Life cycle oedogonuim Oedogonium is a genus of filamentous green algae , with unbranched filaments that are one cell thick...
Life cycle
oedogonuim
Oedogonium is a genus of filamentous green algae, with unbranched filaments that are one cell thick. Oedogonium can be free-floating, though it is usually attached to aquatic plants by a holdfast.[1] It appears greenish and inhabits calm, fresh water.
Asexual reproduction
Oedogonium can reproduce
asexually by fragmentation of the filaments, through some other types of
non-motile spores, and also through
zoospores, which have many flagella. These develop in a
zoosporangium cell, one zoospore per zoosporangium. After settling and losing
its flagella, a zoospore grows into a filament
Sexual reproduction
The life cycle of Oedogonium is haplontic, i.e., meiosis is
zygotic. Antheridia which produce sperm,
and oogonia which produce an egg,
release the sperm and egg. The egg and sperm then fuse and form a zygote which is diploid (2n). The zygote then
produces the filamentous green alga which ishaploid (1n).
Species
Species of Oedogonium are divided into two
major groups on the basis of the distribution of the sex organs:
·
Macrandous Species – In these species,
antheridia are borne on filaments of normal size. This group is further
subdivided into:
·
Macrandous Monoecious – In these species,
antheridia and oogonia are found on the same filament. Eg: O. nodulosum and O.
fragile
·
Macrandous Dioecious – In these species,
antheridia and oogonia are borne on different filaments. Although filaments
bearing antheridia and oogonia are morphologically similar, they differ
physiologically. Eg: O.
crassum and O. aquaticum
·
Nannandrous Species – In nannandrous
species, filaments bearing antheridia and oogonia show morphological
distinction. The male filament, which are much smaller than the female
filament, is called a dwarf male or nannandrium. Nannandrous species are always
dioecious, i.e., antheridia and oogonia are borne on different filaments. The
small male filaments are likely to be attached to a female filament, near an
oogonium
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