Fig. 5. Relationship between the mean velocity and global amplitude of the artificially induced Ca²⁺ waves and the intensity of the stimulus. Points have been obtained as in Fig. 4 with the same parameter values, except for the rate of gPtdIns(4,5)P₂ influx. For influx rates lower than 0.03 µM second^-1, the Ca²⁺ waves do not propagate throughout the whole egg (abortive waves). Conversely, for influx rates higher than 0.05 µM second^-1, the Ca²⁺ increases occur nearly homogeneously over the whole egg.