Absorption And Utilization Of Stable Isotope¹⁵N By Flue-cured Tobacco

Different sources and different forms of nitrogen uptake distribution lawof flue-cured tobacco in medium aroma style and full aroma style producing areas istested with15N labeled in Luzhou city,Sichuan province and Pingdingshan city,Henan province from2010to2011.The main results as follows:1:The total nitrogen in different organs of flue-cured tobacco showed the law ofleaf> stem>root in different growth stages, and which in most upper leaves, lowerleaves at least in different parts of leaves. Tobacco on nitrogen absorption peakconcentration in40to60days after transplanting, after topping to mature before thisperiod of tobacco plant nitrogen absorption rate decreased obviously and to enter theharvest period after the basic no longer absorption and accumulation of nitrogenwhich showed that the entire nitrogen accumulation of tobacco before toppingtreatment. The supply of nitrogen fertilizer must be fully in early stage of tobacco, thenitrogen absorption peak was40to60days after transplanting and the nitrogen supplycapacity of soil decided that tobacco nitrogen can be sufficient in this period, thenitrogen which come soil should be control after topping treatment to make sure themature of leaf was normal.2:The nitrogen mainly absorbed by tobacco which come from soil relative tofertilizer nitrogen, the ratio of nitrogen accumulation amount which come from thesoil to total nitrogen in tobacco were higher than50%in different growth stages and itincrease with the growth stage forward.3: The fertilizer nitrogen uptake and accumulation of flue cured tobacco nitrogenfrom base fertilizer in different growth stage, but the top-dressing nitrogen utilizationrate was higher than that of base fertilizer nitrogen. Reduced the rate of basal nitrogenapplication and increased the rate of top dressing could increase the efficiency offertilizer nitrogen and reduce the rate of soil nitrogen.4: The absorption of nitrate nitrogen far more than ammonium nitrogen which fromfertilizer nitrogen in flue-cured tobacco and the ratio of nitrate nitrogen to totalnitrogen was higher than that of ammonium nitrogen in different organs of tobacco indifferent growth stage. The accumulation of ammonium nitrogen and nitrate nitrogen content had little difference in40days after transplanting, but the difference which inthem increase obviously with the tobacco came into the peak of nitrogen absorptionso the accumulation amounts of nitrate nitrogen far more than ammonium nitrogenand which was to say tobacco plant mainly absorb nitrate nitrogen in fertilizernitrogen.5: The accumulation of nitrogen which in upper leaf than other parts and it in thelower leaf at least when leaves maturity of tobacco. The accumulation of nitrogenwhich from soil nitrogen were far more than the nitrogen which from fertilizer whendifferent parts of leaves maturity, and the quality of tobacco leaves was mainlyaffected by soil nitrogen.6: Flue cured tobacco leaves in different positions in the mature time cumulativemainly from nitrogen fertilizer in fertilizer nitrogen and which of it accounts for theleaves of the proportion of the total cumulative nitrogen fertilizer reduce with therising of the position of leaf and all of them were below60%. The ratio of basalfertilizer nitrogen accumulation amount to fertilizer nitrogen which of the mostappeared in lower leaves and least in top leaves between different parts of leaves.7: The absorption of nitrate nitrogen was far more than ammonium nitrogen whenthe different parts of leaves of flue-cured tobacco maturity. The ratio of nitratenitrogen accumulation amount to total nitrogen was reduced with the rising of heposition of leaf and which of the most had been in lower leaves and least in top leavesbetween different parts of leaves.