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- Campbell, Catherine D, 1976-, et al.
(författare)
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Acclimation of photosynthesis and respiration is asynchronous in response to changes in temperature regardless of plant functional group
- 2007
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Ingår i: New Phytologist. - : Wiley-Blackwell Publishing Inc.. - 0028-646X .- 1469-8137. ; 176:2, s. 375-389
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Tidskriftsartikel (refereegranskat)abstract
- • Gas exchange, fluorescence, western blot and chemical composition analyses were combined to assess if three functional groups (forbs, grasses and evergreen trees/shrubs) differed in acclimation of leaf respiration (R) and photosynthesis (A) to a range of growth temperatures (7, 14, 21 and 28°C).• When measured at a common temperature, acclimation was greater for R than for A and differed between leaves experiencing a 10-d change in growth temperature (PE) and leaves newly developed at each temperature (ND). As a result, the R : A ratio was temperature dependent, increasing in cold-acclimated plants. The balance was largely restored in ND leaves. Acclimation responses were similar among functional groups.• Across the functional groups, cold acclimation was associated with increases in nonstructural carbohydrates and nitrogen. Cold acclimation of R was associated with an increase in abundance of alternative and/or cytochrome oxidases in a species-dependent manner. Cold acclimation of A was consistent with an initial decrease and subsequent recovery of thylakoid membrane proteins and increased abundance of proteins involved in the Calvin cycle.• Overall, the results point to striking similarities in the extent and the biochemical underpinning of acclimation of R and A among contrasting functional groups differing in overall rates of metabolism, chemical composition and leaf structure.
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| 2. |
- Högberg, Peter, et al.
(författare)
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High temporal resolution tracing of photosynthate carbon from the tree canopy to forest soil microorganisms
- 2008
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Ingår i: New Phytologist. - : New Phytologist Trust. - 0028-646X .- 1469-8137. ; 177:1, s. 220-228
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Tidskriftsartikel (refereegranskat)abstract
- • Half of the biological activity in forest soils is supported by recent tree photosynthate, but no study has traced in detail this flux of carbon from the canopy to soil microorganisms in the field.• Using 13CO2, we pulse-labelled over 1.5 h a 50-m2 patch of 4-m-tall boreal Pinus sylvestris forest in a 200-m3 chamber.• Tracer levels peaked after 24 h in soluble carbohydrates in the phloem at a height of 0.3 m, after 2–4 d in soil respiratory efflux, after 4–7 d in ectomycorrhizal roots, and after 2–4 d in soil microbial cytoplasm. Carbon in the active pool in needles, in soluble carbohydrates in phloem and in soil respiratory efflux had half-lives of 22, 17 and 35 h, respectively. Carbon in soil microbial cytoplasm had a half-life of 280 h, while the carbon in ectomycorrhizal root tips turned over much more slowly. Simultaneous labelling of the soil with showed that the ectomycorrhizal roots, which were the strongest sinks for photosynthate, were also the most active sinks for soil nitrogen.• These observations highlight the close temporal coupling between tree canopy photosynthesis and a significant fraction of soil activity in forests.
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