ABSTRACT
As telas de sombreamento são amplamente utilizadas para controlar a radiação solar excessiva. Novos aditivos, dispersivos e elementos refletivos têm sido incorporados nas telas durante o processo de fabricação para modificar a qualidade espectral da radiação e obter respostas fisiológicas desejadas. O objetivo do presente trabalho foi avaliar o efeito de diferentes telas de sombreamento no desenvolvimento de mudas de tomateiro (Solanum lycopersicum L. cv. Caline IPA 6). Foram utilizadas quatro telas com 50% de sombreamento (preta, aluminizada, vermelha e cinza). O delineamento experimental foi inteiramente casualizado, com quatro tratamentos e quatro repetições. As variáveis estudadas foram: a altura e diâmetro final das plantas, massa de matéria seca de raiz e parte aérea, índice de clorofila, radiação fotossinteticamente ativa e temperatura do ar. As telas influenciaram no microclima e nas variáveis de crescimento do tomateiro. De acordo com os resultados a tela aluminizada apresentou melhor desempenho que às telas fotosseletivas e preta, embora estudos complementares necessitem serem feitos para maior avaliação do potencial de uso das telas em cultivo com tomateiro.
The shade nets are widely used to control excessive solar radiation. Recently, new additives, dispersive and reflective elements have been incorporated into the netting materials during manufacturing to modify the spectral quality of the radiation in order to reach desired physiological crop responses. The aim of this study was to evaluate the effect of different shade nets in developing seedlings of tomato (Solanum lycopersicum L. cv. Caline IPA 6). Four nets with 50% shading (black, aluminated, red and gray photo-selective nets) were studied. The experimental design was completely randomized with four treatments and four replications. The variables studied were: height and diameter of the final plants, the dry mass of roots and shoots, chlorophyll index, the photosynthesis photon flux density and air temperature. The nets influenced the microclimate variables and the growth of tomato seedlings. According to the results, the aluminated net performed better than the photo-selectives nets and black, although further studies need to be done for further evaluation of the potential use of screens with tomato cultivation.
Subject(s)
Crop Production , Solanum lycopersicum , Solar RadiationABSTRACT
BACKGROUND AND AIMS: Erythrina speciosa is a Neotropical tree that grows mainly in moist habitats. To characterize the physiological, morphological and growth responses to soil water saturation, young plants of E. speciosa were subjected experimentally to soil flooding. METHODS: Flooding was imposed from 2 to 4 cm above the soil surface in water-filled tanks for 60 d. Non-flooded (control) plants were well watered, but never flooded. The net CO(2) exchange (A(CO2)), stomatal conductance (g(s)) and intercellular CO(2) concentration (C(i)) were assessed for 60 d. Soluble sugar and free amino acid concentrations and the proportion of free amino acids were determined at 0, 7, 10, 21, 28 and 45 d of treatments. After 28, 45 and 60 d, dry masses of leaves, stems and roots were determined. Stem and root cross-sections were viewed using light microscopy. KEY RESULTS: The A(CO2) and g(s) were severely reduced by flooding treatment, but only for the first 10 d. The soluble sugars and free amino acids increased until the tenth day but decreased subsequently. The content of asparagine in the roots showed a drastic decrease while those of alanine and gamma-aminobutyric increased sharply throughout the first 10 d after flooding. From the 20th day on, the flooded plants reached A(CO2) and g(s) values similar to those observed for non-flooded plants. These events were coupled with the development of lenticels, adventitious roots and aerenchyma tissue of honeycomb type. Flooding reduced the growth rate and altered carbon allocation. The biomass allocated to the stem was higher and the root mass ratio was lower for flooded plants when compared with non-flooded plants. CONCLUSIONS: Erythrina speciosa showed 100 % survival until the 60th day of flooding and was able to recover its metabolism. The recovery during soil flooding seems to be associated with morphological alterations, such as development of hypertrophic lenticels, adventitious roots and aerenchyma tissue, and with the maintenance of neutral amino acids in roots under long-term exposure to root-zone O(2) deprivation.
Subject(s)
Erythrina/growth & development , Erythrina/physiology , Soil , Water/pharmacology , Amino Acids/metabolism , Biomass , Carbohydrate Metabolism , Carbon Dioxide/metabolism , Erythrina/anatomy & histology , Gases/metabolism , Photosynthesis , Plant Roots/cytology , Plant Roots/metabolism , Plant Stems/anatomy & histology , Plant Stems/cytology , Plant Stems/metabolism , Plant Stomata/physiology , SolubilityABSTRACT
Apresentamos um caso de abscesso cerebelar secundário a otite média crônica, localizado no hemisfério cerebelar direito, em uma paciente pediátrica, que foi tratado clinicamente. Obtendo resoluçäo sem necessidade de cirurgia. A antibioticoterapia foi escolhida segundo critérios da literatura para os agentes etiológicos mais prováveis. Discutimos a patogênese, histopatogênese, o quadro clínico, o diagnóstico e as formas de tratamento dos abscessos do sistema nervoso central
