A stomatal optimization theory to describe the effects of atmospheric CO2 on leaf photosynthesis and transpiration

Katul, Gabriel G.; Manzoni, Stefano; Palmroth, Sari; Oren, Ram

doi:10.1093/aob/mcp292

Cited by 317 publications

(377 citation statements)

References 68 publications

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“…Although several innovative studies have applied optimization theory to model plant gas exchange (Lloyd and Farquhar, 1994;Buckley, 2008;Katul et al, 2010;Medlyn et al, 2011;Bonan et al, 2014), it has not been as widely adopted as might have been expected from such an elegant theory. Stomatal control of leaf gas exchange was formulated in terms of optimization theory almost four decades ago (Cowan and Farquhar, 1977), but stomatal control has been modeled predominantly using semiempirical or hybrid mechanisticempirical approaches (Damour et al, 2010).…”

Section: Modeling Stomatal Conductance At All Scales Is Underpinned Bmentioning

confidence: 99%

“…An equation for g w can be obtained from this relationship with A expressed in terms of the Farquhar et al (1980b) photosynthesis model, but the form of the equation varies with the Rubisco and RuBP regeneration-limited rates of A (Arneth et al, 2002;Buckley et al, 2002;Katul et al, 2010;Medlyn et al, 2011;Vico et al, 2013;Buckley and Schymanski, 2014;Buckley et al, 2017). Although the utility of water-use efficiency optimization has been demonstrated in leaf gas-exchange studies, it has not been implemented directly in land surface models.…”

Section: Stomata In Global Models: Empirical and Optimization Approacmentioning

confidence: 99%

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Stomatal Function across Temporal and Spatial Scales: Deep-Time Trends, Land-Atmosphere Coupling and Global Models

et al. 2017

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Section: Modeling Stomatal Conductance At All Scales Is Underpinned Bmentioning

confidence: 99%

Section: Stomata In Global Models: Empirical and Optimization Approacmentioning

confidence: 99%

Stomatal Function across Temporal and Spatial Scales: Deep-Time Trends, Land-Atmosphere Coupling and Global Models

et al. 2017

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“…Stomatal conductance may be independently reduced in the future by higher water use efficiency under elevated CO 2 , with relative reductions on the order of about ∼20% predicted by both modelling and experimental work [17][18][19] . Here, we report relative reductions in G S driven by rising VPD on the order of 10% in most forest ecosystems, which would imply even greater relative reductions in canopy stomatal conductance since G S is influenced by soil conductance, which is not sensitive to VPD.…”

mentioning

confidence: 99%

“…Here, we report relative reductions in G S driven by rising VPD on the order of 10% in most forest ecosystems, which would imply even greater relative reductions in canopy stomatal conductance since G S is influenced by soil conductance, which is not sensitive to VPD. While VPD and CO 2 concentrations are assumed to be independent drivers of stomatal conductance in theoretical formulations 17,19 , the extent to which their effects on stomatal conductance are additive remains an important topic for future work, which must also consider the confounding effects of increasing leaf area index 29 .…”

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confidence: 99%

The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

et al. 2016

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Soil moisture supply and atmospheric demand for water independently limit-and profoundly a ect-vegetation productivity and water use during periods of hydrologic stress [1][2][3][4] . Disentangling the impact of these two drivers on ecosystem carbon and water cycling is di cult because they are often correlated, and experimental tools for manipulating atmospheric demand in the field are lacking. Consequently, the role of atmospheric demand is often not adequately factored into experiments or represented in models 5-7 . Here we show that atmospheric demand limits surface conductance and evapotranspiration to a greater extent than soil moisture in many biomes, including mesic forests that are of particular importance to the terrestrial carbon sink 8,9 . Further, using projections from ten general circulation models, we show that climate change will increase the importance of atmospheric constraints to carbon and water fluxes in all ecosystems. Consequently, atmospheric demand will become increasingly important for vegetation function, accounting for >70% of growing season limitation to surface conductance in mesic temperate forests. Our results suggest that failure to consider the limiting role of atmospheric demand in experimental designs, simulation models and land management strategies will lead to incorrect projections of ecosystem responses to future climate conditions. Ecosystem moisture stress is often characterized by changes in soil water availability 10,11 . Declining soil moisture impedes the movement of water to evaporating sites at the soil or leaf surface 12 , reducing the surface conductance to water vapour (G S )-a key determinant of carbon and water cycling-and thereby evapotranspiration (ET). However, atmospheric demand for water, which is directly related to the atmospheric vapour pressure deficit (VPD), also affects G S and ET. Plants close their stomata to prevent excessive water loss when VPD is high [13][14][15][16] and thus, increases in VPD during periods of hydrologic stress represent an independent constraint on plant carbon uptake and water use in ecosystems.While the plant physiological community has long recognized the critical role of VPD in determining plant functioning, VPD is often overlooked in many fields of hydrologic and climate science. For example, precipitation manipulation experiments are frequently used to draw conclusions about ecosystem response to drought stress, even though VPD is unaffected by precipitation manipulation 10 . Some terrestrial ecosystem and ecohydrological models do not permit stomatal conductance to vary with atmospheric demand 5,11 . Many models designed to capture these impacts rely on empirical parameterizations for soil moisture and VPD stress that promote compensating effects and model equifinality 5 , and/or use relative humidity instead of VPD as the primary driver, with significant consequences for projections of

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“…At shorter timescales, plants have the ability to adjust their phenotype to optimize gas exchange. In response to short (seconds to hours) perturbations in CO 2 , plants open and close their stomata (10,11), whereas in response to CO 2 changes at decadal to centennial timescales, plants adjust leaf stomatal density (D) and/or maximum stomatal dimensions (a max ) (12)(13)(14)(15). This process of epidermal structural adaptation is in part controlled by a signaling mechanism from mature to developing leaves, optimizing stomatal density and size to the changed environmental conditions (16).…”

mentioning

confidence: 99%

Global CO ₂ rise leads to reduced maximum stomatal conductance in Florida vegetation

Lammertsma

Boer

Dekker

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

226

149

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A principle response of C3 plants to increasing concentrations of atmospheric CO 2 (CO 2 ) is to reduce transpirational water loss by decreasing stomatal conductance (g s ) and simultaneously increase assimilation rates. Via this adaptation, vegetation has the ability to alter hydrology and climate. Therefore, it is important to determine the adaptation of vegetation to the expected anthropogenic rise in CO 2 . Short-term stomatal opening-closing responses of vegetation to increasing CO 2 are described by free-air carbon enrichments growth experiments, and evolutionary adaptations are known from the geological record. However, to date the effects of decadal to centennial CO 2 perturbations on stomatal conductance are still largely unknown. Here we reconstruct a 34% (±12%) reduction in maximum stomatal conductance (g smax ) per 100 ppm CO 2 increase as a result of the adaptation in stomatal density (D) and pore size at maximal stomatal opening (a max ) of nine common species from Florida over the past 150 y. The species-specific g smax values are determined by different evolutionary development, whereby the angiosperms sampled generally have numerous small stomata and high g smax , and the conifers and fern have few large stomata and lower g smax . Although angiosperms and conifers use different D and a max adaptation strategies, our data show a coherent response in g smax to CO 2 rise of the past century. Understanding these adaptations of C3 plants to rising CO 2 after decadal to centennial environmental changes is essential for quantification of plant physiological forcing at timescales relevant for global warming, and they are likely to continue until the limits of their phenotypic plasticity are reached. cuticular analysis | subtropical vegetation L and plants play a crucial role in regulating our planet's hydrological and energy balance by transpiring water through the stomatal pores on their leaf surfaces. A fundamental response of C3 plants to increasing atmospheric CO 2 concentration (CO 2 ) is to minimize transpirational water loss by reducing diffusive stomatal conductance (g s ) and simultaneously increasing assimilation rates (1). The resulting increased intrinsic water-use efficiency (iWUE: the ratio of assimilation to g s ) improves the vegetation's drought resistance and reduces the cost associated with the leaf's water transport system like leaf venation (2, 3). On a regional to global scale, decreasing rates of transpiration concurrently affect climate through reduced cloud formation and precipitation (4) and with this exert a physiological feedback on climate and hydrology on top of the radiative forcing of increasing CO 2 (5-7). In the light of continuing anthropogenic climate change, it is therefore imperative to determine how plants adapt to rising atmospheric CO 2 .During their 400 million year history, land plants have been exposed to large variations in environmental conditions that prompted genetic adaptations toward mechanisms that optimize individual fitness. Over this period, plant ad...

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A stomatal optimization theory to describe the effects of atmospheric CO2 on leaf photosynthesis and transpiration

Cited by 317 publications

References 68 publications

Stomatal Function across Temporal and Spatial Scales: Deep-Time Trends, Land-Atmosphere Coupling and Global Models

Stomatal Function across Temporal and Spatial Scales: Deep-Time Trends, Land-Atmosphere Coupling and Global Models

The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

Global CO ₂ rise leads to reduced maximum stomatal conductance in Florida vegetation

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A stomatal optimization theory to describe the effects of atmospheric CO2 on leaf photosynthesis and transpiration

Cited by 317 publications

References 68 publications

Stomatal Function across Temporal and Spatial Scales: Deep-Time Trends, Land-Atmosphere Coupling and Global Models

Stomatal Function across Temporal and Spatial Scales: Deep-Time Trends, Land-Atmosphere Coupling and Global Models

The increasing importance of atmospheric demand for ecosystem water and carbon fluxes

Global CO 2 rise leads to reduced maximum stomatal conductance in Florida vegetation

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Product

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Global CO ₂ rise leads to reduced maximum stomatal conductance in Florida vegetation