碳氮有效性对亚热带人工林土壤微生物呼吸及其代谢响应的影响OA北大核心CSTPCDMEDLINE

We examined the metabolic response of microbial respiration to glucose addition with the topsoil(0-10 cm)from five plantation types,including Quercus glauca,Castanopsis kawakamii,Pinus massoniana,Phoebe bournei,and Cinnamomum camphora plantations,in the Sanming Forest Ecosystem National Field Observation and Research Station in Fujian Province.The results showed that glucose addition significantly increased microbial res-piration by 82.4％-349.5％,with significant difference among tree species.In the control,microbial respiration significantly correlated with microbial biomass carbon,soil organic carbon,and the fungi/bacteria ratio,indicating that microbial metabolism was regulated by soil organic carbon content and was associated with microbial biomass and community structure in the absence of labile carbon supply.In the glucose addition treatment,microbial respi-ration positively correlated with soil total nitrogen,dissolved organic nitrogen,and mineral nitrogen,indicating that microbial metabolism was mainly constrained by soil nitrogen content and its availability in the presence of adequate labile carbon supply.The metabolic response of microbial respiration,as indicated by the ratio of microbial respira-tion in the glucose addition treatment to that in the control,was primarily affected by soil carbon/nitrogen ratio,with a decrease in the ratio leading to an increase in the microbial metabolic response.Additionally,soil pH played an important role in mediating microbial metabolic response.The effect of the content and availability of soil carbon and nitrogen on microbial respiration depended on whether microbes were carbon-limited.Soil carbon content media-ted microbial respiration when microbes were carbon-limited,whereas soil nitrogen content and availability media-ted microbial respiration after the alleviation of microbial carbon limitation.