Tree-ring δC is widely employed in ecophysiological studies, because it represents an integra-ted proxy of the ratio between photosynthesis (A) and stomatal conductance (g), which expresses the intrin-sic water use efficiency (iWUE), strongly affected by the environmental conditions experienced by the plant during its life span. Tree-ring δC also reflects long term variations of atmospheric CO2...

Understanding how carbon dioxide (CO2) flux from ecosystems feeds back to climate warming depends in part on our ability to quantify the efficiency with which microorganisms convert organic carbon (C) into either biomass or CO2. Quantifying ecosystem-level respiratory CO2 losses often also requires assumptions about stable C isotope fractionations associated with the microbial transformation of...

The responses of gas exchange and water use efficiency to nitrogen nutrition for winter wheat were investigated under well-watered and drought conditions. The photosynthetic gas exchange parameters of winter wheat are remarkably improved by water and nitrogen nutrition and the regulative capability of nitrogen nutrition is influenced by water status. The effects of nitrogen nutrition on photosy...

Influence of long-term changes in climate and CO2 concentration on intrinsic water-use efficiency (iWUE), defined as the ratio between net photosynthesis (A) and leaf conductance (g), and tree growth remain not fully revealed in humid subtropical China, which is distinct from other arid subtropical areas with dense coverage of broadleaf forests. This study presented the first tree-ring stable c...

We studied the benzylsuccinate synthase (Bss) reaction mechanism with respect to the hydrogen-carbon bond cleavage at the methyl group of toluene by using different stable isotope tools. Λ values (slopes of linear regression curves for carbon and hydrogen discrimination) for two-dimensional compound-specific stable isotope analysis (2D-CSIA) of toluene activation by Bss-containing cell extracts...

It is well known that whole-plant water-use efficiency (transpiration efficiency of carbon gain, TE(C)) varies among plant species with different photosynthetic pathways. However, less is known of such variation among tree species within the C(3) group. Here we measured the TE(C) of seven C(3) tropical tree species. Isotopic analyses (delta(13)C, delta(18)O, and delta(15)N) and elemental analys...

Understanding the influences of climatic changes on water use efficiency (WUE) of Tibetan alpine meadows is important for predicting their long-term net primary productivity (NPP) because they are considered very sensitive to climate change. Here, we collected wool materials produced from 1962 to 2010 and investigated the long-term WUE of an alpine meadow in Tibet on basis of the carbon isotope...

  In a three-year (2004-2006), field experiment, we aimed to study changes in leaf physiological traits (leaf water potential-Ψleaf, leaf water content-LWC, carbon isotope discrimination-Δ, specific leaf area-SLA, chlorophyll content as assessed by SPAD and modified SPAD-MSPAD) and elemental composition (K, Na, Ca, Mg, K/Na, Ca/Mg, total leaf salinity-TLS) of sugar beets (cv. Rizor) grown unde...

Isotope discrimination is a common feature of biosynthesis in nature, with the result that different classes of carbon compounds frequently display different (13)C/(12)C ratios. The (13)C/(12)C ratio of lipid in potato tuber tissue is considerably lower than that for starch or protein. We have collected respiratory CO(2) from potato discs in successive periods through 24 hr from the time of cut...

The relative contributions of live Artemia metanauplii and an inert diet for growth of Senegalese sole larvae and postlarvae were assessed through the analysis of carbon stable isotopes ratios (δC) in both diets and whole larval tissue. Larvae were reared on four dietary regimes: 100% live prey (rotifers and Artemia), 100% inert formulated diet and two co-feeding regimes of 70:30 and 30:70 rati...