Impacts of 3 years of elevated atmospheric CO2 on rhizosphere carbon flow and microbial community dynamics
Impacts of 3 years of elevated atmospheric CO2 on rhizosphere carbon flow and microbial community dynamics
复制标题
DOI：
10.1111/gcb.12045
复制
发表时间：
2013-02-01
影响因子：
11.6
通讯作者：
van Veen, Johannes A.
中科院分区：
文献类型：
--
作者：
Drigo, Barbara;Kowalchuk, George A.;van Veen, Johannes A.
陆地生态系统的碳（C）吸收是部分减缓人为CO2排放的一个重要选择。短期大气CO2暴露已被证明会造成碳流动路线和活性土壤微生物群落多样性的重大变化。由于土壤微生物对有机碳流量增加的潜在适应，CO2的长期增加被假设具有微妙的影响。在这里，我们研究了长期大气CO2浓度升高暴露对根际微生物C流和微生物群落的影响。苔草arenaria（非菌根植物物种）和紫羊茅（菌根植物物种）生长在定义的大气条件下不同的CO2浓度（350和700 ppm）3年。在此期间，C流反复评估（6个月后，1，2，3年）的C-13脉冲追踪实验，并通过根际细菌，一般真菌，丛枝菌根真菌（AMF）社区的标签进行跟踪。脂肪酸生物标志物分析和RNA稳定同位素探测（RNA-SIP），结合实时PCR和PCR-DGGE，用于检查微生物群落动态和丰度。在整个实验中，CO2浓度升高的影响是高度依赖于植物的，菌根植物对细菌和真菌群落产生更大的影响。生物标志物数据证实，根际沉积的C首先被AMF处理，随后转移到根际土壤中的细菌和真菌群落。在3年的过程中，CO2浓度升高导致C-13富集保留在AMF中的持续增加和C转移到细菌群落的延迟增加。这些结果表明，不仅大气CO2浓度升高的条件下引起根际碳流和动态的变化，但也继续发展，在多个季节，从而影响陆地生态系统的碳利用过程。
Carbon (C) uptake by terrestrial ecosystems represents an important option for partially mitigating anthropogenic CO2 emissions. Short-term atmospheric elevated CO2 exposure has been shown to create major shifts in C flow routes and diversity of the active soil-borne microbial community. Long-term increases in CO2 have been hypothesized to have subtle effects due to the potential adaptation of soil microorganism to the increased flow of organic C. Here, we studied the effects of prolonged elevated atmospheric CO2 exposure on microbial C flow and microbial communities in the rhizosphere. Carex arenaria (a nonmycorrhizal plant species) and Festuca rubra (a mycorrhizal plant species) were grown at defined atmospheric conditions differing in CO2 concentration (350 and 700 ppm) for 3 years. During this period, C flow was assessed repeatedly (after 6 months, 1, 2, and 3 years) by C-13 pulse-chase experiments, and label was tracked through the rhizosphere bacterial, general fungal, and arbuscular mycorrhizal fungal (AMF) communities. Fatty acid biomarker analyses and RNA-stable isotope probing (RNA-SIP), in combination with real-time PCR and PCR-DGGE, were used to examine microbial community dynamics and abundance. Throughout the experiment the influence of elevated CO2 was highly plant dependent, with the mycorrhizal plant exerting a greater influence on both bacterial and fungal communities. Biomarker data confirmed that rhizodeposited C was first processed by AMF and subsequently transferred to bacterial and fungal communities in the rhizosphere soil. Over the course of 3 years, elevated CO2 caused a continuous increase in the C-13 enrichment retained in AMF and an increasing delay in the transfer of C to the bacterial community. These results show that, not only do elevated atmospheric CO2 conditions induce changes in rhizosphere C flow and dynamics but also continue to develop over multiple seasons, thereby affecting terrestrial ecosystems C utilization processes.