FIGURE 3 Effects of exogenous melatonin on the activities of enzymes in the AsA-GSH cycle and nitrogen metabolism and enzyme gene expression in seedlings under NaCl stress. Data are presented for (a): AsA, GSH, AAO, and DHAR, (b): GR, GPX, nitrate nitrogen content, ammonium nitrogen content, (c): NR and GS, GOGAT and OsGR3 , (d):OsGPX1 , OsNR2 , OsGS1 , and OsGOGAT1 . Different lowercase letters indicate significant difference (p<0.05 ).