中文摘要：

用香豆素类化合物（前胡香豆素Ⅲ、前胡香豆素Ⅱ、北美芹素）,每种化合物分别设1、5、10、50、100mg/L处理早稻组合培两优500,研究在低温（5±1）℃胁迫下香豆素对水稻幼苗的成苗率、茎叶干重、根干重以及防御酶活性、可溶性蛋白质含量、叶绿素含量和游离脯氨酸含量的影响.结果表明,3种香豆素化合物处理均能使水稻幼苗的成苗率、茎叶干重、根干重显著高于对照（清水）,且50mg/L处理时效果最佳.50mg/L的香豆素化合物处理均使水稻秧苗在低温胁迫下的过氧化物酶、超氧化物歧化酶、过氧化氢酶活性、可溶性蛋白质含量和叶绿素含量升高,游离脯氨酸积累增加.

英文摘要：

The effects of coumarins have been studied on seedling rate,stem and leaf dry weight and root dry weight of the tested rice,as well as defense enzymes,soluble protein content,chlorophyll content and proline content with coumarins （peucedanocoumarin Ⅲ,PeucedanocoumarinⅡ,pteryxin） （1,5,10,50,100 mg/L）.The coumarin compounds have been used to treat the early rice combination Peiliangyou500 with low temperature stress of（5±1） ℃.The results showed that three coumarin compounds could make seedling rate,stem and leaf dry weight and root dry weight of the tested rice significantly higher than control,and the effect of 50 mg/L was the best.50 mg/L coumarin compounds made peroxidase,superoxide dismutase,catalase active and soluble protein content,chlorophyll content.Proline accumulation also increased under low temperature stress.