Question

In which of the following placentation, ovules are borne on central axis and septa are absent?

• A. Marginal
• B. Free central
• C. Parietal
• D. Axile

Answer 1

The correct option is B Free central

The arrangement of ovules within the ovary is known as placentation. The placentation are of different types namely, marginal, axile, parietal, basal, central and free central.

• When the ovules are borne on central axis and septa are absent, as in Dianthus and Primrose the placentation is called free central.
• In marginal placentation the placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows, as in pea.
• When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentation is said to be axile, as in China rose, tomato and lemon.
• In parietal placentation, the ovules develop on the inner wall of the ovary or on peripheral part e.g., mustard and argemone.
• In basal placentation, the placenta develops at the base of ovary and a single ovule is attached to it, as in sunflower, marigold.