Loss of water it's said in vegetables (5)
I believe the answer is:
leeks
'vegetables' is the definition.
(leek is a kind of vegetable)
'loss of water it's said' is the wordplay.
I cannot quite understand how this works, but
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found in the answer.
The remaining letters 'leks' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'in' acts as a link.
Can you help me to learn more?
(Other definitions for leeks that I've seen before include "Welsh vegetables?" , "Scallions" , "Welsh emblems" , "Vichyssoise ingredient" , "Vegetables - keels (anag)" .)