Fig. 6. AtPIN and microtubules. (A-C) AtPIN and microtubule labelling in ton mutants. (A) Microtubule arrays are disorganised. (B) AtPIN labelling in the ton2.1 mutant (weak allele). Polar pattern can still be recognised there is, however, some diffusion into lateral membranes. (C) AtPIN labelling in ton2.2 mutant (strong allele). The typical ladder-like pattern is lost, although AtPIN still labels sub-domains of the cell surface. (D-F) AtPIN and microtubule labelling after short-term treatment with oryzalin (3 hours) in isolated Zea mays root cells. AtPIN-Cy3-tubulin-FITC double labelling in (D) untreated cells, and cells treated with (E) 17 µM oryzalin, (F) 28 µM oryzalin. AtPIN polar staining is not affected by the progressive alterations of the microtubule network by oryzalin. (G-K) AtPIN labelling after long-term treatment with oryzalin (42 hours) in Arabidopsis and Zea mays roots. (G) AtPIN typical ladder-like staining pattern in untreated Arabidopsis root. (H-J) Longitudinal sections of Arabidopsis root apex treated with different concentrations of oryzalin (H) 1.7 µM, (I) 17 µM, (J) 28 µM. Initial basal polar staining pattern is lost and often replaced by labelling of the proximal side of the plasma membrane. (K) Transverse section illustrating the labelling shift to the proximal side of the cells, towards the central cylinder. (L) Longitudinal section Zea mays root treated with 17 µM of oryzalin. Relocation of AtPIN-labelling to proximal cell sides is also shown. Bars, 8 µm.