Figure 5.

Leaf Asymmetries Induced by Ectopic Auxin Application.

(A) Auxin (10 mM) applied to the ascending base of leaf primordia (bottom panels, black material is applied auxin-lanolin paste). Top panels show resulting mature leaves that develop from the primordia shown. Ectopic auxin application yields leaves with their proximal leaflets shifted distally (arrows) and increased laminar outgrowth of the terminal leaf on the side of auxin application (asterisk), features associated with the descending side of the leaf when auxin is not applied (Figure 3).

(B) Auxin application yields similar effects when applied to the descending side of leaf primordia as well, exaggerating the morphology of characteristics normally associated with this side.

(C) Application of DMSO in lanolin (control) produces leaves more symmetrical than those to which auxin is applied (n = 15).

(D) Shifts in leaflet position were measured as the difference between “a” (green), the distance to the first proximal lateral leaflet on the side of auxin application, and “b” (orange), the distance to the lateral leaflet on the unmanipulated leaf side. As shown, leaflets are significantly shifted distally on the side of auxin application (one-sample t test, P = 0.014). Note that auxin was applied to the ascending (Asc.) side of leaves twice as often as the descending (Desc.) side (n_ASC = 20 and n_DESC = 10). Such a bias makes this test conservative, as we expect the ascending side of leaves to be shifted proximally (toward the leaf base) in the absence of any manipulation (Figure 3).