中文摘要：

利用低氧法（2% O2）研究了大豆叶片光呼吸速率（Rp）对光强和CO2浓度的响应。结果表明：当光合有效辐射强度（PAR）小于600μmol·m^-2·s^-1时,大豆叶片的Rp随光强的升高而几乎直线增加;当PAR约为1200μmol·m^-2·s^-1时,Rp达到最大值（12.69·mol CO2·m^-2·s^-1）,随后Rp随PAR的升高呈下降趋势;构建的光呼吸速率与光强的方程式拟合结果表明,大豆叶片最大光呼吸速率为13.42·mol CO2·m^-2·s^-1,其对应的光强为1207.74·mol·m^-2·s^-1,该拟合值与实际测量值极为吻合（P＞0.05）;当PAR一定（2000μmol·m^-2·s^-1）时,随着CO2浓度的增加（0-1200μmol·mol^-1）,大豆叶片的Rp呈先升高后下降变化,在600μmol·mol^-1时达到最大值（9.97·mol CO2·m^-2·s^-1）;构建的光呼吸速率与CO2浓度的方程式拟合结果表明,大豆叶片最大光呼吸速率为10.21·mol CO2·m^-2·s^-1,其对应的外界CO2浓度为625.74·mol·mol^-1。该拟合值也与实际测量值极为吻合（P＂0.05）。本文所构建的方程式可较好地拟合光呼吸速率对不同光强和不同CO2浓度的响应,这对定量研究光呼吸提供了强有力的手段。

英文摘要：

The light and CO2responses of photorespiration rate （Rp） of soybean （Glycine max） leaves were studied under 2% and 21% O2. The results showed that Rp of soybean leaves increased almost linearly with increasing photosynthetically active radiation （PAR） when PAR was less than 600 μmol·m^-2·s^-1; Rp reached the maximum value of 12.69 μmol CO2·m^-2·s^-1 when PAR was about 1200 μmol·m^-2·s^-1, and then Rp decreased with increasing PAR. The function relationship between Rp and PAR was constructed. The fitted result showed that the maximum value of Rp （Ppmax） was 13.42 μmol CO2·m^-2·s^-1, and the light intensity corresponding to Ppmax was 1207.74 μmol·m^-2·s^-1. The fitted values were extremely in agreement with the measured values （P〈0.05）. As air CO2 concentration （Ca） （0-1200 μmol·mol-1） increased, Rp of soybean leaves increased firstly and then decreased. It reached a maximum value of 9.97 μmol CO2·m^-2·s^-1 when Ca was about 600 μmol·mol-1. The function relationship between Rp and Ca was also constructed. The fitted result showed that the Ppmax was 10.21 SymbolmA@mol CO2·m^-2·s^-1, and the Ca corresponding to the Ppmax was 625.74 μmol·mol-1. The fitted values also accorded with the measured values （P〈0.05）. Thus, it can be concluded that the constructed function relationships between Rp and PAR and between Rp andCa would provide a powerful means for the quantitative study of photorespiration of plant leaves.