Figure 5.

Pollen defects in the tex2 alleles. A, The At5g65000 gene region. One of the two transcripts supported by the existence of ESTs is shown. Exons are shown as rectangles, with black boxes representing coding regions. Positions of mutations in tex2-1 to tex2-4 alleles are shown. The second predicted transcript differs from this one after exon 5 and, therefore, should also be affected in all the mutant alleles. nt, Nucleotides. B, Transmission electron micrographs of pollen grain sections from the wild type (WT), tex2-1, tex2-2, and tex2-3. Exine is abnormally thin in the tex2 mutants. Bars = 1 μm. C, tex2 pollen grains are sensitive to acetolysis. Top panels, pollen grains of the wild type, tex2-2, and tex2-3 mock treated with 50 mm Tris-HCl, pH 7.5, have similar morphology. Bottom panels, wild-type pollen grains treated with the acetolysis mixture remain intact, whereas tex2-2 and tex2-3 pollen grains are lysed after acetolysis. Bars = 20 μm. D, tex2-4 plants are sterile and have short siliques compared with the wild type. [See online article for color version of this figure.]