Latent Infections by Fungi

摘要: Before a pathogenic fungus establishes parasitic relationship with its host plant, number of stages in the life cycle will have been passed. After spores land on surface host, germination takes place if circumstances are favor­ able. A spore can germinate immediately after landing, or it take some time before occurs. During this time, must remain viable; be isolated by washing from and plating out suspension or, when stuck to surface, pieces tissue. This period between landing is sometimes referred as latent infection, although no infection has yet taken place. occurred, germ tube penetrate directly into tissue, without development superficial mycelium preceding penetration. In both cases, hyphae produced appressoria. Som!!times these appressoria viable for but not Penetration occurs various ways. many an hypha penetrates cuticle then outer epidermal cell wall. start relationship. However, may pass penetration such stage correctly latent, dormant, quiescent infection. The actual place, though macroscopically visible, further growth delayed. Nothing known about parasite at stage; there might equilibrium two. implies that term latency should described dormant rc;:lationship which, change active one. definition given above, first stated Giiumann (32), used paper, I do extend definition, did, those Usti/ago spp. during which external