Expression analysis of barley Type I-like HvMADS-box genes. A) Qualitative RT-PCR expression analysis of HvOS1 and HvOS2 barley Type I-like HvMADS-box genes. R, roots; AM, apical meristem; YS, young shoots; L, Leaves; IF, immature flower; HvActin, was used as the internal control. B) Quantitative real-time RT-PCR analysis of Type I-like HvMADS-box genes in different seed developmental stages and in two barley cultivars. Expression values were normalized to those of HvActin. The relative expression ratio of each sample is compared to the control group which was C5 (Caresse immature flowers). C, cultivar Caresse, (white bars); IP, cultivar Ippolytos (grey bars). 5, Immature flowers; 6, Seed 1–3 DAF; 7, Seed 3–5 DAF; 8, Seed 5–10 DAF; 9, Seed 10–15 DAF; 10, Seed 15–20 DAF. Data represent mean values from two independent experiments with standard deviations. Values significantly different (P < 0.05) from the control group (C5) are marked with an asterisk. C) Spatial expression of HvOS2 in barley seeds. In situ localization of HvOS2 in barley seeds by mRNA in situ hybridization analysis. Left, transverse section of developing seeds at 10 DAF hybridized with the antisense probe. Right, transverse section of developing seeds at 10 DAF hybridized with the sense probe, as negative control. a, aleurone; e, endosperm; p, pericarp.