Yes, some can. I have had success rooting the following in water:

P. caerulea
P. "Pura Vida Red"
p. x Belotii
p. serrato-digitata
p. amethystina "Minas Gerais"

I'm sure others would do fine as well

Good Luck
-Zem

I root a variety of passies in water. I do use a seed mat to provide bottom heat and an air stone to keep the water circulating. The aeration isn't really necessary but you don't need to change the water often if you use it.
Karyn