Canopy position affects the temperature response of leaf respiration in Populus deltoides

Publication Type  Journal Article
Year of Publication  2002
Authors  Griffin, K. L.; Turnbull, M.; Murthy, R.
Journal Title  New Phytologist
Volume  154
Issue  3
Pages  609-619
Journal Date  Jun
ISBN Number  0028-646X
Accession Number  ISI:000175786600005
Key Words  respiration; q(10); temperature; populus deltoides (cottonwood); biosphere 2; nitrogen; carbohydrates; scaling; dark respiration; maintenance respiration; photosynthetic capacity; nitrogen concentration; spatial distributions; eucalyptus-grandis; carbon g

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 10degreesC 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. (C) New Phytologist (2002) 154: 609-619.


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