The toxic effects of diethyl phthalate on the activity of glutamine synthetase in greater duckweed (Spirodela polyrhiza L.)

► GS activity and protein accumulation under DEP-induced stress were investigated. ► GS activity was reduced with the increase in DEP stress. ► Oxidative stress generated by DEP led to the GS2 and D1 degradation in duckweed. ► DEP triggers the synthesis of ROSs to inhibit ammonia assimilation. ► DEP also disrupts protein accumulation in the chloroplast.