High temperature acclimation of C4 photosynthesis is linked to changes in photosynthetic biochemistry
High temperature acclimation of C4 photosynthesis is linked to changes in photosynthetic biochemistry
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DOI：
10.1111/j.1365-3040.2006.01605.x
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发表时间：
2007-01-01
影响因子：
7.3
通讯作者：
Von Caemmerer, Susanne
中科院分区：
文献类型：
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作者：
Dwyer, Simon A.;Ghannoum, Oula;Von Caemmerer, Susanne
随着全球平均气温预计将增加在未来世纪，重要的是要了解的程度和机制的C-4光合适应适度增加的生长温度。为此，我们比较了两种C-4草（Panicum coloratum和Cenchrus ciliaris）和一种C-4双子叶植物（黄顶菊）在中等（25/20摄氏度，白天/晚上）或高（35/30摄氏度，白天/晚上）温度下的光合反应。在所有三个C-4物种中，CO2同化率（A）经历了显着的热驯化，因此，当在生长温度下进行比较时，A的增加小于预期，因为A对叶温的短期变化有强烈的反应。热光合驯化进一步表现为A的最适温度的增加，和叶氮含量和叶质量单位面积在高相对于中温生长的植物减少。在较高的生长温度下减少光合能力的光合组分的选择性变化的基础上。在较高温度下生长的植物有较低的核酮糖-1，5-二磷酸羧化酶/加氧酶和细胞色素f和碳酸酐酶的活性。光系统II（PSII）和磷酸酚丙酮酸羧化酶的活性不受生长温度的影响。叶绿素荧光测定结果表明，F.黄顶菊表现出PSII量子产率（Phi（PSII））的相应降低和非光化学猝灭（Phi（NPQ））的增加。它的结论是，通过这些生化变化，C-4植物保持在每个生长温度下的各种光合成分之间的平衡，尽管每个过程的温度依赖性不同。因此，在较高温度下，光合氮利用效率的增加幅度大于A。我们的研究结果表明，C-4植物的光合速率只会随着生长温度的变化而发生适度的变化，例如季节内或季节之间的预期变化，或者由于全球气候变化而预期的变暖。
With average global temperatures predicted to increase over the next century, it is important to understand the extent and mechanisms of C-4 photosynthetic acclimation to modest increases in growth temperature. To this end, we compared the photosynthetic responses of two C-4 grasses (Panicum coloratum and Cenchrus ciliaris) and one C-4 dicot (Flaveria bidentis) to growth at moderate (25/20 degrees C, day/night) or high (35/30 degrees C, day/night) temperatures. In all three C-4 species, CO2 assimilation rates (A) underwent significant thermal acclimation, such that when compared at growth temperatures, A increased less than what would be expected given the strong response of A to short-term changes in leaf temperature. Thermal photosynthetic acclimation was further manifested by an increase in the temperature optima of A, and a decrease in leaf nitrogen content and leaf mass per area in the high-relative to the moderate-temperature-grown plants. Reduced photosynthetic capacity at the higher growth temperature was underpinned by selective changes in photosynthetic components. Plants grown at the higher temperature had lower amounts of ribulose-1,5-bisphosphate carboxylase/oxygenase and cytochrome f and activity of carbonic anhydrase. The activities of photosystem II (PSII) and phosphenolpyruvate carboxylase were not affected by growth temperature. Chlorophyll fluorescence measurements of F. bidentis showed a corresponding decrease in the quantum yield of PSII (Phi(PSII)) and an increase in non-photochemical quenching (Phi(NPQ)). It is concluded that through these biochemical changes, C-4 plants maintain the balance between the various photosynthetic components at each growth temperature, despite the differing temperature dependence of each process. As such, at higher temperatures photosynthetic nitrogen use efficiency increases more than A. Our results suggest C-4 plants will show only modest changes in photosynthetic rates in response to changes in growth temperature, such as those expected within or between seasons, or the warming anticipated as a result of global climate change.