ARR22 is expressed in the chalaza of developing seeds. (A) Steady-state ARR22 transcript levels in different organs and at different developmental stages of Arabidopsis as determined by quantitative RT-PCR. Data are expressed as mean +/- SD (n = 3) (B) Scheme of Arabidopsis seed anatomy adapted according to Debeaujon and colleagues . Note the location of the chalaza. (C) Confocal images of transgenic seeds at different developmental stages expressing a P
::GFP construct. Bright field, GFP images and overlays are presented from the left to the right. The bars represent 100 μm. (D) Immunolocalization of GFP on cryosections prepared from developing seeds of P
::GFP transgenic plants using a GFP-specific antibody (anti-GFP). The nuclei of the cells were visualised by DAPI staining (DAPI). The dotted line confines the chalaza area. The bars represent 20 μm.