的前期上升;在后期,其活性不变或下降,这与前人在实验室内以植物幼苗进行短期而剧烈的模拟干旱下所观察的结果不同。这种差异的原因除了与植物材料不同有关外,主要与胁迫方式及植物的发育阶段有关。更多还原

【Abstract】 Some properties of plasma membrane redox systems in two spring wheat leaves and their responses to gradual field drought were investigated. The results showed that the optimal pH for the redox activity is 8. 0,and the optimal temperature in both wheat leaves is about 40℃. Mg2+ can stimulate their activities, while Ca2+ can’t. But the redox systems in both cultivars have different responses to K+ or Na+. In cv. Dingxi 24,the stimulatory effect of K+ is not significant,and Na+ has an obvious inhibitory effect. While in cv. 8139,both cations can significantly stimulate the redox activity. Drought stress decreased water potential and water content of wheat leaves ,and influenced the plant growth and development. At early developmental stages,drought stress increased the plasma membrane redox activities. While at the late stages, the activities were decreased or not changed. These results were different from those observed on plant seedlings subjected to abrupt simulative drought. The differences might be mainly due to different stress models applied and developmental stages in addition to plant species or cultivars. Our results might be able to help elucidate plant drought resistance under natural drought conditions.更多还原