Refer to ok vine production (6)
I believe the answer is:
invoke
'refer to' is the definition.
(invoking is a kind of refering to)
'ok vine production' is the wordplay.
'production' indicates an anagram.
'ok'+'vine'='okvine'
'okvine' anagrammed gives 'INVOKE'.
(Other definitions for invoke that I've seen before include "Call upon in prayer, perhaps for protection" , "Call on or appeal to" , "Summon into action or bring into existence" , "Call upon in prayer, as for assistance" , "Call on a god to do something" .)