中文摘要：

用便携式调制叶绿素荧光仪和光合仪研究了强光下不同供氮水平（12、4和0．4mmol·L^-1）和不同CO2浓度下（700和390μl·L^-1）丰香草莓叶片的荧光参数及净光合速率的变化．结果表明，CO2和氮素对草莓叶片光抑制有明显的互作效应．在富CO2下，12mmol·L^-1供氮水平的草莓叶片净光合速率升高了62．7％，4和0．4mmol·L^-1供氮水平则分别降低了7．4％和21．3％；12mmol·L^-1供氮水平的Fm和Fv／Fm在强光胁迫时降辐减小，暗恢复时Fm和Fv／Fm恢复程度提高，而4和0．4mmol·L^-1供氮水平却相反．表明氮素供应不足时草莓叶片在富CO2环境下光合作用出现适应性下调，光抑制增强．

英文摘要：

By using PAM-2000 portable chlorophyll fluorometer and HCM-1000 photosynthesis measurement system, this paper measured the initial fluorescence （ Fo ）, maximal photochemical efficiency of PSⅡ （ Fv/Fm） , maximal fluorescence （ Fm ）, amount of inactive PS Ⅱ reaction centers （ Fi - Fo ） , proportion of QB-non-reducing PSⅡ reaction centers [ （ Fi - Fo ） / （ Fp - Fo ） ] , and net photosynthetic rate （Pn） of strawberry leaves under conditions of elevated CO2 （700 μl2L^-1） and ambient CO2（390 μl·L^-1 ） at three levels of nitrogen application （ 12, 4 and 0. 4 mmol·L^-1 ）. The results showed that there was a significant joint effect between CO2 and N on the photoinhibition of strawberry leaves. Under elevated CO2 condition, the P. in treatment 12 mmol N·L^-1 increased by 62.7%, while that in treatments 4 and 0. 4 mmol N· L^-1 decreased by 7.4% and 21.3% , respectively. When exposed to high light and subsequently recovered in dark for 4 hours, the strawberry leaves in treatment 12 mmol N ·L^-1 showed less changes of Fm and Fv/Fm in elevated CO2 than in ambient CO2, while those in treatments 4 and 0. 4 mmol N ·L^-1 were in adverse, suggesting that for the strawberry leaves in elevated CO2, nitrogen deficiency could result in an acclimatized decrease of photosynthesis and an increase of photoinhibition.