荷木树干CO_2释放通量与木质部液流和CO_2浓度的关系  

Schima superba stem CO_2 efflux and its relations to xylem sap flux density a nd xylem CO_2 concentration.

作　　者：朱丽薇[1,2] 赵平[1] 蔡锡安[1] 曾小平[1] 邹绿柳[1,2] 

机构地区：[1]中国科学院华南植物园,广州510650 [2]中国科学院研究生院,北京100039

出　　处：《生态学杂志》2009年第11期2227-2232,共6页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(30770328;30871998);广东省自然科学基金资助项目(07006917)

摘　　要：采用红外气体分析仪,于2008年10月17—19日连续3个昼夜原位监测了荷木的树干CO2释放通量、树干温度、木质部液流密度和CO2浓度。结果表明:树干CO2释放通量(EA)日变化呈S形曲线,不同径级间差异显著。EA与树干温度呈显著幂函数关系(0.24<R2<0.78),晚上的温度系数(b)、回归系数(R2)高于白天,Q10值在2.01～2.79。EA与木质部CO2浓度显著相关,三次曲线拟合度最好,R2达到0.48。在排除树干温度影响的条件下,EA与液流密度显著负相关(r=-0.462)。仅用温度估算树干CO2释放通量必然产生误差,应考虑液流对树干CO2释放通量的影响。By using a Li-820 infra-red CO2 gas analyzer, an in situ measurement of Schima superba stem CO2 efflux was conducted for three consecutive days from 17 to 19 October 2008. In the meantime, the stem temperature, xylem sap efflux density, and xylem CO2 concentration were measured. The stem CO2 efflux had a diurnal variation of ＂S＂ pattern, and differed significantly with stem diameter. There was a significant exponential relationship between stem CO2 efflux and stem temperature （0. 24 〈 R^2 〈 0. 78 ）. The temperature coefficient （b） and regression coefficient （R2） were higher at nighttime than at daytime, and the Q10 value ranged from 2. 01 to 2.79. The stem CO2 efflux correlated significantly with the xylem COS concentration, and the best regression curve was cubic （R^2=0. 48 ）. Excluding the effects of stem temperature, the stem CO2 efflux showed a significant negative correlation ＇with xylem sap flux density （r = -0. 462）. Therefore, only using simple temperature function to estimate stem CO2 efflux Would yield a significant error, and xylem sap flux should be taken into consideration in the stem COs efflux estimation.

关 键 词：树干CO2释放通量 树干温度 液流密度 木质部CO2浓度 Q10 荷木 

分 类 号：Q945[生物学—植物学]