The germ pores in the pollen grain are the regions
which lack sporopollenin
Germ pore is the small pore in the outer wall (exine) of the pollen grains. These are the regions which lack sporopollenin (a substance found in outer layer which is resistant to high temperature and strong acids and alkali). These germ pores help in the formation of the pollen tube and the releases male gametes during fertilisation.