Explain the role of tapetum in the formation of pollen grain wall.

Explanation

The main functions of tapetum are:
(a) Transportation of nutrients into another locule at the time of meiosis in spore mother cells,
(b) Secretion of enzymes and hormones,
(c) Production of Ubisch bodies which are coated with sporopollenin to cause thickening of exine,
(d) Secretion of special proteins for pollen to recognise compatibility.