Optimal stomatal conductance in relation to photosynthesis in climatically contrasting Eucalyptus species under drought.

Models of stomatal conductance (g(s)) are based on coupling between g(s) and CO(2) assimilation (A(net)), and it is often assumed that the slope of this relationship ('g(1) ') is constant across species. However, if different plant species have adapted to different access costs of water, then there will be differences in g(1) among species. We hypothesized that g(1) should vary among species adapted to different climates, and tested the theory and its linkage to plant hydraulics using four Eucalyptus species from different climatic origins in a common garden. Optimal stomatal theory predicts that species from sub-humid zones have a lower marginal water cost of C gain, hence lower g(1) than humid-zone species. In agreement with the theory that g(1) is related to tissue carbon costs for water supply, we found a relationship between wood density and g(1) across Eucalyptus species of contrasting climatic origins. There were significant reductions in the parameter g(1) during drought in humid but not sub-humid species, with the latter group maintaining g(1) in drought. There are strong differences in stomatal behaviour among related tree species in agreement with optimal stomatal theory, and these differences are consistent with the economics involved in water uptake and transport for carbon gain.

[1]  Uwe G. Hacke,et al.  Functional and Ecological Xylem Anatomy , 2015, Springer International Publishing.

[2]  David T. Tissue,et al.  Effects of elevated atmospheric [CO2] on instantaneous transpiration efficiency at leaf and canopy scales in Eucalyptus saligna , 2012 .

[3]  D. Ellsworth,et al.  Elevated CO2 affects photosynthetic responses in canopy pine and subcanopy deciduous trees over 10 years: a synthesis from Duke FACE , 2012 .

[4]  T. Brodribb,et al.  Stomatal innovation and the rise of seed plants. , 2012, Ecology letters.

[5]  A. Verhoef,et al.  Towards an improved and more flexible representation of water stress in coupled photosynthesis-stomatal conductance models. , 2011 .

[6]  Frans Bongers,et al.  Plant Functional Traits and the Distribution of West African Rain Forest Trees along the Rainfall Gradient , 2011 .

[7]  Paolo De Angelis,et al.  Reconciling the optimal and empirical approaches to modelling stomatal conductance , 2011 .

[8]  T. Brodribb,et al.  Passive Origins of Stomatal Control in Vascular Plants , 2011, Science.

[9]  Hervé Cochard,et al.  An overview of models of stomatal conductance at the leaf level. , 2010, Plant, cell & environment.

[10]  R. McMurtrie,et al.  Whole-tree chambers for elevated atmospheric CO2 experimentation and tree scale flux measurements in south-eastern Australia: the Hawkesbury Forest Experiment. , 2010 .

[11]  Pete Smith,et al.  Integrating plant–soil interactions into global carbon cycle models , 2009 .

[12]  Harry T. Valentine,et al.  Optimal Function Explains Forest Responses to Global Change , 2009 .

[13]  Sari Palmroth,et al.  Leaf stomatal responses to vapour pressure deficit under current and CO(2)-enriched atmosphere explained by the economics of gas exchange. , 2008, Plant, cell & environment.

[14]  Markus Reichstein,et al.  Mean annual GPP of Europe derived from its water balance , 2007 .

[15]  J. Flexas,et al.  Water relations and stomatal characteristics of Mediterranean plants with different growth forms and leaf habits: responses to water stress and recovery , 2007, Plant and Soil.

[16]  Benjamin Smith,et al.  Implementing plant hydraulic architecture within the LPJ Dynamic Global Vegetation Model , 2006 .

[17]  Seasonal patterns of leaf gas exchange and water relations in dry rain forest trees of contrasting leaf phenology. , 2006, Tree physiology.

[18]  P. Franks.  Higher rates of leaf gas exchange are associated with higher leaf hydrodynamic pressure gradients. , 2006, Plant, cell & environment.

[19]  T. Buckley,et al.  The control of stomata by water balance. , 2005, The New phytologist.

[20]  N. Holbrook,et al.  Leaf hydraulic capacity in ferns, conifers and angiosperms: impacts on photosynthetic maxima. , 2004, The New phytologist.

[21]  P. Reich,et al.  Photosynthesis, carboxylation and leaf nitrogen responses of 16 species to elevated pCO2 across four free‐air CO2 enrichment experiments in forest, grassland and desert , 2004 .

[22]  P. Dart,et al.  Selection of species and provenances for low-rainfall areas: physiological responses of Eucalyptus cloeziana and Eucalyptus argophloia to seasonal conditions in subtropical Queensland , 2004 .

[23]  A. Goldstein,et al.  A comparison of three approaches to modeling leaf gas exchange in annually drought-stressed ponderosa pine forests. , 2004, Tree physiology.

[24]  G. Farquhar,et al.  13C discrimination during CO2 assimilation by the terrestrial biosphere , 1994, Oecologia.

[25]  J. Berry,et al.  A biochemical model of photosynthetic CO2 assimilation in leaves of C3 species , 1980, Planta.

[26]  D. Baldocchi,et al.  Seasonal trends in photosynthetic parameters and stomatal conductance of blue oak (Quercus douglasii) under prolonged summer drought and high temperature. , 2003, Tree physiology.

[27]  Ray Leuning,et al.  A coupled model of stomatal conductance, photosynthesis and transpiration , 2003 .

[28]  G. Katul,et al.  Relationship between plant hydraulic and biochemical properties derived from a steady‐state coupled water and carbon transport model , 2003 .

[29]  P. Reich,et al.  Least‐Cost Input Mixtures of Water and Nitrogen for Photosynthesis , 2002, The American Naturalist.

[30]  M. Westoby,et al.  ECOLOGICAL STRATEGIES : Some Leading Dimensions of Variation Between Species , 2002 .

[31]  David R. Anderson,et al.  Avoiding pitfalls when using information-theoretic methods , 2002 .

[32]  A. Arneth,et al.  Response of central Siberian Scots pine to soil water deficit and long‐term trends in atmospheric CO2 concentration , 2002 .

[33]  R. Oren,et al.  Water deficits and hydraulic limits to leaf water supply. , 2002, Plant, cell & environment.

[34]  G. Katul,et al.  Modelling assimilation and intercellular CO2 from measured conductance: a synthesis of approaches , 2000 .

[35]  G. Katul,et al.  Modeling CO2 and water vapor turbulent flux distributions within a forest canopy , 2000 .

[36]  D. White,et al.  Leaf water relations and stomatal behavior of four allopatric Eucalyptus species planted in Mediterranean southwestern Australia. , 2000, Tree physiology.

[37]  J. Sperry.  Hydraulic constraints on plant gas exchange , 2000 .

[38]  G. Mohren,et al.  Modeling daily gas exchange of a Douglas-fir forest: comparison of three stomatal conductance models with and without a soil water stress function. , 2000, Tree physiology.

[39]  D. Eamus,et al.  Optimization theory of stomatal behaviour I. A critical evaluation of five methods of calculation , 1999 .

[40]  D. Eamus,et al.  Optimization Theory Of Stomatal Behaviour - Ii. Stomatal Responses Of Several Tree Species Of North Australia To Changes In Light, Soil And Atmospheric Water Content And Temperature , 1999 .

[41]  H. Jones.  Stomatal control of photosynthesis and transpiration , 1998 .

[42]  G. Farquhar,et al.  Correlations Between Carbon Isotope Discrimination and Climate of Native Habitats for Diverse Eucalypt Taxa Growing in a Common Garden , 1996 .

[43]  R. Leuning.  A critical appraisal of a combined stomatal‐photosynthesis model for C3 plants , 1995 .

[44]  J. Sperry,et al.  The Effect of Reduced Hydraulic Conductance on Stomatal Conductance and Xylem Cavitation , 1993 .

[45]  William J. Davies,et al.  Integration of hydraulic and chemical signalling in the control of stomatal conductance and water status of droughted plants , 1993 .

[46]  G. Collatz,et al.  Physiological and environmental regulation of stomatal conductance, photosynthesis and transpiration: a model that includes a laminar boundary layer , 1991 .

[47]  J. Lloyd.  Modelling Stomatal Responses to Environment in Macadamia integrifolia , 1991 .

[48]  P. Reich,et al.  Influence of pre-dawn water potential and soil-to-leaf hydraulic conductance on maximum daily leaf diffusive conductance in two oak species , 1989 .

[49]  Melvin T. Tyree,et al.  A method for measuring hydraulic conductivity and embolism in xylem , 1988 .

[50]  T. Givnish.  Optimal stomatal conductance, allocation of energy between leaves and roots, and the marginal cost of transpiration , 1986 .

[51]  G. Farquhar,et al.  Isotopic Composition of Plant Carbon Correlates With Water-Use Efficiency of Wheat Genotypes , 1984 .

[52]  I. R. Cowan.  Stomatal Behaviour and Environment , 1978 .

[53]  Gordon H. Orians,et al.  A Cost-Income Model of Leaves and Roots with Special Reference to Arid and Semiarid Areas , 1977, The American Naturalist.