Table V.

Reversal of NPA-induced lateral root inhibition by localized IAA application

Agar4-aLateral Root No.Lateral Root Density
UpperLower
ControlControl6.7  ± 0.850.19  ± 0.02
IAAControl10.0  ± 0.560.43  ± 0.03
ControlNPA0.33  ± 0.140.02  ± 0.01
NPAIAA4.25  ± 0.730.24  ± 0.04
IAANPA1.72  ± 0.460.08  ± 0.02

After the indicated treatments, lateral root number and root length were determined after 4 d of additional growth in the light. The reported values are averages ± se of 10 plants.

• F4-a Two, thin (1-mm), parallel lines of agar either with or without 10 μm IAA and 100 μm NPA were applied to the root-shoot junction of seedlings that were 4 d old. This technique allowed for the simultaneous application of two compounds to seedlings. Although both lines were over the root-shoot junction of the seedlings, one line was closer to the plant shoot (the Upper line) and the other was closer to the root (the Lower line).