中文摘要：

人工施氮量是影响烟叶中游离氨基酸含量的重要因素,而后者很大程度上影响着烟叶的品质和风味。为了解不同施氮量对烟叶中游离氨基酸含量的影响,在大田条件下通过设置施氮量为60 kg/hm^2、90 kg/hm^2和120 kg/hm^2 3个施氮水平进行处理,用分光光度法和气相色谱-质谱联用法分析,研究了不同施氮水平对游离氨基酸含量以及脯氨酸和苯丙氨酸代谢关键酶及其基因表达的影响。结果表明,随施氮水平的不同,烟叶中总游离氨基酸、脯氨酸和苯丙氨酸含量随施氮水平增加而增高;而亮氨酸、异亮氨酸、丙氨酸和4-氨基丁酸含量在施氮水平为60 kg/hm^2时最高。脯氨酸代谢相关酶和苯丙氨酸代谢相关酶活性均随施氮水平升高而增强,其基因相对表达量也随之上调。上述研究结果表明施氮水平可显著影响烟叶中游离氨基酸含量、种类及其代谢过程。

英文摘要：

Nitrogen fertilizing level plays an important role in content of free amino acids, which, to a great extent, is related to quality and flavour of tobacco leaf. To investigate the effects of different fertilizing levels on free amino acids as well as proline and phenylalanine metabolism in tobacco leaves, tobacco plants were grown in the field in three treatments of different nitrogen fertilizing levels （60, 90 and 120 kg/hm^2）, respectively. Data were detected by spectrophotometry and gas chromatography coupled with mass spectrometry. The results showed that the total content of free amino acids, proline and phenylalanine enhanced with the increase of the nitrogen fertilizing level; whereas, the content of leucine, isoleucine, alanine and 4-aminobutyric acid reached the upmost level of 60 kg/hm^2 nitrogen fertilizing. The activity and gene expression of proline metabolism-related enzyme and phenylalanine metabolism-related enzymes increased as nitrogen level rose. These results indicated that nitrogen fertilizing levels could significantly influence the contents, the species and the metabolic ways of free amino acids.