Department of Agronomy, University of Illinois at Urbana-Champaign, S-215 Turner Hall, Urbana, Illinois 61801.
Plant Physiol. 1988 Nov;88(3):850-3. doi: 10.1104/pp.88.3.850.
Since activation of ribulose bisphosphate carboxylase (rubisco) by rubisco activase is sensitive to ATP and ADP in vitro, we aimed to test the correlation between ATP level and rubisco activation state in intact leaves of Spinacia oleracea L. in response to changes in irradiance and after feeding the electron acceptor methyl viologen. Leaves were exposed to various irradiances for 45 minutes at atmospheric partial pressures of CO(2) and O(2). After measuring the rate of CO(2) assimilation, leaves were freeze-clamped in situ and the punched discs assayed for rubisco activity, and amounts of ribulose bisphosphate (RuBP), ATP, and ADP. The photosynthetic rate and the activation state of rubisco increased with increasing irradiance but the levels of RuBP, ATP, and ADP were not greatly affected. Methyl viologen fed leaves under low irradiance had rubisco activation states of 93% compared to 51% in control leaves. The ATP content of the leaves was also significantly higher and the ratio of ATP to ADP was 4.1 in methyl viologen fed leaves compared to 2.2 in control leaves. From these results and other published results we conclude that a correlation between ATP level and rubisco activation can be observed in intact leaves, but that during changes in irradiance some additional factors are involved in regulating rubisco activation.
由于核酮糖-1,5-二磷酸羧化酶（Rubisco）在体外对Rubisco 激活酶的激活对 ATP 和 ADP 敏感，我们旨在测试在强光和电子受体甲紫精喂养后，响应辐照度变化的情况下，完整的菠菜（Spinacia oleracea L.）叶片中 ATP 水平与 Rubisco 激活状态之间的相关性。叶片在大气 CO2 和 O2 分压下，在不同的辐照度下暴露 45 分钟。测量 CO2 同化率后，叶片原位冷冻并对打孔盘进行 Rubisco 活性和核酮糖-1,5-二磷酸（RuBP）、ATP 和 ADP 含量的测定。随着辐照度的增加，光合速率和 Rubisco 的激活状态增加，但 RuBP、ATP 和 ADP 的水平没有受到很大影响。在低辐照度下喂养的甲紫精叶片的 Rubisco 激活状态为 93%，而对照叶片为 51%。与对照叶片相比，甲紫精喂养叶片的叶片 ATP 含量也显著增加，且 ATP 与 ADP 的比值为 4.1，而对照叶片为 2.2。根据这些结果和其他已发表的结果，我们得出结论，在完整叶片中可以观察到 ATP 水平与 Rubisco 激活之间的相关性，但在辐照度变化期间，一些其他因素参与了 Rubisco 激活的调节。
