isotopic discrimination

'isotopic discrimination' can also refer to...

isotopic discrimination

isotopic discrimination

Carbon isotope discrimination as a tool to explore C4 photosynthesis

Effects of branch length on carbon isotope discrimination in Pinus radiata

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

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

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

Discrimination of wild and cultured Japanese eels based on otolith stable isotope ratios

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

The effect of transient and continuous drought on yield, photosynthesis and carbon isotope discrimination in sugar beet (Beta vulgaris L.)

Associations between partitioning of carboxylase activity and bundle sheath leakiness to CO2, carbon isotope discrimination, photosynthesis, and growth in sugarcane

Exploiting transplastomically modified Rubisco to rapidly measure natural diversity in its carbon isotope discrimination using tuneable diode laser spectroscopy

The efficiency of C4 photosynthesis under low light conditions: assumptions and calculations with CO2 isotope discrimination

Variation in carbon isotope discrimination in Cleistogenes squarrosa (Trin.) Keng: patterns and drivers at tiller, local, catchment, and regional scales


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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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