Question

Parietal placentation is characteristic of
A) Brassica campestris
B) Hibiscus rosa sinensis
C) Allium cepa
D) Solanum nigrum

Answer 1

Hint:When ovules develop on the wall or slight outgrowth of the wall forming broken partitions within a compound ovary such of your placentation is known as parietal placentation.

Complete answer:
The ovule is attached to the ovary wall until maturity by a short stalk called funiculus . The area of attachment to the ovary wall is referred to as placenta. The arrangement of placentae that is present in the compound ovary of angiosperms is characterized by the presence or absence of a central column in the ovary and by the site of attachment. There are different types of presentation as marginal, exile, parietal, basil, central and free central.

Hibiscus rosa-sinensis belongs to the family Malvaceae. It shows axile placentation. In axile placentation, the placenta is axial and ovules are attached to it in a multilocular way.

Allium cepa (onion) belongs to the family Liliaceae. It has axile placentation.

Solanum nigrum belongs to the family Solanaceae. It has swollen placenta to which many ovules are attached i.e., axile placentation.

Brassica campestris (mustard) belongs to the family Brassicaceae. It shows parietal placentation. In parietal placentation, ovules develop on the inner wall of the ovary or on the parietal part.

Thus, the correct answer is option A.

Note:Features of gynoecium Brassicaceae family are as follows : usually bicarpellary rarely tricarpellary, syncarpous, ovary superior , unilocular becomes bilocular due to the development of false septum called replum. Parietal placentation , many ovules, short style and stigma are simple or bifid. The crucifer carpel has been a puzzling subject for the morphologists and the attention attracted towards it for a long time.