Sunday, 12 July 2020

Types of Tapetum - CLASS 12 , Chap-2 , Lec-3

                                            Sexual Reproduction in Flowering Plants
                                
 Types of Tapetum

Tapetum is of following type:

1.Amoeboid or Periplasmodial or Invasive Tapetum
Such type of tapetum is mostly found in primitive type of angiospermic plants. This tapetum initially absorb all nutrients from the middle layer and middle layer degenerates immediately. Now the tapetum store all food material and later on it convert all these food material into special material which is called as protoplast bodies.
                       Now , the tapetum finally degenerates and release the protoplast bodies in the pollen sac, here it is known as periplasmodium and supply nutrition to the developing microspore.

2.Secretory Tapetum or, Glandular tapetum  
This type of tapetum is well developed and stable . This type of tapetum do not absorb all nutrients from middle layer immediately. This tapetum absorb nutrients  and transfer it to the pollen sec. Tapetum convert the absorbed nutrients in a special material called it proubisch body , making it permeable across the cell membrane. Just before the maturity of microspore tapetum integrate sporopollenin and proubisch body now this material is called Ubisch body and tapetum degenerates to release ubisch body in microsporangia. Now in microsporangia sporopollenin form the exine of pollen grain.

Objective type question-
1. which of the following is responsible for formation of Ubisch bodies?
a). Endothecium     b). Embryo sac
d). Tapetum             e). Pollen grain
2. The developed type of tapetum is-
a). Periplasmodial tapetum   b). Glandular tapetum
c). Both                                  d). None
3. Sporopollenin is integrated with -
a). Protoplast                  b). Ubisch body
c). Pro-ubisch body         d). None

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