Question

The germination of pollen grains takes place on_________ of the flower.
A) Calyx
B) Corolla
C) Anther
D) Stigma

Answer 1

Pollen grains are small and microscopic structures which carry reproductive cell. On germination, the cell of the pollen grain divides into two cells one of these is smaller in size and is called generative cell and the bigger part is known as tube cell.

Complete answer:
Let us analyse the options to find the correct answer.
Before we find the correct answer, let us know a little bit about flowers. Flowers are the reproductive parts of a plant and they are also a source of food for insects. A flower has various parts as we can see in the diagram below.
Option A: Calyx is the outermost part of the flower. It consists of sepals, which covers and protects it as they develop. After flowering calyx has no more function to perform and they become vestigial. Morphologically, both sepals and petals are modified leaves. Hence, A is incorrect.
Option B: Corolla are present beneath the calyx and are generally colourful. Main function of corolla is to attract insects towards itself which results in the process of pollination. In some cases Calyx and Corolla fuse together and are termed as perianth. Hence, option B is incorrect.
Option C: Anther is male part of the flower. Anther is the part of stamen where pollen is produced within the microsporangia. It is a knob-like structure which usually consists of two lobes which are joined together by the connective tissue. Hence, option C is incorrect.
Option D: The female elements are collectively called the pistil. The top part is called stigma which has a sticky surface and is receptive to pollen grains. So the germination of pollen grains takes place on the stigma of the flower. Hence, option D is correct.

Hence the correct answer is option ‘D’.

Note: After the germination of pollen grains starts, a pollen tube is produced and it acts as a pathway for sperm to reach the egg. The pollen tube reaches the ovule where there is fertilization between the sperm and egg. Hence, the fertilized egg begins the cell divisions to develop into an embryo.