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Carbon dioxide stim...
Carbon dioxide stimulation of photosynthesis in Liquidambar styraciflua is not sustained during a 12-year field experiment
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- Warren, Jeffrey M. (författare)
- Oak Ridge National Laboratory, USA
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- Jensen, Anna M. (författare)
- Oak Ridge National Laboratory, USA
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- Medlyn, Belinda E. (författare)
- Macquarie University, Australia
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visa fler...
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- Norby, Richard J. (författare)
- Oak Ridge National Laboratory, USA
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- Tissue, David T. (författare)
- University of Western Sydney, Australia
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(creator_code:org_t)
- 2015-01-14
- 2015
- Engelska.
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Ingår i: AoB Plants. - : Oxford University Press. - 2041-2851. ; 7
- Relaterad länk:
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https://doi.org/10.1...
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https://academic.oup...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Elevated atmospheric CO2 (eCO2) often increases photosynthetic CO2assimilation (A) in field studies of temperate tree species. However, there is evidence that A may decline through time due to biochemical and morphological acclimation, and environmental constraints. Indeed, at the free-air CO2 enrichment (FACE) study in Oak Ridge, Tennessee, A was increased in 12-year-old sweetgum trees following 2 years of ∼40 % enhancement of CO2. A was re-assessed a decade later to determine if the initial enhancement of photosynthesis by eCO2 was sustained through time. Measurements were conducted at prevailing CO2 and temperature on detached, re-hydrated branches using a portable gas exchange system. Photosynthetic CO2 response curves (A versus the CO2 concentration in the intercellular air space (Ci); or A–Ci curves) were contrasted with earlier measurements using leaf photosynthesis model equations. Relationships between light-saturated photosynthesis (Asat), maximum electron transport rate (Jmax), maximum Rubisco activity (Vcmax), chlorophyll content and foliar nitrogen (N) were assessed. In 1999, Asat for eCO2treatments was 15.4 ± 0.8 μmol m−2 s−1, 22 % higher than aCO2treatments (P < 0.01). By 2009, Asat declined to <50 % of 1999 values, and there was no longer a significant effect of eCO2 (Asat = 6.9 or 5.7 ± 0.7 μmol m−2 s−1 for eCO2 or aCO2, respectively). In 1999, there was no treatment effect on area-based foliar N; however, by 2008, N content in eCO2 foliage was 17 % less than that in aCO2 foliage. Photosynthetic N-use efficiency (Asat : N) was greater in eCO2 in 1999 resulting in greaterAsat despite similar N content, but the enhanced efficiency in eCO2 trees was lost as foliar N declined to sub-optimal levels. There was no treatment difference in the declining linear relationships between Jmax or Vcmax with declining N, or in the ratio of Jmax : Vcmax through time. Results suggest that the initial enhancement of photosynthesis to elevated CO2 will not be sustained through time if N becomes limited.
Ämnesord
- NATURVETENSKAP -- Biologi -- Botanik (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences -- Botany (hsv//eng)
Nyckelord
- Acclimation
- down-regulation
- free-air CO2 enrichment
- nitrogen limitation
- sweetgum
- Forestry and Wood Technology
- Skog och träteknik
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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