When does reduction division occur In Ulothrix?

Hint: Meiosis is also known as "reduced division" because it reduces the amount of chromosomes to half the usual number so that the infant has the correct number when sperm and egg fuse. A diploid body cell in this case has 2n = 4 chromosomes, two from mom and two from dad.

Complete answer:
Ulothrix is a genus of non-branching filamentous green algae.
Meiosis, or reduced division, occurs in Ulothrix at the period of zygospore development. Ulothrix has a haploid plant body (gametophytic). It produces zoo gametes (n), which unite to form a resting spore called a zygospore (2n) diploid.
When the conditions are favourable, the zygospore undergoes meiosis, or reductional division, which results in the formation of zoo­meiospores. At the period of zygospore production in Ulothrix/ Spirogyra, reduced division (meiosis) occurs. Ulothrix and Spirogyra create zoogametes (n) that unite to make zygosporic (2n) diploid, which is a resting spore, and their plant bodies are gametophytic (haploid).
Reduction division occurs in the anthers of the stamen (generating haploid pollen grains) and the ovary of the pistil (creating haploid pollen grains) (producing eggs). Ulothrix is a genus of green algae that belongs to the Ulotrichaceae family. Ulothrix is a non-branching filamentous green algae genus that can be found in both fresh and saltwater. Its cells are generally as wide as they are long, and it thrives in the colder months of the year.

Note:-
Its cells are generally as wide as they are long, and it thrives in the colder months of the year. A redesigned holdfast cell helps them stick to surfaces. Vegetative reproduction is the norm. They are unicellular and eukaryotic.Ulothrix, a genus of filamentous green algae (family-Ulotrichaceae) found in marine and fresh waters.