Figure 6. Naturally formed D.citri stylet sheaths within leaf midrib of Duncan grapefruit (Citrus paradisi Macfadyen).

Panel A indicates a stylet sheath segment having bulbous stylet sheath formations (bssf) within the ground tissue region of the midrib that originated from a D. citri probe on the lower surface of the midrib. Propidium iodide fluorescence staining is used to provide contrasting resolution between the tissue types and the stylet sheath structure. Panel B is a magnified view of Panel A stylet sheath (ss) region minus fluorescence, indicating the bssf areas as well as the apparent stylet canal traveling parallel to the stylet sheath core. Panel C illustrates bssf continuing within the phloem tissue and additionally illustrates the multi-branching of the sheath portion within the phloem tissue. Micrographs are DIC.