Water Relations In Membrane Transport In Plants And Animals

Water Relations in Membrane Transport in Plants and Animals contains the presentations in a symposium dealing with Water Relations in Membranes in Plants and Animals, during the 27th Annual Fall Meeting of the American Physiological Society held at The University of Pennsylvania, 17-19 August 1976. The purpose of the symposium was to explore the common modes of water regulation in plants and animals. In these proceedings, the mechanisms employed to restrict water flow across plant and metazoan animal cells are described. Putative differences in mechanisms of water regulation retained by plant versus animal cells become inconsequential in the light of the numerous similarities: dependence upon bioelectric potentials maintained across cell membranes, energy dependence of uphill water movement, and solute coupling during water transport. The presentations can be organized into four. The first takes up specific mechanisms of water transport in plants. The second and third parts deal with specific mechanisms in invertebrates and vertebrates, respectively. The fourth part covers generalized mechanisms common to plants and animals.

Aquaporins are channel proteins that facilitate the diffusion of water and small uncharged solutes across cellular membranes. Plant aquaporins form a large family of highly divergent proteins that are involved in many different physiological processes. This book will summarize the recent advances regarding plant aquaporins, their phylogeny, structure, substrate specificity, mechanisms of regulation and roles in various important physiological processes related to the control of water flow and small solute distribution at the cell, tissue and plant level in an ever-changing environment.

Plant Physiology: A Treatise, Volume IX: Water and Solutes in Plants explores problems associated with water and solutes of plants as they grow. This book considers water relations of plant cells, along with transpiration and water balance, the physiology of stomata, ion uptake by roots from the soil, and salt relations of plants. This volume is organized into seven chapters and begins with an introduction to the water potential terminology used by plant physiologists in describing the water relations of plant communities, individual plants and their organs, and plant cells. An account of the elastic properties and hydraulic conductivity of plant cell walls is provided. The following chapters focus on the soil-plant-atmosphere continuum, water uptake and movement through plants, the effects of water deficit on plant development and other processes, and the mechanics of stomatal functioning. The book also introduces the reader to salt relations of plant cells, tissues, and roots as well as long-distance transport in the phloem, and then concludes by discussing the solute composition of cells during development. This book is a valuable resource for teachers, research workers, and students with specific interest in plant physiology.

As plant physiology increased steadily in the latter half of the 19th century, problems of absorption and transport of water and of mineral nutrients and problems of the passage of metabolites from one cell to another were investigated, especially in Germany. JUSTUS VON LIEBIG, who was born in Darmstadt in 1803, founded agricultural chemistry and developed the techniques of mineral nutrition in agricul ture during the 70 years of his life. The discovery of plasmolysis by NAGEL! (1851), the investigation of permeability problems of artificial membranes by TRAUBE (1867) and the classical work on osmosis by PFEFFER (1877) laid the foundations for our understanding of soluble substances and osmosis in cell growth and cell mechanisms. Since living membranes were responsible for controlling both water movement and the substances in solution, "permeability" became a major topic for investigation and speculation. The problems then discussed under that heading included passive permeation by diffusion, Donnan equilibrium adjustments, active transport processes and antagonism between ions. In that era, when organelle isolation by differential centrifugation was unknown and the electron microscope had not been invented, the number of cell membranes, their thickness and their composition, were matters for conjecture. The nature of cell surface membranes was deduced with remarkable accuracy from the reactions of cells to substances in solution. In 1895, OVERTON, in U. S. A. , published the hypothesis that membranes were probably lipid in nature because of the greater penetration by substances with higher fat solubility.

Interest in water will continue to grow for a long time to come. It will continue to spread over a large number of disciplines and technologies. Research into water in all its aspects has become so diverse that even those with a direct interest find it impossible to keep up with the original literature beyond a very limited range. On the other hand, scientists want to keep in touch with a wide spectrum of basic and applied research on water and the role played by aqueous solvents in physical, chemical, biological, technological and environmental processes. Water Science Reviews contains three or four critical reviews of the type previously published in the seven volume work Water - A Comprehensive Treatise. Some reviews update previously published topics, while others feature areas of Water Sciences that have never yet been reviewed. A common focus is the central position adopted by water in the systems and processes described.

First published in 1985, this book covers the physiological and environmental factors that regulate leaf growth. It opens with a consideration of the importance to the plant of leaf size, form and development, and then divides naturally into two sections: the first covers the intrinsic factors within the leaf that influence development, including solute and hormonal status, cellular components, and energy transducing systems; the second considers the role of some major environmental variables in the regulation of leaf growth, including temperature, light, water and nutrients, atmospheric influences and the interactive effects of climatic variables.