Study On The Changes Of Physiological And Biochemical Indexes Of Yanbian Sun-cured Red Tobacco Cultivars In Field And During Curing Period

In this paper,the economic characters,photosynthetic characteristics,leaf tissue structure,physiological and biochemical indexes during the process of growth and modulation of different Yanbian sun-cured red tobacco varieties were compared by using the same cultivation measures and modulation methods in the same environment,in order to select high-quality varieties suitable for current planting requirements and cigarette industry needs.At the same time,the changes rule of main enzyme activity and chemical components in different varieties and parts of tobacco leaves during the curing stage were obtained,which laid a foundation for each variety to adjust the drying conditions,optimize the internal components of tobacco leaves,and achieve high-quality sun-cured tobacco.1.YanShai No.2(S2)grew fastest during the whole growth and development,so that S2 plant height was the highest.YanShai No.6(S6)and YanShai No.7(S7)grew faster in the later growth stage,Zi Laihong(S1)plant height was the lowest,other varieties were relatively high,S6 and S3 stems were thicker,S6,S3,S1 leaves were wide.According to the index of agronomic traits of 70 days after transplantation,the field performance from good to bad is as follows:YanShai No.6(S6),YanShai No.3(S3),YanShai No.2(S2),YanShai No.5(S5),ZiLaihong(S1),YanShai No.7(S7)and YanShai No.4(S4),respectively.2.At 45 days after transplanting,the best indexes of photosynthetic characteristics were S3 and S5,followed by S1,S2,S6 and finally S7.At 60 days after transplanting,the best indexes of photo synthetic characteristics were S2,S6 and S7,followed by S3,S4,S5 and finally S1.The chlorophyll content of each cultivar had little difference in the early stage of growth,and the degradation of S4,S5 and S7 was faster in the later stage.In tobacco leaf structure,the data of variety S3 were the best,followed by variety S6,and the worst was variety S5,while the tobacco tissue structure proportion of varieties S2 and S1 was better.3.During the whole growth and development process,the amylase activity of all varieties increased first and then decreased,and reached the highest level at the mature stage(70 days after transplanting).Among them,the amylase activity of S2 was the highest,followed by S1 and S6,and S7 was the lowest.The activity of invertase(INV)in tobacco leaves of all varieties decreased from bud stage to maturity stage,and then changed little and was relatively stable,among which S6 was the highest.Nitrate reductase(NR)activity began to decline in the rapid growth period(40 days after transplantation),while the activities of S2,S6 and S7 NR were relatively high.4.The activities of amylase in different varieties and different parts of tobacco leaves showed a downward trend during the whole modulation process,among which the activities of S1,S2,S4 and S5 were higher;The protease activity of some tobacco leaves increased first and then decreased,while the other part showed a decreasing trend.The upper leaves S1,S2,S5 and S6 had higher activity,and the middle leaves were higher in S1,S5,S6 and S7;The activity of polyphenol oxidase showed a decreasing-increasing-decreasing-increasing trend.The enzyme activities of S1 and S3 in the upper leaves were lower,and the activities of S2,S3 and S4 in the middle leaves were lower.On the whole,the changes of enzyme activity in leaves of the same part of different varieties were slightly different at the same time.and the changes of enzyme activities in upper and middle leaves were basically the same among different cultivars.5.The starch content of tobacco leaves of all varieties and all parts decreased rapidly at the early stage of modulation,and decreased slowly at the later stage..The total nitrogen and protein content decreased slowly in general,but there was a small fluctuation in the modulation process.The content of polyphenols and nicotine did not change obviously.6.The chemical composition of each variety was within a reasonable range.The protein content of S6 was the lowest,but the nicotine content of upper leaves was higher.The starch content of S2 was the lowest,but the protein content of S6 was the highest.Among the economic characters,S6 yield is the highest,S5 is the second,S2 is the lowest,S6 output value is the highest,S1 is the second,S5 is the third and S2 is the lowest.7.Based on the above results,In the main varieties of Yanbian sun-cured red tobacco,YanShai No.6 was the best,followed by Zi Laihong,YanShai No.3 and YanShai No.5.