One appeals, putting pressure on landlord (7)
I believe the answer is:
pleaser
'one appeals' is the definition.
(someone who appeals to people or pleases them)
'pressure on landlord' is the wordplay.
'pressure' becomes 'p' (scientific abbreviation).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'landlord' becomes 'leaser' (I've seen this in another clue).
'p'+'leaser'='PLEASER'
'putting' is the link.
(Other definitions for pleaser that I've seen before include "someone to whom gratitude is due" , "One satisfying" , "One trying to make others happy" .)