Fig. 10. Localisation of Sut1 mRNA in developing cotyledons of wild-type and mutant phenotype. Toluidine Blue stained sections are shown under bright-field illumination (A,C,D,F,H,J,K,M) and the same section after in situ hybridisation under dark-field illumination (B,E,G,I,L,N): signals are seen as white grains. (A) Wild-type seed of 
60 mg weight and (B,C) its cotyledons (see frame in A). (D) Mutant seed of 60 mg weight and (E,F) its cotyledons (see frame in D). (G,H) Mutant cotyledon of a 160 mg seed. Note the low signal intensity in certain regions (arrowheads). (I,J) High signal intensity of SUT1 in vacuolated cells of the outer boundary (frame in G). (K) Wild-type seed at mid-cotyledon stage. Localisation of abaxial transfer cells is indicated by an arrowhead. (L) Cotyledons (see frame in K) after in situ hybridisation (arrowhead indicates abaxial transfer cells). (M,N) Mutant seed at mid-cotyledon stage, arrowheads indicate the cotyledon to seed coat boundary. (N) Note the completely irregular pattern of the in situ hybridisation signal. ab, abaxial; ad, adaxial; ax, embryo axis; co, cotyledon; e, endosperm; ev, endospermal vacuole; sc, seed coat. Scale bars, 0.7 mm (A,D), 0.1 mm (C,F), 0.4 mm (H,L), 0.2 mm (J), 1.5 mm (K,M,N).
