Question

Marginal placentation is found in
(a) Solanaceae
(b) Cruciferae
(c) Fabaceae/Leguminosae
(d) Asteraceae/Compositae

Answer 1

Hint: Placentation is related to the placenta, which is the nutritive and protective tissue that surrounds an embryo. In the case of plants, it refers to the arrangement of ovules in the ovary of the plant. Marginal placentation is observed in plants whose ovules are lined up along a ridge on one side of the ovary.

Complete answer:
- Placentation in the formation, type, arrangement, and structure of the placenta in living organisms such as mammals and angiosperms.
- The placenta in plants is the area of the carpel to which the ovules are attached.
- Marginal placentation is a feature of the Fabaceae/Leguminosae family. The flowers show a monocarpellary unilocular ovary and the ovules are borne on rows near the margin on the placenta formed along the ventral suture.

Additional Information:
- The area of attachment of the ovules are known as sutures, where the marginal traces occur. It is the locus where the Ancestral Carpel fused to create an enclosed space known as a locule.
- There are six different forms of placentation in plants: 1. Marginal 2. Parietal 3. Axile 4. Free-central 5. Superficial 6. Basal.
- Examples of plants with the types of placentation are as follows: Parietal - Papaveraceae, Axile: Solanaceae, Free-central: Primulaceae, Superficial (Laminar) : Nymphaea, Basal: Compositae.
So, the correct answer is ‘(c) Fabaceae/Leguminosae’.

Note:
- Placentation also occurs in fish, reptiles, amphibians, and a variety of invertebrates.
- In mammals, the placenta is an organ that is formed from the blastocyst after implantation.
- The types of placentation in mammals during gestation are endotheliochorial, epitheliochorial, and hemochorial placentation. Dichorionic and monochorionic placentation occur in the case of twins.