Question

Parietal placentation occurs in the family
(a) Brassicaceae
(b) Asteraceae
(c) Solanaceae
(d) Liliaceae

Answer 1

The seeds of the plants of these families are used to extract mustard oil that is extensively used in cooking. After the extraction of oil, the cake left behind is used as cattle feed and fertilizer.

Correct step by step answer:
Placentation includes the arrangement of the ovules in the placenta followed by the arrangement of the placentas in the ovary of a plant. Parietal placentation occurs in the Brassicaceae family. In parietal placentation, the carpels are united by their adjacent margins and the ovules are disposed along the inner ovary walls.
- In the Brassicaceae family, plants are generally herbs, annuals, biennials, or shrubs. The taproots are present which are swollen due to food storage.
- The stem is woody, erect, and herbaceous. Leaves are alternate, opposite, and simple.
- The gynoecium is bicarpellary, syncarpous, superior ovary, due to the formation of a false septum, the unilocular becomes bilocular.
- Basal placentation is found in the Asteraceae family where one or a few ovules develop at the base of a simple or compound ovary.
- In the Axile, the carpels are folded inward and the ovules are present along the central axis of the ovary. This type of placentation occurs in Solanaceae and Liliaceae families.
So, the correct answer is ‘(a) Brassicaceae’.

Note:
- A compound ovary is an ovary formed by the union of two or more carpels.
- The leaves and shoots of plants are used in asthma, cough, and bleeding piles. They also act as an appetizer and stimulant.
- The seeds are used to treat bronchitis and fever. The flowers help in paralysis and impotency.
- The plants of this family are cultivated as vegetable crops. For eg., Brassica oleracea var. Botrytis, Brassica oleracea var. Caulorapa.