Abstract
Plants that are grown in windy conditions or exposed to repetitive touch stimulation are shorter, stockier, and often have altered flexibility. This is known as thigmomorphogenesis, a process in which ethylene is strongly implicated. In the present study, we therefore examined whether ethylene participated in touch response of roots to hardness.
We previously reported a simple bioassay based on touch response of roots to physical hardness of two-tiered solid growth mediums in Arabidopsis thaliana. Using this bioassay, wild type roots grown with ethylene biosynthesis inhibitors (AVG and AOA) and those of two ethylene-insensitive mutants (etr1-1 and ein2-1 ) displayed increased bending in response to hardness at the boundary between the two layers compared to control roots. In contrast, wild type roots treated with ACC displayed reduced bending compared to control roots. Further studies are now in progress to examine expression profiles of ACC synthase in thigmotropic responses.
