Abstract:A solution culture experiment was conducted to study the effects of SNP on plant growth, photosynthesis, antioxidant enzyme activity and nitrogen metabolism in cucumber seedlings under NaHCO3 stress. The results indicated that 100 μmol/L SNP promoted the growth of cucumber seedlings and increased chlorophyll and carotenoid contents, net Photosynthetic rate (Pn), Fv/Fm and ΦPSⅡunder NaHCO3 stress. Compared with control, the activities of nitrate reductase (NR), glutanine synthetase (GS) and glutamate synthase (GOGAT) were significantly inhibited by NaHCO3 stress and SNP increased their activities.