Potencialidade dos extratos de Hovenia dulcis e Ateleia glazioviana como biopreservantes de madeiras

Abstract

The present study aims to obtain and test in the laboratory the aqueous extracts of the lignocellulosic materials (bark, wood and leaves) of the tree species of Ateleia glazioviana and Hovenia dulcis as biopreservantes of wood. For this, five trees of each species were cut, and the vegetal materials were obtained for the preparation of the aqueous extracts. These were incorporated into the culture medium in petri dishes in order to verify the toxicity to the main deteriorating fungi of the wood: Pycnoporus sanguineus and Gloeophyllum trabeum. Experiment evaluations were initiated 24 hours after inoculation by daily measurements of mycelial growth until the control plaques were taken up by the fungi. The extracts were also tested as bioinsecticides in the control of termites. For this purpose, filter papers impregnated with extracts were placed in petri dishes and after 20 active termites were added to each plate, which were incubated at 28 ± 2 ° C, 75 ± 5 % of temperature and relative humidity of air, respectively. In each plate the percentage of termite mortality was calculated for 2h and 24h. In addition, 2,54 x 2,00 x 1,00 cm (fungi) and 2.54 x 2,00 x 0,64 cm (termites) test specimens will be made for accelerated biodeterioration tests in the laboratory against the fungus Trametes versicolor and samples of 2.00 x 2.00 x 30.00cm for field testing in a forest environment. The samples for the laboratory and field tests were treated with the extracts in a laboratory autoclave using the empty cell method, using lower (untreated samples) and upper controls (treated with a Chromed Copper Borate-CCB mixture). The evaluations of the test in the laboratory were made by measuring the loss of mass of the samples, scanning electronic spectroscopy (SEM), solubility in NaOH 1% and spectroscopy in the infrared by attenuated total reflectance (ATR-IR). For the field trial in a forest environment, mass loss, infrared spectroscopy by attenuated total reflectance (ATR-IR) and dynamic flexion were evaluated. All aqueous extracts of Hovenia dulcis and Ateleia glazioviana have fungitoxic potential against fungi representing white and brown rot and insecticidal potential against termites. In general, extracts from Ateleia glazioviana proved to perform better than those from Hovenia dulcis, and may be used in the future as wood biopreservers.