Draw the diagram of a microsporangium and lable its wall layers.Write briefly about the wall layers?

Explanation

The diagram representation of a microsporangium is shown below

In a transverse section a typical microsporangium is circular in outline and is surrounded by four wall layers.
(a) Epidermis : The epidermis is the outermost protective layer. It is composed of tangentially flattened cells . The cells are closely fitted and heve thick walls which is helpful in the dehiscence of anther.
(b) Endothecium it is present below the epidermis and expands radically with febrous thickenings, at maturity these cells loose water, at contract and help in dehiscence of pollen sac.
(c ) Well Layers it is present between well marked endothecium and tapetum. These are thin walled layers, arranged in one to five layers, which also help in dehiscence of anther.
(d) Tapetum it is the innermost wall layer with large cells ,thin cell walls abundent cytoplasm and have more than one nucid . Tapetum is a nutritive tissue which nourishes the developing pollen grains.
The centre of the microsporangium consists of sporogenous tissue which undergoes meiotic divisions to form microspore tetrads. This process is known as microsporogensis.