The Effects Of The Interactions Of The Nitrogen And Phosphorus On The Carbon And Nitrogen Metabolism And The Quality Of Flue-cured Tobacco

The effects of N, P fertilizer interaction to the key enzyme activity of carbon and nitrogen metabolism, and the changes of content of nitrogen compounds and carbon compounds were studied during the growth and development of flue-cured tobacco leaves. The content of nitrogen compounds and carbon compounds, neutral aroma, as well as the contents of petroleum extracts in cured tobacco leaves were also studied. The Grey relationship analysis of the key enzyme activity of carbon and nitrogen metabolism and the content of chlorophyll with the content of main nitrogen-containing compounds and carbon compounds were analyzed during the process of leaf growth and development. The results showed that:1. The height during the flue-cured tobacco were all shown increased with the increase of nitrogen application rate. The height of high-nitrogen (N3) treatment was higher at the rosette stage,vigorous growing,stage budding stage and maturing stage, the more nitrogen application, the more fertility of the soil after the rosette stage which can promote the growth of tobacco; The stem, the largest leaf was shown with the increase of P application. The number of effective leaves P2, P3, P4 was significantly higher than P1 treatment in low-nitrogen (N1) level in growth and development of the tobacco, but not obvious difference at handling of nitrogen (N2) or high nitrogen (N3) level.2. With equal K fertilizer rate, the tendency of the nitrate reductase (NR) activity was declined at rosette stage and vigorous growing stage; the decline of invertase (INV) activity was shift to an earlier date; amylase activity was increased at later stage and the chlorophyll contents of tobacco leaves were increased faster at earlier stage. The nitrate reductase (NR) activity was increased at earlier stage under the phosphorus application of 45-105kg/ hm²;the application of phosphorus at the rate of 105 kg/ hm² and 135 kg/ hm² has no effect on the invertase (INV) activity; the more application of phosphorus can greatly increase amylase activity at later stage. Under the nitrogen level of 60 kg/ hm², the content of chlorophyll was increased at the application of phosphorus of 45-105kg/ hm². In conclusion, the transformation of carbon and nitrogen metabolism was timing at mid level of nitrogen which can fulfill the high quality tobacco growth.3. The content of total nitrogen, protein, nicotine and total sugar increased with increased nitrogen application. The content of reducing sugar was at peak value in the vigorous growing stage which the nitrogen application rate was 60 kg / hm² ,but when the nitrogen application was 30kg / hm² and 90 kg / hm² ,the peak value was in the budding stage. The starch reduced when the nitrogen application was increased. The N rate of 60 kg / hm² and the P with the amount of 105 kg / hm² has interaction, which the content of nitrogen compounds were higher, which was more conducive to the absorption of the leaves of nitrogen. With the phosphorus increased, the accumulation of the total sugar and reducing sugar in tobacco leaves was promoted the latter growth stage.4. The correlation of the total nitrogen, protein content and nitrate reductase activity was the biggest; nicotine content associated with the chlorophyll content was maximum; total nitrogen, protein, nicotine content associated with amylase activity was in the smallest degree; the association of the reducing sugar and starch content with the invertase activity was maximum; the association of total sugar content with chlorophyll content was in the greatest degree.5. Increase in nitrogen application rate can be significantly increased in content of total nitrogen, protein, nicotine. The total sugar and reducing sugar in cutter leaves and bottom leaves was declined with the increased nitrogen application. The starch content was higher in lower nitrogen (N1) treatment; under the nitrogen application of 60 kg/hm² and 90kg / hm², the total sugar in cutter leaves, the reducing sugar in upper leaves and cutter leaves was increased in the amount of phosphorus at 45-105kg / hm² (P1 P3 processing) level . The increased phosphorus application could increase the starch content of cured tobacco in the range of 45-105kg / hm². The correlation of starch with total nitrogen and protein was significantly negative, was highly significant negative correlation with the content of nicotine.6. The effect of different nitrogen fertilizer treatments on the content of petroleum extracts in cured tobacco leaf was that N2 treatment was highest. When the amount of nitrogen application was 30 kg/hm², the content of petroleum extracts was increased with the more P application. The content of petroleum extracts was increased with the more P application in the range of 45-105kg / hm² (P1 P3) under the 60 kg/hm² in and 90kg / hm² nitrogen application.7. High-nitrogen (N1) can be improved to deal with the content of phenylalanine. With the increasing nitrogen application rate, the content of products degraded by carotene and Neoplytadiene had increased in upper leaves. The content of browning reaction substance was higher at the nitrogen application of 60 kg/hm². The content of products degraded by cembrane was higher at the nitrogen application of 30 kg/hm². Phenylalanine content was increased with the increase of phosphorus in low-nitrogen (N1) level; the content of products degraded by carotene was increased with the more P application in the range of 45-105kg / hm² under the low-nitrogen (N1) and middle nitrogen (N2) level. The content of browning reaction substance was increased with the more P application in the range of 45-75kg / hm² (P1 P2 treatment). The content of products degraded by cembrane was increased with the more P application in the range of 45-75kg / hm² (P1 P2 treatment). The content of neoplytadiene was increased with the more P application under the low-nitrogen (N1) level; when the P application was 105kg/ hm² and the nitrogen application was in the range of 60-90 kg/ hm², the content of neoplytadiene could be increased.8. Overall, when the N:P₂O₅:K₂O was 1:1.75:3.375 and the nitrogen application was 60 kg / hm² was propitious to the growth of flue-cured tobacco and quality of cured tobacco leaf.