漠境沙打旺根围AM真菌与土壤酶活性的关系

Study on relationships between Arbuscular Mycorrhizal Fungi and soil enzyme activities of Astragalus adsurgens in the desert

【目的】研究漠境AM真菌对宿主沙打旺（Astragalus adsurgens）的作用机理及对根部土壤酶活性的影响。【方法】分别采集陕西靖边、宁夏盐池、内蒙古包头和集宁等4个样地沙打旺根围0～10，10～20，20～30，30～40和40～50CM等5个土层的土壤样品，研究AM真菌在土壤中的空间分布及其与土壤脲酶、蛋白酶、酸性磷酸酶活性和碱解N、速效P含量的关系。【结果】AM真菌定殖率及孢子密度与样地生态条件密切相关，艾中集宁样地孢子密度最高，靖边样地泡囊定殖率最高，包头样地丛枝、菌丝和总定殖率均高于其他样地；孢子密度与AM真菌不同结构定殖率间无显著相关性。土壤酸性磷酸酶活性对孢子密度有极显著正的效应；脲酶活性对孢子密度和丛枝定殖率有极显著的正效应；蛋白酶活性对丛枝定殖率、菌丝定殖率、总定殖率均有极显著正效应。上壤蛋白酶与泡囊定殖率呈显著负相关。碱解氮、速效磷对与以上3种土壤酶活性均旱极显著正相关。【结论】沙漠生境下AM真菌与土壤酶活性显著相关。AM真菌孢子密度和菌根不同结构的定殖程度可作为荒漠土壤生态系统环境状况检测的有效指标。

[Objective] This paper assessed the influences of arbuscular mycorrhizal（AM） fungi on the host plant and compared the response of AM fungi to soil enzymes,i, e. urease,protease and acid phosphatase,and soil factors through analysing desert soil samples. [Method] Soil samples in the rhizosphere of Astragalus adsurgens were collected in 4 replicates and divided a depth of 50 cm into 5 sections,i, e. 0-10, 10-20,20-30,30-40 and 40-50 cm. The author studied 4 sites ：Jingbian （Shaanxi） ,Yanchi （Ningxia） ,Baotou （Inner Mongol）,and Jining （Inner Mongol）. With the samples of the roots, the distributions of AM fungi were observed and the relationships with soil enzymes were analyzed. [Result] The results showed that AM fungi and soil enzymes had salience correlations. AM fungal colonization and spore density had a similar dynamic variation which declined with soil depth. The spore density from Jining was the highest of all of the samples, just as the vesicular colonization of Jingbian was higher than that of other samples. Arbuscular colonization from the samples of Baotou, as well as the hyphal and total colonization,was much higher than that of other areas. But between the spore density and colonization, there was not enough correlation.Furthermore,higher soil acid phosphatase and soil urease tended to be correlated with higher spore density. Soil urease and protease might have a significant effect on arbuscular colonization. Soil protease also had a positive correlation with hyphal and total colonization. Different from other colonization, vesicular coloni- zation had a negative correlation with soil protease. In contrast,available N and available P had a positive correlation with soil enzymes. [Conclusion] The results also advised that soil enzymic activities were strongly correlated to AM fungi in desert ecosystem,and that the soil spore density and the distribution of AM fungal colonization were useful indicators for the building and perfecting of index evaluation system of desert soil ecosystem.