Table VII.

Effects of excision and localized IAA application on lateral root development

Treatment[IAA]Lateral Root No.Root LengthLateral Root Density6-a
μm mm
Intact plants6-b 0.028.6  ± 2.351.9  ± 3.10.56  ± 0.04
Shoot excised6-b 0.06.4  ± 0.445.7  ± 1.90.14  ± 0.01
Root tip excised6-b 0.020.8  ± 0.827.7  ± 0.80.76  ± 0.03
Shoot excised6-c 0.06.0  ± 1.042.4  ± 2.10.14  ± 0.02
Shoot excised0.16.3  ± 0.946.7  ± 2.00.13  ± 0.02
Shoot excised1.09.3  ± 1.243.5  ± 1.60.21  ± 0.03
Shoot excised10.013.1  ± 1.336.7  ± 1.50.36  ± 0.03

Plants were treated by shoot or root-tip excision and 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.

    • F6-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.

    • F6-b Five-day-old seedlings were treated and grown for 3 additional d in the light.

    • F6-c Eight-day-old seedlings were treated and grown for 3 additional d in the dark.