中文摘要：

为了探究大气CO2升高对沉水植物光合生理的影响，利用便携式植物效率分析仪（Handy PEA），在无损的情况下测定不同CO2浓度处理下的苦草（Vallisneria natarts）叶绿素荧光诱导曲线，并采用JIP-test分析方法分析数据，研究CO2浓度对苦草叶片叶绿素荧光特性的影响。结果表明在实验进行60d后，与对照相比，高CO2浓度处理下的苦草叶片PS Ⅱ反应中心受体侧荧光参数Kj、Mo显著升高，Sm、ψo、ψEo显著降低，叶片电子传递能力减弱；K相相对可变荧光阢显著提高，PSⅡ反应中心供体侧放氧复合体OEC受到伤害；ABS／RC、DI0／RC、TR0／RC、DI0／CS0显著升高，ET0／RC、RE0／RC、ETo／CSo、REo／CSo显著降低，苦草叶片用于热耗散的能量显著增加，导致用于电子传递及传递到电子链末端的能量显著减少；性能参数Fv／Fm、PIabs显著降低，苦草叶片PSⅡ潜在活性和光合作用原初反应过程受到抑制。以上结果表明，在长期高CO2浓度处理下，苦草叶片光合机构功能受到抑制，PSⅡ反应中心活性降低，光合功能下调，发生光适应现象。

英文摘要：

To explore the effects of elevated atmospheric CO2 on photosynthetic physiology of submerged plant, we studied the effects of high concentrations of CO2 on chlorophyll fluorescence characteristics of Vallisneria natans by measuring the rapid fluorescence induction kinetics curves （OJIP） of the leaves with Plant Efficiency Analyzer and analyzing with JIP-test. The Vj, Mo of V. natans were significantly increased and Sm、ψo and ψEo were significantly reduced after 60 days, and the electron transfer diminished capacity of V. natans was decreased compared with the control; the donor side of PS Ⅱ reaction center was hurt because the Wk was increased ; the specific activity parameters ABS/RC, DIo/RC, TRo/RC, DIo/CSo were significantly increased, ETo/RC, REo/RC, ETo/CSo, REo/CSo significantly decreased, and the energy for heat dissipation significant increased lead to the energy of electron transfer and electron transfer chain end were significantly decreased. Compared with the control, the performance parameters Fv/Fm and Plabs were also decreased. Therefore, the long-term high concentrations of CO2 suppressed photosynthetic apparatus state, decreased PSⅡ reaction center activity and down regulated photosynthetic function of V. natans, and the V. natans appeared light acclimation.