土壤自养微生物同化碳向土壤有机碳库输入的定量研究:^(14)C连续标记法  

Quantifying Soil Autotrophic Microbes-Assimilated Carbon Input into Soil Organic Carbon Pools Following Continuous ^(14)C Labeling

作　　者：史然[1,2] 陈晓娟[2] 吴小红[2] 简燕[2] 袁红朝[2] 葛体达[2] 隋方功[1] 童成立[2] 吴金水[2] 

机构地区：[1]青岛农业大学资源与环境学院,青岛266109 [2]中国科学院亚热带农业生态研究所农业生态系统过程重点实验室,长沙410125

出　　处：《环境科学》2013年第7期2809-2814,共6页Environmental Science

基　　金：国家自然科学基金项目(41271279;41090283);湖南省自然科学基金项目(11JJ4030);中国科学院青年创新促进会会员项目(2012-2015);中国科学院亚热带农业生态过程重点实验室开放基金项目(2010-2012)

摘　　要：自养微生物在土壤中广泛存在,但其CO2同化能力及其向土壤碳库的输入机制尚不明确.应用14C连续标记示踪技术,选取亚热带区4种典型稻田土壤在密闭系统模拟培养,探讨了土壤自养微生物同化碳向土壤碳库的输入过程和机制及其对土壤碳库活性组分的影响.结果表明,土壤微生物具有客观的CO2同化能力.标记培养110 d后,供试土壤的14C-SOC含量范围为69.06～133.81 mg.kg-1,而14C-DOC、14C-MBC含量范围为2.54～8.10 mg.kg-1、19.50～49.16 mg.kg-1.土壤自养微生物同化碳(14C-SOC)与其微生物截留碳(14C-MBC)呈极显著的正相关关系.土壤可溶解性有机碳(DOC)、微生物量碳(MBC)和SOC的更新率分别为5.65%～24.91%、4.23%～20.02%和0.58%～0.92%.而且,土壤自养微生物同化碳的输入对土壤活性碳组分的DOC、MBC含量变化影响较大,而对SOC影响较小.对微生物在土壤碳循环过程的基本功能的认识在本研究中得以丰富和加深.Soil autotrophic microbe has been found numerous and widespread. However, roles of microbial autotrophic processes and the mechanisms of that in the soil carbon sequestration remain poorly understood. Here, we used soils incubated for 110 days in a closed, continuously labeled 14C-CO2 atmosphere to measure the amount of labeled C incorporated into the microbial biomass. The allocation of 14C-labeled assimilated carbon in variable soil C pools such as dissolved organic C （DOC） and microbial biomass C （MBC） were also examined over the 14C labeling span. The results showed that significant amounts of 14C-SOC were measured in paddy soils, which ranged from 69.06-133.81 mg·kg-1, accounting for 0.58% to 0.92% of the total soil organic carbon （SOC）. The amounts of 14C in the dissolved organic C （14C-DOC） and in the microbial biomass C （14C-MBC） were dependent on the soils, ranged from 2.54 to 8.10 mg·kg-1, 19.50 to 49.16 mg·kg-1, respectively. There was a significantly positive linear relationship between concentrations of 14C-SOC and 14C-MBC （R2=0.957＊＊, P〈0.01）. The 14C-DOC and 14C-MBC as proportions of total DOC, MBC, were 5.65%-24.91% and 4.23%-20.02%, respectively. Moreover, the distribution and transformation of microbes-assimilated-derived C had a greater influence on the dynamics of DOC and MBC than that on the dynamics of SOC. These data provide new insights into the importance of microorganisms in the fixation of atmospheric CO2 and of the potentially significant contributions made by microbial autotrophy to terrestrial C cycling.

关 键 词：土壤自养微生物 CO2同化 同化碳 14C连续标记 稻田土壤 

分 类 号：X144[环境科学与工程—环境科学]