Fig. 4.

Disrupted endosperm and embryo development in GhKOR1-down-regulated transgenic cotton. The resin-embedded longitudinal sections cut from 10 DPA seeds were stained with Toluidine Blue. The endosperms are enclosed by yellow dotted lines. (A) WT seed section. Note that the endosperm was cellularized and well organized with cell walls evidently visible between the cells (arrows), and the embryo has developed to the heart stage. (B) RNAi line1 seed section. Note the much reduced endosperm cell size and cellularization. The latter is indicated by the irregular cell walls as compared with the WT. Also different from that in the WT (A), the embryo is still at the globular stage. (C) RNAi line5 seed section exhibiting similar endosperm and embryo phenotype to those of RNAi line1 in (B). The overall area of the endosperm appeared similar to that in the WT (A). However, the cells are irregular in shape (arrows) and the embryo is at the globular stage. (D) Co-S line1 10 DPA seed section. Note the similar phenotype to that of the RNAi line1 in (B) characterized by smaller and less cellularized endosperm cells and the fact that the embryo is at the globular stage. en, endosperm; em, embryo; n, nucellus; isc, inner seed coat; tc, transfer cell indicated by arrowheads. Three biological replicates were observed for each line, with similar results. Representative images are provided. Scale bars=50 μm in A–D.