The effect of woody and non woody plants extractives on microbial resistance of non-durable species
S M Kazemi, A Hosinzadeh, M B Rezaii
The effect of Elm (Zelkova carpinifolia), Oak (Quercus castanifolia), Mulberry (Morus alba), Ash (Fraxinus excelsior) as woody plants, Rose (Rosa damascene) and Fumitory (Fumaria sp) as non woody plants extractives on durability of Beech (Fagus orientalis), Maple (Acer insgin), Alder (Alnus subcordata), and Lime (Tilia sp) were studied. First wood species having extractives were cut to small pieces and then were chipped and milled, by using Tappi (T20403-76) standard. Acetone and Methanol solvents were used to extract soluble materials from wood durable species, and their extractives percentage were measured. Also wood specimens of perishable species such as beech measuring 0.5 x 1 x 5 cm were prepared. The fungus (Trametes versicolor) was selected and taken from the forest (Darabkola in Mazandaran state). Solvated extractives were injected into non-durable wood species by negative atmospheric pressure and then treated wood specimens oven dried at 50 o C. Then all treated and untreated wood blocks again oven dried, cooled, sterilized, and exposed to the fungus. Milled wood (with and without extractives) as control specimens were poured into Pyrex tube glasses, oven dried, cooled, weighed, sterilized and also exposed to the fungal attacks. At the end of experiment (after 6 weeks) mycelium were removed from surfaces of exposed wood samples and wood blocks oven dried, cooled, and weighed. Results showed that weight losses of all treated wood species except Lime significantly decreased. Other results indicated that Alder and Lime absorbed solvent more than Beech and Maple. However, solvated extractive of Mulberry significantly was inserted less than other wood extractives.