Fig. 4. The ale2 mutation affects fertility in a semidominant manner in the acr4 mutant background. (A) Inflorescence of self progeny obtained from an ale2-1/+; acr4-5/+ parent on the Ler background. Plants that were double homozygous for the ale2 and acr4 mutations were viable and resembled ale2 single-mutant plants. (B) Number of enlarged seeds per silique in the progeny of ale2-2/+; acr4-5/+ plants on the Ws background. Seeds from at least ten siliques were scored for each genotype. The genotype at each locus is indicated. Notice that, whereas ale2/+ plants were fully fertile (lanes 2 and 5) in the presence of the wild-type ACR4 allele, ale2 mutation affected fertility in a semi-dominant manner in the acr4 mutant background (indicated by the asterisk above lane 8; compare to lane 7). Essentially the same results were obtained for progeny of ale2-1/+; acr4-5/+ parents on the Ler background (data not shown). (C) Morphology of ovules. ale2 acr4 double mutants produced fused ovules that were similar to those of the ale2 single mutant. W, wild type; H, heterozygous; m, homozygous. Scale bars: 1 cm in A; 20 µm in C.