Stomatal control of xylem embolism

Abstract. The potential role of stomatal closure in the control of xylem embolism is investigated by means of a simple model of hydraulic flow in plants. Maintenance of a maximally efficient conducting system requires the stomata to close in an appropriate fashion as evaporative demand increases in order to prevent shoot water potentials falling below the threshold value at which cavitations occur. The model showed that the optimal stomatal behaviour required depends on soil water availability. Further analysis of the model demonstrated that there could be certain circumstances where loss of a proportion of the conducting tissue by embolisms can, perhaps surprisingly, be beneficial in terms of maximizing stomatal aperture and hence short-term productivity. The results are discussed in relation to the signals controlling stomatal aperture, and it is shown that (1) optimal control cannot be obtained using information on leaf water potential alone, and (2) information relating to soil water potential is a necessary requirement for optimal control.

[1]  H. Jones.  Gas Exchange in Plant Leaves Having Different Transfer Resistances Through Their Two Surfaces , 1973 .

[2]  Hamlyn G. Jones,et al.  Physiological Aspects of the Control of Water Status in Horticultural Crops , 1990 .

[3]  M. Zimmermann,et al.  Spring filling of xylem vessels in wild grapevine. , 1987, Plant physiology.

[4]  J. Milburn,et al.  STUDIES OF CAVITATION IN ISOLATED VASCULAR BUNDLES AND WHOLE LEAVES OF PLANTAGO MAJOR L. , 1974 .

[5]  I. R. Cowan,et al.  Leaf Conductance in Relation to Rate of CO(2) Assimilation: III. Influences of Water Stress and Photoinhibition. , 1985, Plant physiology.

[6]  M. Tyree,et al.  Xylem dysfunction in Quercus: vessel sizes, tyloses, cavitation and seasonal changes in embolism. , 1990, Tree physiology.

[7]  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.

[8]  H. Jones.  MODELLING DIURNAL TRENDS OF LEAF WATER POTENTIAL IN TRANSPIRING WHEAT , 1978 .

[9]  J. Sperry,et al.  Do woody plants operate near the point of catastrophic xylem dysfunction caused by dynamic water stress? : answers from a model. , 1988, Plant physiology.

[10]  J. Sperry,et al.  Vulnerability of xylem to embolism in a mangrove vs an inland species of Rhizophoraceae , 1988 .

[11]  J. Sperry,et al.  Mechanism of water stress-induced xylem embolism. , 1988, Plant physiology.

[12]  H. Greenway,et al.  Effects of rapidly and slowly permeating osmotica on metabolism. , 1970, Plant physiology.

[13]  T. Hsiao.  Plant Responses to Water Stress , 1973 .

[14]  M. Tyree,et al.  Water stress induced cavitation and embolism in some woody plants , 1986 .

[15]  Melvin T. Tyree,et al.  Water‐stress‐induced xylem embolism in three species of conifers , 1990 .

[16]  A. Tyree,et al.  Vulnerability of Xylem to Cavitation and Embolism , 1989 .

[17]  T. Sinclair,et al.  Who Taught Plants Thermodynamics? The Unfulfilled Potential of Plant Water Potential , 1985 .

[18]  R. Munns,et al.  Soil water status affects the stomatal conductance of fully turgid wheat and sunflower leaves , 1986 .

[19]  H. Jones.  Photosynthesis by Thin Leaf Slices in Solution II. Osmotic Stress and Its Effects on Photosynthesis , 1973 .

[20]  M. Hipkins,et al.  Gas penetration of pit membranes in the xylem of Rhododendron as the cause of acoustically detectable sap cavitation , 1985 .

[21]  F. Meinzer,et al.  Stomatal and hydraulic conductance in growing sugarcane: stomatal adjustment to water transport capacity* , 1990 .

[22]  W. Kaiser,et al.  Effects of water deficit on photosynthetic capacity , 1987 .

[23]  M. Tyree,et al.  Detection of Xylem Cavitation in Corn under Field Conditions. , 1986, Plant physiology.

[24]  T. Sharkey,et al.  Stomatal conductance and photosynthesis , 1982 .

[25]  J. Sperry,et al.  Relationship of Xylem Embolism to Xylem Pressure Potential, Stomatal Closure, and Shoot Morphology in the Palm Rhapis excelsa. , 1986, Plant physiology.