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Xylem hydraulic safety margins in woody plants: Coordination of stomatal control of xylem tension with hydraulic capacitance

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dc.contributor.author Meinzer, Frederick C. en
dc.contributor.author Johnson, Daniel M. en
dc.contributor.author Lachenbrunch, Barbara en
dc.contributor.author McCulloch, Katherine A. en
dc.contributor.author Woodruff, David R. en
dc.date.accessioned 2011-02-16T18:25:21Z
dc.date.available 2011-02-16T18:25:21Z
dc.date.issued 2009
dc.identifier.citation Meinzer, Frederick C., Johnson, Daniel M., Lachenbrunch, Barbara, McCulloch, Katherine A., and Woodruff, David R. 2009. "<a href="https%3A%2F%2Frepository.si.edu%2Fhandle%2F10088%2F12053">Xylem hydraulic safety margins in woody plants: Coordination of stomatal control of xylem tension with hydraulic capacitance</a>." <em>Functional Ecology</em>. 23 (4):922&ndash;930. <a href="https://doi.org/10.1111/j.1365-2435.2009.01577.x">https://doi.org/10.1111/j.1365-2435.2009.01577.x</a> en
dc.identifier.issn 0269-8463
dc.identifier.uri http://hdl.handle.net/10088/12053
dc.description.abstract 1. The xylem pressure inducing 50% loss of hydraulic conductivity due to embolism (P50) is widely used for comparisons of xylem vulnerability among species and across aridity gradients. However, despite its utility as an index of resistance to catastrophic xylem failure under extreme drought, P50 may have no special physiological relevance in the context of stomatal regulation of daily minimum xylem pressure and avoidance of hydraulic failure under non-extreme conditions. Moreover, few studies of hydraulic architecture have accounted for the buffering influence of tissue hydraulic capacitance on daily fluctuations in xylem pressure in intact plants. 2. We used data from 104 coniferous and angiosperm species representing a range of woody growth forms and habitat types to evaluate trends in three alternative xylem hydraulic safety margins based on features of their stem xylem vulnerability curves and regulation of daily minimum stem water potential (Wstem min) under non-extreme conditions: (i) Wstem min ) P50, (ii) Wstem min ) Pe, the difference between Wstem min and the threshold xylem pressure at which loss of conductivity begins to increase rapidly (Pe) and (iii) Pe ) P50, an estimate of the steepness of the vulnerability curve between Pe and P50. Additionally, we assessed relationships between xylem capacitance, species-specific set-points for daily minimum stem water potential and hydraulic safety margins in a subset of species for which relevant data were available. 3. The three types of hydraulic safety margin defined increased with decreasing species-specific set-points for Wstem min, suggesting a diminishing role of stem capacitance in slowing fluctuations in xylem pressure as Wstem min became more negative. The trends in hydraulic safety were similar among coniferous and angiosperm species native to diverse habitat types. 4. Our results suggest that here is a continuum of relative reliance on different mechanisms that confer hydraulic safety under dynamic conditions. Species with low capacitance and denser wood experience greater daily maximum xylem tension and appear to rely primarily on xylem structural features to avoid embolism, whereas in species with high capacitance and low wood density avoidance of embolism appears to be achieved primarily via reliance on transient release of stored water to constrain transpiration-induced fluctuations in xylem tension. en
dc.relation.ispartof Functional Ecology en
dc.title Xylem hydraulic safety margins in woody plants: Coordination of stomatal control of xylem tension with hydraulic capacitance en
dc.type Journal Article en
dc.identifier.srbnumber 90786
dc.identifier.doi 10.1111/j.1365-2435.2009.01577.x
rft.jtitle Functional Ecology
rft.volume 23
rft.issue 4
rft.spage 922
rft.epage 930
dc.description.SIUnit STRI en
dc.description.SIUnit Forces of Change en
dc.description.SIUnit Understanding and Sustaining a Biodiverse Planet en
dc.description.SIUnit Canopy Crane Access System en
dc.citation.spage 922
dc.citation.epage 930

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