Morphological Characteristic of the Rust Fungi, Uromyces truncicola, and Histological Changes in the Infected Host Tree, Sophora japonica

摘要

The rust fungus, Uromyces truncicola, infected stems, branches and leaves of Sophora japonica trees, and 78% of planted host depending on investigated sites. Teliospores of this fungus were reddish brown, global to oval and 29-37x24-27 mu m. The urediniospores were yellowish brown, elliptical to oval with spiny surface and 28-39x19-22 urn. In the infected branches cork layers were thickened, ray parenchymatous cells were distorted, branched or combined and increased in numbers. While ray parenchymatous cells in healthy branches were one or two layers, the cells in the infected branches were three or more layers to shape fusiform. In the infected branches xylem tissues also distorted and yellowish pigments formed in the intercellular space. In the less infected trees the hairs on the branches were dense and long, and the thickness of upper epidermal cell walls were ca 23.3 mu m, while in the highly infected trees the hairs were less dense and short, and the thickness of upper epidermal cell walls was ca 17.4 mu m. We think individual host trees resistant to this fungus are present.