Light micrographs showing morphology and histology of rsw4 and rsw7 roots. (A-C) Paired images of a roots grown under (left-hand image) the permissive treatment (8 days at 19°C) and under (right-hand image) the restrictive treatment (6 days at 19°C followed by 2 days at 30°C). (A) Wild type; (B) rsw4; (C) rsw7. Bar: 100 µm. (D-L) Cross sections of roots within the region of maximal diameter stained with PAS to show cell walls: (D-F) Wild type; (G-I) rsw4; (J-L) rsw7. The left hand column (D,G,J) shows the anatomy of plants grown under the permissive treatment, the center column (E,H,K) the restrictive treatment, and the right-hand column (F,I,L) the permissive treatment supplemented with 10 µg/ml aphidicolin for the 2 days at 30°C (wt and rsw7) or for only the second day (rsw4). Bar: 50 µm.