菊科植物改变土壤氮素的可利用性

Effects of invasive Compositae plants on soil nitrogen content

生物入侵破坏入侵地生态系统的群落结构和稳定性、阻碍农林牧渔业生产、危害人类健康。我国已成为外来生物入侵最严重的国家之一,现有402种入侵植物。菊科、豆科、禾本科构成我国外来入侵植物的主体,其中菊科入侵植物约有107种,广泛分布于我国各省(区)。菊科入侵植物因其独特的生物学特性(如生长发育快、成熟早、种子产量高且易于传播等)而具有高度的入侵性。本文综合分析了国内外38篇共211个关于菊科入侵植物对土壤氮素含量影响的案例。结果发现,菊科植物入侵后,85%以上的案例中土壤总氮、铵态氮、硝态氮等氮素含量显著(P<0.05)增加,其中紫茎泽兰(Ageratina adenophora)对土壤氮素含量的影响最大。菊科植物入侵可通过释放化感物质、分解凋落物和改变土壤氮循环微生物种类和数量来改变土壤氮素含量,从而对本地生态系统的氮养分资源造成极大影响。土壤氮是限制植物生长的最主要因素,通过研究菊科入侵植物对土壤氮素含量的影响能帮助理解土壤氮在入侵过程中的重要作用,促进完善外来植物的入侵机制。

Biological invasion(incursion of invasive species)destroys the community structure and stability of the ecosystem in the invasion area,hinders the production of agriculture,forestry,animal husbandry and fishery sectors,and endangers human health.China has experienced a high degree of biological invasion,with at least 402 species of invasive plants recorded.A majority of these alien invasive plants are in the families Compositae,Leguminosae,and Gramineae.At least 107 of these species,widely distributed in various provinces in China,are species of Compositae,which are characterized by rapid growth,early maturation period,as well as high seed yield with strong dispersal capacity.We comprehensively analyzed the effect of invasive Compositae species on soil nitrogen content in 211 cases from 38 studies.The results showed that Compositae invasion significantly(P<0.05)increased soil nitrogen content,in the form of total nitrogen,ammonium,and nitrate,in more than 85%cases,and that Ageratina adenophora is the species that most affects soil nitrogen.We found that invasive Compositae species changed soil nitrogen content and greatly impacted nitrogen resources in the ecosystem by releasing allelochemicals,decomposing litter,and changing the composition and quantity of soil nitrogen cycling microbes.Considering that soil nitrogen is the most important factor limiting plant growth,reviewing the effect of invasive Compositae species on soil nitrogen content will deepen our understanding of the importance of nitrogen in the process of plant invasion and elucidate the invasion mechanism of alien plants.