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This study was designed to test the hypothesis that individuals with antisocial, particularly violent, histories of offending behavior have specific problems in social cognition, notably in relation to accurately envisioning mental states. Eighty-three male offenders on community license, 65% of whom met the threshold for antisocial personality disorder (ASPD), completed a battery of computerized mentalizing tests requiring perspective taking (Perspectives Taking Test), mental state recognition from facial expression (Reading the Mind in the Eyes Test), and identification of mental states in the context of social interaction (Movie for the Assessment of Social Cognition). The results were compared with a partially matched sample of 42 nonoffending controls. The offender group showed impaired mentalizing on all of the tasks when compared with the control group for this study when controlling for demographic and clinical variables, and the offending group performed poorly in comparisons with participants in published studies, suggesting that limited capacity to mentalize may be part of the picture presented by individuals with histories of offending behavior. Offenders with ASPD demonstrated greater difficulty with mentalizing than non-ASPD offenders. Mentalization subscales were able to predict offender status and those with ASPD, indicating that specific impairments in perspective taking, social cognition, and social sensitivity, as well as tendencies toward hypomentalizing and nonmentalizing, are more marked in individuals who meet criteria for a diagnosis of ASPD. Awareness of these deficits may be helpful to professionals working with offenders, and specifically addressing these deficits may be a productive aspect of therapy for this "hard to reach" clinical group.

Mindfulness has been used as an intervention for specific sexual dysfunctions in women; evidence has also accumulated for the role of mindfulness in treating the kinds of psychological difficulties which are associated with sexual dysfunction. This paper describes, within a clinical context, a qualitative approach to protocol and theory development for a mindfulness-based sex and intimate relationship (MSIR) programme as a generic adjunct to sex therapy. The aim was to adapt the mindfulness-based cognitive therapy (MBCT) group protocol to address diverse sexual and intimacy difficulties. The protocol was developed on an iterative basis and piloted with 30 patients referred from a sexual dysfunction clinic. Twelve participants came forward to be interviewed and their transcripts were analysed in two phases using a grounded theory approach, to produce a model generating testable hypotheses. The reduction of experiential and behavioural avoidance was central to the model that emerged from the analysis, along with the relinquishing of sexual goals in favour of focus on sensory experience. The analysis led also to a tentative staging of mindfulness, associated with enhanced experience. The adapted MBCT protocol for diverse sexual difficulties was found to be feasible and appeared positive for participants. Thus, MSIR shows promise as a generic adjunct to sex therapy.

We have used high-sensitivity capillary electrophoresis coupled to a laser-induced fluorescence detection method to quantify 16 amino acids in wheat (Triticum aestivum) sieve tube (ST) samples as small as 2 nL collected by severing the stylets of feeding aphids. The sensitivity of the method was sufficient to determine a quantitative amino acid profile of individual STs without the need to bulk samples to produce larger volumes for analysis. This allowed the observation of the full range of variation that exists in individual STs. Some of the total concentrations of amino acids recorded are higher than those reported previously. The results obtained show variation in the concentrations of phenylalanine (Phe), histidine/valine (His/Val), leucine/isoleucine (Leu/Ile), arginine, asparagine, glutamine, tyrosine (Tyr), and lysine (Lys) across the ST samples. These could not be explained by plant-to-plant variation. Statistical analyses revealed five analytes (Tyr, Lys, Phe, His/Val, and Leu/Ile) that showed striking covariation in their concentrations across ST samples. A regression analysis revealed a significant relationship between the concentrations of Tyr, Lys, Phe, Leu/Ile, His/Val, asparagine, arginine, and proline and the time of collection of ST samples, with these amino acids increasing in concentration during the afternoon. This increase was confirmed to occur in individual STs by analyzing samples obtained from stylet bundles exuding for many hours. Finally, an apparent relationship between the exudation rate of ST sap and its total amino acid concentration was observed: samples containing higher total amino acid concentrations were observed to exude from the severed stylet bundles more slowly.

Supplemental Digital Content is Available in the Text., Objective: Men who have sex with men (MSM) are the key population most affected by HIV in Europe. We performed the first European multicenter, simple-randomized parallel-group study to test the effectiveness of a theory-guided computer-assisted intervention to improve safer sex among HIV-positive men who have sex with men. Methods: Between February, 2011 and February, 2013, 112 participants were enrolled in 8 different European HIV-care settings. Intervention participants received 3 individual counseling sessions facilitated by trained service providers using computer-assisted tools. The control-group received sexual health advice delivered as part of regular HIV care. Outcome behavior (self-reported condom use at last intercourse; combined HIV transmission risk score), its influencing factors, and mediating variables were assessed at baseline, and at 3 and 6 months follow-up. Mixed effects models were used to compare primary outcomes (condom use at last intercourse, HIV transmission risk score), and mediation analysis to explore intervention effects. Results: Condom use at last intercourse increased more among intervention than control participants at 3 months follow-up (odds ratio of 3.83; P = 0.03), but not significantly at 6 months follow-up. Intervention participants reported a lower transmission risk at 3 months follow-up than controls (odds ratio compared with baseline of 11.53 and 1.28, respectively; P = 0.008), but this effect became nonsignificant at 6 months. Intervention effects were mediated by the proximal variables, self-efficacy to negotiate condom use and condom attitudes. Conclusions: This intervention showed short-term effectiveness. The intervention should be replicated in other settings, eventually investigating if booster-counseling sessions would yield a longer lasting effect.

One of the challenges of comparative genomics is to identify specific genetic changes associated with the evolution of a novel adaptation or trait. We need to be able to disassociate the genes involved with a particular character from all the other genetic changes that take place as lineages diverge. Here we show that by comparing the transcriptional profile of segregating families with that of parent species differing in a novel trait, it is possible to narrow down substantially the list of potential target genes. In addition, by assuming synteny with a related model organism for which the complete genome sequence is available, it is possible to use the cosegregation of markers differing in transcription level to identify regions of the genome which probably contain quantitative trait loci (QTLs) for the character. This novel combination of genomics and classical genetics provides a very powerful tool to identify candidate genes. We use this methodology to investigate zinc hyperaccumulation in Arabidopsis halleri, the sister species to the model plant, Arabidopsis thaliana. We compare the transcriptional profile of A. halleri with that of its sister nonaccumulator species, Arabidopsis petraea, and between accumulator and nonaccumulator F3s derived from the cross between the two species. We identify eight genes which consistently show greater expression in accumulator phenotypes in both roots and shoots, including two metal transporter genes (NRAMP3 and ZIP6), and cytoplasmic aconitase, a gene involved in iron homeostasis in mammals. We also show that there appear to be two QTLs for zinc accumulation, on chromosomes 3 and 7.

A monospecific antiserum to a Cucurbita ascorbate oxidase was shown to cross-react with the mustard enzyme. Purified antiserum was used in rocket immunoelectrophoresis plates to measure the amount of ascorbate oxidase protein in mustard cotyledon and hypocotyl extracts. On transfer from darkness to far-red light and activity of the enzyme in expanding cotyledons increased but the amount of enzyme protein remained the same. Unimbibed mustard seeds were shown to contain the same amount of antigenic protein as expanding cotyledons although in the seeds the enzyme was inactive. In hypocotyls continuous far-red light treatment also led to an increase in ascorbate oxidase activity; in this case there was also an increase in enzyme protein although this was relatively small. The results are discussed in relation to the mechanism by which phytochrome may control the activity of this enzyme.

Many biologically and economically important traits in plants and animals are quantitative/multifactorial, being controlled by several quantitative trait loci (QTL). QTL are difficult to locate accurately by conventional methods using molecular markers in segregating populations, particularly for traits of low heritability or for QTL with small effects. In order to resolve this, large (often unrealistically large) populations are required. In this paper we present an alternative approach using a specially developed resource of lines that facilitate QTL location first to a particular chromosome, then to successively smaller regions within a chromosome (< or = 0.5 cM) by means of simple comparisons among a few lines. This resource consists of "Stepped Aligned Inbred Recombinant Strains" (STAIRS) plus single whole Chromosome Substitution Strains (CSSs). We explain the analytical power of STAIRS and illustrate their construction and use with Arabidopsis thaliana, although the principles could be applied to many organisms. We were able to locate flowering QTL at the top of chromosome 3 known to contain several potential candidate genes.

Unmodified samples of barley (Hordeum vulgare) sieve tube sap have been obtained by severing the stylets (stylectomy) of feeding aphids and collecting the exuding liquid. Primers were designed to direct the amplification of a series of specific cDNAs encoding barley proteins selected because of their significance in sieve tube function. mRNA encoding the H(+)/sucrose co-transporter SUT1, a putative aquaporin and the H(+)/ATPase PPA1 were detected in sieve tube sap. These mRNA species appear to be present at very low concentrations. mRNA encoding the potassium transporter HAK1 could not be detected. The results strongly suggest that some mRNA species are imported into sieve elements, which are enucleate, from neighbouring companion cells.

One hundred and twenty-two AFLP markers were mapped using an IR64 x Azucena rice doubled-haploid (DH) population. The distribution of these mapped markers was monitored across a set of 48 diverse landraces of rice. Strong statistical associations were observed between 960 of the 7381 possible pairs of markers across the diverse material. These 960 strongly associated pairs of markers mapped to the same chromosomes in only 111 cases. The remaining 849 pairs were the result of association between markers found on different chromosomes. More than 21% of these genetically unlinked but strongly associated markers are not randomly distributed across the genome but instead occupy blocks of DNA on different rice chromosomes. Amongst associated blocks, there has clearly been maintenance of combinations of marker alleles across very diverse germplasm. Analyses have also revealed that markers are found in association with performance for each of four quantitative traits in both the diverse landrace material and a DH mapping population. It is proposed that the present data provide strong evidence for the co-adaptation of geographically distinct landraces and that this has resulted over time in the maintenance of 'adaptive gene complexes' involving agronomically important quantitative traits.

2009 is a special year as it is the 200th anniversary of the birth of Charles Darwin and 150 years since the first publication of On the Origin of Species, which rocked science and society. This article is written as a ‘Letter to Darwin’ and attempts to define and discuss some of the biological discoveries in which he would surely have had a great interest. In fact, because of the difficulties associated with explaining the processes, structures, terminologies and technologies, this is the second letter written to Darwin by the author. Readers interested in a longer initial letter that reviews relevant material up to 1960 are referred to www.biochemistry.org/education.

AFLP marker data were generated for a doubled haploid rice mapping population developed from a cross between IR64 (indica) and Azucena (japonica) varieties, as well as for a diverse set of rice germplasm. A total of 151 AFLP markers were incorporated into an existing restriction fragment length polymorphism framework map and compared with a published map. Markers associated with the indica–japonica subspecific differentiation in Asian rice were also mapped and were found to be distributed throughout the genome. Sources of mapping errors were examined and the possibility of such errors being caused by co-migration of bands and segregation distortion was explored. In the case of markers that show distorted segregation, it was concluded that one-third of these may be affected by gametophytic/sterility genes and a futher one-third may arise because of association with the indica–japonica differentiation.

An understanding of the genetic structure of populations is vital for the formation of optimum collection, conservation and utilization strategies for plant genetic resources. This is of particular importance in the case of in-situ conservation, a strategy gaining in popularity. The population genetic structures of five wild lentil taxa, Lens culinaris subsp. orientalis, L. odemensis, L. ervoides, L. nigricans and L. lamottei were investigated using isozyme electrophoresis and random amplified polymorphic DNA (RAPD). Approximately 20 plants from each of 5 populations per taxon were screened for variation at 11 isozyme loci and using three RAPD primers. Levels of variation were generally low, although considerable variation existed in the levels of diversity found within populations of L. culinaris subsp. orientalis and L. lamottei. Comparison of the results obtained in this study with the results obtained in a previous study indicate that this is a trend occurring across all species. It implies that levels of diversity within populations must be measured and considered prior to targeting of specific populations for in-situ conservation. Analysis of molecular variance of both isozyme and RAPD data revealed that between 78% and 99% of the variation was attributable to between-population differences. Isozyme results from L. lamottei populations were, however, contradictory. Possible explanations for this difference are discussed.

Sequence variation in the ITS1 locus of the nuclear ribosomal DNA in beets has previously been used to reconstruct phylogeny of the species in the genus Beta. We have developed protocols that allow the identification of Beta taxa by use of taxon-specific primers. Beta sections, species and subspecies can be identified. Differences within the ITS1 region of a single base can be exploited for species identification. The results from this study not only provide effective methods for wild beet identification, but also indicate the potential use of the techniques in other crops.

Genetic variation between samples of Oryza sativafrom 19 localities in Bangladesh and Bhutan was assessed using two PCR-based molecular marker systems: RAPD (random amplification of polymorphic DNA) and ISSR-PCR (inter-simple sequence repeat polymerase chain reaction). Employing RAPD, a set of 14 decanucleotides of arbitrary sequence directed the amplification of 94 reproducible marker bands, 47 (50%) of which were polymorphic. In addition, a set of 9 ISSR primers were used to direct amplification of 71 PCR products, 40 (56%) of which were polymorphic. Multivariate analyses of the two PCR-based molecular marker data sets provided evidence that the patterns of variation correspond with the classification described by Glaszmann [9] using isozyme analysis. Subtle differences in the relationships revealed between rice groups using the two types of PCR-based marker led to investigations of their map positions using an intraspecific doubled haploid mapping population. The observation that the chromosomal locations of markers can influence diversity assessments is presented and the significance of this is discussed.

List of Contributors. Preface. List of Acronyms. 1 Introduction (The Editors). References. 2 Channel Characterization (P. Amirshahi, F. Canete, K. Dostert, S. Galli, M. Katayama and M. Kavehrad). 2.1 Introduction. 2.2 Channel Modeling Fundamentals. 2.3 Models for Outdoor Channels: LV Case. 2.4 Models for Outdoor Channels: MV Case. 2.5 Models for Indoor Channels. 2.6 Noise and Disturbances. 2.7 MeasuringTechniques. 2.8 PLC Channel EmulationTools. 2.9 Reference Channels for Access Domain. 3 Electromagnetic Compatibility (H. Hirsch and M. Koch). 3.1 Introduction. 3.2 Parameters for EMC Considerations. 3.3 Electromagnetic Emission. 3.4 Electromagnetic Susceptibility. 3.5 EMC Coordination. 3.6 EMC Regulationin Europe. 3.7 Final Remarks. 4 Coupling (P. A. Janse van Rensburg). 4.1 Introduction. 4.2 Filtering Basics. 4.3 Transformer-Capacitor Coupler Design. 4.4 Impedance Adaptation Concepts. 4.5 Experimental Verification. 4.6 Further Possibilities. 5 Digital Transmission Techniques (M. Ardakani, G. Colavolpe, K. Dostert, H. C. Ferreira, D. Fertonani, T. G. Swart, A. M. Tonello, D. Umehara and A. J. H. Vinck). 5.1 Introduction. 5.2 Modulation and Coding for Narrowband PLC Systems. 5.3 Modulation and Coding for Broadband PLC Systems. 5.4 Conclusion. 6 Protocols for PLC Systems (G. Bumiller, H. Hrasnica, L. Lampe, M. Lobashov and T. Stockhammer). 6.1 Introduction. 6.2 Broadband PLC Media Access Control Layer. 6.3 Protocols for PLC Supporting Energy Management Systems. 6.4 Internet Protocol Television Over PLC. 7 Industrial and International Standards on PLC-based Networking Technologies (Galli, M. Koch, H. A. Latchman, S. Lee and V. Oksman). 7.1 Introduction. 7.2 PLC Standardization by Industrial Alliances. 7.3 International Standards on PLC-Networking Technology. 7.4 ETSI and CENELEC Standards. 7.5 International EMC Product Standardization. 8 Systems and Implementations (I. Berganza Valmala, G. Bumiller, H. A. Latchman, M. V. Ribeiro, A. Sendin Escalona, E. R. Wade and L. W. Yonge). 8.1 Introduction. 8.2 PLC Smart Grid Systems. 8.3 PLC Broadband Access Systems. 8.4 Multimedia PLC Systems. 8.5 DC-PLC Systems. 8.6 PLC in Emerging Countries. 9 Conclusions (The Editors). Index.

A sensitive CE with LIF method has been developed for quantitative analysis of small carbohydrates. In this work, 17 carbohydrates including mono-, di- and oligosaccharides\ud were simultaneously derivatized with 4-fluoro 7-nitrobenzo furazane (NBD-F) via a twostep reaction involving reductive amination with ammonia followed by condensation with NBD-F. Under the optimized derivatization conditions all carbo-hydrates were successfully derivatized within 2.5 h and separated within 15 min using borate buffer (90 mmol/L, pH 9.2). For sugar standards LODs were in the range of 49.7 to\ud 243.6 nmol/L. Migration time and peak area reproducibility were better than RSD 0.1 and 3%, respectively. The method was applied to measure sugars in nanoliter volume samples of phloem sap obtained by stylectomy from wheat and to honeydew samples obtained from aphids feeding from wheat and willow.

Different approaches are described for the characterisation of the low voltage mains network that is used for high-speed data transmission broadband over power line (BPL). Part 1 investigated the disturbance scenario of these BPL devices and importance will be given to develop a new measurement procedure in Comite Internationale Special des Perturbations Radioelectrotechnique (CISPR) to estimate the high-frequency characteristics of AC mains networks. The improvements of the measurement method that can also be applied to other wire-based telecommunication systems will also be presented. Part 2 shows the definitions and comparisons of different symmetry factors. The transfer of the results on the compliance test for BPL devices will also be depicted.

Different approaches for the characterisation of relevant parameters of the low-voltage mains network, used for high-speed data transmission (BPL, broadband over power line) are described. Part 1 of the paper depicts the disturbance scenario of these BPL devices and the motivation will be given for the development of a new measurement procedure in CISPR for the estimation of the high-frequency characteristics of AC mains network. The improvements of the measurement method is not restricted to BPL applications, but can also be applied to other wire-based telecommunication systems. Part 2 of the paper shows the definitions and comparisons of different symmetry factors. The transfer of the results on the compliance test for BPL devices will be shown.

• The mechanisms of metal hyperaccumulation are still not understood, so we conducted a quantitative trait locus (QTL) analysis of zinc (Zn) hyperaccumulation in Arabidopsis halleri, in a cross between this and its sister species, A. petraea, in order to determine the number and approximate location of the genomic regions significantly contributing to this adaptation. • An F2 cross between the two species was made, and the leaf Zn concentration of 92 individuals was measured at both low (10 μM) and high (100 μM) Zn concentrations. Twenty-five markers were established that were distributed on all of the eight chromosomes. • Mapping of the markers established that they were essentially collinear with previous studies. QTLs exceeding a logarithm to the base 10 of the odds (LOD) value of 3 were found on chromosomes 4 (low Zn), 6 (high Zn) and 7 both high and low Zn). Evidence for a QTL on chromosome 3 (low Zn) was also found. • This analysis validates a previously used method of QTL analysis, based on microarray analysis of segregating families. Genes that have altered during the evolution of this character should also be QTL: this analysis calls into question a number of candidate genes from consideration as such primary genes because they do not appear to be associated with QTLs.

Summary A commonly encountered difficulty with the genetic engineering of crop plants is that different varieties of a particular species can show great variability in the efficiency with which they can be transformed. This increases the effort required to introduce transgenes into particular genetic backgrounds. The use of Substitution Lines has allowed the finer mapping of three Quantitative Trait Loci (tf1, tf2 and tf3) that explain 26% of the variation in the efficiency of Agrobacterium-mediated transformation in Brassica oleracea. Use of an ‘orthogonal set’ of genotypes (containing all eight possible combinations of ‘positive’ and ‘negative’ alleles at the three QTL), along with time course studies of transgene expression, has allowed the determination of the stages at which these genes have their effects during transformation. With regard to control of the level of transient transgene expression, tf1 (on LGO1) alone has no detectable effect, whilst tf2 (on LGO3) and tf3 (on LGO7) have highly significant effects (P

One of the challenges of comparative genomics is to identify specific genetic changes associated with the evolution of a novel adaptation or trait. We need to be able to disassociate the genes involved with a particular character from all the other genetic changes that take place as lineages diverge. Here we show that by comparing the transcriptional profile of segregating families with that of parent species differing in a novel trait, it is possible to narrow down substantially the list of potential target genes. In addition, by assuming synteny with a related model organism for which the complete genome sequence is available, it is possible to use the cosegregation of markers differing in transcription level to identify regions of the genome which probably contain quantitative trait loci (QTLs) for the character. This novel combination of genomics and classical genetics provides a very powerful tool to identify candidate genes. We use this methodology to investigate zinc hyperaccumulation in Arabidopsis halleri, the sister species to the model plant, Arabidopsis thaliana. We compare the transcriptional profile of A. halleri with that of its sister nonaccumulator species, Arabidopsis petraea, and between accumulator and nonaccumulator F(3)s derived from the cross between the two species. We identify eight genes which consistently show greater expression in accumulator phenotypes in both roots and shoots, including two metal transporter genes (NRAMP3 and ZIP6), and cytoplasmic aconitase, a gene involved in iron homeostasis in mammals. We also show that there appear to be two QTLs for zinc accumulation, on chromosomes 3 and 7.

Publisher Summary The growing root tip is at the end of the translocation pathway and is highly dependent on the import of solutes for its continued growth and other metabolism. The delivery of organic solutes into growing root cells has been considered to occur by two completely different mechanisms: uptake from the apoplast across membranes or symplastic delivery through plasmodesmatally connected domains. The pathways have very different hardware and fundamentally different driving forces. Apoplastic uptake of solutes requires membrane transporters or channels, whereas in symplastically connected cells solutes and water can enter together without crossing a membrane. This chapter studies the relationship between root extension and solute deposition, reviews the evidence for the existence of symplastic and apoplastic pathways within the growing zone, and assesses the consequences of these two pathways for solute transport to growing sinks. Because qualitative changes in the pathway for solute delivery within the root-growing zone predict associated differences in the presence of specific transporters for both solutes and water, some speculations are offered as to the location of specific transporters within the root tip. To help link studies of solute delivery and growth in roots with studies on other tissues, parallels are drawn between the transport processes occurring in source, sink, and pathway.

Many biologically and economically important traits in plants and animals are quantitative/multifactorial, being controlled by several quantitative trait loci (QTL). QTL are difficult to locate accurately by conventional methods using molecular markers in segregating populations, particularly for traits of low heritability or for QTL with small effects. In order to resolve this, large (often unrealistically large) populations are required. In this paper we present an alternative approach using a specially developed resource of lines that facilitate QTL location first to a particular chromosome, then to successively smaller regions within a chromosome (or = 0.5 cM) by means of simple comparisons among a few lines. This resource consists of "Stepped Aligned Inbred Recombinant Strains" (STAIRS) plus single whole Chromosome Substitution Strains (CSSs). We explain the analytical power of STAIRS and illustrate their construction and use with Arabidopsis thaliana, although the principles could be applied to many organisms. We were able to locate flowering QTL at the top of chromosome 3 known to contain several potential candidate genes.

A broadly applicable method for the successful induction of root systems in a number of cultivars of A. majus has been determined. This involves a double filter-paper bridge with a liquid medium for root induction and allows the transfer of culture-grown plantlets to a glasshouse environment with minimal disturbance to the plant as a whole. 100% survival of transferred plantlets has been achieved with the inclusion of a few simple precautions upon shoot transfer and during the initial stages of plant establishment in vivo.

Using the technique of random amplified polymorphic DNA (RAPD), we have identified 116 amplification products in Musa germplasm using nine primers. This has enabled us to identify RAPD markers that are specific to each of nine genotypes of Musa representing AA, AAA, AAB, ABB, and BB genomes. The pattern of variation observed following the application of multivariate analyses to the RAPDs banding data is very similar to the pattern of variation defined using morphological characters and used to assign Musa material into the different genome classes.Key words: RAPD, Musa, genome, banana, plantain, genetic variation.

Using conventional methods it is impossible to extract RNA as uncomplexed intact molecules from the leaves of grapevines (Vitis vinifera L.) and from a number of woody perennial species that contain high levels of reactive phenolic compounds. A procedure involving the use of high concentrations of the chaotropic agent sodium perchlorate prevents the binding of phenolic compounds to RNA during extraction. Analyses of the phenolics present in plant tissues used in these experiments indicate that there is a poor correlation between the total phenolic content and the complexing of RNA. However, qualitative analyses suggest that proanthocyanidins are involved in the tanning of RNA during conventional extractions.

The aim of this study is to understand the parameters\ud regulating calcium ion distribution in leaves. Accumulation\ud of ions in leaf tissue is in part dependent on\ud import from the xylem. This import via the transpiration\ud stream is more important for ions such as calcium\ud that are xylem but not phloem mobile and cannot\ud therefore be retranslocated. Accumulation of calcium\ud was measured on bulk coriander leaf tissue (Coriandrum\ud sativum L. cv. Lemon) using ion chromatography\ud and calcium uptake was visualized using phosphorimages\ud of 45Ca2+. Leaves of plants grown in hydroponics\ud had elevated calcium in the centre of the leaf\ud compared with the leaf margin, while K+ was distributed\ud homogeneously over the leaf. This calcium was\ud shown to be localised to the mesophyll vacuoles using\ud EDAX. Stomatal density and evapotranspiration (water\ud loss per unit area of leaf) were equal at inner and outer\ud sections of the leaf. Unequal ion distribution but\ud uniformity of water loss suggested that there was\ud a difference in the extent of uncoupling of calcium and\ud water transport between the inner and outer leaf. Since\ud isolated tissue from the inner and outer leaf were able\ud to accumulate similar amounts of calcium, it is proposed\ud that the spatial variation of leaf calcium concentration\ud is due to differential ion delivery to the two\ud regions rather than tissue/cell-specific differences in\ud ion uptake capacity. There was a positive correlation\ud between whole leaf calcium concentration and the\ud difference in calcium concentration between inner and\ud outer leaf tissue. Exposing the plants to increased\ud humidity reduced transpiration and calcium delivery to\ud the leaf and abolished this spatial variation of calcium\ud concentration. Mechanisms of calcium delivery to\ud leaves are discussed. An understanding of calcium\ud delivery and distribution within coriander will inform\ud strategies to reduce the incidence of calcium-related\ud syndromes such as tip-burn and provides a robust\ud model for the transport of ions and other substances\ud in the leaf xylem.