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.

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 period following the second world war has witnessed an expanding commitment to incr~ased food production in tropical countries. Public and private initiatives at the national and international levels have led to the creation of programs geared specifically towards the improvement of food crops in tropical conditions. Examples of this increased commitment are the network of international agricultural research centers and numerous bilateral aid projects. As a consequence, crop improvement has become a truly worldwide endeavor, relying on an international network of institutions and collaborators. This holds also for Phaseolus beans. Following the discovery of the Americas, Phaseolus beans became distributed on all six continents. Yet, until not so long ago, most of the research on Phaseolus improvement took place in developed countries. In recognition of the nutritional importance of Phaseolus beans in developing countries, this has changed considerably in the last years, principally perhaps through the activities of the Centro Internacional de Agricultura Tropical (CIAT) and the International Board for Plant Genetic Resources (IBPGR). Consequently, the scope of the research on Phaseolus has broadened considerably and the number of Phaseolus researchers is larger than ever before.

The present volume "Excitation Energy and Electron Transfer in Pho. tosynthesis" is dedicated to a colleague and dear friend Warren L. But ler. I first met Warren when he visited the University of Illinois at Ur bana during the early sixties; he left an indelible impression on me as a person with warmth and enthusiasm. Initially, he was someone I looked to for guidance, but later we also became friends. Whenever I passed through Los Angeles, I always telephoned Warren and often end ed up taking a plane to San Diego to stay with two wonderful people, Warren and his wife Lila. His invitations could never be refused. Below I reproduce the words of Herbert Stern on Warren L. Butler's life; these words express my sentiments as well as those of many of Warren's friends: ''A lifetime of acedemic creativity criss-crossed by streaks of highbrow and lowbrow fun. There is no summary to this adventure be cause we can neither make nor proclaim an end. Warren has bequeathed us his garden of academic treasures. It is ours to keep and tend. There is lots of joy in our many recollections of Warren's life and sorrow's foil can only brighten the brightness that the joy radiates."

Plant hormone research is the favorite topic of physiologists. Past three decades have witnessed that this subject has received much attention. The inquisitive nature of human mind has pumped much in literature on this subject and this volume is the product of such minds. In the following pages various hormonal-controlled physiological processes like, flowering, seed dormancy and germination, enzyme secretion, senes cence, ion transport, fruit ripening, root growth and development, thig momorphogenesis and tendril thigmonasty have been included. The volume also contains a review paper on 'Growth Regulating Activity of Penicillin in Higher Plants' and has been presented for the first time. The vast contents of each review paper have been written by erudite scholars who have admirably carried out their evangelic task to make the text up TO date. This volume, I am sure, would stimulate the appetite of researchers of peripheral disciplines of botany and agricultural sciences and they will continue to enjoy the fun and adventures of plant hormone research. Save one. my most outstanding debts are due to the rich array of the contributors and other plant physiologists specially to Prof. Thomas Gaspar (Belgium), Prof. E. E. Goldschmidt (Isreal), Prof. H. Greppin (Switzerland), Dr. K. Gurumurti (India), Prof. M. A. Hall (U. K. ), Prof. H. Harada (Japan), Dr. M. Kaminek (Czechoslovakia), Dr. J. L. Karm oker (BangIa Desh), Prof. Peter B. Kaufman (U. S. A. ), Dr. V. I. Kefeli . / (U. S. S. R. ), Dr. M. Kutaoek (Czechoslovakia), Prof. S."

All measurements of intact leaf 02 sensitivity can be explained by the oxygenation model for glycolate formation and glycolate metabolism by established pathways. Predicting the rate of oxygenation from the underlying biochemistry is more reliable than calculating the rate of oxygenation from intact leaf gas exchange measurements. REFERENCES 1. Badger MR, TD Sharkey, S von Caemmerer: The relationship between steady-state gas exchange of bean leaves and the levels of carbon reduction cycle intermediates. Planta 160:305-313, 1984. 2. Bowes, G, WL Ogren, RH Hageman: Phosphoglycolate production catalyzed by ribulose diphosphate carboxylase. Biochem. Biophys. Res. Commun. 45:716-722, 1971. 3. Farquhar GD, S von Caemmerer, JA Berry: A biochemical model of photosynthetic C02 assimilation in leaves of C3 species. Planta 149: 78-90, 1980. 4. Farquhar GD, S von Caemmerer: Modelling of photosynthetic response to environmental conditions. In OL Lange, PS Nobel, CB Osmond, H Ziegler, eds, Encycl. of Plant Physiol., New Series, Springer Verlag, Heidelberg 12b: 549-587, 1982. 5. Jordan DB, WL Ogren: The C02/02 specificity of ribulose 1- bisphosphate carboxylase/oxygenase. Dependence on ribulose bisphosphate concentration, pH and temperature. Planta 161: 308-313, 1984. 6. Ku SB, GE Edwards: Oxygen inhibition of photosynthesis. I. Temperature dependence and relation to 02/C02 solubility ratio. Plant Physiol 59: 986-990, 1977. 7. Laing WA, WL Ogren, RL Hageman: Regulation of soybean net photosynthetic C02 fixation by the interaction of C02' 02 and ribulose l,5-diphosphate carboxylase. Plant Physiol 54: 678-685, 1974."

Forty years ago, when PLANT AND SOIL first appeared, Europe was still recovering from the devastating effects of World War II. During the war years, work in many centres of agricultural research had come to a virtual standstill. Buildings and equipment were destroyed, scientists were often forced to terminate their research and teaching activities and funds allocated to such work were diverted to other, at that time, more pressing needs. During the first post-war years reconstruction was undertaken with great zeal and in that light the founding of the new journal PLANT AND SOIL must be viewed. In the pre-war period most agricultural science journals were still primarily national ones and consequently many articles were published in languages mastered by only a limited number of potential readers. In small countries whose languages are not widely understood, the desire arose to publish research findings in one of the major languages. It is therefore understandable that in the early years of the journal's existence, large portions of PLANT AND SOIL were filled with articles from the Scandinavian countries and The Nether lands. Originally, rather frequent use was made of the opportunity to publish also in German and French, but with the advance of English as a major language of communication, a decline was noticeable in the number of German and French manuscripts submitted. As a consequence the Edi torial Board has recently decided to terminate the publishing of articles in these languages."

Thi s book is a general introduction into in vivo chlorophyll fluorescence and contains the contributions of the first International Ch 1 orophyll Fluorescence Sympos i urn he 1 din the Phys i kzentrum Bad Honnef, F. R. G. from June 6 to 8, 1988. This Symposium was made possible by a generous support from the Wilhelm and Else Heraeus Foundation, Hanau, which is gratefully acknmvledged. The book not only comprises all aspects of the applications of chlorophyll fluorescence in photosynthesis, stress physiol ogy, hydrobiology and remote sensing, but also gives access to measuring techni ques, data acqui si ti on and earl i er 1 iterature references. Thus it is far more than just a common proceedings book, it is a general introduction to all forms of application of the non-destructive in vivo chlorophyll fluorescence including the newest results. In a first chapter the inverse correlation between in vivo chlorophyll fl uorescence and photosynthet i c quantum convers i on and CO? -ass i mi 1 at ion is outlined, the origin and life-time of the chlorophyll fluOrescence at room and liquid nitrogen temperatures are given as well as the induction kinetics (Kautsky effect) and the methodo 1 ogi ca 1 approaches to regi ster different forms of chlorophyll-fluorescence signatures."

These volumes contain an excellent, up-to-date review of the rapidly developing field of photosynthesis research. They comprise the proceedings of the Ninth International Congress on Photosynthesis, held in Nagoya, Japan, in 1992, which was the first in the series to be held in Asia. The Congress was attended by over 1000 active participants from 43 countries, who contributed plenary lectures, symposium talks, posters and discussions. The volumes contain most of these contributions, in the form of review papers and short communications, assembled in 26 chapters, which cover a wide variety of subjects, such as: fundamental aspects, excitation energy transfer, primary reactions, bioenergetic processes, carbon metabolism, and its metabolic and genetic regulations; applied aspects, herbicides and artificial photosynthesis, and environmental aspects, photosynthesis under stress conditions and global climate change. Research in Photosynthesis is therefore an important document, containing the latest high-level information about photosynthesis in its broadest sense. The four volumes are a valuable reference source. Furthermore, the volumes are important for background study for those enetering this exciting and promising field of investigation.

The Second International Congress on Photosynthesis Research took place in Stresa, Italy during June 24-29, 1971; two centuries after the discovery of Photosynthesis by Joseph Priestley in 1971. This important anniversary was celebrated at the Congress by a learned account of Priestley's life and fundamental discoveries given by Professor Robin HILL, F. R. S. Professor HILL's lecture opens the first of the three volumes which contains the contributions presented at the Congress. The manuscripts have been distributed into three volumes. Volume I con tains contributions in the areas of primary reactions and electron transport; Volume II ion transport and photophosphorylation, and Volume III carbon assimilation, regulatory phenomena, developmental aspects, and from the two special sessions of the Congress devoted to evolution and photorespiration. It is realized that this division is necessarily somewhat arbitrary since many contributions relate to more than one of the above mentioned titles. However, the large number of contributions (over 3000 typed pages) made it impossible to publish the proceedings in less than three volumes. The printing of these volumes and the organization of the Congress were made possible by a contribution from the Consigio Nazionale delle Ricerche of Italy. The generous support of the Istituto Lombardo Acca demia di Scienze e Lettere to the publication of these proceedings is gratefully acknowledged. The editors wish to express their appreciation to all the scientists who contributed the results of the investigations, for their coopera tion; and to Drs."

For centuries biologists have been extremely interested in the structure of desert plants as examples of natural selection to harsh environmental conditions. Indeed, desert plants are frequently used as examples in many biology classes and textbooks to illustrate natural selection, but this has led to an unfortunate litany of errors and misconceptions about desert plant adaptations.
This new synthesis focuses on plants of lowland tropical and subtropical arid deserts. Readers will be surprised to discover that many features commonly ascribed to desert plants are rareley observed in the most common species. Instead, the typical structural adaptations of nonsucculent warm desert plants are now viewed as ways to maximize photosynthetic rate.

The Annual Beltsville Symposium provides a forum for interaction among scientists involved in research that is vitally important to agri culture and to the agricultural sciences. The Twelfth Symposium in this series focused on the unifying biochemical and physiological mechan isms controlling growth and development of biological systems - ani mals, plants insects. Unraveling the complex biochemical mechanisms associated with the sequencing of organism growth and development and identifying, locating, and manipulating key control mechanisms are essential in utilizing the full potential of biotechnology for improving the composition and quality of agricultural products and the profitability of agriculture. Accordingly, speakers directed their remarks to basic aspects of biological mechanisms in their area of specialization with considera tion given to current status, future direction, potential impact, and limitations to progress. The Symposium addressed fundamental questions in: -Tissue specific gene regulation: cell division and differentiation -Mechanisms for regulating hormone concentration -Hormonal regulation of growth and development -Non-hormonal regulation of growth and development -Nutritional regulation of growth and development Because the backgrounds of the symposium attendees covered a wide spectrum in the basic biological and physical sciences, each topic was introduced by a brief overview, but general reviews were avoided in favor of findings from on-going research projects. The symposium brought together a distinguished group of invited scientists from around the world who are leaders. Many attendees made poster presentations which increased the exchange of ideas and sti mulated informal discussion."

A recent volume of this series (Signals and Signal Transduction Pathways in Plants (K. Palme, ed.) Plant Molecular Biology 26, 1237-1679) described the relay races by which signals are transported in plants from the sites of stimuli to the gene expression machinery of the cell. Part of this machinery, the transcription apparatus, has been well studied in the last two decades, and many important mechanisms controlling gene expression at the transcriptional level have been elucidated. However, control of gene expression is by no means complete once the RNA has been produced. Important regulatory devices determine the maturation and usage of mRNA and the fate of its translation product. Post-transcriptional regulation is especially important for generating a fast response to environmental and intracellular signals. This book summarizes recent progress in the area of post-transcriptional regulation of gene expression in plants. 18 chapters of the book address problems of RNA processing and stability, regulation of translation, protein folding and degradation, as well as intracellular and cell-to-cell transport of proteins and nucleic acids. Several chapters are devoted to the processes taking place in plant organelles.

Taking readers out of the laboratory and into the humid tropical forests, this comprehensive volume explores the most recent advances occurring in tropical plant ecophysiology. Drawing on the knowledge of leading practitioners in the field, this book synthesizes a broad range of information on the ways in which tropical plants adapt to their environment and demonstrate unique physiological processes. This book is arranged into four sections which cover resource acquisition, species interactions, ecophysiological patterns within and among tropical forest communities, and the ecophysiology of forest regeneration. These sections describe plant function in relation to ecology across a wide spectrum of tropical forest species and growth forms. How do different species harvest and utilize resources from heterogeneous tropical environments? How do patterns of functional diversity reflect the overwhelming taxonomic and morphological diversity of tropical forest plants? Such fundamental questions are examined in rich detail. To illuminate the discussions further, every chapter in this book features an agenda for future research, extensive cross referencing, timely references, and the integration of ecophysiology and the demography of tropical species where the data exist. Tropical Forest Plant Ecophysiology provides plant scientists, botanists, researchers, and graduate students with important insights into the behavior of tropical plants. Biologists and foresters interested in tropical ecology and plant physiological ecologists will also benefit from this authoritative and timely resource.

The importance of mycorrhiza for the improvement of plant growth is increasingly being realised in Agriculture and Forestry and several mycorrhizal fungi have been commercially recognised for the purpose. The aim of this book is to describe the various techniques used to study the mycorrhizal biology. Problems with preparing such a book are many. Mainly mailing of manuscripts to and from authors resulted in irregular and final editing. Every effort was made not to change the peer review original manuscript to ensure accuracy. Our sole aims is to communicate to the greatest extent possible a current world need in mycorrhizal research. Plant productivity is regulated by microbial associations established in the plant root systems. The interactions of microorganisms and plant roots are especially important in providing nutritional requirements of the plant and the associated microorganisms. Plant growth and development are controlled largely by the soil environment in the root region -rhizosphere. This is a very complex environment in which the effects of the plant on soil microorganisms and the effects of microorganisms on the plant are interacting, interdependent and highly complex. Plant root exudates and breakdown products feed the microbes and the microbe in tum often benefit the plant. Mycorrhizal fungi are important tools for increasing growth, development and yield of economically important plants, they play important role of biofertilizer which can help establish plants in nutrient deficient soils, particularly phosphorus deficient soils, arid, semi-arid and waste lands.

China was the first country to use cytoplasmic male sterility to develop hybrid rice for commercial use in 1973. In 1986 more than 8 million hectares of hybrid rice were planted in China, which is one fourth of the total rice area and produces one third of the total rice in the country. Hybrids usually out yield the leading commercial varieties by -20-30%, giving an average yield advantage of 1 to 1. 5 t/ha, because of their better morphological traits, higher physiological efficiency, better resistance to major diseases and insects, and wide adaptability to various agro-ecological stresses. IMPROVEMENT OF HYBRID RICE A. Mutation techniques Almost all of the cultivated F1 rice hybrids in China are developed from cytoplasmic male sterile and restorer lines. According to surveys made in recent years, more than 30 sources of cytoplasmic male sterility in rice can be identified, among which only six are being commercially used (Table 1). Wild rice with aborted pollen (WA) cytosterility system is the most popular one in use to develop male sterile lines (MS line) in China. The main technique available for developing stable MS lines is sUbstitution backcrossing of the genome of one species into alien cytoplasm of another. Sufficient backcrosses are required to eliminate all nuclear genes derived from the cytoplasm donor species. A number of studies have shown that using interspecies crosses, such as the cross of wild rice (Q. perennis, Q. sativa, f.

The Conference on Tropical Rainforest Research: Current Issues was organised by the University of Brunei Darussalam and The Royal Geographical Society, London, and held in Bandar Seri Begawan, Brunei Darussalam, over 8 days in April 1993. Over 160 participants from 22 countries attended the Conference, which was opened on the 9th April by the Brunei Darussalam Minister for Home Affairs, Yang Berhormat Pehin Orang Kaya Laila Setia Bakti Diraja Dato Laila Utama Haji Awang Isa bin Datu Perdana Menteri Dato Laila Utama Haji Awang Ibrahim. The conference was initially intended to provide a forum to present the results of the expedition into the lowland mixed dipterocarp forest of the Temburong District of Brunei Darussalam, which had been jointly organised by the University of Brunei Darussalam and The Royal Geographical Society, London. The 15-month expedition, lasting from January 1991 to March 1992, was based at the then newly-completed Kuala Belalong Field Studies Centre, a research and education facility set up by the University with funds provided by the Brunei Government and Brunei-Shell Petroleum Sdn Bhd. The expedition, with over 70 scientists taking part, received financial support from a wide range of sponsors and Corporate Patrons, including Royal Brunei Airlines, the Baring Foundation, Daiwa-Dicam, Greencard Trust, the Hongkong Bank, Morgan Grenfell and Nomura-Nimco. The conference itself was supported by donations from Brunei-Shell Sdn Bhd, Royal Brunei Airlines and Standard Chartered Bank.

Electrical Manipulation of Cells provides an authoritative and up-to-date review of the field, covering all the major techniques in a single source. The book features broad coverage that ranges from the mechanisms of action of external electrical fields on biological material to the ways in which electrical stimuli are employed to manipulate cells. Bringing together the work of leading international authorities, the book covers membrane breakdown, gene delivery, electroporation, electrostimulation, cell movement, hybridoma production, plant protoplasts, electrorotation and stimulation, and electromagnetic stimulation. For each topic, the authors discuss the relevance of the approach to the current state of the art of biotechnology. Electrical Manipulation of Cells is an unmatched source of information for anyone involved in the manipulation of cells, particularly biotechnologists, cell biology, microbiologists, biophysicists and plant scientists. For researchers, the book provides technical material that ccan be employed in their own work. Students will gain thorough appreciation of the applications of this important technique.

This volume presents the proceedings of the Second International Sym posium on Genetic Aspects ofPlant Minerai Nutrition, held in Madison, Wisconsin in 1985. The mechanisms by which plants acquire, transport and utilize essential minerai nutrients are highly complex. The means by which plants either exclude or tolerate ions of metals toxic to plants are equally complex. The first symposium attempted to convene research scientists con cerned with minerai nutrition for the purpose of exploring the kinds of minerai nutrition phenomena identified as being under genetic contro!. The first symposium also placed much emphasis on research to which genetic intervention might be applied. At the second symposium more papers were presented on genetic and breeding research, a long-term objective of the first symposium. The second symposium also included biotic interactions under genetic con trol that either enhanced or impeded ion uptake, e.g. mycorrhizae and nitrogen fixing bacteria. This continuing dialogue is essential for a research area the complexity of which is due to its interdisciplinary nature.

This volume contains the papers, presented during a conference, organized jointly by the "Opzoekingsstation van Gorsem" and the "Limburgs Universitair Centrum", Belgium from 22 to 27 August 1982. For this third meeting, the chosen topic was the effect of different stresses on photosynthesis. Most of the research in this field is realized on water stress and temperature stress; this situation is refllected in the conference programme. However, the imp- tance of the other factors such as light, CO , salinity, anaerobiosis, was 2 also emphasized especially during the important discussion sessions. We express our gratitude to Drs. J. Gale, P. Jarvis, G.H. Krause, P.E. Kriedemann and P.S. Nobel for their excellent leadership during the discussion sessions. Particular thanks are also due to Dr. H.~i. Woolhouse who gave us an excellent inaugural address and whose erudition largely contributed to the interest of the discussions. For the first time in our experience of editors, we decided to use camera ready copies in order to publish more rapidly the proceedings and at a lower price. For a lot of reasons (among other things the bad choice of type of letter to be used and the choice of instructions to authors which were not perfectly followed by the authors), the technical presentation of this book will appear as non homogeneous; we accepted this lack of homogeneity with the hope tbat the publication time would be shorter in spite of the fact that, some authors delivered their manuscript with delay.

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.""

Fertilizer is a vital component of strategies for expanding foodproduction. The rapid growth in population and the widening food deficits inmany tropical countries of Asia, Africa, and Latin America call attention to those aspects of fertilization that have been neglected but are expected to yield large economic payoffs in the future. Fertilizer sulfur falls into this category. In the past fertilizer sulfur received little attention from researchers and policymakers since sulfur deficiency was not considered a serious problem. It was not a problem because of low crop yields, extensive cropping, and the incidental supply of sulfur through rain, irrigation water, manures, and sulfurcontaining fertilizers. However, the situation has changed in the last three decades. Moder nagriculture based on high crop yields, intensive cropping, improved crop varieties, and greater use of sulfur-free fertilizers and environmental regula tions restricting sulfur emissions are creating large gaps between sulfur sup ply and sulfur requirements. Sulfur deficiencies are widespread and grow ing. Consequently, the full potential of a modern agricultural system in tropical countries is not being realized. This research effort results from the recognition of the seriousness of the sulfur problem and its adverse impact on food production as well as IFDC's dedication to the development and transfer of economically ef ficient fertilizer technology to tropical countries. This study represents a comprehensive analysis of the technical and economic linkages between fer tilizer sulfur and food production, and it provides guidelines for future directions in fertilizer sulfur research and public policy."

With the demonstration of the "triple response" in plants by Neljubow at the turn of the century, ethylene has been identified as a substance specifically affecting plant growth. Yet it took a few more decades to show that ethylene is a naturally occurring product of plants having all the characteristics of a phytohormone. Ever since much effort has been devoted to a wide variety of physiological and biochemical problems relevant to ethylene. A first meeting was organized in Israel in 1984 to bring together many people active in this rapidly expanding field of experimental research. It is the aim of the present symposium to provide once more a forum at which researchers might expose and comment progress in their work over the last few years. Speakers were invi ted and their contri buti ons ordered ina number of sessions, each of which was centered on a particular topiC. Much of the benefit came from ensuing discussion sessions which were conducted with much competence and expertise by Anderson, Ben-Arie, Goren, Morgan and Osborne. All of these colleagues are recognized leaders in ethylene research today and the organizers owe a very special gratitude to them for their substantial contribution to the programme. It is well to remember the friendly atmosphere, so essential to the success of the whole meeting and so much enjoyed by every partiCipant. Prompt publi ca tion of the papers was made possi ble by the camera-ready procedure offered by the publisher.