Inhibition of methyl jasmonate-promoted senescence in rice leaves by a metal chelator, 2,2 '-bipyridine

The possible mediatory role of transition metals in methyl jasmonate- (MJ-) induced senescence of rice leaves was investigated. Metal chelators (2,2'- bipyridine, 8-hydroxylquinoline and 1,10-phenanthroline) reduced MJ-promote d senescence of rice leaves. The reduction of MJ-promoted senescence by 2,2 '-bipyridine(BP) is closely associated with the decrease in lipid peroxidat ion and increase in activity of superoxide dismutase (SOD). Our results sug gest that iron or copper plays a major role in MJ-promoted senescence of de tached rice leaves. BP-reduced senescence of detached rice leaves induced b y MJ was reversed by adding Fe2+ or Cu2+, but not by Mn2+ or Mg2+. Reductio n of MJ-promoted senescence of detached rice leaves by BP is most likely me diated through chelation of iron or copper and an increase in SOD activity.