Study On Plant Type And Physiological Properties Of Flue-cured Tobacco In Chongqing Mountain Regions

The plant of flue-cured tobacco has an impotrant influence on growth and development of tobacco.The ideal plant type can not only improve the yield of tobacco,but also is an important basis of quality formation of flue-cured tobacco.Study on the plant type characteristics of flue-cured tobacco can provide theoretical guidance for the breeding of flue-cured tobacoo varieties or direct standard for the high-yield cultivation of flue-cured tobacoo.Taking Yunyan 97 as an example,a field experiement with two factors(nitrogen application rate and remained leaves number)was used to research plant type and physiological properties of flue-cured tobacco in Chongqing mountainous regions under different cultivation models.The main results are as follows:The plant type of flue-cured tobacco mainly had three dynamic changes in the whole growth period,including drum shape-long cylinder,drum shape-high deck and high deck-drum shape-high deck-long cylinder.The nitrogen application rate had influence on plant type of tobacco but did not reach significant level.The remained leaves number also had influence on plant type of tobacoo and one of the indexes of plant type characteristics reached significant level.The interaction of two factors on the plant type of tobacco had not significant influence.It indicated that remained leaves numnber had an important role on the formation of plant type of tobacco.The root dry weight per plant,stem dry weight per weight,leaf dry weight per plant,plant dry weight and root-shoot ratio of drum shape-long cylinder were the largest.So drum shape-long cylinder was more conducive to the dry matter accumulation of flue-cured tobacco and improvement of quality of tobacco leaf.The leaf area per plant,leaf area index,leaf area duration,specific leaf area,leaf area ratio,leaf weight ratio and relative growth rate of high deck-long cylinder were the largest.The specific leaf weight,photosynthetic productivity,crop growth rate,growth rate and net assimilation rate of drum shape-long cylinder were the largest.The leaf relative growth rate of drum shape-high deck was the best.Taken together,the group physiological properties of drum shape-long cylinder were the best.The total soluble sugar of high deck-long cylinder was more appropriate.It can coordinate nicotine.The amylase activity of high deck-long cylinder was more conducive to the accumulation of the amylum.And the glutamine synthetase activity of high deck-long cylinder was the highest.It was conducive to the absorption and transformation of inorganic nitrogen in flue-cured tobacco.The sucrose phosphate synthase activity,sucrose synthase activity and nitrate reductases activity of drum shape-long cylinder were the highest.The phenylalanine ammonia-lyase activity and polyphenol activity of drum shape-long'cylinder were more appropriate.It can get better quality of tobacco leaf.The protein content,peroxidase activity,superoxide dismutase activity and catalase activity of drum shape-high deck were the most suiTablele.It can improve the antioxidant capacity of Tableacoo and make tobacco grow normally.The potassium content,chlorine content and ratio of potassium chlorine of high deck-long cylinder were more appropriate.The nitrogen content,nicotine content and ratio of nitrogen to nicotine of drum shape-long cylinder were more appropriate.The reducing sugar content and sugar alkali ratio of drum shape-high deck were more appropriate.The all potassium content and chlorine content were lower than the suiTablele range.The ratio of potassium chlorine,reducing sugar content and sugar alkali ratio under three plant types were in the optimum range.The nitrogen content,nicotine content and ratio of nitrogen to nicotine of high deck-long cylinder and drum shape-long cylinder were in the optimum range.The chemical components of drum shape-long cylinder was the most consistent with the evaluation of chemical components coordination of tobacco leaf with different plant type.The chemical components of high deck-long cylinder was also coordinate.Taken together,the chemical components and quality of tobacco leaf of drum shape-long cylinder were better.The yield,output and proportion of superior tobacco of drum shape-long cylinder were the largest.And the average price of drum shape-high deck was the highest.Therefore,the flue-cured tobacco of drum shape-long cylinder can obtain higher yield,output and proportion of superior tobacco.Through comprehensive comparison,the ideal plant type of Yunyan 97 in Chongqing mountainous regions is drum shape-long cylinder.lt can obtain better yield and quality of flue-cured tobacco.