臭氧浓度升高对土壤-冬小麦系统CO_2排放的影响

Effects of Elevated Ozone Concentration on CO_2 Emission from Soil-Winter Wheat System

通过田间试验,采用静态箱-气相色谱法测定CO2排放通量,研究臭氧(O3)浓度升高对土壤-冬小麦系统CO2排放的影响.结果表明,O3浓度升高对CO2排放的季节变化模式无明显影响.在返青期和拔节孕穗期,O3浓度升高显著降低了土壤-冬小麦系统的CO2排放通量;在抽穗成熟期,O3浓度100 nL.L-1处理对CO2排放通量没有显著影响,但150 nL.L-1 O3浓度处理显著降低了CO2排放通量.对照、100 nL.L-1和150 nL.L-1 O3浓度处理的土壤-冬小麦系统呼吸速率与气温均存在极其显著的指数关系(p<0.01),拟合方程的决定系数R2分别为0.139、0.513和0.211,温度敏感性系数Q10值分别为1.13、1.58和1.21.本研究表明O3浓度升高可能会导致农田CO2排放量降低.

To investigate the impact of elevated ozone （O3 ） on CO2 emission from soil-winter wheat system, outdoor experiments with simulating elevated O3 concentration were conducted, and static dark chamber-gas chromatograph method was used to measure CO2 emission fluxes. Results indicated that the elevated O3 did not change the seasonal pattern of CO2 emissions from soil-winter wheat system, but significantly decreased CO2 emission fluxes during turning-green stage and elongation-pregnant stage. From heading to maturity, CO2 emission fluxes were not found to be significant difference under 100 nL.L^-1 O3 treatment compared with the control, while 150 nL.L^-1 O3 treatment significantly declined CO2 emission fluxes. Significant relationships were found between respiration rate and air temperature under the control, 100 nL.L^-1 and 150 nL. L^-1 O3 treatment, and the fitting equation determined coefficients R2 were 0. 139, 0. 513 and 0. 211, respectively. In addition, the Q l0 （temperature sensitivity coefficients） for soil-winter wheat system＇ s respiration were 1. 13, 1.58and 1.21, respectively. The results of this study suggested that elevated O3 could reduce CO2 emissions from agroecosystem.