Influência do teor de extrativos na arquitetura hidráulica em espécies florestais da Amazônia Central

Abstract

The objective of this research was to study the influence of the extractives content in the hydraulic architecture and in anatomical properties to understand the interaction of these variables in the transport of water in the trunk. The samples were collected in a managed forest area of the company Precious Woods, where disks were collected from the base and apex of 13 trees. The tree species collected were separated into two density groups (Db): medium (0.52–0.71 g / cm³) and high (0.75-0.94g / cm³), the density values were obtained in three radial positions 0%, 50% and 100%. The variation in the basic density tends to increase in the 50% position (intermediate region between heartwood and sapwood) and then decreases, obtaining the lowest values for the 100% position (sapwood), the variation in the longitudinal direction is very likely to be different, with lower values at the apex. The content of aqueous extracts (Te%) was obtained by the hot water extraction method with an adaptation of the ASTM D-1110/84 standard. The results of Te% showed average values for heartwood of 10.64% and sapwood 10.09%, and the variation in the extract content was from 6.81% to 14.79%. The highest values of t and% were found in the sapwood corresponding to hydrophilic organic substances such as starch and sugars present in the parenchyma cells. High density species showed the highest values of Te% at the heart. The coloring of the aqueous extract of the high density species showed a darker color than the extract of the medium density species. The hydraulic conductivity (Ks) was obtained from the values of diameter (Dv) and frequency (Vd) of vessels, and was higher in individuals of medium density. The analysis of the main components proved the trade-off between resistance and efficiency of hydraulic transport and the interaction of the extractives content with the hydraulic architecture.