Leucaena is an exotic fabaceae that has a much diversified utilization, highlighting the reforesting of degraded areas for the erosion control. For presenting a quite slow growth, the success of its cultivation is related to the sowing and seed emergency, that consequently require the utilization of methods of overcoming physic dormancy in seed germination to succeed. This paper aimed evaluates the effect of methods of overcoming dormancy on seed germination and on initial development of leucaena plantlet. The treatments used were: Witness (with no intervention); mechanic scarification with sandpaper number 100; immersion in H2SO4 (95 %) for 4 minutes and immersion in H2O at 80°C for 15 minutes. The mechanic scarification with sandpaper and water at 80ºC for 15 minutes presented the best results to percentage of germination. Although to index of speed emergency and plantlet height, the scarification was better.
O presente estudo objetivou avaliar possíveis alterações nas propriedades das madeiras de Eucalyptus cloeziana e E. grandis modificadas termicamente sob condições hidrotérmicas e de congelamento. Foram amostradas cinco árvores de cada espécie com 20 anos de idade, sendo retirada de cada árvore a primeira tora de 3 m. Foram confeccionados 12 corpos de prova próximos à casca e 12 próximos à medula para cada espécie, com dimensões de 2,0 x 2,0 x 30,0 cm, totalizando 48 corpos de prova. Foram realizados os ensaios de flexão dinâmica, colorimetria e espectroscopia no infravermelho por reflectância total atenuada. Os métodos de tratamento térmico empregados não prejudicaram as propriedades mecânicas da madeira e não afetaram as suas massas específicas aparentes. O tratamento de aquecimento em água implicou em maiores variações das propriedades químicas da madeira. Essas variações, possivelmente, contribuíram para as mudanças de cor na madeira.
Wood is rich in organic compounds; thus, it is susceptible to attacks by several deteriorating agents because they acknowledge such attacks as a necessary energy supply. Fungi stand out among these agents since they can attack the wood in trees (before felling) and in several post-felling stages. Fungi are biological agents that use organic compounds as food sources, and that is the reason why they degrade most chemical components found in wood. Wood attacked by fungi suffers significant value loss, since these degrading agents affect their mechanical and aesthetic properties. Fungi — which are classified as staining, molding and rotting — are one of the main responsible for the biggest losses in the timber industry. Wood can be virtually used in a whole range of environments, a fact that makes it susceptible to attacks by different fungal species, since the ideal conditions for fungal development change from species to species. In other words, the fact that one or more fungal species are capable of deteriorating wood is directly related to conditions wood is subjected to. Thus, it is essential knowing how to evaluate fungal attacks, symptoms to be taken into consideration at the time to identify the type of attacking organism and the attack stage, as well as the control and prevention measures to be applied to these organisms.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.