Question

When pollen grain is shed at 3 celled stage .name the cells it contains

Answer 1

Pollen grain contains the male gametes that must reach the female ovum to produce a seed.When a pollen grain is shed it may have two cells or three cells. When it is shed in the three celled stage it has the following cells:

One vegetative cell and two male gametes. 

These are released into the style which gets transported into the ovary of the flower to bring about fertilisation.