What is tapetum? How it's fromed?

The tapetum is the innermost layer of the anther wall in flowering plants. It surrounds the sporogenous tissue (microspore mother cells) inside the pollen sac and plays a vital role in the nutrition and development of pollen grains.

Structure & Position

• Located inside the anther, just outside the developing pollen grains
• Usually single-layered, but cells are large and rich in cytoplasm
• Can be of two main types:
  • Secretory (Glandular) tapetum
  • Amoeboid (Plasmodial) tapetum

Functions of Tapetum

1. Nutrition Supply

   • Provides essential nutrients to developing microspores

2. Pollen Wall Formation

   • Produces sporopollenin precursors for exine (outer wall of pollen)

3. Secretion of Enzymes

   • Helps in dissolving callose wall around tetrads for microspore release

4. Formation of Pollenkitt

   • Produces sticky substances that help in pollination

5. Regulation of Pollen Development

   • Controls proper maturation of pollen grains

How Tapetum is Formed?

• The anther develops from a group of archesporial cells.

• These cells divide to form:

  • Primary sporogenous cells (→ microspore mother cells)
  • Primary parietal cells

• The parietal cells further divide to form the anther wall layers:

  1. Epidermis
  2. Endothecium
  3. Middle layers
  4. Tapetum (innermost layer)

 Thus, the tapetum originates from the inner secondary parietal layer.

Labelled Diagram of Tapetum in Anther

🔍 Diagram Explanation

• Epidermis – outermost protective layer
• Endothecium – helps in anther dehiscence
• Middle layers – temporary layers
• Tapetum – innermost nutritive layer
• Microspores/Pollen grains – located inside

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The tapetum is a specialized nutritive layer of the anther that supports pollen development, wall formation, and maturation, making it essential for successful plant reproduction.