Heartwood stain in red oak

摘要: The paper describes the appearance, properties, and ultrastructure of red oak heartwood containing dark discolorations. possible cause origin discoloration are discussed, although etiology stain is not explicit. It was found that moves from ray parenchyma to adjoining vessels, fibers, tracheids by pit membranes plasmodesmata. appears there may be extended openings in membrane which facilitate movement materials through such a specialized filamentous structure. Internal checking or honeycomb as an indirect result discoloring material mentioned.