二氧化碳浓度升高与氮沉降对三江平原小叶章群落生物量累积及其分配格局的影响

通过开顶式气室控制大气CO2浓度（370、550及700 μmol/mol），施加不同量NH4NO3设置氮素梯度0，4，8 g/(m2?a)]，研究了大气CO2浓度升高和氮素增加对三江平原湿地小叶章群落生物量及生物量分配的影响。结果表明，在不同氮素水平下，小叶章天然群落地上生物量随CO2浓度的增加而下降，地下生物量却随CO2浓度的增加表现为先增加而后下降；总生物量随CO2浓度的增加而下降；不同处理下小叶章群落根、茎、叶生物量比重变化趋势不同。CO2浓度及N素处理对根生物量影响显著，对小叶章群落生物量格局影响差异不显著。

Effects of Elevated CO2 Concentration and N Deposition on Plant Biomass Accumulation and Allocation in the Communities of Deyeuxia angustifolia in Sanjiang Plain

The CO_2 concentration （370,550,700 μmol/mol） was controlled with open-top chambers,and different contents of NH_4NO_3 were supplied to control nitrogen levels 0,4,8 g/（m~2·a）].This paper studied the effects of elevated atmospheric CO_2 concentration and nitrogen deposition on biomass accumulation and allocation in Deyeuxia angustifolia communities in Sanjiang Plain.The results showed that the aboveground biomass of Deyeuxia angustifolia communities decreased with atmospheric CO_2 concentration increasing,under different nitrogen supply levels.While belowground increased began and decreased afterwards.The total biomass of Deyeuxia angustifolia communities decreased with atmospheric CO_2 concentration increasing,under different nitrogen supply levels.The changed trends of the biomass in roots,stems and leaves of Deyeuxia angustifolia communities in varied treatments were different.The elevated atmospheric CO_2 concentration and nitrogen deposition could affect the roots biomass significantly,but could not affect biomass allocation of Deyeuxia angustifolia communities significantly.