Phospholipidshavelongbeenknownfortheirkeyroleinmaintainingthebilayer structureofmembranesandinphysicallyseparatingthecytosolfromorganelles andtheextracellularspace. Inthepastdecade,acompletelynovelandunexpected functionemerged,full?llingacrucialroleincellsignaling. Itwasthediscoveryin animalcells,thatagonist-activatedcellsurfacereceptorsledtotheactivationofa phospholipase C (PLC), to hydrolyze the minor lipid, phosphatidylinositol 4- bisphosphateintotwosecondmessengers,inositol1,4,5-trisphosphate(InsP)and 3 2+ diacylglycerol(DAG). WhileInsP diffusesintothecytosol,whereitreleasesCa 3 2+ from an intracellular store by activating a ligand-gated Ca -channel, DAG remainsinthemembranetorecruitandactivatemembersoftheproteinkinase Cfamily. Overtheyears,avarietyofotherlipidbased-signalingcascadesweredisc- ered. Theseinclude,phospholipaseA,generatinglyso-phospholipidsandfreefatty acids(tobeconvertedintoprostaglandinsandleukotrienes),phospholipaseD,to generatethelipidsecondmessenger,phosphatidicacid(PA),andphosphoinositide 3-kinase (PI3K), generating a distinct set of polyphosphoinositides (PPI) ph- phorylated at the D3-position of the inositol ring, all with separate signaling functions. Sphingolipids,representinganotherimportantgroupofsignalinglipids, alsocameacross. Themajorityoftheselipid-basedsignalingpathwayshavebeendiscoveredin plantcellstoo. Moreover,theyhavebeenfoundtobeactivatedinresponsetoa widevarietyofbioticandabioticstresssignals,butalsotobebasicallyinvolvedin plantgrowthanddevelopment. Whilemanyoftheenzymes,lipids,andtheirtargets involved arewell conserved, major differences with the mammalian paradigms havealsoemerged. Thisbookhighlightsthecurrentstatusofplantlipidsignaling. Allchaptershave beenwrittenbyexpertsinthe?eldandcoverinformationforbothbeginnersand advancedlipidologists. PartIincludesphospholipases(Chaps. 1-3),partII,lipid kinases (Chaps. 4-7), part III, lipid phosphatases (Chaps. 8-9), part IV, ix x Preface inositolphosphates and PPI metabolism (Chaps. 10-13), part V, PA signaling (Chaps. 14-17),andpartVI,additionallipidsignals,e. g. oxylipins,NAPEand sphingolipids(Chaps18-20). Ithasbeenagreatpleasuretobetheeditorofthis bookandtobeawitnessofthislipid-signalingadventure. Amsterdam,June2009 TeunMunnik Contents PartI Phospholipases PhospholipaseAinPlantSignalTransduction...3 Gu..ntherF. E. Scherer TheEmergingRolesofPhospholipaseCinPlantGrowth andDevelopment...23 PeterE. DowdandSimonGilroy PlantPhospholipaseD...39 WenhuaZhang,XiaoboWan,YueyunHong,WeiqiLi,andXueminWang PartII Kinases Phosphatidylinositol4-PhosphateisRequiredforTip GrowthinArabidopsisthaliana ...65 AmyL. SzumlanskiandErikNielsen PIP-KinasesasKeyRegulatorsofPlantFunction ...79 TillIschebeckandIngoHeilmann PlantPhosphatidylinositol3-Kinase...95 YureeLee,TeunMunnik,andYoungsookLee DiacylglycerolKinase...107 StevenA. AriszandTeunMunnik xi xii Contents PartIII Phosphatases SignalingandthePolyphosphoinositidePhosphatasesfromPlants ...117 GlendaE. Gillaspy PhosphatidicAcidPhosphatasesinSeedPlants...131 YukiNakamuraandHiroyukiOhta PartIV PPIMetabolism InsP inPlantCells ...145 3 YangJuIm,BrianQPhillippy,andImaraYPerera InositolPolyphosphatesandKinases...161 JillStevenson-PaulikandBrianQ. Phillippy PhosphoinositidesandPlantCellWallSynthesis ...175 RuiqinZhong,RyanL. McCarthy,andZheng-HuaYe ImagingLipidsinLivingPlants ...185 JoopE. M. VermeerandTeunMunnik PartV PASignaling PhosphatidicAcid:AnElectrostatic/Hydrogen-BondSwitch?...2 03 EdgarEduardKooijmanandChristaTesterink NitricOxideandPhosphatidicAcidSignalinginPlants...223 AyelenM. Diste'fano,M. LucianaLanteri,ArjentenHave, CarlosGarc?'a-Mata,LorenzoLamattina,andAnaM. Laxalt 3-Phosphoinositide-DependentProteinKinaseisaSwitchboard fromSignalingLipidstoProteinPhosphorylationCascades...243 ChristineZalejskiandLa'szlo'Bo..gre PartVI AdditionalLipidSignals DiacylglycerolPyrophosphate,ANovelPlantSignalingLipid...263 EmmanuelleJeannette,SophieParadis,andChristineZalejski OxylipinSignalingandPlantGrowth...277 AlinaMosblech,IvoFeussner,andIngoHeilmann Contents xiii FattyAcidAmideHydrolaseandtheMetabolismof N-AcylethanolamineLipidMediatorsinPlants...293 KentD. ChapmanandElisonB. Blanca?or SphingolipidSignalinginPlants...307 LouiseV. MichaelsonandJohnathanA. Napier Index ...323 Contributors Steven A. Arisz Section Plant Physiology, Swammerdam Institute for Life Sciences,UniversityofAmsterdam,SciencePark904,NL-1098XH,Amsterdam, TheNetherlands ElisonB. Blanca?or SamuelRobertsNobleFoundation,PlantBiologyDivision, Ardmore,OK73401,USA,eblanca?or@noble.

Plant Molecular Biology Manual (Second Edition) is an entirely new manual containing both fundamental and recently described techniques in the area of plant molecular biology. Designed for use in the research laboratory, the Plant Molecular Biology Manual presents detailed techniques in the areas of plant transformation, recombinant DNA and other nucleic acid manipulations, nuclear run-on and in vitro transcription systems, in situ hybridization and immunodetection systems, protein-nucleic acid interaction analyses, subcellular targeting of proteins in the plant cell, and gene tagging using T-DNA and transposons. This second edition contains more than 40 newly written chapters, including descriptions of subjects such as virus-mediated gene transfer, specialized Agrobacterium strains and T-DNA vectors, nuclear run-on and in vitro transcription systems, non-radioactive detection systems, characterization of transcription factors, nuclear protein targeting, and T-DNA and transposon mutagenesis, not previously described in the first edition.

It is appropriate at this time to reflect on two decades of research in biological control of weeds with fungal plant pathogens. Some remarkable events have occurred in the last 20 years that represent a flurry of activity far beyond what could reasonably have been predicted. In 1969 a special topics review article by C. L. Wilson was published in Annual Reviews of Phytopathology that examined the literature and the potential for biological control of weeds with plant pathogens. In that same year, experiments were conducted in Arkansas that determined whether a fungal plant pathogen could reduce the infestation of a single weed species in rice fields. In Florida a project was under way to determine the potential use of a soil-borne plant pathogen as a means for controlling a single weed species in citrus groves. Work in Australia was published that described experiments that sought to determine whether a pathogen could safely and deliberately be imported and released into a country to control a weed of agricultural importance. All three projects were successful in the sense that Puccinia chondrillina was released into Australia to control rush skeleton weed and was released later into the United States as well, and that Colletotrichum gloeosporioides f.sp. aeschynomene and Phytophthora palmivora were later both marketed for the specific purpose of controlling specific weed species.

With one volume each year, this series keeps scientists and advanced students informed of the latest developments and results in all areas of the plant sciences.

This book is addressed to all biologists seeking a review of the various transport processes of minerals and organic substances in plants from the level of cell organelles to the longer-distance movements in the largest trees. It is directed toward students having had some elementary physiol ogy, but the attempt has been made to provide information of interest on the frontiers of current research. Doing this comprehensively, we wished to consider all of the points of view that appeared to be important; on the other hand, space and time were limited. Therefore, the presentation had to strike an intermediate ground between the style of a textbook giving of selected problems and a comprehensive ref representative treatments erence book covering all ramifications. The reader will notice that the pendulum will swing more toward one and then to the other. We did not want to avoid, and we felt it was not appropriate to neglect completely our own special research interests, which led to some emphasis on certain SUbjects. The immediate origin ofthe book is the Heidelberger Taschenbuch 125 (HTB 125) Stojjtransport der Pflanzen by U. L. (1973), which in turn was preceded by an earlier work, Aktiver Transport: Kurzstreckentransport bei Pflanzen Protoplasmatologia vol. VIII17 b by U. L. (1969). At the Li verpool Workshop on Ion Transport in 1972 organized by W. Peter An derson, and while in a jovial and expansive mood, the authors agreed to produce an English version."

Annual desert plant species of unrelated taxa in the Negev Desert of Israel have developed complementary sets of adaptations and survival strategies as ecological equivalents with physiological, morphological and anatomical resemblances, in the various stages of their life cycles. After 40 years of research in hot deserts Yitzchak Gutterman provides a comprehensive treatise of such adaptations and strategies. In doing so he covers the following topics: post-maturation primary seed dormancy, which prevents germination of maturing seeds before the summer; seed dispersal mechanisms with escape or protection strategies; cautious or opportunistic germination strategies; seedling drought tolerance. The day-length is an important factor in regulating flowering as well as the phenotypic plasticity of seed germination which is also affected by maternal factors.

This volume focuses on the structure, function and regulation of plant signaling G proteins and their function in hormonal pathways, polarity, differentiation, morphogenesis and responses to biotic and abiotic stresses.

Plants are sessile organisms that need to continuously coordinate between external and internal cues. This coordination requires the existence of hubs to allow cross-talk between different signaling pathways. A single family of Rho GTPases, termed either ROPS or RACs, and heterotrimeric G proteins have emerged as the major molecular switches in a multitude of signal transduction pathway in plants.

It was around 1970, I had just completed a 5-year breeding project aiming at fxing fower colour in gerbera progenies: white, yellow, pink, and red; colour homogeneity was sound, but size and shape still required some improvement. The problem was defnitely resolved by Murashige and Skoog, USA who published a reliable protocol for gerbera micropro- gation. In short, my gerbera seed lines were immediately rendered obsolete by this e- cient cloning system, able to produce millions of plants of a matchless and previously unknown homogeneity, the uniformity of fower shape and colour being the basic requi- ments for the market. The success of micropropagation resulted in a tremendous growth in gerbera fower production worldwide, and this species conquered a leading place in the foriculture industry. This personal experience stresses the impact of micropropagation on the genetic improvement research strategies in ornamentals. Micropropagation has become "in- sive", especially in ornamental plant material issues. Today, hundreds of protocols exist; however, only a modest percentage of them are exploited economically. Thus, only micropropagation of plants with a high market price range, like orchids for instance, has proved cost-effective and achieved great success. Micropropagation is a labour-intensive system: hand-power is estimated to rep- sent 60-70% of total costs. This explains the outsourcing of the major labs in developing countries where labour is cheaper. Nevertheless, certain industrial protocols remain a proprietary technology of leading labs, mostly western, with the exception of Japan and Taiwan.

which individuals are heterozygous (H). A review by Selander (1976] comparing these param eters in various populations has been followed by many other studies. In the present volume, J. B. Mitton has used H to evaluate the importance of heterozygosity in natural populations. The degree of polymorphism expressed by P, has been used in several contributions to approach various problems of population genetics. particularly breeding structure and mating systems by Hamrick, Barrett and Shore, Brown, Burdon and Jarosz. as well as Soltis and Soltis, and Wyatt. Stoneburner. and Odrzykoski. New knowledge derived from these investigations has strengthened a point of view already stressed by Darwin: evolution takes place in a complex environment, that can be constantly changing over long periods of time. or can alternate between long periods of relative stability and cycles of rapid change. The most successful plant species become adjusted to these vagaries in several ways, including shifts in heterozygosity. polymorphism and mating systems. The strength of isozyme ana ysis for testing hypotheses is well illustrated by the contribution of the Soltises, who have shown clearly that a previously held hypothesis, predicting self fertilization fortified by polyploid genetic segregations in ferns, must be rejected."

Grassland farming in Europe was already established during the settlement of the rst farmers together with their domesticated animals after the last ice age. Since then, grassland provides the forage basis to feed ruminant animals for the p- duction of meat and milk. Depending on the ecological conditions and intensity of usage, various plant communities with different species developed, displaying a rich biodiversity. With the introduction of improved crop rotations at the end of the 16th century, grasses and legumes were also grown to an important extent as forage crops on arable land. In the last decades the importance of amenity grasses increased markedly, due to the demand of the society for new usages like landscape protection. Around 1900 interested farmers and academics identi ed the need for gra- land improvement through systematic selection and seed production. This marks the beginning of breeding and research in companies but also at universities and specialized research institutes. Plant collection started with many of the species that are still of importance today. The collected materials were grouped according to the intended use and some type of phenotypic selection was applied. Seed mul- plication of such populations was performed in pure stands and the harvested seed was marketed. Although the vegetative biomass and its quality are of utmost imp- tance in forage crop breeding, it is the seed yield potential which determines the commercial success of a new variety.

The symposium on "Zinc in Soils and Plants" is the third in a series which began with "Copper in Soils and Plants" in Perth in 1981 and continued with "Manganese in Soils and Plants" in Adelaide in 1988. The symP9sium brings together a series of valuable accounts of many aspects of the reactions of zinc in soils, the uptake, transport and utilization of zinc in plants, the diagnosis and correction of zinc deficiency in plants and the role of zinc in animal and human nutrition. I am grateful for the financial support provided by Grains Research and Development Corporation, Rural Industries Research and Development Corporation, Wool Research and Development Corporation, Ansett Australia, and Qantas Australian. I am most appreciative of the willingness of many scientists to act as referees: G S P Ritchie, R J Gilkes, N C Uren, K Tiller, BLeach, H Greenway, N E Longnecker, J F Loneragan, Z Rengel, C A Atkins, J W Gartrell, P J Randall, D G Edwards, R J Hannam, R J Moir, J E Dreosti, N Suttle, C L White, H Marschner, N Wilhelm, M McBride. All provided valuable comments on the manuscripts. Finally, I thank Mrs M Davison who provided excellent secretarial assistance. A.D. Robson September 1993 Chapter 1.

The inflorescence of the monoecious maize plant is unique among the Gramineae in the sharp separation of the male and female structures. The male tassel at the terminus of the plant most often sheds pollen before the visual appearance of the receptive silks of th the female ear at a lateral bud, normally at the 10 leaf [I]. Earlier studies examined the ontogeny of the growing tissues beginning with the embryo in the kernel through to the obvious protuberances of the growing point as the kernel germinates. The differentiated developing soon-to-become tassel and the lateral bulges that develop into the ears on the lateral buds become apparent very early in the germinating kernel [2, 3, 46]. A certain number of cells are destined for tassel and ear development [8]. As the plant develops, there is a phase transition [\3, 16] from the vegetative lateral buds to the reproductive lateral buds. This change in phase has been ascribed to genotypic control as evidenced in the differences among different genotypes in the initiation of the reproductive [I]. The genetic control of tassel and ear initiation has been gleaned from anatomical observations. Lejeune and Bernier [I2] found that maize plants terminate the initiation of additional axillary meristems at the time of tassel initiation. This would indicate that the top-most ear shoot is initiated on the same day as the initiation of tassel development and this event signals the end of the undifferentiated growing point.

Over recent years, progress in micropropagation has not been as rapid as many expected and, even now, relatively few crops are produced commercially. One reason for this is that the biology of material growing in vitro has been insufficiently understood for modifications to standard methods to be made based on sound physiological principles. However, during the past decade, tissue culture companies and others have invested considerable effort to reduce the empirical nature of the production process. The idea of the conference `Physiology, Growth and Development of Plants and Cells in Culture' (Lancaster, 1992) was to introduce specialists in different areas of plant physiology to micropropagators, with the express aims of disseminating as wide a range of information to as large a number of participants as possible, and beginning new discussions on the constraints and potentials affecting the development of in vitro plant production methods. This book is based on presentations from the conference and has been divided into two main sections, dealing with either aspects of the in vitro environment -- light, nutrients, water, gas -- or with applied aspects of the culture process -- morphogenesis, acclimation, rejuvenation, contamination.

Photobiology - the science of light and life - begins with basic principles and the physics of light and continues with general photobiological research methods, such as generation of light, measurement of light, and action spectroscopy. In an interdisciplinary way, it then treats how organisms tune their pigments and structures to the wavelength components of light, and how light is registered by organisms. Then follow various examples of photobiological phenomena: the design of the compound eye in relation to the properties of light, phototoxicity, photobiology of the human skin and of vitamin D, photomorphogenesis, photoperiodism, the setting of the biological clock by light, and bioluminescence. A final chapter is devoted to teaching experiments and demonstrations in photobiology.
This book encompasses topics from a diverse array of traditional disciplines: physics, biochemistry, medicine, zoology, botany, microbiology, etc., and makes different aspects of photobiology accessible to experts in all these areas as well as to the novice. It is intended primarily for graduate students and for researchers who wish to look outside their speciality, but can also act as a source of information for undergraduate students.

The Second International Congress on Photosynthesis Research took place in Stresa, Italy during June 24-29, 1971; two centuries after the discovery of Photosynthesis by Joseph Priestley in 1771. This important anniversary was celebrated at the Congress by a learned account of Priestley's life and fundamental discoveries given by Professor Robin HILL, F. R. S. Professor HILL's lecture opens the first of the three volumes which contains the contributions presented at the Congress. The manuscripts have been distributed into three volumes. Volume I con tains contributions in the areas of primary reactions and electron transport; Volume II ion transport and photophosphorylation, and Volume III carbon assimilation, regulatory phenomena, developmental aspects, and from the two special sessions of the Congress devoted to evolution and photorespiration. It is realized that this division is necessarily somewhat arbitrary since many contributions relate to more than one of the above mentioned titles. However, the large number of contributions (over 3000 typed pages) made it impossible to publish the proceedings in less than three volumes. The printing of these volumes and the organization of the Congress were made possible by a contribution from the Consigio Nazionale delle Ricerche of Italy. The generous support of the Istituto Lombardo Acca demia di Scienze e Lettere to the publication of these proceedings is gratefully acknowledged. The editors wish to express their appreciation to all the scientists who contributed the results of the investigations, for their coopera tion; and to Drs."

Plant cell and tissue culture is a relevant area of experimental biology that has been developed for some decades to become an indispensable tool of plant biotechnology. Progress in this area, sometimes tumultuous, has been regularly recorded by the proceedings of the congresses of the International Association for Plant Tissue Culture which have been held every four years in several continents. This book reports plenary lectures, keynote lectures and invited oral presentations given at the last congress held in Florence. It is a useful reference guide both for established scientists and students on both traditional and emerging fields of plant biology. The following topics are covered: In vitro Culture and Plant Regeneration; Plant Propagation; Haploids; Somatic Hybridisation; Reproductive Systems; Genetic Variability; Gene Transfer; Organelles; Biotechnology of Tropical and Subtropical Species; Agronomic Traits; Somatic Embryogenesis; Meristems; Cell Surface; Growth Regulators; Reception and Transduction of Signals; Gene Expression under Extreme Conditions; Primary Metabolism; Secondary Metabolism; Transport; Large Scale Production.

Achievements today in plant biotechnology have already surpassed all previous expectations. Plant biotechnology, integrated with classical breeding, is now on the verge of creating the evergreen revolution' to solve the world's envisaged tripled demand for food, agricultural commodities and natural products. New biotechnologies are being continuously adapted to agricultural practices, opening new vistas for plant utilization. Plant biotechnology is changing the plant scene in three major areas: (1) growth and development control (vegetative, generative and propagation), (2) protecting plants against the ever-increasing threats of abiotic and biotic stress, (3) expanding the horizons by producing specialty foods, biochemicals and pharmaceuticals. The potential for improving plant and animal productivity and their proper use in agriculture relies largely on newly-developed DNA biotechnology and molecular markers. These techniques enable the selection of successful genotypes, better isolation and cloning of favorable traits, and the creating of transgenic organisms of importance to agriculture. These areas were extensively discussed at the 9th international congress of the International Association of Plant Tissue Culture and Biotechnology, Plant Biotechnology and In Vitro Biology in the 21st Century', which was held in Jerusalem in June 1998. The present book of proceedings contains the variety of scientific achievements and techniques that were presented: Basic and Applied Aspects of Growth, Development and Differentiation; Genetic Manipulations: Transformation and Gene Expression, Hybridization, Haploidization and Mutagenesis; Genetic Stability and Instability, Selection and Variability; Regulation of Primary and Secondary Metabolism; Model Systems: Cell Cycle, Transport and Signal Transduction; Biotechnology for Plant Protection: Abiotic and Biotic Stress; Biotechnology for Crop Improvement: Yield, Quality and Production of Valuable Substances; Novel Micropropagation Methods; New Markets and Commercial Applications; Intellectual Property Rights.

Dr Samuel Johnson, that famous eighteenth century lexicographer, said of oats 'A grain which in England is generally given to horses but in Scotland supports the people'. And presumably it was a Scotsman who riposted 'But what people and what horses ' That exchange encapsulates much of the history and role of oats - a cereal, once important as human food in parts of northern Europe but latterly used mainly as animal feed, especially favoured for horses. Although no longer a major food anywhere, oats still have a special and favoured niche in the cuisine of people living in the cooler and wetter regions of some parts of northern Europe. However, there is currently a resurgence of interest in the crop, because there is now considerable scientific evidence to support the view of Scotsmen who never doubted its dietary value. This book - very much an international effort, carefully orchestrated by Robert Welch - traces the origin, history and scientific progress which forms a sound basis for any further crop improvement and for broadening the utilization and marketing of oat products. Should rational consider ations lead to an increase in the importance of this cereal, I, for one, would be glad since I believe the rural landscape is the poorer for the increased rarity of golden fields of rippling oats which I used to be involved in harvesting."

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.

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.

JACQUES S. BECKMANN & THOMAS C. OSBORN Extraordinary progress has been made in the analyses of the genetic structures of higher eukaryotic genomes. Only ten years elapsed between the initial proposals to use molecular DNA markers for the generation of a complete linkage map of the human genome [5, 17] and the first description of a 10 centimorgan map of one of its chromosomes [22], soon to be followed by others. The availability of molecular DNA markers, henceforth called genomic markers [for a review of their properties see 1, 2, 20], represents a milestone in genetics by providing the capacity for complete genetic coverage of all genomes. It is important to remember that the nature of the DNA polymorphism or of the specific method used to uncover it can be quite different for different marker loci. The genetic variation detected can be a result of a simple point mutation, a DNA insertion/deletion event, or a change in repeat copy number at some hypervariable DNA [11] or micro satellite [21] motif. Currently, the methods of detection can involve use of restriction endonucleases, nucleic acid hybridization, or DNA sequence amplification. Each of these sources of var iation and methods of detection can have utility for different applications. Furthermore, new approaches for the detection of DNA polymorphism are constantly emerging. The primary concern here is that the monitored poly morphism defines a genetic marker 'useful' for the desired application.

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 highly structured eucaryotic cell with its complex division of biochemical labour requires a distinct protein complement in each cellular structure and compartment. Nuclear coded and cytosolically synthesized polypeptides are specifically sorted to every corner of the cell in a post- or co-translational manner. The presence of separate genomes and protein translation machineries in plastids and mitochondria requires further coordination not only on the transcriptional, translational but also most likely on the protein import level. Numerous different protein transport systems have developed and coexist within plant cells to ensure the specific and selective composition of every sub-cellular compartment. This volume summarizes the current knowledge on protein trafficking in plant cells. Aside from the fundamental aspects in cell biology of how specific pre-protein sorting and translocation across biological membranes is achieved, a major focus is on transport, modification and deposition of plant storage proteins. The increasing use of plants as bioreactors to provide custom-designed proteins of different usage requires detailed understanding of these events. This text is directed not only at students and professionals in plant cell and molecular biology but also at those involved in horticulture and plant breeding. It is intended to serve as a text and guide for graduate-level courses on plant cell biology and as a valuable supplement to courses in plant physiology and development. Scientists in other disciplines who wish to learn more about protein translocation in plants will also find this text an up-to-date source of information and reference.

The technique of chlorophyll fluorescence has a relatively short history, beginning with the observations by Kautsky (Kautsky and Hirsch, 1931). Since that time there have been several* reviews devoted to the subject, with most of them highly theoretical (Bohlar-Nordenkampf and Oquist, 1993; Dau, 1994; Schreiber et aI. , 1994). There have also been many books devoted to generalized spectrophotometric and microscopic fluorescence techniques. However, to the best of our knowledge there has not been a book completely devoted to the practical applications and uses of chlorophyll fluorescence in plant biology. As techniques mature, applications multiply and so do their potential advantages. The chlorophyll fluorescence technique is maturing as can be seen in the increasing numbers of publications that are devoted to its use. Therefore, we considered that now was a good time to compile the existing knowledge for the applied use of this technique and provide a single volume to which a novice or experienced user could refer. Highly trained experts in the field of photobiology have primarily used the chlorophyll fluorescence technique in the past. In that work, understanding the mechanisms and controls of the photosynthetic processes was the main focus of activity and discussion. Much of the equipment used was highly specialized and expensive, or in some cases one-of-a-kind lab designed units. However, the development of several reliable commercially available chlorophyll fluorescence monitoring instruments has changed the potential user base for the technique.

Tropical climates, which occur between 23 Degrees30'N and S latitude (Jacob 1988), encompass a wide variety of plant communities (Hartshorn 1983, 1988), many of which are diverse in their woody floras. Within this geographic region, temperature and the amount and seasonality of rainfall define habitat types (UNESCO 1978). The F AO has estimated that there 1 are about 19 million km of potentially forested area in the global tropics, of which 58% were estimated to still be in closed forest in the mid-1970s (Sommers 1976; UNESCO 1978). Of this potentially forested region, 42% is categorized as dry forest lifezone, 33% is tropical moist forest, and 25% is wet or rain forest (Lugo 1988). The species diversity of these tropical habitats is very high. Raven (1976, in Mooney 1988) estimated that 65% of the 250,000 or more plant species of the earth are found in tropical regions. Of this floristic assemblage, a large fraction are woody species. In the well-collected tropical moist forest of Barro Colorado Island, Panama, 39. 7% (481 of 1212 species) of the native phanerogams are woody, arborescent species (Croat 1978). Another 21. 9% are woody vines and lianas. Southeast Asian Dipterocarp forests may contain 120-200 species of trees per hectare (Whitmore 1984), and recent surveys in upper Amazonia re corded from 89 to 283 woody species ~ 10 cm dbh per hectare (Gentry 1988). Tropical communities thus represent a global woody flora of significant scope.