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紫茎泽兰(Ageratina adenophora)是我国西南热带亚热带地区危害最严重的外来入侵植物之一。本研究在野外设置不同氮肥供给水平和种植密度下的紫茎泽兰、拔毒散(Sida szechuensis)、伏生臂形草(Brachiaria decumbens)和非洲狗尾草(Setaria anceps)的单种和紫茎泽兰与其他3种植物混种的人工群落,从植被-土壤相互作用的角度分析紫茎泽兰的入侵机制。结果表明:单种时4种受试植物均表现了对氮营养的响应,随氮肥水平的升高,根冠比降低,比叶面积升高;通过比较总生物量增幅,氮响应能力非洲狗尾草>伏生臂形草>紫茎泽兰>拔毒散。混种时受试植物与紫茎泽兰的生物量比和株高也表明非洲狗尾草的竞争能力>伏生臂形草>紫茎泽兰>拔毒散;与拔毒散混种的紫茎泽兰以及与紫茎泽兰混种的伏生臂形草和非洲狗尾草的种内竞争随种植密度的增大而增大,导致种间竞争能力下降,在高种植密度下对混种物种的抑制作用减弱。紫茎泽兰在氮响应能力、竞争能力和表型可塑性方面均强于本地种,可能与其入侵机制有关;牧草的氮响应能力和竞争能力强于紫茎泽兰,其中非洲狗尾草又强于伏生臂形草,可能更适宜于入侵地的替代控制。
Ageratina adenophora is one of the most invasive alien plants in the tropical and subtropical regions of southwest China. In this study, single and purple stems of Eupatorium adenophorum, Sida szechuensis, Brachiaria decumbens and Setaria anceps were set up in the field under different nitrogen supply levels and planting densities. In order to understand the invasion mechanism of Eupatorium adenophorum from the perspective of vegetation-soil interaction, the artificial mixed community of Orchidaceae and other three species of plants was analyzed. The results showed that all the four tested plants showed the response to nitrogen nutrition. When the nitrogen level increased, the root / shoot ratio decreased and the specific leaf area increased. By comparing the total biomass increment and nitrogen response ability, > Brachiaria grass> Eupatorium adenophorum> Detoxification powder. The biomass and plant height of test plants and Eupatorium adenophorum also showed that the competition ability of Setaria viridis> Braconidae> Eupatorium adenophorum> Detoxification powder; The intraspecific competition between Zeelanda and Aegothecua Boletus mixed with Aegilops tauschii and F. viridis increased with increasing planting density, resulting in a decrease in interspecific competition, increasing interspecies competition at high planting densities The inhibition is weakened. Eupatorium adenophorum is stronger than native species in response to nitrogen, competitive ability and phenotypic plasticity, and may be related to its invasion mechanism; forage response to nitrogen and competitive ability stronger than Eupatorium, which is superior to Volatile Brachiaria grass may be more suitable for alternative control of the invasion.