Germ cell (5)
I believe the answer is:
'germ cell' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for spore that I've seen before include "Tiny reproductive cell of fungus or fern" , "Reproductive body produced by fungi" , "Fungal cell" , "Ropes (anag.)" , "Asexual reproductive body" .)