On one's own in plant, bottling nitrogen (5)
I believe the answer is:
alone
'on one's own' is the definition.
(I've seen this before)
'plant bottling nitrogen' is the wordplay.
'plant' becomes 'aloe' (aloe is a kind of plant).
'bottling' is an insertion indicator (bottling is a kind of containing).
'nitrogen' becomes 'n' ('N' can be a synonym of 'nitrogen').
'aloe' placed around 'n' is 'ALONE'.
'in' is the link.
(Other definitions for alone that I've seen before include "Without anybody or anything else" , "Note of charges" , "without another" , "without partner?" , "Isolated; exclusively" .)