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twist together to form thick hyphal cord, called rhizomorph which bear the fruit bodies.
Agaricus
reproduces by all the three means: vegetative, asexual and sexual.
VEGETATIVE REPRODUCTION
It is mostly
propagated by vegetative means where dikaryotic mycelium develops spawn, the
mushroom seed. The mass spawn divides artificially into small blocks that are
grown in soil supplemented with organic manure to obtain fruits bodies.
SEXUAL REPRODUCTION
It takes place
by chlamydospores that are formed rarely during unfavorable condition. Terminal
or intercalary chlamydospores are developed on dikaryotic mycelium, which are
on germination during favorable condition produce dikaryotic mycelium.
Stages of plasmogamy |
SEXUAL REPRODUCTION
Sex organ are
absent in agaricus and sexual reproduction takes place by somatogamy. Most of
the species including agaricus campestries are heterothallic. Somatogamy in
includes plasmogamy, karyogamy, and meiosis. Karyogamy does not take place
immediately after plasmogamy, but meiosis follows soon after karyogamy:
- Plasmogamy: two cells of monokaryotic hyphae of opposite strains (- or +) come in contact with each other. The cell wall dissolve at the point of contact and a dikaryon (n+n) is formed this dikaryotic cell develops into dikaryotic mycelium by regular cell divisions through clamp connection. The dikaryotic mycelia are subterranean and after aggregation at some points they form botton which remains dormant before the rain comes during late summer. After rain, the soil become soft and the button develops into fruit body.
- Karyogamy: it takes place in the young basidium which develops in on gills in the fruit body. Both the nuclei fuse together and form diploid nucleus.
- Meiosis: it takes soon after karyogamy and forms four haploid nuclei. The basidiospore, thus formed on the sterigma of basidium are haploid and either of + or – type.
Growth of mycelium by clamp connection |
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