Question

In gymnosperms, how many male gametes are produced by each pollen grain?

• A. 4
• B. 3
• C. 1
• D. 2

Answer 1

Answer: (D)

In gymnosperms, the pollen grain or the male gametophyte is formed from the microspores. Microspores are liberated at various stages in gymnosperms, at the 3-celled, 4-celled or 5-celled stage but ultimately 2 male gametes are formed.

Let's take the example of Cycas in which microspores are released at the 3-celled stage in the air. At this stage, the microspore is having a prothallial cell and a small generative cell and a large tube cell. Further development of this 3-celled male gametophyte takes place in the pollen chamber of the ovule after pollination. This generative cell then divides to form a stalk cell and a body cell. The stalked cell doesn't divide further while the body cell divides to form 2 male gametes known as antherozoids.

So, the correct answer is C.