不同生境入侵植物喜旱莲子草碳排放对氮磷输入的响应

Response of carbon emissions from invasive plant alligator weed(Alternanthera philoxeroides)to nitrogen and phosphorus input in different habitats

喜旱莲子草(Alternanthera philoxeroides)的入侵能力极强,可入侵水域和陆地两种生境。采用微宇宙试验方法,在不同生境(水生、陆生)下设置不同氮、磷添加水平模拟养分输入,观测系统内含碳温室气体——甲烷(CH_(4))、二氧化碳(CO_(2))排放,以及生物固碳量的变化,探究不同生境下喜旱莲子草碳排放对氮、磷输入的响应。结果表明,相较于CH_(4),该试验条件下的碳排放以CO_(2)排放为主。在水生生境下,生态系统总体表现为碳汇,且氮、磷添加促进了生态系统的碳吸收;而在陆生生境下,生态系统总体表现为碳排放,且氮、磷添加会促进生态系统的碳排放。因此,评估喜旱莲子草的碳排放时需考虑其入侵生境,以及入侵环境的养分输入状况。

Alligator weed(Alternanthera philoxeroides)is an invasive plant,which could invade both aquatic and terrestrial habitats.In the present study,by using the microcrosmio technique,different nitrogen(N),phosphorus(P)addition levels were set to simulate nutrient input in different habitats(aquatic and terrestrial),and the emissions of carbon-containing greenhouse gases such as methane(CH_(4))and carbon dioxide(CO_(2)),and biomass carbon sequestration were observed in the system,to explore the response of carbon emission from alligator weed to N and P input in different habitats.The results showed that the carbon emission was mainly CO_(2)emission other than CH_(4).In the aquatic habitats,there were mainly carbon sinks,and the N,P addition could promote the carbon sink;while in terrestrial habitats there were carbon emissions,and the N,P input could promote the carbon emissions.Thus,the invasive habitats,as well as the nutrients input status of the invasive site,should be fully considered for the accurate assessment of carbon emissions of alligator weed.