Like many genetic engineers, I have recently been receiving the atten tion of various venture capital companies, international drug houses and Members of Parliament. I will not discuss which of these approaches are most welcome, but it did cause me to consider the speed of advance in genetic engineering, and the implications of this rapid growth. There were few who anticipated it - only five years ago, most scientists thought applications would come at the end of the century, yet we see products such as insulin and interferon already available for clinical testing. In Europe in general and Britain in particular, this explosive growth in our own field has coincided with a general industrial depression and a marked reduction in funding for biomedical research. The brain drain from Britain is a serious matter, for we are losing the best of our younger scientists, on whom we would rely to train the next generation of molecular biologists. These volumes have come from British labs (mostly because I happen to be based in London, and my contacts and friends are here), and I feel that the quality of the con tributions also shows that our current research is of a high standard.

Genetics and Genomics of Populus provides an indepth description of the genetic and genomic tools and approaches for Populus, examines the biology that has been elucidated using genomics, and looks to the future of this unique model plant. This volume is designed to serve both experienced Populus researchers and newcomers to the field. Contributors to the volume are a blend of researchers, some who have spent most of their research career on Populus and others that have moved to Populus from other model systems. Research on Populus forms a useful complement to research on Arabidopsis. In fact, many plant species found in nature are - in terms of the life history and genetics - more similar to Populus than to Arabidopsis. Thus, the genetic and genomic strategies and tools developed by the Populus community, and showcased in this volume, will hopefully provide inspiration for researchers working in other, less well developed, systems.

The original aim of this book was to cover different aspects of the tradi tionally "filamentous" potex-, carla-, poty-, clostero-, and capilloviruses. The title The Filamentous Plant Viruses seemed the only suitable one, but it has led us to discuss also the quite different filamentous viruses of the rice stripe group-recently officially named the tenuivirus group which otherwise, indeed, might not have been conveniently covered in any volume of this series. The question must be asked: What is there new that justifies the presentation of a book of this kind? An outline of the answer may be Among the traditional filamentous viruses, much pro given as follows. gress has been made in elucidating the physical structure of potexvirus particles, and this work serves as an excellent model for discussion of and future experiments on the poty-, carla-, clostero-, and capilloviruses, which have comparable structures, although they are more difficult to manipulate. Work on the structure and strategy of the genomes of poty viruses is, however, relatively advanced and at a very interesting stage. The helper component that assists the aphid transmission of potyviruses has also recently received considerable attention, although the more we know about that, the less seems clear about the aphid transmission of the carlaviruses and closteroviruses, which apparently neither possess nor require a helper component."

Interest in trees, whether in our streets, parks or forests, has in- creasedconsiderablyin thelast 20 years or so.One reason for this has been the decline and dying of forests, which caused great concern about our environment during the 1980s. Because ofthe prominenceofthis event,which is nowblamedon abiotic factors, it is all too easyto forget that the life oftrees is also affected by a multitude of biotic factors: viruses, bacteria, fungi and animals. These may have very different relationships with trees, but are usually deleterious. The fungi playa particularlyimportant part, and during the course of their evolution they have developed various abilities and strategies in order to obtain nutrients and energy by decomposing wood. On the other hand, the tree has 'learned' to react to external and internal infections. The various interactions between fungi and trees form the main themeofthis book. In reviewing this new book I was involuntarily reminded of a work by Robert Hartig over a century ago, entitled Die Zerset- zungserscheinungen des Holzes der Nadelbiiume und der Eiche in forstlicher, botanischer und chemischer Richtung, which laid the foundation of mycological and pathological research on wood.

This book was developed from the proceedings of the American Chemical Society, Division of Agricultural & Food Chemistry, subdivision of Natural Products Symposium "Biosynthesis and Metabolism of Secondary Natural Products" held in Atlanta, Georgia, April 1991. The objective of the conference was to bring together people from apparently diverse fields, ranging from biotechnology, metabolism, mechanistic organic chemistry, enzymology, fermentation, and biosynthesis, but who share a common interest in either the biosynthesis or the metabolism of natural products. It is our intention to help bridge the gap between the fields of mechanistic bio-organic chemistry and biotechnology. Our thanks go to Dr. Henry Yokoyama, co-organizer of the symposium, the authors who so kindly contributed chapters, the conference participants, and to those who assisted in the peer review process. We also thank the financial supporters of the symposium: ACS/AGFD, NIH General Medical Sciences, and the agricultural, pharmaceutical, biotechnology, and chromatography companies. A full list of the supporting corporations and institutions is given on the following page. Pharma-Tech and P.C., Inc. are manufacturers of instrumentation for high-speed countercurrent chromatography. We thank the Agricultural Research Service and the U. S. Department of Agriculture for granting me permission to co-organize the conference and for us to complete the book. Richard J. Petroski Susan P. McCormick USDA, ARS, National Center for Agricultural Utilization Research Peoria, IL 61604 June 10, 1992 vii CONTENTS ANTIBIOTICS Polyketide Synthetases: Enzyme Complexes and Multifunctional Proteins Directing the Biosynthesis of Bacterial Metabolites from Fatty Acids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . . . . . .

This is an extended version of lectures that were held at the summer workshop Atmosphiirische Umweltforschung im Spannungsfeld zwischen Technik und Natur (At mospheric Environmental Research between Technology and Nature) at the Techni 16, 1996. We were very happy to have Paul J. Crutzen, cal University in Cottbus on July winner of the Nobel Prize for chemistry in 1995, presenting the key lecture on glo bally changing chemistry in the atmosphere. Over the last decades, atmospheric chem istry has been established step by step, not just as an applied discipline of chemistry, but also as a key discipline for our understanding of air pollution, biogeochemical cycling, and climactic processes as well. In fact, the new definition of meteorology as the science of physics and chemistry of the atmosphere expresses this development very well. The chemistry of the atmosphere is strongly influenced by anthropogenic emissions, even on a global scale. As a result of emissions and chemical reactions, the chemical composition of the atmosphere influences the ecosystems directly via depo sition of trace substances, and indirectly by changing the physical climate. Therefore, in this book we combined state-of-the-art lectures describing the physical and chemi cal status of the atmosphere and selected issues representing the interface between atmosphere, technology and nature. Oxidising capacity, heterogeneous processes and acidity still remain as key issues in atmospheric chemistry, even in regions where efficient air control measures have been adopted resulting in reduction of primary atmospheric pollutants."

Genetic material is in flux: this is one of the most exciting recent concepts in molecular biology. This volume of "Plant Gene Research" describes changes that occur in the genetic material of plants. It is worthwhile re membering that the first examples of unstable genomes were described for maize before DNA was known to be the genetic material. Now trans posable elements like the ones found in maize have been described in almost all organisms and have become incorporated into our thinking about genome structure. Flux in the plant genome is not restricted to transposable elements or to nuclear genes. Exchanges of genetic material have been demonstrated within organelle DNA, between organelle DNAs or between organelle and nuclear DNAs. Such exchanges may only occur over evolutionary times or may be a continuing process. Also the environment alters the plant genome. Stress, either viral, nutri tional or tissue-culture induced causes heritable changes in the genome. Infection with the crown gall bacterium Agrobacterium tumefaciens results in the transfer of bacterial DNA into the plant genome."

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

Elms occur, both naturally and cultivated, throughout much of the temperate world. Because of their high tolerance to extreme growing conditions and their widespread distribution, elms have been widely planted in cities, towns and rural areas throughout North America and northern Europe. As such, their current demise due to several pandemics of Dutch elm disease has spurred a huge body of research on breeding for disease resistance, conservation and systematics. The Elms: Breeding, Conservation and Disease Management provides the current state of knowledge in these areas and is an important reference work for pathologists, breeders, taxonomists, and arborists.

In contrast to animals, plants are immobile and, thus, cannot leave a drastically changed environment. Therefore, plants have developped specific strategies involving particular signal and transduction systems as well as a form of cellular organization that allow them to buffer against sudden changes in external conditions. This state-of-the-art summary written by leading scientists deals with: - the most recent data available on the molecular mechanism involved in the response of plant cells to different stimuli; - the critical domaine of ignorance such as the signifi cance of site occupancy of receptors for growth substances; - the estimation of the applicability of new techniques such as electrophysiology, cell imaging and DNA recombinant technology; - directions for future work.

Rhizobia are bacteria which inhabit the roots of plants in the pea family and "fix" atmospheric nitrogen for plant growth. They are thus of enormous economic importance internationally and the subject of intense research interest. Handbook for Rhizobia is a monumental book of practical methods for working with these bacteria and their plant hosts. Topics include the general microbiological properties of rhizobia and their identification, their potential as symbionts, methods for inoculating rhizobia onto plants, and molecular genetics methods for Rhizobium in the laboratory. The book will be invaluable to Rhizobium scientists, soil microbiologists, field and laboratory researchers at agricultural research centers, agronomists, and crop scientists.

Over the past decade the importance of natural resources for sustainable agricultural development has been increasingly discussed at international forums and conferences. Aside from the sustainable management of soil, water, and air, it now seems to be accepted that the sustainable management of genetic resources is one of the four indispensable preconditions for a sustainable agriculture. The discussion on conservation of plant genetic resources for food and agriculture (PGRFA), however, has to reflect the costs of conservation as well. These have not yet been discussed intensively. The study analyzes the conservation costs of plant genetic resources; it also assesses the effectiveness of conservation and the efficiency of the different conservation instruments. It is based on extensive surveys in relevant countries. Following the detailed cost and impact analysis, the results show that the effectiveness of conservation strategies may be increased.

From the beginning of agriculture until about 1950, increased food production came almost entirely from expanding the cropland base. Since 1950, however, the yield per unit of land area for major crops has increased dramatically. Much of the increase in yields was because of increased inputs of energy. Between 1950 and 1985, the farm tractor fleet quadrupled, world irrigated area tripled, and use of fertilizer increased ninefold. Between 1950 and 1985, the total energy used in world agriculture increased 6. 9 times. Irrigation played a particularly important role in the rapid increase in food production between 1950 and 1985. The world's irrigated land in 1950 totaled 94 million hectares but increased to 140 million by 1960, to 198 million by 1970, and to 271 million hectares in 1985. However, the current rate of expansion has slowed to less than 1 % per year. The world population continues to increase and agricultural production by the year 2000 will have to be 50 to 60% greater than in 1980 to meet demands. This continued demand for food and fiber, coupled with the sharp decline in the growth rate of irrigation development, means that much of the additional agricultural production in future years must come from cultivated land that is not irrigated. Agricultural production will be expanded in the arid and semiarid regions because these regions make up vast areas in developing countries where populations are rapidly rising.

The development of powerful new techniques and refmements of tech niques in molecular genetics in recent years, and the surge in interest in biotechnology based on genetic methods, have heralded a new golden age in molecular genetics, and stimulated in diverse disciplines much interest in the technologies themselves and their potential uses in basic and applied biomedical sciences. Although some excellent specialist laboratory manuals (especially the Cold Spring Harbor Laboratory manuals by I. H. Miller; R. W. Davies et al.; and T. Maniatis et al. ) on certain chapters of molecular genetics exist, no general text that covers a broad spectrum of the sub ject has thus far been published. The purpose of this manual is to pre sent most, though of necessity not all of the important methods of molecular genetics, in a series of simple experiments, many of which can be readily accomplished by the microbiologist, biochemist or biotechnologist that has had only limited exposure to genetics. The remainder of the experiments require either greater familiarity with the subject, or guidance by someone with such experience. The book should, therefore, not only enable individuals to acquire new proce dures for ongoing projects, but also serve as a basis for the teaching of molecular genetic techniques in formal predoctoral and postdoctoral laboratory courses."

I first became interested in the methods of planning the sequence and timing of jobs on large-scale development projects, as a field officer involved in planning and implementing mechanised farming schemes in Uganda in the mid-sixties. This interest was reinforced by experience of agro-industrial projects in both Nigeria and Iran, when it became obvious that the lax traditional methods of both planning and controll ing the implementation of agricultural and other rural development projects were very ineffective compared with those already in use in other disciplines. An extended spell as Resident Adviser on a World Bank project to strengthen planning and project management services in the agricultural sector in Sind Province, Pakistan, stimulated this interest further, and gave opportunities to develop the use of improved methods on some very complex schemes. This book summarises the experience gained in adapting critical path methods, well established in other fields, to Third World development projects, with their peculiar problems. It would not have been possible to reach this point without the help and stimulation of discussions with a large number of colleagues, includ ing John Joyce (then of Hunting Technical Services), Hatsuya Azumi (World Bank), and-particularly-Zaffar Sohrwardy and Akhtar Ali of Aarkays Associates in Karachi, during our work together. My thanks are also due to Yasin Mohammed, who typed most of the original draft; Anwar Mohammed and Irene Mills for final typing; and to my wife, Jill, for drawing the original figures.

Completely revised and up-to-date, this wide-ranging, comprehensive treatise examines the many different aspects of vegetables from an international perspective. The diversity and depth of coverage of vegetables is largely due to the extensive background and experiences of the authors, Vincent Rubatzky and Mas Yamaguchi, as well as considerable input from colleagues and expert reviewers. This logically-organized text, filled with numerous illustrations, photographs, and tables, begins with an easy-to-read introduction to such topics as: the current role of vegetables as a world food crop, the origin and classification of vegetables, vegetables in human nutrition, and plant toxicants and folklore concerning vegetables. Background material on the basic principles for growing crops and production under adverse conditions are also featured in this section. Much of the material covered in the book focuses on the major and minor vegetables, their origin, taxonomy, botany, physiology, production and post harvest handling, and composition and use. In addition, current world production statistics are provided for many vegetable crops as well as listings of important diseases, insects, and other pests for many family groups. New features of this edition include: *Three new chapters covering mushrooms, aquatic vegetables, and herbs and spices *several appendix tables listing vegetables according to family, genus, species, nutritive value, and recommended storage conditions for many vegetables The introductory chapter offers an excellent background of the role of vegetables for the beginning and advanced students, both in the U.S. and worldwide. The chapters following provide extension professionals, professors, agricultural agencies, commercial growers, and processing and seed industry personnel with a better understanding of individual vegetable species.

Agroforestry reserach and development in Australia has been largely fragmented and many of the research results have never been published and are unknown. The purpose of this volume is to comprehensively review all of the research that has taken place in the field of agroforestry in Australia, including previously unpublished results, providing readers with the latest technical and economic information about using trees in agriculture for the control of salinity and erosion, for shelter and shade, and for the production of timber, fodder and minor forest products. The book provides information concerning planted trees within all of these categories and includes special review of the management of native vegetation on farms. These papers also examine research needs where appropriate. This book stems from the National Australian Conference on 'The Role of Trees in Sustainable Agriculture' which took place in Albury, Victoria, Australia in October, 1991. Each national review paper is based upon a summary of six or more state review research and development papers, prepared specifically for the national conference. The book thus provides readers with a comprehensive overview of agroforestry rsearch in Australia, which is introduced and summarised in the first chapter.

5 Table 1.1 Continued Species Hosts Families ~-------- ----- X. campestris pv. cassavae Manihot spp. Euphorbiaceae (Wiehe and Dowson 1953) Maraite and Weyns 1979 Cassia tora, C. occidentalis, Cicer Fabaceae X. campestris pv. cassiae arietinum, Pisum sativum (Kulkarni, Patel and Dhande 1951) Dye 1978 Musaceae X. campestris pv. celebensis Musa spp. (Gaumann 1923) Dye 1978 Apiaceae X. campestris pv. centellae Centella asiatica Basnyat and Kulkarni 1979 X. campestris pv. cerealis Agropyron spp., Avena spp., Poaceae Bromus spp., Hordeum spp., (Hagborg 1942) Dye 1978 Secale cereale, Triticum spp. Aegle marmelos, Atalantia spp., Rutaceae X. campestris pv. citri Balsamocitrus paniculata, (Hasse 1915) Dye 1978 Casimiroa edulis, Chaetospermum glutinosa, Citropsis schweinfurthii, Citrus spp. and hybrids, Clausena lansium, Eremocitrus glauca, Evodia spp., Ferollia sPP" Feroniella spp., Fortunella spp., Hesperethusa crellulata, Limonia spp., Melicope triphylla, Microcitrus spp., Murraya exotica, Paramigyna longipedunculata, Poncirus trifoliata and hybrids, Severina buxifolia, Toddalia asiatica, Zanthoxylum spp.

In this book I have collected many reports on the properties of bamboo. Since I started bamboo research in 1974, I have collected many publications on bamboo. However, in contacts with other researchers I became aware of the fact that several of these publications were unknown to them. Consequently their activities in research or in bamboo projects had to start at a lower level than if they had known some of these publications. Therefore, I discussed the need for a book like this with several colleagues, and I decided to start writing. In this book I present data on properties, as published by resear chers. Certainly it is not complete; e.g. the proceedings of the bamboo workshop in Cochin in November 1988 are not included; they arrived just too late to be taken into account. On the other hand, in writing this preface I realize I have forgotten my own thesis. I do apologize to any colleague whose relevant report is not taken into account as well. I like to express my feelings of respect to the board of my faculty: they allowed me to spend so much time on this book, and they gave a considerable financial support for the printing costs."

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."

Large-scale experimentation allows scientists to test the specific responses of ecosystems to changing environmental conditions. Researchers at Oak Ridge National Laboratory together with other Federal and University scientists conducted a large-scale climatic change experiment at the Walker Branch Watershed in Tennessee, a model upland hardwood forest in North America. This volume synthesizes mechanisms of forest ecosystem response to changing hydrologic budgets associated with climatic change drivers. The authors explain the implications of changes at both the plant and stand levels, and they extrapolate the data to ecosystem-level responses, such as changes in nutrient cycling, biodiversity and carbon sequestration. In analyzing data, they also discuss similarities and differences with other temperate deciduous forests. Source data for the experiment has been archived by the authors in the U.S. Department of Energy's Carbon Dioxide Information and Analysis Center (CDIAC) for future analysis and modeling by independent investigators.

A number of well-known forests have been the object of studies by ecological teams. Every ecologist is familiar with the names of forests such as Whytham Woods in England (Elton 1966), Solling in West Germany (Ellenberg 1971), Hubbard Brook in New Hampshire, U. S. A. (Likens et al. 1977, Bormann and Likens 1979), and ladra6s in Central Sweden (Persson 1980). The number of such team studies grew rapidly during the period of the International Biological Programme (Reichle 1981). Each of these forests represented aspects oflocal and general interest. The Niepolomice Forest in Southern Poland (Fig. 1) does not possess any spectacular features and it may be regarded as a typical forest of the lowlands of continental Europe. Situated in the Vistula River Valley, 20 km east of Cracow (50 Degrees07' N, 20 Degrees23' E) it consists of two major sections: an extensive pine forest of the Pino-Quercetum type, and a smaller, deciduous, oak-hornbeam- Fig. 1. The location of the Niepolomice Forest in Southern Poland VI Preface Tilio Carpinetum forest. This huge forested area (11,000 ha) owes its survival in one of the most densely populated parts of Europe to a long period of protection as a royal hunting ground. The period of royal protection ended abruptly at the turn of 20th century under the devastating blows of two world wars followed by perhaps an even greater danger, the effects of modern developments in heavy industry.

The concept of controlled release has attracted increasing attention over the last two decades, with the applications of this technology proliferating in diverse fields in cluding medicine, agriculture and biotechnology. Research and developmental efforts related to controlled release are multiplying in both industry and academia. The reason for this phenomenal growth is obvious. The use of a variety of biologically active agents, such as drugs, fertilizers and pesticides, has become an integral part of modern society. Along with the use of these reagents has evolved an awareness that their uncontrolled application almost inevitably induces harmful effects on the health of humans and their surrounding environments. To eliminate or minimize these harmful effects necessitates the controlled release of these chemicals. Moreover, the controlled release of substances, not usually considered toxic or hazardous, e.g., some catalysts and nutrients, can enhance their effectiveness. The number and variety of controlled release systems, differing in their physical and chemical makeup, are increasing rapidly. Proliferation almost always demands correlation, generalization and unification; it requires both the development of underlying theories of their behavior and the mechanistic interpretation of their performance. This, in turn, requires a statistical and mathematical (quantitative) treatment of the scientific information and technical data pertaining to them. A quantitative treatment can also facilitate the formulation of procedures for computer-aided design of these systems through a priori prediction of their per formance for a variety of design parameters.

A critical companion of zoosemiotics is the first attempt to systematise the study of animal communication and signification through its most important and/or problematic terms and concepts, and its most representative scholars. It is a companion, in that it attempts to cover the entire range of key terms in the field, and it's critical, in that it aims not only to describe, but also to discuss, problematise and, in some cases, resolve, these terms.