Why won't the pollen gain gets degraded in spite of the presence of germpores on the sporopollenin containg exine layer???????

Dear student, 

I think you have mistaken the concept, but I'm glad that you are curious enough to ask this .Hope my answer helps.

 

If u give a reading to NCERT BIO CLASS XII, CH -2, Reproduction in flowering plants, the line from Pg. 23 reads that pollen grains have two layers: Outer Exine (made up of sporopollenin )

And its this sporopollenin which is highly resistant organic material , not the entire pollen grain. Pollen grain may degrade in many cases. Yes , it is definite that these resistant and inert properties of pollen grain imparts protective function to the pollen grains to a great extent.

      But it is not at all necessary that the pollen grain would not degrade at all even if exine is present. Mainly germpores are meant for gaseous and water exchange functions and the pore is really very minute for excess moisture to get through the pollen ,thereby keeping it dry and free from micro-organisms and decay.