Figure 6.

RMD-mediated F-actin organization regulates tobacco pollen tube growth. Data are from transiently transformed tobacco pollen tubes. All transgenes are expressed by the pollen-specific Lat52 promoter. A, RMD-mediated F-actin organization contributes to tobacco pollen tube growth. Lifeact is an actin-binding protein to trace F-actin arrays (red signals). Images of pollen tubes were taken 3 h after germination. BF, Bright field. Bars = 10 μm. B, Growth response to RMD. Pollen tube length was measured 3 and 5 h as indicated after transformation with various versions of RMD fused with eGFP or single eGFP (n > 40 of each set). Control indicates wild-type tobacco pollen tubes. C, Statistics of pollen tube width as mentioned in B. Data were collected 3 h after transformation with various constructs in four independent experiments (n > 40 of each set). D, Contribution of RMD-eGFP and control (single eGFP) to pollen tube growth. White lines show the distance grown by the tubes in a comparable period (0–300 s). Yellow bar = 5 μm. E, Growth rate comparison. Growth rates were averaged from control (eGFP; n = 16) and RMD-eGFP (n = 19) tubes individually monitored for durations between 30 min and 1 h in three independent comparative experiments. All error bars represent sd of three biological repeats. Student’s t test: **, P < 0.01.