Hello Alice. I experimented with gene gun transformation in prickly pear cactus. Stable transformation rate is very low (less than 1 percent in some species). Try experimenting with different bead sizes and pressures to get the right spread and density to increase your chances (use cross sections to see how far and dense the bead penetration is). Also consider using an RFP instead of a GFP as your reviewers will inevitably ask how you know it's not auto-fluorescence. General rule is if you still have fluorescence after two weeks it's stable transformation. This protocol is like playing cards at the casino, the more hands you play the better chances you have at winning! Good luck!