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

Explanation

Tapetum is the innermost layer of the micorsporangium. It produces the exine layer of the pollen grains, which is composed of the sporopollenin, the most resistanct fatty substance.
During microsporogenesis, the cells of tapetum produce various enzymes hormones, amino acids and other nutritious materials required for the development of pollen grains.