关键词: 烤烟, 主脉, 成熟度, 活性氧, 基因表达

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