What is the Role Of Tapetum in Anther Development

The tapetum plays a crucial role in the development of the anther and the formation of pollen grains (male gametophytes) in flowering plants. It is the innermost layer of the anther wall and surrounds the developing microspores (pollen mother cells and later, pollen grains).

Here’s a detailed breakdown of its role:

Role of Tapetum in Anther Development

1. Nutritional Support

   • The tapetum provides essential nutrients and enzymes to the developing microspores.

   • It acts as a source of lipids, amino acids, sugars, and proteins necessary for pollen development.

2. Secretion of Sporopollenin Precursors

   • The tapetum produces and secretes precursors for sporopollenin, a tough, durable polymer that forms the exine (outer layer) of pollen walls.

   • Sporopollenin is crucial for the protection and viability of pollen.

3. Formation of Pollen Wall (Exine and Intine)

   • It assists in the deposition of materials that form the structured layers of the pollen wall.

   • The exine patterning is influenced by tapetal secretions.

4. Production of Enzymes

   • The tapetum secretes enzymes such as callase, which break down the callose wall surrounding tetrads of microspores, enabling the release of individual pollen grains.

5. Synthesis of Pollen Coat (Tryphine)

   • In species with orbiculate tapetum, it contributes to the pollen coat (also called tryphine), which aids in pollen-stigma interaction and pollen recognition.

6. Programmed Cell Death (PCD)

   • The tapetum undergoes programmed cell death at a specific stage, which is essential for the release of its contents into the anther locule to support pollen maturation.

Types of Tapetum

There are mainly two types based on behavior:

1. Secretory (Glandular) Tapetum

   • Remains intact while secreting substances into the anther locule.

2. Amoeboid (Invasive or Periplasmodial) Tapetum

   • Tapetal cells break down early and form a plasmodial mass that directly surrounds the microspores.

Summary

In conclusion, without a functional tapetum, normal pollen development is impaired, often leading to male sterility.