Journal of Biotechnology and Biodiversity
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Shoot tip and cotyledon explants of Eucalyptus saligna Sm. cultivated on different kanamycin levels
Get PDFAn efficient selec tive agent helps to obtain transgenic plant s; the most used selective agent for genetic transformation of Eucalypt is kanamycin. The aim of this research was to determine ideal dose of kanamycin in shoot tip and cotyledon explants of E. saligna for use as selective agent in genetic transformation. Two experiments were carried out, first in order to test effects of the kanamycin in cotyledons and second, in order to test effects of the kanamycin in shoot tip. In the cotyledons experiment were tested 0, 12.5, 25, 37.5 and 50 mg.L-1 kanamycin on a callus formation medium and for shoot tip were tested 50, 75, 100, 125 and 150 mg.L-1 kanamycin on a multiplication medium. Cotyledons can be selected more quickly than shoot tip, moreover needs lower kanamycin levels than shoot tip, what results more speed and economy during genetic transformation process. It is probable that levels lower than 12.5 mg.L-1 kanamycin must be ideal for the cotyledons selection and 50 mg.L-1kanamycin for shoot tip.Um agente seletivo eficiente é determinante no processo de obtenção de plantas transgênicas; o agente seletivo mais usado para transformação genética de eucalipto é a canamicina. O objetivo desse trabalho foi determinar as concentrações ideias de canamicina em cotilédones e em ápices caulinares de Eucalyptus salignapara uso como agente seletivo para transformação genética. Dois experimentos foram conduzidos, um para testar os efeitos da canamicina nos cotilédones e o outro para testar os efeitos da canamicina nos ápices caulinares. No experimento com cotilédones foram testadas as seguintes concentrações: 0, 12.5, 25, 37.5 and 50 mg.L-1 de canamicina em meio para formação de calos e no experimento de ápices caulinares foram testadas as concentrações de 50, 75, 100, 125 e 150 mg.L-1 de canamicina em meio de multiplicação. Cotilédones podem ser selecionados mais rapidamente do que os ápices caulinares, além disso necessitam de menores concentrações de canamicina, o que resultaria maior velocidade e economia durante o processo de transformação genética. É provável que níveis inferiores que 12,5 mg.L-1 de canamicina sejam ideais para a seleção de cotilédones. Para a seleção de ápices caulinares podem ser usados 50 mg.L-1de canamicina
Influência do lenho de tração nas propriedades físicas da madeira de Eucalyptus sp.
Get PDFThe reaction wood is formed in an attempt to remain upright tree in response to the action of forces such as winds, irregular crown or slope of the land that tend to incline it. In hardwoods, as in Eucalyptus, this type of wood is called tension wood and occurs in the region of the stem facing the face of force application. Indicative of the presence of this type of wood is the high shrinkage and basic density compared to normal wood. Once the basic density and shrinkage are parameters for determining the quality of the wood, this study aimed to evaluate the variation of basic density and shrinkage of opposite and tension wood along the radius in four species of Eucalyptus sp. Four tree species Eucalyptus camaldulensis, Eucalyptus maculata, Eucalyptus pilularis and Eucalyptus urophylla, with 32 years of age, were taken from an experimental planting of the Federal University of Lavras. Specimens were made to represent the diametrical variation of the opposite of tension wood in disks cut at the dbh. The results indicate that the properties of radial, tangential and volumetric shrinkage, coefficient of anisotropy and basic density did not differ statistically between the tensionand opposite wood.The reaction wood is formed in an attempt to remain upright tree in response to the action of forces such as winds, irregular crown or slope of the land that tend to incline it. In hardwoods, as in Eucalyptus, this type of wood is called tension wood and occurs in the region of the stem facing the face of force application. Indicative of the presence of this type of wood is the high shrinkage and basic density compared to normal wood. Once the basic density and shrinkage are parameters for determining the quality of the wood, this study aimed to evaluate the variation of basic density and shrinkage of opposite and tension wood along the radius in four species of Eucalyptus sp. Four tree species Eucalyptus camaldulensis, Eucalyptus maculata, Eucalyptus pilularis and Eucalyptus urophylla, with 32 years of age, were taken from an experimental planting of the Federal University of Lavras. Specimens were made to represent the diametrical variation of the opposite of tension wood in disks cut at the dbh. The results indicate that the properties of radial, tangential and volumetric shrinkage, coefficient of anisotropy and basic density did not differ statistically between the tensionand opposite wood