Tarentum

Microsporangia and Microsporogenesis

Microsporogenesis is the meiotic division of microspore mother cells into microspores.

The anther is the reproductive portion of the stamen. Two lobes link each anther. Two pollen chambers run longitudinally through each anther lobe. There are enough pollen microspores in the microsporangium to keep it going.

Microsporangia’s Structure

Microsporangia are made up of the following microorganisms:

Tarentum: This layer is one of the innermost layers of the wall, and the cells are multinucleated.

Three to four layers of thin-walled cells form the middle layer. Just beneath the endothelium, they can be found.

The epidermis is separated from the endothecium by a layer. The endothelium is formed by a certain type of cell.

Epidermis: The epidermis is the single layer of skin that protects the body from the elements. In Arceuthobium, epidermal cells.

Anther development and microspore production (pollen grains):

1. The immature anther is made up of a homogeneous mass of parenchymatous cells encased in epidermis. It quickly grows four lobed.
2. Some hypodermal cells begin to operate as archesporial initials in each of the four lobes.
3. An outer primary parietal cell and an inner primary sporogenous cell divide from each archesporial beginning.
4. The endothecium, middle layers, and tapetum split from the main parietal cell to generate 3-5 wall layers.
5. The primary sporogenous cells divide to form a mass of sporogenous cells, also known as microsporocytes.
6. Each microspore mother cell divides meiosis to produce four haploid microspores of pollen grains, which remain in tetrads.

Development prior to pollination:

1. Precocious microspores germinate in situ (i.e., while still trapped inside the microsporangium or pollen sac).
2. The nucleus of the microspore divides mitotically, resulting in a smaller generative cell close to the spore wall and a much larger vegetative cell (or tube cell).
3. Around the generative cell, a callose layer is formed. The generative cell separates from the microspore wall and becomes free in the cytoplasm.
4. After that, the callose layer disappears. At this bicelled stage, the pollen grains are discharged from the anther (rarely three celled).

Development following pollination:

1. Pollination is the process of transferring the released pollen grains to the receptive surface of the carpel (i.e. the stigma).
2. Within a few minutes, the pollen grain on the stigma absorbs water and swells.
3. The vegetative (or tube) cell grows in size and emerges as a pollen tube through one of the apertures.
4. Intine extends from the pollen tube’s wall. To make a passage for itself to enter, the tube secretes exogenous pectinases and other hydrolytic enzymes.
5. The pollen tube, with the farmer laying at its tip, transports the vegetative and generative nuclei.
6. The generative cell splits into two male gametes that are not motile.
7. The tube nucleus serves no use.
8. The tube nucleus serves no purpose and may dissolve.

Conclusion

Flowering plants, often known as angiosperms, reproduce in a sexual manner. Plant reproduction is primarily centered on the flower, which contains both male & female gametes. Even though some components of a bloom are sterile, they all help in the reproduction process. To comprehend the process of flower reproduction in flowering plants, we must first examine the many sections of the flower and their activities.