Top panel: Pseudocolored image of a pollen tube of Lillium longiflorum injected with fura dextran (Cat. No. F3029). The cell continues elongating and clearly shows a Ca2+ gradient.
Bottom panel: The same pollen tube after injection with dibromo BAPTA (Cat. No. D1211) remains healthy but is no longer elongating. The images were contributed by Debra Miller, Dale Callaham, David Gross and Peter Hepler, University of Massachusetts.