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.

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.

The International Society of Root Research sponsored the Symposium "Root Demographics and Their Efficiencies in Sustainable Agriculture, GrassLands and Forest Ecosystems," July 14-18, 1996, at the Madren Conference Center, Clemson University, Clemson, South Carolina, USA. The conference was a continuation of a series of international symposiums on root research held every three to four years. Symposiums have also been held twice in Vienna, Austria, and once in Uppsala, Sweden, and Almaty, Kazahkstan prior to the meeting at Clemson University. The sponsoring society has made a particular effort in these symposia to include root scientists from the former Soviet Union because of the importance of exchanging information on a worldwide basis. This symposium continued and promoted that effort by providing travel grants to several scientists from that region; however, funds for that purpose were limited. Therefore, in compiling these proceedings, a number of papers from scientists from the former Soviet Union and former Warsaw Pack countries have been included even though the scientists were not actually present for the SymPOSIum.

From its inception, the U.S. Department of the Interior has been charged with a conflicting mission. One set of statutes demands that the department must develop America's lands, that it get our trees, water, oil, and minerals out into the marketplace. Yet an opposing set of laws orders us to conserve these same resources, to preserve them for the long term and to consider the noncommodity values of our public landscape. That dichotomy, between rapid exploitation and long-term protection, demands what I see as the most significant policy departure of my tenure in office: the use of science-interdisciplinary science-as the primary basis for land management decisions. For more than a century, that has not been the case. Instead, we have managed this dichotomy by compartmentalizing the American landscape. Congress and my predecessors handled resource conflicts by drawing enclosures: "We'll create a national park here," they said, "and we'll put a wildlife refuge over there." Simple enough, as far as protection goes. And outside those protected areas, the message was equally simplistic: "Y'all come and get it. Have at it." The nature and the pace of the resource extraction was not at issue; if you could find it, it was yours.

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.

All biomass is derived from photosynthesis. This provides us with food fuel, as well as fibre. This process involves conversion of solar energy, via photochemical reactions, into chemical energy. In plants and cyanobacteria, carbon dioxide and water are converted into carbohydrates and oxygen. It is the best studied research area of plant biology. We expect that this area will assume much greater importance in the future in view of the depleting resources ofthe Earth's fuel supply. Furthermore, we believe that the next large increase in plant productivity will come from applications of the newer findings about photosynthetic process, especially through manipulation by genetic engineering. The current book covers an integrated range of subjects within the general field of photosynthesis. It is authored by international scientists from several countries (Australia, Canada, France, India, Israel, Japan, Netherlands, Russia, Spain, UK and USA). It begins with a discussion of the genetic potential and the expression of the chloroplast genome that is responsible for several key proteins involved in the electron transport processes leading to O evolution, proton release and the production of 2 NADPH and A TP, needed for CO fixation. The section on photosystems discusses 2 how photosystem I functions to produce NADPH and how photosystem II oxidizes water and releases protons through an "oxygen clock" and how intermediates between the two photosystems are produced involving a "two electron gate".

In this study, an overview is presented of agricultural policies on manure and minerals, relating to the Nitrate Directive to remedy excessive surface- and groundwater contamination from intensive agricultural practices. Six countries belonging to the European Union were studied: the Netherlands, Belgium, Denmark, France, Germany and the United Kingdom. The policies and their legal incorporation were related to agricultural and environmental conditions in each country. In addition, an inventory was made of agricultural mineral poli cies in the United States and Canada. Conditions for livestock farming in North America differ considerably from those in Europe, but their solutions shed a different light on European policies. Research has shown that there are still very considerable mineral surpluses in many countries and regions. In both the Netherlands and in the Flemish part of Belgium, existing problems due to very high levels of manure production are structural rather than local and cannot easily be solved by transport of manure to other regions. To a lesser extent. Germany, Denmark and relatively small parts of France (Brittany) and the United Kingdom, still exceed the norms for an equilibrium fertilization. In Denmark, existing problems can probably be solved within the existing legislative framework. The Netherlands, Flanders. several German Lander (Nordrhein-Westfalen and Schleswig-Holstein) and Brittany.

In the Netherlands the Institute for Soil Fertility Research plays a major role in soil biological, soil physical and plant nutritional research on the availability of nitrogen to crops. Main subjects of research are nitrogen turnover in the crop-soil ecosystem through biological transformations, nitrogen transport through the soil and nitrogen losses by leaching, denitrification and volatilization, and nitrogen use efficiency of various crops and cropping systems. The current knowledge in the different fields of research is integrated in simulation models. Simulation models not only make it possible to summarize and structure knowledge, but also, after verification, to extra- late the knowledge to situations different from the situations that have actually been studied. Such research is also carried out in other European and non-European countries. To compare the various simulation models currently in use, a workshop was organized by the Institute for Soil Fertility Research on 5-6 June 1990 on the occasion of its centennial. The title of the workshop was 'Nitrogen turnover in the soil-crop:: cosystem: modelling of biological transformations, transport of nitrogen and nitrogen use efficiency'. The 40 Jarticipants, who came from Canada and various European countries, were requested to run their model with data Jrovided by the Institute prior to the workshop. Data from 18 cases were made available to the participants: three ocations, three treatments, and two seasons.

Many plants produce enzymes collectively known as ribosome-inactivating proteins (RIPs). RIPs catalyze the removal of an adenine residue from a conserved loop in the large ribosomal RNA. The adenine residue removed by this depurination is crucial for the binding of elongation factors. Ribosomes modified in this way are no longer able to carry out protein synthesis. Most RIPs exist as single polypeptides (Type 1 RIPs) which are largely non-toxic to mammalian cells because they are unable to enter them and thus cannot reach their ribosomal substrate. In some instances, however, the RIP forms part of a heterodimer where its partner polypeptide is a lectin (Type 2 RIPs). These heterodimeric RIPs are able to bind to and enter mammalian cells. Their ability to reach and modify ribosomes in target cells means these proteins are some of the most potently cytotoxic poisons found in nature, and are widely assumed to play a protective role as part of the host plant's defenses. RIPs are able to further damage target cells by inducing apoptosis. In addition, certain plants produce lectins lacking an RIP component but which are also cytotoxic. This book focuses on the structure/function and some potential applications of these toxic plant proteins.

Since 1994, the Phytochemical Society of North America has devoted its annual symposia to topics with biological perspectives. Our last four volumes have dealt with medicinal plants (1994), plant/insect interactions (1995), food phytochemicals (1996), and plant/microbe interactions (1997), respectively. The Symposium held in Pullman, Washington, July 26-31, 1998 brought many aspects of these previous symposia once again to the forefront. This time, however, there was greater emphasis on the potential applications of phytochemistry to the diverse topics of human health and nutrition and plant defense. As we learned about innovative uses of molecular biology as it is being applied to these topics, we were reminded once again of the biochemical th foundation on which these advances rest. On the occasion of the 75 birthday of G.H. Neal Towers, which we were privileged to celebrate, a perspective of where we began and how far we have advanced was made patently real for those in attendance. The papers assembled in this volume were presented during the Sympo- sium. Roughly grouped under three broad topics, they include: I. Drug Discov- ery and Pathway Engineering toward New MedicinallNutriceutical Targets (papers by Cragg, Croteau, Thompson, Costa, McLaughlin, Dixon, and Matern), 2. Roles for Polyphenols-Biosynthesis and Applications (Gross, Hillis, Haslam, and Ferreira), 3. New Chemical Prospects and Plant Defense (Asakawa, Selmar, Houghton, and Mizutani).

The Monograph deals with the conception, planning, implementation, results and conclusions of the International Witches' Broom Project (IWBP), which was set up in 1985 with the aim of producing an economic management system for witches' broom disease of cocoa. The contributions of the various sponsors, and the roles played by the participating organizations and scientists are described in the introductory chapter. Chapter 2 provides a review of what was, and what was not known from published literature about the cocoa witches' broom pathosystem in 1989. The scope of the project and the approaches used are covered in Chapter 3, while Chapters 4 to 13 report on the field studies themselves in detail. The recent appearance of witches' broom in the important cocoa area of Bahia in Brazil is described in Chapter 14, before disease management recommendations are summarised and future prospects considered in the closing chapters. The many man-years of field research in the IWBP in a total of six countries generated much useful information which was analyzed both in the individual countries and collectively. Even with a document of this size, certain information and analyses with less direct relevance to disease management had to be omitted. It is expected that more detailed treatments of certain aspects will emerge in scientific papers, and further analyses will be undertaken."

The dynamic role of plant hormones in regulation of plant growth and development revealed by its control of rates of metabolic processes and various related enzymetic reactions at molecular and submolecular levels is now weil established. During the course of last 35 years endless development in agricultural biotechnology has provided immense literature to understand hormone-regulated aspects of plant growth and development ; but plant physiologists all over the world are still devoting themselves and will continue for an indifinite period to disclose the mystries of this regulation. Volume I of this series has already been published and has been accepted weil. This encouraged me to edit aseries of volumes (I do not know the number) on this subject. In the following pages various aspects of hormone-controlled physiological processes Iike, Hormonal Control of pro tein synthesis in plants, Auxin-induced elongation, Hormonal regulation of abnormal growth in plants, Hormonal regulation of development in mosses, Some phenolics as plant growth and morphogenesis regulators, Plant growth regulating properties of sterol inhibiting fungicides, Hormonal regulation of sex expression in plants, Water relation and plant growth regulators, Hormonal regulation of root development under water stress, Gravity perception and responses meehanism in graviresponding cereal grass shoots, Hormonal regulation of leaf Growth senescence in relation to stomatal movement, and Chloroindole auxins of pea and related species, have been included.

The refinement of molecular techniques and the development of new probes of the phylogeny of diazotrophs has revealed an extreme biodiversity among the nitrogen fixers, which helps explain the role that nitrogen fixation plays in maintaining life on Earth. The most efficient ecosystems are those where the bacteria are associated with a plant in differentiated organs to benefit crop productivity. Most short-term benefit from fundamental research on nitrogen fixation is likely to result in the improvement of existing nitrogen-fixing symbiotic or associative systems. Longer-term efforts are aimed at extending the nitrogen-fixing capacity to other organisms, including transfer of the genetic information for efficient nitrogen fixation into the plant genome and using current knowledge of microbe-plant interactions to extend symbiosis to cereals and, in particular, to rice. Related challenges in sustainable agriculture and forestry include the creation of new nitrogen-fixing associations. All of these approaches were discussed at the 11th International Congress on Nitrogen Fixation, Paris, France, July 20-25, 1997 and covered in the present proceedings volume.

Plants live in a constantly changing environment from which they cannot physically escape. Plants therefore need signalling and response mechanisms to adapt to new local conditions. The ef?cacy of such mechanisms underlies the plant performance during stress and therefore also impacts greatly on agricultural productivity. M- ulation of ion channel activity not only provides a means for rapid signal generation 2+ but also allows adjustment of cellular physiology. For example, Ca permeable ion 2+ channels can transduce environmental stimuli into Ca -encoded messages which can modify the gene expression. Furthermore, ion channel activity is essential to control cellular ion homeostasis that impacts on plant responses to drought, salinity, pathogens, nutrient de?ciency, heavy metals, xenobiotics and other stresses. This volume focuses on the crucial roles of different types of ion channel in plant stress responses. Functions of ion channels are discussed in the context of mechanisms to relay external and endogenous signals during stress and as mechanisms to regulate cellular ion homeostasis and enzymatic activities in the context of biotic and abiotic stress. The chapters presented cover cation and anion channels located in various cellular compartments and tissues.

The double helix architecture of DNA was elucidated in 1953. Twenty years later, in 1973, the discovery of restriction enzymes helped to create recombi nant DNA molecules in vitro. The implications of these powerful and novel methods of molecular biology, and their potential in the genetic manipulation and improvement of microbes, plants and animals, became increasingly evi dent, and led to the birth of modern biotechnology. The first transgenic plants in which a bacterial gene had been stably integrated were produced in 1983, and by 1993 transgenic plants had been produced in all major crop species, including the cereals and the legumes. These remarkable achieve ments have resulted in the production of crops that are resistant to potent but environmentally safe herbicides, or to viral pathogens and insect pests. In other instances genes have been introduced that delay fruit ripening, or increase starch content, or cause male sterility. Most of these manipulations are based on the introduction of a single gene - generally of bacterial origi- that regulates an important monogenic trait, into the crop of choice. Many of the engineered crops are now under field trials and are expected to be commercially produced within the next few years. The early successes in plant biotechnology led to the realization that further molecular improvement of plants will require a thorough understanding of the molecular basis of plant development, and the identification and charac terization of genes that regulate agronomically important multi genic traits.

This is the third annual compendium of a Technical Session of the Physiology Working Group of the Society of American Foresters held at the National Convention. Specialists in a dedicated area of tree physiology were invited to prepare chapter contributions synthesizing the status of knowledge in their area of expertise. Plant growth regulators (PGRs) was selected as the topic for in-depth examination at the 1986 Technical Session because a knowledge of how these "secondary messengers" regulate tree morphogenesis is vital to applications of biocontrol and biotechnology. Plant growth regulators have been the subject of numerous reviews in recent years. However, few have dealt specifically with woody perennials, and they are generally confined to single processes and/or organs. This volume attempts to provide a more comprehensive treatise of PGRs as they influence various ontogenetic events in forest trees. Reproductive physiology, both sexual and asexual, is emphasized because of its relevance to current efforts directed at increasing efficiency in the breeding and production of genetically improved trees for reforestation. The chapters on vegetative growth will be of interest to silviculturists and urban foresters as they consider cultural treatments in the management of forests and individual trees for specific products and purposes. This book should serve as a valuable text and source of reference for students, researchers and other professionals interested in gaining a better understanding of PGRs. The reader, however, who expects definitive answers to how PGRs function or can be used to control specific processes is likely to be disappointed.

It is appro pi ate to the contents of this book to recall a few highlights in the history of plant cytology from its inception over three centuries ago. Robert Hooke in 1663 presented his observations of what he called " cells" in cork and other plant parts and beautifully illustrated and described these in his classic " Micrographia" published two years later. More detailed exploration of the cell and its contents awaited almost two centuries for Robert Brown's discovery of the nucleus in 1831. Discoveries of other cell organelles followed, particularly in the latter part of the 19th and early part of this century. As is frequently noted each of these achievements was preceeded by advances in the resolution of the microscope. Now history repeats and recent developments in electron microscopy have given the biologist the opportunity to study cell morphology in far greater detail than at any time previously. Indeed, the resolution of the electron microscope is several hundredfold better than that available in the finest light microscopes. These advances in instrumentation plus improvements in the techniques of specimen preparation have made possible the ex amination of plant cells of almost any type. It is the resulting wealth of new information now accessible to the botanical cytologist that has prompted this publication. In this book we have brought together electron micrographs represent ing a number of cell types from higher plants.

What are plant growth regulators? In the title, and throughout the text, we have adopted this expression to describe a population of endogenous molecules and synthetic compounds of similar structure that are be lieved to play important roles in the regulation of plant differentiation and development. For many years, plant scientists have endeavoured to understand the nature and action of plant growth regulators and, as a result, an awesome quantity of written material now exists describing these chemicals and their effects. In this book we have aimed to distil this wealth of information into a more digestible form, and in particular we have focused our attention on a critical appraisal of the literature. The past few years have witnessed a change of emphasis in plant growth regulator research, which has been fuelled by powerful new techniques in molecular and cell biology. Today we can do more than just apply a plant growth regulator and quantify its effects; we have reached an exciting crossroads where plant scientists, molecular bio logists and chemists can pool their expertise and apply it to the out standing problems in this area. The combination of these three disciplines within the book is clear evidence of this. In keeping with a volume of this size, we have assumed that the reader has a sound knowledge of plant physiology and biochemistry. However, wherever possible, we have highlighted useful reviews which provide background information, along with recent publications that have contributed significantly to the literature."

Origins of Plastids looks at symbiosis and symbiogenesis as a mechanism of evolution. This theory of endosymbiotic evolution postulates that photosynthetic prokaryotes living as endosymbionts within eukaryotic cells gradually evolved into the organelle structures called chloroplasts. The theory is controversial but has been strongly advocated by Lynn Margulis. Based on a colloquium held at the Bodega Bay Marine Laboratory of the University of California at Davis, Origins of Plastids reviews recent data on this most basic problem in plant evolution. In it, leading researchers in the field apply the theory of endosymbiotic evolution to plastid origins, producing an important new reference work for both professionals and graduates interested in the origins of life, the origins of the eukaryotic cell and its organelles, and the evolution of the higher plants in general. Origins of Plastids represents the state-of-the-art in its field. It should find a place on the bookshelves of people interested in microbiology, plant science, phycology, cell biology, and evolution.

The ecology of world vegetation is described in numer all of the drafting and photographic work. They have ous books and journals, but these are usually very spe spent many hours on this project and their care and skill cialized in their scope and treatment. This book provides is reflected in the consistently high quality of the illus a synthesis of this literature. A brief introductory chap trations throughout the book. Many friends and col ter outlines general ecological concepts and subsequent leagues have provided photographs. It has not been chapters examine the form and function of the major possible to include all of them, but the 'global' perspect biomes of the world. A similar organization has been ive of the book has been greatly enhanced in this way. used for each biome type. These chapters begin with a I wish to thank them all for the time and trouble they description of environmental conditions and a brief have taken to supply this material. I must also thank account of floristic diversity in a regional context. The Mary Dykes and the staff of the interlibrary loans de remaining pages describe characteristic adaptations and partment of the Library, University of Saskatchewan, ecosystem processes. for their unfailing ability to get even the most obscure Although there is a rapidly growing literature on eco references."

It is very clear nowadays that plants offer several opportunities for basic studies, e.g. on development and embryogenesis, and that the fundamental principles laid open contribute to the development of new tools for plant breeding. Within the scope of the present publication, the editors have had to make a difficult choice from the many important subjects that have contributed to the remarkable progress of our molecular biological understanding of complex biological problems. This has resulted in review papers showing the present state of the art in genetic engineering, gene expression and its manipulation, microbe and insect interactions with plants, transposable elements and gene tagging, plant and organ development, the function and structure of the genome chloroplasts, and lipid biosynthesis. All papers have been written in such a way that they are also useful for non-experts interested in a particular field, as well as for students following courses in plant molecular biology. Besides presenting the state of the art, each paper gives some historical background to the developments in the field as well as perspectives for further basic research and applications. Because of the latter, scientists and students engaged in plant breeding will also profit from this publication.

Ethylene is a simple gaseous plant hormone produced by higher plants, bacteria and fungi. Thanks to new tools that have become available in biochemistry and molecular genetics, parts of the ethylene biosynthesis, perception and signal transduction reactions have been elucidated. This knowledge has been applied to enhance the quality of a number of agronomically important crops. In Biology and Biotechnology of the Plant Hormone Ethylene, leading figures in the field provide surveys of the current state of ethylene biosynthesis and action, perception and signal transduction pathways, senescence, biotechnological control, and the involvement of ethylene in pathogenesis and stress. Audience: Indispensable to all academic, industrial and agricultural researchers as well as undergraduates and graduates in plant biology, biochemistry, genetics, molecular biology and food science.

It is paradoxical that, despite the key role of plants in the book's preparation by reviewing manuscripts or the environment and our dependence on plant life for providing literature and case studies for inclusion. our very existence, the conservation movement has The preparation of the text, which went through var not given plants attention that is commensurate with ious drafts, involved Dr. Given in a great deal of re their importance. In an attempt to redress the balance search and travel for fact finding and consultation. of effort between plant and animal conservation, The completed draft was edited by Martin Walters, IUCN and WWF established in 1984 a joint Plant who also prepared it for publication. Professor Ver Conservation Programme, the aim of which was to non Heywood (IUCN) undertook a scientific edit of "assert the fundamental importance of plants in all the final draft. conservation activities: ' Both IUCN and WWF would like to express their gratitude to Dr. Given for the enormous effort and One of the main themes of the joint Plant Conser painstaking labor that he has invested in the prepara vation Programme was "building the capacity to con serve. " This included a project, "Plant Conservation: tion of this book over a period of six years. The result Principles and Practice," aimed at providing practic is the first detailed overview ever to be published of ing conservationists with a handbook that explained this vitally important subject."

Frontiers of Industrial Mycology describes the present efforts underway to create a broad range of large-scale applications using filamentous fungi. Important and environmentally sound applications currently being developed include the use of fungi for novel *B-lactams in antibiotic production, biobleaching and the bioconversion of wood pulp, agricultural biotechnology for creating biological insecticides and herbicides, food fermentations, and the commercial raising of shiitake mushrooms, a growing and largely untapped market in North America. The topics discussed in this volume are on the cutting edge of industrial mycology. This book will thus benefit a wide range of professionals and academics in biotechnology, mycology, microbiology, plant science, entomology, and biochemistry.

Plant Molecular Biology Manual (Second Edition) is an entirely new manual containing both fundamental and recently described techniques in the area of plant molecular biology. Designed for use in the research laboratory, the Plant Molecular Biology Manual presents detailed techniques in the areas of plant transformation, recombinant DNA and other nucleic acid manipulations, nuclear run-on and in vitro transcription systems, in situ hybridization and immunodetection systems, protein-nucleic acid interaction analyses, subcellular targeting of proteins in the plant cell, and gene tagging using T-DNA and transposons. This second edition contains more than 40 newly written chapters, including descriptions of subjects such as virus-mediated gene transfer, specialized Agrobacterium strains and T-DNA vectors, nuclear run-on and in vitro transcription systems, non-radioactive detection systems, characterization of transcription factors, nuclear protein targeting, and T-DNA and transposon mutagenesis, not previously described in the first edition.