Table I.
Effect of auxin inhibitors on Arabidopsis seedling development
| Inhibitor/Treatment | Cotyledon Morphology | Leaf Morphology | Leaf Fusion | Inflorescence Morphology | Root Gravitropism |
|---|---|---|---|---|---|
| μm | |||||
| HFCA | |||||
| 0 | Normal | Normal | Not obs. | Normal | 88 (50) |
| 1 | Normal | Normal | 3% (157) | Normal | 92 (50) |
| 5 | Normal | Normal | 9% (189) | Abnormal | 14 (50) |
| 10 | Normal; ep. | Normal | 16% (125) | Abnormal | 8 (50) |
| 30 | sl. st.; ep. | sl. st. | 18% (147) | Abnormal | 0 (20)# |
| 50 | v. st.; ep. | v. st. | 16% (169) | Abnormal | ** |
| 100 | v. st.; chl.; ep. | v. st.; chl. | 14% (192) | Abnormal | ** |
| TIBA | |||||
| 0 | Normal | Normal | Not obs. | Normal | 85 (69) |
| 1 | Normal | Normal | 6% (144) | Normal | 38 (86) |
| 5 | sl. st. | sl. st. | 12% (156) | Abnormal | 16 (96) |
| 10 | sl. st; ep. | sl. st.; ep. | 11% (181) | Abnormal | 5.8 (104) |
| 30 | sl. st.; ep. | sl. st.; chl.; ep. | 22% (196) | Abnormal | 0 (113) |
| 50 | v. st.; chl.; ep. | v. st; chl.; ep. | 15% (112) | Abnormal | ** |
| 100 | v. st.; | – | – | – | ** |
| NPA | |||||
| 0 | Normal | Normal | Not obs. | Normal | 90 (49) |
| 1 | Normal | sl. st. | 21% (194) | Normal | 39 (44) |
| 5 | Normal; ep. | sl. st. | 18% (170) | Abnormal | 14 (63) |
| 10 | Normal; ep. | st. | 16% (222) | Abnormal | 4 (66) |
| 30 | st.; ep. | st. | 15% (155) | Abnormal | 3 (64) |
| 50 | v. st.; ep. | v. st. | 7% (182) | Abnormal | ** |
| 100 | v. st.; ep. | v. st. | 1% (160) | Abnormal | ** |
| PCIB | |||||
| 0 | Normal | Normal | Not obs. | Normal | 85 (120) |
| 1 | Normal | Normal | Not obs. | Normal | 60 (148) |
| 5 | Normal | Normal | Not obs. | Normal | 77 (106) |
| 10 | Normal | Normal | Not obs. | Normal | 64 (115) |
| 30 | sl. st.; | sl. st. | Not obs. | Normal | 18 (89) |
| 50 | v. st.; ep. | st.a; ep. | Not obs. | Normal | 16 (100) |
| 100 | v. st., chl., ep. | v. st.a; chl.; ep. | Not obs. | Normal | ** |
Cotyledon and leaf morphology: sl. st., slightly stunted; v. st., very; stunted; st., stunted; chl., chlorotic; ep., epinastic. Leaf fusion: percent indicates proportion seedlings showing any fusion of first leaf pair, numbers in parenthesis indicate the number of seedlings scored. Abnormal inflorescence morphologies included inflorescences containing flowers with reduced numbers of stamens and increased numbers of petals and inflorescences devoid of flowers and that resembled pin-like structures. Root gravitropism was scored by assessing whether roots penetrated the agar; numbers in parenthesis indicate number scored.; **, roots too short to score; #, scoring based on a small fraction of plants with roots more than 1 cm.
Some plants grown in 50 and 100 μM PCIB produced narrow and elongate leaves, data not shown.