Temperate forests cover large areas of Europe and perform a number of important functions such as the regulation of energy and matter, production of wood and other resources, and conservation of biodiversity and habitats; they also have special signi?cance in social and cultural contexts. Initiated in 1960s, the ?rst International Biological Program (IBP) focused on ''the biological basis of productivity and human welfare. '' As the German contribution to the IBP, ecosystem research has been carried out since 1966 in the Solling area (Ellenberg H., Ecological Studies 2, 1971), an upland region in Northwest Germany. This study provided clear evidence that the stability of forest ecosystems was threatened by the high inputs of at- spheric pollutants. This promoted many interdisciplinary research programs which were coordinated by Prof. Dr. Bernhard Ulrich and the Forest Ecosystems Research Center of the University of Go]ttingen. This involved, in addition to the Solling site, the establishment of two other sites for long-term monitoring of ecosystem pro- ] cesses. The two contrasting sites were established in 1980 at Gottinger Wald on base-rich calcareous soil and in 1989 at Zierenberg on volcanic soil. These projects were funded initially by the Federal Ministry of Research and Technology (BMBF) as interdisciplinary projects under the titles: ''Conditions of Stability of Forest Ecosystems'' (1989-1993), and ''Dynamics of Forest Ecos- tems'' (1993-1998). The primary goal of these studies was to quantify the ecolo- cal condition of forests in a changing environment and element ?uxes."

The oil crisis during the 1970s turned interest towards the utilization of renewable resources and towards lignocellulosics in particular. The 1970s were also the cradle period of biotechnology, and the years when biotechnical utilization of lignocellulosic waste from agriculture and forestry gained priori ty. This was a logical conclusion since one of nature's most important biologi cal reactions is the conversion of wood and other lignocellulosic materials to carbon dioxide, water and humic substances. However, while biotechnology in other areas like medicine and pharmacology concerned production of expen sive products on a small scale, biotechnical utilization and conversion of ligno cellulosics meant production of inexpensive products on a large scale. Biotechnical utilization of lignocellulosic materials is therefore a very difficult task, and the commercial utilization of this technology has not progressed as rapidly as one would have desired. One reason for this was the lack of basic knowledge of enzyme mechanisms involved in the degradation and conversion of wood, other lignocellulosics and their individual components. There are also risks associated with initiating a technical development before a stable platform of knowledge is available. Several of the projects started with en thusiasm have therefore suffered some loss of interest. Also contributing to this failing interest is the fact that the oil crisis at the time was not a real one. At present, nobody predicts a rapid exhaustion of the oil resources and fuel production from lignocellulosics is no longer a high priority."

As forests decline in temperate and tropical climates, highly-developed countries and those striving for greater economic and social benefits are beginning to utilize marginal forests of high-latitude and mountainous regions for resources to satisfy human needs. The benefits of marginal forests range from purely aesthetic to providing resources for producing many goods and services demanded by a growing world population. Increased demands for forest resources and amenities and recent warming of high latitude climates have generated interest in reforestation and afforestation of marginal habitats in cold regions. Afforestation of treeless landscapes improves the environment for human habitation and provides for land use and economic prosperity. Trees are frequently planted in cold climates to rehabilitate denuded sites, for the amenity of homes and villages, and for wind shelter, recreation, agroforestry, and industrial uses. In addition, forests in cold climates reduce the albedo of the earth's surface in winter, and in summer they are small but significant long-lived sinks for atmospheric carbon dioxide. Finally, growth and reproductive success of forests at their geographic limits are sensitive indices of climatic change. As efforts to adapt forests to cold climates increase, however, new afforestation problems arise and old ones intensify. Austral, northern, and altitudinal tree limits are determined by many different factors. Current hypotheses for high-latitude tree limits are based on low growing-season temperatures that inhibit plant development and reproduction.

Air pollutants provide environmental conditions that drastically differ in many respects from those to which forest trees are naturally adapted. Leading experts in the field here consider these questions of immediate relevance arising from the changing environment: (1) Do air pollutants introduce effects of selection that differ from those known for populations that are not subject to such stress conditions? (2) If air pollutants introduce quantitatively or even qualitatively novel selective effects, which consequences might arise from the adaptation of forest tree populations to the present conditions as well as for the preservation of adaptability to future conditions? In addition to these questions, concepts for preservation of genetic resources are discussed.

Interdependence between species is a law of nature. The degree of this interdependence is vividly evident in the plant-microbial world. Indeed, there is no axenic plant in nature and one finds various forms of interac tions between these two kingdoms ranging from completely innocuous to obligate parasitic. Most of these interactions are poorly understood at the molecular and physiological levels. Only those few cases for which a molecular picture is emerging are discussed in this volume. With the advent of recombinant DNA technology and the realization that some of these interactions are very beneficial to the host plant, a spate of activity to understand and manipulate these processes is occurring. Microbes interact with plants for nutrition. In spite of the large number of plant-microbe interactions, those microbes that cause harm to the plants (i. e., cause disease) are very few. It is thus obvious that plants have evolved various defense mechanisms to deal with the microbial world. The mecha nisms for protection are highly diverse and poorly understood. Some pathogens have developed very sophisticated mechanisms to parasitize plants, an excellent example for this being crown gall caused by a soil bac terium, Agrobacterium tumefaciens. A remarkable ingenuity is exhibited by this bacterium to manipulate its host to provide nitrogenous compounds which only this bacterium can catabolize. This is carried out by a direct gene transfer mechanism from bacteria to plants."

This book is the first comprehensive description of development of the Acipenserid fish published in the English language. It con tains the results of more than 40 years of studies by the authors and their colleagues. My own life in science has been intimately related both with the authors and the fish, which are the subject of this book. Therefore, it gives me a great pleasure to present to the English reader an expanded version of the book. Those interested in the history of biology must be well aware of the fact that genetics in the USSR was practically demolished by Lysenko at the session of the Lenin All-Union Academy of Agricultural Sciences in 1948. However, it is much less well known that other fundamental branches of biology were also persecuted at that time, experimental embryology (developmental mechanics) among them. As a result, many embryologists, in cluding the authors of this book, were forced to turn to more ap plied problems, this being the only way to continue research. They had to abandon amphibians and concentrate their efforts on sturgeon."

Rice is the most important cereal crop which feeds more than half the population of the world. It is being grown in more than 144. 641 million ha with a production of over 468. 275 million tons (in 1988). Rice is attacked by a large number of pests and diseases which cause an enormous loss in its yield. Therefore, the major objectives in rice breeding are the development of disease resistance, tolerance to insects, adverse soil water, and drought; and improvement of quality including increased protein content. Tremendous efforts being made at the International Rice Research Institute have resulted in the release of improved varieties. It is estimated that the world's annual rice production must increase from 460 million tons (in 1987) to 560 million tons by the year 2000, and to 760 million tons by 2020 (a 65% increase) in order to keep up with the population growth (IRRI Rice Facts 1988). To achieve this gigantic goal, new strategies have to be evolved. Since the success of any crop improvement program de pends on the extent of genetic variability in the base population, new techniques need to be developed not only to generate the much needed variability but also for its conservation. In this regard the progress made in the biotechnology of rice during the last 5 years has amply demonstrated the immense value of innovative approaches for further improvement of this crop.

Charles E. Hess Department of Environmental Horticulture University of California Davis, CA 95616 Research in the biology of adventitious root formation has a special place in science. It provides an excellent forum in which to pursue fundamental research on the regulation of plant growth and development. At the same time the results of the research have been quickly applied by commercial plant propagators, agronomists, foresters and horticulturists (see the chapter by Kovar and Kuchenbuch, by Ritchie, and by Davies and coworkers in this volume). In an era when there is great interest in speeding technology transfer, the experiences gained in research in adventitious root formation may provide useful examples for other areas of science. Interaction between the fundamental and the applied have been and continue to be facilitated by the establishment, in 1951, of the Plant Propagators' Society, which has evolved into the International Plant Propagators' Society, with active programs in six regions around the world. It is a unique organization which brings together researchers in universities, botanical gardens and arboreta, and commercial plant propagators. In this synergistic environment new knowledge is rapidly transferred and new ideas for fundamental research evolve from the presentations and discussions by experienced plant propagators. In the past 50 years, based on research related to the biology of adventitious root formation, advances in plant propagation have been made on two major fronts.

Somatic hybrids through the fusion of plant protoplasts have widened the genetic variability of cultivated plants. As "Somatic Hybridization in Crop Improvement I," published in 1994, this volume describes how this discipline can contribute to the improvement of crops. It comprises 24 chapters dealing with interspecific and intergeneric somatic hybridization and cybridization. It is divided into four sections:
I. Cereals: Barley, rice, and wheat.
II. Vegetables and Fruits: "Arabidopsis," "Asparagus," "Brassica," chicory, "Citrus," "Cucumis," "Diospyros," "Ipomoea," and various Solanaceous species, e.g., tomato, potato, and eggplant.
III. Medicinal and Aromatic Plants: "Atropa," "Dianthus," "Nicotiana," and "Senecio."
IV. Legumes/Pasture Crops: Alfalfa.
This book is tailored to the needs of advanced students, teachers and researchers in the fields of plant breeding, genetic engineering, and plant tissue culture.

The aim of this Handbook is to cover all fields that are necessary for the management of tropical forest resources. It provides proven and/or promis ing concepts, methods and available comparative data. The exten sive references cited are a valuable source for further in-depth research on specific subjects. The handbook is addressed to forestry professionals, natural re source managers and all those interested in the understanding and hand ling of day-to-day problems of tropical forest resources. It is an attempt to present, in a concentrated form, the vast ex perience gathered in tropical forestry. The available knowledge although far from complete, does not permit us to stand idly by when confronted with the dwindling tropical forests. Excuses not to tackle this problem are not acceptable. The experience of the last decades gives us sufficient background to apply techniques and concepts successfully, to encom pass the complexity of the human and the natural tropical environment. The authors responsible for the respective sections have been recom mended by institutions or individuals specialized in the subject. Our thanks go to aH those unnamed individuals whose dedication and responsible work made this handbook a reality. Our gratitude also to all the colleagues who supported the handbook in its early stages by their firm commitment."

Major and exciting changes have taken place recently in various aspects of bio technology and its applications to forestry. Even more exciting is the prospect of major innovations that the entire field of biotechnology holds for plant growth in general. The importance of these developments for the forestry sector is considerable, particu larly since forestry science has not received the kinds of technical and R&D inputs that, say, agriculture has received in the past few decades. Y ct the problems of defor estation as well as stagnation in yields and productivity of existing forests throughout the world are becoming increasingly apparent, with consequences and ecological ef fects that cause growing worldwide concern. Policies for application of existing knowl edge in biotechnology to the field of forestry and priorities for future research and development are, therefore, of considerable value, because it is only through the adop tion of the right priorities and enlightened policies that scientific developments will move along the right direction, leading to improvements in forestry practices through out the world. It was against this backdrop that the Tata Energy Research Institute (TERI) or ganised a major international workshop on the "Applications of Biotechnology in For estry and Horticulture" at New Delhi in January 1988. The present volume covers the proceedings of this international workshop."

Agricultural, natural resource, and environmental problems are becom ing increasingly interdependent. For example, soil erosion is largely determined by agricultural land use. Both water use and water con tamination depend on land use and technology choice in agriculture. In many areas, the fertilizers and pesticides used in agriculture are ma jor pollutants of ground and surface water, having adverse effects on drinking water and fisheries. Agricultural pollutants such as pesticides also produce adverse health effects for agricultural workers and the consuming public. On the other hand, the availability of water resources and the value of competing land uses influence agricultural production. Additionally, regional air quality problems may affect crops and global environmental trends may have long-term implica tions for farming. Agriculture, natural resources and environmental quality are all heavily regulated in the U. S., but they are done so by a vast array of competing or unrelated agencies within the U. S. Departments of Agriculture, Interior, and Commerce, the Environmental Protection Agency; and numerous state agencies. Considering the large number of bureaucratically remote public agencies involved and the pervasive in terdependencies between agriculture, natural resources and the environ ment, policies develop which are at best uncoordinated and at worst conflicting and counterproductive. These policies have become sources of controversy as different interest groups struggle to affect their im plementation, as different agencies have fought for administrative con trol and as legislative bodies have attempted to enact piecemeal changes."

Genetic engineering through DNA recombinants and the in vitro manipulation of isolated protoplasts has recently attracted much atten- tion in agricultural biotechnology, and has greatly advanced during the last 5 years. In an earlier book, Plant Protoplasts and Genetic Engineer- ing I, methods for the isolation, fusion and culture of protoplasts were reviewed and the regeneration of complete plants from isolated pro- toplasts of rice, potato, soybean, linseed, cabbage, chicory, lettuce, but- terbur, orchids, citrus and some other tree species, and interspecific and intergeneric somatic hybrids in Lycopersicon, Petunia, Nicotiana, Solanum, Glycine, Citrus, Brassica, Medicago and Trifolium spp. were discussed. The present volume, Plant Protoplasts and Genetic Engineering II, deals with some of the newer techniques such as microinjections, elec- trofusion, flow cytometry, uptake and integration of DNA, nuclei, iso- lated chromosomes by plant protoplasts and the subsequent regeneration of transgenic plants. The literature on the DNA recombinants and genetic transformation, both Agrobacterium-mediated and direct gene transfer in agricultural crops and trees, such as poplars, is reviewed, and the uses of cytoplasts and miniprotoplasts in genetic manipulation are highlighted.

The aim of this book is to provide an accessible overview for advanced students, resource professionals such as land managers, and policy makers to acquaint themselves with the established science, management practices and policies that facilitate sequestration and allow for the storage of carbon in forests. The book has value to the reader to better understand: a) carbon science and management of forests and wood products; b) the underlying social mechanisms of deforestation; and c) the policy options in order to formulate a cohesive strategy for implementing forest carbon projects and ultimately reducing emissions from forest land use.

Provided here are both underlying theory and recent results concerning the propagation and use of clones in research and in production forestry. State-of-the-art science and case histories treating production, testing, multiplication and deployment of clones are presented. Agroforestry, urban forestry and christmas-tree farming are covered, along with more traditional multiple-use forestry and high-intensity forestry for biomass, wood and fiber production. Clonal forestry is contrasted to the more recent developments of "family forestry," and the classical tree-improvement approach relying on seed-orchards. The history of clonal forestry is covered with reviews of several centuries experience with Sugi in Japan and poplars in Europe. The impacts and use of clones in the contexts of genetic conservation and biodiversity are discussed, as are the laws and regulations affecting clonal production and deployment.

Wild taxa are invaluable sources of resistance to diseases, insects/ pests, nematodes, temperature extremes, salinity and alkalinity stresses, and also of nutritional quality; adaptation; genetic diversity and new species. Utilization of wild relatives of a crop depends largely upon its crossability relations with cultivated varieties. Sev eral wild species are not crossable with the commercial cultivars due to various isolation barriers. Furthermore, in a few cases, hybridiza tion is possible only in one direction and reciprocal crosses are not successful, thus depriving the utilization of desired cytoplasm of many species. However, techniques have been developed to over come many barriers and hybrid plants are produced. New crop species have been developed by overcoming the F 1 sterility and producing amphidiploids and such crops are commercially being grown in the field. The segregation pattern ofF 1 hybrids produced by distant hybridization in segregating generations are different from the intervarietal hybrids. In former cases, generally, unidirectional segregation takes place in early generations and accordingly, selec tion procedures are adopted. In most of the cases, backcross or modified backcross methods have been followed to utilize wild species, and thus numerous types of resistance and other economical attributes have been transferred in the recurrent parents. Protoplast fusion has been amply demonstrated in a number of cases where sexual hybridization was not possible and, as a result, hybrids have been produced."

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.