Glutathione is a thiol-containing tripeptide, which appears to be present in nearly all living organisms and which is involved in many important metabolic and physiological processes. The present volume focuses on the biological significance of glutathione in plants. The biochemistry and the metabolism of glutathione are reviewed, and its role in sulphur and selenium metabolism in plants is discussed. The significance of glutathione and of glutathione-related enzymes in the adaptation to natural stress, heavy metals, xenobiotics, air pollution, and in plant-pathogen and plant-animal interactions are evaluated. The main aim of this second volume in the series Plant Ecophysiology is to raise the interest of advanced students and junior researchers in the role of glutathione in plants and to supply basic and comprehensive information for scientists already working on related topics.

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 fermentation of sugar by cell-free yeast extracts was demonstrated more than a century ago by E. Buchner (Nobel Prize 1907). Buchner's observations put an end to previous animistic theories regarding cellular life. It became clear that metabolism and all cellular functions should be accessible to explication in chemical terms. Equally important for an understanding of living systems was the concept, explained in physical terms, that all living things could be cons- ered as energy converters [E. Schroedinger (Nobel Prize 1933)] which generate complexity at the expense of an increase in entropy in their environment. Bioenergetics was established as an essential branch of the biochemical sciences by the investigations into the chemistry of photosynthesis in i- lated plant organelles [O. Warburg (Nobel Prize 1931)] and by the discovery that mitochondria were the morphological equivalent that catalyzed cellular respiration. The ?eld of bioenergetics also encompasses a large variety of ad- tional processes such as the molecular mechanisms of muscle contraction, the structure and driving mechanisms of microbial ?agellar motors, the energetics of solute transport, the extrusion of macromolecules across membranes, the transformation of quanta of light into visual information and the maintenance of complex synaptic communications. There are many other examples which, in most cases, may perform secondary energy transformations, utilizing - ergy stored either in the cellular ATP pool or in electrochemical membrane potentials.

Biological fixation of nitrogen by organisms and associations other than those concerned in the legume-Rhizobium symbiosis has attracted increasing attention since the firstintemationalworkshop on the theme at Piracicaba, Brasil, in 1979. Approximately 150 scientists gathered on September 2-8, 1984, at the Hanasaari Cultural Centre near Helsinki, Finland, for the third international meeting on nitrogen fixation with non-legumes. Forty-two papers and 39 posters were presented; 32 of the papers have been broughttogetherin this publication. The Symposium was generously sponsored by the FinnishNational Fund for Research and Development (SITRA) in connection with a large project on biological nitrogenfixation and utilization ofnitrogen extending from 1980 to 1985. The Symposium was organized jointly by SITRA, which dealt with all practical matters very efficiently and with impressive concern for the welfare of the participants, and Societas Biochemica, Biophysica et Microbiologica Fenniae, the society of Finnish microbiologists, which made valuable contributions on scientific matters. As in the previous symposium at Banff, Canada, in 1982 the programme did not involve parallel sessions~ all participants had the opportunity of listening to all presentations. Consequently, the FIN- NIF Symposium profited from a steady audience and the consistency this gave to the discussions. In view of the growing interest in N-fixation with non-legumes and the continuous broadening of the field, such an arrangement may not be possible in the future. I thank all participants for their contributionsto both oral sessions and poster presentations, and hope that this publication will become a frequently quoted source of knowledge.

In the first part (Part A) of this volume on transport, there was an emphasis on the processes occurring at the membranes bounding the cells. It was convenient to distinguish active and passive processes of transport across the membranes, and to recognize that certain transport processes may be regulated by internal factors in the cells such as cytoplasmic pH, concentrations of ions, of malate or of sugar in the vacuoles, or the hydrostatic pressure. Cells in tissues and organs show the same kinds of properties as individual cells, but in addition there can be cell to cell transport related to the organization of the tissue. Firstly cells within a tissue are separated from the external solutions by a diffusion path comprising parts of the cell walls and intercellular spaces; more generally this extra-cytoplasmic part of the tissue has been called the apoplasm. A similar term is "free space." Secondly, the anatomy of cells in tissues seems to allow some facilitated, local transport between cells in a symplasm. Entry into the symplast and subsequent transport in a symplasmic continuum seems to be privileged, in that ions may not have to mix with the bulk of the cytoplasm and can pass from cell to cell in particular cytoplasmic structures, plasmodesmata. In Chara plants, this kind of transport is found operating across the multi-cellular nodes as the main means of transport between the long internodal cells.

A. POLJAKOFF-MAYBER and J. GALE The response of plants to saline environments is of interest to people of many disciplines. In agriculture the problem of salinity becomes more severe every year as the non-saline soils and the non-saline waters become more intensively and more extensively exploited. Further expansion of agriculture must consider the cultivation of saline soils and the use of water with a relatively high content of soluble, salts. Moreover, industrial development in many countries is causing severe water pollution, especially of rivers, and mismanagement in agriculture often induces secondary salinization of soils and sources of irrigation water. From the point of view of agriculture it is, therefore, of the utmost importance to know the various responses of plants to salinity and to understand the nature of the damage caused by salinity to agricultural crops. Botanists and plant physiologists study plants, their form, growth, metabolism and response to external stimuli. A challenging problem for them is to understand the differences between glycophytes, plants growing in a non-saline environment and halophytes, plants which normally grow in salt marshes, in sea water or in saline soils. This includes the elucidation of structural and functional adaptations which enable halophytes to tolerate the saline environment, and also questions as to whether they only tolerate the saline environment or actually thrive in it. Ecologists and environmentalists are interested in the interrelationships be tween the organism, in this case the plant, and its environment, from the climatic, edaphic and biotic points of view."

The plasma membrane is at once the window through which the cell senses the environment and the portal through which the environment influences the structure and activities of the cell. Its importance in cellular physiology can thus hardly be overestimated, since constant flow of materials between cell and environment is essential to the well-being of any biological system. The nature of the materials mov ing into the cell is also critical, since some substances are required for maintenance and growth, while others, because of their toxicity, must either be rigorously excluded or permitted to enter only after chemical alteration. Such alteration frequently permits the compounds to be sequestered in special cellular compartments having different types of membranes. This type of homogeneity, plus the fact that the wear and tear of transmembrane molecular traffic compels the system to be constantly monitored and repaired, means that the membrane system of any organism must be both structurally complex and dy namic. Membranes have been traditionally difficult to study because of their fragility and small diameter. In the last several decades, however, remarkable advances have been made because of techniques permit ting the bulk isolation of membranes from homogenized cells. From such isolated membranes have come detailed physical and chemical analyses that have given us a detailed working model of membrane. We now can make intelligent guesses about the structural and func tional interactions of membrane lipids, phospholipids, proteins, sterols and water."

As plant physiology increased steadily in the latter half of the 19th century, problems of absorption and transport of water and of mineral nutrients and problems of the passage of metabolites from one cell to another were investigated, especially in Germany. JUSTUS VON LIEBIG, who was born in Darmstadt in 1803, founded agricultural chemistry and developed the techniques of mineral nutrition in agricul ture during the 70 years of his life. The discovery of plasmolysis by NAGEL! (1851), the investigation of permeability problems of artificial membranes by TRAUBE (1867) and the classical work on osmosis by PFEFFER (1877) laid the foundations for our understanding of soluble substances and osmosis in cell growth and cell mechanisms. Since living membranes were responsible for controlling both water movement and the substances in solution, "permeability" became a major topic for investigation and speculation. The problems then discussed under that heading included passive permeation by diffusion, Donnan equilibrium adjustments, active transport processes and antagonism between ions. In that era, when organelle isolation by differential centrifugation was unknown and the electron microscope had not been invented, the number of cell membranes, their thickness and their composition, were matters for conjecture. The nature of cell surface membranes was deduced with remarkable accuracy from the reactions of cells to substances in solution. In 1895, OVERTON, in U. S. A. , published the hypothesis that membranes were probably lipid in nature because of the greater penetration by substances with higher fat solubility.

The first edition of this book was the first to provide an integrated description of sap ascension from an anatomical and functional point of view. The second edition opens with the three-dimensional aspects of wood anatomy. The cohesion-tension theory and new evidence are introduced in response to recent controversies over the mechanism of sap ascent in plants. The physiology, anatomy and biophysics of xylem dysfunction are discussed and new insights into hydraulic architecture are reviewed with special emphasis on physiological limits on maximum transpiration and how hydraulic architecture limits gas exchange, carbon gain and growth of plants. The text concludes with a description of xylem failure and pathology. The book highlights fascinating areas of current research with the aim to stimulate more work in the future.

Root research under natural field conditions is still a step-child of science. The reason for this is primarily methodological. The known methods are tedious, time consuming, and the accuracy of their results is often not very great. Many research workers have been discouraged by doing such root studies. The need for more information on the development and distribution of plant roots in different soils under various ecological conditions is, however, obvious in many ecological disciplines. Especially the applied botanical sciences such as agriculture, horticulture, and forestry are interested in obtaining more data on plant roots in the soil. This book will give a survey of existing methods in ecological root research. Primarily field methods are presented; techniques for pot experiments are described only so far as they are important for solving ecological problems. Laboratory methods for studying root physiology are not covered in this book. Scientific publications on roots are scattered in many different journals published all over the world. By working through the international root literature I found that about ten thousand papers on root ecology have been published at the present. This is not very much compared with the immense literature on the aboveground parts of the plants, but is, however, too much to cite in this book."

This volume presents the proceedings of the Second International Sym posium on Genetic Aspects ofPlant Minerai Nutrition, held in Madison, Wisconsin in 1985. The mechanisms by which plants acquire, transport and utilize essential minerai nutrients are highly complex. The means by which plants either exclude or tolerate ions of metals toxic to plants are equally complex. The first symposium attempted to convene research scientists con cerned with minerai nutrition for the purpose of exploring the kinds of minerai nutrition phenomena identified as being under genetic contro!. The first symposium also placed much emphasis on research to which genetic intervention might be applied. At the second symposium more papers were presented on genetic and breeding research, a long-term objective of the first symposium. The second symposium also included biotic interactions under genetic con trol that either enhanced or impeded ion uptake, e.g. mycorrhizae and nitrogen fixing bacteria. This continuing dialogue is essential for a research area the complexity of which is due to its interdisciplinary nature.

With the demonstration of the "triple response" in plants by Neljubow at the turn of the century, ethylene has been identified as a substance specifically affecting plant growth. Yet it took a few more decades to show that ethylene is a naturally occurring product of plants having all the characteristics of a phytohormone. Ever since much effort has been devoted to a wide variety of physiological and biochemical problems relevant to ethylene. A first meeting was organized in Israel in 1984 to bring together many people active in this rapidly expanding field of experimental research. It is the aim of the present symposium to provide once more a forum at which researchers might expose and comment progress in their work over the last few years. Speakers were invi ted and their contri buti ons ordered ina number of sessions, each of which was centered on a particular topiC. Much of the benefit came from ensuing discussion sessions which were conducted with much competence and expertise by Anderson, Ben-Arie, Goren, Morgan and Osborne. All of these colleagues are recognized leaders in ethylene research today and the organizers owe a very special gratitude to them for their substantial contribution to the programme. It is well to remember the friendly atmosphere, so essential to the success of the whole meeting and so much enjoyed by every partiCipant. Prompt publi ca tion of the papers was made possi ble by the camera-ready procedure offered by the publisher.

Fertilizer is a vital component of strategies for expanding foodproduction. The rapid growth in population and the widening food deficits inmany tropical countries of Asia, Africa, and Latin America call attention to those aspects of fertilization that have been neglected but are expected to yield large economic payoffs in the future. Fertilizer sulfur falls into this category. In the past fertilizer sulfur received little attention from researchers and policymakers since sulfur deficiency was not considered a serious problem. It was not a problem because of low crop yields, extensive cropping, and the incidental supply of sulfur through rain, irrigation water, manures, and sulfurcontaining fertilizers. However, the situation has changed in the last three decades. Moder nagriculture based on high crop yields, intensive cropping, improved crop varieties, and greater use of sulfur-free fertilizers and environmental regula tions restricting sulfur emissions are creating large gaps between sulfur sup ply and sulfur requirements. Sulfur deficiencies are widespread and grow ing. Consequently, the full potential of a modern agricultural system in tropical countries is not being realized. This research effort results from the recognition of the seriousness of the sulfur problem and its adverse impact on food production as well as IFDC's dedication to the development and transfer of economically ef ficient fertilizer technology to tropical countries. This study represents a comprehensive analysis of the technical and economic linkages between fer tilizer sulfur and food production, and it provides guidelines for future directions in fertilizer sulfur research and public policy."

Large regions of the world are regularly burnt either deliberately or naturally. However, despite the widespread occurrence of such fire-prone ecosystems, and considerable body of research on plant population biology in relation to fire, until now there have only been limited attempts at a coherent conceptual synthesis of the field for use by students or researchers.

This book provides an excellent illustration of the interrelationship between progress in scientific methodology and conceptual advances, and its publica tion should contribute to further advances. It is well known that major advances in understanding often follow the development of new methods. The development of the acetylene reduction assay for nitrogenase activity provides a good example of this interrelationship between theory and methods. Theoretical knowledge led to a search for substrates for nitro genase that could be assayed for more easily than ammonium, the normal product of the enzyme. The discovery of the reduction of acetylene to ethylene by nitrogenase provided the ideal answer to the problem by provid ing a rapid, specific, nondestructive, and inexpensive assay for nitrogenase activity. This assay is now used by almost every laboratory doing research on nitrogen fixation. However, further use and development of the acetylene reduction assay has shown that it can underestimate nitrogenase activity and can even give incorrect relative values under some circumstances. The major problem is that exposure of legume nodules to acetylene can cause a large increase in the resistance to oxygen diffusion into the nodule. This reduced supply of oxygen decreases the rate of nitrogenase activity within a few minutes."

The purpose of our present work is to review the fundamental studies on inhibition of soil urease activity and the applied studies on improving efficiency of urea fertilizers by inhibition of soil urease activity. The general literature on these topics covers 65 years, and the patent literature comprises a period of nearly 40 years. Studies related to inhibition of soil urease activity were performed in a great number of countries' well representing all the continents. Full texts of the papers describing these studies were published in one of 18 languages.'. The literature data reviewed are structured into 10 chapters, 81 subchapters, and 224 sections. The bibliographical list consists of 830 papers cited. .In alphabetical order: Argentina, Armenia, Australia, Austria, Belgium, Belorussia, Brazil. Bulgaria, Canada, China, Costa Rica, Cuba. Czech RepUblic, Egypt, Estonia, France, Georgia (Gruzia), Germany, Hungary, India, Iraq, Ireland, Israel, Italy. Japan, Kazakhstan, Lithuania, Malaysia, Moldova, Netherlands, New Zealand, Pakistan, Philippines, Poland, Romania, Russia, Saudi Arabia, Slovakia, South Africa, South Korea, Spain, Sri Lanka. Sudan, Sweden, Thailand, Turkey, Ukraine, United Kingdom, United States of America. Uzbekistan ."

Biologists worldwide now speak the scientific language of molecular biology and use the same molecular tools. Interest is growing in the molecular biology of abiotic stress tolerance and modes of installing better tolerant mechanisms in crop plants. Current studies make plants capable of sustaining their yields even under stressful conditions. Further, this information may form the basis for its application in biotechnology and bioinformatics.

This book reviews all aspects of boron research in recent years and is based on the Third International Symposium on all Aspects of Plant and Animal Boron Nutrition. This includes B sorption mechanisms in soils, deficiency and toxicity of B, B fertilizer application and basic research on the physiology and molecular biology of plant B nutrition, and nutritional function of B in animals and humans.

Plant hormones play a crucial role in controlling the way in which plants grow and develop. While metabolism provides the power and building blocks for plant life, it is the hormones that regulate the speed of growth of the individual parts and integrate them to produce the form that we recognize as a plant.

This book is a description of these natural chemicals: how they are synthesized and metabolized, how they act at both the organismal and molecular levels, how we measure them, a description of some of the roles they play in regulating plant growth and development, and the prospects for the genetic engineering of hormone levels or responses in crop plants. This is an updated revision of the third edition of the highly acclaimed text. Thirty-three chapters, including two totally new chapters plus four chapter updates, written by a group of fifty-five international experts, provide the latest information on Plant Hormones, particularly with reference to such new topics as signal transduction, brassinosteroids, responses to disease, and expansins. The book is not a conference proceedings but a selected collection of carefully integrated and illustrated reviews describing our knowledge of plant hormones and the experimental work that is the foundation of this information.

The Revised 3rd Edition adds important information that has emerged since the original publication of the 3rd edition. This includes information on the receptors for auxin, gibberellin, abscisic acid and jasmonates, in addition to new chapters on strigolactones, the branching hormones, and florigen, the flowering hormone.

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.

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.

With one volume published each year, this series keeps scientists and students current with the latest developments and results in all areas of the plant sciences. This present volume includes insightful reviews covering genetics, cell biology, physiology, comparative morphology, systematics, ecology, and vegetation science.

Lipids in Photosynthesis provides readers with a comprehensive view of the structure, function and genetics of lipids in plants, algae and bacteria, with special emphasis on the photosynthetic apparatus in thylakoid membranes. This volume includes the historical background of the field, as well as a full review of our current understanding of the structure and molecular organization of lipids and their role in the functions of photosynthetic membranes. The physical properties of membrane lipids in thylakoid membranes and their relationship to photosynthesis are also discussed. Other topics include the biosynthesis of glycerolipids and triglycerides; reconstitution of photosynthetic structures and activities with lipids; lipid-protein interactions in the import of proteins into chloroplasts; the development of thylakoid membranes as it relates to lipids; genetic engineering of the unsaturation of membrane glycerolipids, with a focus on the ability of the photosynthetic machinery to tolerate temperature stress; and the involvement of chloroplast lipids in the reactions of plants upon exposure to stress. This book is intended for a wide audience and should be of interest to advanced undergraduate and graduate students and to researchers active in the field, as well as to those scientists whose fields of specialization include the biochemistry, physiology, molecular biology, biophysics and biotechnology of membranes.

Since the first volume on Biophysical Techniques in Photosynthesis Research, published in 1996, new experimental techniques and methods have been devised at a rapid pace. The present book is a sequel which complements the first volume by providing a comprehensive overview of the most important new techniques developed over the past ten years, especially those that are relevant for research on the mechanism and fundamental aspects of photosynthesis.

The contributions are written by leading scientists in their field. The book is divided into 5 sections on Imaging, Structure, Optical and laser spectroscopy, Magnetic resonance and on Theory, respectively. Each chapter describes the basic concepts of the technique, practical applications and some of the scientific results. Possibilities and limitations from a technical as well as a scientific point of view are addressed, allowing the reader not only to recognize the potential of a particular method for his/her own quest, but to assess the resources that are required for implementation.

The primary aim of Wood Structure and Environment is to reveal the hidden ecological richness in stems and roots from trees, shrubs and herbs. The detailed, lucid text will inspire researchers to consider the anatomic microcosm of wood plants and use it as a retrospective source of information, solving problems related to ecophysiology, competition, site conditions, population biology, earth science, wood quality and even human history.