Question

What happens when a mature spirogyra filament attains considerable length?

Answer 1

When a filament of mature Spirogyra attains considerable length, it breaks into several fragments which grow into new individuals.

Answer 2

spirogyra reproduces asexually through fragmentation. In this reproductive process, after attaining considerable length (maturation), the Spirogyra breaks down into fragments and consequently, each fragment gives rise to a new Spirogyra.