Go along with law restricting fungal growth (6)
I believe the answer is:
accept
'go along with' is the definition.
(thesaurus)
'law restricting fungal growth' is the wordplay.
'law' becomes 'act' (I've seen this before).
'restricting' is an insertion indicator.
'fungal growth' becomes 'cep'.
'act' placed around 'cep' is 'ACCEPT'.
(Other definitions for accept that I've seen before include "Concede" , "Receive willingly or take as true" , "Say yes > to trust" , "Consider or hold as true" , "Receive something proffered" .)