RESUMEN
BACKGROUND AND AIMS: Plant water status is important for fruit development, because many fleshy fruits contain large amounts of water. However, there is no information on vascular flows of Persea americana 'Hass' avocado. The aims of this research were to explore the impact of drought stress on the water relationships of the 'Hass' avocado plant and its fruit growth. METHODS: Well-watered and water-stressed 'Hass' avocado plants were compared. Over 4 weeks, water flows through the shoot and fruit pedicel were monitored using external sap flow gauges. Fruit diameter was monitored using linear transducers, and stomatal conductance (gs), photosynthesis (A) and leaf and stem water potentials (Ñ°leaf and Ñ°stem) were measured to assess the response of the plants to water supply. KEY RESULTS: In well-watered conditions, the average water inflow to the shoot was 72 g day-1. Fruit water inflow was 2.72 g day-1, but there was water loss of 0.37 g day-1 caused by the outflow (loss back into the tree) through the vascular tissues and 1.06 g day-1 from the fruit skin. Overall, fruit volume increased by 1.4 cm3 day-1. In contrast, water flow into fruit of water-stressed plants decreased to 1.88 g day-1, with the outflow increasing to 0.61 g day-1. As a result, increases in fruit volume were reduced to 0.4 cm3 day-1. The values of A, gs and sap flow to shoots were also reduced during drought conditions. Changes in the hourly time-courses of pedicel sap flow, fruit volume and stem water potential during drought suggest that the stomatal response prevented larger increases in outflow from the fruit. Following re-watering, a substantial recovery in growth rate was observed. CONCLUSIONS: In summary, a reduction in growth of avocado fruit was observed with induced water deficit, but the isohydric stomatal behaviour of the leaves helped to minimize negative changes in water balance. Also, there was substantial recovery after re-watering, hence the short-term water stress did not decrease avocado fruit size. Negative impacts might appear if the drought treatment were prolonged.
Asunto(s)
Sequías , Frutas , Persea , Fotosíntesis , Estomas de Plantas , Agua , Persea/fisiología , Persea/crecimiento & desarrollo , Estomas de Plantas/fisiología , Frutas/fisiología , Frutas/crecimiento & desarrollo , Agua/fisiología , Agua/metabolismo , Fotosíntesis/fisiología , Hojas de la Planta/fisiología , Hojas de la Planta/crecimiento & desarrollo , Transpiración de Plantas/fisiología , Tallos de la Planta/fisiología , Tallos de la Planta/crecimiento & desarrollo , Tallos de la Planta/anatomía & histología , Brotes de la Planta/fisiología , Brotes de la Planta/crecimiento & desarrollo , Estrés Fisiológico/fisiología , DeshidrataciónRESUMEN
BACKGROUND: Preventing suicide and self-harm is a global health priority. Although there is a growing evidence base for the effectiveness of psychoanalytic and psychodynamic psychotherapies for a range of disorders, to date there has been no systematic review of its effectiveness in reducing suicidal and self-harming behaviours.AimsTo systematically review randomised controlled trials of psychoanalytic and psychodynamic psychotherapies for suicidal attempts and self-harm. METHOD: We searched PubMed, PsycINFO, Psycharticles, CINAHL, EMBASE and the Cochrane Central Register of Controlled Trials for randomise controlled trials of psychoanalytic and psychodynamic psychotherapies for reducing suicide attempts and self-harm. RESULTS: Twelve trials (17 articles) were included in the meta-analyses. Psychoanalytic and psychodynamic therapies were effective in reducing the number of patients attempting suicide (pooled odds ratio, 0.469; 95% CI 0.274-0.804). We found some evidence for significantly reduced repetition of self-harm at 6-month but not 12-month follow-up. Significant treatment effects were also found for improvements in psychosocial functioning and reduction in number of hospital admissions. CONCLUSIONS: Psychoanalytic and psychodynamic psychotherapies are indicated to be effective in reducing suicidal behaviour and to have short-term effectiveness in reducing self-harm. They can also be beneficial in improving psychosocial well-being. However, the small number of trials and moderate quality of the evidence means further high-quality trials are needed to confirm our findings and to identity which specific components of the psychotherapies are effective.Declaration of interestNone.
Asunto(s)
Terapia Psicoanalítica/métodos , Psicoterapia Psicodinámica/métodos , Conducta Autodestructiva/prevención & control , Intento de Suicidio/prevención & control , Humanos , Conducta Autodestructiva/psicología , Ideación Suicida , Intento de Suicidio/psicologíaRESUMEN
Some honeys contain the neurotoxin tutin (1) plus hyenanchin (2), 2-(ß-d-glucopyranosyl)tutin (3), and 2-[6'-(α-d-glucopyranosyl)-ß-d-glucopyranosyl]tutin (4). These honeys are made by bees collecting honeydew from passionvine hoppers feeding on the sap of tutu plants ( Coriaria spp.). We report a LC-MS study showing that all these picrotoxanes are of plant, not insect, origin. Hyenanchin was barely detectable and the diglucoside was not detectable in C. arborea leaves, but tutu phloem sap contained all four compounds at concentrations up to the highest found in honeydew. It is proposed that the diglucoside may function as a transport form of tutin, analogous to sucrose transport in phloem.
Asunto(s)
Glicósidos/química , Insectos/química , Magnoliopsida/química , Neurotoxinas/química , Floema/química , Picrotoxina/análogos & derivados , Sesquiterpenos/química , Animales , Cromatografía Liquida/métodos , Miel , Picrotoxina/química , Hojas de la Planta/química , Espectrometría de Masas en Tándem/métodosRESUMEN
In vivo measurements of (14)C tracer distribution have usually involved monitoring the ß(-) particles produced as (14)C decays. These particles are only detectable over short distances, limiting the use of this technique to thin plant material. In the present experiments, X-ray detectors were used to monitor the Bremsstrahlung radiation emitted since ß(-) particles were absorbed in plant tissues. Bremsstrahlung radiation is detectable through larger tissue depths. The aim of these experiments was to demonstrate the Bremsstrahlung method by monitoring in vivo tracer-labelled photosynthate partitioning in small kiwifruit (Actinidia arguta (Siebold & Zucc.) Planch. ex Miq.) plants in response to root pruning. A source shoot, consisting of four leaves, was pulse labelled with (14)CO(2). Detectors monitored import into a fruit and the root system, and export from a source leaf. Repeat pulse labelling enabled the comparison of pre- and post-treatment observations within an individual plant. Diurnal trends were observed in the distribution of tracer, with leaf export reduced at night. Tracer accumulated in the roots declined after approximately 48 h, which may have resulted from export of (14)C from the roots in carbon skeletons. Cutting off half the roots did not affect tracer distribution to the remaining half. Tracer distribution to the fruit was increased after root pruning, demonstrating the higher competitive strength of the fruit than the roots for carbohydrate supply. Increased partitioning to the fruit following root pruning has also been demonstrated in kiwifruit field trials.
Asunto(s)
Actinidia/metabolismo , Metabolismo de los Hidratos de Carbono , Raíces de Plantas/metabolismo , Monitoreo de Radiación/métodos , Partículas beta , Transporte Biológico , Dióxido de Carbono/metabolismo , Radioisótopos de Carbono/análisis , Ritmo Circadiano , Frutas/metabolismo , Hojas de la Planta/metabolismo , Brotes de la Planta/metabolismo , Trazadores Radiactivos , Rayos XRESUMEN
Increasingly, mental health services are delivered through multidisciplinary teams and settings. This creates particular challenges for the development of evidence-based practice guidelines when different professional groups represented within teams might have different traditions and cultures in relation to what counts as 'evidence', and how that might be synthesized to produce guidance that supports best practice across professional divides. These challenges are explored in relation to integration between health and social care services, where social work in particular has traditionally expressed scepticism about guideline development where it does not incorporate knowledge drawn from qualitative research and perspectives of stakeholders such as service users and carers. This article takes the NICE-SCIE guideline on dementia care as an exemplar of how an integrated process of guideline development can deliver guidance for best practice across integrated mental health services. Finally, some of the issues still facing inter-professional guideline development are considered, and pointers given to eclectic approaches that are beginning to emerge from within social work.
Asunto(s)
Demencia/psicología , Demencia/rehabilitación , Guías de Práctica Clínica como Asunto/normas , Asistencia Social en Psiquiatría/normas , Medicina Basada en la Evidencia/métodos , Humanos , Programas Nacionales de Salud/organización & administración , Reino UnidoRESUMEN
This work aims to understand how Vitis vinifera (Chardonnay) vines prioritise the export and distribution of recently fixed photoassimilate between root tissue, fruit, and defence, following the elicitation of a defence response. Jasmonic acid (JA) and its methyl ester, MeJA, are endogenous plant hormones, known collectively as jasmonates, that have signalling roles in plant defence and consequently are often used to prime plant defence systems. Here, we use exogenous jasmonate application to mature source leaves of Chardonnay grapevines to elucidate the prioritisation strategy of carbon allocation between plant defence and growth. Our results demonstrate that jasmonate application to Chardonnay leaves can elicit a defence response to Botrytis cinerea, but the effect was localised to the jasmonate-treated area. We found no evidence of a systemic defence response in non-treated mature leaves or young growing tissue. JA application reduced the photosynthetic rate of the treated leaf and reduced the export rate of recently fixed carbon-11 from the leaf. Following JA application, a greater proportion of available recently fixed carbon was allocated to the roots, suggesting an increase in sink strength of the roots. Relative sink strength of the berries did not change; however, an increase in berry sugar was observed seven days after JA treatment. We conclude that the data provide evidence for a "high sugar resistance" model in the mature treated leaves of the vine, since the export of carbon was reduced to ensure an elevated defence response in the treated leaf. The increase in berry sugar concentration seven days after treatment can be explained by the initial prioritisation of a greater portion of the exported carbon to storage in the roots, making it available for remobilisation to the berries once the challenge to defence had passed.
RESUMEN
Consumer acceptance of fruit is determined by size, flavour and ripeness. In this study we investigated how altering the carbohydrate supply to Actinidia chinensis var. chinensis 'Zesy002' kiwifruit altered the balance between growth and accumulation of metabolites. Canes were phloem girdled and fruit thinned to a leaf-to-fruit ratio (L:F) of either 2 (Low carbohydrate) or 6 (High carbohydrate) at either 38 (Early) or 86 (Late) days after anthesis (DAA) and compared with ungirdled control canes with a L:F of 3. Fruit growth, metabolite accumulation, cytokinin concentrations and maturation were monitored and the sensory attributes of ripe fruit were assessed. The final weight of Early-High and Late-High carbohydrate fruit was 38% and 16% greater compared with control fruit. High carbohydrate fruit had increased starch, soluble sugar and cytokinin concentrations and fruit began to mature earlier and those with a Low carbohydrate had decreased concentrations and matured later compared with control fruit. Control fruit were described by consumers as more acidic and under-ripe compared with those from Early-High carbohydrate canes, but as sweeter than those from Low carbohydrate canes. This study showed that carbohydrate supply can have a major impact on the growth, sugar accumulation and maturity of 'Zesy002' fruit sinks.
RESUMEN
BACKGROUND: Plant microRNAs (miRNAs) are a class of small, non-coding RNAs that play an important role in development and environmental responses. Hundreds of plant miRNAs have been identified to date, mainly from the model species for which there are available genome sequences. The current challenge is to characterise miRNAs from plant species with agricultural and horticultural importance, to aid our understanding of important regulatory mechanisms in crop species and enable improvement of crops and rootstocks. RESULTS: Based on the knowledge that many miRNAs occur in large gene families and are highly conserved among distantly related species, we analysed expression of twenty-one miRNA sequences in different tissues of apple (Malus x domestica 'Royal Gala'). We identified eighteen sequences that are expressed in at least one of the tissues tested. Some, but not all, miRNAs expressed in apple tissues including the phloem tissue were also detected in the phloem sap sample derived from the stylets of woolly apple aphids. Most of the miRNAs detected in apple phloem sap were also abundant in the phloem sap of herbaceous species. Potential targets for apple miRNAs were identified that encode putative proteins shown to be targets of corresponding miRNAs in a number of plant species. Expression patterns of potential targets were analysed and correlated with expression of corresponding miRNAs. CONCLUSIONS: This study validated tissue-specific expression of apple miRNAs that target genes responsible for plant growth, development, and stress response. A subset of characterised miRNAs was also present in the apple phloem translocation stream. A comparative analysis of phloem miRNAs in herbaceous species and woody perennials will aid our understanding of non-cell autonomous roles of miRNAs in plants.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Malus/genética , Malus/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Animales , Áfidos/clasificación , Áfidos/metabolismo , Arabidopsis/genética , Secuencia de Bases , Perfilación de la Expresión Génica , Malus/clasificación , Floema/metabolismo , ARN Mensajero/metabolismoRESUMEN
The phloem is the long-distance transport system for photoassimilates within the plant. The vulnerability of the phloem tissue to blockage and damage makes it technically difficult to study, which has made it one of the least understood tissues. Transport of solution through the phloem appears to be by osmotically driven bulk flow, making an understanding of phloem hydrostatic pressure important in our comprehension of phloem flow mechanics. Here we describe a method of making in vivo direct transient measurements of phloem hydrostatic pressure using excised aphid stylets to directly access the phloem.
Asunto(s)
Áfidos , Interacciones Huésped-Parásitos , Presión Hidrostática , Floema/fisiología , Animales , Floema/parasitologíaRESUMEN
Child sexual abuse (CSA) is a trauma that affects males in substantial numbers, sometimes in ways that are gender-specific (e.g., compromised masculine identity, confusion regarding sexuality). Much of the identification of the male-specific outcomes has been derived from practitioner experience and small qualitative studies. The current study explores gender-specific outcomes and describes the development of a scale to measure the effects of CSA on men. First, qualitative interviews with 20 men who were sexually abused in childhood were thematically analyzed. The emergent themes of sexuality, self-concept, psychological and emotional well-being, and social functioning were used to construct a 30-item instrument which was later completed by 147 men with histories of CSA. The dimensionality of the 30 items was then assessed for suitability as scales using confirmatory factor analysis (CFA). The final instrument, the Male Sexual Abuse Effects Scale (MSAES), combines three subscales: Negative Identity, Guilt and Self-Blame, and Psychological and Emotional Well-Being. Items concerning masculine identity were shown to be valid in the scale. MSAES scores were compared with the General Health Questionnaire-28 (GHQ-28) and found to be significantly correlated. GHQ-28 clinical thresholds were applied to differentiate clinical from nonclinical cases; an independent-samples t test showed that the clinical cases from the GHQ-28 had high scores on the MSAES. The new scale has the potential to help clinicians and researchers identify men who have been severely affected by CSA and who should be of clinical concern.
RESUMEN
BACKGROUND: The study reviewed the disciplinary composition of community mental health teams (CMHTs) and conducted a national survey of mental health providers in England and Wales to explore the determinants of the social care component of CMHTs. METHODS: A comprehensive literature review and a national survey of NHS mental health Trusts in England and Wales. RESULTS: The literature review showed that team composition was rarely well justified with regard to effectiveness, despite some evidence that greater professional diversity (i.e. inclusion of social workers) was associated with higher effectiveness. Forty-two mental health Trusts responded (53.2%) to the survey. There were no staffing differences between responding and non-responding Trusts. Social workers accounted for 19.3% of the staffing total. Nurses formed a third of the workforce and social support workers made up a further 10%. We found that there continues to be a shortage (compared to policy targets and previous research) of psychiatrists, psychologists and occupational therapists, whereas the numbers of nurses employed far exceeds their target numbers. Total staffing numbers appeared to be slightly higher in Trusts citing 'financial resources' as a determining factor of team composition. Despite being statistically non-significant, the 'financial resource' effect was of medium magnitude. Similarly, there was a non-significant but approaching medium-sized effect of higher numbers of social care support staff when guidance was cited as a rationale for CMHT composition. There was a non-significant (P = 0.076) medium magnitude (η(2)(p) = 0.067) trend towards higher staff numbers in more integrated trusts that did not cite financial resources as a driver of team composition. CONCLUSIONS: If service recipients are to gain equal access to appropriately staffed services, further attention needs to be paid to supporting an adequately skilled multidisciplinary workforce. The workforce needs to be organised in a way that best provides for local needs rather than a service based largely on the existing supply of different professionals and disjointed workforce planning.
Asunto(s)
Servicios Comunitarios de Salud Mental/organización & administración , Grupo de Atención al Paciente/organización & administración , Medicina Estatal , Eficiencia Organizacional , Inglaterra , Encuestas de Atención de la Salud , Investigación sobre Servicios de Salud , Humanos , Personal de Enfermería/estadística & datos numéricos , Apoyo Social , Servicio Social/estadística & datos numéricos , GalesAsunto(s)
Trastorno de Personalidad Antisocial/diagnóstico , Trastornos de la Conducta Infantil/diagnóstico , Trastorno de la Conducta/diagnóstico , Psicoterapia/métodos , Adolescente , Trastorno de Personalidad Antisocial/terapia , Niño , Trastornos de la Conducta Infantil/terapia , Preescolar , Trastorno de la Conducta/terapia , Medicina Basada en la Evidencia , Humanos , Guías de Práctica Clínica como Asunto , Factores de Riesgo , Reino UnidoAsunto(s)
Trastorno Autístico/terapia , Manejo de la Enfermedad , Adolescente , Niño , Preescolar , Medicina Basada en la Evidencia , Humanos , Reino Unido , Adulto JovenRESUMEN
According to the Münch hypothesis, a flow of solution through the sieve tubes is driven by a hydrostatic pressure difference between the source (or collection) phloem and the sink (or release) phloem. A high hydrostatic pressure is maintained in the collection phloem by the active uptake of sugar and other solutes, with a concomitant inflow of water. A lower pressure is maintained in the release phloem through solute unloading. In this work we directly test the role of solute uptake in creating the hydrostatic pressure associated with phloem flow. Solute loading into the phloem of mature leaves of barley and sow thistle was reduced by replacing the air supply with nitrogen gas. Hydrostatic pressure in adjacent sieve elements was measured with a sieve-element pressure probe, a cell pressure probe glued to the exuding stylet of aphids that had been feeding from the phloem. Sieve element sap was sampled by aphid stylectomy; sap osmotic pressure was determined by picolitre osmometry and its sugar concentration by enzyme-linked fluorescence assays. Samples were taken with a time resolution of ~2-3 min. In accordance with Münch's proposal a drop in osmotic and hydrostatic pressure in the source phloem following treatment of the source leaf with N2 was observed. A decrease in sugar concentration was the major contributor to the change in osmotic pressure. By observing these variables at a time resolution of minutes we have direct observation of the predictions of Münch.
RESUMEN
According to the Münch hypothesis, solution flow through the phloem is driven by a hydrostatic pressure gradient. At the source, a high hydrostatic pressure is generated in the collection phloem by active loading of solutes, which causes a concomitant passive flow of water, generating a high turgor pressure. At the sink, solute unloading from the phloem keeps the turgor pressure low, generating a source-to-sink hydrostatic pressure gradient. Localised changes in loading and unloading of solutes along the length of the transport phloem can compensate for small, short-term changes in phloem loading at the source, and thus, maintain phloem flow to the sink tissue. We tested directly the hydrostatic pressure regulation of the sieve tube by relating changes in sieve tube hydrostatic pressure to changes in solute flow through the sieve tube. A sudden phloem blockage was induced (by localised chilling of a 1-cm length of stem tissue) while sieve-tube-sap osmotic pressure, sucrose concentration, hydrostatic pressure and flow of recent photosynthate were observed in vivo both upstream and downstream of the block. The results are discussed in relation to the Münch hypothesis of solution flow, sieve tube hydrostatic pressure regulation and the mechanism behind the cold-block phenomenon.
RESUMEN
This work relates solute import to elongating root cells in barley to the water relations of the symplastic pathway under conditions of varied plant K+ status. K+ is a major constituent of phloem sieve element (SE) sap, and as an osmoticum, it is believed to have a role in maintaining SE hydrostatic pressure and thus sap flow from source to sink tissue. The hypothesis that the solute import to elongating root cells is linked to pressure driven flow from the sieve tube is examined.Plants were grown in solutions containing either 0.05 mM (low K) or 2.05 mM (high K) K+ concentration. Solute import to the root elongation zone was estimated from biomass accumulation over time accounting for respiration and root elongation rate. SE sap K+ concentration was measured using X-ray microanalyses and osmotic pressure by picolitre osmometry. SE hydrostatic pressure was measured directly with a pressure probe glued onto an excised aphid stylet. Elongating root cell hydrostatic pressure was measured using a cell pressure probe.The low-K plants had lower SE K+ concentration and SE hydrostatic pressure compared to the high-K plants, but the elongating root cell hydrostatic pressure was similar in both treatments, thus the pressure difference between the SE and elongating root cells was less in the low-K plants compared to the high-K plants.The solute import rate to elongating root cells was lower in the low K plants and the reduction could be accounted for as a pressure driven solute flux, with a reduction both in the pressure difference between root sieve elements and elongating cells, and in the sap concentration.
RESUMEN
It has been observed that extension growth in maize roots is almost stopped by exposure to 5 mm d-galactose in the root medium, while the import of recent photoassimilate into the entire root system is temporarily promoted by the same treatment. The aim of this study was to reconcile these two apparently incompatible observations. We examined events near the root tip before and after galactose treatment since the tip region is the site of elongation and of high carbon deposition in the root. The treatment rapidly decreased root extension along the whole growing zone. In contrast, turgor pressure, measured directly with the pressure probe in the cortical cells of the growing zone, rapidly increased by 0.15 MPa within the first hour following treatment, and the increase was maintained over the following 24 h. Both tensiometric measurements and a comparison of turgor pressure with local growth rate demonstrated that a rapid tightening of the cell wall caused the reduction in growth. Single cell sampling showed cell osmotic pressure increased by 0.3 MPa owing to accumulation of both organic and inorganic solutes. The corresponding change in cell water potential was a rise from -0.18 MPa to approximately zero. More mature cells at 14 mm from the root tip (just outside the growing region) showed a qualitatively similar response.