No abstract

Umbelliferone decreases the elongation rate and initiates a swelling response in cucumber roots. Associated with these growth effects are increases in peroxidase activity in water soluble, salt soluble, and wall bound fractions. The effect on elongation is reversible and is separated in time from the swelling response. Increased peroxidase levels appear after the elongation rate has been reduced but coincident with the swelling response. It is suggested that umbelliferone effects axial elongation and radial expansion through different mechanisms.