Seasonal changes in the temperature response of photosynthesis in canopy leaves of Quercus crispula in a cool-temperate forest
Seasonal changes in the temperature response of photosynthesis in canopy leaves of Quercus crispula in a cool-temperate forest
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DOI：
10.1093/treephys/27.7.1035
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发表时间：
2007-07-01
期刊：
影响因子：
4
通讯作者：
Hiura, Tsutom
中科院分区：
文献类型：
--
作者：
Hikosaka, Kouki;Nabeshima, Eri;Hiura, Tsutom
了解冠层叶片光合特性的季节变化是建立森林碳平衡模型的必要条件。我们研究了季节性变化的气体交换特性，与光合作用的温度依赖性在冠层叶片的皱皮栎，在日本的冷温带森林中最丰富的物种之一。光合速率和核酮糖-1，5-二磷酸（RuBP）羧化能力（V-cmax）在20 ℃时从6月到8月呈上升趋势，9月又呈下降趋势。V-cmax的活化能（V-cmax的温度依赖性）在夏季最高，表明此时V-cmax对叶温最敏感。V-cmax的活化能与生长温度显著相关。其他参数相关的光合作用的温度依赖性，如细胞间CO2分压和RuBP再生能力的温度依赖性，没有表现出明显的季节性趋势。说明叶片衰老影响RuBP羧化与再生之间的平衡。模型模拟结果表明，夏季光合速率最高，光合最适温度最高。
Understanding seasonal changes in photosynthetic characteristics of canopy leaves is indispensable for modeling the carbon balance in forests. We studied seasonal changes in gas exchange characteristics that are related to the temperature dependence of photosynthesis in canopy leaves of Quercus crispula Blume, one of the most abundant species in cool-temperate forests in Japan. Photosynthetic rate and ribulose- 1,5-bisphosphate (RuBP) carboxylation capacity (V-cmax) at 20 degrees C increased from June to August and then decreased in September. The activation energy of V-cmax a measure of the temperature dependence of V-cmax, was highest in summer, indicating that V-cmax was most sensitive to leaf temperature at this time. The activation energy of V-cmax was significantly correlated with growth temperature. Other parameters related to the temperature dependence of photosynthesis, such as intercellular CO2 partial pressure and temperature dependence of RuBP regeneration capacity, showed no clear seasonal trend. It was suggested that leaf senescence affected the balance between carboxylation and regeneration of RuBP. The model simulation showed that photosynthetic rate and its optimal temperature were highest in summer.