Fig. 5. Hormonal responses of wild type and ral1. (A,C,E-H,M-P,Q,S,U) Wild type. (B,D,I-L,R,T,V) ral1. (A-D) Seedlings 1 week (A,B) or 3 weeks (C,D) after callus induction on 2 mg/l 2,4-D. (E,F,I,J,M,N) Calli at the stage of transfer to the induction medium (E,I,M) and 3 weeks after (F,J,N) the transfer. Medium contained either 2 mg/l 2,4-D (E,F,I,J) or 1 mg/l 2,4-D (M,N). (G,H,K,L,O,P) Sections through the calli in F (G,H), in J (K,L), or in N (O,P). (Q-V) DR5-GUS expression in the root of 1-week-old seedlings grown for 24 hours on filter paper moistened with water (Q,R), with 0.1 (S,T) or 1 (U,V) µM NAA. (W,X) Frequency of shoot (W) or root (X) regeneration via somatic organogenesis in callus tissues grown on hormone-free medium (black diamond, wild type; black triangle, ral1) or on medium supplemented with cytokinin (black square, wild type; cross, ral1). The results represent the mean±s.e.m. of two separate experiments each performed on a population of 80-100 calli per genotype and per treatment. Difference between wild-type and ral1 populations as determined by repeated-measures analysis of variance (single-factor ANOVA) was significant (P<0.001) at all time points. (Y) Relative elongation over 24 hours of wild-type seminal (white boxes) and adventitious (grey boxes) roots and ral1 (black boxes) roots in the presence of 0.05 µM 2,4-D or 0.1 µM NAA. The results represent the mean±s.e.m. of two separate experiments each performed on a population of 20-35 seedlings per genotype and per treatment. Asterisks indicate the significance of difference between wild-type and ral1 populations as determined by repeated-measures analysis of variance (single-factor ANOVA). ^*0.01P<0.05, ^**0.001P<0.01. b, shoot base; pe, proembryonic structure; s, scutellum. Scale bars: (A-D,E,F,I,J,M,N) 2 mm (G,K) 100 µm (H,L,O,P) 25 µm (Q-V) 50 µm.