. Discuss zygospores and its Germination


Best Answer

ZYGOSPORES

The mature zygospores have a three layered wall; the outer smooth thin and cuticularized exosporium. The middle brown thick and ornamented mesosporium, and the inner thin endosporium. The mesosporium is made up of chitin while the remaining two are made up of cellulose. The mesosporium serves as a main distinguishing character for different species of Spirogyra.

GERMINATION OF ZYGOSPORE

Zygospore germinates after the onset of rains. During germination the diploid nucleus of the zygospore divides meiotically. As a result four haploid nuclei are formed. Of these, three degenerate and the remaining one enlarges. Meanwhile the two outer layers of the zygospore burst open and the endosporium comes out in the form of a cylindrical germ tube. Later, the germ tube divides transversely forming a two celled filament. The distal (upper) cell, by repeated transverse divisions, forms a long multicellular uniseriate filament. Thus in Spirogyra each zygospore on germination gives rise to a single filament.

 

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