水稻叶片生育过程中RubisCO活性与光合、光呼吸的关系

The Relationships Between Ribulose-1,5-Bisphosphate Carboxylase-Oxygenase Activity and Photosynthesis and Photorespiration in Rice Leaves During the Growth Process

水稻生育过程中，ＲｕＢＰ羧化酶活性与光合速率、ＲｕＢＰ加氧酶活性与光呼吸速率、ＲｕＢＰ羧化酶活性与加氢酶活性以及光合速率与光呼吸速率之间是相关的。籼型品种与粳型品种间酶活性的高低及光合、光呼吸速率的高低基本一致，籼型三系杂交稻（Ｆ１）无明显的光合优势。酶的羧化活性的高低只在一定范围内与光合速率的高低平行。在正常生育条件下，酶蛋白的数量不是水稻光合速率的限制因子。

Activities ofribulose-1,5 bisphosphate carboxylase-oxygenase(EC.4.1.1.39.),soluble protein contents and rates of photosynthesis and photorespiration were measured in leaves of rice plants (Oryza sativa L.cv.Kinmaze,Guangiiuai No,4,Shanyou No.63) in different leaf poSitions and leaf ages.The results showed that photosynthetic rate and RuBP carboxylase activities did not change significantly with the rise of leaf position(Fig.2,4), but decreased with the advance of leaf age(Fig.1,3).The photorespiratory rate declined less than the Photosynthetic rate(Fig.3-B),which could be explained by the fact that the variations of the ratio of RuBP oxygenase/carboxylase activities(%) which is considered to be reflecting Photorespiratory caP8city,increased from the younger leaves to older leaves(Fig.1-B).Correlation analysis showed that RuBP carboxylase activity vs.photosynthetic rate,RuBP carboxylase activity vs.RuBP oxygenase activity and RuBP carboxylase activity vs.soluble protein content were significantly correlated(Table 1).The activity of RuBP oxygenase was also significantly corrlated with photorespiratory rate.All these results seem to indicate that there is close linkage between these photosynthetic characteristics during the growth of rice plants.