Abstract: In order to investigate the law of membrane lipid peroxidation  in the main veins of flue-cured tobacco during maturation, and to clarify the mechanism of aging of main veins, flue-cured tobacco varieties ‘K326’ and ‘Yuyan 6’ were used as experimental materials to determine the content of reactive oxygen species (O^2-, H₂O₂), malondialdehyde (MDA) and senescence-related genes (NtCP1, NtCP2) expression, and combined with NBT staining results to reveal the ripening and scenescence mechanism of main veins of flue-cured tobacco. The results showed that the variation trends of the content of active oxygen and MDA in the main vein were basically  same, all increased with the maturity of tobacco. With the development of maturity, the expression of NtCP1 gradually  increased, and the expression of NtCP2  first increased and then decreased, until it was lower than the unripe stage. Correlation analysis showed that the correlation between O^2-, H₂O₂and MDA content was high, and there was a  significanly positive correlation between NtCP1 expression and the content of O^2-, H₂O₂ and MDA, and a negative correlation between the expression of NtCP2 and the content of O^2-, H₂O₂ and MDA. In conclusion, during the maturity of tobacco leaves, the active oxygen substances and MDA in the main vein were gradually accumulated, and the expressions of senescence related genes were also greatly affected. The research results provided a theoretical basis for the membrane lipid peroxidation in the main vein during the maturity of tobacco leaves.

Key words: flue-cured tobacco, main vein, maturity, reactive oxygen species, gene expression

摘要： 为了探究烟叶成熟和衰老过程中其主脉中的膜脂过氧化规律，明确主脉衰老机理，以烤烟品种‘K326’和‘豫烟6号’为试验材料，测定分析烤烟主脉中活性氧物质（O^2- 、H₂O₂）和膜脂代谢产物丙二醛（malondialdehyde，MDA）含量及衰老相关基因（NtCP1、NtCP2）的表达，并结合NBT染色结果来分析烤烟主脉的成熟衰老机理。结果表明，烤烟主脉中的活性氧物质和MDA含量在烟叶的成熟过程中的变化趋势基本一致，均随着烟叶成熟度的增加而逐渐上升。随着烤烟成熟衰老的推进，NtCP1基因表达量逐渐上升，NtCP2基因的表达量呈先上升后下降的趋势，直至低于未熟时期。相关分析表明，O^2- 、H₂O₂和MDA含量之间的相关性较高，且NtCP1表达量与O^2- 、H₂O₂和MDA含量之间呈极显著正相关关系，NtCP2表达量与O^2- 、H₂O₂和MDA含量之间呈负相关关系。综上所述，在烟叶成熟过程中，其主脉中的活性氧物质和MDA是逐渐积累的，衰老相关基因的表达与烟叶的成熟度也密切相关。研究结果为烟叶成熟过程中主脉的氧化衰老规律研究提供理论依据。

关键词: 烤烟, 主脉, 成熟度, 活性氧, 基因表达