Studies On Effect Of Nitrogen Supply To Flue-cured Tobacco Nutrition Uptake And Quality After Topping

Take the methods of water culture and potted plant, This paper studied the effects of different nitrogen level and NH4+/NO3- ratio treatments on flue-cured tobacco growing, nutrition uptake and quality in late life stage. The main study results were as follows:1. Under hydroponics condition, the agriculture index: plant height, stem diameter, length of the longest leaf, width of the widest leaf, area of the biggest leaf and node distance all increase then decrease with the increase of NH4+/NO3- ratio and reach to the best when the ratio of NH4+/NO3- is 5:5 Dry matter accumulation decrease with the increase of NH4+/NO3- ratio all along. Flue-cured tobacco's agriculture index decrease with the increase of nitrogen concentration, at other NH4+/NO3- ratios they all increase with the increase of nitrogen.2. The increase of nitrate nitrogen ratio can increase flue-cured tobacco's potassium content in leaves. When the ratio of NH4+/NO3- <7:3, the increase of ammonia nitrogen can improve the concentration of total sugar and deoxidize sugar. When the ratio of NH4+/NO3-<5:5,the improvement of nitrogen content can increase the accumulation of nitrogen, potassium, chlorine, total sugar, deoxidize sugar, dissolvable protein and starch in leaves, but decrease potassium concentration in leaves. The concentration of total sugar and deoxidize sugar both decrease with the increase of nitrogen concentration. Under the treatments of only supply ammonia nitrogen or nitrate nitrogen, the content of nicotine all increase with the increase of nitrogen content, yet nicotine concentration improve with the increase of nitrogen content at other treatments .3.Under the condition of hydroponics, content of nitrate nitrogen and activity of nitrate reductase all increase with the increase of nitrogen content and nitrate nitrogen proportion. The content of ammonia nitrogen and activity of dissociated amino acid both increase with the improvement of nitrogen concentration and ammonia proportion. The increase of nitrogen content can increase the concentration of chlorophyll and invertase activity, but decrease the activity of starch enzyme. When ratio of NH4+/NO3- excess 5:5 the content of chlorophyll and starch enzyme activity decrease to some extent When NH4+/NO3- ratios<7:3 the activity of invertase increase...