TY - JOUR
T1 - Internal conductance to CO2 transfer of adult Fagus sylvatica
T2 - Variation between sun and shade leaves and due to free-air ozone fumigation
AU - Warren, C. R.
AU - Löw, M.
AU - Matyssek, R.
AU - Tausz, M.
N1 - Funding Information:
The present study is part of the project “CASIROZ—The carbon sink strength of beech in a changing environment: Experimental risk assessment by mitigation of chronic ozone impact” (EVK2-2002-00165) funded within the fifth RTD Framework Programme of the European Union. This work was partially supported by funding from the Australian Research Council to CRW and “Deutsche Forschungsgemeinschaft” (DFG) through SFB 607 “Growth and Parasite Defence—Competition for Resources in Economic Plants from Agronomy and Forestry”. The School of Forest and Ecosystem Science of the University of Melbourne is supported by the Victorian Department of Sustainability and Environment (DSE).
PY - 2007/3
Y1 - 2007/3
N2 - Two separate objectives were considered in this study. We examined (1) internal conductance to CO2 (gi) and photosynthetic limitations in sun and shade leaves of 60-year-old Fagus sylvatica, and (2) whether free-air ozone fumigation affects gi and photosynthetic limitations. gi and photosynthetic limitations were estimated in situ from simultaneous measurements of gas exchange and chlorophyll fluorescence on attached sun and shade leaves of F. sylvatica. Trees were exposed to ambient air (1× O3) and air with twice the ambient ozone concentration (2× O3) in a free-air ozone canopy fumigation system in southern Germany (Kranzberg Forest). gi varied between 0.12 and 0.24 mol m-2 s-1 and decreased CO2 concentrations from intercellular spaces (Ci) to chloroplastic (Cc) by approximately 55 μmol mol-1. The maximum rate of carboxylation (Vcmax) was 22-39% lower when calculated on a Ci basis compared with a Cc basis. gi was approximately twice as large in sun leaves compared to shade leaves. Relationships among net photosynthesis, stomatal conductance and gi were very similar in sun and shade leaves. This proportional scaling meant that neither Ci nor Cc varied between sun and shade leaves. Rates of net photosynthesis and stomatal conductance were about 25% lower in the 2× O3 treatment compared with 1× O3, while Vcmax was unaffected. There was no evidence that gi was affected by ozone.
AB - Two separate objectives were considered in this study. We examined (1) internal conductance to CO2 (gi) and photosynthetic limitations in sun and shade leaves of 60-year-old Fagus sylvatica, and (2) whether free-air ozone fumigation affects gi and photosynthetic limitations. gi and photosynthetic limitations were estimated in situ from simultaneous measurements of gas exchange and chlorophyll fluorescence on attached sun and shade leaves of F. sylvatica. Trees were exposed to ambient air (1× O3) and air with twice the ambient ozone concentration (2× O3) in a free-air ozone canopy fumigation system in southern Germany (Kranzberg Forest). gi varied between 0.12 and 0.24 mol m-2 s-1 and decreased CO2 concentrations from intercellular spaces (Ci) to chloroplastic (Cc) by approximately 55 μmol mol-1. The maximum rate of carboxylation (Vcmax) was 22-39% lower when calculated on a Ci basis compared with a Cc basis. gi was approximately twice as large in sun leaves compared to shade leaves. Relationships among net photosynthesis, stomatal conductance and gi were very similar in sun and shade leaves. This proportional scaling meant that neither Ci nor Cc varied between sun and shade leaves. Rates of net photosynthesis and stomatal conductance were about 25% lower in the 2× O3 treatment compared with 1× O3, while Vcmax was unaffected. There was no evidence that gi was affected by ozone.
KW - Internal conductance
KW - Mesophyll conductance
KW - Ozone
KW - Photosynthesis
KW - Stomatal conductance
KW - Transfer conductance
UR - http://www.scopus.com/inward/record.url?scp=33751341077&partnerID=8YFLogxK
U2 - 10.1016/j.envexpbot.2005.11.004
DO - 10.1016/j.envexpbot.2005.11.004
M3 - Article
AN - SCOPUS:33751341077
SN - 0098-8472
VL - 59
SP - 130
EP - 138
JO - Environmental and Experimental Botany
JF - Environmental and Experimental Botany
IS - 2
ER -