Nie San-An, Zhou Ping, Ge Ti-Da, Tong Cheng-Li, Xiao He-Ai, Wu Jin-Shui, Zhang Yang-Zhu
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
Huan Jing Ke Xue. 2012 Apr;33(4):1346-51.
The microcosm experiment was carried out to quantify the input and distribution of photo-assimilated C into soil C pools by using a 14C continuous labeling technique. Destructive samplings of rice (Oryza sativa) were conducted after labeling for 80 days. The allocation of 14C-labeled photosynthates in plants and soil C pools such as dissolved organic C (DOC) and microbial biomass C (MBC) in rice-planted soil were examined over the 14C labeling span. The amounts of rice shoot and root biomass C was ranged from 1.86 to 5.60 g x pot(-1), 0.46 to 0.78 g x pot(-1) in different tested paddy soils after labeling for 80 days, respectively. The amount of 14C in the soil organic C (14C-SOC) was also dependent on the soils, ranged from 114.3 to 348.2 mg x kg(-1), accounting for 5.09% to 6.62% of the rice biomass 14C, respectively. The amounts of 14C in the dissolved organic C (14C-DOC) and in the microbial biomass C(14C-MBC), as proportions of 14C-SOC, were 2.21%-3.54% and 9.72% -17.2%, respectively. The 14C-DOC, 14C-MBC, and 14C-SOC as proportions of total DOC, MBC, and SOC, respectively, were 6.72% -14.64%, 1.70% -7.67%, and 0.73% -1.99%, respectively. Moreover, the distribution and transformation of root-derived C had a greater influence on the dynamics of DOC and MBC than on the dynamics of SOC. Further studies are required to ascertain the functional significance of soil microorganisms (such as C-sequestering bacteria and photosynthetic bacteria) in the paddy system.
采用¹⁴C连续标记技术进行微观实验，以量化光同化碳输入土壤碳库及其在土壤碳库中的分配情况。标记80天后对水稻（Oryza sativa）进行破坏性采样。在¹⁴C标记期内，研究了¹⁴C标记光合产物在植物以及水稻种植土壤中的溶解有机碳（DOC）和微生物生物量碳（MBC）等土壤碳库中的分配情况。标记80天后，不同供试水稻土中地上部和根系生物量碳含量分别为1.86至5.60 g·盆⁻¹、0.46至0.78 g·盆⁻¹。土壤有机碳中¹⁴C含量（¹⁴C-SOC）也因土壤而异，范围为114.3至348.2 mg·kg⁻¹，分别占水稻生物量¹⁴C的5.09%至6.62%。溶解有机碳中¹⁴C含量（¹⁴C-DOC）和微生物生物量碳中¹⁴C含量（¹⁴C-MBC）分别占¹⁴C-SOC的2.21% - 3.54%和9.72% - 17.2%。¹⁴C-DOC、¹⁴C-MBC和¹⁴C-SOC分别占总DOC、MBC和SOC的比例为6.72% - 14.64%、1.70% - 7.67%和0.73% - 1.99%。此外，根系来源碳的分配和转化对DOC和MBC动态变化的影响大于对SOC动态变化的影响。需要进一步研究以确定稻田系统中土壤微生物（如固碳细菌和光合细菌）的功能意义。
