Nitrogen Metabolic Differences Of Flue-cured Varieties And Their Impact On Tobacco Aroma Precursors

In order to explore the effects of Nitrogen metabolic differences offlue-cured tobacco varieties in the formation of tobacco aroma precursors, the use ofpot and field fertilization experiment,measured nitrogen metabolites and relatedenzyme activities in the maturation of10th Henan tobacco, Tobacco100, NC89andK326under different nitrogen levels,and measured the content of the aromaprecursors of arytenoids, polyphones and petroleum ether extract at the same time.1.Under different nitrogen levels, the presence of nitrogen metabolism varies betweenspecies, and the difference mainly in the recycling of nutrients nitrogen and nitrogendegradation and transferred two aspects.the higher the NR and GS activity is, thestronger the nitrogen absorption and assimilation ability, the higher the solubleprotein and total nitrogen content and the lower the leaf NH4+concentration; In theaging period, GS activity decline, GDH activity is high, the nitrogen assimilationability is abate, the quantity of the nitrogen nutrient degradation increase, promote theaging; The compensation point of ammonia is low, ammonia volatilization quantity islittle, less nitrogen retransfer,the nitrogen use efficiency is high. The difference ofthe activity of nitrogen metabolism related enzyme such as GS, GDH of Varietiesdetermines the way of nitrogen transformation and transfer rules, It is an importantfactor leading to metabolic differences between genotypes nitrogen.2.In the period of Arytenoids accumulation, three carotenoids content of nitrogentreatment is N3> N2> N1, after that the carotenoid content under high nitrogen leveldecreased, but still significantly higher than that of low nitrogen levels. Underdifferent nitrogen levels, the percentage of Carotenoids accumulation and degradationvaries. The presences of varieties is YuYan10> ZhongYan100> NC89> K326.With the increase of nitrogen application carotenoids accumulation and degradation ofeach type were significantly increased. And carotenoids degradation reach themaximum amount in the leaf age50~70d, leaf GS activity decline sharply at thesame time. 3.With leaf senescence, The content of polyphenol exhibited decreased after an initialincrease reached the maximum in the leaf age of70d,then decline about20d beforeclose to tobacco mature harvest. In the leaf age40d, with the increase of nitrogenapplication,the content of polyphenol declined slightly after rising first, no significantdifference between high nitrogen and moderate levels nitrogen treatments; In theleaf age50~70d, the polyphenols content of YuYan10and NC89fell slightly afterrose first with the increase of nitrogen application, along with ZhongYan100andK326increase; In the leaf age80d, polyphenol content increased with the increase ofnitrogen application increased. Thus, polyphenol content differences betweenvarieties, and polyphenol content at different times in response to different amounts ofnitrogen.4. Along with the advancement of growth, in leaf age40-70d, petroleum etherextract of all varieties showed a growing trend, and with the increase of nitrogenapplication it increases first and then decreased, high nitrogen and moderate levelsnitrogen have no significant difference; In the leaf age70-80d,the performance ofpetroleum ether extract content of all varieties is different, and YuYan10and NC89petroleum ether extract content increased with the increase of nitrogen applicationincreased, the petroleum ether extract content of ZhongYan100and K326reducedafter rising first with the increase of nitrogen application, high nitrogen and moderatelevels nitrogen have no significant difference.The accumulation of petroleum etherextract between varieties, YuYan10> NC89> ZhongYan100> K326. Thus, theincrease of nitrogen application is conducive to the accumulation of petroleum etherextract in maturity, but there are differences between varieties.5.The correlation analysis of carotenoids, polyphenols, petroleum ether extractcontent,nitrogen metabolites and related enzyme activity shows:the early vigorousnitrogen metabolism of flue-cured tobacco is beneficial to the formation of thecarotenoids, and the late weakening of nitrogen metabolism is in favor of theformation of carotenoids;In the flue-cured tobacco maturity, vigorous nitrogenmetabolism promote the accumulation of petroleum ether extract, while restraine theformation of polyphenols. the strength of the nitrogen metabolism affects the theformation of aroma precursors such as carotenoids, polyphenols and petroleum etherextract. in order to increase the content of aroma precursor material degradationproducts, the varieties response to nitrogen and the characteristics of nitrogen metabolism should be taken into consideration. To choose the appropriate nitrogenapplication and regulation of tobacco nitrogen metabolism for different varieties isvery important to tobacco aroma precursors and the formation of the aroma substance.