Figure 1

Nuclear division and morphogenesis during early stages of pathogenic germination. Spores of strain H1-13 were germinated on a slide in pea extract: (a) resting spore; (b) first nuclear division (75–90 min); (c) germ tube formation (90–120 min); (d,e) germ tube elongation and second nuclear division (150–180 min); (f) appressorium formation and third nuclear division (4–6 h, arrow points to the septum between the germ tube and appressorium); (g, h) formation of the second germ tube and appressorium (7–9 h). Pictures represent sequence events and are projections of optical sections. The scale bar is 5 μm.