The vln2 Root Has a Hypergravitropism Response.

(A) and (B) Hypersensitive gravity response of vln2 roots compared with those of the wild type during a 10-h time course after their reorientation.

(C) Suppression of hypergravitropism in vln2 roots by IAA (10 nM) treatment.

(D) and (E)  vln2 roots were less sensitive to the PAT inhibitors NPA ([D]; 10 nM) and TIBA ([E]; 10 nM) with regard to gravitropic growth.

(F) and (G) Asymmetric staining (F) and quantitative analysis (G) of GUS activity in the vertically grown root of vln2 and the wild type transformed with the DR5:GUS reporter. OS and IS, outer and inner side of the curved vln2 root, respectively.

(H) and (I) Faster establishment of asymmetric auxin distribution in vln2  (H) and quantitative analysis of GUS activity (I) following 20 min gravistimulation.

Arrows indicate gravity (g) direction, and arrowheads indicate the side of higher auxin accumulation in (F) and (H). Error bars indicate sd of the means of 21 seedlings in (B), 16 seedlings in (C) and (D), and 174 seedlings in (G) and (I). Asterisks indicate significant difference at *P < 0.05 and **P < 0.01, respectively, based on Student's t test.