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Article: The response of stomatal conductance to seasonal drought in tropical forests

TitleThe response of stomatal conductance to seasonal drought in tropical forests
Authors
Keywordscarbon and water exchange
leaf age
leaf water potential
plant traits
spectroscopy
Issue Date2020
PublisherWiley-Blackwell Publishing Ltd. The Journal's web site is located at http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-2486
Citation
Global Change Biology, 2020, v. 26 n. 2, p. 823-839 How to Cite?
AbstractStomata regulate CO2 uptake for photosynthesis and water loss through transpiration. The approaches used to represent stomatal conductance (gs) in models vary. In particular, current understanding of drivers of the variation in a key parameter in those models, the slope parameter (i.e. a measure of intrinsic plant water‐use‐efficiency), is still limited, particularly in the tropics. Here we collected diurnal measurements of leaf gas exchange and leaf water potential (Ψleaf), and a suite of plant traits from the upper canopy of 15 tropical trees in two contrasting Panamanian forests throughout the dry season of the 2016 El Niño. The plant traits included wood density, leaf‐mass‐per‐area (LMA), leaf carboxylation capacity (Vc,max), leaf water content, the degree of isohydry, and predawn Ψleaf. We first investigated how the choice of four commonly used leaf‐level gs models with and without the inclusion of Ψleaf as an additional predictor variable influence the ability to predict gs, and then explored the abiotic (i.e. month, site‐month interaction) and biotic (i.e. tree‐species‐specific characteristics) drivers of slope parameter variation. Our results show that the inclusion of Ψleaf did not improve model performance and that the models that represent the response of gs to vapor pressure deficit performed better than corresponding models that respond to relative humidity. Within each gs model, we found large variation in the slope parameter, and this variation was attributable to the biotic driver, rather than abiotic drivers. We further investigated potential relationships between the slope parameter and the six available plant traits mentioned above, and found that only one trait, LMA, had a significant correlation with the slope parameter (R2 = 0.66, n = 15), highlighting a potential path towards improved model parameterization. This study advances understanding of gs dynamics over seasonal drought, and identifies a practical, trait‐based approach to improve modeling of carbon and water exchange in tropical forests.
Persistent Identifierhttp://hdl.handle.net/10722/280331
ISSN
2019 Impact Factor: 8.555
2015 SCImago Journal Rankings: 5.379

 

DC FieldValueLanguage
dc.contributor.authorWu, J-
dc.contributor.authorSerbin, SP-
dc.contributor.authorEly, KS-
dc.contributor.authorWolfe, BT-
dc.contributor.authorDickman, LT-
dc.contributor.authorGrossiord, C-
dc.contributor.authorMichaletz, ST-
dc.contributor.authorCollins, AD-
dc.contributor.authorDetto, M-
dc.contributor.authorMcDowell, NG-
dc.contributor.authorWright, SJ-
dc.contributor.authorRogers, A-
dc.date.accessioned2020-02-07T07:39:36Z-
dc.date.available2020-02-07T07:39:36Z-
dc.date.issued2020-
dc.identifier.citationGlobal Change Biology, 2020, v. 26 n. 2, p. 823-839-
dc.identifier.issn1354-1013-
dc.identifier.urihttp://hdl.handle.net/10722/280331-
dc.description.abstractStomata regulate CO2 uptake for photosynthesis and water loss through transpiration. The approaches used to represent stomatal conductance (gs) in models vary. In particular, current understanding of drivers of the variation in a key parameter in those models, the slope parameter (i.e. a measure of intrinsic plant water‐use‐efficiency), is still limited, particularly in the tropics. Here we collected diurnal measurements of leaf gas exchange and leaf water potential (Ψleaf), and a suite of plant traits from the upper canopy of 15 tropical trees in two contrasting Panamanian forests throughout the dry season of the 2016 El Niño. The plant traits included wood density, leaf‐mass‐per‐area (LMA), leaf carboxylation capacity (Vc,max), leaf water content, the degree of isohydry, and predawn Ψleaf. We first investigated how the choice of four commonly used leaf‐level gs models with and without the inclusion of Ψleaf as an additional predictor variable influence the ability to predict gs, and then explored the abiotic (i.e. month, site‐month interaction) and biotic (i.e. tree‐species‐specific characteristics) drivers of slope parameter variation. Our results show that the inclusion of Ψleaf did not improve model performance and that the models that represent the response of gs to vapor pressure deficit performed better than corresponding models that respond to relative humidity. Within each gs model, we found large variation in the slope parameter, and this variation was attributable to the biotic driver, rather than abiotic drivers. We further investigated potential relationships between the slope parameter and the six available plant traits mentioned above, and found that only one trait, LMA, had a significant correlation with the slope parameter (R2 = 0.66, n = 15), highlighting a potential path towards improved model parameterization. This study advances understanding of gs dynamics over seasonal drought, and identifies a practical, trait‐based approach to improve modeling of carbon and water exchange in tropical forests.-
dc.languageeng-
dc.publisherWiley-Blackwell Publishing Ltd. The Journal's web site is located at http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-2486-
dc.relation.ispartofGlobal Change Biology-
dc.rightsPreprint This is the pre-peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Postprint This is the peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.-
dc.subjectcarbon and water exchange-
dc.subjectleaf age-
dc.subjectleaf water potential-
dc.subjectplant traits-
dc.subjectspectroscopy-
dc.titleThe response of stomatal conductance to seasonal drought in tropical forests-
dc.typeArticle-
dc.identifier.emailWu, J: jinwu@hku.hk-
dc.identifier.authorityWu, J=rp02509-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1111/gcb.14820-
dc.identifier.pmid31482618-
dc.identifier.scopuseid_2-s2.0-85074111056-
dc.identifier.hkuros309065-
dc.identifier.volume26-
dc.identifier.issue2-
dc.identifier.spage823-
dc.identifier.epage839-
dc.publisher.placeUnited Kingdom-

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