Defects in basipetal auxin transport are associated with altered root
flavonoid accumulation. A-D, flavonoid accumulation in the entire
root and root elongation zone of wild type (Col Wt; A and
C) and pin2 (B and D). Accumulation of
flavonoids in control and 2-h gravity-stimulated roots visualized in
situ using DPBA (yellow fluorescence) as described under
“Experimental Procedures.” The arrows indicate the
direction of the gravity vector relative to the root. Bar, 100 μm.
E, total amount of flavonoid derivatives detected in the entire root
and RT-EZ of wild type and pin2. F, gravity-induced root phenolic
compound accumulation normalized to phenolic compound accumulation in vertical
control. Values represent mean ± S.E. (n = 2-5 replicates);
*, significantly different from the wild type (Student's t
test, p < 0.05). G, representative sum of extracted ion
chromatograms [M - H]- of flavonoid derivatives found in wild type
and pin2 RT-EZ analyzed by HPLC-ESI-MS. Significantly altered
compounds are indicated by arrows. Peak numbers correspond to
flavonoid derivates listed in Table
1. Note the 10 times lower intensity scale for pin2 root
elongation zone in comparison to wild type.