干旱胁迫下早熟禾幼苗几种抗旱性指标的变化

Changes of Several Resistance Indexes of the Seedlings of Poa pratensis Under Drought Stress

[目的]探明干旱胁迫下早熟禾幼苗几种抗旱指标的变化规律。[方法]在干旱胁迫期间对早熟禾幼苗植株体内过氧化物酶活性、脯氨酸含量、丙二醛(MDA)含量的变化进行了研究。[结果]在干旱胁迫后期,早熟禾幼苗植株体内过氧化物酶活性、脯氨酸含量均有较高水平增加,有利于其抵抗干旱胁迫。在土壤含水量未达到5.4%前,MDA的含量无显著差异(P>0.05),膜伤害较小;但当土壤含水量降到5.4%时,MDA的含量显著上升。[结论]当土壤含水量降到5.4%时,膜结构遭到破坏,抗逆性下降,是导致早熟禾幼苗干旱死亡的主要原因。

[ Objective ]The research aimed to probe into the influence of the drought stress on several resistance indices related to resistance to drought in the Seedlings of Poa pratensis. [ Method] The activity of POD, the content of MDA and the electric conductivity in the Seedlings of Poa pratensis were investigated under the drought stress. [ Result ] During the drought stress, the activity of POD and the Pro content were remained a higher level which was good to resist the drought stresses, at the same time, before the soil moisture reached 5.4% , no significant differences in content of MDA （P 〉 0.05 ） ,the injmw of membrane was smaller;but when the soil moisture content was 5.4%, a significant increase in the concentration of MDA. [ Conclusion] when the soil moisture content decreased to 5.4% , the structures of membrane was badly destroyed, the major cause of premature death was the decline of the drought resistance which was also the threshold of the seedlings of Pou pratensis under the drought stress.