Revisiting the carbon isotope discrimination and water use efficiency relation: the influence of mesophyll conductance

Ting, Wei; Tcherkez, Guillaume; Wang, Xüming; Schaeufele, Rudi; Schnyder, H.; Yang, Yusheng; Gong, Xiaoping

doi:10.1101/2020.07.06.188920

Cited by 2 publications

(2 citation statements)

References 63 publications

(114 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A recent study by Ma et al . (2020) demonstrated that the ternary effect on iWUE Δ was small ( c . 1% error).…”

Section: Discussionmentioning

confidence: 99%

“…These factors are ternary effects and respiratory and photorespiratory fractionations. A recent study by Ma et al (2020) demonstrated that the ternary effect on iWUE Δ was small (c. 1% error). Our measurements for iWUE analyses occurred when light intensity was above 800 μmol mol −1 , and under these conditions the whole-tree 13 C-discrimination would have been largely dominated by photosynthesis (Drake et al, 2016).…”

Section: Whole-tree Mesophyll Conductance (G M )mentioning

confidence: 95%

See 1 more Smart Citation

Whole‐tree mesophyll conductance reconciles isotopic and gas‐exchange estimates of water‐use efficiency

et al. 2020

View full text Add to dashboard Cite

Summary Photosynthetic water‐use efficiency (WUE) describes the link between terrestrial carbon (C) and water cycles. Estimates of intrinsic WUE (iWUE) from gas exchange and C isotopic composition (δ13C) differ due to an internal conductance in the leaf mesophyll (gm) that is variable and seldom computed. We present the first direct estimates of whole‐tree gm, together with iWUE from whole‐tree gas exchange and δ13C of the phloem (δ13Cph). We measured gas exchange, online 13C‐discrimination, and δ13Cph monthly throughout spring, summer, and autumn in Eucalyptus tereticornis grown in large whole‐tree chambers. Six trees were grown at ambient temperatures and six at a 3°C warmer air temperature; a late‐summer drought was also imposed. Drought reduced whole‐tree gm. Warming had few direct effects, but amplified drought‐induced reductions in whole‐tree gm. Whole‐tree gm was similar to leaf gm for these same trees. iWUE estimates from δ13Cph agreed with iWUE from gas exchange, but only after incorporating gm. δ13Cph was also correlated with whole‐tree 13C‐discrimination, but offset by −2.5 ± 0.7‰, presumably due to post‐photosynthetic fractionations. We conclude that δ13Cph is a good proxy for whole‐tree iWUE, with the caveats that post‐photosynthetic fractionations and intrinsic variability of gm should be incorporated to provide reliable estimates of this trait in response to abiotic stress.

show abstract

“…A recent study by Ma et al . (2020) demonstrated that the ternary effect on iWUE Δ was small ( c . 1% error).…”

Section: Discussionmentioning

confidence: 99%

Section: Whole-tree Mesophyll Conductance (G M )mentioning

confidence: 95%

Whole‐tree mesophyll conductance reconciles isotopic and gas‐exchange estimates of water‐use efficiency

et al. 2020

View full text Add to dashboard Cite

show abstract

Differences in isotopic compositions of individual grains and aggregated seed samples affect interpretation of ancient plant cultivation practices

James,

Winter-Schuh,

Kenoyer

et al. 2024

Preprint

View full text Add to dashboard Cite

The stable carbon (lower case Greek delta13C) and nitrogen (lower case Greek delta15N) isotope analysis of charred archaeological grains provides a remarkably precise scale of information: the growing conditions under which a plant was cultivated in a single field and season. Here we investigate how the measurement of single individual grains or aggregate bulk samples for carbon and nitrogen isotopes impacts how we characterize variation and, consequently, our interpretations of ancient cultivation practices. Using experimentally grown barley (Hordeum vulgare var. nudum), this work investigates lower case Greek delta13C and lower case Greek delta15N intra-panicle variation between both uncharred and charred individual grains from four plants. We found limited intra- and inter-panicle isotopic variation in single grain isotope values, ca. 0.5per thousand in lower case Greek delta13C and ca. 1per thousand in lower case Greek delta15N, reemphasizing the degree to which grains are representative of their local growing conditions. To explore the interpretive impact of aggregate versus single-grain isotopic sampling, we measured charred barley recovered from a single storage context excavated from Trench 42 (ca. 1900 BCE) at Harappa. Aggregate samples of a random selection of Trench 42 barley demonstrated remarkable inter-sample homogeneity, with a less than 0.5per thousand difference in lower case Greek delta13C and lower case Greek delta15N values, reinforcing the ability of aggregate samples to capture a representative isotopic average of a single depositional context. However, the measurement of single-grains revealed moderate 2 to 3per thousand variation in lower case Greek delta13C, and an outstandingly wide isotopic variation of ca. 8per thousand in lower case Greek delta15N values, indicating the degree to which cultivation practices varied beyond what the bulk samples indicated. These results highlight how decisions in the selection and measurement of archaeological grains for isotopic analysis impact data resolution, with profound consequences for understanding past agricultural diversity.

show abstract

Revisiting the carbon isotope discrimination and water use efficiency relation: the influence of mesophyll conductance

Cited by 2 publications

References 63 publications

Whole‐tree mesophyll conductance reconciles isotopic and gas‐exchange estimates of water‐use efficiency

Whole‐tree mesophyll conductance reconciles isotopic and gas‐exchange estimates of water‐use efficiency

Differences in isotopic compositions of individual grains and aggregated seed samples affect interpretation of ancient plant cultivation practices

Contact Info

Product

Resources

About