Figure 9. Transmission electron micrograph of cytologically normal PI ectonema 

 boryanum . Note regular cell septae (arrow) and polyhedral bodies (PB). 

 (X28,000). 



Figure 10. Transmission electron micrograph of PI ectonema boryanum treated 

 with 0.1 yg-at/£ Pb. Note increased vacuolization of the cell, ap- 

 parent reduction in number of polyhedral bodies, and the presence of 

 numerous polyphosphate bodies (PP). (X28,000). 



Figure 11. Transmission electron micrograph of PI ectonema boryanum treated 

 with 0.1 yg-at/£ Zn. Note increased vacuolization of the cell, ap- 

 parent reduction in the number of polyhedral bodies, numerous poly- 

 phosphate bodies (PP), and lack of cell division. (X45,000). 



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