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isotopic discrimination


'isotopic discrimination' can also refer to...

isotopic discrimination

isotopic discrimination

Effects of branch length on carbon isotope discrimination in Pinus radiata

Carbon isotope discrimination as a tool to explore C4 photosynthesis

Stable carbon isotope discrimination: an indicator of cumulative salinity and boron stress in Eucalyptus camaldulensis

Carbon isotope discrimination in western hemlock and its relationship to mineral nutrition and growth

Growth in two common gardens reveals species by environment interaction in carbon isotope discrimination of Eucalyptus

Associations between growth, wood anatomy, carbon isotope discrimination and mortality in a Quercus robur forest

Carbon isotope discrimination and water stress in trembling aspen following variable retention harvesting

Carbon isotope discrimination during branch photosynthesis of Fagus sylvatica: field measurements using laser spectrometry

Yield, carbon isotope discrimination, canopy reflectance and cuticular conductance of barley isolines of differing glaucousness

Seasonal and interannual variations in carbon isotope discrimination in a maritime pine (Pinus pinaster) stand assessed from the isotopic composition of cellulose in annual rings

Stable sulfur isotope fractionation and discrimination between the sulfur atoms of thiosulfate during oxidation by Halothiobacillus neapolitanus

Carbon isotope discrimination as a diagnostic tool for C4 photosynthesis in C3-C4 intermediate species

Ecophysiology of Acer rubrum seedlings from contrasting hydrologic habitats: growth, gas exchange, tissue water relations, abscisic acid and carbon isotope discrimination

Competition for water between walnut seedlings (Juglans regia) and rye grass (Lolium perenne) assessed by carbon isotope discrimination and δ18O enrichment

Relationships between gas exchange and carbon isotope discrimination of Sitka × interior spruce introgressive genotypes and ribosomal DNA markers

Gas exchange and carbon isotope discrimination of Juniperus osteosperma and Juniperus occidentalis across environmental gradients in the Great Basin of western North America

Variations in bulk leaf carbon isotope discrimination, growth and related leaf traits among three Populus nigra L. populations

 

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The uptake or assimilation by living organisms of a particular isotope in preference to another isotope of the same element. A well-known example in nature is the preferential fixation by photosynthetic organisms of the lighter (and vastly more abundant) isotope carbon-12 compared with the heavier carbon-13. The relative abundance of these two stable isotopes in biological material, whether living or dead, differs from that in the atmosphere and according to various factors, including the type of ecosystem, season, and atmospheric conditions. A record of these changes, based on preserved organic material, can provide insights into historical climatic conditions. In plants isotopic discrimination occurs chiefly because carbon dioxide (CO2) containing 13C diffuses more slowly than lighter CO2 containing 12C and also because the enzymes involved in photosynthetic carbon fixation discriminate between the two isotopes, particularly rubisco, the first enzyme to encounter CO2 in C3 plants (see C3 pathway). 12C/13C isotopic discrimination is less pronounced in C4 plants, in which CO2 is first incorporated by the C4 pathway. This gives C3 and C4 plants characteristically different isotopic signatures. Determination of 12C/13C ratios in plant material using mass spectrometry is informative about plant physiology and atmospheric conditions. For example, it indicates whether the stomata of a plant were mainly open or mainly closed during its lifetime, and hence whether conditions were likely to have been moist or dry.

Subjects: Biological Sciences.


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