中文摘要：

游离氨基酸是烟叶中的重要化合物，它很大程度上影响着烟叶的品质和风味。为了解不同生长温度对烟叶中游离氨基酸的含量及其代谢的影响，通过人工气候室设置均温18．5℃、23．5℃和28．5℃3个动态气温条件，在烟叶从早期生长至成熟的整个时期进行不同生长温度处理，用分光光度法、气相色谱一质谱法和荧光定量PCR分析，研究了不同生长温度下总游离氨基酸含量和单个游离氨基酸含量的变化规律及对脯氨酸和苯丙氨酸代谢的影响。结果表明，不同生长温度对烟叶生长发育过程中游离氨基酸总量和单一游离氨基酸含量有明显影响。其中，随着烟叶生长发育的进行，所含游离氨基酸含量逐渐下降。在不同生长温度处理下，随生长温度升高总游离氨基酸含量下降；各游离氨基酸含量基本上也随生长温度的升高而降低。对脯氨酸代谢相关酶（P5CS，OAT，ProDH）活性以及苯丙氨酸代谢相关酶（PAL，C4H）活性及其基因表达的定量研究表明，其酶活性和基因表达的变化与含量变化的趋势一致。上述研究结果表明，随着烟叶的生长发育和成熟，其游离氨基酸含量逐渐降低，而较低的生长温度有利于烟叶维持较高的游离氨基酸水平。

英文摘要：

Free amino acids are important compounds in tobacco leaves, which affects the quality and flavour of tobacco leaves to a large extent. To investigate the effects of different growth temperature on the content and metabolism of free amino acids in tobacco leaves, tobacco plants were grown in phytotrons with three dynamic temperatures set as average 18.5℃, 23.5℃ and 28.5℃ from early growth stage to maturation stage of tobacco leaves. The change characteristics of the content of total free amino acid and single free amino acids content, and the metabolism of proline and phenylalanine were detected by spectrophotometry, GC-MS and real-time quantitative PCR in tobacco leaves under different growth temperature. The results showed that different growth temperatur had significant influence on the content of total amino acids and free amino acids during growth and development of tobacco leaves. Firstly, with the growth and development of tobacco leaves, the contents of total and single free amino acids decreased gradually; Secondly, the content of total free amino acids decreased with increasing temperature at different growth temperature. The content of free amino acids also decreased with the increase of temperature. The quantitative studies on proline metabolism-related enzymes （P5CS, OAT and ProDH） and phenylalanine metabolism-related enzymes （PAL and C4H） and their gene expression indicated that the changes of these enzyme activities and gene expression were consistent with their content changes. These above results suggested that with the growth and development and maturation of tobacco leaves, the content of free amino acids decreased gradually, and lower growth temperature was beneficial to maintain a higher level of free amino acids in tobacco leaves.