Question

Two adjacent filaments of Spirogyra affinis having 10 cells each are participating in reproduction. How many new Spirogyra plants are produced during sexual reproduction?

• A. 5
• B. 10
• C. 20
• D. 40

Answer 1

The correct option is B 10

In sexual reproduction there are two types. One of them is scalariform conjugation. That is when two different filaments are needed and they have to line side by side. Next, one of the cells gives tubular protuberances. Tubular is something in shape of a tube. This is known as conjugation canals. After this tubes are connected , they transport the cytoplasms. The second type of sexual reproduction is lateral reproduction. The cells of adjacent filaments develop bumps which grow towards one another and eventually fuse to form a continuous tube between the cells and this is called conjugation tubes. They also make conjugation canals.Meanwhile the contents of each cell have detached themselves from their respective cell walls and have formed a round ball. Over a relatively short space of time (minutes), the green spheres from the male filament squeeze their way down the connecting tubes to fuse with a similarly contracted female cell in the other filament. The result of this sexual union is the formation of a zygospore with a tough resistant outer covering within the chambers of the female filament. After a dormant period, these zygotes undergo meiosis and germinate, resulting in new filaments of Spirogyra.