The rise in atmospheric CO₂ levels is foreseen to enhance the growth of exotic invasive plants and potentially alter the rhizosphere microbial community, which in turn could enhance the risk of colonization by such invaders. This response could be determined by the plant type and the features of invaded soil. The goal of this investigation was to compare the effects of elevated CO₂ on the rhizosphere bacterial and fungal communities of two invaders with distinct degrees of invasiveness, Nicotiana glauca and Mirabilis jalapa, by growing the plants in five different semiarid soils at ambient (410 ppm) or elevated (760 ppm) CO₂. The changes in soil physicochemical, biochemical, and biological features mediated by the invaders were also evaluated. The effect of CO₂ supply on shoot dry biomass was only significant for N. glauca, the shoot and root biomass of plants grown under elevated CO₂ being approximately 53% and 14% greater, respectively, than those of the plants grown under ambient CO₂. Elevated CO₂ only promoted shifts in the rhizosphere bacterial community composition and enhanced the bacterial functional potential related to nucleoside and nucleotide biosynthesis and N-cycling in N. glauca. Among the bacterial indicator species, the genera Sphingomonas, Stenotrophobacter, and Gaiella were more abundant in the rhizosphere of N. glauca plants grown under elevated CO₂. This study demonstrates that the responses of aboveground and belowground biomass of invasive plants to CO₂ enrichment, as well as those of the composition and functioning of soil microbial communities, are dependent on their degree of invasiveness.

中文翻译：

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升高的 CO2 对半干旱地中海土壤中根际微生物群落和两种入侵植物的生长有不同的影响

预计大气 CO ₂水平的上升会促进外来入侵植物的生长，并可能改变根际微生物群落，这反过来又会增加此类入侵者定植的风险。这种反应可以由植物类型和入侵土壤的特征决定。本研究的目标是升高的CO的效果比较₂ 2个入侵者具有不同程度的侵入，的对根际细菌和真菌社区粉蓝烟草和紫茉莉通过在环境五个不同的半干旱土壤中生长的植物，（410 ppm的) 或升高 (760 ppm) CO ₂. 还评估了入侵者介导的土壤理化、生化和生物学特征的变化。CO ₂供应对地上部干生物量的影响仅对N. glauca显着，在升高的 CO ₂下生长的植物的地上部和根部生物量分别比在环境 CO 下生长的植物高约 53% 和 14% ₂ . 升高的 CO ₂仅促进了根际细菌群落组成的变化，并增强了与N. glauca 中核苷和核苷酸生物合成和 N 循环相关的细菌功能潜力。在细菌指示物种中，鞘氨醇单胞菌属、Stenotrophobacter和Gaiella是在根际更丰富N.青冈下生长的植物升高CO ₂。该研究表明，入侵植物的地上和地下生物量对 CO ₂富集的响应，以及土壤微生物群落的组成和功能，取决于它们的入侵程度。