Role of tapetum in the formation of pollen grain wallTapetum is the

✅ Role of tapetum in the formation of pollen grain wall

Tapetum is the innermost wall layer of anther. The cells of this layer have large nuclei and dense cytoplasm. This layer is of great physiological importance as most of the food material from outside passes through this layer. At maturity, these cells degenerate and provide nourishment to developing microspores or pollens inside. Tapetum is the layer, which secretes both enzymes and substances of hormonal nature.

The main function of tapetum is to provide nutrition to pollens but it also secretes some substances of utmost importance like :

➖ Qallase enzyme : Tapetum secretes callase enzyme which dissolves callose substances by which four pollens of a pollen tetrad are united, hence separating microspores or pollens of a tetrad.

➖ Ubisch bodies : These bodies of lipid nature are also secreted by tapetum. Ubisch bodies get covered with sporopollenin and thus increase thickness of exine (i.e., outer layer of pollen wall). Ubisch bodies are spheroidal and have diameter of only few microns. These are produced only by glandular tapetum (not by amoeboid tapetum).

➖ Pollen kit substances : Tapetum also secretes pollen kit, outer most oily, thick, viscous, sticky, electron dense homogeneous coating of pollen grains of many entomophilous plants.