白刺花(Sophoraviciifolia)适应土壤干旱的生理学机制

Physiological mechanism of Sophoraviciifolia to adapt to soil drought

用盆栽的方法人工控制土壤干旱条件,研究白刺花天然实生幼苗适应土壤干旱的生理学机制。结果表明:随土壤含水量的减少,白刺花叶水势在胁迫前期下降缓慢,随胁迫时间的延长,水势大幅度下降。白刺花通过在叶片内积累大量渗透保护性物质可溶性糖和K+,增加细胞的保水力,维持细胞生长所需膨压。白刺花游离脯氨酸含量变化与水分关系不大,可溶性蛋白质含量随土壤含水量减少而下降,可能是水分胁迫下受伤害的表现。随土壤水分含量的减少,白刺花SOD的活性明显升高,POD活性不高但随胁迫时间延长其活性较稳定,CAT活性下降但幅度不大,且CAT活性变化趋势与POD活性相反,说明三个保护酶能够相互配合协同作用,降低膜脂过氧化程度,减少水分胁迫造成的伤害,提高质膜稳定性,维持细胞膜的完整性,表现出很强的抗旱适应性。

With pot culture experiments simulating different soil drought, physiological mechanism of Sophoraviciifolia seeding to adapt to soil drought was studied. The result showed that water potential of Sophoraviciifolia decreased slowly in the early stage of stress and the soil water content and later water potential decreased sharply with time. It accumulated much osmotic regulating substances (soluble sugar, K^+) to increase leaf water retaining capability and maintain growth turgor. It was not related to Pro change and siol water. Soluble sugar content decreased with soil water decrease and it could be injured under soil drought. SOD activity rose significantly and POD activity keptstable with stress time and CAT activity decreased. Change trend of CAT was not same as that of POD. It demonstrated that three-cell defense enzymes could cooperate to reduce lipid peroxidation degree, decrease cell wound, promote protoplasm membrane stability and maintain cell membrane integrity. Sophoraviciifolia has stronger drought resisting adaptability.\;