Abstract: To investigate the effects of full-period plastic mulching on the quality and aroma metabolism of flue-cured tobacco in high-altitude and rainy tobacco-growing areas, a field experiment was conducted in Xingyi City, Qianxinan Prefecture, Guizhou Province. Two treatments were set up: Conventional film removal at 40 days after transplanting (CK) and full-period plastic mulching (FM). The main chemical components, sensory quality and metabolomic characteristics of C3F tobacco leaves were analyzed. The results showed that compared with CK, FM significantly increased the contents of reducing sugars, nicotine, potassium and total nitrogen in tobacco leaves, and highly significantly reduced starch accumulation, leading to more coordinated overall chemical composition. Sensory smoking evaluation indicated that FM significantly improved aroma quantity, aftertaste and other indexes, with the total sensory score increasing by 6.45% compared with CK. A total of 178 significantly differential metabolites were identified by metabolomic analysis, among which key aroma substances such as trans,trans-2,4-heptadienal, phenethyl alcohol, benzaldehyde, citral and (E)-3,7-dimethyl-2,6-octadienal were significantly enriched under FM treatment. Further Mantel analysis revealed that the differential changes of these key metabolites were significantly correlated with the variation patterns of sensory indexes including aroma quantity and aftertaste(P<0.05). In conclusion, full-period plastic mulching improved the aroma quality and sensory style of flue-cured tobacco in rainy tobacco areas by regulating and promoting the accumulation of key aroma metabolite profiles.

Key words: flue-cured tobacco, plastic mulching cultivation, sensory quality, metabolomics, aroma substances