The rhizosphere effect of plants affects soil organic carbon (SOC) mineralization. It is still unclear for the mechanism by which the rhizosphere effect of dominant plants in secondary broadleaved forest habitats invaded by moso bamboo affects SOC mineralization. Taking broadleaved tree species (Quercus glauca and Cunninghamia lanceolata) and moso bamboo, dominating respectively in uninvaded secondary broadleaved forest and bamboo forest formed after the invasion as test materials, we investigated rhizosphere effect of plants on the SOC mineralization in laboratory incubation experiments. The results showed that carbon mineralization rates of Phyllostachys edulis (PE), Quercus glauca (QG) and Cunninghamia lanceolata (CL) rhizosphere soils were 20%, 26%, and 21% higher than bulk soils, respectively. Carbon mineralization of bulk soils of QG and CL was 22% and 26% higher, while that of rhizosphere soils was 14% and 11% higher than PE, respectively. The contents of water-soluble organic carbon and organic carbon in rhizosphere soils of the three species were significantly higher than those of bulk soil, and the abundance of rhizosphere soil bacteria was higher than that of non-rhizosphere. The contents of microbial biomass carbon, water-soluble organic carbon, and total nitrogen were important factors influencing carbon mineralization in rhizosphere, while water-soluble organic carbon and microbial metabolic quotient were important factors influencing carbon mineralization in non-rhizosphere. On the whole, the rhizosphere effect increased total SOC mineralization, driving by changes in microbial biomass carbon, water-soluble organic carbon, and total nitrogen content. The results could provide a theoretical basis for plant-soil interaction on soil carbon cycling in bamboo invasion habitats.
植物根际效应会显著影响土壤有机碳矿化进程,但目前毛竹入侵次生阔叶林生境优势植物的根际效应对土壤有机碳矿化的影响机制尚不明确。本研究以未被入侵的次生阔叶林优势树种(青冈和杉木)和入侵后形成的毛竹纯林中的毛竹为研究对象,采用室内土壤有机碳矿化培养试验,并结合土壤生物和理化指标,探究根际效应对土壤有机碳矿化过程的影响。结果表明: 毛竹、青冈和杉木根际土壤碳矿化速率均高于非根际土壤,根际比非根际分别高20%、26%和21%。青冈和杉木非根际土壤碳矿化量分别比毛竹高22%和26%;而根际土壤碳矿化量分别比毛竹高14%和11%。3种植物根际土壤水溶性有机碳、有机碳含量显著高于非根际土壤,根际土壤细菌丰度高于非根际。微生物生物量碳、水溶性有机碳和总氮是影响根际土壤碳矿化的重要因素,而水溶性有机碳和微生物代谢熵是影响非根际土壤碳矿化的重要因素。总体上,受微生物生物量碳、水溶性有机碳、总氮含量变化的驱动,根际效应增加了土壤有机碳矿化总量。本研究结果可为入侵生境植物-土壤互作影响土壤碳循环研究提供理论基础。.
Keywords: moso bamboo; rhizosphere effect; secondary broadleaf forest; soil carbon mineralization.