Fig. 2.

Developmental physiology of abp1 mutant seedlings. (A) Level of ABP1 transcript in abp1 mutants in comparison to the respective wild types ABP1 (abp1-5 is in Col-O, all others in Ws). Value for wt ABP1 is set as 1 (asterisk: different by P<0.05). (B) Representative light-grown seedlings (7 d; Ws, abp1 mutants). Bar=5mm. (C) Hypocotyl length of light-grown seedlings (14 d) (n=23–30; SEM, P<0.01). (D) Root development without auxin (upper row) and in the presence of 0.1 µM IAA (lower row) (n=30–39; SEM). (E) Auxin sensitivity of primary root length and (F) and lateral root number (n=30–39; SEM). Error bars are either visible or smaller than symbols. Non-overlapping symbols or error bars in E and F were significantly different from each other (P<0.01 or lower). (G) Delayed phototropic responses of hypocotyls of dark-grown (3 d) seedlings. Phototropism was induced by lateral blue light (10 µmol m^–1 s^–2) for 8h (SEM, n=70–130). (H) Delayed gravitropic responses in hypocotyls of 3-day-old dark-grown seedlings after 24h tilting by 90° (n=63–140). (I) Delayed gravitropic responses of roots of dark-grown seedlings (3 d) after 24h tilting by 90° (n=52–90). (G–I; average bending angles±SEM * P<0.05; ** P<0.01; *** P<0.001). (J) Acropetal auxin transport in roots of 4-day-old light-grown seedlings. Dark blue bars: 5–10mm from tip; purple bars: 10–15mm from tip; light blue bars: 15–20mm from tip. (n=40; *: P<0.05). (K–O) Epidermal pattern of primary leaves. (K) Wassilewskia wt; (L) abp1-8; (M) abp1-9; (N) abp1-10; (O) abp1-11. In each photo two cells are outlined for comparison. Bars=100µm. Cell areas and lobe numbers of epidermis cells are presented in Supplementary Fig. S2.