Introduction
Sporogenous is the production of spores in biology. The term is also used to refer to the process of reproduction via spores. Reproductive spores were found to be formed in eukaryotic organisms, such as plants, algae, and fungi during their normal reproductive life cycle.
Reproduction spores are generally the result of cell division, most commonly meiosis example in plant sporophytes. Sport meiosis is needed to complete the sexual life cycle of the organisms using it. In some cases, sporogenous occurs via mitosis example in some fungi and algae. Mitotic sporogenesis is a form of asexual reproduction. In the case of dormant spores in eukaryotes, sporogenesis often occurs as a result of fertilization or karyogamy forming a diploid spore equivalent to a zygote. Therefore, zygospores are the result of sexual reproduction.
Sporogenous Tissue
The spore-producing cell that is found in the young anther of flowering plants is called sporogenous tissue. Sporogenous tissues are a group of homogenous cells that occupy the central position of a microsporangium. Microsporangium is a circular structure present in the anther lobes, which further develops into pollen sacs.
Formation of Sporogenous Tissue
The anther consists of actively dividing cells called archesporial cells. The archesporial cells divide through a periclinal division to give rise to a parietal layer and a sporogenous layer. The cells of the sporogenous layer further divide to give rise to diploid sporogenous cells.
Sporogenesis
These are located at the Centre of each microsporangium in a young anther. With the development of the anther, the sporogenous cells undergo meiotic division to form microspore tetrads. Each sporogenous cell is known as a pollen mother cell or microspore mother cell. This process by which a microspore is formed from the pollen mother cell is known as microsporogenesis. The microspores are arranged in the form of a tetrad. As the anther matures it dehydrates and the microspores dissociate from each other and develop into a pollen grain.
Microsporangium
Microsporangium is a structure in the plant’s male reproductive organ where the development of pollen takes place. Male gametophytes of plants develop and grow in the anther of the plant. Microsporangium is a part of the plant where pollen and microspores are produced.
Microspore
Microspores are the tiny spores that form male gametophytes which grow to form sperm cells and sperm cells combine with the egg cells to form a zygote.
Microsporogenesis
The process of formation of haploid microspores from a pollen mother through meiosis is called microsporogenesis. There is a mass of sporogenous tissue at the centre of each microsporangium in the young anther of the plant. When the anther develops, the sporogenous cells found in the sporogenous tissue make microspore tetrads through meiotic division. Each cell is called a microspore or pollen mother cell. The microspores arrange themselves in the form of a tetrad. When the anther matures and dehydration occurs, the microspores detach from each and form fully grown pollen grains.
Pollen Grains
The pollen grains represent the male gametophyte. The matured pollen grain contains two cells: a generative cell and a pollen tube cell. The generative cell is present within the larger pollen tube cell. The tube cells form the pollen tube on germination. The generative cell migrates into the ovary through the pollen tube. Inside the pollen tube, the generative cell divides into two gametes or sperms. The anther matures and releases the pollen grains.
Anther
It is a bilobed and dioecious structure. In the transverse section, it is a tetragonal structure consisting of four microsporangia located at the corners, two in each lobe. Microsporangia develops further into pollen sacs. pollen sacs contain pollen grins.
Structure of Microsporangium
-
Microsporangium is circular in outline
-
It is surrounded by the four wall layers: the epidermis, endothecium, middle layers, and the tapetum
-
The outer three wall layers are protective in function and help in the dehiscence of anther to release the pollen
-
The innermost wall layer that is tapetum provides nourishment to the developing pollen grains
-
A sporogenous tissue occupies the centre of each microsporangium
Functions of Sporogenous Tissue
-
The sporogenous tissues are located in the microsporangium of the young anther
-
The sporogenous cell undergoes meiotic division to form the microspore tetrads
-
The sporogenous cell is also called microspore mother cells
-
The microspores are arranged in the tetrad
-
On the maturation of anther the microspore dissociates to develop pollen grain
Conclusion
The function of sporogenous tissues is the production of pollen grains. The sporogenous tissues are located in the microsporangium of the young anther. The sporogenous cells undergo meiotic division to form the microspore tetrad. Each sporogenous cell is known as a pollen mother cell or microspore mother cell. This process by which a microspore is formed from the pollen mother cell is known as microsporogenesis.