Cyanobacterial symbioses are no longer regarded as mere oddities but as important components of the biosphere, occurring both in terrestrial and aquatic habitats worldwide. It is becoming apparent that they can enter into symbiosis with a wider variety of organisms than hitherto known, and there are many more still to be discovered, particularly in marine environments. The chapters cover cyanobacterial symbioses with plants (algae, bryophytes, Azolla, cycads, Gunnera), cyanobacterial symbioses in marine environments, lichens, Nostoc-Geosiphon (a fungus closely related to arbuscular mycorrhiza fungi) symbiosis, and artificial associations of cyanobacteria with economically important plants. In addition, cyanobiont diversity, sensing-signalling, and evolutionary aspects of the symbiosis are dealt with. Renowned experts actively involved in research on cyanobacterial symbioses deal with ecological, physiological, biochemical, molecular, and applied aspects of all known cyanobacterial symbioses.
This volume on cyanobacteria in symbiosis complements the two earlier volumes on cyanobacteria published by Kluwer (Molecular Biology of Cyanobacteria, edited by D.A. Bryant and Ecology of Cyanobacteria, edited by B.A. Whitton and M. Potts). Together, the three volumes provide the most comprehensive treatment of cyanobacterial literature as a whole. The book will serve as a valuable reference work and text for teaching and research in the field of plant-microbe interactions and nitrogen fixation.

Sixty years ago at the Waite Agricultural Research Institute, G. Samuel, a plant pathologist, and C. S. Piper, a chemist, published their conclusion that the cause of roadside take-all, a disease of oats, was manganese deficiency. This report, together with the concurrent and independent studies of W. M. Carne in Western Australia were the first records of manganese deficiency in Australia and came only six years after McHargue's paper which is generally accepted as the final proof of the essentiality of this element. There must have been a few doubts for some people at the time, however, as the CAB publication, 'The Minor Elements of the Soil' (1940) expressed the view that further evidence to this effect was provided by Samuel and Piper. Their historic contributions are recognised by the International Symposium on Manganese in Soils and Plants as it meets on the site of their early labours to celebrate the 60th anniversary. This year Australians also acknowledge 200 years of European settlement in this country and so the Symposium is both a Bicentennial and a diamond jubilee event which recognises the impact of trace elements on agricultural development in Australia. In a broader sense, a symposium such as this celebrates, as it reviews, the efforts of all who over the ages have contributed to our knowledge of manganese in soils and plants.

Water is essential for life and without water no life exists. The liquid sur- rounding of an aqueous solution is the conditio sine qua non for most of the physiological responses and as such, water is as decisive for the occurrence of a single enzymatic reaction as it is for the global zonation of world vegetation. It is no wonder that scientists since early times have made every effort to describe and understand the functional interrelationships between water and the phe- nomenon of life. During the past half of this century, these endeavours in the field of botany have been marked by steps which might be symbolized by a series of books such as "The plant in relation to water" (1. Maximov, 1929), and "Die Hydratur der Pflanze in ihrer physiologisch-6kologischen Bedeutung" (H. Walter, 1931), then "Pflanze und Wasser" (Vol. III of the Encyclopedia of Plant Physiology, edited by O. Stocker, 1956), and "Plant-water relations" (R. O. Slatyer, 1967), or the treatment of "Displacement of water and its control of biochemical reactions" (S. Levin. 1974).

Biological fixation of nitrogen by organisms and associations other than those concerned in the legume-Rhizobium symbiosis has attracted increasing attention since the firstintemationalworkshop on the theme at Piracicaba, Brasil, in 1979. Approximately 150 scientists gathered on September 2-8, 1984, at the Hanasaari Cultural Centre near Helsinki, Finland, for the third international meeting on nitrogen fixation with non-legumes. Forty-two papers and 39 posters were presented; 32 of the papers have been broughttogetherin this publication. The Symposium was generously sponsored by the FinnishNational Fund for Research and Development (SITRA) in connection with a large project on biological nitrogenfixation and utilization ofnitrogen extending from 1980 to 1985. The Symposium was organized jointly by SITRA, which dealt with all practical matters very efficiently and with impressive concern for the welfare of the participants, and Societas Biochemica, Biophysica et Microbiologica Fenniae, the society of Finnish microbiologists, which made valuable contributions on scientific matters. As in the previous symposium at Banff, Canada, in 1982 the programme did not involve parallel sessions~ all participants had the opportunity of listening to all presentations. Consequently, the FIN- NIF Symposium profited from a steady audience and the consistency this gave to the discussions. In view of the growing interest in N-fixation with non-legumes and the continuous broadening of the field, such an arrangement may not be possible in the future. I thank all participants for their contributionsto both oral sessions and poster presentations, and hope that this publication will become a frequently quoted source of knowledge.

Every year between three and four hundred papers are published on the topic of insulin action. This extraordinary publication rate prevents any author from includ ing an exhaustive bibliography in any review or book. Perhaps due to this there is no single text that attempts to cover the effects and the mechanism of action of insulin. This book is such an attempt. I intend to present a review of the physiological effects of insulin, the pathology of defects in the action of insulin, and the current views on the mechanism of action of this hormone. I make no apology for the fact that the bibliography will not be extensive and that the amount of experimental detail and data discussed will be kept to a relevant minimum. This book is not intended for the expert in the field, but for the second- or third-year undergraduate and graduate student of medicine, biochemistry, physiology or related disciplines, and will be valuable as a reference source for research workers. The book is presented as a guide, a summary of the ideas and facts; it will present a reader with a foretaste of a fascinating and ever-changing field. I have attempted to be up-to-date with published research work. Any significant contributions to the field not included in the first draft have been added as footnotes. I assume a basic knowledge of the metabolic pathways of carbohydrates, fats and proteins."

The originality of this volume is to reveal to the reader the fascination of some unfamiliar sensory organs that are sometimes ignored and often misunderstood. These receptors have only recently been identified and their functional specificity is in some cases still a matter for discussion. The four classes of sensory organs considered here differ widely from one another in many respects. One might even say that the only thing they have in common is that they belong to cold-blooded vertebrates. These classes are: 1. the directionally sensitive lateral-line mechanoreceptors of fishes and amphi bians (Chapter 7); 2. the pseudobranchial organs of some teleosts, equipped with pressoreceptors and at least three other types of receptors (osmo- and chemoreceptors) (Chapter 8); 3. the infrared-sensitive pit organs of some snake families (Chapter 9); 4. the various kinds of electroreceptors found in several marine and freshwater fish families (Chapters 2 to 6). The first three classes of receptors mentioned above thus rate only one chapter each, whereas five chapters are devoted to the electroreceptors. Electroreception has aroused enormous interest among physiologists in specialties ranging from molecular biology to animal behavior. The resulting quantity of research and discussion fully justifies this disproportion. However, it cannot be denied that the contents of the volume must appear unbalanced and heterogeneous, yet it should not be perceived as a mere juxtaposition of particular and unrelated cases."

The plasma membrane is at once the window through which the cell senses the environment and the portal through which the environment influences the structure and activities of the cell. Its importance in cellular physiology can thus hardly be overestimated, since constant flow of materials between cell and environment is essential to the well-being of any biological system. The nature of the materials mov ing into the cell is also critical, since some substances are required for maintenance and growth, while others, because of their toxicity, must either be rigorously excluded or permitted to enter only after chemical alteration. Such alteration frequently permits the compounds to be sequestered in special cellular compartments having different types of membranes. This type of homogeneity, plus the fact that the wear and tear of transmembrane molecular traffic compels the system to be constantly monitored and repaired, means that the membrane system of any organism must be both structurally complex and dy namic. Membranes have been traditionally difficult to study because of their fragility and small diameter. In the last several decades, however, remarkable advances have been made because of techniques permit ting the bulk isolation of membranes from homogenized cells. From such isolated membranes have come detailed physical and chemical analyses that have given us a detailed working model of membrane. We now can make intelligent guesses about the structural and func tional interactions of membrane lipids, phospholipids, proteins, sterols and water."

Proceedings of the NATO Advanced Study Institute, Pugnochiuso, Italy, June 22-July 3, 1986

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.

The problems associated with the movement of water and solutes throughout the plant body have intrigued students of plants since Malpighi's conclusions in 1675 and 1679 that nutrient sap flows upward and downward in stems through vessels in both wood and bark. Steven Hale's ingenious experiments on the movement of water in plants in 1726 and Hartig's observations of sieve-tube exudation in the mid-19th century set the stage for continued intensive studies on long-range transport in plants. In spite of this interest for more than 200 years in the movement of solutes and water in plants, it has only been within the last 20 to 30 years that extensive research effort has been directed toward a critical evaluation of the interactions among the various cellular organelles. The important roles played by the exchange of metabolites in the control and regulation of cellular processes is now widely recognized, but in most instances poorly understood.

As editor of the two-part Volume V on photosynthesis in RUHLAND'S Encyclopedia, the forerunner of this series published in 1960, I have been approached by the editors of the present volume to provide a short preface. The justification for following this suggestion lies in the great changes which have been taking place in biology in the two decades between these publications, changes which are reflected in the new editorial plan. Twenty years ago it appeared convenient and formally easy to consider photo synthesis as a clearly separated field of research, which could be dealt with under two major headings: one presenting primarily photochemical and biochemical prin ciples, the other physiological and environmental studies. Such a partition, however, as far as aims and opinions of the authors were concerned, resulted in a rather heterogeneous volume. Today, the tendency in experimental biology is towards a merger of previously distinct disciplines. Biochemists and biophysicists have developed their methods to such an extent that, over and above the analysis of individual reaction sequences, work on the manifold interrelationships among cellular activities has become in creasingly possible. Joining them in growing numbers are the physiologists and ecologists with their wealth of information on activity changes in vivo and on the variability and efficiency of the organisms concerned. Furthermore, biochemists, biophysicists and physiologists also now share a lively interest in ultrastructure research, the results and implications of which, through continually improving methodology, have generated important stimuli for the work in the field of cell function."

This book results from a symposium on the theme of 'The Physiology and Biochemistry of Plant Productivity' which was held at the University of Calgary from July 14-18, 1980, and was jointly sponsored by the Canadian Society of Plant Physiologists and the International Association of Plant Physiologists. The subject matter of the book deals with various aspects of nitrogen and carbon metabolism, their interrelationships and interdependence. The topics covered in the chapters highlight various interesting and important lines of research that are in progress. There is no attempt to provide a comprehensive coverage of the basic physiological knowledge upon which this research depend- important references are to be found at the end of each chapter, however, and the reader will be able to pursue these as necessary. An introductory chapter by Dr. R.G.S. Bidwell (winner of the C.S.P.P. Gold Medal in 1979) considers some implications of plant physiological research and the aims and responsibilities of plant physiologists. In the next two chapters Drs. J. Rigaud and L.E. Schrader (with R.J. Thomas) elaborate on current research on nitrate metabolism and nitrogen fixation, and how an understanding of these phenomena might be usefully applied towards the manipulation of plants to improve productivity. Dr. J.S.

Oxygen (O ) appeared in significant amounts in the Earth's atmosphere over 2. 2 2 billion years ago, largely due to the evolution of photosynthesis by cyanobacteria (Halliwell 2006). The O molecule is a free radical, as it has two impaired electrons 2 that have the same spin quantum number. This spin restriction makes O prefer to 2 accept its electrons one at a time, leading to the generation of the so-called reactive oxygen species (ROS). The chemical nature of these species dictates that they can create damage in cells. This has contributed to the creation of the "oxidative stress" concept; in this view, ROS are unavoidable toxic products of O metabolism and 2 aerobic organisms have evolved antioxidant defences to protect against this tox- ity (Halliwell 1981; Fridovich 1998). Indeed, even in present-day plants, which are full of antioxidants, much of the protein synthetic activity of chloroplasts is used to replace oxidatively damaged D1 and other proteins (Halliwell 2006). Yet, the use of the "oxidative stress" term implies that ROS exert their effects through indiscriminate widespread inactivation of cellular functions. In this context, ROS must not be able to react with lipids, proteins or nucleic acids in order to avoid any damage to vital cellular components. However, genetic evidence has suggested that, in planta, purely physicoche- cal damage may be more limited than previously thought (Foyer and Noctor 2005).

The study of air pollution effects on vegetation has made rapid progress in the last five years. Growing concerns about effects of future increases in temperature and carbon dioxide (C0 ) levels on plant life have altered 2 the perspective of plant biologists in the field of pollutant-plant inter actions. In many cases, it is anticipated that crops and trees will increasingly experience multiple stresses in an altered environment: an environment in which physiological processes will no longer be matched to climate. Because of this problem, a major part of the focus of the air pollution effects research has shifted since 1987. Moreover, recent advances in our understanding of plant metabolic and molecular responses to stress have made it clear that many abiotic stresses elicit similar fundamental mechanisms. Adaptation responses to drought, extremes of temperature, xenobiotics and air pollutants are now known to involve the response of both specific and common resistance mechanisms, which often include altered gene expression. The field of air pollution effects on vegetation has benefitted greatly from this unification since results obtained and advances made in allied fields are now directly relevant. The advent of molecular genetics has made possible the production of transgenic plants containing altered amounts of resistance gene products which enables the posing of experimental questions which could not be addressed only five years ago. Hypotheses concerning the relevance of specific metabolites and processes to known responses to air pollution stress can now be tested."

There is a paucity of information on the dynamics of Ascorbic Acid (AA) turnover in relation to germination, metabolism, growth, differentiation and development of a plant and in those undergoing stress of various types. in presowing treatment of seeds etc. The turnover of AA plays an important role during the juvenile phase of growth of a plant and has a significant bearing on its subsequent growth, development and maturation. The beneficial effect of presowing treatment of seed with Ascorbic Acid (AA) + H2 O highlights the validity of the AA-nucleic acid 2 protein metabolism concept of growth and development of plan ts. During the course of the last 30 years, work has been undertaken by the author and his collaborators on the meta bolic drifts of regulatory substances during juvenile, vegetative, reproductive and senescent phases. The most important of these growth regulatory substances was found to be Ascorbic Acid. The dynamiC role of AA turnover is revealed by its control of rates of metabolic processes as well as those of enzymic reactions which paves the way to "New Genetics.""

This book gathers contributions presented during an In- ternational meeting organized by the Laboratory of Photobio- logy of the University of Liege, Belgium, on 8 and 9 August 1983. The general topic of the discussions was protochlorophyl- lide reduction and greening. Among the reasons for choosing this topic were the recent advances in the field. These ad- vances deal with: (1) The characterization of the basic constituents of the photoenzymatic complex responsible for protochlorophylli- de reduction. This complex is known to be ternary, comprising the pigment: protochlorophyllide, NADPH and the enzyme proto- chlorophyllide oxidoreductase. (2) The discovery of short-lived intermediates in the photoreduction process, and in particular, the recent findings resulting from the proqresses of the picosecond and nanosecond spectrometry. (3) The obtention of new data on the components of the plastids, on the changes they undergo during the first steps of greening, and on the distribution of the pigment-protein complexes between the various substructures of the etioplast. (4) The detection of early photoactivities apart from protochlorophyllide reduction. These subjects have ~cen extensively discussed during the meeting and several sections of this book are devoted to the presentation of the new data.

The idea of addressing the problem of the genetic specificity of mineral nutrition at an international level arose four years ago in a proposal for this topic to be included in the program of the II Congress of the Federation of European Societies for Plant Physiology (FESPP) as a separate section. The Organising Committee of the II Congress of FESPP which was held in Santiago de Compostella in 1980 arranged a special session and it was clearly successful. A special scientific meeting where the genetic aspects of plant nutrition in their widest sense could be presented and discussed comprehensively appeared to be necessary and that is how this Symposium came to be organized by the Serbian Academy of Sciences and Arts. Much progress has already been achieved in this field, and bearing in mind the importance of this problem, particularly at the present moment, it is necessary for us both to acquaint ourselves with what has been achieved so far, and even more to direct attention and effort to the fundamental problems for the future.

An International Symposium, Qiryat Anavim, Israel, January 9-12, 1984

Unlike the situation in the major cereals, the yields of Vicia faba have not been markedly increased during the last half century. There is no single cause for this but among those that have been important is the lack of cytogenetic understanding in relation to breeding performance. Since as a consequence, little genetic variation has been available to agronomists conclusions, probably unwarranted, have been drawn about the limited prospects for the faba bean. Against such a background it has been difficult to justify the investment of research resources in the crop. The central theme of this book is that with the establishment of cytogenetic studies in Vicia faba understanding of its genetic system will develop in relation to breeding improvement and thereafter some at least, of the impediments to yield increase can steadily though not dramatically, be removed. We have distinguished between longer and shorter papers and only the former include Abstracts. The latter amplify themes in the longer papers or were written to develop particular topics at the request of the editors. G.P. Chapman S.A. Tarawali Wye College, April, 1984 VIII ACKNOWLEDGEMENTS We would like to thank the various contributors to this publication for the readiness with which they have met our various req~ests. Our thanks are due to the staff of the Centre for European Agricultural Studies for facilitating arrangements for the Seminar and to Mr. Peter Abott and Carl Zeiss (Oberkochen) Ltd. for the display of microscopes.

The Annual Beltsville Symposium provides a forum for interaction among scientists involved in research that has vital impact on agriculture and on the agricultural sciences. The 10th Symposium in the series, Biotechnology for Solving Agricultural Problems, focuses on the use of a revolutionary new set of tools, biotechnology, and attempts to define the set in terms of its applications in agriculture. Biotechnology has already contributed to the genetic improvement of agricultural products. Procedures that were impossible to test or to implement in the past because of technological limitations are now routinely used by many scientists. Four areas that have benefitted from advances in biotechnology are covered in the symposium proceedings. These areas include genetic manipulation, nutrition, health and disease, and natural resource management. The 31 invited speakers have identified programs of basic and applied research on plants, animals, and insects that fall within these broad areas. Their research strategies included such techniques as germline modification, gene mapping, monoclonal antibody production, and gene transposition. These strategies have tapped new well springs of information and technologies ranging from the regulation of gene expression (and with it, the regulation of development, growth, disease resistance, and nutrient metabolism) to degradation of pesticides and toxic wastes. The applications of biotechnology to agricultural research have opened virgin vistas with enormous potential. The new biotechnological techniques and those that will evolve with their use will contribute markedly to the capacity of the agricultural sciences to advance the well-being of the human race.

The contributions of plant genetics to the production of higher yielding crops of superior quality are well documented. These successes have been realized through the application of plant breeding techniques to a diverse array of genetically controlled traits. Such highly effective breeding procedures will continue to be the primary method employed for the development of new crop cultivars; however, new techniques in cell and molecular biology will provide additional approaches for genetic modification. There has been considerable speculation recently concerning the potential impact of new techniques in cell and molecular biology on plant improvement. These genetic engineering techniques should offer unique opportunities to alter the genetic makeup of crops if applied to existing breeding procedures. Many questions must be answered in order to identify specific applications of these new technologies. This search for applications will require input from plant scientists working on various aspects of crop improvement. This volume is intended to assess the interrelationships between conventional plant breeding and genetic engineering.

Historically, scientists and laymen have regarded salinity as a hazar dous, detrimental phenomenon. This negative view was a principal reason for the lack of agricultural development of most arid and semi arid zones of the world where the major sources of water for biological production are saline. The late Hugo Boyko was probably the first scientist in recent times to challenge this commonly held, pessimistic view of salinity. His research in Israel indicated that many plants can be irrigated with saline water, even at seawater strength, if they are in sandy soil - a technique that could open much barren land to agriculture. This new, even radical, approach to salinity was clearly enunciated in the book he edited and most appropriately entitled 'Salinity and Aridity: New Approaches to Old Problems' (1966). A decade later, three members of the United States National Science Foundation (NSF), Lewis Mayfield, James Aller and Oskar Zaborsky, formulated the 'Biosaline Concept'; namely, that poor soils, high solar insolation and saline water, which prevail in arid lands, should be viewed as useful resources rather than as disadvantages, and that these resources can be used for non-traditional production of food, fuels and chemicals. The First International Workshop on Biosaline Research was con vened at Kiawah Island, South Carolina, in 1977 by A. San Pietro.

The last 10 years have witnessed an explosion in our understanding of plant h- mones. The often vague models of hormone action developedover decadeshave been replaced in short order by detailed molecular models that include receptors and in many cases downstream signal transduction components. Given the rapid progress in understanding the mechanism of action of plant growth regulators, a technical review of hormone methodology is timely. Our book focuses on genetic, biochemical, ana- tical and chemical biological approaches for understanding and dissecting plant h- mone action. The greatest strides in plant hormone biology have come, by and large, from the use of genetic methods to identify receptors and we dedicate a chapter to general genetic methods of analysis using the model system Arabidopsis thaliana. A cluster of chapters focuses on biochemical methods for documenting interactions betweenhormonesand their receptors. Theimportance of these assays is tremendous; receptor-ligand interactions in animal model systems have been the cornerstones of pharmacological and medicinal chemical assays that have enabled identification of selective and non-selective agonists and antagonists that can be used to further probe and dissect questions of receptor function. This is likely to be a major new frontier in plant hormone research.