نتایج جستجو برای: carbon isotope discrimination delta

تعداد نتایج: 423589  

Journal: :PloS one 2015
Polona Hafner Jožica Gričar Mitja Skudnik Tom Levanič

We analysed two groups of Quercus robur trees, growing at nearby plots with different micro-location condition (W-wet and D-dry) in the floodplain Krakovo forest, Slovenia. In the study we compared the growth response of two different tree groups to environmental variables, the potential signal stored in earlywood (EW) structure and the potential difference of the information stored in carbon i...

Journal: :Plant, cell & environment 2008
Arthur Gessler Guillaume Tcherkez Andreas D Peuke Jaleh Ghashghaie Graham D Farquhar

Carbon isotope fractionation in metabolic processes following carboxylation of ribulose-1,5-bisphosphate (RuBP) is not as well described as the discrimination during photosynthetic CO(2) fixation. However, post-carboxylation fractionation can influence the diel variation of delta(13)C of leaf-exported organic matter and can cause inter-organ differences in delta(13)C. To obtain a more mechanist...

2017
Shaena Montanari

Stable isotope analysis of feces can provide a non-invasive method for tracking the dietary habits of nearly any mammalian species. While fecal samples are often collected for macroscopic and genetic study, stable isotope analysis can also be applied to expand the knowledge of species-specific dietary ecology. It is somewhat unclear how digestion changes the isotope ratios of animals' diets, so...

Journal: :Rapid communications in mass spectrometry : RCM 2009
Wu Wang Li Li Huaijian Li Dongping Zhang Shen Wen Wanglu Jia Bangjin Wang Guo ying Sheng Jiamo Fu

The stable carbon isotope compositions of tetrols, erythritol and threitol were determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Using four tetrols with various delta(13)C values derivatized by methylboronic acid, the carbon isotope analysis method achieved excellent reproducibility and high accuracy. There was no carbon isotopic fractionation during the ...

Journal: :Tree physiology 2007
Kevin D Bladon Uldis Silins Simon M Landhäusser Christian Messier Victor J Lieffers

Variable retention harvesting (VRH) has been proposed as a silvicultural practice to maintain biodiversity and ecosystem integrity. No previous study has examined tree carbon isotope discrimination to provide insights into water stress that could lead to dieback and mortality of trees following VRH. We measured and compared the carbon isotope ratios (delta(13)C) in stem wood of trembling aspen ...

Journal: :Tree physiology 1998
J. R. Ehleringer C. S. Cook

Isotope ratio analyses of atmospheric CO(2) at natural abundance have significant potential for contributing to our understanding of photosynthetic and respiration processes in forest ecosystems. Recent advances in isotope ratio mass spectrometry allow for rapid, on-line analysis of small volumes of CO(2) in air, and open new research opportunities at the ecophysiological, whole-organism, and a...

Journal: :Plant physiology 1988
J Masle G D Farquhar

The ratio of carbon accumulation to transpiration, W, of wheat (Triticum aestivum L.) seedlings increased with increasing soil strength, measured as soil penetrometer resistance, and this was already apparent at the two leaf stage. The ratio was negatively correlated with carbon isotope discrimination, in accord with theory. This means that decrease in intercellular partial pressure of CO(2) ac...

Journal: :Applied and environmental microbiology 1996
B Gu V Alexander

The carbon isotope composition of photosynthetic organisms reflects the (delta)(sup13)C of their inorganic carbon sources. The large difference between (delta)(sup13)C in cyanobacterial surface scums (-25 to -18(permil)) and subsurface blooms (-34 to -30(permil)) in a subarctic lake indicates direct atmospheric CO(inf2) fixation by the scums.

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2003
Bainian Sun David L Dilcher David J Beerling Chengjun Zhang Defei Yan Elizabeth Kowalski

Fossil leaves assigned to the genus Ginkgo are increasingly being used to reconstruct Mesozoic and Tertiary environments based on their stomatal and carbon isotopic characteristics. We sought to provide a more secure basis for understanding variations seen in the plant fossil record by determining the natural variability of these properties of sun and shade leaf morphotypes of Ginkgo biloba tre...

Journal: :Tree physiology 2007
Barbara J Bond Nicole M Czarnomski Clifton Cooper Michael E Day Michael S Greenwood

The characteristic decline in height growth that occurs over a tree's lifespan is often called "age-related decline." But is the reduction in height growth in aging trees a function of age or of size? We grafted shoot tips across different ages and sizes of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees to determine whether the decline in height growth is mediated by tree size or by t...

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