Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China.
Department of Urban Construction Engineering, Guangzhou City Polytechnic, Guangzhou, China.
Ann N Y Acad Sci. 2020 Jun;1470(1):57-66. doi: 10.1111/nyas.14330. Epub 2020 Mar 13.
Plant-plant interaction is essential to weed invasion success and is related to impacts on the environment. To understand interactions of the well-known invasive plant siamweed (Chromolaena odorata) and its neighbors (exotic Praxelis clematidea and native cadillo) in South China, and their competitive mechanisms above- and belowground, a multicultivation experiment was conducted. Competitive indices, plant morphological traits, soil nutrient contents, enzyme activities, and microbial biomass were measured. Competitive balance index and morphological traits revealed balanced competition between P. clematidea and siamweed, and suppressive effect of siamweed on cadillo. In coculture of siamweed and P. clematidea, the branch length of siamweed slightly lengthened, while the branch number of P. clematidea increased compared with their respective monocultures accordingly. Overall impacts of the two invaders on soil properties were near averages of their single impacts. In coculture of siamweed and cadillo, siamweed was more competitive in both light and nutrient capture; soil urease activity and acid phosphatase activity were magnified and mitigated compared with the averages of those in their respective monocultures, respectively. The species-specific results of siamweed competing with its co-occurring weeds would contribute to a better understanding of mechanism in synergistic effect of siamweed with the other invasive plants.
植物-植物相互作用对于杂草入侵的成功至关重要，并且与对环境的影响有关。为了了解华南地区广为人知的入侵植物暹罗草（Chromolaena odorata）与其邻居（外来的 Praxelis clematidea 和本地的 cadillo）之间的相互作用及其地上和地下的竞争机制，进行了多培养实验。测量了竞争指数、植物形态特征、土壤养分含量、酶活性和微生物生物量。竞争平衡指数和形态特征表明，P. clematidea 和暹罗草之间存在平衡竞争，暹罗草对 cadillo 具有抑制作用。在暹罗草和 P. clematidea 的共培养中，暹罗草的分枝长度略有延长，而 P. clematidea 的分枝数相应增加，与各自的单培养相比。这两种入侵植物对土壤性质的总体影响接近它们各自单一影响的平均值。在暹罗草和 cadillo 的共培养中，暹罗草在光和养分捕获方面更具竞争力；与各自的单培养相比，土壤脲酶活性和酸性磷酸酶活性分别放大和减轻。暹罗草与其共生杂草竞争的特定物种结果将有助于更好地理解暹罗草与其他入侵植物协同作用的机制。
