Question

Long question 7 marks.

Answer 1

Explanation:

The male gametophyte containing the generative cell splits into two sperm nuclei, one of which fuses with the egg, while the other degenerates. After fertilization of the egg, the diploid zygote is formed, which divides by mitosis to form the embryo. The scales of the cones are closed during development of the seed

Answer 2

Answer:

Androecium:

Androecium is the third whorl, which is the male reproductive part of the flower.

Unit:

Its units are called stamen.

Stamen:

Each stamen has a thread like filament at the free end of which anther is attached.

Anther:

Anther has pollen sacs in which haploid microspores (pollen grains) are produced through meiosis.

Process:

Each microspore germinates into the male gametophyte generation. During it, the nucleus of microspore undergoes mitosis ans produces two nuclei i.e. a tube nucleus and a generative nucleus. The generative nucleus again undergoes mitosis and produces two sperms. So, a germinated microspore has a tube nucleus and two sperms. All these structures are the male gametophyte generation of the plant.