中文摘要：

研究了三江平原小叶章和毛果苔草两种地表覆被下的贴地气层CO2浓度分布特征．结果表明，小叶章和毛果苔草两种地表覆被下贴地气层CO2平均浓度要明显高于全球大气中CO2平均浓度及向海湿地大气中CO2平均浓度，毛果苔草贴地气层CO2平均浓度（389．56μmol／mol）低于小叶章草甸（400．04μmol／mol）．在生长初期，毛果苔草和小叶章草甸日变化曲线均是单峰型；成熟期，毛果苔草为单峰型曲线，而小叶章草甸0m、0．5m高度为明显的双峰型曲线，峰值分别出现在12点左右和18点左右．一个完整的生长季中，毛果苔草和小叶章的贴地层CO2浓度最高峰均出现在植物生长之前；但是两种覆被下的贴地气层CO2最大值却出现在不同的高度，毛果苔草最大值在2m处，小叶章草甸出现在0m处．

英文摘要：

In the paper, the distribution of ambient CO2 concentration of two different land-covers, Deyeuxia angustifolia and Carex lasiocapa, in the Sanjiang Plain was studied. The results showed that the average ambient CO2 concentration of Deyeuxia angustifolia and Carex lasiocapa was 400.04μmol/mol and 389.56μmol/mol, respectively, obviously higher than that of Xianghai wetland. At the beginning of growth, daily change curves both showed a single-peak characteristic of Deyeuxia angustifolia and Carex lasiocapa. In contrast, in the maturity season, Carex lasiocapa showed single-peak characteristic and Deyeuxia angustifolia showed double-peak characteristic. In the whole season, the highest ambient CO2 concentrations of Deyeuxia angustifolia and Carex lasiocapa were both observed at the time before growth. But the highest ambient CO2 concentration of Carex lasiocapa was observed at 2m and that of Deyeuxia angustifolia was 0m.