FIGURE 3.

Lenticels found in one-year-old sprigs (A) and in three-year-old sprigs (B). The lenticels show a higher number of cell layers above the lenticular phellogen that propel the epidermis upwards causing it to fracture [arrowhead in (A)]. In three-year-old sprigs (B), the lenticular phellogen localized in much larger areas due to anticlinal divisions and continuous activity during sprig development. The walls of the lenticular cells emit less autofluorescence than cork cells when excited with UV light, indicative of distinct cell wall composition. (C) Nuclei from younger lenticels are whole and round, while from older lenticels are misshapen and fragmented at the innermost regions of the lenticels (D). (E) At the outermost regions of the lenticels nuclei are highly fragmented as cells are differentiating with portions of chromatin protruding from a central less condensed chromatin mass. DNA was counterstained with DAPI. Bars in (A,B) = 20 μm and in (C–E) = 10 μm. Ep, epidermis; Lph, lenticular phellogen; C, cork cells; Lc, lenticular cells.