Figure 1. Symplastic connectivity between the outer tissues and the primordia is regulated during lateral root development. A symplastic fluorescent dye (green; FDA), generated from CFDA applied exogenously, moved freely through cell layers in non-lateral root regions and into stage I–II primordia (A-B). Movement was blocked after transition from stage III to IV primordia (C-E) and restored just before emergence (F). Images in the brightfield channel (superimposed) were used to distinguish the lateral root primordia (LRP, arrowed in B-F). Scale bars: 20 µm.