Variação anatômica no lenho de Astronium lecointei Ducke

Abstract

RESUMOCom o objetivo de avaliar a variação dos elementos celulares de Astronium lecointei Ducke no sentido medula-câmbio, analisaram-se amostras de madeira de três regiões radiais da árvore, a 1,30 m do solo: 0% (próximo à medula), 50% (região intermediária) e 100% (próximo ao câmbio vascular). A metodologia aplicada no trabalho foi aquela tradicionalmente recomendada para estudos em anatomia de madeira, seguindo orientação do IAWA Committee. Observou-se que alguns elementos anatômicos apresentaram tendências de variação definidas e estatisticamente significativas: frequência, diâmetro e comprimento dos elementos de vaso, altura dos raios em micrômetros e comprimento das fibras. Observou-se também maior obstrução dos poros por tilas próximo à medula e na região intermediária. A tendência de estabilização das dimensões dessas estruturas pode estar indicando a formação de madeira adulta a partir da região intermediária analisada no lenho da espécie. Palavras-chave:Astronium lecointei, elementos celulares da madeira, variação radial. ABSTRACTIn order to evaluate the variation of the cellular elements of Astronium lecointei Ducke from the pith towards the vascular cambium, wood samples from three regions of the radial sense in the tree at 1.30 m above the groundwere analyzed: 0% (near to the pith), 50% (intermediate region) and 100% (near to the vascular cambium). The methodology applied in the work was the one traditionally recommended for studies in wood anatomy, following the guidance of the IAWA Committee. It was possible to observe that some anatomical elements showed well-defined, statistically significant variation trends: frequency, diameter and length of the vessel elements, length of rays in microns, and fiber length. There was also greater pore blockage by tyloses close to the pith and in the intermediate region. The tendency to stabilize the values of these structures may indicate the formation of adult wood as from the intermediate region analyzed in the wood of Astronium lecointei Ducke.

Physical and anatomical properties of Hevea brasiliensis clones

“…Narrower and fewer vessels are observed in the pith region, while wider and fewer vessels are found in the region close to the bark (Figures 1a and Figure 1b). The pattern of variation in cell dimensions was very similar to that found by Lima et al (2011) in Cariniana legalis and Melo et al (2013) in Astronium lecointei. To better explain the relationships among basic density, volumetric shrinkage and cell dimensions, relative to radial position, Pearson's correlation analyses were performed (Table 4).…”

“…However, this trend was not significant for ray width and ray frequency. This same trend also occurred in Astronium lecointei (Melo et al 2013).…”

Brazilian cerrado species: wood characteristics

“…The values of the vessel diameter indicated an increase in the pith-bark direction. This tendency was also verified by Dünisch et al (2004), Chagas et al (2007), Roque and Tomazello Filho (2009) and Melo et al (2013). Carlquist (1989) reports that the increase in vessel diameter in the radial direction (pith-bark) as a function of the tree'sage can be considered an anatomical adaptation of the xylem to increase the sap volume, and to consequently increase its photosynthetic capacity.…”

Experimental Investigation on the Variabilities of the Elastic Properties of Amazonian Hardwood Cordia Goeldiana

“…Such quality is defined according to type and purpose of the product and have been quantified by means modal parameters (natural frequencies, damping and quality factor), which determines tone, decay and volume of sound produced. In this context, two issues can be raised: on one hand, it is known that modal parameters are affected by elastic properties and density, and on the other hand, wood can present several patterns of variability in its properties (Cruz et al 2003, Valente et al 2013, Melo et al 2013, Araújo et al 2016. Taking this into account, it is relevant to consider how the natural variability, important for dynamic analysis of wood structures, interferes with sound response, especially for standardisation of musical instruments.…”