Spring in the base (4)
I believe the answer is:
stem
I believe this is a double definition.
'spring' is the first definition.
(thesaurus)
'base' is the second definition.
(thesaurus)
'in the' is the link.
(Other definitions for stem that I've seen before include "supporter of flag, for example" , "Dam" , "Flower's stick" , "Staunch - support" , "part of pipe" .)