Fig. 3. The DAF-2DA-positive organelles are peroxisomes. (A-D) Confocal images of growing lily pollen tubes incubated in DAF-2DA (green) and in organelle-specific dyes (red). No co-localization was found in the endomembrane system (A, BodipyTR), mitochondria (B, Rhodamine 123) or acidic organelles (C, LysotrackerRed). (D) Peroxisomes were then tagged by transient transformation of pollen grains with a construct containing the pollen-specific LAT52 promoter driving an ECFP-peroxisome targeting signal (PxTS) fusion. Pollen tubes were observed 10 hours after germination. The NO-producing organelles (DAF-2, green) show an almost complete co-localization with the ECP signal (PxTS-CFP, blue), as shown in the merged image. Scale bars: 15 µm.