Question

Draw a diagram showing germination of pollen on the stigma of a flower and mark on it the following organs/parts: (i) Pollen Grain (ii) Pollen tube (iii) Stigma (iv) Female germ cell

Answer 1

Pollen germination:

1. The collective event of pollen landing on the stigma, the development of pollen tubes, and the entry of pollen tubes into the embryo sac are known as pollen germination.
2. The germination of pollen begins with the landing of pollen grain on the stigma.

Pollen grains:

1. These are the microscopic compositions, which comprise androecium, that is, a male reproductive organ of a flower.
2. A specially adapted part of the pistil, which is modified for the reception of pollen is the stigma.
3. The pollen grain cell differentiates into two cells, one is bigger and known as the tube cell, and the other is smaller in size and known as the generative cell.

Pollen tube:

1. The intine develops out via the germ pore and produces a pollen tube.
2. The tube develops into the tissue of the style towards the ovary.

Stigma:

1. It is the part of the pistil, in which germination of the pollen takes place.
2. The pistil is the female reproductive part of a flower, comprising style, stigma, and ovary. The ovary is the female organ of a flower, which is an enlarged basal part of the pistil.

Female germ cell:

1. Within the ovary of the pistil, the female germ cells or ovules are located.
2. Post fertilization, the ovules turn into a seed, while the ovary turns into a fruit.