Question

Draw the diagram of a microsporangium and label its wall layers. Write briefly on the role of the endothecium.

Answer 1

Microsporangium

The pollen sacs present in the lobes of the anther are called microsporangia.The male gametophyte (pollen grains) are produced through the process of microsporogenesis in the microsporangia.

Layers of microsporangium

Layers of sporangium-
● Outer single layer is called epidermis.
● Second layer is called endothecium, which is thick
and fibrous.
● Third layer are called middle layers, which disintegrate after maturation
● Inner layer is called tapetum which is nucleated tapetal cells with dense cytoplasm.


Role of the endothecium

• Protection- Along with the epidermis and middle layers the endothecium provides protection to the pollen grains.
• Dehiscence- Endothelial cells are thickened unevenly with lignin. This results in the thinner walls of the cell to stretch to a greater extent, creating a tension. This tension leads to dehiscence (splitting) of the anther, releasing the pollen grains.