Variação Estrutural Quantitativa do lenho de Inga Subsericantha Ducke (leg. Mimosoideae)

Abstract

The physical and mechanical characteristics of wood reflect significantly in the process of technological transformation of this raw material into manufactured products. Due to the heterogeneity of wood, anatomical characteristics may vary in samples taken from the same trunk in regions distant from each other. Several studies related to the variation patterns caused by these processes have shown different variation models, but sometimes no defined pattern of variation is established. The knowledge of the anatomical characteristics of the lnga subsericantha Ducke wood may favor its processing and, at the same time, may contribute to the scientific knowledge of the species, since anatomical studies at the microscopic level of tropical species are still scarce. For the present study, wood discs were removed along the stem, from which test bodies were obtained every 2 cm, in the medulla-exchange direction. For a quantitative analysis of the wood, temporary slides were prepared to measure the length, wall thickness and diameter of the fiber lumen; the tangential diameter, length and frequency per mm/ of the vessels; the height (in micrometers and number of cells), width (in micrometers and number of cells) and frequency of the rays. Through the results it could be observed that the diameter, height and frequency of the vessels showed an increase towards the cambium. Small oscillations of the values occurred both in the axial and radial direction. Regarding the fiber parameter, the values showed great variation in the radial and axial direction, with a tendency to increase towards the cambium, except for the thickness of the lumen. Among the characters related to the rays, the width was the one that showed the most stable values, increasing towards the cambium. For height and frequency of the rays (in micrometers and in number of cells), there were several oscillations towards the cambium. Regarding the axial direction, the variability of the values referring to the radius was not high. The factors responsible for the quantitative variations occurring in the xylematic elements may be due to silvicultural, environmental and/or genetic characteristics. Such factors have different influences among species and within the same tree.