Two weeks after inoculation, the meristematic
nodules, which had become 1 to 3 mm in diameter and a
little darker green, were observed on the abaxial side as
well as on the cut ends of the leaf segments (Figure 1B).
Simultaneously, new nodules were formed on the surface
of old nodules. At three weeks after inoculation, the
nodules were observed both above and below the
medium surface, and the original morphology of a leaf
segment was almost completely lost (Figure 1C). We
observed complete nodules on a leaf segment at three
weeks by scanning electron microscopy (Figure 1D).
Several protuberances, possibly daughter nodules were
observed on the surface of the nodule (Figure 1D,
arrows).