Preservation of nature and the environment has become one of the most important issues of the end of the twentieth century. It has become evident that the methods used for industrial and agricultural production in many countries produce pollutants that cannot undergo natural neutralization by entering the atmosphere, soil or water. Ecosystems that have been developing for centuries are undergoing degradation and what is even more regrettable is that there is an actual threat of profound disorder in the biosphere which could lead to heavy and irreversible changes. Fluorine derivatives are the most aggressive among toxic compounds polluting the atmosphere. Moreover, the percentage of fluorides in industrial emissions is constantly increasing with the bulk of fluorides being emitted by aluminium smelters. Fluorine is poorly detoxified by both plants and animals and the accumulation of even relatively low concentrations over a long period causes a cumulative toxic effect. Among woody plants conifers are less resistant to fluorine. Fluorine derivatives as phytopollutants have been studied less than sulphur compounds, nitrogen oxides, chlorine and hydrogen chloride. It was not until the late 1960s when there was a rapid decline of coniferous forests that researchers directed their attention towards phyto toxic properties of fluorides."

Plants are a major source of medicines, flavors, fragrances, and various pharmaceutical and industrial products. Biotechnology is being put to the service for mass clonal propagation of plants, and to produce impor- tant secondary products in cell cultures. In some cases cell cultures ac- cumulate higher amounts of products than the intact plant cells in situ, and such cultures can be stored through immobilization and cryopreser- vation. An in vitro-produced anti-inflammatory drug, shikonin, has been commercialized, and the recent observations on the increased pro- duction of atropine and hyoscyamine by Agrobacterium rhizogenes- mediated transformed "hairy roots" have encouraged the acceptance of such biotechnologies by the pharmaceutical industry. In an earlier volume, Medicinal and Aromatic Plants I, various aspects of in-vitro culture of cells, bioreactors, micropropagation, im- mobilization, and cryopreservation were discussed. The present volume concerns the application of these biotechnologies to 29 genera of medicinal and aromatic plants. It deals with the distribution, economic importance, conventional propagation, micro propagation, review of tissue culture studies, and the in-vitro production of important medicinal and pharmaceutical compounds in various species of Angelica, Anisodus, Basel/a, Bupleurum, Camellia, Co ix, Coptis, Cryp- tomeria, Datura, Dioscorea, Foeniculum, Gardenia, Geigeria, Heimia, Humulus, Hyoscyamus, Jasminum, Macleaya, Mucuna, Nicotiana, Pimpinel/a, Rauwolfia, Ruta, Salvia, So/anum, Saponaria, Stevia, Tabernaemontana, and Zingiber. The potential role of biotechnology for industrial production is discussed. Biotechnology enables the production and isolation of products of higher purity and also opens the possibility of making desired molecular alterations in products.

Nitrogen is a key element in ecosystem processes. Aspects of local and global changes in nitrogen in both undisturbed and disturbed conditions are discussed. Environmental changes caused by pollution from nitrogenous compounds and changes in landuse are also described. Organisms, plants, animals and microorganisms are all affecting nitrogen supply. Emphasis is placed on natural and anthropogenic transfer of nitrogen between ecosystems and also on the interaction of nitrogen with other bioelements.

th th On June 17 and 18 1987 the fourth workshop on "Azospi rillum: Genetics, Physiology, Ecology" took place at the Uni ver sity of Bayreuth, West Germany, organized by the Genetics depart ment. There were about 80 participants, who came from German research institutions, from other European countries, from Is rael, Egypt, India, North Vietnam, and North and South America. The former workshops had also taken place in Bayreuth, in 1981, 1983 and 1985, hence the organizers could draw on the experience obtained at these earlier workshops. Azospirilla have, during the past 15 years, found an ever increasing scientific interest because, first, these soil bacte ria carry the genetic information for binding molecular nitrogen from the air and, second, they live in close vicinity to the roots of grain crops and forage grasses. By exploitation of these two properties, it is hoped to develop inoculation procedures which can be used in nitrogen-deficient soils.

Most books on epidemiology have treated the subject from a statistical, mathematical or computer applicational point of view. However, experiments must be performed first to provide the data for models which in turn can then be proven by further experimentation. This mutual interplay of theory and empirics gives epidemiology its scientific thrust and charm. This book provides a choice of methods for varying applications and objectives, covering all important aspects for the designing of experiments. Furthermore, the reader is supplied with solutions to his experimental problems and many "tricks of the trade." The newcomer to the field will also profit by this methodology guide.

This volume has been produced for the XI 11th EUCARPIA Congress. EUCARPIA (the European Association for Plant breeding) currently has 1.200 members, including scientists and staff of both publ ic and private organizations. Its aim is to promote scientific and technical research and cooperation In the field of plant breeding, and thereby to contribute to the development of agriculture. Every three years, EUCARPIA organizes a scientific congress. In 1992, the Xilith EUCARPIA Congress will be held In ANGERS (Fran- ce) and the theme Is "Reproductive biology and plant breeding". Reproduction of plant material Is central to selection. The geneti- cist, the plant breeder and the seed grower all use sexual and ve- getative reproduction during the various stages of plant breeding and creation of variety. The possibility of unlimited interspecific reproduction, the use of gametogenesis dysfunction, the creation of auto and allogamy, and the cloning of the best genotypes are the challenges before the plant breeder. To understand how the reproductive system conditions the genetic structure of a population, and to Investigate the relation- ships between the reproductive mode and the organization of varia- bility Is a central key to genetic progress. The articles presented In this book review the current state of knowledge of reproductive biology, and Its impact on variety crea- tion.

Processes of acidification or alkalization of soils are treated, taking the qualitative changes in soil chemistry into consideration. Following a theoretical background of ecosystem proton budgets, the application for assessing external and internal acid loads are demonstrated. The chemistry of organic matter and the oxides of aluminum, iron, and manganese are treated in the context of being sources and sinks for acid loads in soils. Special attention is payed to the assessment of solubility and reaction kinetics of aluminous minerals. The formation of toxic elements in soil solution resulting from the solubilization of inorganic oxides as well as aspects of changes in the nutrient status of soils, changes of fertility and processes leading to a transfer of acidity from soils to surface are discussed.

Behavioural Mechanisms of Food Selection examines animals belonging to diverse trophic groups, from carnivores, herbivores, micro-algal grazers, to filter-feeders and detritus-feeders. In the past Optimal Foraging Theory has been applied to all these groups, but in different ways and in disci plines that rarely overlap. Here concepts and developments hitherto scattered in the literature are drawn together. This uniquely broad synthesis captures the state of the art in the study of diet selection and prescribes new objectives in theoretical development and research.

Root disease epidemics, because much of the activity takes place in soil and out of sight, pose special challenges to growers who seek to manage them and to scientists who study them. All relevant topics of root disease epidemics and their management are presented: The critical aspects of specific disease components including inoculum, host roots, mycorrhiza and the soil environment are explored. Challenges of disease assessment and the temporal and spatial aspects of epidemic development are considered, and approaches to root disease management including host resistance, chemical, biological and cultural management are discussed in detail. The book fulfills the needs of researchers, teachers, and practitioners of plant pathology.

Ecologists are increasingly being drawn into the task of addressing problems of environmental degradation. They are expected to find solutions that will lead to sustainable resource use throughout the world. In doing so, the robustness of the science becomes increasingly important, and the problem of extrapolating the results of research conducted within what is usually a relatively limited geographical scope is increasingly highlighted. One approach to developing a globally robust ecology involves more or less formal intercontinental comparative studies, usually focused on the question of ecological convergence. These studies are directed at testing the prediction that similar physical and other environmental factors in different parts of the world, through their selective influences, will give rise to ecosystems which share com mon structural and functional features. Should this be true, the predictive power of ecology developed within such a framework should be sufficient to solve similar problems elsewhere in such biomes. There is a long history of such an approach in mediterranean type ecosystems, documented in a series of volumes and their accompanying scientific papers beginning with that of Di Castri and Mooney (1973).

"Azospirillum" is a plant growth promoting rhizobacterium used for inoculation of cereal and forage crops. The book covers its physiology, ecology, biochemistry, and molecular biology. The most advanced molecular techniques to understand the regulatory mechanisms of nitrogen fixation and ammonia assimilation, as well as the basis of phytohormone production, are included. In particular, the identification of novel types of promoters, specific regulatory circuits, and new regulatory proteins is described. New insights in the plant growth promoting role of the bacteria through the analysis of their interactions with the plant are presented. Also discussed are field applications, allowing the evaluation of the physiological and agronomic involvement of "Azospirillum" inoculations.

The compartmentation of genetic information is a fundamental feature of the eukaryotic cell. The metabolic capacity of a eukaryotic (plant) cell and the steps leading to it are overwhelmingly an endeavour of a joint genetic cooperation between nucleus/cytosol, plastids, and mitochondria. Alter ation of the genetic material in anyone of these compartments or exchange of organelles between species can seriously affect harmoniously balanced growth of an organism. Although the biological significance of this genetic design has been vividly evident since the discovery of non-Mendelian inheritance by Baur and Correns at the beginning of this century, and became indisputable in principle after Renner's work on interspecific nuclear/plastid hybrids (summarized in his classical article in 1934), studies on the genetics of organelles have long suffered from the lack of respectabil ity. Non-Mendelian inheritance was considered a research sideline ifnot a freak by most geneticists, which becomes evident when one consults common textbooks. For instance, these have usually impeccable accounts of photosynthetic and respiratory energy conversion in chloroplasts and mitochondria, of metabolism and global circulation of the biological key elements C, N, and S, as well as of the organization, maintenance, and function of nuclear genetic information. In contrast, the heredity and molecular biology of organelles are generally treated as an adjunct, and neither goes as far as to describe the impact of the integrated genetic system."

Part A and Part B of the fifth of twelve volumes of The Mycota deal with the mechanisms of interactions between fungi and plants and consider pathogenic as well as mutualistic associations.
Nobody involved in the manipulation of plant populations can afford to ignore the fungi, so pervasive and important are fungus/plant interactions for the well-being of plant communities, both managed and natural. Consequently, these volumes will be of interest to a broad range of professionals involved in agriculture, forestry, horticulture, and conservation as well as plant pathology, mycology, ecology, and evolution.

Integrated control of pests was practiced early in this century, well before anyone thought to call it "integrated control" or, still later, "integrated pest management" (IPM), which is the subject of this book by Mary Louise Flint and the late Robert van den Bosch. USDA entomologists W. D. Hunter and B. R. Coad recommended the same principles in 1923, for example, for the control of boll weevil on cotton in the United States. In that program, selected pest-tolerant varieties of cotton and residue destruction were the primary means of control, with insecticides consid ered supplementary and to be used only when a measured incidence of weevil damage occurred. Likewise, plant pathologists had also developed disease management programs incorporating varietal selection and cul tural procedures, along with minimal use of the early fungicides, such as Bordeaux mixture. These and other methods were practiced well before modern chemical control technology had developed. Use of chemical pesticides expanded greatly in this century, at first slowly and then, following the launching of DDT as a broadly successful insecticide, with rapidly increasing momentum. In 1979, the President's Council on Environmental Quality reported that production of synthetic organic pesticides had increased from less than half a million pounds in 1951 to about 1.4 billion pounds-or about 3000 times as much-in 1977."

Although plant genes were first isolated only some twelve years ago and transfer of foreign DNA into tobacco cells first demonstrated some eight years ago, the application and extension of biotechnology to agricultural problems has already led to the field-testing of genetically modified crop plants. The promise of tailor-made plants containing resistance to pests or diseases as well as many other desirable characteristics has led to the almost compulsory incorporation of molecular biology into the research programs of chemical and seed companies as well as Governmental agricultural agencies. With the routine transformation of rice and the early evidence of transformation of maize the possibility of the world's major cereal crops being modified for improved nutritional value or resistance characteristics is now likely in the next few years. The increasing number of cloned plant genes and the increasing sophistication of our knowledge of the major developmental and biochemi cal pathways in plants should eventually allow us to engineer crop plants with higher yields and with less detrimental impact on the environment than now occurs in our current high input agricultural systems. This book draws together many of the expanding areas of plant molecular biology and genetic engineering that will make a substantial contribution to the development of the more productive and efficient crop plants that the world's farmers will be planting in the next decade."

Tropical and subtropical countries have become well aware of the fact, that they must make better use of their fruits. In spite of the favourable climatic conditions for the production of varieties of delicious fruits in such countries, continuously high tempemtures shorten the shelf-life of most fruits and fruit products. A tropical climate provides ideal conditions for mpid growth of spoilage microorganisms and for chemical reactions. Most of such reactions in fruits and fruit products are deteriomtive in nature causing high respiration rates, texture softening and spoilage of fruit. This causes loss of colour, flavour and vitamins, and browning of fruit products. Even though a fruit product has been rendered microbiolo gically stable, these chemical reactions continue to occur in storage, and they occur much more mpidly in a tropical climate. The processing of fruits and soft drinks is a predominate food industry in tropical and subtropical countries. Some of the large companies in such industries are partly foreign owned. They seem to be efficiently operated with adequate capital, good management, and technological competence, all of which are usually imported from the parent company. However, most of small and medium companies are locally owned, and are deficient in technology and management ability. The products are generally fair. It is rare to find a trained quality assurance manager in these companies. Processing of good fruit products, especially for export, requires sound fruit processing lines as well as good managementthat achieves internationally accept ed standards of quality."

The results, published in this book, present the outcome of a cooperative research between plant ecologists, physiologists and population geneticists. The project received generous financial support from the Foundation for Bio logical Research, which is subsidized by the Netherlands Organization for Scientific Research. During the course of the Project the value of the in tegrative approach on a limited number of Plantago species and populations became evident and it was decided that the results should be published as a book. The start of the preparation of the "plantago" book was done by Dr. P. J. M. van der Aart and Dr. H. Lambers but due to their appointment as full professor of the University of Utrecht they were both unable to continue. We are greatly indebted to Van der Aart and Lambers for the groundwork they have laid. The book presents a sample of results obtained over a period of more than 10 years. Research on Plantago is still continuing, as evident from a number of publications and doctoral theses. We want to thank the authors for their pa tience and assistance to complete the job. The editorial assistance of Mrs. I. Cameron-Doornbos was extremely valuable, as well as the help of Mr. E. Leeuwinga und Mrs. N. Tolmeijer with the drawings and the help of Mrs. T. E. Stuit with the list of references."

Clonal forestry has come of age. Basic techniques in genetics and biotechnology of other organisms are generally applicable to forest trees. However, there are some differences, in particular in the juvenile- and maturation-related regeneration. Examined here are crucial topics of juvenility, maturation and rejuvenation in clonal propagation of trees. In addition, the genetics of clones, population biology of clonal deployment, propagation and field testing of clones, clone identification, clonal physiology, regeneration and variation in plant tissue cultures, the role of somatic embryogenesis in clonal forestry, and recent developments in biotechnology, including the molecular structure of trees and gene transfer are covered in depth.

Global attention in scientific, industrial, and governmental communities to traces of toxic chemicals in foodstuffs and in both abiotic and biotic environ ments has justified the present triumvirate of specialized publications in this field: comprehensive reviews, rapidly published progress reports, and archival documentations. These three publications are integrated and scheduled to pro vide in international communication the coherency essential for nonduplicative and current progress in a field as dynamic and complex as environmental con tamination and toxicology. Until now there has been no journal or other publica tion series reserved exclusively for the diversified literature on "toxic" chemicals in our foods, our feeds, our geographical surroundings, our domestic animals, our wildlife, and ourselves. Around the world immense efforts and many talents have been mobilized to technical and other evaluations of natures, locales, magnitudes, fates, and toxicology of the persisting residues of these chemicals loosed upon the world. Among the sequelae of this broad new emphasis has been an inescapable need for an articulated set of authoritative publications where one could expect to find the latest important world literature produced by this emerging area of science together with documentation of pertinent ancil lary legislation."

Presented here is an analysis of plant development and plant metabolism using the tools of genetics and molecular biology, such as mutant analysis, mutation tagging, mapping using polymorphic characters and basic molecular biology techniques. Studies with a range of model genetic organisms, most notably maize and "Arabidopsis," are included. The reader gains a comprehensive view of the subject which is more and more of both scientific and industrial interest. The value of basic research in plants is highlighted and examples where basic studies have led to applications in agricultural biotechnology are given.

Properly treated sewage effluent becomes an alternative source of irrigation water, and at the same time it provides a convenient means of sewage disposal through land treatment to prevent potential health and environmental hazards caused by uncontrolled flow of wastewater. The objective of this volume is to provide the reader with a comprehensive up-to-date overview of the principles and practices of irrigation with treated sewage effluent, including special reference to arid quality of the water (e.g. pathogenic organisms, salt, nutrients). The present volume describes the main components of effluent-soil-plant systems involved in the development of appropriate irrigation-fertilization-cropping management for optimizing crop production. Comprehensive information has been suggested on the following subjects: 1. source, treatment and properties of sewage effluent; 2. main processes of different effluent constituents on soil-plant systems; 3. irrigation-fertilization management; 4. irrigation systems for sewage effluent.

Legumes and oilseed crops are a rich source of protein and energy. The major objectives in grain-legume breeding are to increase grain yield, protein quantity and quality and digestibility, and to decrease toxic fac- tors, seed hardness and cooking time. Similarly, oilseed crops such as brassicas and peanut share somewhat similar genetic improvement goals, but suffer from susceptibility to a number of pathogens and diseases. In spite of the best efforts through conventional breeding, their yield has been virtually static, with no significant breakthrough. The lack of genetic variability in the base population has been considered to be a major limiting factor for the slow progress made in the improvement of these crops. The desired goals can be achieved by incorporating addi- tional genetic variability in the existing germplasm. The protein and oil contents which are genotypically oriented can be enhanced further by suitable crosses. In this regard, progress made during the last decade, in the area of in vitro manipulation and recombinant DNA technology, holds promise for the improvement of these crops. Among the oilseed crops, Brassica spp. , soybean and sunflower have been well studied, wherein haploids, somaclones, somatic hybrids, cybrids and transformed plants have been produced. Oilpalm is one of the best examples where micropropagation is being commercially prac- ticed. Regarding legumes, though there is extensive work on forages, such as Medicago and Trifolium, much needs to be done on food legumes.

Soils will play a central role in mediating the impact of climate change on natural and managed ecosystems.
The book addresses the various responses of soil processes and properties to environmental change and highlights their contribution to the proper understanding of ecosystem behaviour.
Topics include: Soil hydrology; landscape evolution; salinisation; desertification; soil nitrogen dynamics; soil carbon; soil microbiology; soil erosion; crop modelling.

A year has passed since Eshel Bresler, my good friend and colleague, and a member of the editorial board of the Advanced Series in Agricultural Sciences, died suddenly while on a visit to the Chinese Academy of Sciences in Beijing. We had worked together for almost 30 years at the Institute of Soils and Water, ARO, The Volcani Center at Bet Dagan. At the very beginning of our scientific careers we cooperated directly and as a result one of our first publications was coauthored (Soil Sci. 101:205-209, 1966). Thereafter, our specific research interests diver sified, but we continued to work together, with similar approaches to research, and to strive towards the development of Israel soil science and its integration into general worldwide scientific progress. I don't need to emphasize Eshel's contribution to the understan ding of the processes governing water flow and solute transport pro cesses in soils and unsaturated zones. The contributions to this Volume by such a body of outstanding scientists shows the apprecia tion of the international scientific community to his research achievements."

Starting with the description of meteorological variables in forest canopies and its parameter variations, a numerical three-dimentional model is developed. Its applicability is demonstrated, first, by wind sheltering effects of hedges and, second, by the effects of deforestation on local climate in complex terrain. Scientists in ecology, agricultural botany and meteorology, but also urban and regional lanners will profit from this study finding the most effective solution for their specific problems.