Seasonal change in the balance between capacities of RuBP carboxylation and RuBP regeneration affects CO2 response of photosynthesis in Polygonum cuspidatum
Seasonal change in the balance between capacities of RuBP carboxylation and RuBP regeneration affects CO2 response of photosynthesis in Polygonum cuspidatum
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DOI：
10.1093/jxb/eri052
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发表时间：
2005-02-01
影响因子：
6.9
通讯作者：
Hirose, T
中科院分区：
文献类型：
--
作者：
Onoda, Y;Hikosaka, K;Hirose, T
RuBP(核酮糖-1，5-二磷酸)羧化能力(V-cmxax)和RuBP再生能力(表示为最大电子传递速率J(Max))之间的平衡决定了光合作用速率对CO2的依赖。由于这种平衡随生长温度的变化而变化，因此验证了气温的季节性变化影响平衡并调节光合作用的二氧化碳响应的假设。测定了夏秋两季生长在不同CO2浓度(370和700mmolmol.-1)下的虎杖幼叶和老叶的V-cmax和J(Max)。CO2浓度升高有降低V-cmax和J(Max)的趋势，但不改变J(Max)：V-cmax的比值。另一方面，季节环境改变了这一比率，使秋季叶片的J(Max)：V-CMAX比值高于夏季叶片。这种变化使得秋季的光合作用更依赖于二氧化碳浓度。因此，当比较生长CO2浓度下的光合作用速率时，幼秋对光合作用的刺激作用大于幼夏叶片。在老秋叶中，J(Max)：V-CMAX比值的变化对光合作用的刺激作用被CO2浓度升高下叶片的加速衰老所部分抵消。在两个季节和两种CO2浓度下，V-cmax与Rubisco、J(Max)与细胞色素f含量呈极显著正相关。这些结果表明，气候的季节变化影响光合作用蛋白质的相对数量，进而影响光合作用的二氧化碳响应。
The balance between the capacities of RuBP (ribulose-1,5-bisphosphate) carboxylation (V-cmxax) and RuBP regeneration (expressed as the maximum electron transport rate, J(max)) determines the CO2 dependence of the photosynthetic rate. As it has been suggested that this balance changes depending on the growth temperature, the hypothesis that the seasonal change in air temperature affects the balance and modulates the CO2 response of photosynthesis was tested. V-cmax and J(max) were determined in summer and autumn for young and old leaves of Polygonum cuspidatum grown at two CO2 concentrations (370 and 700 mumol mol(-1)). Elevated CO2 concentration tended to reduce both V-cmax and J(max) without changing the J(max):V-cmax ratio. The seasonal environment, on the other hand, altered the ratio such that the J(max):V-cmax ratio was higher in autumn leaves than summer leaves. This alternation made the photosynthetic rate more dependent on CO2 concentration in autumn. Therefore, when photosynthetic rates were compared at growth CO2 concentration, the stimulation in photosynthetic rate was higher in young-autumn than in young-summer leaves. In old-autumn leaves, the stimulation of photosynthesis brought by a change in the J(max): V-cmax ratio was partly offset by accelerated leaf senescence under elevated CO2. Across the two seasons and the two CO2 concentrations, V-cmax was strongly correlated with Rubisco and J(max) with cytochrome f content. These results suggest that seasonal change in climate affects the relative amounts of photosynthetic proteins, which in turn affect the CO2 response of photosynthesis.