研究了在２００、３５０、５００、７００、１０００ｍｇ／ｋｇＣＯ２浓度处理下的黄瓜叶片的光合速率、呼吸速率及双磷酸核酮糖羧化加氧酶（ＲｕｂｉｓＣＯ）活性。结果表明，增加ＣＯ２浓度，可显著提高黄瓜叶片的光合速率，在强光下，效果尤其明显。黄瓜叶片光合速率对不同ＣＯ２浓度的响应都有一个由低到高再低的趋势。黄瓜叶片暗呼吸在短时间内，随ＣＯ２浓度的增加而提高，随着时间的延长（６ｍｉｎ后），各种ＣＯ２浓度下的呼吸速率都降至相似的低水平。此时，ＣＯ２浓度不影响暗呼吸速率。空气ＣＯ２浓度，细胞间隙ＣＯ２浓度与光合速率是一致的，在高ＣＯ２浓度下，气孔导度一般不是光合速率的限制因子。黄瓜叶片双磷酸核酮糖羧化酶活性，随ＣＯ２浓度的增加而提高，ＲｕＢＰ加氧酶活性降低，ＲｕＢＰ加氧酶与羧化酶之比亦下降。但在ＣＯ２浓度超过５００ｍｇ／ｋｇ后，ＲｕＢＰ羧化酶活性增长幅度变小 The leaf photosynthetic rate, respiration rate and Rubisco activity of Cu2 + were studied under 200, 350, 500, 700 and 1000 mg / kg CO2 concentrations. The results showed that increasing CO2 concentration could significantly increase the photosynthetic rate of cucumber leaves, especially in bright light. The responses of cucumber leaf photosynthesis to different CO2 concentrations showed a trend from low to high and then low. The dark respiration of cucumber leaves increased with the increase of CO2 concentration within a short period of time. With the extension of time (after 6 minutes), the respiration rate of all kinds of CO2 declines to a similar low level. At this point, the CO2 concentration does not affect the dark respiration rate. Air CO2 concentration and intercellular CO2 concentration were consistent with photosynthetic rate. Under high CO2 concentration, stomatal conductance was not the limiting factor of photosynthesis rate. The ribulose bisphosphate carboxylase activity of cucumber leaves increased with the increase of CO2 concentration, the activity of RuBP oxygenase decreased, and the ratio of RuBP oxygenase to carboxylase also decreased. However, the increase of RuBP carboxylase activity became smaller after CO2 concentration exceeded 500mg / kg