Match List I with List II: List I (Placentation) i. Marginal ii. Axile iii. Parietal iv. Basal List II (Example) a. Mustard b. Pea c. Marigold d. Lemon Choose the correct answer from the options given below:

i – b, ii – d, iii – a, iv – c

i – a, ii – c, iii – b, iv – d

i – d, ii – b, iii – a, iv – c

i – c, ii – a, iii – d, iv – b

Placentation

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NCERT Class 11 · Morphology of Flowering Plants · 4 NEET questions

Do not confuse Placentation with Placentation in mammals. In plants, it is the spatial arrangement of ovules within the ovary. Misidentify the ovary position, and you lose the entire question.

The idea

Placentation refers to the arrangement of ovules within the ovary. It is classified into marginal, axile, parietal, basal, central, and free central types. Marginal placentation is characteristic of the Fabaceae family. Axile is seen in multilocular ovaries like China rose, while parietal occurs in syncarpous ovaries where ovules develop on the inner wall.

Why it matters

It ensures the efficient distribution and nourishment of ovules within the ovary to maximize reproductive success.

NEET lens

NEET asks for direct examples. Memorize: Marginal (Pea), Axile (China rose, Tomato, Lemon), Parietal (Mustard, Argemone), Free central (Dianthus, Primrose), and Basal (Sunflower, Marigold). Diagrams are high-yield; identify the cross-section correctly. Do not skip the family-specific examples as they are frequent match-the-following targets.

Clinical significance

In botany, failure of proper placentation leads to seed abortion or infertile fruits, disrupting the ecosystem's food chain. Similarly, in human embryology, placental insufficiency leads to intrauterine growth restriction (IUGR). Both systems rely on precise nutrient transfer mechanisms for survival.

Introduction

Placentation is the arrangement of ovules (placentae) within the ovary, varying by how the placenta — tissue bearing ovules — is positioned.

Core concept

Types: Marginal — placenta along ventral suture, one chamber (pea). Axile — placenta at central axis, multilocular (China rose, tomato, lemon). Parietal — on ovary wall, unilocular (mustard, Argemone). Free central — placenta free column in center, no septa (Dianthus, Primrose). Basal — single ovule at base (sunflower, marigold).

Go deeper

Axile placentation in multilocular ovaries means the ovary has multiple chambers (locules) with septa. Each locule has ovules attached to the central axis. This is common in Malvaceae and Solanaceae.

From Class 10

Ovules develop into seeds inside the ovary. The way ovules are attached inside the ovary is called placentation.