Destiny of endo-PM during maize fertilization. Tracking of NLD:mCitrine marking the endo-PM during pollen tube growth to the maize ovule by confocal imaging (Z-projections). Calcofluor-white (CFW), mCitrine, and auto-fluorescence (AF) channels are used to visualize the cell walls, NLD:mCitrine, and autofluorescence, respectively. (A) Control pollination of a WT ovule with WT pollen. It allows evaluation of autofluorescence of the degenerating synergid (DS) without NLD:mCitrine signal. Video 6 shows the Z-stack. (B and C) NLD:mCitrine location within the embryo sac, after pollen tube rupture (which could be monitored thanks to the autofluorescence of the degenerating synergid cell). After pollen tube rupture, the NLD:mCitrine protein locates at the apical region of the egg cell apparatus. Arrows show the NLD:mCitrine signal specifically detected in the mCitrine channel. Arrowhead in B represents NLD:mCitrine signal from another arriving pollen tube. Videos 7 and 8 show Z-stack and 3D projection, respectively. (D) WT embryo sac observed 44 h after pollination with NLD:mCitrine pollen; no mCitrine signal was detected. Video 9 shows 3D projection. ES, embryo sac; NU, nucellus; OV, ovary tissue. Scale bars = 50 µm.