This monograph has been written from our convic- tion that the present notions of the state of wa- ter in osmotic systems are obscure, if not incor- rect. The basic ideas presented herein are for us not original, but they have previously been ig- nored. We shall attempt again to bring the essen- tial concepts to the attention of the functional biologist with the hope that they will be duly considered and accepted. We even dare to expect that many will be able to recognize the inherent beauty in the old idea that all colligative pro- perties of water stem exclusively from the fact that the water is under tension, regardless of the particular process by which it has been placed under tension in the biological system. The ideas are so simple and so obvious that we are amazed biologists have not already recognized their va- lidity even without the assistance of physical chemistry and chemical thermodynamics, which deal with the subject of water under pressure in solu- tions and in matrices.
We expect that drawing at- tention to experimental evidence heretofore not available will assist the more conservative phys- iologist to reconsider and reject fictitious no- tions about the properties of water in a solution.
Sprache
Verlagsort
Verlagsgruppe
Zielgruppe
Für Beruf und Forschung
Research
Illustrationen
Gewicht
ISBN-13
978-3-540-07663-6 (9783540076636)
DOI
10.1007/978-3-642-66339-0
Schweitzer Klassifikation
I. Perspectives on the Mechanism of Osmosis and Imbibition.- I. The Founders.- Van't Hoff's Solute-Gas Analog.- Van't Hoff on the Mechanism of Osmosis.- II. Thermodynamic Laissez Faire.- III. Some Fundamental Experimental Facts.- 1. Lowered Vapor Pressure Over Solutions and Unsaturated Gels.- 2. Osmosis by Bulk Flow.- 3. Equivalence of Hydraulic and Osmotic Flux.- 4. Osmotic Flux Moving against the Water Potential.- IV. Water Tension Theory.- Physical Models of Imbibition and Osmosis.- Cohesiveness of Water.- A. Matrices.- Measurements of Tension and the Role of the Free Surface.- Gravitational Pressure Gradients.- Negative Pressure by Crowding and Conformational Changes.- B. Matrix-Solute Balance.- Sap Rising in Trees and Vines.- Sap Tension by Rate of Filtration..- Gravitational Pressure Gradients in the Xylem 2.- At Last: Measuring Negative Sap Pressure.- Negative Solvent Pressure in Xylem and Cells.- Pressure Profiles through an Osmotic Model System.- C. Solutions and the Role of the Boundary.- Solvent Tension and the Curved Surface.- The Kelvin-Poynting Gravitational Column.- Hulett and the Solvent Tension Theory.- Epilog I: The Tortuous Way of Finding out.- Brownian Motion and Jean Perrin: Solute and Solvent as Independent Kinetic Units.- Epilog II: The Chemical Versus the Physical Mind.- Further Theoretical Support for Solute-Solvent Coupling at the Free Surface.- Other Applications of the Kelvin-Poynting Column.- D. Non Equilibrium States and the Role of Drag.- Layering Water on the Surface of a Solution.- Hydrostatic Pressures in Stirred Suspensions.- E. Where is the Site of Coupling between Solute and Solvent?.- Effect of Crowding on Osmotic Pressure.- Effect of Gravity on Osmotic Pressure.- Magnetoosmosis.- F. Answers to Part III.- V. Water Concentration Theory.- Pressure Drop at the Pore Openings.- Osmotic Flow against the Water Potential.- Anti-Gravity Devices in Trees.- Comments.- Concluding Remarks.- II. Some Reversible Thermodynamic Relationships at Equilibrium.- Some Basic Thermodynamic Statements.- The Poynting Relation.- The Clapeyron Equation.- Application of Thermodynamic Statements to Solutions.- Ideal Solution.- Interpreting the Change in Chemical Potential of a Solvent Homogeneous in a Solution.- III. Toward Understanding the Colligative Properties of a Solution.- I. Osmotic Pressure.- Distribution of Vapor Molecules in a Gravity Field.- Thermal Pressure of the Solute and Solvent Molecules within the Solution.- Induction of Enhanced Tension in the Solvent of a Solution.- Distribution of Solute Molecules within a Solution in a Gravity Field.- The Weight of the Column Below the Surface of the Solution and its Correlation with the Concentration at the Free Surface and the Osmotic Pressure of the Solution.- Vapor Pressure of a Distensible Liquid under Tension.- Summary of the Conditions which Describe the Solution in a Gravity Osmometer shown in Figs. 52 and 53.- The Greater Tension in the Solvent within a Solution Alters its Osmotic Pressure with Respect to Pure Solvent.- Height of Solution Column in a Cylindrical Gravity Osmometer.- II. Vapor Pressure.- III. Melting Point.- IV. Boiling Point.- Experimental Confirmation of Relationship between Osmotic Pressure and Lowering of Vapor Pressure.- IV. The Chemical Potential of Water.- In a Solution.- In a Matrix.- Chemical Potential of Solvent in Real Solutions.- Glossary of Terms.- References.
