Studies on the phenomenon of plant pathogenesis (disease development) have been useful to have a deep insight into the interactions between host plant and the pathogen. Depending on the levels of susceptibility (compatibility) or resistance (incompatibility) of the host plant and virulence of the pathogen, disease development may progress, either leading to symptom expression or result in the suppression of pathogen proliferation. Molecular techniques have been applied to elucidate the nature of interactions between the gene products of the plant and pathogen at cellular and molecular levels. Successful evasion of host's surveillance system and subsequent activities of metabolites of the pathogen (enzymes and toxins) encoded by pathogen genes counteracting the effects of various defense-related antimicrobial compounds present already or produced by the host plants, after initiation of infection have been critically studied by applying various molecular techniques. In addition to studying various phases of disease development in individual plants, molecular methods have been demonstrated to be effective, in gathering data on various aspects of epidemiology under natural conditions where the interaction of pathogen with populations of plants is influenced significantly by the environmental conditions existing in different ecosystems. This volume focuses on the possibility of applying the knowledge on pathogenesis and molecular epidemiology to determine the vulnerable stages in the life cycles of the pathogens that can be disrupted to achieve more effective disease control.

This book summarizes the experimental work conducted during a trans-disciplinary research program conducted for six years by the German Research Foundation. Each chapter includes introductory remarks written by internationally recognized scientists in their research areas.

Contributiing authors representing outstanding German scientists from such different disciplines as Physics, Biochemistry, Plant Nutrition, Botany, and Molecular Biology not only report original research but also review the state of knowledge in their fields of research.

The importance of mycorrhiza for the improvement of plant growth is increasingly being realised in Agriculture and Forestry and several mycorrhizal fungi have been commercially recognised for the purpose. The aim of this book is to describe the various techniques used to study the mycorrhizal biology. Problems with preparing such a book are many. Mainly mailing of manuscripts to and from authors resulted in irregular and final editing. Every effort was made not to change the peer review original manuscript to ensure accuracy. Our sole aims is to communicate to the greatest extent possible a current world need in mycorrhizal research. Plant productivity is regulated by microbial associations established in the plant root systems. The interactions of microorganisms and plant roots are especially important in providing nutritional requirements of the plant and the associated microorganisms. Plant growth and development are controlled largely by the soil environment in the root region -rhizosphere. This is a very complex environment in which the effects of the plant on soil microorganisms and the effects of microorganisms on the plant are interacting, interdependent and highly complex. Plant root exudates and breakdown products feed the microbes and the microbe in tum often benefit the plant. Mycorrhizal fungi are important tools for increasing growth, development and yield of economically important plants, they play important role of biofertilizer which can help establish plants in nutrient deficient soils, particularly phosphorus deficient soils, arid, semi-arid and waste lands.

As drought tolerance is a multidirnensional stress, drought tolerance study is a multidisciplinary adventure. In 1992, the network INTERDROUGHT was created with the objective of joining the scientists of the different fields of research involved in drought tolerance study. The network was funded by the EEC and gathered 25 European teams specialized in molecular biology, physiology and geneties. 1\vo workshops were successively organized in 1993 in Sitges (Spain) and in 1994 in Ischia (Italy). After those two European workshops, the necessity of opening the network to the whole scientific community was already clear, and in 1995 the first INTERDROUGHT international conference was held in Montpellier (France). During this meeting, eleven speakers were invited to present a review in their field of research, in a way accessible to all researchers and students, especially those who are not familiar wlth one of the three fields of interest. These eleven reviews are presented in this book. From these reviews three major difficulties arose for drought tolerance irnprovement: - the definition of the drought stress that plants experience; -the differentiation between non adaptive and adaptive response to drought stress; -the identification of the adaptive responses that improved drought yield without decreasing significantly the potential yield. The use of integrated strategies of research will certainly provide irnportant results, such as the recent data obtained on molecular and physiologieal analysis of Arabidopsis mutants.

The sixth International Symposium on Genetics and Molecular Biology of Plant Nutriti9n was held in Elsinore, Denmark from August 17-21, 1998 and organised by th RiS0 National Laboratory in the year of its 40 anniversary. The 98 participants represented 23 countries and 80 scientific contributions with 43 oral and 37 poster presentations. The symposium addressed the molecular mechanisms, physiology and genetic regulation of plant nutrition. The Symposium brought together scientists from a range of different disciplines to exchange information and ideas on the molecular biology of mineral nutrition of plants. The symposium emphasised: * Bridging the gab between molecular biology, applied genetics, plant nutrition and plant breeding. * The development of methodologies to improve the efficiency and effectiveness of nutrition of plants * Quality of plant products. With sessions on: Nitrogen; Phosphorous; Micronutrients; Symbiosis; Membranes; Stress; Heavy Metals and Plant Breeding. In comparison with the previous conferences in this series more emphasis was placed on use of molecular techniques to clarify physiological mechanisms and processes, gene expression and regulation, as well as genetic marker assisted analysis. Significant of molecular genetic markers and other progress was reported in exploitation biotechnologies in breeding programmes.

Bioactive Carbohydrate Polymers is probably the first book dealing with the latest in the field of polysaccharides and related products and their biological activities, especially the immunological effects. The different chapters describe the structure and bioactivity of polysaccharides from plants used in traditional medicine in different parts of the world, especially China, Japan and Europe. The focus of the book is on immunologically active plant and seaweed polysaccharides, pharmacological activities of sulphated polysaccharides of animal and seaweed origin, and on possible activities of polysaccharides in our food. Methods for isolation and characterisation of the polymers with chemical and enzymatic methods is covered, as well as discussions on the different biological test-systems and the information they provide. This book will be useful to scientists and postgraduate students working with polysaccharides and their possible uses, and should be of interest for people working in the areas of chemistry, biology, pharmacy and medicine.

Increased atmospheric nitrogen deposition and changes in the management of heathlands have caused a significant change in the species composition of the NW-European heathlands. This change from ericaceous towards gramineous dominance is analysed in detail in Heathlands: Patterns and Processes in a Changing Environment. Special emphasis is put on the effects of increased atmospheric nutrient input on nutrient cycling, competition between plant species and plant--herbivore interactions. The possibilities for the long-term conservation of heathlands are discussed by considering regeneration from seed and the usefulness of mathematical management models. The book provides a synthesis of pure and applied plant ecology. It is vital reading for plant ecologists, biological conservationists, heathland managers and government decision makers.

The present book provides a comprehensive overview of our current knowledge on plastid biogenesis, plastid-nuclear communication, and the regulation of plastid gene expression at all levels. It also assesses the state-of-the-art in key technologies, such as proteomics and chloroplast transformation. Written by recognized experts in the field, the book further covers crucial post-translational processes in plastid biogenesis and function, including protein processing.

Our image of plants is changing dramatically away from passive entities merely subject to environmental forces and organisms that are designed solely for the accumulation of photosynthate. Plants are revealing themselves to be dynamic and highly sensitive organisms that actively and competitively forage for limited resources, both above and below ground, organisms that accurately gauge their circumstances, use sophisticated cost-benefit analysis, and take clear actions to mitigate and control diverse environmental threats. Moreover, plants are also capable of complex recognition of self and non-self and are territorial in behavior. They are as sophisticated in behavior as animals but their potential has been masked because it operates on time scales many orders of magnitude less than those of animals. Plants are sessile organisms. As such, the only alternative to a rapidly changing environment is rapid adaptation. This book will focus on all these new and exciting aspects of plant biology.

Plants are unique as their development and morphogenesis are plastic throughout their lives. They continuously monitor diverse biotic and abiotic parameters of their environment and these sensory perceptions shape their organs and bodies. Although genes are critical, the final form and architecture of above-ground organs, and es- cially of root systems, are determined by their sensory activities associated with motoric responses (Friml 2003; Hodge 2009). Sensory plant biology and plant el- trophysiology were two lively disciplines until the late 1970s (Bunning 1959; Haupt and Feinleib 1979) but then, for somewhat obscure reasons, they showed no further development. In the last few years, however, there have been numerous advances in plant sciences. These necessitate not just a revival of plant electrophysiology and sensory biology, but also the introduction of plant neurobiology, which includes also plant sensory ecology (Balu ka et al. 2006a; Brenner et al. 2006). First of all, and contrary to all "mechanistic" predictions based on the high turgor pressure of plant cells, endocytosis has been found to be an essential process of plant cells which impinges upon almost all aspects of plant life ( amaj et al. 2005, 2006). Moreover, recent advances in plant molecular biology have identified, besides classic n- rotransmitters, also several proteins typical of animal neuronal systems, such as acetylcholine esterases, glutamate receptors, GABA receptors, and endocannabinoid signaling components, as well as indicating signaling roles for ATP, NO, and re- tive oxygen species (Balu ka et al. 2006b)."

The 18 chapters making up In Vitro Haploid Production in Higher Plants are divided into two sections. Section 1 (eight chapters) covers historical and fundamental aspects of haploidy in crop improvement. Section 2 deals with methods of haploid production, including anther culture, micropore culture, ovary culture, pollination with irradiated pollen, in vitro pollination, and special culture techniques, including polyhaploid production in the Triticeae by sexual hybridization, the influence of ethylene and gelling agents on anther culture, conditional lethal markers, and methods of chromosome doubling.

This volume contains a selection of 14 articles dealing with different aspects of biomonitoring and their relation to questions of global change. During the last 10 - 15 years, vegetation changes due to various causes have been more intensively studied in biological and environmental sciences. Especially aspects of global warming lead to a great variety of tasks for vegetation science (see e.g. the articles by Grabherr, Gottfried & Pauli; Carraro, Gianoni, Mossi, KlOtzli & Walther; Walther; Defila; Stampfli & Zeiter; Rothlisberger; Burga & Perret and Moller, WUthrich & Thannheiser). The different aspects of applied biomonitoring related to (possible) environmental changes concern various ecosystems, e.g. Central European beechwoods, Insubrian evergreen broad-leaved forests, thermophilous lowland deciduous forests, dry grasslands of the lower montane belt of the Ticino Alps, alpine mountain peaks of Switzerland and Austria, Swiss alpine timberline ecotones, and high arctic tundra vegetation. The volume is divided into three parts: A. General aspects of biomonitoring (contributions by KlOtzli; Wildi and Labasch & Otte) , B. Examples of applied biomonitoring in Germany and Switzerland (articles by Hakes; Herpin, Siewers, Kreimes & Markert; Defila; Stampfli & Zeiter; Rothlisberger and Ruoss, Burga & Eschmann), and C. Aspects of global change in the Alps and in the high arctic tundra (Grabherr, Gottfried & Pauli; Burga & Perret; Carraro, Gianoni, Mossi, KlOtzli & Walther; Walther and Moller, WUthrich & Thannheiser).

Since the beginning of agricultural production, there has been a continuous effort to grow more and better quality food to feed ever increasing popula tions. Both improved cultural practices and improved crop plants have allowed us to divert more human resources to non-agricultural activities while still increasing agricultural production. Malthusian population predictions continue to alarm agricultural researchers, especially plant breeders, to seek new technologies that will continue to allow us to produce more and better food by fewer people on less land. Both improvement of existing cultivars and development of new high-yielding cultivars are common goals for breeders of all crops. In vitro haploid production is among the new technologies that show great promise toward the goal of increasing crop yields by making similar germplasm available for many crops that was used to implement one of the greatest plant breeding success stories of this century, i. e., the development of hybrid maize by crosses of inbred lines. One of the main applications of anther culture has been to produce diploid homozygous pure lines in a single generation, thus saving many generations of backcrossing to reach homozygosity by traditional means or in crops where self-pollination is not possible. Because doubled haploids are equivalent to inbred lines, their value has been appreciated by plant breeders for decades. The search for natural haploids and methods to induce them has been ongoing since the beginning of the 20th century."

Af ter a kind mo ti va tion by Judit Si mon (Ed i tor-in-Chief of the Jour nal of Ther mal Anal y s is and Cal o ri m e t r y , Kluwe r Ac a dem ic Pub lis her) and ne go ti a tions with po- si ble con tri bu tors - lasting for m ore than one year - it was de cided to write a book about the ap pli ca tion of ther mal meth ods in bi ol ogy. Its aim was to be a guide how to per form ex per i ments and what kind of in for mation m ight be gained by them. We tried to col lect in for mation tha t could be achieved only dur ing a long per sonal pra- tice. In this way sci en tists from bi ol ogy and med i cine , e. g. , who are not so skilled in phys ics and math e mat ics may re al ize very soon the beauty and power of this tool at one hand. On the other hand, those sci en tists with better back ground in nat u ral sc- ences can be more sensitive to find out exciting biological problems.

A state-of-the-art overview of the intricate functional virus/host relationships that allow a virus or viroid to move cell-to-cell and systemically through the plant, as well as from plant to plant, and, thus, to spread infection. The book also illustrates the mechanisms by which viruses overcome plant defence responses, such as RNA silencing. Arabidopsis is used as an illustration of a plant host eminently suitable for genetic approaches to identify novel players in plant/virus interactions.

Since the beginning of agricultural production, there has been a continuous effort to grow more and better quality food to feed ever increasing popula tions. Both improved cultural practices and improved crop plants have allowed us to divert more human resources to non-agricultural activities while still increasing agricultural production. Malthusian population predictions continue to alarm agricultural researchers, especially plant breeders, to seek new technologies that will continue to allow us to produce more and better food by fewer people on less land. Both improvement of existing cultivars and development of new high-yielding cultivars are common goals for breeders of all crops. In vitro haploid production is among the new technologies that show great promise toward the goal of increasing crop yields by making similar germplasm available for many crops that was used to implement one of the greatest plant breeding success stories of this century, i. e., the development of hybrid maize by crosses of inbred lines. One of the main applications of anther culture has been to produce diploid homozygous pure lines in a single generation, thus saving many generations of backcrossing to reach homozygosity by traditional means or in crops where self-pollination is not possible. Because doubled haploids are equivalent to inbred lines, their value has been appreciated by plant breeders for decades. The search for natural haploids and methods to induce them has been ongoing since the beginning of the 20th century."

Nitrogen is an essential element for plant growth. During the green revolution nitrogenfertilisation was responsible for spectacular yield increases. At present yield is balanced with commitments towards the environment and sustainable agriculture. For agro-biotechnology comprehensive knowledge of plant functioning is needed. Yield improvement and accumulation of essential nitrogen compounds is relying on selection and gene technologies.

Research on the uptake, acquisition and assimilation of nitrogen, as well as the synthesis and storage of reserve and defence N-compounds, therefore, is essential. The third volume in the Plant Ecophysiology series integrates functional and molecular physiology with ecophysiological and sustainable agricultural approaches to get a better understanding of the regulation and the impact of environmental and stress signals on nitrogen acquisition and assimilation. The book is of interest for advanced students and junior researchers and supplies comprehensive information for scientists working in the field of nitrogen metabolism and readers interested in sustainable development.

The beginnings of human civili zation can be traced back to the time , ne- ly 12 ,000 years ago , when th e early humans gradually ch anged from a life of hunting and gathering food , to producing food. This beginning of pri- tive agriculture ensured a dependable supply of food , and fostered the living together of people in groups and the development of s o c i e ty. During th is time, plant s e e ds were recognized a s a valuable s o ur c e of food and nutrition , and began to be used for growing plants for food. Ever s i n c e , plant seeds have played an important role in the development of the human civilization . Even today, s e e ds of a few crop s p e c i e s , s uc h as the cereals and legume s, are the primary s o u r c e of most human food , and the predominant commodity in international agriculture. Owing to their great importance as food for human s and in international trade , seeds have been a favorite object of s t u d y by developmental biologists and physiologi sts , nutritionist s and chem i sts . A wealth of useful information i s available on th e biology of seed s .

In order to understand a process as complex as nitrogen fixation and to be in a position to manipulate it for the benefit of mankind, researchers are now working at the frontiers of science in many different areas: protein structure and function; catalytic mechanisms; electron transfer processes; regulatory circuits and environmental sensing; metabolic integration; chemical communication between organisms; differentiation; genome structure and function; microbial ecology; plant physiology; plant molecular biology; and agronomy. This volume represents a testimony to the advances in nitrogen fixation research that have been made and the contribution of these efforts to the solution of many other varied scientific problems. Limiting steps for future advances are analyzed and new horizons in nitrogen fixation research are proposed.

Actin is an extremely abundant protein that comprises a dynamic polymeric network present in all eukaryotic cells, known as the actin cytoskeleton. The structure and function of the actin cytoskeleton, which is modulated by a plethora of actin-binding proteins, performs a diverse range of cellular roles. Well-documented functions for actin include: providing the molecular tracks for cytoplasmic streaming and organelle movements; formation of tethers that guide the cell plate to the division site during cytokinesis; creation of honeycomb-like arrays that enmesh and immobilize plastids in unique subcellular patterns; supporting the vesicle traffic and cytoplasmic organization essential for the directional secretory mechanism that underpins tip growth of certain cells; and coordinating the elaborate cytoplasmic responses to extra- and intracellular signals. The previous two decades have witnessed an immense accumulation of data relating to the cellular, biochemical, and molecular aspects of all these fundamental cellular processes. This prompted the editors to put together a diverse collection of topics, contributed by established international experts, related to the plant actin cytoskeleton. Because the actin cytoskeleton impinges on a multitude of processes critical for plant growth and development, as well as for responses to the environment, the book will be invaluable to any researcher, from the advanced undergraduate to the senior investigator, who is interested in these areas of plant cell biology.

This volume examines the molecular basis of all aspects of cell division and cytokinesis in plants. It features 19 chapters contributed by world experts in the specific research fields, providing the most comprehensive and up-to-date knowledge on cell division control in plants. The editors are veterans in the field of plant molecular biology and highly respected worldwide.

Oxidation-reduction (i.e. redox) processes at the plasma membrane of any cell have been attracting more and more attention, both in basic and in applied research, since the first workshop dealing with the plasma membrane oxidoreductases was organized in Cordoba, Spain, in 1988. This evolution is evident considering the numerous cell functions performed by plasma membrane redox systems not only in healthy cells but also in cells that escaped from the normal metabolic control (e.g. cancer cells) and cells under attack by pathogens. Plasma membrane redox processes have now been demonstrated to play an essential role in growth control and defense mechanisms of these cells. The great importance of the plasma membrane redox systems originates in the fact that they are located in the membrane which is essentially the site of communication between the living cell and its environment. We may say that the plasma membrane can be considered as the "sensory part" of the cell. No chemical substance can enter the cell interior without interaction with the plasma membrane.

The adv antages of those systems are counterbalanced by some important dis- vantages. For one, in heterotrophic and mixotrophic systems high concentrations of organic ingredients are required in the nutrient medium (particularly sugar at 2% or more), associated with a high risk of microbial contamination. How, and to which extent this can be avoided will be dealt with in Chapter 3. Other disadvantages are the difficulties and limitations of extrapolating results based on tissue or cell c- tures, to interpreting phenomena occurring in an intact plant during its development. It has always to be kept in mind that tissue cultures are only model systems, with all positive and negative characteristics inherent of such experimental setups. To be realistic, a direct duplication of in situ conditions in tissue culture systems is still not possible even today in the 21st century, and probably never will be. The organization of the genetic system and of basic cell structures is, however, essentially the same, and therefore tissue cultures of higher plants should be better suited as model s- tems than, e.g., cultures of algae, often employed as model systems in physiological or biochemical investigations. The domain cell and tissue culture is rather broad, and necessarily unspecif ic. In terms of practical aspects, basically five areas can be distinguished (see Figs. 1.1, 1.2 ), which here shall be briefly surveyed before being discussed later at length.

The importance of haploids is well known to geneticists and plant breeders. The discovery of anther-derived haploid Datura plants in 1964 initiated great excitement in the plant breeding and genetics communities as it offered shortcuts in producing highly desirable homozygous plants. Unfortunately, the expected revolution was slow to materialise due to problems in extending methods to other species, including genotypic dependence, recalcitrance, slow development of tissue culture technologies and a lack of knowledge of the underlying processes. Recent years have witnessed great strides in the research and application of haploids in higher plants. After a lull in activities, drivers for the resurgence have been: (1) development of effective tissue culture protocols, (2) identification of genes c- trolling embryogenesis, and (3) large scale and wide spread commercial up-take in plant breeding and plant biotechnology arenas. The first major international symposium on "Haploids in Higher Plants" took place in Guelph, Canada in 1974. At that time there was much excitement about the potential benefits, but in his opening address Sir Ralph Riley offered the following words of caution: "I believe that it is quite likely that haploid research will contr- ute cultivars to agriculture in several crops in the future. However, the more extreme claims of the enthusiasts for haploid breeding must be treated with proper caution. Plant breeding is subject from time to time to sweeping claims from ent- siastic proponents of new procedures.

Recent years have brought an upsurge of interest in the study of arbuscular mycorrhizal (AM) fungi, partly due to the realization that the effective utilization of these symbiotic soil fungi is likely to be essential in sustainable agriculture. Impressive progress has been made during the last decade in the study of this symbiosis largely as a result of increasing exploitation of molecular tools. Although early emphasis was placed on the use of molecular tools to study physiological processes triggered by the symbiosis, such as expression of symbiosis-specific polypeptides and modulation of host defences, other applications await. It was obvious to us that gathering leaders in the field to summarize these topics and point out research needs was necessary if we were to understand the physiology and function of AM fungi at a molecular level. In addition, we have taken the opportunity to present these reviews in a logical sequence of topics ranging from the initiation of the life cycle of the fungus to its functions in plant growth and in the below ground ecosystem. It was a challenge to limit this flood of information to the confines of one text. This is a very exciting time for mycorrhiza biologists and it is our hope that some of this excitement is conveyed to our readers.