T. C. Hutchinson The NATO Advanced Research Workshop detailed in this volume was held in Toronto, Canada, in 1985. The purpose of the Workshop was to provide a "state of the art" report on our knowledge of the sensitivities and responses of forests, wetlands and crops to airborne pollutants. Approximately 40 scientific experts from nine countries participated. Most participants were actively involved in research concerning the effects of air pollutants on natural or agro-ecosystems. These pollutants included acidic deposition, heavy metal particulates, sulphur dioxide, ozone, nitrogen oxides, acid fogs and mixtures of these. Also invited were experts on various types of ecosystem stresses, physiologi cal mechanisms pertinent to acid deposition, and other areas that were felt by the director to be of direct relevance, including: effects of ethylene on vegetation, the physiology of drought in trees, the nature and role of plant cuticles as barriers to acid rain penetration, the use of dendrochronological techniques in reconstructing the time of onset and the subsequent progression of growth declines, the ability of soils to naturally generate acidity, the role of Sphagnum moss in natural peat land acidity, the use of lichens as indicators of changing air quality, and the magnitude of natural emissions of reduced sulphur gases from tropical rainforests and temperate deciduous forests. The Workshop included a series of invited presentations and subsequent group discussions. These presentations were designed to allow syntheses of our present knowledge as well as detailed questioning and discussion."

Can a continuous growth of agriculture be achieved in the sub-Sahara region without inducing irreversible damage to the ecosystem? Until now, doubts have been expressed as to the actual capacity of the soils to sustain a desirable increase of production which can match the requirements of a fast-growing population. Thirty years of investigation and a renewed comprehensive interpretation of research data on soil fertility show that a sustainable agriculture growth could be a practical possibility in a savannah region.

This book provides a quantitative analysis of the role of woody plants in semi-arid regions, for the aSSessment of their benefits in agrosylvopastoralland-use systems with productive and sus tainability objectives. The insights presented and conclusions drawn allow the additional benefits of woody plants for specific climatic and physical site conditions and land-use systems to be estimated. The Sahel and Sudan zones in West Africa, on which the book focusses, represent resource-poor conditions, whose ecological dynamics have been relatively well studied. The role of woody plants in this region, as assessed in this book, is extrapolated to other semi-arid regions, leading to general conclusions on agroforestry's potential as an option for sustainable land use in semi-arid regions. The origins of this book go back to 1982, when the Club du Sahel requested that available data on woody plants in the Sahel region be synthesised, to provide basic information to enable better attention to be given to woody plants in rural development programmes. We are grateful to the Club du Sahel for this challenge. Various people contributed to studies used in this book. The preliminary inventory of the data available was made by Frits Ohler; later his work was continued by Franciska Dekker."

Haploid plants have the gametophytic number of chromosomes. They are of great importance, especially in studies on the induction of muta tions and also for the production of homozygous plants, they are needed in large numbers. The conventional methods employed by plant breeders for their production are cumbersome, time-consuming, laborious and rather inefficient. Sometimes it may take years to produce a pure line. However, with the introduction of in vitro techniques, especially anther culture for the induction of androgenesis, it has become increasingly evi dent that these methods considerably accelerate the production of haploids for plant breeding programs. During the last decade, in vitro-produced haploids have been incor porated into breeding programs of many agricultural crops, and positive results have been obtained especially with rice, wheat, potato, barley, maize, asparagus, sunflower, brassica, tobacco, etc. Among these, rice and wheat are the best examples in which a number of improved varieties have been released. In wheat, the breeding cycle can be shortened by three or four generations when the pollen haploid breeding method is used instead of conventional cross-breeding. The release of the wheat varieties Jinghua 1 and Florin is a typical example of what can be achieved with other crops. Taking these developments into considera tion, the present volume, Haploids in Crop Improvement I, was compil ed.

Most forest tree species were considered recalcitrant a decade ago, but now with the improved in vitro techniques some progress has been made towards culture-of tree species. Micro propagation has been achieved from the juvenile tissues of a number of forest tree species. On the other hand, tissues from most mature trees are still very difficult to grow and differen tiate in vitro. Nevertheless, there has been slow but steady progress in the application of tissue culture technology for culture of tissues, organs, cells and protoplasts of tree species. As compared to most agricultural crops, and herbaceous plant species, trees are a different lot. They have long gene ration cycles. They are highly heterozygous and have a large reservoir of genetic variability. Because of this genetic variability, their response in vitro is also variable. On a single medium, the response of tissues from different trees (genotypes) of a single species may be quite different: some responding by induction of growth and differentiation, while others showing minimal or no growth at all. That makes the somatic cell genetics of woody plants somewhat difficult, but at the same time interesting."

With the emergence of urban and community forestry as the fastest growing part of our pro fession in the last 15 years, the need for a book such as this inevitably developed. The So ciety of American Foresters' urban forestry working group counts 32 or more universities now offering courses in this subject, and the number is growing. For the last several years I have coordinated a continuing education urban forestry course at Rutgers for nonmatriculated students. Registrants have included arborists, shade tree commissioners, landscape architects, city foresters, environmental commissioners, park superintendents, and others whose jobs involve care and management of trees. The course was started by Bob Tate in 1980, around a core of managerial subjects such as in ventories, budgets, and public relations. After Bob left in 1984 to join Asplundh and later to start his own prosperous business in California, the course languished after it exhausted the local market for those subjects.

Modern Methods of Plant Analysis When the handbook Modern Methods of Plant Analysis, was first introduced in 1954, the considerations were: 1. the dependence of scientific progress in biology on the improvement of existing and the introduction of new methods; - 2. the difficulty in finding many new analytical methods in specialized journals which are normally not accessible to experimental plant biologists; 3. the fact that in the methods sections of papers the description of methods is frequently so compact, or even sometimes to incomplete, that it is difficult to reproduce experiments. These considerations still stand today. The series was highly successful, seven volumes appearing between 1956 and 1964. Since there is still today a demand for the old series, the publisher has decided to resume publication of Modern Methods of Plant Analysis. It is hoped that the New Series will be just as acceptable to those working in plant sciences and related fields as the early volumes undoubtedly were. It is difficult to single out the major reasons for the success of any publication, but we believe that the methods published in the first series were up-to-date at the time and presented in a way that made description, as applied to plant material, complete in itself with little need to consult other publications. Contribution authors have attempted to follow these guidelines in this New Series of volumes. Editorial The earlier series of Modern Methods of Plant Analysis was initiated by Michel v.

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."

After the 1988 and 1989 volumes, this is the third volume on Medicinal and Aromatic Plants. Each of the 29 chapters contributed by international scientists deals with one individual plant genus, namely "Atropa," "Ageratina," "Ailanthus," "Aconitum," "Apium," "Aloe," "Akebia," "Bidens," "Carthamus," "Chamomilla," "Carum," "Citrus," "Cymbopogon," "Dysosma," "Euphorbia," "Fritillaria," "Glycyrrhiza," "Lavandula," "Nigella," "Pelargonium," "Perilla," "Podophyllum," "Rosa," "Scutellaria," "Securinega," "Solanum," "Swertia," "Symphytum," "Syringa." Their distribution, economic importance, conventional propagation, in-vitro propagation and production of metabolites through tissue culture are treated in detail. Special emphasis is laid on the potential of industrial in-vitro production of plant compounds of medical and pharmaceutical relevance using tissue culture.

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.

This volume of Advances in Microbial Ecology marks a change in the editor ship of the series. The Editorial Board wishes to take this opportunity to express its gratitude to Martin Alexander, the founding editor and editor of the first five volumes, for his enterprise in establishing the series and in ensuring that Advances has become an outstanding focal point for the identification of new developments in the rapidly expanding field of microbial ecology. With the publication of this volume, we welcome Howard Slater to the Editorial Board. The policies of the Editorial Board remain the same as before. Most con tributions to Advances in Microbial Ecology will be solicited by the Board. However, individuals are encouraged to submit outlines of unsolicited contri butions to the Board for consideration for inclusion in the series. Advances is designed to serve an international audience and to provide critical reviews on basic and applied aspects of microbial ecology. Contributions in the present volume are predominantly concerned with the ecology of aquatic microorganisms, but encompass a variety of approaches to this area. The exception is the chapter by J. W. Doran on the role of micro organisms in the cycling of selenium. G-Y. Rhee discusses the effects of envi ronmental factors on phytoplankton growth. The factors limiting the produc tivity of freshwater microbial ecosystems are considered by H. W. Paerl."

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.

As J understand it, a book Preface is where the author explains to the reader how the book in hand came about, something of the personal reasons for having inflicted such extended duress on one's self to complete the manllscript. and other items that are fit to say but do not fit in the text. This book had its conceptual beginnings in the 1970's wit h my 'studies in scientific synthesis at the North Central Forest Experiment Station, St. Paul, Minnesota. Ours is, clearly, the age of analysis. But, I felt, we must soon begin frameworks for synthesis, or a synthesis would never be possible. In short, I hoped to develop 'interaction' as an integrative principle in forestry. As work progressed on the manuscript, other subthemes developed. First, there was the vague feeling on my part that the forestry profession was losing ground in the contest to see who should manage the forests of the world. This was happening not because foresters do not know how to manage forests in a reasonable manner, but because the public seemed to be loosing faith in the judgement of foresters as professional, responsible, wise land managers. Several well-known incidents of poor judgement in timber harvesting methods on national forests in the United States did little to help the forester's image.

The esculent Lycopersicon esculentum, long thought to be poisonous, has become a major U. S. food crop and source of vitamins and minerals, thanks largely to genetic modification and new production technology Rick (1978) Tomato (Lycopersicon esculentum Mill. ) is one of the most important solana ceous vegetable crops grown worldwide under outdoor and indoor conditions. It has become an important commercial crop so far as the area, production, industrial values and its contribution to human nutrition is concerned. During the past few decades tremendous developments have contributed to the knowledge and understanding of various areas of genetics, breeding and biotechnology and voluminous literature has been generated. The purpose of preparing this monograph is to give a comprehensive up-to-date treatment to the various aspects of genetic improvement of tomato. The emphasis has been placed on cytology, classical and molecular genetics, reproductive biology, germplasm resources, hybrid seed production, use of wild taxa, selection/ breeding methods, breeding for abiotic and biotic stresses, processing and quality breeding, improvement for mechanical harvesting, and biotechnology: tissue culture, protoplast fusion, and genetic transformation. These topics are presented in 22 different chapters. However, a few aspects have been discussed in more than one chapter. For example, seed production is treated in chapters 1, 4 and 8; molecular biology/genetic engineering in chapters 3 and 22 and heterosis in chapters 8 and 16."

Fertilization in mammals normally occUrs within the oviduct, where it is relatively inaccessible to study. However, as a result of painstaking research, most of it carried out over the last five years, this barrier to experimentation has been largely overcome by the development of in vitro fertilization techniques for at least 11 different species, including man. The result has been a rapid increase in our knowledge of the physiological and bio chemical mechanisms involved in the fertilization process. The aim of this book, which is an extension of my recent review of cell surface interactions in fertilization (Gwatkin, 1976), is to present a brief, but well documented, account of the new knowledge that has been attained. Although this book deals with mammalian fertilization mechanisms, I have included some recent experiments on am phibian and invertebrate gametes to supplement the mammalian picture. This information is particularly valuable as the rela tively large number of eggs available from these lower forms has advanced our knowledge of certain fertilization mechanisms beyond what is known in mammals. However, in the interest of brevity, I have omitted details of morphology and minor varia tions between species. For these, and other aspects not covered here, the reader is referred to the books of Austin (1965, 1968), vii viii PREFACE Austin and Short (1972), Metz and Monroy (1969), Monroy (1965), Lord Rothschild (1956a), and Zamboni (l971a)."

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.

r-------------{ Environment (Disease) Fig. 1. A schematic presentation of the interplay between the external environment, pathogen and animal, which influences resistance to infectious disease. Disturbance in equilibrium results in infection and disease skin and the mucous membranes of the respiratory tract. These tissues are in contact with the environment, and direct injury to them facilitate entry of pathogenic microorganisms through these important natural barriers. Sunburn and frostbite are examples of such adverse effects. Climatic factors such as heat and cold may also act as physiological stress factors which affect the specific and non-specific responses of the body to infection. 1.1.2 Pathogen Survival Climatic factors may affect dispersal, spread and survival of pathogenic micro organisms in the environment. This is also true for arthropod vectors such as mosquitos and ticks (Smith 1970; Ferguson and Branagan 1972). The density of the animal population is an important factor determining the concentration of patho gens in the environment. Population density can be influenced by weather condi tions, as animals respond to heat and cold by typical changes in behaviour. For example, in cold weather they tend to huddle together. This behaviour results in increased population density, which in turn involves an increased risk of the spread of airborne infections."

The rapidly growing human population has increased the dependence on fossil fuel-based agrochemicals, such as fertilizers and pesticides, to produce the required agricultural and forestry products. This has exerted great pressure on non-renewable fossil fuel resources, which cannot last indefinitely. Not only do agrochemicals pollute the environment, but pests also become resistant to pesticides. Thus, present agricultural practices exploit natural resources, and damage fauna and flora and agroecosystems. One safe alternative to overcome these problems is the use of allelopathy to sustain development in agriculture and forestry and maintain a clean environment for future generations. This book is the Proceedings of the III International Congress on Allelopathy in Ecological Agriculture and Forestry, held on August 18-21, 1998, at the University of Agricultural Sciences, Dharwad, Karnataka, India, and provides an updated status of current allelopathy research in various leading countries, with the overall aim of developing new technologies for ecological agriculture and forestry in the 21st century. To date, no book on ecological agriculture has discussed these aspects, hence it is the first time that such information is available. The chapter contributors are leading specialists in their fields, and all chapters have been peer-reviewed by international referees. This book will be indispensable for agricultural scientists (agronomists, entomologists, nematologists, plant pathologists, horticulturists, plant breeders, agroforesters, foresters, soil scientists), bioscientists (biochemists, organic chemists, plant ecologists, microbiologists and limnologists), environmentalists, graduate students and farmers, as well as for organizations engaged in sustainable agriculture and organic agriculture.

The anther tapetum, present in all land plants, is a highly specialized, transient tissue surrounding the (micro-)spores and/or pollen grains during their development. Any tapetum malfunction causes male sterility. The exact knowledge of tapetum form and function therefore is indispensable not only for basic research, but also and especially in plant breeding and plant genetics. In fourteen contributions by reknown experts, a comprehensive account of the various characters and functions of the tapetum is provided, covering the areas of cytology, cytophysiology, biochemistry, tapetum development and function.

Fantasies and dreams have their rightful place in science, and sometimes they turn into reality. Regeneration of hybrid plants through protoplast fusion is one such dream come true. In the early 1970s I shared the pioneering excitement in the field of protoplast technology at the Second International Congress of Plant Tissue Culture held in Strasbourg, France. Subsequently, I participated in three international conferences devoted to plant protoplasts, in Salamanca, Spain (1972), Versailles, France (1972), and Nottingham, England (1975). At Versailles Dr. P.S. Carlson presented his work on the successful regeneration of somatic hybrids between Nicotiana glauca and Nicotiana langsdorfii. The enthusi- asm shown by the participants was sufficient indication of the bright future of somatic hybridization. On my return from Versailles, I gathered my thoughts and prepared a concept paper on Potentials of Protoplast Culture Work in Agriculture which was published in Euphytica (Bajaj 1974). The studies on protoplast fusion and somatic hybridization then gained momentum and active work started in many laboratories. Very significant work was done by Melchers et al. (1978) who obtained a somatic hybrid between potato and tomato, calling it "Pomato".

Second in the series, High-Tech and Micropropagation, this work covers the micropropagation of trees and fruit-bearing plants, such as poplar, birches, larch, American sweetgum, black locust, "Sorbus," sandalwood, "Quercus," cedar, Persian walnut, date palm, cocoa, "Citrus," olive, apple, pear, peach, plum, cherry, papaya, pineapple, kiwi, Japanese persimmon, grapevine, strawberry, and raspberry. The importance and distribution of conventional propagation and in vitro studies on individual species are discussed. In particular detail, the transfer of in vitro plants to the greenhouse or the field, and the prospects of commercial exploitation are examined. The book will be of use to advanced students, research workers and teachers in horticulture, forestry and plant biotechnology in general, and also to individuals interested in industrial micropropagation.

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."

No matter what forests are used for, forest managers have to deal with interactions between individual trees and between trees and other forest organisms. To understand these interactions, long-term monitoring of spontaneous forest development is necessary. A complete monitoring system has been developed including a computer package for analysis of long-term observation of forest dynamics. The system's name, "SILVI-STAR," is an acronym of SILVIgenesis and Single-tree Three-dimensional Architecture. A method of nested plot data collection on forest architecture and plant species composition has been developed out for monitoring purposes.

"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.

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).