Reaction of Japanese Larch Inoculated with Ceratocystis piceae

1991

6 Abb., 1 Tab., 6 Lit. Ang.

Unselbständiges Werk

4590

200048415

The reaction of Japanese larch trees incoculated with Ceratocystis piceae was investigated for a clear explanation of wilt occuring on Japanese larch which were attacked by Ips cembrae. The lesion area on the inner bark of the inoculated trees was larger than that in the controlled trees. Surrounding the inoculation point, blue-stained wood and dry wood existed in the sapwood. Formation of the wound periderm and traumatic resin canal were not clearly indicated under microscopy observation. But, the ray parenchyma cells were necrotic in the blue-stained and dry sapwood near the inoculation point. We observed that unknown substances were attached to the inner wall of the tracheid and bordered pit-pairs under scanning electric microscopy (SEM) observation. Many aspirated bordered pits were also observed in the blue-stain wood and dry wood. It seemed that the aspirated bordered pits prevented the invasion of hyphae to the adjacent tracheid in the sapwood. But in some cases, the hyphae of C. piceae penetrated the torus of aspirated bordered pits. These results suggested that C. piceae was directly associated with the wilt of japanese larch which were attacked by I. cembrae.