Higher eukaryotes are characterized by the allocation of distinct functions to numerous types of differentiated cells. Whereas in animals the well-defined, protected cells of the germ line separate early, germ cells in plants differentiate from somatic cells only after many cycles of mitotic division. Therefore somatic mutations in plants can be transmitted via the germ cells to the progeny. There is thus a clear need for somatic tissues to maintain their genetic integrity in the face of environmental challenges, and two types of interactions have been shown to play important roles in the conservation as well as flexibility of plant genomes: homologous recombination of repeated sequences and silencing of multiplied genes. Sensitive methods have been developed that allow greater insights into the dynamics of the genome. This book summarizes current knowledge and working hypotheses about the frequencies and mechanisms of mitochondrial, plastid, nuclear and viral recombination and the inactivation of repeated genes in plants. Despite rapid developments in the field, it is often not possible to provide final answers. Thus, it is an additional task of this book to define the open questions and future challenges. The book is addressed to scientists working on plant biology and recombination, to newcomers in the field and to advanced biology students.

Many agricultural crops worldwide, especially in semi-arid climates, suffer from iron deficiencies. Among plants sensitive to iron deficiency are apples, avocado, bananas, barley, beans, citrus, cotton, grapes, peanuts, pecans, potatoes, sorghum, soybeans, and numerous ornamental plants. Deficiencies are usually recognized by chlorotic, in new leaves and are typically found among sensitive crops grown in calcareous or yellowed, interveinal areas soils which cover over 30% of the earth's land surface. Iron deficiency may lead, in extreme cases, to complete crop failure. In intensive agriculture on calcareous soils, iron often becomes a major limiting nutrient for optimal crop production, thus, correction of iron deficiency is required. Various chemicals and practices are available. They are, however, costly and do not always result in a complete remedy of the deficiency. Crucial questions relative to the cost-benefit equation such as the recovery rate of plants and the long-term fertilizing effect have not yet been resolved. The complexity of iron nutrition problems requires an understanding of the chemistry of iron oxides in soils, of the chemistry of both natural and synthetic chelates, of rhizosphere microbiology and biochemistry, and of the physiological involvement of the plant in iron uptake and transport.

Plant Production on the Threshold of a New Century describes and compares problems and frontier developments in the different sectors of plant production, integrating developments in basic plant sciences, crop science and socioeconomic science, leading to sustainable plant production. Hence the book formulates goals and constraints in policy, economy, production, environment and land use; indicates how these goals and constraints may be translated into farming styles and cropping systems; and describes how the fundamental plant sciences can contribute to the implementation of such farming styles and cropping systems.

Proceedings of the International Workshop on Gelidium held in Santander, Spain, September 3-8, 1991

The study of plant development using molecular and genetic techniques is rapidly becoming one of the most active areas of research on flowering plants. Developmental Biology of Flowering Plants relates classical developmental work with the outstanding problems of the future in the study of plant development. An important feature of this book is the integration of results from molecular and genetic studies on various aspects of plant development in a cellular and physiological context.

In recent decades, repeated use of herbicides in the same field has imposed selection for resistance in species that were formerly susceptible. On the other hand, considerable research in the private and public sectors has been directed towards introducing herbicide tolerance into susceptible crop species. The evolution of herbicide resistance, understanding its mechanisms, characterisation of resistant weed biotypes, development of herbicide-tolerant crops and management of resistant weeds are described throughout the 36 chapters of this book. It has been written by leading researchers based on the contributions made at the International Symposium on Weed and Crop Resistance to Herbicides held at Cordoba, Spain. This book will be a good reference source for research scientists and advanced students.

With an ever-increasing demand for more food supply, agricultural scientists will have to search for new ways and technologies to promote food production. In recent decades, plant growth regulators (PGRs) have made great strides in promoting plant growth and development. PGRs are organic compounds which have the ability to dramatically affect physiological plant processes when present in extremely low concentrations (in the range of micro-to picograms). Although all higher plants have the ability to synthesize PGRs endogenously, they do respond to the exogenous sources most likely due to not having the capacity to synthesize sufficient endogenous phytohormones for optimal growth and development under given climatic and environmental conditions. In recent years, PGRs have established their position as a new generation of agrochemicals after pesticides, insecticides and herbicides. Interest in the commercial use of PGRs for improving plant growth and crop yields is also increasing because of their non-polluting nature. The use of PGRs in the post-harvest technology is well established and many new breakthroughs have recently been revealed.

In vitro Embryogenesis in Plants is the first book devoted exclusively to this topic. As the ultimate demonstration of totipotency in plants, somatic and haploid embryogenesis is of vital importance to all those working on or interested in basic and applied aspects of plantlet information and regeneration. The text includes comprehensive reviews written by experts, on all facts of in vitro and in vivo embryogenesis. Some chapters deal with the morphogenic, structural and developmental, physiological and biochemical, and molecular biological aspects of the subject. Chapters are also devoted to haploid embryogenesis, asexual embryogenesis in nature, zygotic embryogenesis, and zygotic embryo culture. Detailed tables summarizing successful somatic embryogenesis in all vascular plants are also included. This book, therefore, brings together previously scattered information to provide an indispensable reference book for both active researchers, graduate students and anyone interested in this aspect of tissue culture technology and plant development.

Commercial development of cultured-derived food ingredients has attracted interna tional interest. As consumers have become more health conscious in recent years, the de mand for natural food ingredients and disease-preventative phytochemicals has increased tremendously. Plant Cell and Tissue Culture provides an alternative method for controlled production of these products. A wide range of food ingredients has been shown to be pro duced in culture. Much progress has been made in advancing this technology to the point that large-scale production has become possible. This book is developed from the Symposium "Plant Cell and Tissue Culture for Food Ingredient Production" which was held on April 13-17, 1997 at the American Chemical So ciety National Meeting in San Francisco, CA. In this book, international experts in acade mia, government, and industry discuss current advances in the field of plant cell and tissue culture with special emphasis on its application for food ingredient production. Topics re lated to various aspects of plant cell and tissue culture technology are discussed, including overviews of recent advances in plant metabolic pathway studies, process development for improving yields, and bioreactor design and operation for large-scale production. Economic considerations and issues related to the commercial development of culture-derived food in gredients are discussed. Also included are the safety assessment schemes and regulatory frameworks set up by regulatory agencies around the world.

The economic significance of boron (B) in agriculture, horticulture, and forestry has been beyond dispute for several decades. Even in the last two decades, the areas where B deficiency limits plant production has grown with increased reports from China, south Asia and southeast Asia. The present volume is reflective of the growing awareness of the significance of low soil B with reports from Australia, Bangladesh, Brazil, north, central and southern China, India, Nepal, and the North West Frontier Province of Pakistan contained herein. Boron deficiency also continues to be a problem for crop yield and quality in areas where B deficiency has been known for some time, for example in Germany and the USA. The problem of low soil B is not limited to effects on field crop yield, with papers reporting on depressed wood yield and quality in timber trees (Lambert et al. ), and depressed fruit quality (Dong et al. ; Smith et al. : Zude et al. ) also appearing in the present volume. Globally, Shorrocks (1997)1 estimates that ?? tonnes of B fertiliser is applied annually in agriculture. The economic benefits from the use of B fertiliser have not been quantified but are clearly enormous. Paradoxically, the clear economic imperatives for using B fertiliser on low B soils are not matched by a similar clarity of understanding of the role and functions of B in plants.

Over forty years ago, concern was first focussed on cadmium contamination of soils, fertilisers and the food chain. Adverse effects on human health were first highlighted nearly 30 years ago in Japan with the outbreak of Itai-itai disease. Since then, substantial research data have accumulated for cadmium on chemistry in soils, additions to soils, uptake by plants, adverse effects on the soil biota and transfer through the food chain. However, this information has never been compiled into a single volume. This was the stimulus for the Kevin G. Tiller Memorial Symposium "Cadmium in Soils, Plants and the Food Chain", held at the University of California, Berkeley, in June 1997 as part of the Fourth International Conference on the Biogeochemistry of Trace Elements. This symposium brought together leading scientists in the field of cadmium behaviour in soils and plants, to review the scientific data in the literature and highlight gaps in our current knowledge of the subject. This series of review papers are presented here and deal with the chemistry of cadmium in soils, the potential for transfer through the food chain and management to minimise this problem. We hope this information provides a sound scientific basis to assist development of policies and regulations for controlling cadmium in the soil environment.

r ed Algae in Genome Age book most people reading this book have childhood memories about being enthralled at the beach with those rare and mysterious living forms we knew as seaweeds. We were fascinated at that time by their range of red hues and textures, and most of all, their exotic beauty. t o a scientist, red algae represent much more than apparent features. t heir complex forms have attracted morphologists for centuries; their intricate life cycles have brought more than one surprise to plant biologists familiar only with ferns and fowering plants; their unusual tastes have been appreciated for mill- nia, and their valuable chemical constituents have been exploited for nearly as long, most recently by biotech companies; their diversity in marine, freshwater, and t- restrial environments has offered centuries of engaging entertainment for botanists eager to arrange them in orderly classifcation systems; still, the red algae continue to teach us how many more challenges need to be overcome in order to understand their biodiversity, biological functions, and evolutionary histories.

Tea is a unique crop and, incidentally, a very interesting and attractive one. The tea bush, its cultivation and harvesting do not fit into any typical cropping pattern. Moreover, its processing and marketing are specific to tea. Thus the Tea Industry stands apart and constitutes a self contained entity. This is reflected in the title given to this book, Tea: Cultivation to consumption, and its treatment of the subject. The book is logically planned - starting with the plant itself and finishing with the traditional'cuppa'. Every aspect of tea production is covered, inevitably some in greater detail than others. However, it gives an authentic and comprehensive picture of the tea industry. The text deals in detail with cultural practices and research, where desirable, on a regional basis. The technology of tea cultivation and processing has been developed within the industry, aided by applied research which was largely financed by the tea companies themselves. This contributed to a technically competent industry but tended to bypass the more academic and fundamental investigations which might bring future rewards. The sponsorship of research has now widened and the range and depth of tea research has increased accordingly. The editors and authors of this book have played their part in these recent developments which are well reported in the book.

Science is essentially a descriptive and experimental device. It observes nature, constructs hypotheses, plans experiments and proposes theories. The theory is never contemplated as the 'final truth', but remains ever subject to modifications, changes and rejections. The science of allelopathy in a similar way has emerged, and exists on a similar footing; our endeavour should be to keep it fresh and innovative with addition of newer in formation and concepts with the rejection of older ideas and antiquated techniques. During the past few decades encouraging results have been obtained in various aspects of allelopathic researches. However, in addition to continuing efforts in all these directions, constant attempts are to be made to describe the mechanics of allelopathic activity in molecular terms and to discover ways and means to exploit it for the welfare of mankind. We feel that multidisciplinary efforts are the only tool to achieve this goal. It is the hope of the editors that this book will serve as a document which identifies an integrated approach, through which research both to understand and exploit allelopathy can be conducted. The present volume arose out of an attempt to bring together eminent scientists in allelopathy to describe their work, of a highly diverse nature, under one title."

However, the transition from primitive to 'advanced' cultivars has had the effect of narrowing the genetic base. This has happened in two distinct ways: (1) selection for relative uniformity, resulting in 'pure' lines, multi lines, single or double hybrids, etc.; and (2) selection for closely defined objectives. Both of these processes have resulted in a marked reduction in genetic variation. At the same time, there has been a tendency to restrict the gene pool from which parental material has been drawn. This is a result of the high level of productivity achieved when breeding within a restricted but well-adapted gene pool, and of breeding methods which have made it possible to introduce specifically desired improvements, such as disease resistance and quality characteristics, into breeding stocks with a minimum of disturbance to genotypic structure. Developments in agriculture, such as intensive mechanization, the widespread application of fertilizers and the use of herbicides, fungicides and pesticides, have created a situation whereby a few, selected high yielding cultivars may be grown over large parts of the earth, so further contributing to a decline in crop genetic diversity. This process is under way in all countries, both developed and developing, and unfortunately in cludes some of the richest primary and secondary gene centres of several important food crops."

Plant-Microbe Interactions, Volume 2 Volume 1 of this series has made its appearance and dealt forcefully with impor tant current topics in the field of plant-microbe interactions. We believe that the quality of those chapters was high and should serve as a focal point for the state of the art as well as an enduring reference. Volume 2 builds upon these accom plishments. Chapter 1 discusses the fascinating lipo-chitin signal molecules from Rhizo bium, aspects regarding their biosynthesis, and the basis for host specificity. These molecules are a cardinal example of how microorganisms influence plant development and stimulate speculation that they have identified a previously un known aspect of plant hormone activity. Chapter 2 continues the discussion of Rhizobium by considering the trafficking of carbon and nitrogen in nodules. Al though the ostensible advantage of nodules to plants is the fixation of atmos pheric nitrogen, the actual process involved in supplying reduced nitrogen to the plant host is complex."

Currently one of the hottest topics in biochemistry, the concept of molecular chaperones has challenged the paradigm of protein self-assembly. Key figures in many disciplines review all aspects of molecular chaperones in this volume, which arises from a Royal Society discussion meeting. Overview chapters discuss the significance of chaperones in biochemistry, molecular genetics and cell biology. Each chapter is well referenced providing access to the literature.

This volume contains selected papers presented at the First Balkan Botanical Congress. The articles refer to all groups of plants and to all scientific disciplines in plant sciences and cover several major themes of current interest to botanists: taxonomy, geobotany and evolution: flora, vegetation, geographical distribution, pollen morphology and deposition, biodiversity, conservation, phytosociology biochemistry, metabolism and bioenergetics: secondary metabolites, enzymes, membrane transport, virus infection ecology and ecophysiology: metal accumulation and tolerance, toxicity and pollution, bio-monitoring systems, dynamics of vegetation communities, leaf structure and ecological types, UV-B and ozone radiation, pesticides and herbicides, ecological evaluation, management and protection of ecosystems, adaptation, photosynthesis structure and its dynamics: organization and molecular characterization of biomembranes and different cell structures and organelles, ultrastructure, anatomy, biosynthesis and localization of different cell compounds genetics, plant breeding and biotechnology: gene transfer, genetic engineering, genetic sterility and diversity, biodiversity and conservation, in vitro regeneration, micropropagation, genotype-environment interaction growth, development and differentiation: differentiation of cell structures, reproductive biology, photoreceptors, crop simulation model, regulators and plant morphogenesis, plant growth patterns, somatic-embryogenesis and organogenesis.

The 1997 European Conference on Spectroscopy of Biological Molecules (ECSBM) is the seventh in a biennial series of conferences devoted to the applications of molecular spectroscopy to biological molecules and related systems. The interest of these conferences rests mainly on the relationship between the structure and physiological activity of biological molecules and related systems of which these molecular species form part. This volume ofECSBM contains articles prepared by the invited lecturers and those making poster presentations at the seventh ECSBM. The reader will find mainly applications of vibrational spectroscopy to protein structure and dynamics, biomembranes, molecular recognition, nucleic acids and other biomolecules and biological systems containing specific chromophors. Biomedical applications of vibrational spectroscopy are expanding rapidly. On the other hand, a significant number of the papers describe applications of other methods, such as NMR, circular dichroism, optical absorption and fluorescence, X-ray absorption and diffraction and other theoretical methods. One aim has been to achieve a well balanced, critically comparative review of recent progress in the field of biomolecular structure, bonding and dynamics based on applications of the above spectroscopic methods. A great part of the contributions included in this volume are devoted to biomedical and biotechnological applications and provide a broadly based account of recent applicationS in this field. The content of this book has been organized in sections corresponding mainly to the different types of biological molecules investigated. This book includes also another section related to theoretical methods where MO calculations of vibrational frequencies dominate clearly the topic.

Chemical reactions and interactions between molecules are commonly considered the basis of life, and thus the biochemical nature of cells and organisms is relatively well recognized. Research conducted in recent years, however, increasingly indicates that physical forces profoundly affect the functioning of life at all levels of its organization. To detect and to respond to such forces, plant cells and plants need to be structured mechanically. This volume focuses on mechanical aspects of plant life. It starts with a consideration of the mechanical integration of supracellular structures and mechanical properties of cellular building blocks to show how the structural integrity of plant cells is achieved and maintained during growth and development. The following chapters reveal how the functioning of integrated plant cells contributes to the mechanical integration of plants, and how the latter are able to detect physical stimuli and to reorganize their own cells in response to them. The mechanical aspects of plant responses to stresses are also presented. Finally, all these aspects are placed in an evolutionary context.

th We compiled this volume mostly from presentations at the 6 International Plant Cold Hardiness Seminar (PCHS) after consulting with Professor Tony H. H. Chen, Oregon State University, USA, Professor Pekka Heino, University of Helsinki, Finland, th and Dr. Gareth J. Warren, University of London, Surrey, UK. The 6 International PCHS was held at the Unitas Congress Center, Helsinki, Finland from July 1-5, 2001. There were 110 registered scientists at the serttinar representing 20 countries: Australia, Belgium, Canada, Chile, the Czech Republic, Denmark, Estonia, Finland, Gennany, Hungary, Iceland, Italy, Japan, Norway, Poland, Spain, Sweden, Taiwan, United Kingdom, and United States of America. The infonnation compiled represents the state of the art of research in phmt cold hardiness in tenns of gene regulation, gene expression, signal transduction, the physiology of cold hardiness and, ultimately, the genetic engineering for cold tolerant plants. The International PCHS was initiated in 1977 at the University of Minnesota, St. Paul, Minnesota. It has been traditionally held at 5-year intervals at various locations. th Because of the rapid advances of research in plant cold hardiness, attendees at the 6 meeting unanimously adopted a resolution to hold the seminar in 3-year intervals instead of 5 in the future. Consequently, the next seminar will be held in 2004 in Sapporo, Japan, and Professor Seizo Fujikawa from Hokkaido University will serve as the host.

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."

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.

For 31 years, the North American Symbiotic Nitrogen Fixation Conference (for merly Rhizobium Conference) has been a forum for scientists and graduate students to discuss their research advances, extending from basic aspects to agricultural appli cations, and dealing with topics ranging from bacterial genetics and metabolism to plant genetics and physiology. Nitrogen fixation, being a major life-supporting process on this planet, has attracted the interest of researchers for more than one century. Nitrogen fixation is responsible for the conversion of "inert" dinitrogen (N ) gas from the atmos z phere into usable ammonia, replacing the fixed nitrogen constantly being lost to the atmosphere by the denitrification process. Worldwide agricultural productivity is deter mined by the availability of fixed nitrogen in all its forms, which the continually increas ing human population depends upon for survival. An international momentum is developing in the use of biofertilizers to improve legume and non-legume crop yields and in the study of genomics in this area. New studies are being undertaken in several laboratories to study novel nitrogen-fixing systems, including non-legume crops. The North American Conferences on Symbiotic Nitrogen Fixation have periodically chronicled the advances in our knowledge of this area. For the first time, this conference was held in Mexico. Thus, all three North Amer ican countries have been hosts for this event. This year conference brought nearly 200 scientists from 18 different countries presenting lectures and over 80 posters.

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.