OEDOGONIUM The filament is attached with the help of colourless disc like hold fast to the substratum. Plant body is of filamentous, unbranched. It is aquatic found in permanent, semipermanent fresh water of pools, tanks ditches etc. Presence of large single nucleus and a reteculate chloroplast with numerous pirenoids. Presence of caps in the dividing cells. The cell wall with outer chitin, middle pectin and inner cellulose.
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OEDOGONIUM The filament is attached with the help of
colourless disc like hold fast to the substratum. Plant body is of filamentous, unbranched. It is aquatic found in permanent,
semipermanent fresh water of pools, tanks ditches etc.
Presence of large single nucleus and a reteculate chloroplast with numerous pirenoids.
Presence of caps in the dividing cells. The cell wall with outer chitin, middle pectin
and inner cellulose.
REPRODUCTION 1.Vegetative 2.Asexual 3.Sexual types
VEGETATIVE REPRODUCTION 1.Fragmantation—by accidental
breaking of filaments into small pieces– each of which develop into a new filament.
2.ASEXUAL REPRODUCTION 1.By multi flagellate zoospores. Any vegetative cell except hold fast and
apical cell may function as zoosporangium and form single zoospore.
In each zoospore flagella are arranged in a ring like around a colourless beak like area.
2. By Akinetes------- In unfavourable conditions thick walled akinetes are formed in chains of 10-40 in vegetative cells with reserve food starch and oil. They germinate on favourable conditions and give rise to new oedogonium filaments.
SEXUAL REPRODUCTION Oogamous type Female sex organ Oogonium and male
sex organ antheridium. Oedogonium may be homothallic or
heterothallic Antheridia may develop in macrandrous
type or nonnandrous type.
SEXUAL REPRODUCTION In macrandrous male sps antheridia are
produced in rows on normal sized filaments but in nonnandrous sps the antheridia are produced on special dwarf male filaments. The dwarf male filamens are produced by the germination of multiflagellate androspore.
MACRANDROUS MALE Any vegetative cell vegetative cell
except holdfast cell may act as antheridial mother cell.
It divides and redivides to form a row of 8-40 antheridia.
The protoplast in each antheridium may produce single or two antherozoids or spermatozoids.
The antherozoid is like zoospore, but small in size poorer in chlorophyll and fewer flagella
NONNANDROUS MALE Dwarf males or nonnandria are special dwarf filaments on which antheridia are born.
The dwarf males attach themselves to the filament bearing oogonium.
The dwarf males are produced by the germination of special types of zoospores, called androspores that are formed singly within the androsporangium.
Androsporangium is quite similar in appearance to the antheridia of macrandrous male spsnand they are developed in a row from the vegetative cells in the same manner as that of the antheridia of macrandrous malesps. Each androsporangium produce single androspore.
Androspore is intermediate in size between zoospore and antherozoid.
Androspore attach to the wall of the oogonium and germinates and form dwarf males.
In nonnandrous sps both antheridia and oogonia are on the same filament hence the sps is termed as Gynandrosporous, if they are produced on different filaments they are termed as idioandrosporous
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