Naturally they support discussion on board (6)
I believe the answer is:
stalks
'naturally they support' is the definition.
The definition suggests an adverb but the answer is not.
'discussion on board' is the wordplay.
'discussion' becomes 'talk' (talk is a kind of discussion).
'on' is an insertion indicator.
'board' becomes 'ss' (I've seen this in other clues).
'talk' going inside 'ss' is 'STALKS'.
Can you help me to learn more?
(Other definitions for stalks that I've seen before include "Follows stealthily with evil intent" , "Hunts" , "Shadows with plant stems" , "Tracks or pursues stealthily" , "They support plants" .)