Figure 6.

Loss of meristem determinacy in spikelets of eary ears and phyllodied tassels of S. reilianum-infected maize cv Gaspe Flint. A, Longitudinal section of an eary spikelet showing the development of new inflorescences in the upper and lower florets. Bar = 1 mm. B, Magnification of the part boxed in A showing the development of an inflorescence meristem instead of a spikelet meristem. Bar = 200 μm. C, Longitudinal section of an eary spikelet showing massive hyphal growth of S. reilianum (black area; white star) in the newly formed inflorescence. Arrows highlight noncolonized vegetative tissues. Fungal hyphae were stained with Chlorazole Black E. Bar = 500 μm. D, Tassel inflorescence of a healthy plant showing the development of a branched inflorescence. Bar = 500 μm. E, Tassel-like inflorescence formed in the center of an infected phyllodied tassel floret. Bar = 500 μm. F, Longitudinal section of a healthy tassel inflorescence showing the development of spikelet pairs (arrows). Bar = 500 μm. G, Longitudinal section of a newly formed tassel-like inflorescence from a phyllodied tassel floret of an infected plant showing the development of spikelet pairs (arrows). Branches of the newly formed tassel-like inflorescence are enclosed within leafy structures (star). Bar = 500 μm. H, Magnification of the part boxed in F showing the development of floral organs. Bar = 200 μm. gl, Glume; le, lemma; lo, lodicules; pl, palea; st, stamen. I, Magnification of the part boxed in G showing the development of an inflorescence meristem instead of a floret meristem. Bar = 200 μm. Sections were stained with O-Safranin-Fast Green.