Final answer:
Conjugation in Spirogyra is a sexual reproduction process where two filaments of opposite mating types form conjugation tubes, allowing nuclei to migrate and fuse into a zygospore.
Step-by-step explanation:
Conjugation in Spirogyra
Conjugation in Spirogyra, a genus of algae, is a form of sexual reproduction. It takes place under unfavorable environmental conditions where two filaments of opposite mating types (often referred to as "+" and "-") align side by side.
The process begins with the formation of outgrowths called conjugation tubes between cells from opposite strands.
The contents of one cell, which include the haploid nucleus, then migrate through the tube into the adjacent cell of the other filament. This migration leads to the fusion of haploid nuclei, forming a diploid zygote known as a zygospore.
The zygospore has a thick coat, which provides protection against desiccation and other hazards, allowing it to remain dormant until conditions improve.
Once favorable conditions return, the zygospore germinates, undergoing meiosis to produce haploid spores. These spores then grow into new algal filaments, completing the cycle and ensuring the survival of the species.