985 resultados para Climate Changes
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Coffea canephora is one of the most economically important coffee species and in Brazil, Conilon is the most widely cultivated plant of this species. Abiotic stresses such as temperature variations and drought periods are factors that significantly affect their production and tend to worsen with globally recognized climate changes. In an attempt to understand the molecular responses of coffee plants in water deficit conditions, recent studies have identified candidate genes (CGs) as CcDREB1D. This gene showed increased expression in response to drought in the leaves of clone 14 (drought tolerant) in relation to the clone 22 (sensitive to drought) of C. canephora Conilon. Based on these results, the identification of DREB genes and their subgroups (SGs) of C. canephora, the objective is to analyze in silico and also in vivo these genes expression in leaf and root of tolerant (14, 73 and 120) and sensitive clones (22) of C. canephora Conilon submitted or not to a water deficit. In silico expressions of all DREB genes were analyzed from the Coffee Genome Hub Database and in vivo expression was performed by the technique "reverse transcription-quantitative PCR" (RT-qPCR). In silico gene expression analysis was possible to identify DREB genes with potential responses to abiotic stresses, corroborating some validated in vivo results. In this analysis, several genes showed differential expression in response to drought among the SGs (IIV), the tolerant and sensitive clones and the leaf and root. These differentially expressed genes were identified as potential CGs and among them, it was found that most tolerant clones showed increased expression in relation to sensitive in response to drought, with higher expression levels for clones 14 and 73. These highest levels were observed in leaves compared to the roots and SG-I stood at greater number of genes expressed in response to drought. These results suggest that DREB CGs, as Cc05_g06840, Cc02_g03420 e Cc08_g13960, play an important role in the regulatory mechanisms of response to drought in C. canephora Conilon.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Ciência e Tecnologia de Materiais - FC
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Pós-graduação em Geografia - IGCE
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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There are strong uncertainties regarding LAI dynamics in forest ecosystems in response to climate change. While empirical growth & yield models (G&YMs) provide good estimations of tree growth at the stand level on a yearly to decennial scale, process-based models (PBMs) use LAI dynamics as a key variable for enabling the accurate prediction of tree growth over short time scales. Bridging the gap between PBMs and G&YMs could improve the prediction of forest growth and, therefore, carbon, water and nutrient fluxes by combining modeling approaches at the stand level.Our study aimed to estimate monthly changes of leaf area in response to climate variations from sparse measurements of foliage area and biomass. A leaf population probabilistic model (SLCD) was designed to simulate foliage renewal. The leaf population was distributed in monthly cohorts, and the total population size was limited depending on forest age and productivity. Foliage dynamics were driven by a foliation function and the probabilities ruling leaf aging or fall. Their formulation depends on the forest environment.The model was applied to three tree species growing under contrasting climates and soil types. In tropical Brazilian evergreen broadleaf eucalypt plantations, the phenology was described using 8 parameters. A multi-objective evolutionary algorithm method (MOEA) was used to fit the model parameters on litterfall and LAI data over an entire stand rotation. Field measurements from a second eucalypt stand were used to validate the model. Seasonal LAI changes were accurately rendered for both sites (R-2 = 0.898 adjustment, R-2 = 0.698 validation). Litterfall production was correctly simulated (R-2 = 0.562, R-2 = 0.4018 validation) and may be improved by using additional validation data in future work. In two French temperate deciduous forests (beech and oak), we adapted phenological sub-modules of the CASTANEA model to simulate canopy dynamics, and SLCD was validated using LAI measurements. The phenological patterns were simulated with good accuracy in the two cases studied. However, IA/max was not accurately simulated in the beech forest, and further improvement is required.Our probabilistic approach is expected to contribute to improving predictions of LAI dynamics. The model formalism is general and suitable to broadleaf forests for a large range of ecological conditions. (C) 2014 Elsevier B.V. All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The genus Brachycephalus is endemic to the Atlantic rainforest and is distributed mainly in the southeastern and southern Brazil. Currently, it has 17 recognized species, most of them, associated with mountainous habitats along the Serra do Mar and Serra da Mantiqueira ridges. Here we use an ecological niche modelling approach based on climatic variables, to assess the potential niche of the mountainous species of this genus. The model generated was then projected to future scenarios considering the last IPCC report, in order to estimate the impacts of climate changes on these species distribution. Results show a decrease in the total suitable area for the mountainous Brachycephalus species, as well as tendencies already observed for other organisms, such as, pole and upward migrations. A southern area on Planalto de Paranapiacaba increases in suitability for these species. We suggest special efforts on new surveys and conservation on the northern part of their distribution, once this seems to be the region more affected by climate changes on the projected scenarios
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The Atlantic forest has a large number of endemic species due to the varieties of environments, altitudes, and climates found along its distribution. The species Brachycephalus ephippium is an example of endemic anuran from this forest formation, occurring in the states of São Paulo, Rio de Janeiro and Minas Gerais, between 750 and 1200 m altitude. This species is abundant in the Serra do Japi, an Atlantic Forest remnant, which houses high biodiversity, located in Jundiaí city, between three big urban centers in the state of São Paulo. This remnant, which has altitude ranging between 700 and 1300 meters, is threatened by global climate changes and, spite of legally protected, by intense pressure of urbanization. The aim of the present study was to verify the association between of environmental variables with the abundance and distribution of B. ephippium in the Serra do Japi. The air relative humidity showed a positive correlation with the presence of B. ephippium individuals and the best model to explain the abundance involved air relative temperature and litter temperature. These results allowed the investigation of the environment use by this species and can be used to provide conservationist actions
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Pythiosis is caused by the oomycetous Pythium insidiosum and affect domestic and wild animals and man. The presence of water and vegetal material is fundamental for its life cycle in nature. The biflagellate zoospore are the infective form of this pathogen. The lesions are generally of granulomatous aspect, which frequently may be contaminated by secondary bacterial infection in skin and subcutaneous tissue. Dissemination to systemic tissues may also occur and it may be due to the spread of the pathogen from cutaneous lesions, as well as a primary source of infection. Clinical signs depend on the affected tissue. Diagnosis of pythiosis is based on the clinical manifestations, histopathological sections and culture of the pathogen. Serological tests may also be employed and more recently molecular biology has been introduced as a sensitive, specific and a rapid method for conclusive diagnosis. Treatment is often difficult and extensive surgery procedures are required, however, depending on the anatomic region and size of the lesion, such procedure is unfeasible and relapses are frequent. Due to the climate changes, which has contributed to increase the incidence of pythiosis, it is necessary the search for new therapeutic protocols
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)