Question

Above is the diagram of the T.S. of the anther. Identify the parts labeled as A, B, and C.
(a) A- Connective tissue, B- Pollen grain, C- Stomium
(b) A- Endothecium, B- Connective tissue, C- Pollen grain
(c) A- Pollen grain, B- Connective tissue, C-Endothecium
(d) A- Endothecium, B- Pollen grain, C- Connective tissue

Answer 1

Hint: Stamen is the male reproductive organ. It consists of two parts- another and filament. The filament is the stalk to which anther is attached. In another, the development of male gamete carriers occurs.

Complete answer:
The anther is bilobed with two pollen sacs each called microsporangia. In the wall of a mature anther, the epidermis is the outermost layer, followed by a single layer of endothelium, then one to the three-layered thick middle layer, and innermost single-layered tapetum.
A strand of connective tissue extends from the filament to the anther. It is present between the two lobes and thus maintains their connectivity. In the diagram, it is labeled as ‘A’.
The two pollen sacs in each lobe contain pollen grains which are represented by ‘B’.
Stomium is a layer of thin-walled epidermal cells that are present at the line of dehiscence. Thus, when the time comes for the dispersal of pollen grains, and anther breaks and splits at this line of dehiscence only. It is represented by ‘C’.

Additional Information: -Tapetum consists of cells with large nuclei and dense cytoplasm.
-The main function of tapetum is the production and transport of enzymes, hormones, and nutrients, necessary for pollen development.
-The process of production of haploid pollen grains is known as microsporogenesis. A diploid microspore mother cell undergoes meiosis to release a tetrad of pollen grains.
-These four pollen grains are united by callose. Tapetum secretes callase, an enzyme to separate microspores or pollens from tetrad into individual cells.
So, the correct answer is ‘ A- Connective tissue, B- Pollen grain, C- Stomium.’

Note: - Pollen grains are the male gametophyte which means they are the carriers of the male gamete.
- The wall of pollen grain contains an outer exine and inner intine.
- The exine is immune to microbial and chemical disintegration due to the presence of sporopollenin.
- Germ pore is an aperture on the pollen’s wall where sporopollenin is absent and aids the release of the male gamete.