First attempts to isolate plant genes were for those genes that are abun dantly expressed in a particular plant organ at a specific stage of devel opment. However, many important gene products are produced in a very minute quantity and in specialized cell types. Such genes can now be isolated using a variety of approaches, some of which are described in this volume. The rapid progress during the last decade in regeneration of a number of crop plants and the availability of molecular tools to introduce foreign genes in plants is allowing the engineering of specific traits of agri cultural importance. These genes must, however, be regulated in a spatial and temporal manner in order to have desired effects on plant devel opment and productivity. The habitat of plants necessitate adaptive responses with respect to the environmental changes. Starting from germination of the seed, the plant begins to sense environmental cues such as moisture, light, temperature and the presence of pathogens, and begins to respond to them. Little is known about various signal transduction pathways that lead to biochemical and morphogenetic responses, in particular, transition from vegetative to reproductive phase. With the availability of tools to generate specific mutations via transposon tagging, identification and isolation of genes affecting these processes may be facilitated. Transfer of these genes into heterologous environments will allow understanding of the complex processes that control plant development."

Soil is formed from the physical and chemical weathering of rocks-processes described historically because they involve eons of time-by glaciation, and by wind and water transport of soil materials, later deposited in deltas and loessial planes. Soil undergoes further transformations over time and provides a habitat for biological life and a base for the development of civilizations. Soil is dynamic - always changing as a result of the forces of nature and particularly by the influences of man. Soils have been studied as long as history has been documented. W. H. Gardner told of writings on clay tablets, dating about 1700 Be, in his review, "Early Soil Physics into the Mid-20th Century;' published in Volume 4 of this series. Those writings gave specific instructions on cultivating the soil and seeding crops. Numerous references to soil are found in historical writings, such as Aristotle (384-322 Be), Theophrastus (372-286 Be), Cato the Elder (234-149 Be), and Varro (116-27 Be). Some of the earliest historical refer ences to soil 3000 or more years ago have to do with erosional forces of wind and water. The study of soils today has taken on increased importance because a rapidly expanding population is placing demands on soil that has never before been experienced. Soil scientists have professionally divided themselves into separate disciplines-physics, chemistry, microbiology, mineralogy, genesis, and the like. Studies range from very basic to very applied, and to literally every corner of the earth, and ofthe moon as well."

Ecological Land Classification (ELC) refers to the description of land resources at a range of spatial resolutions (i.e. global to local) and for a range of purposes or values. The emerging science of ELC is in fact a very carefully integrated blend of vegetation and earth sciences, climatology, cartography and ecology with a range of new technologies and methodologies including computer-based geographic information systems, remote sensing and simulation modelling. This publication defines the current state-of-the-art' of ELC. It provides particular insight into the role of ELC in current and future forest resource planning and management, and emphasizes its application and usefulness at various spatial scales, for a variety of geographic locations, and under a range of management scenarios/constraints. The book is an invaluable and substantial reference source about the current trends in ELC and will be of particular value to ecologists, foresters, geographers, resource managers, wildlife biologists, GIS and remote sensing specialists, educators and students.

Volume 10 of Advances in Disease Vector Research consists of seven chapters on vectors that affect human or animal health and six chapters on plant pathogens and their vectors. In Chapter 1, Yasuo Chinzei and DeMar Taylor discuss hormonal regulation of vitellogenesis in ticks. Many blood sucking insects and ticks transmit pathogens by engorgement, which induces vitellogenesis and oviposition in adult animals. To investigate the pathogen transmission mechanism in vector animals, information on the host physiological and endocrinological conditions after engorgement is useful and important because pathogen development or proliferation occurs in the vector hosts at the same time as the host reproduction. Chinzei and Taylor have shown that in ticks, juvenile hormone (JH) is not involved in the endocrinological processes inducing vitellogenin biosynthesis. Synganglion (tick brain) factor(s) (vitellogenesis inducing factor, VIF) is more important to initiate vitellogenesis after engorgement, and ecdysteroids are also related to induction of vitellogenin synthesis. In their chapter, based mainly on their own experimental data, the authors discuss the characterization of main yolk protein, vitellogenin (Vg) , biosynthesis and processing in the fat body, and hormonal regulation of Vg synthesis in tick systems, including ixodid and argasid ticks.

Recently, there has been tremendous progress in the genetic transformation of agricultural crops, and plants resistant to insects, herbicides, and diseases have been produced, field tested and patented. "Transgenic Crops I" compiles this information on cereals, grasses, legumes, and oilseed crops. It is divided into two sections: I. Cereals and Grasses: wheat, rice, maize, barley, sorghum, pearl millet, triticale, "Agrostis" spp., "Cenchrus" "ciliaris," "Dactylis glomerata," "Festuca" "arundinacea," "Lolium" spp., and sugarcane. II. Legumes and Oilseed Crops: "Arachis hypogaea," "Brassica juncea," "Brassica" " napus," " Cicer arietinum," " Glycine" "max," " Gossypium" "hirsutum," " Helianthus annuus," "Lens culinaris," "Linum usitatissimum," "Sinapis alba," "Trifolium," and "Vicia" "narbonensis."
This book is of special interest to advanced students, teachers, and research workers in the field of plant breeding, genetics, molecular biology, plant tissue culture, and plant biotechnology in general.

Heliothis ("Bull worm") species are one of the major pests of field crops worldwide, including sorghum, tomatoes, lettuce, and cotton. Pest problems have intensified over the years as the total area given to agricultural host plants has increased. This comprehensive text, written by experienced researchers, assembles biological and ecological research techniques and approaches to Heliothis management: from the fundamental question of defining genetic species to collecting, rearing, and sampling techniques for the construction of life tables; the measurement of predator impact and physiological development; the detection and measurement of behavior, migration, and diapause; population genetics and resistance. Approaches to modelling population dynamics are also explored. This book is intended for beginning research students as well as experienced workers. It will be a valuable reference for entomologists, population ecologists, and agronomists concerned with crop protection.

Due to the worldwide importance of rice as a crop plant, the biology of rice pests is of great interest to agricultural research. This timely book brings together contributions from the fields of entomology, agronomy, population ecology, and biostatistics to provide a comprehensive survey of rice-insect interaction. Among the topics discussed are - crop loss assessment - economic thresholds and injury levels for incest pests - mosquito leafhoppers and planthoppers population dynamics - pheromone utilization - techniques for predator evaluation - chemical based for insect resistance - applications of tissue culture - systems analysis and - rice pestmanagement. With its emphasis on experimental techniques of pest analysis and control, Rice Insects: Management Strategies will be a valuable reference for researchers and practitioners alike.

The purpose of this volume, the proceedings of the Second Ovarian Workshop, is to review the state of the art in, the field of ovarian follicular and corpus luteum function. This workshop was sponsored by the Center of Population Research, Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland. We also acknowledge the support of The Channing-Weinberg Company, Mr. Henry Burckhardt, The Merck Institute for Experimental Research, The Ortho Pharmaceutical Company, The Expanded Program for Human Reproduction of the World Health Organization, and The University of Miami. We thank the organizing committee consisting of Drs. Hans Lindner, Georgianna Jagiello, Neena Schwartz, Rees Midgley, Gil Greenwald, Andrew Nalbandov, Sheldon Segal, Julia Labotsky, and Griff Ross for their generous assistance in setting up the program. We also thank the chairpersons of each session for their skillful work and for using their expertise in keeping the discussions to the point. We also are grateful to them for editing the written discussions. Chairpersons included Drs. Robert J. Ryan, Roy O. Greep, Allen W. Schuetz, Neena B. Schwartz, John M. Marsh, John W. Wilks, Hans R. Lindner, and Scheldon J. Segal. Special thanks go to all the invited speakers, discussants, participants and particularly Dr. Irving Rothchild for his summing up remarks. The above organization of Ms. Betty Howard and her staff is gratefully acknowledged. The above secretarial assistance of Ms. Gail Williams, Ms. Evelyn Wisowaty, Ms. Theda Smith and Ms.

Dr. Colin J. Schwartz, the scientific editor of this volume, has stated in his preface that this series is based on the needs identified by two scientific conferences, one in Lindau in April of 1970, and the other held in Heidelberg in October of 1973. Since those conferences, numerous data about vascular disease have been accumulated. Even though atherosclerosis remains the major cause of death in industrial countries, evidence in affluent societies points toward a decline in arteriosclerotic death- strokes and myocardial infarction in particular - during recent years. The most prominent example comes from the U. S., but other high-risk regions such as eastern Finland, have also reported a decline. Most likely, this development stems from a change in so called environmental risk factors. Volume II of this handbook deals further with the structure and function of the circulation and con sequently addresses the basic physiological and anatomical elements which are ultimately responsible for the pathological and anatomical changes in the arterial system. While not specifically devoted to the description of disease, this volume nevertheless touches on rele vant pathogenetic and etiologic mechanisms. More than a century ago the pathogenesis of atherosclerosis in its initial phases had been described by VIRCHOW. He made endothe lium the centerpiece of his observations. The morphology of the endothelium and its function playa key role in the manifestations of atherosclerosis. Our knowledge about the function of these cells have yielded important insights."

The world needs for food and fiber continue to increase. Population growth in the developing countries peaked at 2. 4 percent a year in 1965 and has fallen to about 2. I percent. However, in many developing countries almost half the people are under 15 years of age, poised to enter their productive and reproductive years. The challenges to produce enough food for this growing population will remain great. Even more challenging is growing the food in the areas of greatest need. Presently the world has great surpluses of food and fiber in some areas while there are devastating deficiencies in other areas. Economic conditions and the lack of suitable infrastructure for distribution all too often limit the alleviation of hunger even when there are adequate supplies, sometimes even within the country itself. World hunger can only be solved in the long run by increasing crop production in the areas where the population is growing most rapidly. This will require increased efforts of both the developed and developing countries. Much of the technology that is so successful for crop production in the developed countries cannot be utilized directly in the developing countries. Many of the principles, however, can and must be adapted to the conditions, both physical and economic, of the developing countries. This series, Advances in Soil Science.

In the past 10 years, there has been a resurgence in interest in soil management and conservation of the soil resource. With the knowledge we have accumulated in the past 100 years, there is the possibility of developing new and innovative ways of effectively managing the soil. The emphasis on sustainable agriculture requires that we understand how to utilize the soil as a viable living resource. To meet the world demand for food within the next 50 years requires a healthy and strong soil resource which can sustain production. With the dedication of the National Soil Tilth Laboratory in 1989, it was decided that one contribution the laboratory could make to agri cultural science would be to foster an exchange of information on soil management. The focus of that interchange centers on long-term soil management. If we are to fulfill the goals of sustainable agriculture, environmental quality, and feeding the world, there will have to be an increased understanding of how to effectively manage the soil. Long-term soil management requires integrated and interdisciplinary research to bring all of the information together in terms which would be applicable to all soils. To accomplish this goal a workshop is held each year, with the exchange of information focusing on a single topic within the framework of developing effective strategies for long-term soil management. With the forum to focus on an individual theme each year, the theme for the initial workshop was "Limitations to Plant Root Growth."

These Proceedings evolved from the OECD Co-operative Research Programme workshop on "Potential ecological impact of transgenic plants expressing viral sequencies," held at the Agricultural Biotechnology Center in Godollo, Hungary on 24-26 April 1997. The OECD Co-operative Research Programme At the Directorate for Agrieulture of the Organisation for Economie Co-operation and Development (OECD) a co-operative research programme for "Biological Resource Management" has existed since 1990. It foeuses on work in four specific topie areas, one of whieh is "Ecology and utilisation of new organisms" (Theme 3). The activities promoted by this programme are post-doctoral fellowships (announced annually), and the organisation of expert workshops (1-2 workshops per Theme per year). The 26 OECD member countries participating in this programme are: Australia, Austria, Belgium, Canada, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, ltaly, Korea, Japan, the NetherIands, New Zealand, Norway, Poland, Portugal, Spain, Sweden, SwitzerIand, Turkey, the UK, and the USA."

Dendrogeomorphology Beginnings and Futures: A Personal Reminiscence My early forays into dendrogeomorphology occurred long before I even knew what that word meant. I was working as a young geoscientist in the 1960s and early 1970s on a problem with slope movements and deformed vegetation. At the same time, unknown to me, Jouko Alestalo in Finland was doing something similar. Both of us had seen that trees which produced annual growth rings were reacting to g- morphic processes resulting in changes in their internal and external growth p- terns. Dendroclimatology was an already well established field, but the reactions of trees to other environmental processes were far less well understood in the 1960s. It was Alestalo (1971) who first used the term, dendrogeomorphology. In the early 1970s, I could see that active slope-movement processes were affecting the growth of trees in diverse ways at certain localities. I wanted to learn more about those processes and try to extract a long-term chronology of movement from the highly diverse ring patterns.

"Reviews of Environmental Contamination and " "Toxicology"contains timely review articles concerned with all aspects of chemical contaminants (including pesticides) in the total environment, including toxicological considerations and consequences. It attempts to provide concise, critical reviews of advances, philosophy, and significant areas of accomplished or needed endeavor in the total field of residues of these and other foreign chemicals in any segment of the environment, as well as toxicological implications.

Policy issues relating to forestry have been the subject of much debate in recent years, and many countries and international agencies have recently, or are currently in the process, of revising their policies for forestry. Much of this debate has implied that previous policies have failed or been much less successful than had been hoped. There is a tendency to think of policy as a matter for governments, but it is now more widely appreciated that all shareholders in the forestry sector have a legitimate interest in both the policy objectives and the means that will be used to implement it.

This book is mainly concerned with the process of developing policy and the subsequent implementation, than in specific content, though many of the important issues which policies must address are discussed. It is based on a review of many case studies with which the author has been personally involved over the past 40 years.

The European Forest Institute (EFI) has five Research and Development priority ar eas: forest sustainability, forestry and possible climate change, structural changes in markets for forest products and services, policy analysis, and forest sector informa tion services and research methodology. In the area of forest sustainability our most important activity has been the project "Growth trends of European forests," the re sults of which are presented in this book. The project was started in August 1993 under the leadership of Prof. Dr. Heinrich Spiecker from the University of Freiburg, Germany, and it is one of the first EFI's research projects after its establishment in 1993. The main purpose of the project was to analyse whether site productivity has changed in European forests during the last decades. While several forest growth studies have been published at local, re gional and national levels, this project has aimed at stimulating a joint effort in iden tifying and quantifying possible growth trends and their spatial and temporal extent at the European level. Debate on forest decline and possible climate change, as well as considerations re lated to the long term supply of wood underline the importance of this project, both from environmental and industrial points of view. Knowledge on possible changes in growth trends is vital for the sustainable management of forest ecosystems."

This volume contains reviews on five different aspects of bioclimatology: (1) The establishment, maintenance and use of data from automatic weather station networks for agricultural purposes; (2) Techniques for estimating global and ultraviolet irradiance at the earth's surface, and the net radiation balance from operational satellite observations; (3) Mathematical models of the effects of climate on energy and mass balance in crop production; (4) Paleoecological and experimental studies of the response of stomatal density to changes in the atmospheric CO2 concentrations; and (5) The sensory and behavioral responses of insects and other invertebrates to small CO2 gradients resulting from plant and animal metabolism, considering the global changes in CO2 concentration and air temperature.

The study of soils today has taken on increased importance because a rapidly expanding population is placing demands on the soil never before experienced. This has led to an increase in land degradation. Land degradation is one of the most severe problems facing mankind. Volume 11 of Advances in Soil Science was devoted entirely to this critical area of soil science. 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. Until recently, sustainability was seldom, if ever, mentioned in agricultural literature. Now, it is one of the most widely used terms. The high costs ofirriga tion development, escalating energy costs during the 1970s, public concern over potential negative impacts of fertilizer and pesticides on water supplies, soil ero sion, soil compaction and salinity problems, and other concerns have caused many people to question whether many of the present agriculture systems can be sustained. As a result, soil science is beginning to focus more on sustaining the resource base."

PH. BOURDEAU Directorate-General Science. Research and Development. Commission of the European Communities. Brussels. Belgium We are living on a unique planet, the only one in the solar system where life exists. The very existence of life has modified the physical and chemical environment of the earth, its atmosphere and oceans, in a way that makes life sustainable. This system with its complex cybernetic mechanisms has been named GAIA by Lovelock. Man has always interfered with it on a more or less limited scale. This interference is now reaching global proportions such as climate modifications resulting from CO and trace gas 2 accumulation in the atmosphere or the destruction of stratospheric ozone, not to speak of global radioactive contamination. GAIA will probably prevail as a living system but it probably does not give much importance to man's survival as such, and it is man that has to take care of his own survival. In the ecosystem of Planet Earth, soils are the thin interface between lithosphere and atmosphere which constitutes the essential substrate for the terrestrial biosphere, the productivity of which far exceeds that of the oceans, even though the latter cover a much larger area than the continents. Soils themselves are complex systems. They develop through weathering of minerals, are colonised by living organisms which in turn modify their substrate making it suitable for other organisms. This induces a primary ecological succession which eventually reaches a climax, in equilibrium between climate, soil and the biological communities.

Interest and initiatives in agroforestry education and training, as in other aspects of agroforestry development, have increased tremendously during the past decade. Coordination of such educational activities was initiated by the first international workshop on education in agroforestry organized by the International Council for Research in Agroforestry (ICRAF) in Decem ber 1982, at Nairobi, Kenya. Since then, agroforestry has been incorporated into the curricula of many educational and training institutions around the world. Moreover, several institutions have developed entire academic programs specifically in agroforestry. However, most of these activities are still isolated initiatives, without common strategies or philosophies. This second international agroforestry workshop was therefore planned to pro vide a forum for reviewing progress, sharing programs and experiences, and planning and coordinating future directions in agroforestry education and training. The main objectives were to review the on-going programs, to assess the scope of professional education and training in relation to the perceived needs of trained personnel, to recommend guidelines for further program development, and to establish networking among institutions and agencies involved in agroforestry education and training. These proceedings contain the keynote papers, regional/country presenta tions and conclusions and recommendations of the International Workshop on Education and Training in Agroforestry held at the University of Florida, Gainesville, USA in December, 1988. The strategy of the workshop was to facilitate focused discussion on identified issues by an invited group of world leaders in agroforestry education and training."

"Reviews of Environmental Contamination and Toxicology" contains timely review articles concerned with all aspects of chemical contaminants (including pesticides) in the total environment, including toxicological considerations and consequences. It attempts to provide concise, critical reviews of advances, philosophy, and significant areas of accomplished or needed endeavor in the total field of residues of these and other foreign chemicals in any segment of the environment, as well as toxicological implications.

Soil is formed from the physical and chemical weathering of rocks-processes described historically becau'se they involve eons of time-by glaciation and by wind and water transport of soil materials, which are later deposited in deltas and loessial planes. Soil undergoes further transformations over time and provides a habitat for biological life and a base for the development of civilizations. Soil is dynamic-always changing as a result of the forces of nature and particularly by the influences of man. Soil has been studied as long as history has been documented. Numerous references to soil are found in historical writings such as Aristotle (384-322 Be), Theophrastus (372-286 Be), Cato the E1der (234-149 Be), and Varro (116-27 Be). Some of the earliest historical references have to do with the erosional forces of wind and water. The study of soils today has taken on increased importance because a rapidly expanding population is placing demands never before experienced on the soil. This has led to an increase in land degradation. Land degradation is one of the most severe problems facing mankind. Volume 11 of Advances in Soil Science was devoted entirely to this critical area of soil science. This series, Advances in Soil Science, was established to provide a forum for leading scientists to analyze and summarize the available scientific information on a subject, assessing its importance and identifying additional research needs.

Forestry professors used to remind students that, whereas physicians bury their mistakes, foresters die before theirs are noticed. But good institutions live longer than the scientists who contribute to building them, and the half-century of work of the USDA Forest Service's Institute of Tropical Forestry (ITF) is in plain view: an unprecedented corpus of accomplishments that would instill pride in any organization. There is scarcely anyone interested in current issues of tropical forestry who would not benefit from a refresher course in ITF's findings: its early collaboration with farmers to establish plantations, its successes in what we now call social forestry, its continuous improvement of nursery practices, its screening trials of native species, its development of wood-processing technologies appropriate for developing countries, its thorough analysis of tropical forest function, and its holistic approach toward conservation of endangered species. Fortunately, ITF has a long history of information exchange through teaching; like many others, I got my own start in tropical forest ecology fromjust such a course in Puerto Rico. And long before politicians recognized the global importance of tropical forestry, the ITF staff served actively as ambassadors of the discipline, visiting tropical coun tries everywhere to learn and, when invited to do so, to help solve local problems. It is a general principle of biogeography that species' turnover rates on islands are higher than those on continents. Inevitably, the same is true of scientists assigned to work on islands."

''A wealth of information...these two volumes will be immensely valuable to anyone having to deal with this difficult group of compounds.'' ---Biochemical Systematics and Ecology, from a review of Saponins Used in Traditional and Modern Medicine and Saponins Used in Food and Agriculture ''A valuable contribution to the literature.'' ---The Quarterly Review of Biology, December 1997

Over the past decade there has been considerable interest in the effects of atmospheric deposition on forest ecosystems. This volume summarizes the results of the Integrated Forest Study (IFS), one of the most comprehensive research programs conducted. It involved intensive measurements of deposition and nutrient cycling at seventeen diverse forested sites in the United States, Canada, and Norway. The IFS is unique as an applied research project in its complete, ecosystem-level evaluation of nutrient budgets, including significant inputs, outputs, and internal fluxes. It is also noteworthy as a more basic investigation of ecosystem nutrient cycling because of its incorporation of state-of-the-art methods, such as quantifying dry and cloud water deposition. Most significantly, the IFS data was used to test several general hypotheses regarding atmospheric deposition and its effects. The data sets also allow for far-reaching conclusions because all sites were monitored over the same period using comparable instruments and standardized protocols.