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首页> 外文期刊>Journal of Experimental Botany >Rubisco, Rubisco activase, and global climate change
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Rubisco, Rubisco activase, and global climate change

机译：Rubisco，Rubisco激活酶与全球气候变化

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Global warming and the rise in atmospheric CO2 will increase the operating temperature of leaves in coming decades, often well above the thermal optimum for photosynthesis. Presently, there is controversy over the limiting processes controlling photosynthesis at elevated temperature. Leading models propose that the reduction in photosynthesis at elevated temperature is a function of either declining capacity of electron transport to regenerate RuBP, or reductions in the capacity of Rubisco activase to maintain Rubisco in an active configuration. Identifying which of these processes is the principal limitation at elevated temperature is complicated because each may be regulated in response to a limitation in the other. Biochemical and gas exchange assessments can disentangle these photosynthetic limitations; however, comprehensive assessments are often difficult and, for many species, virtually impossible. It is proposed that measurement of the initial slope of the CO2 response of photosynthesis (the A/Ci response) can be a useful means to screen for Rubisco activase limitations. This is because a reduction in the Rubisco activation state should be most apparent at low CO2 when Rubisco capacity is generally limiting. In sweet potato, spinach, and tobacco, the initial slope of the A/Ci response shows no evidence of activase limitations at high temperature, as the slope can be accurately modelled using the kinetic parameters of fully activated Rubisco. In black spruce (Picea mariana), a reduction in the initial slope above 30 °C cannot be explained by the known kinetics of fully activated Rubisco, indicating that activase may be limiting at high temperatures. Because black spruce is the dominant species in the boreal forest of North America, Rubisco activase may be an unusually important factor determining the response of the boreal biome to climate change.
机译：全球变暖和大气中CO 2 的升高将在未来几十年内提高叶片的工作温度，通常远高于光合作用的最佳温度。目前，关于在高温下控制光合作用的限制过程存在争议。领先的模型提出，高温下光合作用的降低是电子传递再生RuBP的能力下降或Rubisco激活酶将Rubisco保持在活性构型的能力降低的函数。识别这些过程中的哪一个是高温下的主要限制是很复杂的，因为可以响应另一个限制来调节每个过程。生化和气体交换评估可以消除这些光合限制。但是，全面评估通常是困难的，而且对于许多物种而言，几乎是不可能的。提出测量光合作用的CO 2 响应的初始斜率（A / C i 响应）可以作为筛选Rubisco激活酶限制的有用手段。这是因为通常在Rubisco容量受到限制的情况下，在低CO 2 时，Rubisco活化态的降低最明显。在甘薯，菠菜和烟草中，A / C i 反应的初始斜率没有显示激活酶在高温下受到限制的迹象，因为可以使用完全活化的动力学参数准确地模拟该斜率。鲁比斯科。在黑云杉（Picea mariana）中，无法通过完全活化的Rubisco的已知动力学解释高于30°C的初始斜率的降低，这表明活化酶可能在高温下受到限制。由于黑云杉是北美北方森林中的主要物种，因此Rubisco激活酶可能是决定北方生物群落对气候变化响应的异常重要因素。

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