Question

How many male gametes are essential to form 25 seeds in angiospermic plants?
A. 25
B. 50
C. 75
D. 100

Answer 1

Hint: Inside a pollen grain or a pollen tube, the male angiosperm gametes consist of two sperm cells. They are derived from a single generative cell that, after meiosis, is shaped as a smaller cell by unequal cell division in the microspore.

Complete answer:
The roles of the gametophytes are the development and fertilisation of sperm cells and female cells and their union. The pollen grain is the male gametophyte in flowering plants, and the embryo sac is the female gametophyte. The male gametophyte inside the anther completes its early development.

The gametophyte-producing egg is recognised as a megagametophyte and the gametophyte-producing sperm as a microgametophyte. The microgametophyte in seed plants is called pollen. When the pollen grains leave the sporangium, seed plant microgametophytes consist of two or three cells. Within the megaspore of established seedless vascular plants and within the megasporangium in a cone or flower in seed plants, the megagametophyte grows.

The microgametophyte (pollen grain) moves in seed plants to the vicinity of the egg cell (carried by a physical or animal vector) and by mitosis releases two sperm.

The male and the female gamete unite in the angiosperm plants to form the zygote. To form the endosperm, the other male gamete fuses with the secondary nuclei. Zygote and endosperm will come out of the seed together. 50 male gametes will entail the creation of 25 seeds, of which 25 male gametes will fuse with 25 egg cells.

Hence, the correct answer is option (B)

Note: The development of male gametophytes can be divided into two phases:
Creation of pre-pollination and post-pollination. The angiosperm male gametophyte is composed of one tube cell and one generative cell. To form two male gametes, this generative cell divides. Thus the male gametophyte angiosperm is 3-celled.