How does spirogyra reproduce sexually?

Sexual reproduction of Spirogyra is called conjugation. When conjugated in the process of fusion of two cells of separate individuals of spirogyra, a zygote is formed. Further, a thick shell is formed in the zygote, at that moment transformation into a zygospore occurs. As such, she experiences adverse conditions. After meiotic division, the zygospore “gives” four spores. One of the spores grows into a young Spirogyra. All stages, except for the stages of the zygote and zygospore, are haploid, but the zygote and zygospore are diploid.