关键词: 茉莉酸甲酯, 水杨酸, 链格孢菌, 防御酶, 多酚

Abstract: In order to explore the effects of plant growth regulators on the metabolism of antioxidant enzymes and polyphenols of tobacco, the mycelia growth of Alternaria alternate, under treatment with different concentrations of methyl jasmonate (MeJA) and salicylic acid (SA), the defense enzyme activities and polyphenol contents in tobacco mature leaves inoculated with and uninoculated with A. alternata were measured. The results showed that 1 mmol·L^–1 MeJA had the best inhibitory effect on A. alternata, and the inhibitory rate was more than 59%, followed by 3.5 mmol·L^–1 SA. The inhibitory effect of MeJA and SA on A. alternata was enhanced with the increase of growth regulator concentration. The treatment with 0.1 mmol·L^–1 MeJA and 2.5 mmol·L^–1 SA could induce SOD, POD and CAT defense enzymes activities in tobacco, and reduce H₂O₂ reactive oxygen content, while MeJA had better induction effect. Treatment with the two plant growth regulators and inoculating with the A. alternata could induce and improve the activities of PPO and PAL in tobacco leaves, which were related to polyphenol metabolism, but had little effect on tobacco polyphenols. The top three polyphenols with high content in mature tobacco leaves were chlorogenic acid, rutin and cryptochlorogenic acid.

Key words: methyl jasmonate, salicylic acid; Alternaria alternata, defense enzymes, polyphenols