沿绿洲-荒漠过渡带水分梯度分布的芦苇抗氧化保护机理

对甘肃省河西走廊绿洲-荒漠过渡带沿水分梯度分布的芦苇的生长环境特征以及抗氧化系统特征的研究结果表明,芦苇叶片脂质过氧化产物丙二醛(MDA)含量在盐渍胁迫严重的盐渍化生境很高。芦苇叶片超氧化物歧化酶(SOD)活性在根区土壤含水量降低时显著增加,对抵御干旱胁迫的贡献较大,但对盐渍胁迫并不敏感;抗坏血酸过氧化物酶(APX)和过氧化氢酶(CAT)的活性随干旱胁迫加剧而逐渐升高,对水分亏缺的响应大于对盐渍化响应;过氧化物酶(POD)活性在土壤含水量较高的盐渍化生境和土壤含水量很低的沙丘生境中都较高,对抵抗盐渍胁迫和干旱胁迫起着同样重要的作用。芦苇叶片抗氧化物质类胡萝卜素(Car)含量随土壤含水量降低未表现出显著变化,在盐渍化生境还有降低,说明Car对抵御干旱胁迫和盐渍胁迫贡献很小。

The mechanism of antioxidative protection in Phragmites communis under the gradient of soil water content along the oasis-desert transitional area

The characteristics of habitats and antioxidation systems in Phragmites communis were investigated along the oasis-desert transitional area in the Hexi Corridor of Gansu Province.The results showed that MDA content in P.communis leaves were higher in saline habitats.The SOD activities in P.communis leaves increased rapidly when soil water content of the root region was lower than the soil salt content,which suggests SOD is important for resistance to drought stress.The activities of APX and CAT increased gradually as drought stress became more and more severe implying that the response of APX and CAT to drought stress was more positive than that to saline stress.The POD activities were high in both the saline and dune habitats,indicating that POD plays a major role in resistance to drought and saline stress in oxidative defence systems of P.communis.There was no significant variation in Car content in P.communis leaves with a decrease of soil water content of the root region,but a minor decrease occured with an increase of soil salt content indicating that the role of Car was small against drought and saline stress.