Biophysical properties and functional significance of stem water storage tissues in Neotropical savanna trees.

Biophysical characteristics of sapwood and outer parenchyma water storage compartments were studied in stems of eight dominant Brazilian Cerrado tree species to assess the impact of differences in tissue capacitance on whole-plant water relations. The rate of decline in tissue water potential with relative water content (RWC) was greater in the outer parenchyma than in the sapwood for most of the species, resulting in tissue-and species-specific differences in capacitance. Sapwood capacitance on a tissue volume basis ranged from 40 to 160 kg m-3 MPa-1, whereas outer parenchyma capacitance ranged from 25 to only 60 kg m-3 MPa-1. In addition, osmotic potentials at full turgor and at the turgor loss point were more negative for the outer parenchyma compared with the sapwood, and the maximum bulk elastic modulus was higher for the outer parenchyma than for the sapwood. Sapwood capacitance decreased linearly with increasing sapwood density across species, but there was no significant correlation between outer parenchyma capacitance and tissue density. Midday leaf water potential, the total hydraulic conductance of the soil/leaf pathway and stomatal conductance to water vapour (gs) all increased with stem volumetric capacitance, or with the relative contribution of stored water to total daily transpiration. However, the difference between the pre-dawn water potential of non-transpiring leaves and the weighted average soil water potential, a measure of the water potential disequilibrium between the plant and soil, increased asymptotically with total stem capacitance across species, implying that overnight recharge of water storage compartments was incomplete in species with greater capacitance. Overall, stem capacitance contributes to homeostasis in the diurnal and seasonal water balance of Cerrado trees.

[1]  G. Goldstein,et al.  Removal of nutrient limitations by long-term fertilization decreases nocturnal water loss in savanna trees. , 2007, Tree physiology.

[2]  M. Tyree,et al.  Water-storage capacity ofThuja, Tsuga andAcer stems measured by dehydration isotherms , 1990, Planta.

[3]  D. Woodruff,et al.  Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques. , 2006, Plant, cell & environment.

[4]  Frederick C. Meinzer,et al.  Mechanisms contributing to seasonal homeostasis of minimum leaf water potential and predawn disequilibrium between soil and plant water potential in Neotropical savanna trees , 2005, Trees.

[5]  G. Goldstein,et al.  Processes preventing nocturnal equilibration between leaf and soil water potential in tropical savanna woody species. , 2004, Tree physiology.

[6]  W. Hoffmann,et al.  Constraints to seedling success of savanna and forest trees across the savanna-forest boundary , 2004, Oecologia.

[7]  J. Ehleringer,et al.  Water relations of stem succulent trees in north-central Baja California , 1990, Oecologia.

[8]  W. Hoffmann,et al.  Comparative fire ecology of tropical savanna and forest trees , 2003 .

[9]  G. Goldstein,et al.  Whole-tree water transport scales with sapwood capacitance in tropical forest canopy trees , 2003 .

[10]  M. G. Ryan,et al.  Reliance on stored water increases with tree size in three species in the Pacific Northwest. , 2003, Tree physiology.

[11]  F. Do,et al.  Influence of natural temperature gradients on measurements of xylem sap flow with thermal dissipation probes. 1. Field observations and possible remedies. , 2002, Tree physiology.

[12]  Frederick C Meinzer,et al.  Hydraulic redistribution of soil water by neotropical savanna trees , 2001 .

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

[14]  T Vesala,et al.  Tree stem diameter variations and transpiration in Scots pine: an analysis using a dynamic sap flow model. , 2001, Tree physiology.

[15]  Yoshikazu Kobayashi,et al.  Water flow and hydraulic characteristics of Japanese red pine and oak trees , 2001 .

[16]  R. Zweifel,et al.  Dynamics of water storage in mature subalpine Picea abies: temporal and spatial patterns of change in stem radius. , 2001, Tree physiology.

[17]  G Goldstein,et al.  Water transport in trees: current perspectives, new insights and some controversies. , 2001, Environmental and experimental botany.

[18]  R. Benyon,et al.  Nighttime water use in an irrigated Eucalyptus grandis plantation. , 1999, Tree physiology.

[19]  G. Goldstein,et al.  Partitioning of soil water among tree species in a Brazilian Cerrado ecosystem. , 1999, Tree physiology.

[20]  Frederick C. Meinzer,et al.  Potential errors in measurement of nonuniform sap flow using heat dissipation probes. , 1999, Tree physiology.

[21]  L. Donovan,et al.  Predawn disequilibrium between plant and soil water potentials in two cold-desert shrubs , 1999, Oecologia.

[22]  R. Oren,et al.  Sap-flux-scaled transpiration responses to light, vapor pressure deficit, and leaf area reduction in a flooded Taxodium distichum forest. , 1999, Tree physiology.

[23]  G. Goldstein,et al.  Atmospheric and hydraulic limitations on transpiration in Brazilian cerrado woody species , 1999 .

[24]  A. Sellin.  Does pre-dawn water potential reflect conditions of equilibrium in plant and soil water status? , 1999 .

[25]  J. Boone Kauffman,et al.  Ecosystem structure in the Brazilian Cerrado: a vegetation gradient of aboveground biomass, root mass and consumption by fire , 1998, Journal of Tropical Ecology.

[26]  Frederick C. Meinzer,et al.  Stem water storage and diurnal patterns of water use in tropical forest canopy trees , 1998 .

[27]  Abhijit Nagchaudhuri,et al.  Time constant for water transport in loblolly pine trees estimated from time series of evaporative demand and stem sapflow , 1997, Trees.

[28]  S. Wofsy,et al.  Modelling the soil-plant-atmosphere continuum in a Quercus-Acer stand at Harvard Forest : the regulation of stomatal conductance by light, nitrogen and soil/plant hydraulic properties , 1996 .

[29]  N. Holbrook.  Stem Water Storage , 1995 .

[30]  N. Holbrook,et al.  Water balance in the arborescent palm, Sabal palmetto. II. Transpiration and stem water storage , 1992 .

[31]  Park S. Nobel,et al.  Physicochemical and Environmental Plant Physiology , 1991 .

[32]  G. Goldstein,et al.  Comparative gas exchange of leaves and bark in three stem succulents of Baja California , 1990 .

[33]  M. Tyree,et al.  A dynamic model for water flow in a single tree: evidence that models must account for hydraulic architecture. , 1988, Tree physiology.

[34]  A. Granier,et al.  Evaluation of transpiration in a Douglas-fir stand by means of sap flow measurements. , 1987, Tree physiology.

[35]  Thomas J. Givnish,et al.  On the economy of plant form and function. , 1988 .

[36]  P. Jarvis,et al.  A dynamic model for studying flow of water in single trees. , 1986, Tree physiology.

[37]  G. Goldstein,et al.  Patrones diarios y estacionales en las relaciones hídricas de árboles siempreverdes de la sabana tropical , 1986 .

[38]  G. Goldstein,et al.  Adaptations for water and thermal balance in Andean giant rosette plants , 1986 .

[39]  N. Turner,et al.  Phase and amplitude relations between transpiration, water potential and stem shrinkage , 1985 .

[40]  A. Granier.  Une nouvelle méthode pour la mesure du flux de sève brute dans le tronc des arbres , 1985 .

[41]  G. Goldstein,et al.  The role of capacitance in the water balance of Andean giant rosette species , 1984 .

[42]  M. Zimmermann.  Xylem Structure and the Ascent of Sap , 1983, Springer Series in Wood Science.

[43]  Richard H. Waring,et al.  The contribution of stored water to transpiration in Scots pine , 1979 .

[44]  M. G. Ferri,et al.  Ecologia do cerrado , 1979 .

[45]  Richard H. Waring,et al.  Sapwood water storage: its contribution to transpiration and effect upon water conductance through the stems of old‐growth Douglas‐fir , 1978 .

[46]  Melvin T. Tyree,et al.  The Measurement of the Turgor Pressure and the Water Relations of Plants by the Pressure-bomb Technique , 1972 .