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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,Mg~(2+)对其活性有刺激作用,Ca~(2+)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。
Part of the plasma membrane redox system of two wheat cultivars with different drought resistance (Triticum aestivum L.) and their changes in redox activity under slow dry conditions were studied. The results showed that the optimum pH of plasma membrane redox activity of wheat leaves was 8.0 and the optimal temperature was about 40 ℃. Mg 2+ stimulated the activity of Ca 2 + No effect. However, the response of plasma membrane redox system to K ~ + and Na ~ + was different in these two cultivars. In cultivar Dingxi 24, K ~ + stimulation was not obvious and Na ~ + was inhibited. In variety 8139, both of these ions have significant stimulatory effects. Drought reduced the water potential and water content of wheat leaves and affected the growth and development of wheat. Under slow drought conditions, the plasma membrane redox activity of wheat leaves increased at the early stage of growth and development and remained unchanged or decreased at the later stage, The results observed under short, intense simulated drought with plant seedlings in the laboratory are different. The reason for this difference is mainly related to the mode of stress and the development stage of the plant, except for the difference of the plant material.