Figs. 3.14-3.18. Fig. 3.14. Transverse section of a portion of the ligno-suberized boundary zone and new periderm (NP) adjacent to peach bark tissue colonized by Leucostoma persoonii (top) showing altered phellem cell shape (arrows). Fig. 3.15. Longitudinal section through pith (P), xylem (X), and bark (B) (tissues are between opposite oriented arrows), sampled seven days after inoculation with Leucostoma persoonii, showing four polysaccharide-rich reaction zones (large arrows). Colonization from left to right had proceeded in the bark through the first zone and was almost to the second. Fig. 3.16. Fluorescence illumination of the longitudinal margin of a 56-day-old quiescent canker on peach caused by Leucostoma cincta. The section has been treated with phloroglucinol+HCl and shows a complete intact necrophylactic periderm (NP) contiguous with the original exophylactic periderm (EP). Note aggregation of fungus mycelium (arrow) exhibiting weak autofluorescence. Fig. 3.17. Transverse section of a 14-day-old mechanical wound on peach bark, treated with phloroglucinol+HCl, and showing the nonsuberized ventral region (between large arrows) of new callus (CL). The residual autofluorescence is due to suberin in the outer cell layers of the callus (small arrows). Fig. 3.18. Longitudinal section of a 14-day-old mechanical wound on peach bark inoculated with Botryosphaeria dothidea, showing hyphae colonizing the ventral region of the callus (CL) and the xylem surface. For all figures, bar = 10 m except where indicated.