Cactus / Degrafting

I degraft cactus with 3 methods.
1. Normal one, removing stock completely
2. Remained a short vascular bandle of the stock
Roots come from the vascular bandle initially but own roots of the plant
are back up later.
3. Remained a short stock
Roots come from the short stock, no roots come out from the plant never
except pereskiopsis short stock.
The photo is the degrafting with a short stock. The plant is Echinocactus horizontalonis, 12 cm diameter, sowed seeds on 02/09/2005 and grafted young seedlings.