1. Purple: H + -ATPase; blue: AUX1; dashed arrow: diffusion Yellow: PIN proteins; red: PGPs

2. PINs/PGP proteins: Tissue-specific distribution of PIN efflux facilitator proteins

3. br2 mutant: Normal tassels and ear, but compact lower stalks

4. Auxin transport inhibitors efflux inhibitor influx inhibitor Aglycone flavonoids displace NPA isoflavones

5. Actin-dependent PIN complex cycling Auxin transport inhibitors may act by interfering with PIN1 complex cycling Web Essay 19.1 PLoS ONE (January 2008) In dark: PIN2 , in vacuole; In light: predominantly in PM

6. Physiological effects of auxin – cell elongation Endogenous vs. Exogenous auxin Oat coleoptile sections Suc maintain turgor pressure; can be substituted by KCl; 15 min lag time

7. The optimal auxin concentration – pea stem or oat coleoptile sections ppm (ethylene induction) For roots: opt. 10 -10 to 10 -9 M; 10 -6 M inhibition Not only for IAA level but also for auxin types for different cells

8. 10  M IAA, 2% sucrose The characteristics of auxin induce stem growth: acquire energy is inhibited when the presence of inhibitor of metabolic, protein synthesis (cycloheximide), or RNA synthesis the limiting time of lag phase could not be shortened  some biochemical machinery involved 0.5 h

9. Auxin-induced elongation vs. cell wall acidification Maize coleoptile lag time

10. Current models for IAA-induced H + extrusion (cell wall loosening proteins) ABP1: track H + -ATPase to membrane (auxin-binding protein) Receptor (?) p. 503 polyubiquitin