高温和加富CO2温室中黄瓜Rubisco活化酶与光合作用的关系

 以温室嫁接黄瓜为试材，研究高温和加富CO₂条件下叶片净光合速率、Rubisco活性、Rubisco活化酶活性、蒸腾速率、胞间CO₂浓度的日变化规律及其相互关系。旨为高温季节温室黄瓜高产优质栽培提供理论依据和实践支持。研究结果表明：①高温 + CO₂条件下，净光合速率、Rubisco活性和Rubisco活化酶活性存在明显的光合日变化，均呈双峰曲线，存在“午休”现象，但与对照相比全天的数值明显增加，其中净光合速率在10：00、11：00、12：00、13：00、14：00和15：00时分别比对照高22%、47%、37%、27%、39%和28%；Rubisco活性在9：00、10：00、11：00、12：00、13：00、14：00和15：00时分别比对照高51%、69%、70%、42%、77%、61%和59%；RCA活性在8：00、9：00、10：00、11：00、12：00、13：00、14：00、15：00和16：00时比对照分别升高了40%、39%、23%、41%、43%、31%、60%、60%和54%；② Rubisco活化酶对光合速率的直接影响较小，其本质是调节Rubisco活性，从而影响光合作用；③高温 + CO₂可以有效提高Rubisco活化酶活力以及胞间CO₂浓度，从而提高光合速率。

Correlation Between Rubisco Activase and Photosynthesis of Cucumber in Greenhouse Under High Temperature and Elevated CO2

The diurnal changes of photosynthetic rate，Rubisco activity，Rubisco activase（RAC）activity，transpiration rate and intercellular CO2 concentration of cucumber leaves in greenhouse were studied under high temperature and elevated CO2，and the relationship between photosynthetic rate and Rubisco activity，Rubisco activase activity were also analyzed. Main results are as follows：①The photosynthetic rate，Rubisco activity and Rubisco activase activity showed distinct diurnal changes under high temperature and elevated CO2. Compared with the control，high temperature and elevated CO2 led to a remarkable increase in values of the photosynthetic rate，Rubisco activity and Rubisco activase activity. ②Rubisco activase activity had an effect on photosynthetic rate by adjusting Rubisco activity. ③Rubiscoactivase activity and intercellular CO2 concentration were increased by high temperature and elevated CO2，thus photosynthetic rate was improved.