| Nitrogen is one of the three essential nutrients for the growth and development of tobacco,which has an important impact on the growth and development of tobacco,the formation of yield and quality.In order to explore the effects of different nitrogen source forms on the growth,development,physiological and biochemical characteristics of flue-cured tobacco,three different nitrogen source treatments,ammonium sulfate,urea and calcium nitrate,were selected as materials for pot experiment.The main results are as follows:1.Effects of different forms of nitrogen sources on Main Agronomic Characters of tobacco plantsThe effects of 45-75 days after transplanting on plant height,stem circumference,leaf number and maximum leaf area of flue-cured tobacco showed that ammonium sulfate treatment was greater than other treatments.2.Effects of different forms of nitrogen sources on dry matter accumulation of tobacco plants90 days after planting,the fresh weight of roots,stems and largest leaves of tobacco plants were treated with ammonium sulfate > urea > calcium nitrate.The fresh weight of roots,stems and leaves treated with ammonium sulfate was 2.1%,-8.0%,16.4% higher than that treated with urea,and 11.6%,3.3%,32.9% higher than that treated with calcium nitrate.The effects of different treatments on the ratio of roots,stems and largest leaves were all treated with ammonium sulfate > calcium nitrate The fresh weight of root,stem and leaf of treated ammonium sulfate was 15.7%,2.7% and 7.0% higher than that of treated urea,and8.5%,-2.0% and 18.7% higher than that of treated calcium nitrate.3.Effects of different forms of nitrogen sources on root volume of tobacco plantsThere was no significant difference between the treatment of calcium nitrate and the treatment of urea(P < 0.05).The root volume of the treatment of ammonium sulfate was7.3% and 4.6% higher than that of the treatment of calcium nitrate and urea,respectively.4.Effects of different nitrogen source forms on relative chlorophyll content and net photosynthetic characteristics of leavesFrom 0 to 75 days after transplanting,the relative chlorophyll content(SPAD value)of leaves was treated with ammonium sulfate > treated with urea > treated with calcium nitrate;from 75 days after transplanting,the effects on net photosynthetic rate,stomatal conductance and transpiration rate of leaves were treated with ammonium sulfate > treated with urine >treated with calcium nitrate,and the treatment of calcium nitrate had the best effect on the increase of intercellular CO2 concentration;among them,the treatment of calcium nitrate had the best effect on the increase of intercellular CO2 concentration The net photosynthetic rate of ammonium sulfate was 15.3% and 16.7% higher than that of urea and calcium nitrate respectively.5.Effects of different nitrogen source forms on protein content and proportion in leavesThe protein content of the three different parts of the leaf tip,the middle part of the leaf and the base of the leaf were all affected by the treatment of ammonium sulfate,the treatment of calcium nitrate,the treatment of urea,and the treatment of urea was significantly lower than the treatment of ammonium sulfate,but there was no significant difference between the treatment of calcium nitrate and the treatment of urea(P < 0.05);the protein content of different parts of the same leaf with different treatment was all shown as the tip > the treatment of urea Leaf middle > leaf base.6.Effects of different treatments on the content of N,P and K in tobacco plants and the proportion of N,P and K in roots,stems and leavesThe effect of ammonium sulfate treatment on the nitrogen content of tobacco plants was the best,which was 4.9%-11.4% higher than that of other treatments;the effect on the phosphorus content of tobacco plants was the best,which was 7.2%-11.4y higher than that of other treatments;the effect on the potassium content of tobacco plants was the best,which was 7.1%-13.2% higher than that of other treatments.The results showed that the proportion of N,P and K in different parts of tobacco plant was leaf > stem > root.7.Effects of different forms of nitrogen sources on enzyme activities of tobacco leaves1)Nitrate reductase(NR)activity,0-60 days after transplanting,the effects of different nitrogen source treatments were ammonium sulfate > calcium nitrate > urea,the application of nitrogen source ammonium sulfate was significantly higher than other treatments;75 days after transplanting,the NR activity of nitrogen source calcium nitrate was significantly higher than that of other treatments(P < 0.05).2)Glutamine synthetase(GS)activity,0-60 days after transplanting,the effect of different nitrogen source treatments was urea >ammonium sulfate > calcium nitrate;75 days after transplanting,there was no significant difference among three different nitrogen source treatments(P < 0.05).3)Urease(UE)activity showed that urea > ammonium sulfate > calcium nitrate before 45 days of transplanting,and urea > ammonium sulfate after 45 days of transplanting.In conclusion,the results showed that: during the field growth of flue-cured tobacco,the application of NH4 + had the best effect on the growth and development of roots,stems and leaf organs,and the dry matter accumulation of roots and leaves,the application of urea nitrogen had the best effect on the dry matter accumulation of stems,the application of ammonium nitrogen had the best effect on the protein content of leaves,and the activity of NR had the best effect on ammonium The response of as N was the highest,and the application of urea N was the best for the improvement of GS and UE activity.Therefore,in the production of flue-cured tobacco,the best nitrogen form for the growth,development and material accumulation of flue-cured tobacco is ammonium nitrogen. |
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