Adjustments in hydraulic architecture of Pinus palustris maintain similar stomatal conductance in xeric and mesic habitats.

We investigated relationships between whole-tree hydraulic architecture and stomatal conductance in Pinus palustris Mill. (longleaf pine) across habitats that differed in soil properties and habitat structure. Trees occupying a xeric habitat (characterized by sandy, well-drained soils, higher nitrogen availability and lower overstory tree density) were shorter in stature and had lower sapwood-to-leaf area ratio (A(S):A(L)) than trees in a mesic habitat. The soil-leaf water potential gradient (psiS - psiL) and leaf-specific hydraulic conductance (kL) were similar between sites, as was tissue-specific hydraulic conductivity (Ks) of roots. Leaf and canopy stomatal conductance (gs and Gs, respectively) were also similar between sites, and they tended to be somewhat higher at the xeric site during morning hours when vapour pressure deficit (D) was low. A hydraulic model incorporating tree height, A(S):A(L) and psiS-psiL accurately described the observed variation in individual tree G(Sref) (G(S) at D = 1 kPa) across sites and indicated that tree height was an important determinant of G(Sref) across sites. This, combined with a 42% higher root-to-leaf area ratio (A(R):A(L)) at the xeric site, suggests that xeric site trees are hydraulically well equipped to realize equal--and sometimes higher potential for conductance compared with trees on mesic sites. However, a slightly more sensitive stomatal closure response to increasing D observed in xeric site trees suggests that this potential for higher conductance may only be reached when D is low and when the capacity of the hydraulic system to supply water to foliage is not greatly challenged.

[1]  G. Downes,et al.  Effects of bending stress on taper and growth of stems of youngEucalyptus regnans trees , 1996, Trees.

[2]  C. R. Ford.  Variable distributions of water as a transpiration source , 2004 .

[3]  R. Mitchell,et al.  Diurnal and seasonal variability in the radial distribution of sap flow: predicting total stem flow in Pinus taeda trees. , 2004, Tree physiology.

[4]  D. Woodruff,et al.  Integrated responses of hydraulic architecture, water and carbon relations of western hemlock to dwarf mistletoe infection , 2004 .

[5]  R. Oren,et al.  Stomatal sensitivity to vapor pressure deficit and its relationship to hydraulic conductance in Pinus palustris. , 2004, Tree physiology.

[6]  R. Mitchell,et al.  Assessing variation in the radial profile of sap flux density in Pinus species and its effect on daily water use. , 2004, Tree physiology.

[7]  J. Sperry,et al.  Root and stem xylem embolism, stomatal conductance, and leaf turgor in Acer grandidentatum populations along a soil moisture gradient , 1996, Oecologia.

[8]  Nicanor Z. Saliendra,et al.  Influence of leaf water status on stomatal response to humidity, hydraulic conductance, and soil drought in Betula occidentalis , 1995, Planta.

[9]  S. B. Jack,et al.  Phenological patterns of mature longleaf pine (Pinus palustris Miller) under two different soil moisture regimes , 2003 .

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

[11]  Maurizio Mencuccini,et al.  The ecological significance of long-distance water transport: short-term regulation, long-term acclimation and the hydraulic costs of stature across plant life forms , 2003 .

[12]  M. G. Ryan,et al.  The relationship between tree height and leaf area: sapwood area ratio , 2002, Oecologia.

[13]  R. Mitchell,et al.  Soil nitrogen dynamics in a fire-maintained forest ecosystem: results over a 3-year burn interval , 2002 .

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

[15]  M. Drew,et al.  FOREST ECOSYSTEMS OF A LOWER GULF COASTAL PLAIN LANDSCAPE: MULTIFACTOR CLASSIFICATION AND ANALYSIS , 2001 .

[16]  R. Addington.  WATER USE PATTERNS AND STOMATAL RESPONSES TO ENVIRONMENT IN LONGLEAF PINE ON CONTRASTING SITES , 2001 .

[17]  Michael G. Ryan,et al.  Stomatal conductance and photosynthesis vary linearly with plant hydraulic conductance in ponderosa pine , 2001 .

[18]  J. Sperry,et al.  Influence of nutrient versus water supply on hydraulic architecture and water balance in Pinus taeda , 2000 .

[19]  M. G. Ryan,et al.  Transpiration and whole-tree conductance in ponderosa pine trees of different heights , 2000, Oecologia.

[20]  E. DeLucia,et al.  Xylem conductivity and vulnerability to cavitation of ponderosa pine growing in contrasting climates. , 2000, Tree physiology.

[21]  Ram Oren,et al.  Analyses of assumptions and errors in the calculation of stomatal conductance from sap flux measurements. , 2000, Tree physiology.

[22]  John Tenhunen,et al.  The effect of tree height on crown level stomatal conductance , 2000 .

[23]  D. Ellsworth,et al.  Influence of soil porosity on water use in Pinus taeda , 2000, Oecologia.

[24]  Nathan Phillips,et al.  Survey and synthesis of intra‐ and interspecific variation in stomatal sensitivity to vapour pressure deficit , 1999 .

[25]  B. Bond,et al.  Stomatal behavior of four woody species in relation to leaf-specific hydraulic conductance and threshold water potential. , 1999, Tree physiology.

[26]  Stephen D. Pecot,et al.  Patterns and controls of ecosystem function in longleaf pine - wiregrass savannas. I. Aboveground net primary productivity , 1999 .

[27]  R. Mitchell,et al.  Patterns and controls of ecosystem function in longleaf pine — wiregrass savannas. II. Nitrogen dynamics , 1999 .

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

[29]  R. Mitchell,et al.  Influences of Frequent Cool-season Burning Across a Soil Moisture Gradient on Oak Community Structure in Longleaf Pine Ecosystems , 1999 .

[30]  G. Goldstein,et al.  Regulation of water flux through trunks, branches, and leaves in trees of a lowland tropical forest , 1998, Oecologia.

[31]  E. Steudle.  Review article. How does water get through roots , 1998 .

[32]  H. L. Allen,et al.  Leaf Area and Above- and Belowground Growth Responses of Loblolly Pine to Nutrient and Water Additions , 1998, Forest Science.

[33]  E. Steudle,et al.  How does water get through roots , 1998 .

[34]  Frederick R. Adler,et al.  Limitation of plant water use by rhizosphere and xylem conductance: results from a model , 1998 .

[35]  G. Katul,et al.  Scaling xylem sap flux and soil water balance and calculating variance: a method for partitioning water flux in forests , 1998 .

[36]  William T. Pockman,et al.  Use of centrifugal force in the study of xylem cavitation , 1997 .

[37]  G. Downes,et al.  Effects of bending stress on taper and growth of stems of young , 1996 .

[38]  Maurizio Mencuccini,et al.  Climate influences the leaf area/sapwood area ratio in Scots pine. , 1995, Tree physiology.

[39]  W. Schlesinger,et al.  Biomass Allocation of Montane and Desert Ponderosa Pine: An Analog for Response to Climate Change , 1994 .

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

[41]  F. Davies,et al.  Comparison of methods for estimating surface area of water-stressed and fully hydrated pine needle segments for gas exchange analysis. , 1992, Tree physiology.

[42]  J. N. Long,et al.  Influence of leaf area and canopy structure on size-density relations in even-aged lodgepole pine stands , 1992 .

[43]  D. Hartnett,et al.  Pine flatwoods and dry prairies , 1990 .

[44]  J. P. Kimmins,et al.  Above- and below-ground biomass and production of lodgepole pine on sites with differing soil moisture regimes , 1989 .

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

[46]  S. Stafford,et al.  Twenty-four Years of Ponderosa Pine Growth in Relation to Canopy Leaf Area and Understory Competition , 1987, Forest Science.

[47]  J. N. Long,et al.  Variation in Sapwood Area-Leaf Area Relations Within Two Stands of Lodgepole Pine , 1986 .

[48]  P. Jarvis,et al.  Conducting sapwood area, foliage area, and permeability in mature trees of Piceasitchensis and Pinuscontorta , 1984 .

[49]  P. Jarvis,et al.  Stomatal conductance, transpiration, and resistance to water uptake in a Pinussylvestris spacing experiment , 1984 .

[50]  D. H. Knight,et al.  Biomass and leaf area in contrasting lodgepole pine forests , 1984 .

[51]  J. Aber,et al.  Changes in Forest Canopy Structure along a Site Quality Gradient in Southern Wisconsin , 1982 .

[52]  Paul R. Lowe,et al.  The Computation of Saturation Vapor Pressure , 1974 .

[53]  F. Heyward.  The Root System of Longleaf Pine on the Deep Sands of Western Florida , 1933 .