Fig. 9. Effects of Ca²⁺ and PLC inhibitors on organellar Ca²⁺ imaged with chlortetracycline. In normal growing hyphae significant fluorescence is detected associated with vesicles at the tip. (A) During Ca²⁺ imaging typical response (reduction of fluorescence at the tip, and an increase behind) is observed after the addition of 25 µM 2-APB at time 0 (n=18). At the same time hyphal elongation stops. (B) Similar results are obtained after treatment with 10 µM U-73122 (n=15). (C) Following the treatment with 400 µM neomycin similar effects occur (n=9). (D) In hyphae treated with cyclopiazonic acid the tip high Ca²⁺ is dissipated, but no increase in fluorescence behind the tip is observed (n=15). Bars, 10 µm.