关键词: 烤烟, 赤霉素, 生长素, 脱落酸, GAI1基因, 化学成分

Abstract: In order to study the effects of exogenous GA3 and IAA on tobacco growth regulation and chemical composition, the mechanism of exogenous hormones and the optimal hormone concentration were explored based on hormone and gene levelsexplore. Taking the flue-cured tobacco variety NC71 as the experimental material, this paper set different concentration treatments of exogenous hormones to detect the changes of plant height, dry matter accumulation, hormone content, related gene expression and tobacco leaf quality. The results showed that exogenous GA3 could significantly increase the plant height and pitch of flue-cured tobacco, while the relative increase of exogenous IAA was less, and the dry matter quality of tobacco plants increased with the increase of GA3 concentration. Spraying different concentrations of exogenous GA3 and IAA increased the content of GA3 and IAA in shoot tip and reduced the content of ABA and the effect of 150 mg/L was the most obvious, the exogenous GA3 of 100 mg/L and the exogenous IAA of 10 mg/L were the second exogenous. GA3 significantly reduced the expression of GAI1 gene in tobacco, and IAA also reduced the relative expression of GAI gene, but the effect was relatively weak. The content of total sugar, reducing sugar and potassium in tobacco leaves sprayed with exogenous hormones increased, while the contents of total nitrogen, nicotine and chlorine decreased, and potassium in the condition of 100 mg/L exogenous GA3 combined with IAA. The ratio of chlorine to sugar and alkali was the highest, and the quality was better, so 100 mg/L exogenous GA3 and 10 mg/L exogenous IAA were sprayed 15 d after transplanting according to the principle of lessness. These results provided a basis for the application of exogenous growth regulators to flue-cured tobacco in the central part of Henan province tobacco area.

Key words: flue-cured tobacco, gibberellin, auxin, abscisic acid, GAI1 gene, chemical composition