Fig. 1. Expression of P-INO reporter genes in wild type and ino-1 plants. Stages: (A,F,K,P,U,Z) 2-III; (B,G,L,Q,V,AA) 2-IV; (C,H,M,R,W,BB) 2-V; (D,I,N,S,X,CC) 3-I; (E,J,O,T,Y,DD) 4-I. (A-E) Scanning electron micrographs of wild-type ovules. In A a late developing ovule at stage 1 is indicated with an asterisk. (F-J) Composite figures of DIC and confocal INO:GFP fluorescence images and (K-O) respective INO:GFP fluorescence alone in complemented ino-1 ovules. P-INO::INO:GFP::NOS3' fluorescence is detectable only on the abaxial side of the ovule primordium and the abaxial layer of the outer integument. (M,N) Apparent internal localization of INO:GFP is from glancing sections through adjacent surface layers. (P-T) DIC images of wild-type ovules of P-INO::GUS::INO3' transgenic plants stained for GUS activity using 12.5 µg/ml X-gluc. (U-Y) Scanning electron micrographs of ino-1 ovules. (Z-DD) ino-1 ovules stained for P-INO::GUS::INO3' activity using 125 µg/ml X-gluc and visualized using DIC light microscopy. In all panels, the abaxial side (toward the base of the gynoecium) of the ovule is to the left, and adaxial is towards the right. n, nucellus; i, inner integument; f, funiculus; o, outer integument; m, micropyle; arrowhead, outer integument primordium. Scale bar: 25 µm in A-C,F-H,K-M,P-R,U-W,Z-BB; 30 µm in D,I,N,S,X,CC; 50 µm in E,J,O,T,Y,DD.