The tobacco calli were cultured on MS or MS containing 0.1 mmo／L 2-aminoindan-2-phosphonic acid (AIP，inhibitor of SA synthesis，gift from Professor B．Mauch．Mani)or l mmol／L aminoxyacetic acid(A0A，inhibitor of ethylene synthesis)in dark(25±2℃)，while methyl jasmonate(MJ) were sprayed to the calli．After treatment，the contents of malondialdehyde(MDA)，active oxygen，hydrogen peroxide(H2O2)and the activities of superoxide dismutase(SOD)，lipoxygenase(L0X l and LOX3)，catalase(CAT)，ascorbate peroxidase(APX)were determined during 2-l0 days． MJ largely decreased the content ofM DA，H，O，。and the activities ofSOD，CAT， APX．By contrast，MJ increased the activity of LOX1 and the content of active oxYgen．However．MJ had little effects on the activity of L0X3． The treatment of A0A completely inhibited the effects Of MJ on M DA。active oxygen，SOD and CAT，but，AIP had 1ittle eriects on that substances and enzymes． AIP and AOA differed in the effects on the activity of APX and the MDA content，and had different efects on promoting the LOX activity induced by MJ．The results indicate there are different pathways of signal transduction in the activities of some enzymes and some metabolized substances that involved in the active oxygen burst and lipid peroxide． Ethylene plays a main role in inducing M DA，active oxygen and SOD，but SA had little efects on the induction of these substances． Thus，the effects of MJ are mainly induced by the ethylene pathway． However，SA is essential to the production of MDA and has a particular efect on modulating the activity of SOD under the condition of ethylene deficiency
