Table VIII.

Effects of localized IAA application on lateral root development in dark-grown plants

[IAA]Lateral Root No.Root LengthLateral Root Density7-a
μm mm
0.00.1  ± 0.133.5  ± 2.50.00  ± 0.00
0.10.7  ± 0.431.7  ± 1.40.02  ± 0.01
1.02.1  ± 0.427.6  ± 4.10.09  ± 0.027-b
5.06.0  ± 0.515.4  ± 0.80.40  ± 0.027-b
10.09.3  ± 0.713.0  ± 0.60.70  ± 0.077-b

Seven-day-old seedlings were treated by application of agar containing IAA at the indicated concentrations to the root-shoot junction. After 3 additional d of growth, lateral roots were counted and the length of the primary roots was measured. The reported values are averages ± se of 10 plants.

    • F7-a The lateral root density was calculated by dividing the number of lateral roots by the primary root length for each plant, and is reported as the number of lateral roots per millimeter of primary root.

    • F7-b The increase in lateral root density was statistically significant, as judged by Student'st test (P ≤ 0.0008).