Are you using CO2 (either DIY-yeast or pressurized) in your tank? Do you use Excel? I don't have this plant, so I can't give you a sure answer. But my first impression is no, they are not pearling. The bubbles are too big. By any chance did you do a water change before this picture was taken? Water changes sometimes create "false pearling" as the turbulence of the newly-added water can oxygenate the tank enough to create "false pearls" for a few hours.