Abstract: In order to explore the impact of different nitrogen application rates on flue-cured tobacco plastid pigment content and metabolic pathway genes, this paper carried out studies on the plastid ultrastructure, plastid pigment contents, and plastid pigment metabolism-related gene expression patterns at middle leaf ripening stage under different nitrogen application rates by using electron microscopy, fluorescence quantitative PCR and liquid chromatography. The results revealed that high nitrogen application could markedly promote the chloroplast development and plastid pigment accumulation. Notably, the number and volume of osmiophilic granules and starch increased along with the increase of nitrogen application rate, while the number of thylakoid lamellas increased as well. Analysis of pigment metabolism-related gene expression patterns revealed that the transcript levels of PSY and CHL were adjusted and controlled by nitrogen, and the expression was inhibited at high nitrogen level, indicating PSY and CHL played crucial roles in metabolic pathway of plastid pigment.

Key words: tobacco, nitrogen application rate, plastid pigment, gene, ultrastructure

摘要： 为探讨不同施氮水平对烤烟质体色素含量和代谢途径基因的影响，通过使用电镜技术、荧光定量PCR和液相色谱法，研究了在不同施氮水平处理条件下，中部叶成熟过程中的叶绿体超微结构，质体色素含量和质体色素代谢关键基因的表达模式。结果表明:随着施氮量的增加，叶绿体被膜上的嗜锇颗粒增多增大，类囊体片层的数量增加，淀粉颗粒数量增加，体积增大；施氮量的增加处理可促进叶绿素和类胡萝卜素的合成，进而促进质体色素的合成;质体色素代谢相关基因的表达模式分析显示，PSY和CHL基因的转录水平受氮素调控，且在高氮水平下抑制表达，是质体色素代谢途径中的关键基因。

关键词: 烟草；施氮量；质体色素, 基因；超微结构