The Intra-Annual Intrinsic Water Use Efficiency Dynamics Based on an Improved Model

Abstract The carbon isotope fractionation value (Δ) has been widely used to infer the intrinsic water use efficiency (iWUE) of C3 plants. Currently, the most commonly used iWUE method (expressed as iWUE tra ) in tree rings assumes that the mesophyll conductance in plants is infinite. However, many observation-based studies have pointed out that such an assumption leads to overestimating the impact of carbon dioxide (CO 2 ) on intrinsic water use efficiency in plants. In this study, a constant g s /g m ratio (0.79) was introduced for calculating iWUE (expressedas iWUE mes ). We applied this iWUE mes model to our newly developed intra-annual (10 samples per ring) Δ 13 C chronology of Cryptomeria fortunei tree for 1965–2017 at Gu Mountain Area and our annual Δ 13 C chronology of Pinus massoniana tree for 1865–2014 at Niumulin Natural Reserve in southeast China. Using dendrochronology techniques, our analysis revealed that the current iWUE tra model overestimates the iWUE values by approximately 2 times and that the iWUE value of trees inferred from iWUE mes modelling decreased significantly in summer-autumn time, which may indicate that alternative factors play a role in limiting the degree of iWUE improvement under the drought-stressed forest in southeast China.

Download Full-text

Growth decline of Pinus Massoniana in response to warming induced drought and increasing intrinsic water use efficiency in humid subtropical China

Dendrochronologia ◽

10.1016/j.dendro.2019.125609 ◽

2019 ◽

Vol 57 ◽

pp. 125609 ◽

Cited By ~ 2

Author(s):

Yingjun Li ◽

Zhipeng Dong ◽

Deliang Chen ◽

Siyuan Zhao ◽

Feifei Zhou ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Pinus Massoniana ◽

Subtropical China ◽

Intrinsic Water Use Efficiency ◽

Growth Decline ◽

Use Efficiency

Download Full-text

Drought-induced mortality selectively affects Scots pine trees that show limited intrinsic water-use efficiency responsiveness to raising atmospheric CO2

Functional Plant Biology ◽

10.1071/fp13067 ◽

2014 ◽

Vol 41 (3) ◽

pp. 244 ◽

Cited By ~ 24

Author(s):

Ana-Maria Hereş ◽

Jordi Voltas ◽

Bernat Claramunt López ◽

Jordi Martínez-Vilalta

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Tree Mortality ◽

Intercellular Co2 Concentration ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Growth Enhancement ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency ◽

The Impact

Widespread drought-induced tree mortality has been documented around the world, and could increase in frequency and intensity under warmer and drier conditions. Ecophysiological differences between dying and surviving trees might underlie predispositions to mortality, but are poorly documented. Here we report a study of Scots pines (Pinus sylvestris L.) from two sites located in north-eastern Iberian Peninsula where drought-associated mortality episodes were registered during the last few decades. Time trends of discrimination against 13C (Δ13C) and intrinsic water-use efficiency (WUEi) in tree rings at an annual resolution and for a 34 year period were used to compare co-occurring now-dead and surviving pines. Results indicate that both surviving and now-dead pines significantly increased their WUEi over time, although this increase was significantly lower for now-dead individuals. These differential WUEi trends corresponded to different scenarios describing how plant gas exchange responds to increasing atmospheric CO2 (Ca): the estimated intercellular CO2 concentration was nearly constant in surviving pines but tended to increase proportionally to Ca in now-dead trees. Concurrently, the WUEi increase was not paralleled by a growth enhancement, regardless of tree state, suggesting that in water-limited areas like the Mediterranean, it cannot overcome the impact of an increasingly warmer and drier climate on tree growth.

Download Full-text

Mesophyll conductance to CO2 and Rubisco as targets for improving intrinsic water use efficiency in C3 plants

Plant Cell & Environment ◽

10.1111/pce.12622 ◽

2015 ◽

Vol 39 (5) ◽

pp. 965-982 ◽

Cited By ~ 94

Author(s):

J. Flexas ◽

A. Díaz-Espejo ◽

M. A. Conesa ◽

R. E. Coopman ◽

C. Douthe ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

C3 Plants ◽

Mesophyll Conductance ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency

Download Full-text

Directional change in leaf dry matter δ 13C during leaf development is widespread in C3 plants

Annals of Botany ◽

10.1093/aob/mcaa114 ◽

2020 ◽

Vol 126 (6) ◽

pp. 981-990

Author(s):

Nara O Vogado ◽

Klaus Winter ◽

Nerea Ubierna ◽

Graham D Farquhar ◽

Lucas A Cernusak

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Developmental Change ◽

Leaf Expansion ◽

C3 Plants ◽

Evergreen Species ◽

Mature Leaves ◽

Intrinsic Water Use Efficiency ◽

Young Leaves ◽

Use Efficiency

Abstract Background and aims The stable carbon isotope ratio of leaf dry matter (δ 13Cp) is generally a reliable recorder of intrinsic water-use efficiency in C3 plants. Here, we investigated a previously reported pattern of developmental change in leaf δ 13Cp during leaf expansion, whereby emerging leaves are initially 13C-enriched compared to mature leaves on the same plant, with their δ 13Cp decreasing during leaf expansion until they eventually take on the δ 13Cp of other mature leaves. Methods We compiled data to test whether the difference between mature and young leaf δ 13Cp differs between temperate and tropical species, or between deciduous and evergreen species. We also tested whether the developmental change in δ 13Cp is indicative of a concomitant change in intrinsic water-use efficiency. To gain further insight, we made online measurements of 13C discrimination (∆ 13C) in young and mature leaves. Key Results We found that the δ 13Cp difference between mature and young leaves was significantly larger for deciduous than for evergreen species (−2.1 ‰ vs. −1.4 ‰, respectively). Counter to expectation based on the change in δ 13Cp, intrinsic water-use efficiency did not decrease between young and mature leaves; rather, it did the opposite. The ratio of intercellular to ambient CO2 concentrations (ci/ca) was significantly higher in young than in mature leaves (0.86 vs. 0.72, respectively), corresponding to lower intrinsic water-use efficiency. Accordingly, instantaneous ∆ 13C was also higher in young than in mature leaves. Elevated ci/ca and ∆ 13C in young leaves resulted from a combination of low photosynthetic capacity and high day respiration rates. Conclusion The decline in leaf δ 13Cp during leaf expansion appears to reflect the addition of the expanding leaf’s own 13C-depleted photosynthetic carbon to that imported from outside the leaf as the leaf develops. This mixing of carbon sources results in an unusual case of isotopic deception: less negative δ 13Cp in young leaves belies their low intrinsic water-use efficiency.

Download Full-text

Genetic improvement of leaf photosynthesis and intrinsic water use efficiency in C3 plants: Why so much little success?

Plant Science ◽

10.1016/j.plantsci.2016.05.002 ◽

2016 ◽

Vol 251 ◽

pp. 155-161 ◽

Cited By ~ 41

Author(s):

J. Flexas

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Genetic Improvement ◽

C3 Plants ◽

Leaf Photosynthesis ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency

Download Full-text

Rising CO2 drives divergence in water use efficiency of evergreen and deciduous plants

Science Advances ◽

10.1126/sciadv.aax7906 ◽

2019 ◽

Vol 5 (12) ◽

pp. eaax7906 ◽

Cited By ~ 7

Author(s):

Wuu Kuang Soh ◽

Charilaos Yiotis ◽

Michelle Murray ◽

Andrew Parnell ◽

Ian J. Wright ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Boreal Forests ◽

Leaf Mass Per Area ◽

Mean Annual Temperature ◽

Evergreen Species ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency ◽

The Difference ◽

The Impact

Intrinsic water use efficiency (iWUE), defined as the ratio of photosynthesis to stomatal conductance, is a key variable in plant physiology and ecology. Yet, how rising atmospheric CO2 concentration affects iWUE at broad species and ecosystem scales is poorly understood. In a field-based study of 244 woody angiosperm species across eight biomes over the past 25 years of increasing atmospheric CO2 (~45 ppm), we show that iWUE in evergreen species has increased more rapidly than in deciduous species. Specifically, the difference in iWUE gain between evergreen and deciduous taxa diverges along a mean annual temperature gradient from tropical to boreal forests and follows similar observed trends in leaf functional traits such as leaf mass per area. Synthesis of multiple lines of evidence supports our findings. This study provides timely insights into the impact of Anthropocene climate change on forest ecosystems and will aid the development of next-generation trait-based vegetation models.

Download Full-text

The impact of stomatal kinetics on diurnal photosynthesis and water use efficiency under fluctuating light

10.1101/2020.09.03.281873 ◽

2020 ◽

Author(s):

David Eyland ◽

Jelle van Wesemael ◽

Tracy Lawson ◽

Sebastien Carpentier

Keyword(s):

Light Intensity ◽

Water Use Efficiency ◽

Water Use ◽

Light Conditions ◽

Fluctuating Light ◽

Whole Plant ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency ◽

Plant Level ◽

The Impact

AbstractDynamic light conditions require continuous adjustments of stomatal aperture. As stomatal conductance (gs) kinetics are a magnitude slower than photosynthesis (A), they are hypothesized to be key to plant productivity and water use efficiency. Using step-changes in light intensity, we studied the diversity of light-induced gs kinetics in relation to stomatal anatomy in five banana genotypes (Musa spp.) and modelled the impact on A and intrinsic water use efficiency (iWUE). Banana generally exhibited a strong limitation of A by gs, indicating a priority for water saving. Significant genotypic differences in gs kinetics and gs-based limitations of A were observed. For two contrasting genotypes the impact of differential gs kinetics on A and iWUE was further investigated under realistic diurnally fluctuating light conditions and at whole-plant level. Genotype-specific stomatal kinetics observed at the leaf level were corroborated at whole-plant level, suggesting that despite differences in gs control at different locations in the leaf and across leaves, genotype-specific responses are still maintained. However, under diurnally fluctuating light conditions gs speediness had only a momentary impact on the diurnal iWUE and carbon gain. During the afternoon there was a setback in kinetics: the absolute gs and the gs responses to light were damped, strongly limiting A and the diurnal iWUE. We conclude that the impact of the differential gs kinetics on the limitation of A was dependent on the target light intensity, the magnitude of change, the gs prior to the intensity change and particularly the time of the day.One sentence summaryGenotype-specific stomatal rapidity is for the first time validated at whole-plant level, but under fluctuating light the impact of stomatal dynamics depends on other factors like the time of the day.

Download Full-text