CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones & Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; South China National Botanical Garden, Guangzhou 510650, China; University of Chinese Academy of Sciences, Beijing 100049, China.
CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones & Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; South China National Botanical Garden, Guangzhou 510650, China.
Sci Total Environ. 2024 Nov 10;950:175196. doi: 10.1016/j.scitotenv.2024.175196. Epub 2024 Aug 2.
Invasive plants can change the community structure of soil ammonia-oxidizing microbes, affect the process of soil nitrogen (N) transformation, and gain a competitive advantage. However, the current researches on competition mechanism of Chromolaena odorata have not involved soil nitrogen transformation. In this study, we compared the microbially mediated soil transformations of invasive C. odorata and natives (Pisonia grandis and Scaevola taccada) of tropical coral islands. We assessed how differences in plant biomass and tissue N contents, soil nutrients, N transformation rates, microbial biomass and activity, and diversity and abundance of ammonia oxidizing microbes associated with these species impact their competitiveness. The results showed that C. odorata outcompeted both native species by allocating more proportionally biomass to aboveground parts in response to interspecific competition (12.92 % and 22.72 % more than P. grandis and S. taccada, respectively). Additionally, when C. odorata was planted with native plants, the available N and net mineralization rates in C. odorata rhizosphere soil were higher than in native plants rhizosphere soils. Higher abundance of ammonia-oxidizing bacteria in C. odorata rhizosphere soil confirmed this, being positively correlated with soil N mineralization rates and available N. Our findings help to understand the soil N acquisition and competition strategies of C. odorata, and contribute to improving evaluations and predictions of invasive plant dynamics and their ecological effects in tropical coral islands.
入侵植物可以改变土壤氨氧化微生物的群落结构，影响土壤氮（N）转化过程，并获得竞争优势。然而，目前关于假臭草竞争机制的研究还没有涉及土壤氮转化。本研究比较了热带珊瑚岛入侵植物假臭草和本地植物（海杧果和水芫花）的微生物介导的土壤转化。我们评估了植物生物量和组织 N 含量、土壤养分、N 转化速率、微生物生物量和活性以及与这些物种相关的氨氧化微生物的多样性和丰度的差异如何影响它们的竞争力。结果表明，假臭草通过响应种间竞争将更多比例的生物量分配到地上部分，从而与本地物种（比海杧果和水芫花分别多 12.92%和 22.72%）竞争。此外，当假臭草与本地植物一起种植时，假臭草根际土壤中的有效氮和净矿化率高于本地植物根际土壤。假臭草根际土壤中氨氧化细菌的丰度更高，这与土壤氮矿化率和有效氮呈正相关。我们的研究结果有助于了解假臭草的土壤 N 获取和竞争策略，并有助于提高对热带珊瑚岛入侵植物动态及其生态影响的评估和预测。
