Question

In which of the conjugation types, involvement of two different filaments of Spirogyra is absent?

• A. Lateral
• B. Heterogenous
• C. Scalariform
• D. None of the above

Answer 1

The correct option is A Lateral

Sexual reproduction of Spirogyra involves conjugation, which may be defined as a primitive type of isogamy called aplanogametic isogamy. In this type of isogamy, the entire protoplasmic contents of vegetative cells (viz., gametangia) function as gametes. It always involves the gametangial contact. Conjugation is of two type—scalariform and lateral conjugation.

(i) Scalariform conjugation: It is the most common method in most heterothallic species of Spirogyra. Opposite cells develop outgrowths or protuberances called conjugation processes. At the point of contact, the tips of these processes dissolve (by cytase) to form conjugation tube between opposite cells.

(ii) Lateral conjugation: It is of rare occurrence and involves the fusion of gametes from two adjacent cells of the same filament in monoecious or homothallic species. It is of two types indirect and direct lateral conjugation.