Development Of Male Gametophyte

Development Of Male Gametophyte :-

Male Gametophyte development Happen in 2 main Step 

1st = Pre-pollination :- 

All the changes or development happens before pollination
* In 70% Dicot, Microspore Divide into 2 Parts
* In Rest 30% Dicot, Microspore Divide into 3 Cell Before Pollination

NOTE :- 

When Microspore Start germination found Inside Microsporangium Called Precoceous

2nd = Post-Pollination :-

All the Changes or events Happens After & During pollination

@ Microspore :- 

is a firstly developed male gametophyte

@ Character :-

 It have Dense cytoplasm , lot's of lubish body & large vacoule

@ Development :- 

- Vacoule Became Large pushes nucleus toward bottom side of microspore
- Nucleus Divide by unequal Division , Cells attach to wall form lense shape
- After Some time Cellulose Cementing substance Deposit outside germinating cell get apart & Independent cell form generative cell
- Now, This cell called Pollen grain (Which are Partially germinated)
- Now Pollen Grain released at in 2 cell or may be 3 cell from anther
- After That Released 2 or 3 celled pollen grain react to outer surface of stigma by agency of water, wind or animal etc called Pollination
- Development of male gametophyte on stigma Involve steps are :-
i) Absorption of Water by pollen grain
ii) Swelling of pollen grain with in few minute
iii) Releasing of Wall recognition Factor

NOTE :-

 These Factor Decide Wheather pollen grain germinate or not on that particular stigma
iv) After Mutual Recognition Tube cell enlarge & intine Come out in form of pollen grain after rupturing Exine
v) Pollen tube grow within cell of stigma in transmitting tissue of style
vi) Pollen tube secrete pactenase & Hydrolytic Enzyme , These enzyme produce entry of pollen tube also absorb nourishment
vii) Tube cell & germinate cell move at tip of pollen tube with regular cellulose deposite in the tube
viii) Germinate Cell Divide Form male gamete
ix ) All back part became Non-functional , due to deposition of of cellulose
x) Tube cell degenerate before fertilization, they function as give nourishment to sperm cell