Question

Describe the process of development of male gametophyte in angiosperms with suitable diagrams

Answer 1

Development of male gametophyte in angiosperm

Explanation:

• Microsporogenesis : It is the process of formation of microspore from PMC (Pollen Mother Cells). and development is occur in anther, from meosis the sponogenous tissue gamets form microscrope tretrad.
• Each cell of sporogenous tissue has capacity to give rise to a tetrad. Hence, each cell is a  PMC.
• Micro spore or the pollen grain represents the initial cell of male gametophyte.
• During germination, the cytoplasm of the pollen grain comes out in the form of a tube like structure called pollen tube through the germ pore.
• The pollen tube carries the tube nucleus cytoplasm and generative cell.
• The pollen tube grows through the style towards the ovule due to some chemical stimulus inside the ovary.
• Pollen tube consisting of the two male gametes and a degenerating tube nucleus represents the male gametophyte.

Answer 2

Development of male gametophyte

There is 2 different stages in the life cycle of plants:

1. Gametophyte 2. Sporophyte                                                                                          

the male gametophyte is haploid. the development of gamatephyte takes place in the microsporangium.

The nucleus of microspore divides to form a vegetative and a generatitive nucleus.A wall is laid around the generative nucleus resulting in / the formation of two unequal cells, a large irregular nucleus bearing with abundant food reserve called vegetative cell and a small generative cell. At this 2 celled stage, the pollens are liberated from the anther. In some plants the generative cell again undergoes a division to form two male gametes. In these plants,the pollen is liberated at 3 celled stage. In 60% of the angiosperms pollen is liberated in 2 celled stage. Further, the growth of the male gametophyte occurs only if the pollen reaches the right stigma. The pollen on reaching the stigma absorbs moisture and swells. The inline grows as pollen tube through the germ pore. Incase the pollen is liberated at 2 celled stage the generative cell divides in the pollen into 2 male cells (sperms) after reaching the stigma or in the pollen tube before reaching the embryo sac.