Study On Physiological And Biochemical Characters Of The Flue-cured Tobacco Of Different Breeds In Seedling Period

In this paper, the physiological and biochemical characteristics of the flue-cured tobacco ofdifferent breeds in seedling period was researched by germinating seedling in water, by growingseedling in soil, and by another growing seedling under the different form of nitrongen atdifferent levels. In the test to seed germinating in water for 14 days by repeating three times, the12 different breeds of flue-cured tobacco was adopted, of Yunyan85, Yunyan202, V2, Yunyan317,MS Yunyan85, MS K326, K346, K326, Yunyan201, MS Yunyan87, Yunyan203 and Yunyan87, ofwhich germination vigor, germination percentrage, germination index and vitality index, root'slength and nicotine content were measured. Those breeds of flue-cured were adopted too, In thetest to growing seedling on soil by three water content levels of 75%, 55% and 35%, of whichleaves amount, leaves area, fresh weight, dry weight were measured in 5 leaves period. In thistest, the activeties of nitrate reductase,protein content, soluble sugar content and nicotine contentof three breeds of Yunyan201, Yunyan203 and MS Yunyan87 were measured in 8 leaves period.Inthe test to growing seedling under different the form of nitrogen at different levels,two breeds offlue-cured tobacco were adopted, Yunyan201 and MS Yunyan87,of which seedling tallness,leavesarea, fresh,weight, dry weight,chlorophyll content, activeties of nitrate reductase,protein content,soluble sugar content, vitality of root,Potassium content, nicotine content were measured.Variance analysis and correlation analysis were adopted basing on all of data measured.Every breeds' of seed's sprouting characteristics, every breeds' of seedling's biologicalspeciality, and every breeds' of seedling's physiological and biochemical characteristics aredifferent because of different breeds of flue-cured tobacco.It has referene worth for choicingbreeds to plant. Nicotine content of seedling for 14 days in germination period is differentbecause of different breeds of flue-cured tobacco, and is related their root length. But no nicotinewas measured in the seedling in 5 leaves and 8 leaves period.It is probable to control nicotinecontent in growing period because of nicontine content changing in seedling growing period offlue-cured. There are significiant differences in the activities of nitrate reductase, protein contentand soluble sugar content among different breeds of flue-cured tobacco. The activities of nitratereductase and protein content descend by warter concent descending in soil, but soluble sugarcontent is increased. It is in water content of 75% that the physiological and biochemical characteristics make the seedling of flue-cured tobacco growing better.The tobacco seedlings of different breeds show some different physiological andbiochemical characteristics under the different forms of nitrogen fertilizer at different levels, butshow their commonness that protein content are increased by different nitrogen fertilizer's levelsrising from 0 mmol/L to 50mmol/L, that chlorophyll content and root's vitality are increased bynitrogen fertilizer's levels rising from 0 mmol/L to 20mmol/L, that tobacco seedling's growth andsoluble sugar accumulation do not adapt to NO₃-N fertilizer very much but NH₄⁺-N orCONH₂-N so that soluble sugar content are increased by nitrogen fertilizer's levels rising from 0mmol/L to 40mmol/L except 50 mmol/L, that Potassium accumulation adapt to NO₃-N fertilizerbut NH₄⁺-N or CONH₂-N, and that the growth of tobacco seedling and the activities of nitratereductase adapt more to the nitrogen level of 10 mmol/L or so. In a word, NH₄NO₄ is a better sortof nitrogen of tobacco seedlings, of which the better level of application is 10 mmol/L or a littlemore than 10mmol/L.