Griffin Kevin L, Turnbull Matthew, Murthy Ramesh
Department of Earth and Environmental Sciences, Columbia University, Palisades, NY 10964, USA.
Department of Plant and Microbial Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
New Phytol. 2002 Jun;154(3):609-619. doi: 10.1046/j.1469-8137.2002.00410.x.
• Leaf respiration and its temperature response were measured in 4-m-tall, 1-yr-old Populus deltoides trees to assess the effect of within-canopy distribution of respiratory physiology on total foliar C exchange of a model ecosystem at Biosphere 2. • Over the course of five nights, air temperature was varied over a 10°C range and the steady-state rate of leaf respiration was measured. These data were then modeled to calculate the temperature response of leaf and canopy respiration. • Results indicate that there is considerable within-canopy variation in both the rate of respiration and its temperature response and that these variables are most strongly related to leaf carbohydrate and leaf N. Scaling these results to the ecosystem level demonstrates the importance of quantifying the vertical distribution of respiratory physiology, particularly at lower temperatures. • Simplifying assumptions regarding the variation in respiration and its temperature response with canopy height tend to result in an underestimation of the actual C loss if the assumptions are based on lower- or mid-canopy leaf physiology, but overestimate C loss if the model assumptions are based on upper-canopy physiology.
• 在生物圈2号中，对4米高、树龄1年的三角叶杨进行了叶片呼吸及其温度响应的测量，以评估呼吸生理的冠层内分布对模型生态系统总叶碳交换的影响。
• 在五个夜晚的过程中，空气温度在10°C范围内变化，并测量了叶片呼吸的稳态速率。然后对这些数据进行建模，以计算叶片和冠层呼吸的温度响应。
• 结果表明，冠层内呼吸速率及其温度响应均存在相当大的差异，并且这些变量与叶片碳水化合物和叶片氮的关系最为密切。将这些结果扩展到生态系统水平表明，量化呼吸生理的垂直分布非常重要，尤其是在较低温度下。
• 如果关于呼吸及其温度响应随冠层高度变化的简化假设基于冠层下部或中部叶片生理，则往往会低估实际的碳损失，但如果模型假设基于冠层上部生理，则会高估碳损失。
