摘要： 研究了在200、350、500、700、1000mg/kg CO₂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，可显着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

关键词: 黄瓜, 二氧化碳浓度, 光合速率, 呼吸速率

Abstract: This experiment dealt with the influence of CO₂ at the concentrations of 200,350,500,700 and 1000 mg/kg on photosynthetic and respiratory rates and RubisCO activity. The results showed that the CO₂ enrichment did increase the photosynthetic rate of upper leaves of cucumber, especially under intensive light conditions. The response of photosynthetic rate to the different CO₂ concentrations appeared low at the beginning, then higher and finally lower. The respiratory rates of these leaves increased rapidly with the enrichment of CO₂, until 6 min. Later all dropped to their lowest levels despite the CO₂ concentrations, from when there was no notable effect of CO₂ concentrations on the respiratory rates. The photosynthesis rate was positively correlated with the atmospheric and intercellular CO₂ concentrations. Generally the stomatal conductance was not a factor to inhibit photosynthetic at high CO₂ concentrations. The RuBP carboxylase activity was enhanced while RuBP oxygenase activity and also the ratio of the former to the latter decreased. Nevertheless,when the CO₂ concentrations were over 500mg/kg,the activity of RuBP carboxylase increased slightly.

Key words: Cucumber, CO₂ concentration, Photosynthetic rate, Respiratory rate

中图分类号: 

• S642.201