RECORD
Photosynthetic Refixation in Branches of Western White Pine
- Title:
- Photosynthetic Refixation in Branches of Western White Pine
- Creator:
- Cernusak, L.A.; Marshall, J.D.
- Date Created:
- 2000-06
- Description:
- We investigated the functional controls on light-dependent refixation of respired CO2 in photosynthetic bark of Western White Pine (Pinus monticola Dougl. ex D. Don) branches. Gross photosynthesis increased with increasing intensity of photosynthetically active radiation (PAR) to > 2000 μmol m-2 s-1 and with increasing bark surface temperature from 15 to > 45 ⚬C. Maximum observed refixation rates were 76 ± 3% (mean ± SE) of dark respiration. At a given temperature and irradiance, dark respiration rate was the physiological parameter that correlated most strongly with gross photosynthesis (R = 0.89, P < 0.0001, n = 43). Dark respiration rates varied 20-fold among branches. Over this range, refixation averaged 55 ± 2% of dark respiration at 25 ⚬C and 1000 μmol PAR m-2 s-1. However, refixation was not correlated with internal CO2 concentrations in illuminated branches; these concentrations remained fairly constant. Specific bark area, bark conductance to water vapour, bark chlorophyll a/b ratio, and bark nitrogen concentration varied markedly with canopy depth in mature trees. Results are summarized in a simple model of refixation driven by light, temperature and dark respiration rate. The model may prove useful in assessing the quantitative significance of refixation in the carbon balance of forest trees.
- Document Type:
- Research Article
- Subjects:
- UIEF photosynthetic refixation western white pine carbon refixation respiration gross photosynthesis net photosynthesis dark respiration forest ecology
- Location:
- UIEF
- Latitude:
- 46.833333
- Longitude:
- -116.716667
- Publisher:
- British Ecological Association
- Department:
- Forest, Rangeland, and Fire Sciences
- Type:
- Text
Source
- Preferred Citation:
- "Photosynthetic Refixation in Branches of Western White Pine", UIEF Research Exchange, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/uief/items/uief_0183.html
Rights
- Rights:
- In copyright, educational use permitted.
- Standardized Rights:
- http://rightsstatements.org/vocab/InC-EDU/1.0/