荒漠盐生植物根际土壤酶活性的变化

Dynamics of soil enzyme activity in the rhizosphere of desert halophyte

  • 摘要: 利用根袋法研究了荒漠盐土和灌耕灰漠土中6种不同荒漠盐生植物根际养分和酶活性特征。结果表明: 两种土壤中, 根际土全氮含量比非根际土高, 但全磷却比非根际土低。根际土有效态养分的变化则与全态相反, 6种植物的根际土有效氮含量均显著低于非根际土, 除芦苇外, 根际土有效磷含量均高于非根际土。6种植物中, 钠猪毛菜根际土有效氮亏缺最高, 有效磷富集也最少。分析测定了根际土和非根际土转化酶、蛋白酶、过氧化氢酶、脲酶、中性磷酸酶和碱性磷酸酶活性及其与土壤养分的关系。结果表明: 过氧化氢酶、脲酶和蛋白酶在两种土壤的植物根际表现出相反的变化, 荒漠盐土中, 根际土3种酶的活性均高于非根际土; 而灌 耕灰漠土的根际土3种酶活性均低于非根际土。荒漠盐土碱性磷酸酶、过氧化氢酶和转化酶与几种主要养分含量有很强的相关性, 较好地体现了荒漠盐土根际的养分状况, 也说明盐生植物对荒漠盐土酶活性有较大的 影响。

     

    Abstract: A rhizobag experiment was conducted in desert solonchak and cultivated gray desert soils to investigate nutrient content and soil enzyme activity in the rhizospheres of six desert halophytes. The results show significant increase in total N and decrease in total P in the rhizosphere in comparison with bulk soil. Available N and P have inverse dynamics in that while available N decreases, available P increases, except for Phragmites communis Trin. Available N deficit is highest while accumulated available P is lowest in Salsola nitraria Pall among the six halophytes. Analysis for sucrase, protease, urease, neutral phospherease, alkaline phosphcrease and catalase activity as well as its relationship with soil nutrient content shows inverse dynamics for sucrase, protease and catalase in both soil rhizospheres. In solonchak soils, the activity of the three soil enzymes in the rhizosphere is generally higher than in bulk soils while that in cultivated gray-desert soils are lower. In solonchak soils, the activity of alkaline phosphcrease, catalase and invertase is significantly related with soil nutrient content, which could be a strong indicator of soil nutrient status. The results suggest significant impact of halophyte on enzyme activity in desert solonchak.

     

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