Question

Monothecous and basifixed anthers occur in
(A) Tomato
(B) Onion
(C) Cotton
(D) Pea

Answer 1

We know that every plant has its unique characteristic features, which can be seen in each of its parts like root, stem, leaves, flowers, fruits etc. The anthers are a part of the male reproductive organs of the plants and they carry the pollen grains or microsporangia.

Complete answer:
The male reproductive part consists of stamen which has a stalk like structure called filament that holds the anther on top. The anther is swollen and contains sac-like structures called anther lobes. Based on these lobes, the anthers are categorised as monothecous and dithecous anther.
Monothecous anthers have a single lobe with two pollen chambers in it. They are also called bisporangiate as they have two pollen chambers. Example: Hibiscus rosa-sinensis, cotton, Cannaceae.
Dithecous anthers have two lobes with two pollen chambers in each. As they have four pollen chambers they are also known as tetrasporangiate. Example: Family Solanaceae, Liliaceae, Cruciferae.
Similarly, based on the position the anthers are attached to the stamen, it can be divided as,
Basifixed: In this type, the anther is attached at its base to the filament. Example: Mustard, cotton.
Dorsifixed: The anthers attached medially and dorsally on the apex of the filament is known as dorsifixed anthers. Example: Passion flower.
Versatile: The lobes are attached to the filament in the center with two free ends. Example: Gramineae family.
Adnate: The anthers that are attached to the filament through the whole length belong to this type. Example: Magnolia.

Thus, monothecous and basifixed anthers occur in (C) Cotton.

Note:
The anthers can be found in many shapes such as linear, reniform, rounded, sinuous or sagittate. The pollens produced from the anther is not a male gamete by itself. After they adhere to the stigma of a female flower, they germinate there by absorbing the moisture and producing male gametes.