Caracterização da lignina da raque de Couroupita guianensis Aubl. por técnicas de micro análise

Abstract

The purpose of this dissertation was to study by the micro analysis the rachis lignification of Couroupita guianensis (Lecitidaceae family, originally from the Amazon) considering the influence of gravity on the formation of special tissues in order that the rachis has a positive growth with respect to the gravitational force. The experiment was conducted at the Laboratory of Wood Chemistry, where the rachis was dried, prepared to cutting anatomical and chemical analysis. Histochemical tests were analyzed by optical microscope images of tissue of the rachis, with microspectroscopy and infrared spectroscopy-FTIR. The tissue of the rachis presented features of tissue tension, with gelatinous fibers, as evidenced by the Wiesner test and the reaction Lawrens-Takaashi (zinc chloride iodate). Histochemical tests were efficient and showed that in regions of high flexibility has syringyl lignin. The micro spectrometric spectra showed the existence of lignin, but not enough to affirm the predominant type of lignin in a given region of tissue. The tissues were extracted with NaOH 1% and acetone, however, the infrared spectra of the cross sections pre-extracted with acetone, allowed to identify characteristic signs of guaiacyl and syringyl. Spectra of the milled material only extracted with organic solvents (cyclohexane, ethyl acetate ethyl and methanol) or with 1% NaOH for 1 hour confirmed that lignins are guaiacyl and syringyl type.