Ace donated tropical plant (5)
I believe the answer is:
agave
'tropical plant' is the definition.
(plant grown in tropical regions)
'ace donated' is the wordplay.
'ace' becomes 'a' (abbreviation).
'donated' becomes 'gave' (give can mean to donate).
'a'+'gave'='AGAVE'
(Other definitions for agave that I've seen before include "Plant, source of sisal" , "A cactus" , "Spiky succulent" , "native growing up in tropical America" , "source of tequila" .)