Stop to take stock (4)
I believe the answer is:
stem
I believe this clue is a double definition.
'stop' is the first definition.
(stemming is a kind of stopping)
'stock' is the second definition.
(thesaurus)
'to take' acts as a link.
(Other definitions for stem that I've seen before include "Vertical part of flower or drinking glass" , "Main part of noun or verb" , "Main central part as of plant or glass" , "It supports a plant" , "Flower's stick" .)