Tapetal cells (of the anther) commonly become bi-nucleate through a process called endomitosis (or nuclear division without cytokinesis).
How it happens:
- Normal mitotic division begins inside a tapetal cell.
- The nucleus divides (karyokinesis occurs).
- However, cytokinesis (cell division) does not take place.
- As a result, two nuclei remain within a single cell, making it bi-nucleate.
Key mechanism:
- This process is often referred to as endomitosis or endomitotic division.
- In some cases, repeated cycles can even lead to multinucleate or polyploid tapetal cells.
Why this occurs:
Tapetal cells are highly metabolically active and play a crucial role in pollen development (nutrition, enzyme secretion, sporopollenin precursors).
Having two or more nuclei:
- Enhances metabolic capacity
- Supports rapid synthesis of materials needed for pollen wall formation
In short:
đ Tapetal cells become bi-nucleate because nuclear division occurs without cell division, resulting in two nuclei within one cell.
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