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Life Cycle of Mycosphaerella brassicicola (Duby) Lindau and Ascospore Production in vitro
Author(s) -
Götz M.,
Zornbach W.,
Boyle C.
Publication year - 1993
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1993.tb01431.x
Subject(s) - biology , ascospore , incubation , spore , ascocarp , mycelium , botany , primordium , horticulture , incubation period , hypha , sclerotium , inoculation , germination , desiccation , taxonomy (biology) , biochemistry , gene
The germ‐hyphae of the M. brassicicola ascospores penetrated the host leaves (white cabbage) 10 days after inoculation during the summer at 17 °C. The penetration occurred without exception by way of the stomata. Following a period of intercellular growth which lasted up to 15 days, brownish discolourations of the host cell walls and the destruction of mesophyll cells were observed. At this stage of infection, fruit‐body primordia developed from hyaline, thick‐walled, granulated mycelium, which blackend after conglomeration due to melanine deposits. The further ascocarp development was ascolocular. Ascospore production of M. brassicicola was increased in vitro by variation of the incubation temperatures, medium‐pH and irradiation. The highest sporulation rate was obtained in cultures on vegetable juice medium adjusted to pH 6, incubated at 17 °C and subjected immediately after onset of growth to 4 h UVA radiation. The percentage of germinated ascospores (70 %) corresponded to that of the dark incubated controls. Fructification and infectivity were subject to seasonal fluctuations under growth chamber conditions.