Fig. 4

Activity shoot bud (ASB) development in the second node. a–b ASB primordium located at the center of the developing and matured bract. c–e ASB apex development when the matured bract was peeled off. f ASB structure when the young apex of ASB was peeled off again and a new growth point (arrow). g–i are the respective SEM images for (d–f); in these images, the trifoliolate apex can be seen to exhibited a high developmental activity. The scale bar is 50 μm in (a-d) 100 μm in (e–f), and 20 μm in (g–i)