Fig. 3

Plastids density and expression of starch synthesis genes during embryo formation in ‘Jersey’ and ‘Mercada’ cultures. a Types and density of plastids present in microspores and microspore-derived embryos at successive stages of culture. Initial proplastid was characterised by a low electron density and the presence of single invaginations from the inner membrane, the differentiating proplastid by much higher electron density and single invaginations from the inner membrane, amyloplast was filled with starch grains. Values present mean of n ≥ 3 with SD. b, c The relative expression level of genes related to reserve starch (b) and assimilatory starch (c) synthesis in ‘Jersey’ and ‘Mercada’ cultures. Graphs show mean values of n ≥ 3 with SEM. Relative expression level was normalised to ML microspores of cv. ‘Jersey’. An asterisk presents a value significantly different between cultivars at a certain day of culture. A hash indicates a value significantly different from the preceding day of culture within cultivar (Tukey’s test, P < 0.05). ML – mid-to-late microspore, PM – pre-treated microspores, dC – day of culture