采用0.2、0.5、1.0和1.5mmol·L-1的硝普钠(SNP)处理3年生‘早钟6号’枇杷幼苗,以喷清水为对照(CK),于-3℃低温胁迫处理6h后在25℃下培养4d,测定恢复0、1和4d时叶片非酶抗氧化物质和抗氧化酶活性的变化.结果表明:与CK相比,经SNP处理的枇杷叶片过氧化氢(H2O2)含量降低,还原型谷胱甘肽(GSH)和抗坏血酸(AsA)含量及抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、脱氢抗坏血酸还原酶(DHAR)和单脱氢抗坏血酸还原酶(MDAR)活性升高.低温处理后恢复4d时,经0.5mmol·L-1SNP处理的枇杷叶片H2O2含量下降至CK的75.53%,而GSH和AsA含量分别比CK增加了29.12%和23.40%,APX、GR、DHAR和MDAR活性分别比CK增加了50.0%、44.4%、49.53%和62.68%.适当的外源NO处理可提高枇杷叶片的抗氧化系统活性,减轻细胞在低温胁迫下的损伤,其中以0.5mmol·L-1的SNP处理效果较理想. The seedlings of 3-year-old ’Zhongzhong 6’ were treated with sodium nitroprusside (SNP) at 0.2, 0.5, 1.0 and 1.5 mmol·L-1, and sprayed with water as control (CK) The results showed that compared with CK, the content of hydrogen peroxide (H2O2) in leaves of loquat treated with SNP was significantly higher than that of CK Reduced glutathione (GSH) and ascorbic acid (AsA) content, ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) and monodehydroascorbic acid The content of H2O2 in Loquat leaves treated with 0.5mmol·L-1 SNP decreased to 75.53% of CK while the contents of GSH and AsA increased by 29.12% and 23.40% respectively compared with CK %, APX, GR, DHAR and MDAR activities increased by 50.0%, 44.4%, 49.53% and 62.68%, respectively, compared with CK. Appropriate exogenous NO treatment increased the antioxidant system activity of loquat leaves and decreased the cell viability under low temperature stress Damage, of which 0.5mmol · L-1 SNP treatment effect is more satisfactory.