Fig 4. Histological analysis of shoot apex and leaf primordial tissues in non- and nematode-infected (Litylenchus crenatae subsp. mccannii) buds of beech (Fagus grandifolia).

Bright-field photomicrographs of bud scale cross-sections stained with a mixture of toluidine blue and basic fuchsin are shown. (A-B) Beech leaf shoot apex and leaf primordial cells marking nematodes within these tissues (arrows). (C-E) Examples of leaf primordial developing in buds infected with nematodes (arrows). Note the presence of different number of disorganized and abnormal cell layers (n > 6) in each leaf primordia. (F) Cross-section of leaf primordia from a non-infected bud showing six distinct layers of highly organized cells. Scale bars: 50 μm.