Abstract: In order to explore the best foliar spraying concentration of organic carbon fertilizer in the application of hydroponic lettuce，the effect of foliar spraying of different concentrations of liquid organic carbon fertilizer on the growth，quality and activities of enzymes related to carbon and nitrogen metabolism of lettuce was studied by setting 1 600，1 200，800 and 400 times liquid concentration levels with bolting resistant lettuce as the test material，and spraying water as the control．The results showed that spraying liquid organic carbon fertilizer on leaves could promote the growth of lettuce in hydroponic cultivation，and improve the activities of enzymes related to carbon and nitrogen metabolism．Among them，1 200 times treatment had the best eff ect．The plant height，maximum leaf length，maximum leaf width，fresh and dry weight of shoot and root，total chlorophyll content，VC content，sucrose phosphate synthase（SPS）activity，nitrate reductase（NR）activity，glutamine synthase（GS）activity，glutamate dehydrogenase（GDH）activity，glutamate synthase（GOGAT）activity，and nitrogen accumulation in shoot of lettuce were signifi cantly higher than those of the control．

Key words: lettuce, liquid organic carbon fertilizer, growth, quality, carbon and nitrogen metabolism enzymes

摘要： 为探究有机碳肥在水培叶用莴苣应用上的最佳叶面喷施浓度，以全年耐抽薹生菜为试材，设置1 600、1 200、800、400倍液浓度水平，以清水作对照，研究叶面喷施不同浓度液态有机碳肥对叶用莴苣生长、品质以及碳、氮代谢相关酶活性的影响。结果表明：叶面喷施液态有机碳肥对水培叶用莴苣的生长具有促进作用，提高了碳、氮代谢相关酶的活性。其中，1 200倍液处理的效果最佳，叶用莴苣株高、最大叶长、最大叶宽、地上部及根鲜干质量、总叶绿素含量、VC含量、蔗糖磷酸合成酶（SPS）活性、硝酸还原酶（NR）活性、谷氨酰胺合成酶（GS）活性、谷氨酸脱氢酶（GDH）活性、谷氨酸合成酶（GOGAT）活性、地上部氮积累量均显著高于对照。

关键词: 叶用莴苣, 液态有机碳肥, 生长, 品质, 碳、氮代谢相关酶