Separating Active and Passive Influences on Stomatal Control of Transpiration

McAdam, Scott A. M.; Brodribb, Timothy J.

doi:10.1104/pp.113.231944

Cited by 134 publications

(133 citation statements)

References 45 publications

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“…Additionally, when compared on the basis of relative hysteresis, when sap flux has been normalized by the maximal sap flux for that day, red maples in both plots demonstrated lower relative hysteresis than shown by red oaks. White pine, the only coniferous species in this study, consistently had the least amount of diurnal hysteresis, which is consistent with the results of McAdam and Brodribb [2014] and for other conifers. These different responses to soil water availability and canopy light penetration discussed above support the first half of our second hypothesis, that disturbance-related changes to external physical drivers of transpiration would influence the diurnal pattern of transpiration more strongly in some species than others.…”

Section: Red Oaksupporting

confidence: 80%

Species‐specific transpiration responses to intermediate disturbance in a northern hardwood forest

et al. 2014

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Intermediate disturbances shape forest structure and composition, which may in turn alter carbon, nitrogen, and water cycling. We used a large-scale experiment in a forest in northern lower Michigan where we prescribed an intermediate disturbance by stem girdling all canopy-dominant early successional trees to simulate an accelerated age-related senescence associated with natural succession. Using 3 years of eddy covariance and sap flux measurements in the disturbed area and an adjacent control plot, we analyzed disturbance-induced changes to plot level and species-specific transpiration and stomatal conductance. We found transpiration to be~15% lower in disturbed plots than in unmanipulated control plots. However, species-specific responses to changes in microclimate varied. While red oak and white pine showed increases in stomatal conductance during postdisturbance (62.5 and 132.2%, respectively), red maple reduced stomatal conductance by 36.8%. We used the hysteresis between sap flux and vapor pressure deficit to quantify diurnal hydraulic stress incurred by each species in both plots. Red oak, a ring porous anisohydric species, demonstrated the largest mean relative hysteresis, while red maple, bigtooth aspen, and paper birch, all diffuse porous species, had the lowest relative hysteresis. We employed the Penman-Monteith model for LE to demonstrate that these species-specific responses to disturbance are not well captured using current modeling strategies and that accounting for changes to leaf area index and plot microclimate are insufficient to fully describe the effects of disturbance on transpiration.

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Section: Red Oaksupporting

confidence: 80%

Species‐specific transpiration responses to intermediate disturbance in a northern hardwood forest

et al. 2014

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“…3, To regulate diurnal leaf gas exchange, foliar ABA levels must change over a timeframe that is relevant to the stomatal response to changes in VPD. Data for the gymnosperm Metasequoia glyptostroboides, taken from McAdam and Brodribb (2014), show strong increases in ABA level in branches that are dehydrated and maintained at specific leaf water potentials for a minimum of 6 h. This contrasts with data from the angiosperm species Pisum sativum taken from , which like most angiosperms displays a strong increase in ABA level after only 20 min following a doubling in vapor pressure deficit from 0.7 to 1.5 kPa. Bottom, Mapping these key transitions to a phylogeny of land plants, which assumes that mosses are sister to liverworts (Wickett et al, 2014) and divergent from hornworts, shows that only in angiosperms do all three of these essential physiological and molecular requirements for diurnal gas exchange control by ABA occur.…”

Section: Diversity In the Regulation Of Water Use Among Seed Plants Icontrasting

confidence: 47%

Evolution of the Stomatal Regulation of Plant Water Content

2017

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“…On the other hand, conifer leaves have been reported to be quite vulnerable to declines in K leaf (the water potential causes 50% loss of K leaf , ranging from 20.8 to 21.65 MPa) and have been assumed to undergo diurnal cavitation and repair (Woodruff et al, 2007(Woodruff et al, , 2008Domec et al, 2009;Johnson et al, 2009aJohnson et al, , 2009bJohnson et al, , 2011McCulloh et al, 2014; but see Brodribb and Cochard, 2009;McAdam and Brodribb, 2014). This pattern results in a puzzle that, if stem xylem of conifers is highly resistant to cavitation, what is the adaptive value of highly vulnerable leaves that require potentially metabolically expensive diurnal repair?…”

Section: Discussionmentioning

confidence: 99%

Reversible Deformation of Transfusion Tracheids in Taxus baccata Is Associated with a Reversible Decrease in Leaf Hydraulic Conductance

et al. 2014

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Declines in leaf hydraulic conductance (K leaf ) with increasing water stress have been attributed to cavitation of the leaf xylem. However, in the leaves of conifers, the reversible collapse of transfusion tracheids may provide an alternative explanation. Using Taxus baccata, a conifer species without resin, we developed a modified rehydration technique that allows the separation of declines in K leaf into two components: one reversible and one irreversible upon relaxation of water potential to 21 MPa. We surveyed leaves at a range of water potentials for evidence of cavitation using cryo-scanning electron microscopy and quantified dehydration-induced structural changes in transfusion tracheids by cryo-fluorescence microscopy. Irreversible declines in K leaf did not occur until leaf water potentials were more negative than 23 MPa. Declines in K leaf between 22 and 23 MPa were reversible and accompanied by the collapse of transfusion tracheids, as evidenced by cryo-fluorescence microscopy. Based on cryo-scanning electron microscopy, cavitation of either transfusion or xylem tracheids did not contribute to declines in K leaf in the reversible range. Moreover, the deformation of transfusion tracheids was quickly reversible, thus acting as a circuit breaker regulating the flux of water through the leaf vasculature. As transfusion tissue is present in all gymnosperms, the reversible collapse of transfusion tracheids may be a general mechanism in this group for the protection of leaf xylem from excessive loads generated in the living leaf tissue.

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Separating Active and Passive Influences on Stomatal Control of Transpiration

Cited by 134 publications

References 45 publications

Species‐specific transpiration responses to intermediate disturbance in a northern hardwood forest

Species‐specific transpiration responses to intermediate disturbance in a northern hardwood forest

Evolution of the Stomatal Regulation of Plant Water Content

Reversible Deformation of Transfusion Tracheids in Taxus baccata Is Associated with a Reversible Decrease in Leaf Hydraulic Conductance

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