Plant receptacle contains oat mix (6)
I believe the answer is:
potato
'plant' is the definition.
The answer is an example.
'receptacle contains oat mix' is the wordplay.
'receptacle' becomes 'pto' (I can't justify this - if you can you should believe this answer much more).
'contains' indicates putting letters inside.
'mix' is an anagram indicator.
'oat' is an anagram of 'ota'.
'pto' going around 'ota' is 'POTATO'.
Can you help me to learn more?
(Other definitions for potato that I've seen before include "A plant; hole in sock (colloq.)" , "The vegetable is just too pat" , "Root crop" , "Edible tuber; hole in stocking (colloq.)" , "Root vegetable" .)