For most of the Phanerozoic Eon, Earth’s woody vegetation has been dominated by C3 plants - predominantly gymnosperms with angiosperms only emerging as dominant plant group CO2 declined during Cenozoic (66 Ma onward). At present, differences in carbon isotope discrimination (?13C) between angiosperm and gymnosperm are relatively small (2–3 ‰), but an increasing body evidence points to larger ac...

We compared the carbon isotope composition of ecosystem-respired CO2 (delta13C(R)) from 11 forest ecosystems in Canada and the USA and examined differences among forest delta13C(R) responses to seasonal variations in environmental conditions from May to October 2004. Our experimental approach was based on the assumption that variation in delta13C(R) is a good proxy for short-term changes in pho...

In C(4) plants, acclimation to growth at low irradiance by means of anatomical and biochemical changes to leaf tissue is considered to be limited by the need for a close interaction and coordination between bundle sheath and mesophyll cells. Here differences in relative growth rate (RGR), gas exchange, carbon isotope discrimination, photosynthetic enzyme activity, and leaf anatomy in the C(4) d...

Stable isotope analysis is a powerful tool for assessing plant carbon and water relations and their impact on biogeochemical processes at different scales. Our processbased understanding of stable isotope signals, as well as technological developments, has progressed significantly, opening new frontiers in ecological and interdisciplinary research. This has promoted the broad utilisation of car...

The husk surrounding the ear of corn/maize (Zea mays) has widely spaced veins with a number of interveinal mesophyll (M) cells and has been described as operating a partial C(3) photosynthetic pathway, in contrast to its leaves, which use the C(4) photosynthetic pathway. Here, we characterized photosynthesis in maize husk and leaf by measuring combined gas exchange and carbon isotope discrimina...

The relative carbon isotope content (V13C value) in each position of glucose from a C4 plant (maize starch) and a C3 plant (sugar beet sucrose) has been determined by stepwise chemical and biochemical degradation of the molecule and stable isotope ratio measurement of the fragments. The suitability of the degradation methods has been tested through their chemical yield and isotope balance. The ...

Stomatal conductance in trees is related to both foliar carbon-isotope abundance and stem hydraulic properties. By combining these relationships, I hypothesized that carbon-isotope abundance in foliage should vary with limitations to water movement through supporting branches. I sampled Douglas-fir branches (Pseudotsuga menziesii (Mirb.) Franco) from six sites across a climate gradient in Orego...