Problem 60 - Objective Biology for NEET

Question

Select the correct matching: Column I Column II \(\quad\) Column III 1\. Hypogynous A. Gynoecium occupies the highest \(\quad\) X. Mustard, Brinjal, China rose position 2\. Epigynous B. Gynoecium is situated in the centre Y. Plum, peach, rose 3\. Perigynous C. Margin of thalamus grows upward Z. Guava, cucumber, ray florets enclosing ovary completely of sunflower (a) \(1-\mathrm{A}-\mathrm{X}, 2-\mathrm{B}-\mathrm{Y}, 3-\mathrm{C}-\mathrm{Z}\) (b) \(1-\mathrm{A}-\mathrm{X}, 2-\mathrm{C}-\mathrm{Z}, 3-\mathrm{B}-\mathrm{Y}\) (c) \(1-\mathrm{B}-\mathrm{Y}, 2-\mathrm{A}-\mathrm{X}, 3-\mathrm{C}-\mathrm{Z}\) (d) \(1-\mathrm{A}-\mathrm{X}, 2-\mathrm{B}-\mathrm{Z}, 3-\mathrm{C}-\mathrm{Y}\)

Step-by-Step Solution

Answer

The correct matching of the columns is: 1-A-X, 2-B-Z and 3-C-Y. So the correct answer is (b).

Step 1: Match the Plant Structures

First match the correct structures. Hypogynous, Epigynous and Perigynous mean respectively: gynoecium occupies the highest position (A), gynoecium is situated in the centre (B) and margin of thalamus grows upward enclosing ovary completely (C). So it matches as: 1-A, 2-B and 3-C.

Step 2: Match the Examples

Now match the correct species as examples. Mustard, Brinjal and China rose (X) are Hypogynous, which means their gynoecium occupies the highest position. Plum, peach and rose (Y) are Perigynous meaning the margin of thalamus grows upward enclosing ovary completely. Guava, cucumber and sunflower (Z) are Epigynous having their gynoecium situated in the centre. Hence, the matching for the examples is 1-X, 2-Z, 3-Y.

Step 3: Complete Match

From Step 1 and Step 2, the correct matches are 1-A-X, 2-B-Z and 3-C-Y.

Key Concepts

Understanding Hypogynous Flowers

When we talk about hypogynous flowers, we refer to a particular arrangement where the gynoecium, or female reproductive part of the flower, occupies the highest position above the other flower parts. This configuration allows for superior ovaries, meaning they are above the attachment point of the petals and sepals.

Examples of plants with hypogynous flowers include Mustard, Brinjal, and China rose. In these flowers, you will notice that the ovary stands proud at the top, which is not just an interesting botanical fact. It has implications for how the plant is pollinated and can affect the effectiveness of pollinators like bees and butterflies in accessing the nectar and transferring pollen.

Exploring Epigynous Flower Structure

In contrast to hypogynous flowers, epigynous flowers feature a gynoecium that is situated below the other flower parts. Specifically, the ovary is embedded in the receptacle and the other parts of the flower arise above it. This positioning means that the ovary is inferior or below the point of attachment.

Plants like Guava, cucumber, and the ray florets of sunflower showcase this flower arrangement which is termed ‘epigynous’. An interesting adaptation of epigynous flowers is that they often protect their ovaries within the receptacle, which may aid in defending against pests and disease. Additionally, since the ovary is below the level of the petals and sepals, the visual appeal of the flower might be enhanced, potentially luring pollinators more effectively.

Perigynous Flowers and Their Unique Form

Perigynous flowers strike a balance between the previous types. Their gynoecium is situated in the center of the flower with the margin of the thalamus, or floral cup, growing upward and partially enclosing the ovary without completely covering it.

This results in a partially inferior ovary, a distinguishing characteristic of plants like Plum, peach, and rose. The perigynous flower structure is particularly notable because it creates a sort of shallow cup or floral tube at the base of the flower where the petals and sepals connect. This cup may aid the flower in collecting and directing rainwater or dewdrops toward the ovary, a feature that could possibly assist in the reproductive process.