The immature stage of an anther is characterized by a parenchymatous tissue group enclosed by a single-layered epidermis. Anthers are typically dithecous (with two lobes) and tetrasporangiate. A monothecous anther holds two pollen sacs, while a dithecous anther has four, making it tetrasporangiate. Heterogeneity in differentiation occurs when certain hypodermal cells undergo transformation into archesporial cells.
The archesporial cell undergoes division, giving rise to an inner sporogenous cell and an outer primary parietal cell. The sporogenous cell forms the sporogenous tissue, where each cell has the potential to produce a microspore tetrad. Meanwhile, the primary parietal cell divides to create the layers of the anther wall.
The mature anther’s wall comprises four layers: the outermost epidermis, composed of flattened cells; the sub-epidermal endothecium with radially elongated cells and fibrous thickenings; the middle layer with thin-walled cells, which may disintegrate in maturity; and the innermost tapetum, a nutritive layer surrounding the sporogenous tissue.
