Division taking place in tapetum cell is -a)Meiosisb)Amitosisc)Endomitosisd)Only mitosisCorrect answer is option 'C'. Can you explain this answer?

Question

Answer

Schematic of

anther

( 1:

Filament

2:

Theca

3: Connective 4:

Pollen sac

or Microsporangium)

Section of anther, showing

dehiscence

and release of pollen (1:

Vascular bundle

2: Epidermis 3: Fibrous layer 4: Tapetum 5: Pollen

The tapetum is a specialised layer of nutritive cells found within the anther, of flowering plants, where it is located between the sporangenous tissue and the anther wall. Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat.^[1] The cells are usually bigger and normally have more than one nucleus per cell. As the sporogenous cells undergo mitosis, the nuclei of tapetal cells also divide. Sometimes, this mitosis is not normal due to which many cells of mature tapetum become

multinucleate

. Sometimes polyploidy and polyteny can also be seen. The unusually large nuclear constitution of the tapetum helps it in providing nutrients and regulatory molecules to the forming pollen grains. The following processes are responsible for this:

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Endomitosis
Normal mitosis not followed by cytokinesis
Formation of restitution nuclei
Endoreduplication

Answer

Endomitosis in Tapetum Cell Division

In tapetum cells, division occurs through a process called endomitosis. Endomitosis is a type of cell division where the nuclear division takes place without the subsequent cytokinesis, resulting in cells with multiple nuclei. This process is essential for the development and function of tapetum cells in plants.

Process of Endomitosis

- Endomitosis starts with the replication of DNA in the nucleus of the tapetum cell.
- The replicated chromosomes then undergo multiple rounds of condensation and segregation, leading to the formation of multiple sets of chromosomes within the same cell.
- Unlike in normal mitosis where the cell divides into two daughter cells, in endomitosis, the cell retains all the nuclei within a shared cytoplasm.
- This results in the formation of cells with multiple nuclei, which is a characteristic feature of tapetum cells.

Significance of Endomitosis in Tapetum Cells

- The process of endomitosis in tapetum cells allows for the accumulation of nutrients, proteins, and other essential molecules required for pollen development.
- The presence of multiple nuclei in tapetum cells facilitates the synthesis and secretion of various compounds that are essential for pollen wall formation and pollen maturation.
- Endomitosis also plays a crucial role in providing mechanical and structural support to the developing pollen grains.

Conclusion

Endomitosis in tapetum cells is a unique process of cell division that is crucial for the development and function of tapetum cells in plants. By undergoing endomitosis, tapetum cells are able to support the growth and maturation of pollen grains through the synthesis and secretion of essential compounds.

Answer

Division taking place in tapetum cell is:
The correct answer is C: Endomitosis.
Explanation:
Endomitosis is a type of cell division that occurs in tapetum cells. Here is a detailed explanation:
- Tapetum cells: Tapetum cells are a specialized layer of cells found in the anther of a flower. They provide nourishment and support to the developing pollen grains.
- Endomitosis: Endomitosis is a form of cell division where the nuclear division occurs without cytokinesis, resulting in the formation of cells with multiple nuclei. It is a common process in the tapetum cells.
- Meiosis: Meiosis is a type of cell division that occurs in reproductive cells (gametes) to produce haploid cells with half the number of chromosomes. It is not involved in the division of tapetum cells.
- Amitosis: Amitosis is a primitive form of cell division where the nucleus simply divides into two without the formation of a spindle or the involvement of other cellular structures. It is not the type of division that occurs in tapetum cells.
- Only mitosis: Mitosis is a type of cell division that results in the formation of two genetically identical daughter cells. While mitosis may occur in tapetum cells, it is not the only type of division that takes place in these cells.
In conclusion, the division taking place in tapetum cells is endomitosis, where nuclear division occurs without cytokinesis, resulting in cells with multiple nuclei.

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