Describe internal structure of microsporangium.

A typical microsporangium appears near circular in outline.

It is generally surrounded by four wall layers.

They are epidermis, endothecium, middle layers and the tapetum.

The outer three wall layers perform the function of protection and help in dehiscence of anther to release the pollen.

The innermost wall layer is the tapetum. It nourishes the developing pollen grains.

Cells of the tapetum possess dense cytoplasm and generally have more than one nucleus.

Tapetum secretes enzyme and hormone both and special protein. It decides correspondence of pollen grain

The cells of epidermis are stretched or scattered or flat.