Note Not long after publication of Orchid Biology, Reviews and Perspectives (OB) volume VII, my co-editor, Dr. Alec M. Pridgeon informed me that the pressure of other duties, especially the editing of Genera Orchidacearum (GO) will make it impossible for him to continue as co-editor and eventually editor ofthe series. Alec is an excellent orchid scientist and editor. I was sorry to that he had to leave OB, but glad that GO will be in his able hands. The first volume of GO attests to his considerable abilities and I wish him much success in the future. Editors of orchid publications are not the most common of species (to use a botanical analogy) and finding a replacement for Alec was not easy. However I was fortunate that Dr. Tiiu Kull agreed to become my co-editor and eventually take over the series. As is obvious from the Contributors section Dr. Kull has extensive experience as both writer and editor. My interactions with her while editing this volume have convinced me she is an excellent choice. Scientifically she brings to OB an appreciation and understanding of northern terrestrial orchids, a group, which has not received as much attention as it deserves. Another addition to OB is Dr. Tim Wing Yam who agreed to become an associate editor. Tim, who holds a position at the Singapore Botanic Gardens, will provide expertise on seed germination, hybridization, tissue culture, species and conservation.

The rise in the concentration of CO2 in the atmosphere since the start of industrialization, and the global warming associated with this greenhouse gas, has stimulated research into the response of plants to elevated levels of CO2. Much of this work has been carried out in controlled environments which provide limited information about long-term effects on vegetation. In contrast, CO2-emitting mineral springs provide a unique opportunity to consider vegetation which has endured over many generations at naturally elevated levels of CO2. This volume presents findings from a range of sites, confirming the potential of these natural laboratories in the investigation of this important aspect of climate change.

With one volume each year, this series keeps scientists and advanced students informed of the latest developments and results in all areas of the plant sciences. The present volume includes reviews on genetics, cell biology, physiology, comparative morphology, systematics, ecology, and vegetation science.

Nematode interactions are important biological phenomena and of great significance in agriculture. It is a fascinating subject which is multidisciplinary by nature, and concerns any scientist involved with plant health. There have been marked advances in our knowledge of various aspects of the subject in the last two decades. This study area has been the subject of several reviews, but there was no exclusive text on the subject. This has stressed the need to document the information, developing a unifying theme which treated nematode interactions in a holistic manner. This book is about the inter action of plant-parasitic nematodes with other plant pathogens or root symbionts, the nature of their associations, their impact on the host and con sequential interactive effects on the involved organisms. Since nematodes are at the centre of the theme, the responsibility of understanding of other plant pathogens dealt with in this book is largely delegated to the reader. I have limited the book content to interactions with biotic pathogens and root symbionts only, for various reasons. The book embodies 16 chapters, and attempts to present balanced infor mation on various aspects of nematode interactions with other plant pathogens and root symbionts. Some chapters describe general aspects of the subject. Interactions of nematodes with specific groups of organisms are addressed in the remaining chapters."

Photosynthetic plant cells are compartmentalized into subcellular organelles such as chloroplasts, mitochondria, peroxisomes, the cytosol, and the vacuole. Although this compartmentation serves to isolate particular functions to particular subcellular locations, the successful metabolic activity of the cell is actually dependent on a controlled and coordinated interaction between these organelles. In this book, leading scientists have contributed reviews of current research on the interaction of organelles in processes such as C3, C4, C3-C4 and CAM photosynthesis, photorespiration, substrate and protein transport, respiration, lipid metabolism, and organelle biogenesis. The result is a comprehensive state-of-the-art volume that provides a rich source of reference and information for plant biochemists and their students.

The activation of carbon dioxide by transition metal complexes has been extensively studied. both experimentally and theoretically. 1 Central reactions in this chemistry are the insertion of C02 into M-X bonds. where X = H. C. 0. and N. (eq. 1-4). We are presently investigating the mechanistic aspects of these reaction processes and will herein deSCribe our current level of understanding. Comparisons of the pathway of the carbon-carbon bond fonning process in transition metal chemistry with the well known analogous chemistry involving organolithium reagents will be presented. Furthermore. the role of these reaction types in both homogeneous and heterogenous catalytic processes leading to useful chemicals will be elaborated. _OM> (1) lMt-H + ~ lMlopi _OM> (2) [Mt-R + C0. 2 [M]0. 2CR _OM> (3) [Mt-OR+ ~ [M]0. 2COR _OM> (4) [Mt-NR2 + C0. 2 [M]~CNR2 Insertion of C02 into the Metal-Hydride Bond. The reaction of anionic group 6 (Cr. Mo. W) transition metal hydrides with carbon dioxide to afford metalloformates occurs readlly at ambient temperature and 2 reduced pressures of carbon dioxide. This insertion process is referred to the normal pathway (Scheme 1). There are no documented cases of C02 insertion into the metal hydride bond to provide the alternative. metallocarboxylic acid. isomer (referred in Scheme 1 as abnormal). 3 Recent theoretical studies ascribe this preference to an unfavorable electrostatic interaction and poorer orbital overlap in the latter pro 4 cess. Nevertheless.

The study of plant development in recent years has often been concerned with the effects of the environment and the possible involvement of growth substances. The prevalent belief that plant growth substances are crucial to plant development has tended to obscure rather than to clarify the underlying cellular mechanisms of development. The aim in this book is to try to focus on what is currently known, and what needs to be known, in order to explain plant development in terms that allow further experimentation at the cellular and molecular levels. We need to know where and at what level in the cell or organ the critical processes controlling development occur. Then, we will be better able to under stand how development is controlled by the genes, whether directly by the continual production of new gene transcripts or more indirectly by the genes merely defining self-regulating systems that then function autonomously. This book is not a survey of the whole of plant development but is meant to concentrate on the possible component cellular and molecular processes involved. Consequently, a basic knowledge of plant structure is assumed. The facts of plant morphogenesis can be obtained from the books listed in the General Reading section at the end of Chapter 1. Although references are not cited specifically in the text, the key references for each section are denoted by superscript numbers and listed in the Notes section at the end of each chapter."

The Second International Oat Conference. of which these are the proceedings.was heldat Aberystwyth. 15-18 July.1985. In thebusiness meeting heldatthecloseof theFirstInternational Oat Workshop that was held at PennsylvaniaStateUniversity in 1982. an Internat i ona1 Organsi i ng Committee under the chairmanship of Or KJ Frey was electedto organisethe next conference.and Aberystwyth was proposed and agreed as the venue. The final date of the Second Conferenceand the out 1i ne of the programme. inc1udi ng selection of the rnain speakers. was agreed by the Internat i ona1 Committee but 1oca1 arrangements and finalisation of the programme were delegatedto a local sub-committee centredat the Welsh Plant Breeding Station. We wish to record our appreciationof the work done bythis localcommittee in assuming various organisational responsibilities. From the outsettherewas a firm committmentto makethe Conferenceas international as possible and every effortwas made both to provide a programme thatwouldattract participants from allpartsof the worldand to keep costs to a minimum so as to increasethe chances of potential delegatesbeing ableto attend. Alistof participantsis includedbut it is worthyof notethattwenty-three countr ies were represented. The Conferencewas organisedintoseven half-daysessions. Six of these covered differenttopics relevantto the improvement of oats and the seventhwas a visit to the Welsh PlantBreedingStationwhere laboratory and fieldwork ontheoatcrop was demonstrated.

In 1971, the late Dr. J. Kolek of the Institute of Botany, Bratislava, organized the first International Symposium devoted exclusively to plant roots. At that time, perhaps only a few of the participants, gathered together in Tatranska Lomnica, sensed that a new era of root meetings was beginning. Nevertheless, it is now clear that Dr. Kolek's action, undertaken with his characteristic enormous enthusiasm, was rather pioneering, for it started a series a similar meetings. Moreover, what was rather exceptional at the time was the fact that the meeting was devoted to the functioning of just a single organ, the root. One possible reason for the unexpected success of the original, perhaps naive, idea of a Root Symposium might lie with the fact that plant roots have always been extremely popular as experimental material for cytologists, biochemists and physiologists whishing to probe processes as diverse as cell division and solute transport. Of course, the connection of roots with the rest of the plant is not forgotten either. This wide variety of disciplines is now coupled with the development of increasingly sophisticated experimental techniques to study some of these old problems. These factors undoubtedly contribute to the necessity of continuing the tradition of the root symposia. The common theme of root function gives, in addition, a certain unity to all these diverse activities.

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.

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.

This book provides a comprehensive and interactive view of recent advances in the cytology, anatomy, and physiology of roots as presented at the 5th International Symposium on Structure and Function of Roots, held on 31 August-4 September, 1998, in Stara Lesna, Slovakia. This edition differs from previous ones by including some aspects of functional genetics and plant morphogenesis. The book is intended to serve both students and researchers as a valuable source of updated information, ideas, and concepts dealing with the most fundamental questions of development and function of plant roots.

Research in animals and plants is frequently 'departmentalized' and funded according to Kingdoms by granting bodies. The use of transgenes to address biological questions in all Kingdoms led us to propose to the Royal Society that fundamental and strategic studies in animals and plants involving trans genes should be presented in one meeting, rather than, as so often happens, in different scientific societies. The two-day Discussion Meeting held inJuly 1992, and reported here provided insights into how trans genes are being exploited to discover new knowledge in animals and plants. The papers were presented by leading investigators in the biological sciences, and the book reflects an experiment in interdisciplinarity which was declared a successful venture by the large crowd of participants and delegates. The transgenic area is one of high scientific interest and sporadic, yet intense biotechnological euphoria. This is dramatically illustrated among the following papers which show how genetic maps of animals and plants produce new knowledge of disease incidence in humans, and how the design of transgenes can result in biodegradable plastic in higher plants, human pharmaceutical proteins in livestock, or bacterial proteins in cotton crops to protect against insect damage.

A growing interest has been shown recently in the dymanics of nitrogen in agricultural and natural ecosystems. This has been caused by increasing demands for food and fibre by a rapidly expanding world population, and by a growing concern that increased land clearing, cultivation and use of both fertilizer and biologically fixed nitrogen can have detrimental effects on the environment. These include effects on water quality, eutrophication of surface waters and changes in atmospheric composition all caused by increased cycling of nitrogenous compounds. The input and availability of nitrogen frequently affects the productivity of farming systems more than any other single management factor, but often the nitrogen is used inefficiently. Much of the fertilizer nitrogen applied to the soil is not utilised by the crop: it is lost either in solution form, by leaching of nitrate, or in gaseous forms as ammonia, nitrous oxide, nitric oxide or dinitrogen. The leached nitrate can contaminate rivers and ground waters, while the emitted ammonia can contaminate surface waters or combine with atmospheric sulfur dioxide to form aerosols which affect visibility, health and climate. There is also concern that increased evolution of nitrous oxide will deplete the protective ozone layer of the stratosphere. The possibility of a link between the intensity of agricultural use of nitrogen, nitrous oxide emissions and amounts of stratospheric ozone has focussed attention on these interactions.

Several fundamental advances were announced at the Seventh International Symposium on Molecular Plant--Microbe Interactions held in Edinburgh in 1994. These included the cloning and identification of plant resistance genes involved in recognition of pathogens; the description of genetically engineered plants with novel resistance to pathogens; characterization of the molecular basis of pathogenicity of fungal and bacterial plant pathogens; and the mechanisms of communication used during recognition between symbiotic rhizobia and their host legumes. Participants in the Symposium contributed a series of papers that represent the leading edge of research in this important area of plant and microbial science. These articles are brought together to form this book, which will be essential reading for research workers, advanced students and others interested in keeping abreast of this rapidly developing area.

The Fifth International Symposium on Nitrogen Fixation with Non-legumes was held in Florence (Italy) on 10-14 September, 1990. Earlier Symposia of this series were held in Piracicaba (Brazil), Banf Alberta (Canada), Helsinki (Finland) and Rio De Janeiro (Brazil). The Symposium's main objectives were to bring together scientists working in many different fields of nitrogen fixation, to stimulate discussion on this important process and to have an appraisal of the most recent studies concerning nitrogen fixation with non-legumes. The Symposium was attended by 230 scientists from 32 different countries. This volume collects the contributions of 65 lectures and 87 posters, which are an up-to-date account of the state of knowledge on biological nitrogen fixation with non-legumes. The book provides a valuable reference source not only for specialists in nitrogen fixation, but also for researchers working on related aspects of agronomy, biochemistry, genetics, microbiology, molecular biology and plant physiology. It is with great pleasure that we aknowledge the contributions of the authors in assuring the prompt pubblication of this volume. We would also like to express our thanks to Kluwer Academic Publishers B.V. for the publication of these Proceedings. M. Polsinelli R. Materassi M. Vincenzini ORGANIZING COMMITTEE President M. Polsinelli M. Vincenzini Secretary F. Favilli Treasurer E. Galli E. Gallori L. Giovannetti R. Materassi M.P. Nuti M.R. Tredici SCIENTIFIC COMMITTEE M. Bazzicalupo Florence, Italy H. Bothe Cologne, West Germany R.H. Burris Madison, U.S.A.

This book presents a detailed analysis of up-to-date literature on in vitro morphogenesis at cell, tissue, organ, and whole plant levels. Its driving force is the substantial advances made in the field of morphogenesis in tissue cultures during the last 25 years.

This publication comprises the proceedings of the first International Conference devoted to the structural roots of trees and woody plants. 'The Supporting Roots - Structure and Function, ' 20-24 July 1998, Bordeaux, France. The meeting was held under the auspices ofIUFRO WPS 2. 01. 13 'Root Physiology and Symbiosis, ' and its aim was to bring together scientific researchers, foresters and arboriculturalists, to discuss current problems in structural root research and disseminate knowledge to an audience from a wide disciplinary background. For the first time in an international conference, emphasis was placed on presenting recent reseach in the field of tree anchorage mechanics and root biomechanics. The way in which tree stability can be affected by root system symmetry and architecture was addressed, as well as how movement during wind sway can influence the development and shape of woody roots. The role of different nursery and planting techniques was discussed, in relation to effects on root system form and development. Root response to different environmental stresses, including water, temperature, nutrient and mechanical stress was addressed in detail. The structure and function of woody roots was also considered at different levels, from coarse to fine roots, with several papers discussing the interaction between roots and the rhizosphere. One of the conference highlights was the presentation of new methods in root research, by a series of workshops held at LRBB-INRA, Pierroton, on the northern border of the Gascony forest.

Saline land is a resource capable of significant production. Recent advances in research in breeding for salt tolerance in wheat, biotechnology in rice, and selection and rehabilitation of salt-tolerant plants are of economic importance in arid/saline conditions.

This book gives some practical approaches for saline agriculture and afforestation, and describes examples of cultivating salt-tolerant/halophytic plants for commercial interest on salt-affected land or with highly salinized water in Australia, China, Central Asia, Egypt, Pakistan, and Russia. It also explores the possibilities of arid/saline agriculture and afforestation in UAE.

It is now about 100 years since the chloroplast has been recognized as the site of photosynthesis in plant cells. The last 20 years have seen a striking increase in interest in the structure and function of the chloroplast. Hastened on by powerful new tools such as the electron microscope and the newer methods of isolation and analysis of chloroplasts, there is presently considerable experimental work on the properties of this organelle. In such a rapidly moving field and one which is reviewed systematically is various Annual Reviews, it is not possible to present a detailed critique of the prolific literature in a book of reasonable size. Rather the decision was made to sacrifice complete coverage of the field and to indicate general areas of investigation. In organization, problems here dealt with, are those concerned with the electron microscopy of chloroplast structure, development and conformation, genetic control of chloroplast development, characterization of some of the major components of the chloroplast and the biochemical properties of the chloroplast including the for mation of adenosine triphosphate and reduced pyridine nucleotide and the assim ilation of carbon dioxide into carbohydrate with subsequent conversion to second ary products. A historical outline on the general subject "Photosynthesis and the Chloroplast" has been included to place into proper perspective the rapid developments in the several areas covered in the book. I am particularly indebted to Dr. Roy E."

Research on the mechanisms of plant defense responses to stress and pathogen attack has attracted much attention in recent years. This increasing interest stems from the fact that the tools of molecular biology now enable us to study the molecular basis of old biological concepts such as host-pathogen recognition (and particularly the gene for-gene relationship), hypersensitive cell death and systemic acquired resistance. Our knowledge about avirulence and resistance genes, elicitors, signal transduction and genes involved in plant defense is rapidly expanding. Moreover we are just beginning to test in planta the potential of these results for biotechnological applications, aimed at improving plant resistance to diseases. The 2nd Conference of the European Foundation for Plant Pathology, hosted by the "Societe Fran~aise de Phytopathologie", was devoted to "Mechanisms of plant defense responses" and was held in Strasbourg, France. It brought together over 350 scientists from universities, research institutes and private sectors of 24 countries. Major advances in the areas under study have been reviewed in plenary lectures and are developed in the main articles of this book. Over 160 high-quality posters were presented and are summarized in short articles. Data from outstanding posters, which were discussed after a short oral presentation, are found in extended articles. As a whole the book presents a collection of papers arranged in six sections and reflecting the present day state-of-the-art of research in the field of plant defense reactions.

Considerable advances have been made in our understanding of the eukaryotic cell cycle at the molecular level over the past two decades or so, particularly in yeast and in animal systems. However, only in the past three or four years has progress been made in plants at the molecular level. The present volume brings together molecular biologists, cell biologists and physiologists to discuss this recent progress and how it relates to our understanding of the regulation of plant growth and development. The opening paper summarises the progress which has been made with fission yeast. Subsequent papers explore what is known about cell cycle control at the molecular level in plants, and about cell cycle regulation in specific physiological systems, ending with summary papers on cell division in roots and shoots. The book comprises up-to-date findings on a fundamental aspect of plant growth and development, and as such will be of particular interest to advanced undergraduates, postgraduates and research scientists in the fields of molecular biology, cell biology and physiology.

Significant developments in recent years have led to a deeper understanding of the role and function of carotenoids in photosynthesis. For the first time the biological, biochemical, and chemical aspects of the role of these pigments in photosynthesis are brought together in one comprehensive reference volume. Chapters focus on the photochemistry of carotenoids in light harvesting and photoprotection, the nature and distribution of carotenoids in photosynthetic organisms, their biosynthesis, the herbicidal inhibition of carotenogenesis and the xanthophyll cycle'. Throughout details are given of the various methodologies used. A detailed appendix provides physical data for the major compounds. Carotenoids in Photosynthesis is an invaluable reference source for all plant scientists.

JACQUES S. BECKMANN & THOMAS C. OSBORN Extraordinary progress has been made in the analyses of the genetic structures of higher eukaryotic genomes. Only ten years elapsed between the initial proposals to use molecular DNA markers for the generation of a complete linkage map of the human genome [5, 17] and the first description of a 10 centimorgan map of one of its chromosomes [22], soon to be followed by others. The availability of molecular DNA markers, henceforth called genomic markers [for a review of their properties see 1, 2, 20], represents a milestone in genetics by providing the capacity for complete genetic coverage of all genomes. It is important to remember that the nature of the DNA polymorphism or of the specific method used to uncover it can be quite different for different marker loci. The genetic variation detected can be a result of a simple point mutation, a DNA insertion/deletion event, or a change in repeat copy number at some hypervariable DNA [11] or micro satellite [21] motif. Currently, the methods of detection can involve use of restriction endonucleases, nucleic acid hybridization, or DNA sequence amplification. Each of these sources of var iation and methods of detection can have utility for different applications. Furthermore, new approaches for the detection of DNA polymorphism are constantly emerging. The primary concern here is that the monitored poly morphism defines a genetic marker 'useful' for the desired application.

Over the past decade, advances in molecular biology have provided the impetus for a resurgence of interest in plant metabolism. At a general level, the potential for modifying the quantity or quality of harvestable crop products through genetic manipulation has provided an agronomic rationale for seeking a greater understanding of primary plant metabolism and its regulation. Moreover, the now facile techniques for transformation of many plant species and the consequential capacity to manipulate the amounts of specific individual enzymes within specific cell types provides an exciting direct approach for studying metabolic problems. Such transgenic plants are also becoming invaluable tools in studies at the interface between metabolism and other sub-disciplines such as physiology and ecology. The interest generated in plant metabolism by these developments has also encouraged the re-introduction of more conventional biochemical techniques for metabolic analysis. Finally, in common with other areas of cell biology, the wealth of information that can be obtained at the nucleic acid level has provided the stimulus for identification and characterisation of metabolic processes in far greater detail than previously envisaged. The result of these advances it that researchers now have the confidence to address problems in plant metabolism at levels not previously attempted. This book presents the proceedings of an international conference held on 9-11 January 1997 at St Hugh's College, Oxford under the auspices of the Phytochemical Society of Europe.