Liu Yu, Hu Xiao-Fei, Chen Fu-Sheng, Yuan Ping-Cheng
College of Life Sciences and Food Engineering, Nanchang University, Nanchang 330031, China.
Ying Yong Sheng Tai Xue Bao. 2013 Jun;24(6):1501-8.
Rhizospheric and non-rhizospheric soils and the absorption, transition, and storage roots were sampled from the mid-subtropical Pinus massoniana and Castanopsis sclerophylla forests to study the CO2 fluxes from soil mineralization and root decomposition in the forests. The samples were incubated in closed jars at 15 degrees C, 25 degrees C, 35 degrees C, and 45 degrees C, respectively, and alkali absorption method was applied to measure the CO2 fluxes during 53 days incubation. For the two forests, the rhizospheric effect (ratio of rhizospheric to non-rhizospheric soil) on the CO2 flux from soil mineralization across all incubation temperature ranged from 1.12 to 3.09, with a decreasing trend along incubation days. There was no significant difference in the CO2 flux from soil mineralization between the two forests at 15 degrees C, but the CO2 flux was significantly higher in P. massoniana forest than in C. sclerophylla forest at 25 degrees C and 35 degrees C, and in an opposite pattern at 45 degrees C. At all incubation temperature, the CO2 release from the absorption root decomposition was higher than that from the transition and storage roots decomposition, and was smaller in P. massoniana than in C. sclerophylla forest for all the root functional types. The Q10 values of the CO2 fluxes from the two forests were higher for soils (1.21-1.83) than for roots (0.96-1.36). No significant differences were observed in the Q10 values of the CO2 flux from soil mineralization between the two forests, but the Q10 value of the CO2 flux from root decomposition was significantly higher in P. massoniana than in C. sclerophylla forest. It was suggested that the increment of CO2 flux from soil mineralization under global warming was far higher than that from root decomposition, and for P. massoniana than for C. sclerophylla forest. In subtropics of China, the adaptability of zonal climax community to global warming would be stronger than that of pioneer community.
从亚热带中部的马尾松林和苦槠林中采集根际和非根际土壤以及吸收根、过渡根和贮藏根，以研究森林土壤矿化和根系分解产生的二氧化碳通量。将样品分别在15℃、25℃、35℃和45℃的密闭广口瓶中培养，并采用碱吸收法测定53天培养期间的二氧化碳通量。对于这两种森林，在所有培养温度下，根际效应（根际土壤与非根际土壤的比值）对土壤矿化产生的二氧化碳通量的影响范围为1.12至3.09，且随培养天数呈下降趋势。在15℃时，两种森林土壤矿化产生的二氧化碳通量无显著差异，但在25℃和35℃时，马尾松林的二氧化碳通量显著高于苦槠林，而在45℃时则相反。在所有培养温度下，吸收根分解产生的二氧化碳释放量高于过渡根和贮藏根分解产生的二氧化碳释放量，并且对于所有根系功能类型，马尾松林中的二氧化碳释放量均小于苦槠林。两种森林土壤二氧化碳通量的Q10值（1.21 - 1.83）高于根系（0.96 - 1.36）。两种森林土壤矿化产生的二氧化碳通量的Q10值未观察到显著差异，但马尾松林根系分解产生的二氧化碳通量的Q10值显著高于苦槠林。研究表明，全球变暖下土壤矿化产生的二氧化碳通量的增加远高于根系分解产生的二氧化碳通量的增加，且马尾松林高于苦槠林。在中国亚热带地区，地带性顶极群落对全球变暖的适应性将强于先锋群落。
