[Temperature sensitivity of CO2 fluxes from rhizosphere soil mineralization and root decomposition in Pinus massoniana and Castanopsis sclerophylla forests].
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.
College of Life Sciences and Food Engineering, Nanchang University, Nanchang 330031, China. liuyuncdx@163.com
Yu
Y
Liu
Xiao-Fei
XF
Hu
Fu-Sheng
FS
Chen
Ping-Cheng
PC
Yuan
D002245:Carbon Dioxide / Q000378:metabolism*; D002681:China; D029962:Fagaceae / Q000378:metabolism*; D065928:Forests; D008903:Minerals / Q000737:chemistry; D028223:Pinus / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism; D058441:Rhizosphere; D012987:Soil / Q000737:chemistry*; D013696:Temperature
D008903:Minerals; D012987:Soil; D002245:Carbon Dioxide