Assume Daniel is working in the plant (9)
I believe the answer is:
dandelion
'plant' is the definition.
(dandelion is a kind of plant)
'assume daniel is working in' is the wordplay.
'assume' becomes 'don' (I've seen this in another clue).
'is working' indicates anagramming the letters.
'in' indicates putting letters inside.
'daniel' is an anagram of 'andeli'.
'don' placed around 'andeli' is 'DANDELION'.
'the' acts as a link.
(Other definitions for dandelion that I've seen before include "Yellow weed" , "Wild plant with "clock"" , "Flower with a "clock"" , "Common yellow-flowered weed" , "salad plant" .)