Figure 6. Ratcheting prevents mechanical competition between neighbouring cells.

(a) Schematics of mechanical competition between contraction pulse in a central cell (orange, black arrowheads) and contraction pulses in its neighbours (yellow, green arrowheads) leading to a lower magnitude of apical constriction in the central cell. (b) twi-RNAi pulses, but not wild-type pulses, interact competitively. For pulses of similar magnitudes, the maximum constriction rate attained during a pulse (y axis) and number of neighbouring pulses (x axis) were quantified. For pulses within the 91–100th percentile amplitude-bin, having more neighbouring pulses correlates with less apical constriction in twi-RNAi cells. In wild-type cells, neighbouring pulses are not associated with lower constriction rates in the central pulse. The red lines and shaded regions denote the means and s.d.'s, respectively. (c) Ratcheted wild-type pulses are associated with cooperative apical constriction. For pulses with similar amplitudes, polyserial correlation scores were quantified between the maximum constriction rate attained during a pulse and the number of neighbouring pulses24. Error bars show estimated s.d.'s24.