Fig. 2. ga1-3 plants fail to produce tricellular pollen grains. (A) Pollen grains from various genotypes examined by SEM. Pollen grains from ga1-3 plants lacking RGL1, RGL2 and RGA (Q2), or RGL2 and RGA (not shown) were almost identical to wild-type pollen grains, being oval shaped with long indented lines on the surface. In ga1-3 plants, the cells contained in a locule appeared to remain as microspores, being round and, in some cases, with short indented lines on the wall surface. Pollen grains from ga1-3 plants lacking RGL1, RGL2, GAI and RGA (penta) were similar to wild-type pollen grains but were slightly more wrinkled in appearance. (B) DAPI staining showed that pollen grains from ga1-3 plants lacking RGL1, RGL2 and RGA (Q2), or RGL1, RGL2, GAI and RGA (penta) are tricellular (as in the wild-type control). By contrast, the majority of the cells in the anther locule of ga1-3 had either no detectable nucleus or only a single condensed nucleus whereas only 6% had two or more than two nuclei. (C) Frequencies of tricellular pollen grains in anther locules of various genotypes as revealed by DAPI staining as shown in B.