Cytopathological Responses of Picea abies Seedling Roots Challenged in vitro by a Necrotrophic Fusarium avenaceum (Fr.) Sacc.

Interaction of the necrotroph Fusarium avenaceum with seedling roots of Norway spruce was studied. The results showed that Norway spruce seedlings were susceptible to the pathogen but disease progression and severity was dependent on inoculum potential. Host recognition of the pathogen marked by hypersensitive browning reactions occurred late, thus making successful resistance to cellular damage impossible. Such host resistance responses were mostly in the form of ligniflcation, accumulation of electron dense materials and papillae formation