The ability and dynamics of accumulation of Se in different flue-cured tobacco varieties were analyzed.The results indicated that:①Among different flue-cured tobacco varieties,K326 showed strong ability of accumulating Se,and hongda showed weak ability of accumulating Se relatively.During the development and growth of flue-cured tobacco,the content of Se in zhongyan 103,yunyan 87 showed the changeable trend of "continuous rising-decline",and that in hongda,K326,NC82 showed the trend of " declinerising -decline".②Se-enriched soil through spiking promoted the accumulation of Se in upper leaves.In contrast with other tobacco varieties,zhongyan 103 and yunyan 87 had stronger ability to utilize Se.Under the condition of Se-enriched soil through spiking,the dynamics of accumulation of Se in hongda,K326, NC82 had been changed and hongda,K326,NC82 were more sensitive to Se fertilizer than other varieties.

The optimum application rate of tianyuan living-bacteria solution on flue-cured tobacco growth was investigated by large scale field experiments.The result showed that the decomposition of organic matter in composting accelerated after application of microbial agents.Application of 1 000 mL/667m2 microbial agents could increase the soil available K content by 125.00%.500 mL/667m2 enhanced contents of available nitrogen by 91.61% and available P by 121.62% in soil.The soil density decreased and the degree of soil maturation was accelerated.Application of 2000 mL/667m2 microbial agents could decrease the soil density by 12.31%.Application of 1 000 mL/667m2 microbial agents could extremely increase weight of dry root 73.61%.By applying 1 000 mL/667m2 microbial agents,the indices of yield per 667 m2,production value,mean price and first-class tobacco leaves proportion increased to 26.32%,59.33%,26.59% and 5.66%,respectively.The score of aroma quantity and quality increased.The availability of tobacco leaf enhanced.In conclusion,application of 1 000 mL/667m2 microbial agents was the optimized volume to flue-cured tobacco production.

The characteristics of polyphenols in Hubei flue-cured tobacco(K326) and the relationship between it and altitude in Hubei were analyzed.The results indicated that:(1)The average content of polyphenols was 37.63 mg/g and the content gradually increased with tobacco leaves from top to bottom.(2) The correlation analysis between polyphenols and altitude indicated that the polyphenols content in C3F and X2F grades significantly increased with altitude rising.(3) Altitude and tannic,chrysatropic acid,flavonoid,polyphenol could be classified into 3 groups by Cluster analysis.When B2F,C3F and X2F grades under the altitude range from 1050m to 1200m,the contents of polyphenols were higher.