Abstract
Root of higher plants takes different growth patterns in response to environmental stimuli; for example, Arabidopsis root on the surface of agar plates at an angle of 45o to the vertical exhibits a wavy growth pattern that is caused by periodic reversion of rotation of the root tip. This is thought to be an obstacle-escaping response. Previously we found that some terpenoids, plant volatiles, induce accumulation of defense genes in plant tissues. Here we report that a monoterpene induce Arabidopsis roots being placed in a vertical position to take wavy growth pattern similar to obstacle-touching stimulus. It induces more wavy growth pattern on root being placed at 45o than 90 o. It has little effect on the gravity sensitivity, auxin accumulation and cell division at the root tips. Other monoterpenes, of which chemical structures are similar to the volatile, induce expanded root tip but not wavy pattern.
