Which is the outermost and innermost wall layers of microsporangium in an anther ?

Epidermis and tapetum.

The correct answer is Option (3) -Epidermis and tapetum.

The outermost and innermost wall layers of microsporangium in an anther are epidermis and tapetum.

The anther wall is made up of four layers: the epidermis, endothecium, middle layers, and tapetum. The epidermis is the outermost layer and is made up of a single layer of cells. The endothecium is the layer just inside the epidermis and is made up of thickened cells. The middle layers are located between the endothecium and tapetum, and they are made up of loosely arranged cells. The tapetum is the innermost layer and is made up of cells that surround the sporogenous tissue.

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.