Fig. 4. Pollen development is arrested in ga1-3. (A) The anther-specific markers SDS and ATA7 were used in in situ hybridization analysis to compare microsporogenesis in ga1-3 and wild type. SDS patterns appeared the same in ga1-3 and wild type whereas the ATA7 signal pattern in ga1-3 locules was significantly different to that of the wild-type control. (B) Chromosome spread experiments confirmed that pollen meiosis is successfully completed in ga1-3, resulting in tetrad formation. (C) Aniline Blue staining showed that the tetrads in ga1-3 tend to be clustered and are not found in the form of free microspores as is seen in the wild type. Scale bars: 1 µm in B; 50 µm in C.