Fig. 5. Cell identities in bicellular msi1 pollen. (A-F) Wild-type Arabidopsis pollen at the tricellular stage. (G-L) Bicellular and tricellular pollen segregating from msi1/+ plants. (A,G) Fluorescence images of pollen grains stained with DAPI. (B,H) The same pollen grains as in A,G, respectively, expressing the vegetative cell marker AC26-Histone2B-mRFP1. (C,I) Pollen grains expressing the generative lineage marker pDUO1-DUO1-mRFP1. (D,J) Pollen grains expressing the generative lineage marker E1-GFP. (E,K) Pollen grains expressing the sperm cell marker HTR10-mRFP1. (F,L) Pollen grains expressing the sperm cell marker ATGEX1-GFP. GFP was examined using the 488 nm excitation line of an argon laser and an emission filter long pass of 510 nm. Fluorescence of mRFP1 was examined using the 543 nm excitation line of a HeNe laser and an emission filter of 585-615 nm. Scale bars: 10 µm.