植物-土壤-微生物间碳流对大气CO2浓度升高的响应
Carbon flow in the plant-soil-microbe continuum in response to atmospheric elevated CO2
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摘要: 大气二氧化碳(CO2)浓度升高促进很多植物的光合同化能力,同时增加光合同化碳向土壤中的释放,即增加根系脱落物。在根际范围内,根系脱落物为土壤微生物提供养分和能量来源,根沉积物量和质的改变必然影响到土壤微生物的活性以及群落结构和功能。由于土壤微生物在影响土壤碳循环方面的关键作用,大气CO2浓度升高条件下根际微生物如何参与植物光合碳转化将很大程度上决定未来气候变化条件下土壤碳库的稳定性。本文综述了植物光合碳同化、土壤碳循环以及土壤微生物活性与群落结构对大气CO2浓度升高的响应,从植物-土壤-微生物系统中碳流角度分析高CO2浓度对土壤碳转化的影响机制,并对未来的研究方向进行了展望,提出高CO2浓度条件下同位素标记结合宏基因组技术解析根际碳转化机制将成为农田生态系统领域的研究热点。Abstract: Elevated atmospheric CO2 concentration likely increases the capability of photosynthesis in many plant species, and the secretion of photosynthetically-fixed carbon (C) into the rhizosphere, i.e.rhizodeposits.The changes in quantity and quality of rhizodeposits may fundamentally influence soil microbial activity and community composition, because rhizodeposits are important nutrient and energy resources to microorganisms in the rhizosphere.As microorganisms greatly influence soil C cycling, how soil microorganisms metabolize the plant-derived C will be essential to the soil C stability in climate change.This review summarized and discussed the effects of elevated CO2 (eCO2) on plant-C accumulation, C cycling in soil and microbial activity and community structure.The investigation on the C flow in the plant-soil-microbe continuum in response to eCO2 would be the key to the mechanism of fresh C turnover under such environment.Regarding research perspectives in the future, isotope labelling technologies combined with metagenomic sequencing will help us to gain insight of mechanisms of plant-C turnover in the rhizosphere.