Shi Ran, Chen Xiao-Juan, Wu Xiao-Hong, Jian Yan, Yuan Hong-Zhao, Ge Ti-Da, Sui Fang-Gong, Tong Cheng-Li, Wu Jin-Shui
School of Resource and Environment, Qingdao Agricultural University, Qingdao 266109, China.
Huan Jing Ke Xue. 2013 Jul;34(7):2809-14.
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 x 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 x kg(-1), 19.50 to 49.16 mg x 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.
土壤自养微生物数量众多且分布广泛。然而，微生物自养过程在土壤碳固存中的作用及其机制仍知之甚少。在此，我们使用在封闭的、持续标记14C-CO2的大气中培养110天的土壤来测量掺入微生物生物量中的标记碳量。在14C标记期间，还研究了14C标记的同化碳在可变土壤碳库（如溶解有机碳（DOC）和微生物生物量碳（MBC））中的分配情况。结果表明，在水稻土中测量到大量的14C-SOC，范围为69.06 - 133.81 mg x kg(-1)，占土壤有机碳（SOC）总量的0.58%至0.92%。溶解有机碳（14C-DOC）和微生物生物量碳（14C-MBC）中的14C量取决于土壤，分别为2.54至8.10 mg x kg(-1)、19.50至49.16 mg x kg(-1)。14C-SOC和14C-MBC浓度之间存在显著的正线性关系（R2 = 0.957**，P < 0.01）。14C-DOC和14C-MBC占总DOC、MBC的比例分别为5.65% - 24.91%和4.23% - 20.02%。此外，微生物同化衍生碳的分布和转化对DOC和MBC动态的影响大于对SOC动态的影响。这些数据为微生物在固定大气CO2中的重要性以及微生物自养对陆地碳循环的潜在重大贡献提供了新的见解。
