Sexual reproduction in flowering plants (New syllabus chapter 1 / old syllabus Chapter 2)
Microsporogenesis|reproduction in flowering plants|short notes| NCERT| standard 12| Biology
Note 4
Microsporogenesis
Definition: "The process of formation of microspores from a Pollen Mother cell/ Microspore Mother Cell through meiosis is called as microsporogenesis."
- as the flower grows, Anther develops or matures.
- The sporogenous tissue comes into action : these cells directly enters microsporogenesis
-The cells of sporogenous tissue undergo meiotic division.
- each cell of sporogenous tissue has capability to convert into pollen mother cell / microspore mother cell
-Each cell develops a microspore tetrad
-Microspore Tetrad: 4 microspores(not fully developed) attached with each other with a substance called Calose.
-Then, Anther further matures - looses water (dehydrate)
- Microspore dissociate from each other by the action of enzyme Calase (secreted by cells of tapetum)
- further development of microspore - addition of sporopollenin (forms exine) and development of cellulose and pectine (forms intine)
- this generates pollen grains
- pollen grains dispersion with dehiscence of anther.
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| Flowchart of microsporogenesis |
Q: How many pollen grain are produced from one single cell of sporogenous tissue?
A: 1 Cell of sporogenous tissue ––—> 1 Pollen Mother cell / Microspore Mother Cell ——> meiotic division ——> 1 microspore tetrad ——> maturation ——> 4 pollen grains
Q: What is the Ploidy of each cell(microspre) of the tetrad ?
A: haploid (because diploid sporogenous tissue cell undergoes meiotic division- hence produces 4 haploid cells)
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