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Chromolaena odorata is a noxious alien invasive weed species with an enormous impact on the terrestrial ecosystem. The allelopathic potentials of this weed have had little attention, leading to changes in soil properties and microbial communities. This study investigates the impacts of Chromolaena odorata invasion gradients on rhizospheric soil chemical properties and microbial response in the Mount Cameroon Region. Forty-eight soil samples at four different degrees of invasion (uninvaded, low degree invasion, moderate degree invasion and high degree invasion) based on species coverage within subplots in four study areas were collected and rhizospheric soil chemical properties, microbial load, phosphatases activities and secondary metabolites were evaluated. At medium-degree invasion, rhizospheric soil concentrations of P, K and Fe increased with arbuscular mycorrhizal fungi (AMF) colonization and phosphatases enzyme activities. Soil C, N and organic matter were significantly increased at high-degree invasion, supporting the use of the plant as a fallow crop. Acid phosphatase activity ranged from 0.69 to 0.90 mmol h-1 kg-1 and was significantly different at different degrees of invasion. AMF colonization ranged from 23.33 to 50.00%, with a strong positive correlation between AMF colonization and phosphatase activity. Soil bacterial load was high (46 × 105 CFU/g– 67 × 105 CFU/g), with mostly Staphylococcus having health concerns about its spread. The invasion situation had no significant effect on soil bacterial load, but high-degree invasion significantly increased fungal load. Low-degree invaded soils had high saponin (24.55±0.00 mg/g), flavonoid (47.7 mg/g) and tannin (28.68 mg/g) concentrations. The investigation reveals that Chromolaena odorata invasion altered rhizospheric soil properties and microbial communities significantly, thereby influencing ecosystem dynamics and soil nutrient availability. However, further studies elucidating kinds of secondary metabolites, identifying microbial communities, and monitoring soil changes influenced by C. odorata are essential for effective ecosystem management.

紫茎泽兰（Chromolaena odorata）是一种恶性外来入侵杂草，对陆地生态系统造成极大危害。目前该杂草的化感潜力尚未得到足够关注，但其化感作用可改变土壤性质与微生物群落结构。本研究以喀麦隆山地为研究区域，探讨紫茎泽兰入侵梯度对根际土壤化学性质及微生物响应的影响。研究在4个样区的样方内，基于物种盖度设置4个入侵梯度（未入侵、轻度入侵、中度入侵、重度入侵），共采集48份土壤样品，并对根际土壤化学性质、微生物载荷、磷酸酶活性及次生代谢产物进行了测定分析。在中度入侵梯度下，根际土壤的磷（P）、钾（K）和铁（Fe）含量随丛枝菌根真菌（arbuscular mycorrhizal fungi, AMF）定殖率及磷酸酶活性升高而增加；重度入侵梯度下，土壤碳（C）、氮（N）及有机质含量显著提升，为该植物作为休耕作物的应用提供了支撑。酸性磷酸酶活性范围为0.69~0.90 mmol·h⁻¹·kg⁻¹，且在不同入侵梯度下存在显著差异。丛枝菌根真菌定殖率介于23.33%~50.00%之间，其定殖率与磷酸酶活性呈显著正相关。土壤细菌载荷处于较高水平（46×10⁵ CFU/g ~ 67×10⁵ CFU/g），其中以葡萄球菌属（Staphylococcus）为主，其扩散存在健康风险。入侵程度对土壤细菌载荷无显著影响，但重度入侵显著提升了土壤真菌载荷。轻度入侵土壤中的皂苷（saponin）、黄酮类化合物（flavonoid）及单宁（tannin）含量较高，分别为24.55±0.00 mg/g、47.7 mg/g及28.68 mg/g。本研究结果表明，紫茎泽兰入侵可显著改变根际土壤性质与微生物群落结构，进而影响生态系统动态及土壤养分有效性。然而，为实现有效的生态系统管理，仍需开展进一步研究以明确紫茎泽兰影响下的次生代谢物种类、鉴定其相关微生物群落，并监测土壤变化情况。