REPRODUCTION
Reproduction in fungi occurs by vegetative, asexual and
sexual methods.
Vegetative Reproduction
In this mode, a part or fragment of the somatic body
separates and forms a new individual. It occurs by
fission, budding, sclerotia and by
fragmentation,
rhizomorphs.
Asexual Reproduction
In asexual reproduction, a new individual is formed from a
specialised part of the parent. Gamete formation does not
occur. This commonly occurs through spores or small
single-celled or few celled propagules.
The asexual reproduction in fungi occurs by following
methods
(i) Zoospores In Phycomycetes, e.g., Albugo,
Saprolegnia, Achyla, etc.
(ii) Sporangiospores In Rhizopus, Mucor, etc.
(iii) Conidia In Penicillium.
(iv) Conidiosporangia In Phytophthora, Albugo.
(v) Chlamydospores In Rhizopus.
(vi) Arthospores In Mucor, Rhizopus.
Sexual Reproduction
All fungi reproduce asexually except the artificial group i.e.,
Fungi imperfecti (Deuteromycetes). The sex organs that
produce gametes
are called gametangia (sing.
gametangium). The sexual reproduction in fungi occurs by
oospores, ascospores and basidiospores.
The various spores produced in distinct structures are called
fruiting bodies.
The sexual cycle involves the following three stages
(i) Plasmogamy It is the first stage in which the
cytoplasm of two sex cells come close together but
do not fuse with each other. Only the protoplasm of
both cells fuse together. The resulting cell
is
dikaryon or binucleate. The phenomenon is called
dikaryotisation.
(ii) Karyogamy It is the stage in which two compatible
nuclei fuse together resulting into a diploid nucleus
is called synkaryon
(iii) Meiosis It is the stage in which the diploid nucleus
divides resulting in the formation of haploid nucleus
(reduction division).
There are various modes of sequal fusion in ferns. These are
as follows
(i) Plasmogametic copulation Fusion of motile
(flagellated) gametes takes place, e.g. Allomyces.
(ii) Gametangial contact The two gametangia are close
to each other but do not fuse. The non-motile male
gamete passes its nucleus into female gamete through
fertilisation tube, e.g. Phytophthora Albugo.
(iii) Gametangial copulation The two gametangia fuse to
form a zygospore e.g. Mucor, Rhizopus.
(iv) Spermatisation Numerous, minute, uninucleate
spore-like bodies, called spermatia, are transferred to
receptive hyphae cells e.g. Puccinia graminis.