Sunday, 12 July 2020

Types of Tetrad (arrangement of pollen grain) - Class 12, Chap 2, Lecture 5

Sexual Reproduction in flowering Plants
Types Of Tetrad:

All the four microspores formed from the microspore/pollen mother cell ( MMC/PMC ), initially remain attached together with the help of callose layer, so the group of microspores formed is called Tetrad. This arrangement of microspores is different for different plant types, which is given below:-
1. Tetrahedral tetrad - Four microspores are arranged in a tetrahedral form. e.g., - Dicotyledon.
2. Isobilateral tetrad - Four pollen grain/microspores are arranged laterally . e.g., - Monocots.
3. Decussate tetrad - Out of four microspores two microspores are arranged at the right angle of the other microspores. e.g., - Dicotyledon.
4. T-Shaped tetrad - Out of four microspore two microspore lies longitudinally and other two lies transversally . e.g., - Dicotyledon.
5. Linear tetrad - When all pollen grains are arranged in a linear order, then the formed tetrad is linear tetrad. e.g., Monocots.

* Most common type of tetrad is Tetrahedral Tetrad.

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