The inflorescence of the monoecious maize plant is unique among the Gramineae in the sharp separation of the male and female structures. The male tassel at the terminus of the plant most often sheds pollen before the visual appearance of the receptive silks of th the female ear at a lateral bud, normally at the 10 leaf [I]. Earlier studies examined the ontogeny of the growing tissues beginning with the embryo in the kernel through to the obvious protuberances of the growing point as the kernel germinates. The differentiated developing soon-to-become tassel and the lateral bulges that develop into the ears on the lateral buds become apparent very early in the germinating kernel [2, 3, 46]. A certain number of cells are destined for tassel and ear development [8]. As the plant develops, there is a phase transition [\3, 16] from the vegetative lateral buds to the reproductive lateral buds. This change in phase has been ascribed to genotypic control as evidenced in the differences among different genotypes in the initiation of the reproductive [I]. The genetic control of tassel and ear initiation has been gleaned from anatomical observations. Lejeune and Bernier [I2] found that maize plants terminate the initiation of additional axillary meristems at the time of tassel initiation. This would indicate that the top-most ear shoot is initiated on the same day as the initiation of tassel development and this event signals the end of the undifferentiated growing point.

This book includes papers from keynote lecture and oral presentations of Plant and Microbe Adaptations to Cold (PMAC) 2012, an international conference on winter hardiness of crop and pathogenic microbes. The PMAC has been started in 1997 in Japan as an interdisciplinary forum for scientists and extension people working in the field in plant pathology, plant physiology, microbiology, and crop breeding to increase our knowledge and improve our understanding of overwintering of crops, forages and grasses and solve the problems associated with losses due to freezing and heavy snow cover. Successive meetings have been held in Iceland (2000), Canada (2003), Italy (2006), and Norway (2009). PMAC2012 will be a special meeting with a focus on global climate change, food security and agriculture sustainability and the whole program will be arranged to reflect this theme. The topics covered by this proceedings includes, global warming in agricultural environment, plant adaptations to cold, microbial adaptations to cold, plant-microbe interaction under cold, and molecular breeding for winter hardiness. The researches range from molecular biology to ecology and breeding. Experts in the field will report cutting edge research and thoughtful strategies for sustainability.

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."

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.

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.

Photosynthesis--the capture of light energy by living organisms -is a simple enough concept, but its investigation draws on the resources of disciplines from all fields of science. The aim of this text is to provide a clear, stimulating and essentially affordable coverage for undergraduate students of biology. The activity of science is debate and practical experiment; its product is a body of propositions which at any given time reflects the judgment and prejudices of those taking part. The value of a proposition is related to the conceivable alternatives, and writing it down without its context creates the false impression that science progresses by compilation of an increasing list of absolute truths. It does not; the facts and figures pres ented in the following pages have no intrinsic value unless they can be used by the reader to support an argument or point of view. In short, the reader is urged to respond 'So what?' to every item. Secondly, ideas-like other foods-should be date-stamped; science is inseparable from its history. I have set out time-charts to represent the evolution of our understanding in certain areas. I have assumed that the reader is pursuing a course with a content of biochemistry, microbiology and plant science, or has access to basic texts. I have assumed also that common methods such as spectrophotometry, chromatography and electrophoresis, as well as the techniques of mol ecular biology, will be either part of the same course or in active use nearby."

The symposium on "Zinc in Soils and Plants" is the third in a series which began with "Copper in Soils and Plants" in Perth in 1981 and continued with "Manganese in Soils and Plants" in Adelaide in 1988. The symP9sium brings together a series of valuable accounts of many aspects of the reactions of zinc in soils, the uptake, transport and utilization of zinc in plants, the diagnosis and correction of zinc deficiency in plants and the role of zinc in animal and human nutrition. I am grateful for the financial support provided by Grains Research and Development Corporation, Rural Industries Research and Development Corporation, Wool Research and Development Corporation, Ansett Australia, and Qantas Australian. I am most appreciative of the willingness of many scientists to act as referees: G S P Ritchie, R J Gilkes, N C Uren, K Tiller, BLeach, H Greenway, N E Longnecker, J F Loneragan, Z Rengel, C A Atkins, J W Gartrell, P J Randall, D G Edwards, R J Hannam, R J Moir, J E Dreosti, N Suttle, C L White, H Marschner, N Wilhelm, M McBride. All provided valuable comments on the manuscripts. Finally, I thank Mrs M Davison who provided excellent secretarial assistance. A.D. Robson September 1993 Chapter 1.

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.

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.

This proceedings is based on a joint meeting of the two IUFRO (International Union of Forestry Research Organizations) Working Parties, Somatic Cell Genetics (S2.04-07) and Molecular Genetics (S2.04-06) held in Gent, Belgium, 26-30 September, 1995. Although a joint meeting of the two Working Parties had been discussed in the past, this was the first such meeting that became a successful reality. In fact this meeting provided an excellent forum for discussions and interactions in forest bioteclUlology that encouraged the participants to vote for a next joint meeting. In the past decade rapid progress has been made in the somatic cell genetics and molecular genetics of forest trees. In order to cover recent developments in the broad area of biotechnology, the scientific program of the meeting was divided into several sessions. These included somatic embryogenesis, regeneration, transformation, gene expression, molecular markers, genome mapping, and biotic and abiotic stresses. The regeneration of plants, produced by organogenesis or somatic embryogenesis, is necessary not only for mass cloning of forest trees, but also for its application in genetic transformation and molecular biology. Although micropropagation has been achieved from juvenile tissues in a number of forest tree species, in vitro regeneration from mature trees remains a challenging problem in most hardwoods and conifers. The mechanisms involved in the transition from juvenile to mature phase in woody plants are poorly understood. This transition can now be investigated at the molecular level.

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.

This book provides a comprehensive overview of the multiple strategies that plants have developed to cope with drought, one of the most severe environmental stresses. Experts in the field present 17 chapters, each of which focuses on a basic concept as well as the latest findings.

The following major aspects are covered in the book:

. Morphological and anatomical adaptations

. Physiological responses

. Biochemical and molecular responses

. Ecophysiological responses

. Responses to drought under field conditions

The contributions will serve as an invaluable source of information for researchers and advanced students in the fields of plant sciences, agriculture, ecophysiology, biochemistry and molecular biology.

"

Understanding ecosystem structure and function requires familiarity with the techniques, knowledge and concepts of the three disciplines of plant physiology, remote sensing and modelling. This is the first textbook to provide the fundamentals of these three domains in a single volume. It then applies cross-disciplinary insights to multiple case studies in vegetation and landscape science. A key feature of these case studies is an examination of relationships among climate, vegetation structure and vegetation function, to address fundamental research questions. This book is for advanced students and researchers who need to understand and apply knowledge from the disciplines of plant physiology, remote sensing and modelling. It allows readers to integrate and synthesise knowledge to produce a holistic understanding of the structure, function and behaviour of forests, woodlands and grasslands.

Natural and agro-ecosystems are frequently exposed to natural or synthetic substances, which, while they have no direct nutritional value or significance in metabolism, may negatively affect plant functioning. These, xenobiotics, may originate from both natural (fires, volcano eruptions, soil or rock erosion, biodegradation) and anthropogenic (air and soil pollution, herbicides) sources. And, while affected plants have only a limited number of possibilities for avoiding accumulation of these compounds, they do exhibit several enzymatic reactions for detoxification including oxidation, reduction, hydrolysis and conjugation reactions. In agro-ecosystems in particular these mechanisms have great significance in relation to herbicide detoxification and tolerance. In this volume an international group of experts present an overview of the nature and distribution of organic xenobiotics, including their uptake, effects on plant functioning and detoxification mechanisms. The particular significance of glutathione S-transferases in bio-indication and bio-monitoring, and in the detoxification of volatile organic air pollutants and herbicides is evaluated, and their potential significance in phytoremediation and bioaccumulation will be discussed. This volume will be of interest to a wide audience, from graduate students to senior researchers in a wide range of disciplines including plant ecology, plant biochemistry, agriculture and environmental management. It will also be of practical interest to environmentalists, policy makers and resource managers.

Plants offer exciting opportunities to understand major biological questions, i.e. the regulation of development and morphogenesis. How are changes of the environment, developmental cues, and other signals perceived and transduced in physiological responses? What are the elements of plant signalling pathways and what is their organization? The panoply of molecular tools and techniques as well as the blossoming field of plant genetics are providing an exciting ground for major breakthroughs in unravelling the fundamental mechanisms of plant signalling. The present book establishes a state-of-the-art framework spanning the wide spectrum of perception, signal transduction events and transport processes, including cell proliferation and cell cycle regulation, embryogenesis, and flowering. Moreover, the volume emphasizes the role of the major plant signalling substances known to date (the phytohormones and more recently studied substances) and summarizes what we know on their molecular mechanisms of action. The book emphasizes how the use of molecular technology has made plant signalling processes accessible to experimental test.

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."

The highly structured eucaryotic cell with its complex division of biochemical labour requires a distinct protein complement in each cellular structure and compartment. Nuclear coded and cytosolically synthesized polypeptides are specifically sorted to every corner of the cell in a post- or co-translational manner. The presence of separate genomes and protein translation machineries in plastids and mitochondria requires further coordination not only on the transcriptional, translational but also most likely on the protein import level. Numerous different protein transport systems have developed and coexist within plant cells to ensure the specific and selective composition of every sub-cellular compartment. This volume summarizes the current knowledge on protein trafficking in plant cells. Aside from the fundamental aspects in cell biology of how specific pre-protein sorting and translocation across biological membranes is achieved, a major focus is on transport, modification and deposition of plant storage proteins. The increasing use of plants as bioreactors to provide custom-designed proteins of different usage requires detailed understanding of these events. This text is directed not only at students and professionals in plant cell and molecular biology but also at those involved in horticulture and plant breeding. It is intended to serve as a text and guide for graduate-level courses on plant cell biology and as a valuable supplement to courses in plant physiology and development. Scientists in other disciplines who wish to learn more about protein translocation in plants will also find this text an up-to-date source of information and reference.

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).

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.

Plant breeders continue to make significant advances in developing high yield ing, adaptable, disease-free crops. These advances, however, are not realized until an efficient seed production system is in place that rapidly increases geneti cally superior crops and makes them available to the consumer in large quantities at a reasonable cost. Successful seed production requires seed to be genetically pure, free of admixtures, and able to establish rapidly a uniform stand. Seed production is a complex process. Rigorous production criteria are followed by both seed producer and seed companies to ensure that high-quality seed is produced and marketed. These criteria become even more stringent in hybrid seed production. This volume identifies the factors most critical in a successful seed production operation. The fundamental considerations common to all seed crops are established in Part I, Principles of Seed Production. From this founda tion, the practices of seed production are provided in detail in Part II, Seed Production of Specific 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."

This timely reference provides an in-depth and up-to-date study of the most important groups of plant secondary compounds. No other work features such detailed diagrams of the biosynthetic pathways leading to the most important groups of secondary metabolites, as well as the structures of major types of compounds, their distribution in various taxonomic groupings of plants, and the evolutionary and ecological roles of these compounds. Plant Secondary Metabolism presents a basic understanding of the origin of the compounds, the nature of the precursors involved, and the basic reactions, mechanisms, and stereochemistry. The origin of groups of secondary metabolites is linked to evolutionary principles, and their biological activity is viewed in a context of chemical ecology. Topics are treated comprehensively, enabling the reader to understand not only a particular group of compounds, but also how each group fits into the whole. In addition, the text allows readers to systematically survey various secondary metabolites and gain a quick working knowledge which can be applied to problems in a particular field.Those researchers and students who will be most intrigued by this publication's broad overview on plant secondary metabolites come from a diverse range of disciplines, including agronomy, anthropology, biochemistry, biology, botany, chemistry, ecology, entomology, food science, forestry, geology, horticulture, pharmacognosy, plant biology, plant sciences, toxicology, and zoology.

In the field of plant analysis there is a confusing variety of methods and procedures, both for digestions and determinations. In many cases the digestion and the subsequent determination are interrelated. For example, a separate digestion is needed for trace elements in order to obtain determinable concentrations. The authors have chosen a design in which the digestion/extraction procedure is described in one chapter together with all determination procedures that may be carried out on that particular digest/extract. All the necessary information (such as standardizations) appears in appendices. As a consequence, several determination procedures are described two or three times, however, each based on a particular digestion or extraction method. Two types of determination procedure are described: manual and automated. Manual procedures are mainly used in research laboratories, whereas automated procedures are more frequently applied in routine laboratories. Both types of determinations can be used freely, provided that appropriate equipment is available. The determination procedures are only for inorganic components, usually elements. Besides, most procedures are designed to give a total content value of the element under consideration, regardless of the chemical structure in which it occurs in the plant. The Plant Analysis Manual is intended for the practicing (agricultural) chemist.

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."