Question

What is Microsporogenesis?

Answer 1

Hint: It is defined as the formation of microscopes inside the microsporangia of seed plants. It occurs inside the pollen sac of another. Pollen is the first cell of the male gametophyte. It is generally spherical, measuring about 25-50 mm in diameter. Pollen grains have a hard covering on their outer surface which helps to survive thousands of years and are called a pollen grain.

Complete answer:
When another develops, the cells of the sporogenesis tissue undergo meiotic divisions to form microscope tetrads. Each one is a potential pollen or microspore mother cell. The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called microsporogenesis. The nucleus of a pollen grain divides mitotically to form a vegetative and generative nucleus. When another matures and dehydrates, the micropores dissociate from each other and develop into pollen grains.
Structure of microspore:
It is a unicellular cell and haploid
The wall of the pollen grain is called sporoderm. It is made up of two layers:
1. Exine- Outer and thick layer made up of sporopollenin. It is the biologically most resistant substance and also helps to preserve the pollen grain for thousands of years
2. Intine is the inner layer and it is thin and uniform. It is made up of pectin-cellulose. At the time of pollen germination, from intine through the germ pore pollen tube comes out.
The cytoplasm is rich in nutrients.

Note:
Mature male gametophyte of angiosperm is 3-celled, 3- nucleated, and formed by one meiosis and two mitosis. Pollen tube secretes cytokinins and auxins to stimulate the ovary. In over 60% of flowering plants, pollen grain is shed at the 2-celled stage. It is formed by one meiosis and one mitosis.