Abstract:

The present study, based on the results of inoculation of Leptogramphium yunnanense associated with Tomicus piniperda on Pinus yunnanensis trees, made histological observations on the pine tree tissue infected by the fungi. The study demonstrated the pathogenic function of the fungi. The fungi were found in various types of the cells of the infested phloem and sapwood. In wood section the blue stained area appeared in the sapwood as the fan around the heartwood. Inside phloem tissue, the fungi mostly extended along various cell axes in vertical, and horizontally entered the adjacent cells through cell pets. The rule of the fungi distribution and growth inside the phloem and sapwood of the host trees were illuminated in this paper, and it so further proved that L. yunnanense is one type of pathogenicity fungi on Yunnan pine trees at some degrees.

Key words: Tomicus piniperda, Blue stain fungi, Pinus yunnanensis, Wood anatomy