Sections of young developing leaves within nematode-infected (<i>Litylenchus crenatae</i> subsp. <i>mccannii</i>) beech buds (<i>Fagus grandifolia</i>) with altered interveinal leaf cell proliferation.

Morphological cell rearrangements of interveinal leaf cross-sections. (A) Representative section of control leaf interveinal areas with the typical six layers of cells. (B-D) Three interveinal areas of the same leaf infected by nematodes showing a variable and prominent increase in the number of cells layers. Outline drawings of some representative interveinal areas highlighting this upsurge in cell division associated with nematodes (B’-C’) compared to the control (A’). (E) Veinal areas of the same nematode-infected leaf displayed different levels of ectopic cell proliferation. (F) Differential cell proliferation within the same interveinal leaf area dissected from a nematode-infected bud. Scale bars: 20 μm.