The influence of predawn leaf water potential on stomatal responses to atmospheric water content at constant Ci and on stem hydraulic conductance and foliar ABA concentrations

Thomas, Damon

doi:10.1093/jexbot/50.331.243

Cited by 50 publications

(59 citation statements)

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“…Stomatal behaviour became more and more regulatory as leaf water potential declined. Consequently, at the most severe levels of stress modeled, for almost the whole range of increasing D, E declined, as has been observed previously [5,6,37]. Thus the entire stomatal response to increasing D, for the entire range of D, became confined to the lowest part of the response curve whereby E was reduced at all values of D. Therefore we can conclude that as stress developed, stomata regulated transpiration at ever decreasing values of D – that is, stomatal sensitivity to D increased with increasing levels of water stress.…”

Section: Discussionsupporting

confidence: 80%

“…However, the mechanism by which changes in D result in changes in Gs, remain debated. There is considerable evidence that Gs responds to transpiration rate (E) rather than D per se [11,12,5], although some argue that transpiration rate is not responsible [13], but acts merely as the carrier for the primary messenger, such as abscisic acid or xylem pH or both [1]. …”

Section: Introductionmentioning

confidence: 99%

“…There is increasing evidence to support the view that there are three phases to the stomatal response to E [5,12,25]. Initially, at low values of D, as D increases, Gs is high and E increases (phase C of [12]).…”

Section: Introductionmentioning

confidence: 99%

“…Water stress reduces maximum Gs [5,6,8,26]. However, water stress also influences the response of stomata to D and E [6,27].…”

Section: Introductionmentioning

confidence: 99%

“…However, water stress also influences the response of stomata to D and E [6,27]. In particular, as water stress develops, stomatal sensitivity to D increases and so-called feed forward responses dominate such that E is reduced for all values of D [5]. …”

Section: Introductionmentioning

confidence: 99%

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Eamus

Shanahan

2002

BMC Ecol

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BackgroundStomata respond to vapour pressure deficit (D) – when D increases, stomata begin to close. Closure is the result of a decline in guard cell turgor, but the link between D and turgor is poorly understood. We describe a model for stomatal responses to increasing D based upon cellular water relations. The model also incorporates impacts of increasing levels of water stress upon stomatal responses to increasing D.ResultsThe model successfully mimics the three phases of stomatal responses to D and also reproduces the impact of increasing plant water deficit upon stomatal responses to increasing D. As water stress developed, stomata regulated transpiration at ever decreasing values of D. Thus, stomatal sensitivity to D increased with increasing water stress. Predictions from the model concerning the impact of changes in cuticular transpiration upon stomatal responses to increasing D are shown to conform to experimental data.Sensitivity analyses of stomatal responses to various parameters of the model show that leaf thickness, the fraction of leaf volume that is air-space, and the fraction of mesophyll cell wall in contact with air have little impact upon behaviour of the model. In contrast, changes in cuticular conductance and membrane hydraulic conductivity have significant impacts upon model behaviour.ConclusionCuticular transpiration is an important feature of stomatal responses to D and is the cause of the 3 phase response to D. Feed-forward behaviour of stomata does not explain stomatal responses to D as feedback, involving water loss from guard cells, can explain these responses.

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Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Water stress reduces maximum Gs [5,6,8,26]. However, water stress also influences the response of stomata to D and E [6,27].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Eamus

Shanahan

2002

BMC Ecol

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Transpiration from a Cryptomeria japonica plantation, part 1: aerodynamic control of transpiration

Komatsu

Kang

Kume

et al. 2006

Hydrological Processes

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Abstract:To our knowledge, no one has examined the canopy conductance of a Cryptomeria japonica plantation, although such forests are very common in Japan. We plan to examine the canopy conductance of a Cryptomeria japonica plantation (canopy height 8 m) based on 1-year sap-flow data using the simplified Penman-Monteith equation. This study examines the effect of the aerodynamic control of transpiration before calculating canopy conductance using the simplified Penman-Monteith equation, because the equation assumes that the effect of aerodynamic control is negligible. To examine the effect of aerodynamic control, we examined the dependency of the relationship between the vapour pressure deficit (VPD) and transpiration on wind speed, when solar radiation, air temperature, and soil water content do not limit transpiration greatly. The relationship between VPD and the heat pulse velocity measured 11 m above the ground was dependent on wind speed only when the wind speed was <0Ð7 m s 1 . This suggests that the effect of aerodynamic control was negligible when the wind speed was ½0Ð7 m s 1 , but that the effect was not negligible when the wind speed was <0Ð7 m s 1 . Therefore, we should use data from when the wind speed was ½0Ð7 m s 1 for calculating canopy conductance G c , based on the simplified Penman-Monteith equation. Although this criterion is site specific, the methods used to develop it are applicable to other sites.

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Change of water vapor exchange properties of 3 tree species under drought

Chen

2002

Journal of Arid Environments

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The influence of predawn leaf water potential on stomatal responses to atmospheric water content at constant Ci and on stem hydraulic conductance and foliar ABA concentrations

Cited by 50 publications

References 0 publications

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Transpiration from a Cryptomeria japonica plantation, part 1: aerodynamic control of transpiration

Change of water vapor exchange properties of 3 tree species under drought

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