Cells of each filament put out a conjugation tube




Дата канвертавання26.04.2016
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Spirogyra 2

Conjugation
At certain times of the year, tubular structures grow out from each cell of a pair of filaments lying parallel to each other. The tubes join up to make a passage between each cell and its partner.

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Cells of each filament put out a conjugation tube

The conjugation tubes meet and join up. The chloroplast starts to break down. The cell contents become a gamete.

The cell contents of one filament pass through the conjugation tube and the nuclei fuse.

Although there is no visible difference between the filaments, one is clearly acting as the producer of ‘male’ gametes.





The zygote forms a wall round itself and becomes a spore which can resist

adverse conditions, e.g. cold and lack of light.



When conditions improve, the spore germinates to produce a new filament

© D.G. Mackean

spore

cell wall breaks down
he chloroplasts and other structures become less distinct and the cytoplasm pulls free from the cell wall to form a rounded structure. The cytoplasmic contents of the cells of one filament then pass through the tube (conjugation tube) and fuse with the cytoplasm of the cells of the adjacent filament.


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