马占相思人工林净二氧化碳交换和碳同位素通量  

Net CO2 exchange and carbon isotope flux in Acacia mangium plantation

作　　者：邹绿柳[1,2] 孙谷畴[1] 赵平[1] 蔡锡安[1] 曾小平[1] 王权[3] 

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,北京100049 [3]静冈大学农学部,日本静冈422-8529

出　　处：《应用生态学报》2009年第11期2594-2602,共9页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(30428022、30770328、30871998);中国科学院知识创新工程重要方向性项目(KSCX2-SW-133);广东省自然科学基金项目(07006917)资助.

摘　　要：应用稳定碳同位素技术,对马占相思人工林冠层受光和遮荫叶片的碳同化率（Anet）和叶面积指数（L）进行加权,将叶片水平的13C甄别率（Δi）扩展至冠层光合甄别率（Δcanopy）,测定光合固定和呼吸释放的碳同位素通量及其净交换通量.结果表明：Δcanopy的日变化明显,日出前和中午出现较低值（18.47‰和19.87‰）,而日落前达到最大（21.21‰）;秋季末期（11月）至翌年夏季,Δcanopy逐步升高,年平均为（20.37±0.29）‰.不同季节自养呼吸（日间叶片呼吸除外）和异养呼吸释放CO2的碳同位素比率（δ13C）平均值分别为（-28.70±0.75）‰和（-26.75±1.3）‰,春季林冠夜间呼吸CO2的1δ3C最低（-30.14‰）,秋季末期最高（-28.01‰）.马占相思林与大气的CO2碳同位素通量在春季和夏季中午时峰值分别为178.5和217μmol.m-2.s-1.‰,日均值分别为638.4和873.2μmol.m-2.s-1.‰.冠层叶片吸收CO2的碳同位素通量较呼吸释出CO2的碳同位素通量高1.6~2.5倍,表明马占相思林日间吸收大量CO2,降低空气CO2浓度,具有改善环境的良好生态服务功能.By using stable carbon isotope technique, the leaf-level 13C discrimination was integrated to canopy-scale photosynthetic discrimination （△camopy ） through weighted the net CO2 assimilation （△net,） of sunlit and shaded leaves and the stand leaf area index （L） in an A. mangium plantation, and the carbon isotope fluxes from photosynthesis and respiration as well as their net exchange flux were obtained. There was an obvious diurnal variation in △canopy, being lower at dawn and at noon time （18.47‰ and 19.87‰, respectively） and the highest （21.21‰） at dusk. From the end of November to next May, the △canopy had an increasing trend, with an annual average of （20. 37 ± 0. 29）‰. The carbon isotope ratios of CO2 from autotrophic respiration （ excluding daytime foliar respiration） and heterotrophic respiration were respectively （ - 28.70 ±0. 75 ） ‰ and （ - 26. 75± 1.3）‰ in average. The δ13C of nighttime ecosystem-respired CO2 in May was the lowest （-30. 14‰）, while that in November was the highest （-28.01‰）. The carbon isotope flux of CO= between A. mangium forest and atmosphere showed a midday peak of 178.5 and 217 μmol.m-2.s-1.‰ in May and July, with the daily average of 638.4 and 873.2μmol.m-2.s-1.‰, respectively. The carbon isotope flux of CO2 absorbed by canopy leaves was 1.6-2. 5 times higher than that of CO2 emitted from respiration, suggesting that a large sum of CO2 was absorbed by A. mangium, which decreased the atmospheric CO2 concentration and improved the environment.

关 键 词：马占相思林 冠层光合甄别率 碳同位素通量 

分 类 号：S718.5[农业科学—林学]