Histopathology of Carnation Infected with Fusarium oxysporum f. sp. dianthi

Colonization and histopathology of susceptible and resistant carnation cultivars infected with Fusarium oxysporum f. sp. dianthi

“…Gels would limit fungal spread by occluding the vessels. The present report confirms that, in carnation, abundant gelation is characteristic of Fusarium wilt-resistant interactions, as reported previously (Harling and Taylor, 1985;Pennypacker and Nelson, 1972). However, vascular occlusion by gels has been shown to be one of the main causes of wilt symptoms in several other plant-pathogen interactions, e.g.…”

“…Anatomical differences found in this study that possibly allow for resistance are alterations of primary cell walls, gel formation in vessels, and hyperplasia of xylem parenchyma followed by xylem regeneration. Discoloured and thickened primary walls have been reported to occur after inoculation of carnation (Pennypacker and Nelson, 1972;P6resse, 1975), chrysanthemum (Emberger and Nelson, 1981;Stuehling and Nelson, 1981), and tomato (Chambers and Corden, 1963) and are interpreted as deposition of material formed by infected cells or by accumulation of products of nearby disintegrating cells. Other possible explanations for the thickening of walls are cell wall swelling or lysis induced by the pathogen.…”

“…Vascular gelation has often been reported for carnations infected with various pathogens (Catesson et al, 1976;Harling and Taylor, 1985;Pennypacker and Nelson, 1972;P6resse, 1975). The histochemical tests used indicated that these gels are composed of various amounts of polysaccharides, among which are pectin and probably hemicellulose, together with oxidized polyphenols, all of which are considered to be normal gel components (Beckman and Talboys, 1981).…”

“…dianthi, the resulting tension forces sometimes causing stem bursts (Harling et al, 1984;Harling and Taylor, 1985;Pennypacker and Nelson, 1972;P6resse, 1975). Hyperplasia and hypertrophy were not observed in susceptible 'Early Sam' contrary to previous reports for susceptible carnations (Pennypacker and Nelson, 1972;Harling and Taylor, 1985).…”

“…dianthi, the resulting tension forces sometimes causing stem bursts (Harling et al, 1984;Harling and Taylor, 1985;Pennypacker and Nelson, 1972;P6resse, 1975). Hyperplasia and hypertrophy were not observed in susceptible 'Early Sam' contrary to previous reports for susceptible carnations (Pennypacker and Nelson, 1972;Harling and Taylor, 1985). Pennypacker and Nelson (1972) observed that hyperplastic xylem parenchyma cells were arranged in orderly columns with a less virulent Fusarium isolate only, closely resembling the situation in 'Novada' and 'Carrier 929' (Harling and Taylor, 1985).…”