Question

which helps spirogyra shows propagation ?

Answer 1

Vegetative reproduction happens through fragmentation of the filaments. Fragmentation happens in different ways. In case of mechanical injuries, the spirogyra filament breaks into fragments, and each fragment develops into a new filament. In some cases, the middle lamellae of the end walls of the cells dissolve, thereby causing breakage of the filament. This happens when the temperature and the pH of the water changes. It has also been observed that the lamellae of the end walls protrude inwards into the adjacent cells, thereby breaking the filament. The illustration given below shows fragmentation of a spirogyra filament as the end walls grow inwards, thereby causing fragmentation.