Methyl jasmonate, ammonium, and leaf senescence in rice

The possible involvement of ammonium in the regulation of methyl jasmonate (MJ)-promoted senescence of detached rice (Oryza sativa) leaves was investigated. MJ was effective in promoting the senescence of detached rice leaves. The effect of MJ on the senescence is associated with the accumulation of ammonium. MJ-promoted senescence and ammonium accumulation is not specific for the rice cultivar used in this study. MJ also promoted senescence and stimulated the accumulation of ammonium of five other rice cultivars. The accumulation of ammonium in detached rice leaves by MT is attributed to a decrease in glutamine synthetase activity and an increase in reduction of nitrate.