The regulation of rubisco activity in response to variation in temperature and atmospheric CO2 partial pressure in sweet potato
The regulation of rubisco activity in response to variation in temperature and atmospheric CO2 partial pressure in sweet potato
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DOI：
10.1104/pp.105.066233
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发表时间：
2005-10-01
期刊：
影响因子：
7.4
通讯作者：
Sage, RF
中科院分区：
文献类型：
--
作者：
Cen, YP;Sage, RF
在温室条件下生长的甘薯（Ipomoea batatas）中评估了净 CO2 同化速率（A）、全链电子传递速率、Rubisco 的活性和活化状态以及核酮糖-1,5-二磷酸（RuBP）和 3-磷酸甘油酸（PGA）库大小的温度响应。在光合作用的最佳热温度之上，Rubisco 的活化状态随着温度的升高而下降。在 370 mu bar 以上，将 CO2 加倍，进一步降低了活化状态，而将 CO2 减少一半，则增加了活化状态。在低温（< 16 摄氏度）下，Rubisco 的活化状态在 CO2 水平下下降，其中光合作用不受 O-2 含量减少 90% 的影响。低温下CO 2 分压的降低也增强了Rubisco的活化状态。电子传输速率显示出明显的温度响应，最佳温度与 CO2 升高时的 A 相同。 RuBP 池大小和 RuBP-to-PGA 比率随着温度升高而下降。增加 CO2 也减少了 RuBP 库的大小。这些结果与以下假设一致：高温和低温下 Rubisco 活化状态的降低是对促进 RuBP 再生速率的过程之一的限制的调节反应。为了进一步评估这种可能性，我们使用 Rubisco 容量、电子传输能力和无机磷酸盐再生能力的测量估计值来模拟 A 对温度的响应。在 CO2 浓度升高的情况下，Rubisco 的活化状态在电子传输能力预计受到限制的高温下以及无机磷酸盐再生能力受到限制的较低温度下下降。在低 CO2 条件下，预计 Rubisco 容量会限制光合作用，但在所有测量温度下均观察到 Rubisco 的完全激活。
The temperature response of net CO2 assimilation rate (A), the rate of whole-chain electron transport, the activity and activation state of Rubisco, and the pool sizes of ribulose-1,5-bisphosphate (RuBP) and 3-phosphoglyceric acid (PGA) were assessed in sweet potato ( Ipomoea batatas) grown under greenhouse conditions. Above the thermal optimum of photosynthesis, the activation state of Rubisco declined with increasing temperature. Doubling CO2 above 370 mu bar further reduced the activation state, while reducing CO2 by one-half increased it. At cool temperature (< 16 degrees C), the activation state of Rubisco declined at CO2 levels where photosynthesis was unaffected by a 90% reduction in O-2 content. Reduction of the partial pressure of CO 2 at cool temperature also enhanced the activation state of Rubisco. The rate of electron transport showed a pronounced temperature response with the same temperature optimum as A at elevated CO2. RuBP pool size and the RuBP-to-PGA ratio declined with increasing temperature. Increasing CO2 also reduced the RuBP pool size. These results are consistent with the hypothesis that the reduction in the activation state of Rubisco at high and low temperature is a regulated response to a limitation in one of the processes contributing to the rate of RuBP regeneration. To further evaluate this possibility, we used measured estimates of Rubisco capacity, electron transport capacity, and the inorganic phosphate regeneration capacity to model the response of A to temperature. At elevated CO2, the activation state of Rubisco declined at high temperatures where electron transport capacity was predicted to be limiting, and at cooler temperatures where the inorganic phosphate regeneration capacity was limiting. At low CO2, where Rubisco capacity was predicted to limit photosynthesis, full activation of Rubisco was observed at all measurement temperatures.