Fig. 7. WUS and PIN1 are functionally required for efficient shoot meristem induction. (A) Bar graph showing average numbers of shoots formed after 4 weeks of induction on SIM from 2 cm callus explants in wild type (Ler) versus wus-1, and in a separate experiment, Ler versus pin1-4.(B) Bar graph showing number of shoot promeristems, marked by pPIN1::PIN1-GFP and pSTM::STM-VENUS coexpression, in Ler versus wus-1. (C) pPIN1::PIN1-GFP (green) and pSTM::STM-VENUS (blue) expression in a shoot promeristem initiated in the wus-1 mutant. Chlorophyll autofluorescence is in red. (D) 24 hours later, the shoot promeristem initiated early primordia (P₁ and P₂) marked by pPIN1::PIN1-GFP, while pSTM::STM-VENUS marked the presumptive shoot meristem. (E) 48 hours later, primordia (P₁ and P₂) have further developed and two early primordia initials (I₁ and I₂) have formed near the apex of the meristem. Scale bars: 50 µm.