Antigone nonetheless chopped up a plant (7)
I believe the answer is:
gentian
'plant' is the definition.
(gentian is a kind of plant)
'antigone nonetheless chopped up a' is the wordplay.
'antigone nonetheless' becomes 'gent' (I can't justify this - if you can you should give a lot more credence to this answer).
'chopped' means to remove the last letter.
'up' becomes 'is' (I've seen this in other clues).
'a' becomes 'an'.
'is' with its last letter taken off is 'i'.
'gent'+'i'+'an'='GENTIAN'
Can you help me to learn more?
(Other definitions for gentian that I've seen before include "Violet's partner" , "Small deep blue flower" , "Mountain plant with blue bell-like flowers" , "Antigen in vivid blue flower" , "Flower - antigen (anag)" .)