DETECTION OF ORTHO-QUINONES IN WOOD USING CONFOCAL LASER-SCANNING MICROSCOPY

Confocal laser scanning microscopy (CLSM) was used to determine the sp atial distribution of ortho-quinones in unbleached black spruce and ja ck pine, and hydrogen-peroxide-bleached black spruce wood. Both sapwoo d and heartwood sections were examined. Wood was treated with ortho-ph enylenediamine to react with ortho-quinones to give fluorescent phenaz ines. The CLSM images of labelled samples were obtained at 568 nm wave length, at which autofluorescence due to other chromophores in wood is negligible. Ortho-quinones are found in highest concentration in the torus, middle lamella, cell comers and ray cells, and in lesser concen tration in the cell wall. In hydrogen-peroxide-bleached wood ortho-qui nones are not as concentrated as in unbleached wood.