Question

In a polycarpellary and syncarpous pistil, ovary can be unilocular or multilocular and placentation can be?
A. Free-Central or parietal.
B. Parietal or marginal.
C. Marginal or free central.
D. Parietal or axile.

Answer 1

Hint: Placentation is the arrangement of ovules within the ovary. Placenta is a cushion-like structure that helps to hold the ovule inside it. It’s like a protective covering which covers the developing embryo inside it from outer distractions. Be it in animals or plants have also the same use. The placenta is arranged in different types. Now let us discuss the types. An umbilical cord can be compared to the plant component.

Complete answer:
Option A Free-Central or parietal: In free central placentation the ovules are borne on the central axis and septa are absent. For example- The ovules develop on the inner wall of the ovary or on the peripheral section in dianthus and primrose, as well as in parietal placentation. The ovary is one-chambered at first, but due to the creation of the false septum, it becomes two-chambered. For example- mustard and argemone, cucumber.
So, option A is not correct.
Option B Parietal or marginal: The ovules develop on the inner wall of the ovary or the peripheral region in the parietal placentation. The ovary is one-chambered at first, but due to the creation of the false septum. It becomes two-chambered. The placenta develops a ridge along the ventral or front part of the ovary in marginal placentation, and they form in rows.
So, option B is not correct.
Option C Marginal or free central: Marginal placentation is the earliest type of placentation. In marginal placentation, the placenta forms a ridge along the ventral or front half of the ovary, and the ovules are borne in two rows along this ridge. Pea is a good example. Marginal placentation is the type of placentation that may be seen in sweet pea, also known as (Pisum sativum).
So, option C is not correct.
Option D Parietal or axile: The placenta considered to be axile in axile placentation. When it is axial and the ovules linked to it in a multilocular ovary. For example, china rose, tomato, lemon, and lily. Ovules form on the inner wall of the ovary or the periphery in the parietal placentation. The ovary one-chambered at first, but due to the creation of the false septum. It becomes two-chambered. For example- mustard and argemone, cucumber.
So, option D is correct.

Hence, Option D is the correct answer.

Note:
The function of the placentation is to transfer and provide nutrients, water and other essential growth factors to the developing embryo. The placentation is frequently of taxonomic value. Placentation is mostly submarginal in a simple pistil which a female sex organ. Two or more carpels are used in various ways in a compound pistil, with placentation being parietal and carpels joined. Angiosperm plants are known for their placentation.