中文摘要：

以广泛种植的2个黄瓜品种＂长春密刺＂和＂水果黄瓜＂为试材,叶面喷施0.30%、0.60%、0.90%硝酸铵,研究了不同浓度硝酸铵对幼苗鲜质量、叶绿素含量、渗透调节物质及酶活性等生理指标的影响,为有效且合理地施用氮肥提供参考依据。结果表明：喷施硝酸铵可提高2种黄瓜幼苗的鲜质量,对叶绿素a含量影响不大,促进叶绿素b含量和叶绿素总量的增加;随着喷施硝酸铵浓度的增大,可提高2种黄瓜的游离脯氨酸含量,降低可溶性糖含量,对可溶性蛋白质含量影响不明显;随着喷施硝酸铵浓度的增大,2种黄瓜的超氧化物歧化酶（SOD）活性变化趋势均为先增后降,而过氧化氢酶（CAT）活性变化趋势则呈现出先降后升,但较对照差异均不显著;＂长春密刺＂和＂水果黄瓜＂的叶面喷施硝酸铵最适浓度分别是0.30%和0.60%。

英文摘要：

In order to using nitrogen effectively and reasonablely,two widely cultivated cucumber cultivars‘Changchunmici＇and ‘Fruit cucumber＇were used as experimental materials,the influence of fresh weight,chlorophyll content,osmotic regulation substances,the enzyme activity and so on after spraying 0,0.30%,0.60%,0.90% NH_4NO_3 on leaves were studied.The results showed that spraying ammonium nitrate could improve the two kinds of cucumber seedling fresh weight,little influence on chlorophyll a content,total chlorophyll and chlorophyll b content were increased.With the increase of spraying ammonium nitrate concentration,improved the free proline content of two kinds of cucumber,reduced the content of soluble sugar,no obvious effects on soluble protein content.With the increase of spraying ammonium nitrate concentration,both SOD activity change trend of cucumber were first increased,while the CAT activity change trend showed a fall after rise first,but the differences were not significant than CK.The optimal spraying NH_4NO_3 of‘Changchunmici＇and‘Fruit cucumber＇respectively were 0.30% and 0.60%.