What is a Pollen Mother Cell?

A diploid cell called the pollen mother cell goes through meiosis and produces four haploid microspores, also referred to as male gametophytes. Microsporogenesis is the process by which microspores develop from a microspore mother cell. Pollen mother cells (PMCs) is a crucial early step in plant sexual reproduction when the groundwork is laid for the development of male gametes.

As long as the flower buds are underground, pollen mother cells (PMCs) are generated within the anthers. Young PMCs have an isodiametric shape and exhibit a straightforward ultrastructure in their cytoplasm. As meiosis progresses, PMCs lose their isodiametric shape and start to swell more and more. Before and during meiosis, no callose is deposited around PMCs or microspores.

After cytokinesis, which results in the creation of a cell plate that expands centrifugally and lacks callose as well, kyokinesis occurs. The male gametophyte that results from the generative cell’s division into two sperm is known as the tricellular pollen. Throughout their development, the sporophytic cells of the anther form various layers around the male reproductive cells.

Formation of Microspores

Inside the anther, pollen mother cells give rise to microspores. Microsporogenesis involves the division of a pollen mother cell during meiosis to produce microspores. To create a microspore tetrad, sporogenous tissues cells divide by meiosis. The microspore separates and transforms into pollen grains when the anther ages and dehydrates. The male gametophytes are represented by the pollen grain. Each pollen grain has a two-layered wall: an inner wall consisting of cellulose and pectin and an exterior wall made of sporopollenin.

Microspores

A microspore is a cell that reproduces. Without fusing with any other reproductive cells, the microspore has the capacity to produce new individuals. These are the spores that the sporophytes create. Microspores are produced by flowering plants within their anther pollen sacs.

Pollen sacs

A pollen sac is a structure found in seed plants that contains pollen. Each anther of angiosperms has four pollen sacs, which also house the mother cells for microspores. The microsporophyll, which is abundant with pollen sacs in gymnosperms, is what gives rise to the male cone.

Pollen grains

A pollen grain is a small structure that houses an androecium, which is a flower’s male reproductive system. The tube cell and cytoplasm are located inside the pollen particle. The generative cell releases the sperm nuclei as the tube cell transforms into a pollen tube.

Ploidy level of Pollen Mother Cell

The ploidy level indicates how many chromosomes are found in a cell or organism’s DNA. The origin of each portion affects its ploidy level. It comes in two primary categories: A cell with only one set of chromosomes is said to be haploid, and a cell with two sets of chromosomes is said to be diploid. Other than this one more condition is also present in some cases which are known as Polyploidy. When an organism has more than two sets of chromosomes, it is said to be polyploid. It has a significant impact on generating individual variation. A Pollen mother cell often referred to as a meiocyte, goes through meiotic division and generates female gametes. So the ploidy of pollen mother cell is 2n.

Interesting Facts

• Plants’ pollen mother cells, also known as microsporocytes, are diploid cells that divide during meiosis. One pollen mother cell may produce four haploid microspores. Mother cells develop inside the pollen sacs of the anthers of flowering plants. They create microspores, which undergo mitosis to become pollen grains.

• Microsporogenesis is the process of meiotic or reduction division that results in the development of microspores inside a pollen sac.

• The microsporangium is a type of sporangial structure that houses microspores, the pollen sacs that give rise to male gametes in angiosperms. A microsporangium typically has four layers of wall around it and has a circular shape in the transverse section. The epidermis only has one layer, which is the outermost.

Important Questions

1. Is a pollen mother cell a gamete?

Ans: In many species, the microgametophyte does not reach maturity until after pollen germination. A pollen mother cell give rise to four gametes during microsporogenesis. Pollen mother cell undergoes meiosis resulting in the generation of four haploid cells.

2. Where are pollen cells found?

Ans: Pollen cell is made in the anthers of the stamen. The anther is tetrasporangiate having four pollen sacs. Pollen mother cells undergo meiotic division in the anther, resulting in the production of four microspores per cell.

Key Features

• Microsporogenesis is the process of producing microspores through the meiotic division of microspore mother cells. Megasporogenesis is the process by which megaspores are organised from the mother cell of the megaspore.

• The mother cell of the microspore is a diploid cell. To produce the microspore tetrad, it goes through two sequential meiotic divisions. Chromosome count is cut in half during meiosis. The four microspores that result are hence haploid in nature.

• Sporopollenin is found in the pollen grain’s exine or outer wall. It is one of the known chemical compounds with the highest resistance. It shields pollen grains from environmental elements like heat, acid, alkali, etc.