Possible Involvement of Active Oxygen in Clomeprop Hydrolytic Metabolite-Induced Electrolyte Leakage from Radish Roots

Abstract

Involvement of active oxygen in clomeprop [2-(2,4-dichloro-m-tolyloxy) propionanilide] hydrolytic metabolite DMPA [2-(2,4-dichloro-m-tolyloxy) propionic acid]-induced electrolyte leakage from radish roots was investigated. Treatment of DMPA to radish roots caused an increase of electrolyte leakage from the roots and suppression of lateral root growth. Some scavengers of active oxygen species reduced the DMPA-induced ion leakage; in particular, singlet oxygen scavengers, 1, 4-diazabicyclo-[2,2,2]octane (dabco) and L-histidine, significantly supressed the leakage and restored the growth of lateral roots. Root-applied free radical scavengers or singlet oxygen scavengers also suppressed the DMPA-enhanced peroxidation of lipids in radish roots to some extent. However, pre-treatment of free radical scavengers or singlet oxygen scavengers to roots had no effect on DMPA-induced ethylene production. These results suggest that active oxygen is directly involved in the DMPA-induced electrolyte leakage from radish roots and growth inhibition of lateral roots.