Fig. 11. Calcium ratio imaging of non-growing, BFA-treated (A) and growing (B) L. longiflorum pollen tubes. (A) Plots show the typical movement of material into the subapical membrane aggregation (closed circles; c.f. Fig. 2) and the apical intracellular calcium concentration (open squares: ratio OG 488/TR). Images are (top to bottom): a Texas Red fluorescence image (the BIA and associated aggregates appears dark); the corresponding projected TR image time-series displayed as a single `negative' image to show the path of movement of material; the corresponding ratio image. The areas sampled to produce the plots (rectangles) and location of the BIA (circled) and associated aggregates (arrowhead) are indicated. (B) Untreated pollen tube: plots show the typical oscillatory fluctuation in apical intracellular calcium concentration during growth (open squares: ratio OG 488/TR; the area sampled is shown on the insert image) and corresponding fluctuation in growth rate (closed circles). Insert images show OG 488/TR ratios corresponding to a consecutive minima and maxima in the tip-focused cytosolic calcium gradient. Bars, 10 µm.