Investigations of Verticillium dahliae pathogenesis in Impatiens balsamina and Brassica napus
1991
Niederleitner, S. (Technische Univ. Muenchen (Germany). Lehrstuhl fuer Phytopathologie und Lehrstuhl fuer Physik) | Zinkernagel, V. | Bartscherer, H.-C.
Impatiens balsamina und Brassica napus were inoculated with Verticillium dahliae. A few weeks after inoculation, Impatiens plants showed severe symptoms of wilt, a similar wilt did not occur in rape, with the exception of some unspecific chlorosis of older leaves. The fungus could always be isolated again from Impatiens, however, only occasionally from rape. It could nevertheless be demontrated in both hosts by using transmission and scanning electron microscopy. Occlusion of xylem vessels by numerous hyphae, tyloses and vesicular material is due to tracheomycotic activity. In later stages of pathogenesis, vessels of both Impatiens and rape were covered with coating material, more or less distinct. Impatiens hyphae had this material as well. An efficient coating may restrict lateral penetration of the fungus, supposing it is build up completely in due time. Degenerated membranes, cell walls and organells in xylem vessles and in parenchyma cells indicate toxic and enzymatic activities by the fungus
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