Question

From one Pollen grain, How many male gametes can be produced maximally.
A. 2
B. 4
C. 8
D. 6

Answer 1

Hint: Pollen grains are produced from the anther of the flower. It helps in the transfer of genetic material during the cross and also undergoes self-pollination. The pollen grains have a double wall, consisting of a thin inner wall called an endospore and a thick outer wall called an exosphere.

Complete answer: The process of formation of microspores or male gamete from a pollen mother cell through meiosis is called microsporogenesis. The microspores are arranged in a cluster of four cells known as microspore tetrad. As anthers mature and dehydrate, the microspores dissociate from each other and develop into thousands of pollen grains. Each microsporangium has several thousands of pollen grains that are formed that are released with the maturation of anther. The pollen grain has an outer layer called exine and an inner layer called intine. The pollen grain has two cells:- vegetative cells and germinative cells. When the pollen grain gets matured it has two cells, the vegetative cell, and the generative cell. The vegetative cell is bigger, has an abundant food reserve, and a large irregularly shaped nucleus. The generative cell is small as compared to the vegetative cell and it floats in the cytoplasm. This generative cell then divides and forms the two male gametes. So, the total number of gametes produced by pollen is two.
Hence, the right answer is Option A-(2).

Note: Pollen grains are spherical measuring about 25-50 micrometres in diameter. It has a prominent two-layered wall. The hard outer layer called the exine. It is made up of sporopollenin which is one of the most resistant materials. It can tolerate high temperatures and strong acids and alkali. No enzyme can destroy the sporopollenin. Pollen grains can be well-preserved in fossil form because of the presence of sporopollenin. The inner wall of the pollen grain is called the intine. It is a thin and continuous layer. This layer is made up of cellulose and pectin.