Abstract:Arabidopsis col-0,amt1.1 and amt1.3 were used as materials. By adding 0% (T1) or 5% (T2) sucrose to the culture solution, the influences of exogenous sucrose on nitrogen and carbon metabolism of three Arabidopsis lines in nutrient solution under 20 mmol/L NH4+ were investigated. Plants grown under 4 mmol/L NH4+ were used as controls (CK). The fresh weight, the contents of chlorophyll, NH4+- N, soluble sugar and protein, the activity of glutamine synthetase (GS) and glutamate dehydrogenase (GDH), the mineral element contents of aboveground parts of Arabidopsis were determined in this study. The results showed that, the growth of three Arabidopsis lines was significantly restrained under 20 mmol/L NH4+ condition (T1) compared with 4 mmol/L NH4+ (CK). With the increasing of NH4+ concentration, the fresh weight and the GS and GDH activities were reduced, but the contents of NH4+, chlorophyll, soluble sugar, soluble proteins, N, P, K and Ca of Arabidopsis were increased, while the contents of Mg and Fe of Arabidopsis were reduced. Compared with amt1.1 and amt1.3, col-0 was more sensitive to high NH4+. Compared with T1 treatment, T2 treatment increased the fresh weight of Arabidopsis, significantly increased the contents of soluble sugar and protein, enhanced the activities of GS and GDH, reduced the contents of ammonium and chlorophyll of Arabidopsis, increased the contents of N, P, K, Ca and Mg but reduced the content of Fe in Arabidopsis. Compared with amt1.1 and amt1.3, exogenous addition of sucrose (T2) showed a better alleviation effect on high NH4+-stress in Col-0.