Question

Correct position of floral parts over thalamus in mustard plant is :

• A. Gynoecium occupies the highest position, while the other parts are situated below it.
• B. Margin of the thalamus grows upward, enclosing the ovary completely, and other parts arise below the ovary.
• C. Gynoecium is present in the centre and other parts cover it partially.
• D. Gynoecium is situated in the centre, and other parts of the flower are located at the rim of the thalamus, at the same level

Answer 1

The Correct Option is A

To determine the correct position of floral parts over the thalamus in the mustard plant, we need to understand the basic structure and arrangement of a typical mustard flower.

In mustard plants, which belong to the family Brassicaceae, the flower exhibits a specific floral arrangement called hypogynous arrangement. In a hypogynous flower:

• The gynoecium, which is the female reproductive part of the flower, occupies the highest position on the thalamus (receptacle).
• The other floral parts such as the sepals, petals, and stamens are arranged below the gynoecium.

This arrangement ensures that the ovary is superior to the other parts of the flower. Hence, the correct statement is:

"Gynoecium occupies the highest position, while the other parts are situated below it."

Let's briefly evaluate the given options:

• Option 1: "Gynoecium occupies the highest position, while the other parts are situated below it." - This describes the hypogynous arrangement, which is characteristic of mustard flowers.
• Option 2: "Margin of the thalamus grows upward, enclosing the ovary completely, and other parts arise below the ovary." - This describes a perigynous or epigynous condition, which is not typical of mustard flowers.
• Option 3: "Gynoecium is present in the centre and other parts cover it partially." - This could refer to a perigynous or a different arrangement, not typical of mustard.
• Option 4: "Gynoecium is situated in the centre, and other parts of the flower are located at the rim of the thalamus, at the same level." - This describes a perigynous arrangement, which does not apply to mustard flowers.

The correct and typical flowering arrangement for the mustard plant is indeed hypogynous, where the gynoecium is at the topmost position on the thalamus.