The Influence Of Girdling After Topping On Distribution Of Nitrogen And Quality Of Upper Leaf Of Flue-cured Tobacco

Tobacco is an important economic crop whose harvest object is itsleaves. The intrinsic chemical composition reconciliation in Tobacco leaf is anessential index for tobacco quality. To ensure tobacco fully grow-up and inclusionenriching in mass cultivation, picking away inflorescence and adjacent young leavesthat means topping which has become an important measure when tobacco is inreproductive stage. Though topping can enrich inclusion and help tobacco fully grow,it also impair apical dominance of tobacco plant, causing root secondary development,enhancing uptake of soil nutrients, which does not accord with the best model fornutrient absorption of high quality tobacco leaf--rich when young, poor when old.Especially in later growing stage, it intakes mass nitrogen in the soil, leading to thick,stiff upper leaves, chemical into disharmony, and increasing the nicotine, also thesynthesis of the nicotine content in upper leaf quickly accumulating, reducing theusability of upper leaves. To solve this problem, this study adopts the method thatproceed different stem phloem ring cut in different time period after toppingcombined with picking away different tobacco part leaves to research nitrogenaccumulation distribution of tobacco plant’s impact on the quality of upper leaves.The results are as follows:1. Girdling processing, ten days after topping (area first)Ten days after topping, we respectively analyze the nitrogen and dry substanceaccumulation in tobacco’s root, stem and material accumulation amount in upper,middle and lower leaves. The result shows that the dry substance accumulationamount in upper, middle and lower leaves is lower than no girdling cutting ones tosome extent, especially the contents in upper leaves which really have a big differencein contrast. Besides, girdling ones’ root dry substance accumulation amount alsolower in comparison but tobacco stem’s is obviously higher. Nitrogen accumulation indifferent organs of tobacco plant has same trend with dry substance accumulation.The study for chemical material in upper and middle leaves shows that the nicotinechlorine content in the girdling upper and middle leaves are both much lower thanregular one but reducing sugar and total sugar amount of those are evidently higher in contrast with regular ones. All those can be concluded that tobacco leaves girdlingprocessing will weaken nitrogen metabolism of tobacco plant but reinforce the carbonmetabolism which accords with the high quality tobacco cultivation theory that whentobacco plant is in late growth stage, carbohydrate metabolism is stronger thannitrogen metabolism.2Girdling cutting and picking lower leaves, ten days after topping (area second)Girdling also picking the lower leaves, ten days after topping, the dry substanceand nitrogen content amount in tobacco plant are lower than comparison; the reducingrange is smaller than first area but same amount with area first. The dry substance andnitrogen accumulation in middle leaves are higher than contrast. To analyze middleand upper leaves girdling processing whether it restrains the try matter and nitrogenaccumulation. Yes, it does. However, restrainment can be weakened via picking thelower leaves. Girdling processing dry substance accumulation in root is higher thancomparison after girdling processing; nitrogen accumulation of tobacco in0to15days is lower than the girdling processed one; the nitrogen accumulation amount ishigher than no girdling one in15to20days processing; in10to20days girdlingprocessing, it’s going to be low. The dry matter or nitrogen accumulation in tobaccostem, girdling processing ones sharply higher than comparison. the chemical materialin upper and middle leaves except the chlorine content, reducing sugar content ingirdling processing middle leaves when compared do not reach obviously differentlevel; the others all reach the level. Moreover, the sugar alkali proportion is morecoordinate that means total sugar and reducing sugar content high, nicotine andchlorine contents low which can cultivate high quality, good usability tobacco.3Girdling cutting and picking middle and lower leaves, ten days after topping(area third)Girdling cutting also picking middle and lower leaves, ten days after topping. Thedry substance quickly accumulate in15to20days; nitrogen accumulation is lowerthan comparison in0to20days. Dry substance in girdling cutting root appearsnegative cumulative after0to5days then quickly accumulate. But dry substance ingirdling root is lower in comparison in0to20days all process. The conclusion is thatthe nitrogen accumulated content in girdling roots also same with area first. To analyzefrom the dry substance and Nitrogen accumulation circumstance of the whole tobacco plant, theupper leaves cannot obtain photosynthetic organic substance from the middle and the lower leavesand as there is no enough assimilation product to support, the upper leaves cannot fastly grow up after picking away the middle and the lower leaves; especially phloem girdling processingobviously restrains the normal growth and development of tobacco’ upper leaves and root, as wellNitrogen accumulation. The chemical material composition in upper leaves, girdlingprocessing reducing sugar and total sugar are largely higher than comparison; thenicotine chlorine massively decreasing that means all chemical material coordinationin girdling processing leaves is better than comparison. It also shows that girdlingprocessing obviously improves the intrinsic chemical composition of the tobaccoleaves so that it exserts a positive effect on improving the upper leaves quality.4Different girdling stages influence on flue-cured upper tobacco leaves andtobacco intrinsic chemical compositionChoosing girdling phloem in different growth stage after topping (T1girdling at onceafter topping; T2girdling, ten days after topping; T3topping and picking up lowertobacco leaves then girdling; T4toping and girdling before picking, CK no girdlingafter topping.) to test the dry matter accumulation and chemical composition offlue-cured upper tobacco leaves which result shows the dry substance accumulationamount of girdling flue-cured leaves is higher than comparison, especially the effectof T3process is most obvious.to analyze chemical composition, all shows thatgirdling processing evidently adds the total sugar, reducing sugar content and totalnicotine, chlorine which hugely reduce the bad chemical composition, adjustingtobacco leaves’ sugar nitrogen proportion so that enhance chemical compositioncoordination.Via comprehensive analysis, tobacco girdling, topping after ten days which canrestrain the dry substance and nitrogen’ quick accumulation. However, when theringed tobacco grow callus, the dry substance and nitrogen of tobacco will regainquick accumulation; especially the method to pick away the lower leaves, toppingafter ten days, which can obtain the best girdling processing effect. Besides, throughcombined analysis from different girdling period flue-cured tobacco, the conclusionshowing as below: topping also phloem girdling after picking the lower leaves, whichnot only can help the dry substance in upper leaves effectively increased, but also begood for adjusting and controlling the coordination of the intrinsic chemicalcomposition in tobacco so that it distinctly improves the upper leaves quality.