ULTRASTRUCTURAL-CHANGES DURING WOOD DECAY BY ANTRODIELLA SP RK1

Southern yellow pine (softwood) and maple (hardwood) wood decayed for 12 weeks by Antrodiella sp. RK1 had average weight losses of 20 and 19 %, respectively, and approximately 34 to 35% lignin loss. The ratio of percentage lignin loss to glucose loss was 3.6 and 2.7 for softwood a nd hardwood, respectively. There was negligible loss of other wood sug ars such as xylose, arabinose, galactose and mannose. Scanning electro n microscopy revealed the presence of erosion troughs and bore holes i n decayed samples of both softwood and hardwood. Secondary walls were void of lignin, middle lamella and cell corners were extensively decay ed. Ca2+ crystals were abundantly present in the areas of decay. Trans mission electron micrographs revealed the presence of hyphal sheath an d growth of hyphae directly through the cell corners.