Validation and flow chart of the wheat germ agglutinin-staining protocol. A) Time course of gamete egress at 5, 10 and 15 min after the addition of 20 μM XA. Error bar is SD from four biological replicates. B) Effect of cell fixation in the measurement of gamete egress. Data from three independent experiments, error bar is SD. C) Flow chart of the WGA-staining protocol. WGA: wheat germ agglutinin, AM: activation medium, RT: room temperature, PFA: paraformaldehyde, BF: bright field.