Figures 1-6: Pollen grain charging from detritus and sputter coating remediation. Figs. 1-4. Felicia smoragdina (S. Moore) Neux. (South Africa; L. C. Leach & R. D. Bayliss 12951; K). Figs. 5-6. Leavenworthia aurea Torr. (Oklahoma, Choctaw Co.; B. Amos & S. Barber 741 , BEBB). Treatment: all pollen coated with OTOTO (4) and mounted on JEOL TEMSCAN 100-CX rectangular copper specimen boats (2.4×5.6 mm with 4 mm high ends and 3 × 9 mm specimen framing marks) using carbon tape mounting adhesive. In Figs. 2, 4, and 6 pollen was pulse sputter coated for 3 minutes with gold/palladium (60/40) target in a Hummer VI Sputter Coating System. Pollen examined with a JEOL 880 scanning electron microscope equipped with a lanthanum hexaboride gun operating at 15 KeV accelerating voltage. Printing conditions (print paper grades and developing times) identical for each comparative set of micrographs. Scale bars equal 10 µµm.
Fig. 1 Two pollen grains in direct association with a highly charged detrital fragment showing darkened pollen images.
Fig. 2 Same area as Fig. 1 but after sputter coating. The pollen grains are clearly shown and the detrital fragment no longer is charged.
Fig. 3 Enlargement of pollen grain nearest to detrital fragment. Note overall "fuzzy" resolution and scan lines (lower portion of micrograph).
Fig. 4 Same pollen grain as Fig. 3, after sputter coating. Image quality is improved to resolve fine holes in the bases of the pollen spines.
Fig. 5 Pollen grain and neighboring detrital elements are highly charged.
Fig. 6 Same pollen grain as in Fig. 5, after sputter coating.