Timing of the Auxin Response in Etiolated Pea Stem Sections

Abstract

The short term growth response of etiolated pea stem segments (Pisum sativum L., var. Alaska) was investigated with the use of a high resolution growth-recording device. The immediate effect of treatment with indole-3-acetic acid is an inhibition of growth. This inhibition lasts about 10 minutes, and then the rate of elongation rises abruptly to a new steady rate about 4 times the rate of elongation before auxin treatment. This rapid steady rate of elonga-tion, however, continues for only about 25 minutes before declining suddenly to a lower steady rate of growth about 2 times the rate of elongation before the addition of auxin.