Regulation of branch-level gas exchange of boreal trees: roles of shoot water potential and vapor pressure difference

Regulation of branch-level gas exchange of boreal trees: roles of shoot water potential and vapor... Effects of shoot water potential (Ψ) and leaf-to-atmosphere vapor pressure difference (VPD) on gas exchange of jack pine ( Pinus banksiana Lamb.), black spruce ( Picea mariana (Mill.) B.S.P.), and aspen ( Populus tremuloides Michx.) were investigated at the northern edge of the boreal forest in Manitoba, Canada. Laboratory measurements on cut branches showed that net photosynthesis ( A n ) and mesophyll conductance ( g m ) of jack pine and g m of black spruce did not respond to Ψ until a threshold Ψ was reached below which they decreased linearly. Photosynthesis of black spruce decreased slowly with decreasing Ψ above the threshold and declined more rapidly thereafter. The threshold Ψ was lower in black spruce than in jack pine. However, stomatal conductance ( g s ) of black spruce decreased continuously with decreasing Ψ, whereas g s of jack pine showed a threshold response. Mesophyll limitations were primarily responsible for the decline in A n at low Ψ for jack pine and black spruce in the middle of the growing season, but stomatal limitations became more important later in the season. Field measurements on in situ branches on warm sunny days showed that both conifer species maintained Ψ above the corresponding threshold and there was no evidence of Ψ limitation on A n of jack pine, black spruce or aspen. Vapor pressure difference was important in regulating gas exchange in all three species. An empirical model was used to quantify the g s response to VPD. When parameterized with laboratory data for the conifers, the model also fit the corresponding field data. When parameterized with field data, the model showed that stomata of aspen were the most sensitive of the three species to VPD, and stomata of black spruce were the least sensitive. For jack pine and aspen, stomata of foliage in the upper canopy were significantly more sensitive than stomata of foliage in the lower canopy. Vapor pressure difference had a greater impact on A n of aspen than on A n of the conifers as a result of aspen's greater stomatal sensitivity to VPD and greater slope of the relationship between A n and intercellular CO 2 concentration ( C i ). During the 1994 growing season, VPD averaged 1.0 kPa, corresponding to ratios of C i to ambient CO 2 of 0.77, 0.71 and 0.81 for jack pine, black spruce and aspen, respectively. We conclude that increases in VPD at the leaf surface in response to climate change should affect the absolute CO 2 and H 2 O fluxes per unit leaf area of the aspen component of a boreal forest landscape more than those of the conifer component. Key words aspen black spruce jack pine photosynthesis stomatal conductance © 1997 Heron Publishing—Victoria Canada « Previous | Next Article » Table of Contents This Article Tree Physiol (1997) 17 (8-9): 521-535. doi: 10.1093/treephys/17.8-9.521 » Abstract Free Full Text (PDF) Free Classifications Original Article Services Article metrics Alert me when cited Alert me if corrected Find similar articles Similar articles in Web of Science Similar articles in PubMed Add to my archive Download citation Request Permissions Citing Articles Load citing article information Citing articles via CrossRef Citing articles via Scopus Citing articles via Web of Science Citing articles via Google Scholar Google Scholar Articles by Dang, Q. L. Articles by Collatz, G. J. Search for related content PubMed PubMed citation Articles by Dang, Q. L. Articles by Margolis, H. A. Articles by Coyea, M. R. Articles by Sy, M. Articles by Collatz, G. J. Related Content Load related web page information Share Email this article CiteULike Delicious Facebook Google+ Mendeley Twitter What's this? Search this journal: Advanced » Current Issue November 2015 35 (11) Alert me to new issues The Journal About this journal Rights & permissions We are mobile – find out more This journal is a member of the Committee on Publication Ethics (COPE) Journals Career Network Impact factor: 3.655 5-Yr impact factor: 3.787 Ram Oren, Editor-in-Chief Torgny Näsholm, Associate Editor-In-Chief Sari Palmroth, Managing Editor View the full editorial board For Authors Instructions to authors Services for authors Online submission instructions Submit Now! Author Self Archiving Policy Open access options available for authors - visit Oxford Open Corporate Services What we offer Advertising sales Reprints Supplements Alerting Services Email table of contents XML RSS feed var taxonomies = ("SCI01210"); Most Most Read Nutrition of mangroves Relationships of tree height and diameter at breast height revisited: analyses of stem growth using 20-year data of an even-aged Chamaecyparis obtusa stand A method for routine measurements of total sugar and starch content in woody plant tissues Non-structural carbohydrates in woody plants compared among laboratories Size, shape and surface morphology of starch granules from Norway spruce needles revealed by transmission electron microscopy and atomic force microscopy: effects of elevated CO2 concentration » View all Most Read articles Most Cited Scaling of angiosperm xylem structure with safety and efficiency Evaluation of transpiration in a Douglas-fir stand by means of sap flow measurements A mathematical and statistical analysis of the curves illustrating vulnerability of xylem to cavitation Carbon dynamics in trees: feast or famine? 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Online ISSN 1758-4469 - Print ISSN 0829-318X Copyright © 2015 Oxford University Press Oxford Journals Oxford University Press Site Map Privacy Policy Cookie Policy Legal Notices Frequently Asked Questions Other Oxford University Press sites: Oxford University Press Oxford Journals China Oxford Journals Japan Academic & Professional books Children's & Schools Books Dictionaries & Reference Dictionary of National Biography Digital Reference English Language Teaching Higher Education Textbooks International Education Unit Law Medicine Music Online Products & Publishing Oxford Bibliographies Online Oxford Dictionaries Online Oxford English Dictionary Oxford Language Dictionaries Online Oxford Scholarship Online Reference Rights and Permissions Resources for Retailers & Wholesalers Resources for the Healthcare Industry Very Short Introductions World's Classics function fnc_onDomLoaded() { var query_context = getQueryContext(); PF_initOIUnderbar(query_context,":QS:default","","JRN"); PF_insertOIUnderbar(0); }; if (window.addEventListener) { window.addEventListener('load', fnc_onDomLoaded, false); } else if (window.attachEvent) { window.attachEvent('onload', fnc_onDomLoaded); } var gaJsHost = (("https:" == document.location.protocol) ? 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Regulation of branch-level gas exchange of boreal trees: roles of shoot water potential and vapor pressure difference

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Publisher
Oxford University Press
Copyright
Copyright © 2015 Oxford University Press
ISSN
0829-318X
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1758-4469
D.O.I.
10.1093/treephys/17.8-9.521
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Abstract

Effects of shoot water potential (Ψ) and leaf-to-atmosphere vapor pressure difference (VPD) on gas exchange of jack pine ( Pinus banksiana Lamb.), black spruce ( Picea mariana (Mill.) B.S.P.), and aspen ( Populus tremuloides Michx.) were investigated at the northern edge of the boreal forest in Manitoba, Canada. Laboratory measurements on cut branches showed that net photosynthesis ( A n ) and mesophyll conductance ( g m ) of jack pine and g m of black spruce did not respond to Ψ until a threshold Ψ was reached below which they decreased linearly. Photosynthesis of black spruce decreased slowly with decreasing Ψ above the threshold and declined more rapidly thereafter. The threshold Ψ was lower in black spruce than in jack pine. However, stomatal conductance ( g s ) of black spruce decreased continuously with decreasing Ψ, whereas g s of jack pine showed a threshold response. Mesophyll limitations were primarily responsible for the decline in A n at low Ψ for jack pine and black spruce in the middle of the growing season, but stomatal limitations became more important later in the season. Field measurements on in situ branches on warm sunny days showed that both conifer species maintained Ψ above the corresponding threshold and there was no evidence of Ψ limitation on A n of jack pine, black spruce or aspen. Vapor pressure difference was important in regulating gas exchange in all three species. An empirical model was used to quantify the g s response to VPD. When parameterized with laboratory data for the conifers, the model also fit the corresponding field data. When parameterized with field data, the model showed that stomata of aspen were the most sensitive of the three species to VPD, and stomata of black spruce were the least sensitive. For jack pine and aspen, stomata of foliage in the upper canopy were significantly more sensitive than stomata of foliage in the lower canopy. Vapor pressure difference had a greater impact on A n of aspen than on A n of the conifers as a result of aspen's greater stomatal sensitivity to VPD and greater slope of the relationship between A n and intercellular CO 2 concentration ( C i ). During the 1994 growing season, VPD averaged 1.0 kPa, corresponding to ratios of C i to ambient CO 2 of 0.77, 0.71 and 0.81 for jack pine, black spruce and aspen, respectively. We conclude that increases in VPD at the leaf surface in response to climate change should affect the absolute CO 2 and H 2 O fluxes per unit leaf area of the aspen component of a boreal forest landscape more than those of the conifer component. Key words aspen black spruce jack pine photosynthesis stomatal conductance © 1997 Heron Publishing—Victoria Canada « Previous | Next Article » Table of Contents This Article Tree Physiol (1997) 17 (8-9): 521-535. doi: 10.1093/treephys/17.8-9.521 » Abstract Free Full Text (PDF) Free Classifications Original Article Services Article metrics Alert me when cited Alert me if corrected Find similar articles Similar articles in Web of Science Similar articles in PubMed Add to my archive Download citation Request Permissions Citing Articles Load citing article information Citing articles via CrossRef Citing articles via Scopus Citing articles via Web of Science Citing articles via Google Scholar Google Scholar Articles by Dang, Q. L. Articles by Collatz, G. J. Search for related content PubMed PubMed citation Articles by Dang, Q. L. Articles by Margolis, H. A. Articles by Coyea, M. R. Articles by Sy, M. Articles by Collatz, G. J. Related Content Load related web page information Share Email this article CiteULike Delicious Facebook Google+ Mendeley Twitter What's this? Search this journal: Advanced » Current Issue November 2015 35 (11) Alert me to new issues The Journal About this journal Rights & permissions We are mobile – find out more This journal is a member of the Committee on Publication Ethics (COPE) Journals Career Network Impact factor: 3.655 5-Yr impact factor: 3.787 Ram Oren, Editor-in-Chief Torgny Näsholm, Associate Editor-In-Chief Sari Palmroth, Managing Editor View the full editorial board For Authors Instructions to authors Services for authors Online submission instructions Submit Now! Author Self Archiving Policy Open access options available for authors - visit Oxford Open Corporate Services What we offer Advertising sales Reprints Supplements Alerting Services Email table of contents XML RSS feed var taxonomies = ("SCI01210"); Most Most Read Nutrition of mangroves Relationships of tree height and diameter at breast height revisited: analyses of stem growth using 20-year data of an even-aged Chamaecyparis obtusa stand A method for routine measurements of total sugar and starch content in woody plant tissues Non-structural carbohydrates in woody plants compared among laboratories Size, shape and surface morphology of starch granules from Norway spruce needles revealed by transmission electron microscopy and atomic force microscopy: effects of elevated CO2 concentration » View all Most Read articles Most Cited Scaling of angiosperm xylem structure with safety and efficiency Evaluation of transpiration in a Douglas-fir stand by means of sap flow measurements A mathematical and statistical analysis of the curves illustrating vulnerability of xylem to cavitation Carbon dynamics in trees: feast or famine? Nighttime transpiration in woody plants from contrasting ecosystems » View all Most Cited articles Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department. Online ISSN 1758-4469 - Print ISSN 0829-318X Copyright © 2015 Oxford University Press Oxford Journals Oxford University Press Site Map Privacy Policy Cookie Policy Legal Notices Frequently Asked Questions Other Oxford University Press sites: Oxford University Press Oxford Journals China Oxford Journals Japan Academic & Professional books Children's & Schools Books Dictionaries & Reference Dictionary of National Biography Digital Reference English Language Teaching Higher Education Textbooks International Education Unit Law Medicine Music Online Products & Publishing Oxford Bibliographies Online Oxford Dictionaries Online Oxford English Dictionary Oxford Language Dictionaries Online Oxford Scholarship Online Reference Rights and Permissions Resources for Retailers & Wholesalers Resources for the Healthcare Industry Very Short Introductions World's Classics function fnc_onDomLoaded() { var query_context = getQueryContext(); PF_initOIUnderbar(query_context,":QS:default","","JRN"); PF_insertOIUnderbar(0); }; if (window.addEventListener) { window.addEventListener('load', fnc_onDomLoaded, false); } else if (window.attachEvent) { window.attachEvent('onload', fnc_onDomLoaded); } var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-189672-16"); pageTracker._setDomainName(".oxfordjournals.org"); pageTracker._trackPageview(); } catch(err) {}

Journal

Tree PhysiologyOxford University Press

Published: Aug 1, 1997

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