Question

Zygospore of Spirogyra produces

• A. 2 zoospores
• B. 4 zoospores
• C. 2- 4 zoospores
• D. None of the above

Answer 1

Answer: (D)

None of the above

Zygospore is the only diploid phase in the sexual life cycle of Spirogyra. The decay of female gametangia causes the liberation of zygospore which remains dormant in the pond bottom till the favorable conditions return.

On return of favourable condition the diploid nucleus of zygospore undergo meiosis to produce 4 haploid nuclei out of which 3 degenerate. The zygospore with one haploid nucleus gradually enlarges and burst open to release a germ tube. The repeated transverse divisions of germ tube form a new filament.