41 research outputs found

    The role of abscisic acid and water relations in drought responses of subterranean clover

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    The role of water relations and abscisic acid (ABA) in the responses to drought were studied in a mediterranean forage crop, Trifolium subterraneum L. under field conditions. soil and plant water status, leaf gas exchange parameters, and xylem sap ABA content were determined at different times during a long-term soil drying episode in irrigated and droughted plants. The diurnal time-courses of these parameters were also measured at the end of a drought period. In response to soil drying stomatal conductance (g) was reduced early to 50% that of irrigated plants before any substantial change in water potential was detected. A close logarithmic regression between photosynthesis rate (A) and g was present. For the first weeks of drought the decline in A was less pronounced than in g, thus increasing water use efficiency. Stomatal conductance during diurnal time-courses showed no consistent relationships with respect to either ABA or leaf water potential. throughout the experimental period dependence of g on leaf water status was evident from the tight correlation (r(2) = 0.88, P < 0.01) achieved between stomatal conductance and midday water potential, but the correlation was also high when comparing g with respect to ABA content in xylem sap (r(2) = 0.83, P < 0.001). However, the stomata from drought acclimated plants were apparently more sensitive to xylem ABA content. For similar xylem ABA concentrations stomatal conductance was significantly higher in irrigated than in water-stressed plants.info:eu-repo/semantics/publishedVersio

    Pedigree analysis of 220 almond genotypes reveals two world mainstream breeding lines based on only three different cultivars

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    Loss of genetic variability is an increasing challenge in tree breeding programs due to the repeated use of a reduced number of founder genotypes. However, in almond, little is known about the genetic variability in current breeding stocks, although several cases of inbreeding depression have been reported. To gain insights into the genetic structure in modern breeding programs worldwide, marker-verified pedigree data of 220 almond cultivars and breeding selections were analyzed. Inbreeding coefficients, pairwise relatedness, and genetic contribution were calculated for these genotypes. The results reveal two mainstream breeding lines based on three cultivars: “Tuono”, “Cristomorto”, and “Nonpareil”. Descendants from “Tuono” or “Cristomorto” number 76 (sharing 34 descendants), while “Nonpareil” has 71 descendants. The mean inbreeding coefficient of the analyzed genotypes was 0.041, with 14 genotypes presenting a high inbreeding coefficient, over 0.250. Breeding programs from France, the USA, and Spain showed inbreeding coefficients of 0.075, 0.070, and 0.037, respectively. According to their genetic contribution, modern cultivars from Israel, France, the USA, Spain, and Australia trace back to a maximum of six main founding genotypes. Among the group of 65 genotypes carrying the Sf allele for self-compatibility, the mean relatedness coefficient was 0.125, with “Tuono” as the main founding genotype (24.7% of total genetic contribution). The results broaden our understanding about the tendencies followed in almond breeding over the last 50 years and will have a large impact into breeding decision-making process worldwide. Increasing current genetic variability is required in almond breeding programs to assure genetic gain and continuing breeding progress

    Procalcitonin (PCT) levels for ruling-out bacterial coinfection in ICU patients with influenza: A CHAID decision-tree analysis

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    Objectives: To define which variables upon ICU admission could be related to the presence of coinfection using CHAID (Chi-squared Automatic Interaction Detection) analysis. Methods: A secondary analysis from a prospective, multicentre, observational study (2009-2014) in ICU patients with confirmed A(H1N1)pdm09 infection. We assessed the potential of biomarkers and clinical variables upon admission to the ICU for coinfection diagnosis using CHAID analysis. Performance of cut-off points obtained was determined on the basis of the binominal distributions of the true (+) and true (−) results. Results: Of the 972 patients included, 196 (20.3%) had coinfection. Procalcitonin (PCT; ng/mL 2.4 vs. 0.5, p < 0.001), but not C-reactive protein (CRP; mg/dL 25 vs. 38.5; p = 0.62) was higher in patients with coinfection. In CHAID analyses, PCT was the most important variable for coinfection. PCT <0.29 ng/mL showed high sensitivity (Se = 88.2%), low Sp (33.2%) and high negative predictive value (NPV = 91.9%). The absence of shock improved classification capacity. Thus, for PCT <0.29 ng/mL, the Se was 84%, the Sp 43% and an NPV of 94% with a post-test probability of coinfection of only 6%. Conclusion: PCT has a high negative predictive value (94%) and lower PCT levels seems to be a good tool for excluding coinfection, particularly for patients without shock

    The family competence approach, an experience of socio-educational work with families

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    Introduction. The Spanish adaptation of the Family Competence Program (FCP) offers a way of working socio-educationally with families that need to improve their functionality. The socio-educational methodologies for working with families applied by FCP, through medium term processes (14 weeks), were designed in the framework of the family competence approach, in accordance with rigorous criteria. The correct application of the FCP, according to its contents and methodologies, offers good results proven in primary care social services with families in a difficult situation. Method. Controlled applications of the FCP were conducted, using a quasi-experimental design consisting of a control group and pre-test and post-test measurements. The sample was made up of 217 families which took part in the programme and 14 families that participated in a control group. Validated instruments were applied to carry out the assessments of the methodological processes and the assessments of the families. Results. Positive changes can be observed in six fundamental family factors. The quality of the methodology and fidelity to the FCP in the application obtain excellent results. Methodological and fidelity indicators correlate positively with the results of the families. This relationship can be considered underrated due to the problems present in the families. Discussion. The self-assessments of the participants and of the professionals, even though they were rigorously controlled, may represent a source of bias. In the short term the results may represent an overrating. Either way, the FCP is an excellent socio-educational program for preventive work with families with functional difficulties

    Autoconcepto, estilos de afrontamiento y conducta del alumnado universitario

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    La autoaceptación y una visión positiva de uno mismo y los demás favorecen el acercamiento y las relaciones interpersonales positivas y satisfactorias. El presente estudio explora las relaciones entre el autoconcepto y el estilo de afrontamiento, analizándolos en la relación educativa. Se estudió una muestra de 133 alumnos de la Facultad de Educación de la Universidad de las Islas Baleares a lo largo del curso 2002-2003. Los resultados indican la relación entre el autoconcepto y el estilo de afrontamiento con la motivación y la satisfacción; así como la importancia de la satisfacción y la motivación en el seguimiento de los estudios y la dedicación a los mismos

    Long term water stress inactivates Rubisco in subterranean clover

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    In long-term field experiments, during consecutive years, microswards of subterranean clover were irrigated to minimise water deficits or subjected to progressively increasing drought over 30 days. Both leaf water potential and relative water content steadily decreased during the experiments. Plants affected by drought grew more slowly and photosynthesis was decreased. Photosynthetic rate (A) and Rubisco were analysed in relation to midday water potentials and relative water contents. The difference in A between droughted and irrigated plants increased progressively, in part as a result of decreased stomatal conductance and CO2 concentration within leaf (Ci). However, A-Ci curves suggest that the photosynthetic capacity in plants experiencing long-term stress was reduced by 50% when compared with irrigated plants. Drought decreased both the initial and the total Rubisco activity per unit area in a similar way but did not reduce the amount of Rubisco protein per unit leaf area. Thus, the specific activity of Rubisco, rather than its activation state, decreased suggesting that under water stress the active sites were blocked by inhibitors
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