Invasive species are considered a serious threat to local biodiversity and ecosystem functioning. Invasive success is often dictated via a plant’s capacity to influence belowground processes. We considered the role of two invasive plants – Solanum elaeagnifolium Cav, a perennial, and Conyza bonariensis L, an annual species – on the rhizosphere soil microbial communities and soil functionality. This study included the cultivation of each of the invasive species and bare soil as a control, in a mesocosm experiment. Rhizosphere soil was collected at three samplings during plant growth. Phospholipid fatty acids and the activities of β-glucosidase, N-acetylglucosaminidase, urease, peroxidase, polyphenol oxidase and acid phosphomonoesterase were analysed. Soil planted with invasive plants exhibited different enzyme activities and microbial biomasses compared with controls. Also, the plant species had soil enzyme profiles that differed from each other, mostly at the vegetative stage, lesser at the maturity stage, with no difference recorded at the middle of the annual cycle. The differences between plant species were significant for microeukaryotes, actinomycetes and the fungi/bacteria and Gram-positive/Gram-negative bacteria ratios but not significant for total microbial biomass and biomasses of Gram-positive and -negative bacteria and fungi in all samplings. The network of interactions among the microbial community and enzymes was affected by plant presence, plant species as well as plant growth stage. This study suggests that life-cycle stage is important in relation to invasive species influence on belowground processes.

中文翻译：

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植物入侵者对根际微生物属性的影响取决于植物身份和生长阶段

入侵物种被认为是对当地生物多样性和生态系统功能的严重威胁。侵入性成功通常取决于植物影响地下过程的能力。我们考虑了两种入侵植物——多年生植物 Solanum elaeagnifolium Cav 和一年生植物 Conyza bonariensis L——对根际土壤微生物群落和土壤功能的作用。这项研究包括在中观实验中种植每种入侵物种和裸露土壤作为对照。在植物生长过程中，在三个采样点收集根际土壤。分析了磷脂脂肪酸和β-葡萄糖苷酶、N-乙酰氨基葡萄糖苷酶、脲酶、过氧化物酶、多酚氧化酶和酸性磷酸单酯酶的活性。与对照相比，种植入侵植物的土壤表现出不同的酶活性和微生物生物量。此外，植物物种的土壤酶谱彼此不同，主要在营养阶段，在成熟阶段较少，在年循环中期没有记录差异。植物物种之间的差异对于微真核生物、放线菌和真菌/细菌以及革兰氏阳性/革兰氏阴性细菌比率而言是显着的，但对于所有样品中的总微生物生物量以及革兰氏阳性和阴性细菌和真菌的生物量而言不显着。微生物群落和酶之间的相互作用网络受植物存在、植物种类以及植物生长阶段的影响。