arr22/gARR22 plants show increased ARR22 transcript levels in the siliques but no alterations in female gametophyte development. (A) Inflorescence images of arr22-2 and arr22-3 plants complemented with the wild type ARR22 genomic fragment (gARR22) or the empty vector (vector) (T1 generation). Details of the apical inflorescence are shown in the second row. The bars represent 10 mm. (B) ARR22 transcript levels in wild type and arr22-2 plants complemented with a wild type genomic ARR22 fragment (gARR22). Total RNA was isolated from the emerging siliques of the inflorescences in three replicas (A-C) and subjected to semiquantitative RT-PCR. PCR was performed with ACTIN2 or ARR22 specific primers at indicated numbers of cycles. (C) Differential interference contrast microscopy images of developing ovules and seeds of a sterile arr22-2/gARR22 plant and wild type. Ovules and seeds were excised from the siliques harvested from the same nod relative to the apex of the inflorescence. I, developed female gametophyte; II, fertilized seed with the zygote and four endosperm nuclei; III, early embryonic stage. The positions of the synergid nucleus (sn), egg cell nucleus (en), central cell nucleus (cn), zygotic nucleus (zn), endosperm nucleus (edn) and embryo (emb) are indicated by black arrows. The bars represent 50 μm. Figure legend text.