The process of formation of microspore or pollengrain from microspore mother cell through meiosis is known as microsporegenis .
During this process the cells of the sporogenous tissue divide with the growth of anther and increase their number .
Ultimately they are transformed into microspore mother cell or pollen mother cell .
The primary mother cell are diploid i.e. they have two sets of chromosomes .
The primary mother cell under goes meiosis to produce tetrads of haploid microspore or pollengrains which later separates from each other .
The entire pollengrain is unicellular haploid and globular in structure .
Each microspore contains a nucleus at the center and the cytoplasm .
The entire pollengrain is surrounded by two layered wall are
1- Exine - It is the outer layer of microspore which is thick round and made up of a complex substance sporo pollen.
2- Intin - It is the inner layer which is uniformly thin smooth and made up of cellulose and pectin .
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