3种菊科入侵植物不同生长时期的土壤酶活性和养分变化

【目的】黄顶菊、三叶鬼针草和豚草是我国危害较严重的3种菊科入侵植物。了解3种菊科植物生长过程中土壤养分和酶活性的变化,可以为研究其入侵机制提供依据。【方法】在中国农业科学院植物保护研究所廊坊中试基地开展同质园实验,比较分析了黄顶菊、三叶鬼针草和豚草3种菊科入侵植物在幼苗期、旺盛生长期和生殖生长期根际土壤养分和酶活性的变化。【结果】3种外来菊科植物的生长时期对土壤养分和酶活性存在显著影响。3种外来植物入侵域的土壤速效磷、硝态氮含量以及磷酸酶活性随生长时期变化都表现出先升高后降低的趋势,均在旺盛生长期达到最大值。入侵域土壤速效磷和硝态氮含量的变化趋势与狗尾草明显不同。3种外来植物入侵降低了土壤速效钾含量,提高了土壤脲酶、磷酸酶活性。【结论】3种外来菊科植物的入侵改变了土壤养分和酶活性,创造出更有利于自身生长和繁殖的条件,以利于其进一步扩张。

Dynamics of soil enzyme activities and soil nutrients in the rhizosphere at different growth stages of three invasive plants

Aim] Flaveria bidentis (L.) Kuntze, Ambrosia artemisiifolia L. and Bidens pilosa L., three species of exotic plants causing serious damage in China. Understanding the changes in soil nutrients and enzyme activity in the rhizosphere can provide a basis for the study of their invasion mechanism.Method] We compared and analyzed the changes in soil nutrients and enzymatic activities in different growth stages (seedling, vigorous growth stage, reproductive stage) of F. bidentis, A. artemisiifolia and B. pilosa in Langfang Pilot Plant Base, Institute of Plant Protection, Chinese Academy of Agricultural Sciences.Result] The growth stages of all three alien plants had significant effects on soil nutrient and soil enzyme activities. The content of available phosphorus and nitrate, and phosphatase activity in the rhizosphere soil of three invasive plants varied with growth stage (increased first and then decreased), they were maximum in vigorous growth stage. The contents of available phosphorus and nitrate in the invasion area were obviously different from that of the native area in different growth stages. The invasion of all three exotic plants reduced the available potassium content in the soil, and increased the activities of urease and phosphatase in the rhizosphere soil.Conclusion] The registered changes in soil nutrients and enzymatic activity created more favorable conditions for the growth and reproduction of invasives, and facilitated further expansion.