Question

During microsporogenesis, meiosis occurs in
A. Endothecium
B. Microspore mother cell
C. Microspore tetrads
D. Pollen grains

Answer 1

Hint:- Male reproductive organs in flowering plants are called as androecium and their unit is called the stamen. Stamen is also known as microsporophyll. A typical stamen is differentiated into two parts- a long thin structure is called a filament. Stamen is attached to thalamus or petal by the proximal end of the filament. At the distal end of the filament, a swollen microspore bearing structure is present which is called the anther.

Complete Answer:-In the initial stage, the anther appears as an outgrowth like structure. This outgrowth is spherical or oval. This oval-shaped structure is just a mass of meristematic cells which is surrounded by a single-celled thick outer layer. This layer is known as the epidermis. These epidermal cells form the wall of the sporangium. Simultaneously a group of cells which are located just below the epidermis in vertical rows of the hypodermal region at the four corners become large. These cells are called archesporial cells.
Archesporial cells undergo periclinal division (parallel division) and form primary parietal cells and primary sporogenous cells. Primary parietal cells undergo further periclinal and anticlinal divisions to form a series of three to five layers making the walls of the anther. The primary sporogenous cells divide by mitotic divisions to form sporogenous cells or sporogenous tissue and later sporogenous cells differentiate into microspore mother cells. Each microspore mother cell divides to form four haploid microspores of pollen grains by meiotic division. This process is called microsporogenesis.

Thus the correct answer is Microspore mother cell, option (B)

Note:- At the initial stage, all four microspores are attached with the help of callose layer. This group of microspores is called a tetrad. In flowering plants, microspore or pollen grain is considered as the first cell of male gametophytic generation. Each cell of sporogenous tissue is capable of giving rise to microspore tetrad. Each one is a potential microspore mother cell.