Abstract: The light and CO2 response curves in leaves of Saraca dives were studied through potted control experiments. The results showed that the net photosynthetic rate, stomatal conductance, and transpiration rate of S. dives increased with the increase of light intensity at a certain light intensity, and showed photoinhibition under strong light. The light saturation point of S. dives was 541.23 μmol·m–2·s–1; the light compensation point was 10.20 μmol·m–2·s–1; the dark respiration rate was 1.01 μmol·m–2·s–1; the apparent quantum efficiency was 0.0247 mol·mol–1. Under the saturated light intensity, the net photosynthetic rate, water use efficiency and intercellular CO2 concentration of S. dives increased with the increase of CO2 concentration. The CO2 saturation point of S. dives was 1608.04 μmol·mol–1, the CO2 compensation point was 82.25 μmol·mol–1, the photorespiration rate was 0.94 μmol·m–2·s–1, and the apparent carboxylation efficiency was 0.0247 mol·mol–1. It provided a reference for the cultivation, popularization and application of S. dives.

Key words: Saraca dives, photosynthesis, light response curve, CO2 response curve

摘要： 通过盆栽试验研究中国无忧花(Saraca dives)叶片光合作用对光强和CO2的响应。结果表明，在一定光强范围内，中国无忧花的净光合速率、气孔导度、蒸腾速率随着光强增加而增加，但在强光照下又表现出光抑制现象。中国无忧花光饱和点为541.23 μmol·m–2·s–1，光补偿点为10.20 μmol·m–2·s–1，暗呼吸速率为1.01 μmol·m–2·s–1，表观量子效率为 0.0247 mol·mol–1。中国无忧花为阳生植物，对土壤水分需求较高。在饱和光强下，中国无忧花净光合速率、水分利用效率和胞间CO2浓度随着CO2浓度的增加呈升高趋势。中国无忧花CO2饱和点为1608.04 μmol·mol–1，CO2补偿点为 82.25 μmol·mol–1，光呼吸速率为0.94 μmol·m–2·s–1，表观羧化效率为0.0247 mol·mol–1。中国无忧花在饱和光强时具有较宽的CO2利用范围。

关键词: 中国无忧花, 光合作用, 光响应曲线, CO2响应曲线