Question

Tapetum is

• A. Parietal in origin
• B. Inner most wall layer of pollen sac
• C. Nutritive and provides wall material to pollen grains
• D. All the above

Answer 1

Answer: (D)

All the above

A young anther has a homogeneous mass of hypodermal cells which is surrounded by a single layer of Epidermis. Below the epidermis, some cells contain prominent nucleus and dense cytoplasm. These cells are called archesporial cells which divide periclinally to form an outer group of cells called parietal cells and an inner group of cells called sporogenous cells. The cells of the parietal group divide by periclinal and anticlinal divisions and form 2-5 layered anther wall. The anther wall consists of four layers: Epidermis followed by single layered Endothecium, 2-3 middle layers and a single layer of Tapetum. Tapetum is the innermost layer and completely surrounds the sporogenous tissue. The cells of Tapetum have dense cytoplasm and generally have more than one nuclei. Tapetum nourishes the developing pollen grains. Tapetum cells also secrete ubisch bodies or orbicules which get a coating of sporopollenin and helps in the exine formation i.e. outer wall of a pollen grain. Thus, Tapetum also contributes to the wall material of the pollen grains.

Hence all the options given in the question are correct.

So, the correct answer is D.