关键词: 丛枝菌根真菌, 烤烟, 镉, 砷, 谷胱甘肽, 生理特性

Abstract: To understand the physiological adaptation mechanism of mycorrhizalized tobacco plants to heavy metal stress，a pot experiment which took the flue‑cured tobacco Yuyan No. 7 as marerial，was carried out to study the physiological characteristics of tobacco affected by inoculating（AM） and uninoculating（NM）arbuscular mycorrhizal fungi at different As and Cd levels（0，1，30 mg/kg），to explore the physiological mechanisms of microbial mitigation of Cd and As toxicity in flue‑cured tobacco，and provide some reference for safe production of flue‑cured tobacco.The results indicated that compared with CK（Cd=0 mg/kg and As=0 mg/kg），As stress had no effect on the infection and colonization of mycorrhizal fungi on tobacco plants，and Cd stress significantly reduced the infestation rate of arbuscular mycorrhizal fungi.With the intensification of Cd or As stress，shoot leaf area，photosynthetic parameters such as net photosynthetic rate（Pn），stomatal conductance（Gs），intercellular CO2 concentration（Ci），transpiration rate（Tr）and root morphological indexes such as total root length，root surface area and root volume of flue‑cured tobacco decreased in NM treatment，and the lowest was under 30 mg/kg stress，while the above indexes were improved by AM treatment.Inoculation with arbuscular mycorrhizal fungi could effectively promote the synthesis of glutathione（GSH），the shoot and root antioxidant of tobacco under heavy metal stress，and reduce the accumulation of Cd and As in the aerial part and roots of flue‑cured tobacco，and the Cd content of shoot and root in AM treatment under 30 mg/kg Cd stress was reduced by 40.55% and 23.19%，and the As content under 30 mg/kg As was reduced by 20.94% and 78.50%，respectively，compared with NM treatment. In a nutshell，inoculation with arbuscular mycorrhizal fungi can improve the developmental metabolism of tobacco under Cd and As stress，regulate the synthesis and secretion of GSH，and thus reduce the accumulation of Cd and As in tobacco plants.

Key words: Arbuscular mycorrhizal fungi, Flue?cured tobacco, Cadmium, Arsenic, Glutathione, Physiological characteristics