The correct answer is Option (4) → Microspores
Atypical stamen has two parts – the long and slender stalk called the filament, and the terminal generally bilobed structure called the anther. The anther is a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe.
The microsporangia develop further and become pollen sacs. They extend longitudinally all through the length of an anther and are packed with pollen grains. In a transverse section, a typical microsporangium appears near circular in outline. It is generally surrounded by four wall layers– the 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.
The sporogenous tissue, which is located at the center of each microsporangium, gives rise to microspores. Microspores are the precursor cells that develop into pollen grains. During the process of microsporogenesis, the cells of the sporogenous tissue undergo meiosis, a type of cell division that results in the formation of haploid microspores. These microspores are arranged in clusters called microspore tetrads. As the anthers mature and dehydrate, the microspores dissociate from each other and develop into individual pollen grains. Therefore, the sporogenous tissue plays a crucial role in the production of microspores, which ultimately give rise to pollen grains. |
