Canadian Journal of Botany - Revue Canadienne de Botanique (1994) 72, 1164-1170

Theresa A.S. Aveling, Heidi G. Snyman and F.H.J. Rijkenberg (1994)
Morphology of infection of onion leaves by Alternaria porri
Canadian Journal of Botany - Revue Canadienne de Botanique 72 (8), 1164-1170
Abstract: Conidial germination of Alternaria porri, formation of prepenetration structures, penetration of the onion leaf surface, and the postpenetration processes were studied using light, scanning electron, and transmission electron microscopy. Ninety-six percent of conidia germinated at 25 °C within 24 h of inoculation. Each conidium formed several germ tubes that grew in any direction across the leaf surface. Each germ tube usually terminated in a bulbous appressorium formed directly on the epidermal cell (52.4% of appressoria) or on a stoma (48.6% of appressoria). Following direct penetration of the outer epidermal cell wall or the stoma, bulbous primary hyphae developed below the appressoria. Secondary hyphae developed from the primary hyphae within 48 h after inoculation and grew within the intercellular spaces penetrating mesophyll cells. The changes in ultrastructure of cells in close proximity to hyphae and of infected cells are described.
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Link to article at publishers website
Database assignments for author(s): Theresa A.S. Aveling

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Alternaria porri	Onion/garlic/leek (Allium)