Effects Of Appling Organic Acids On Flue-Cured Tobacco Nitrogen Metaboism And Leaf Quality

From 2002 to 2004 ,using hydroponics and potter plant we studied different and similar effects on flue-cured tobacco growth and nitrogen metabolism that different organic acids and amino acids may take. On the following experiments we choosed malic acid to further study the effects of it on flue-cured tobacco growth, nitrogen metabolism and leaf quality .Following are the experiment results:1 the effects on flue-cured tobacco growth and nitrogen metabolism that amino acid and organic acid have taken Adding right amount of organic acids and amino acids to the nutrient solution can cause active effects on tobacco growth-development and the accumulation of nitrogen in plant, affecting the synthesis and degradation of chloroplast and the relative content of chloroplast and carotenoid,improving the root vitality,encouraging the accumulation of plant's dry matter 。Generally organic acid improved the tobacco's growth and the accumulation of dry matter and nitrogen greater than amino acid. 2 the effects on tobacco growth and nitrogen metabolism that malic acid have taken Applying right amount of malic acid, the lamina and the plant height grew slowly in the initial phase, while once entering the busilygrowing tobacco grew quickly. The numbers of leaf length and leaf width were higher than the control. The earlier malic acid was applied, the more distinct effects were. The right amount of malic acid promoted the tobacco' growth and the accumulation of nitrogen, accelerating the release of nitrogen in soil, doing well in tobacco leaf maturing and burning up. In certain scope as the increasing of malic acid concentration the root vitality was increased, and nitrogen metabolism was strengthened in root. It can be stated that the activity' strengthening of nitrate reductase, the decreasing of content of nitrate nitrogen, the increasing of content of ammonium nitrogen; but in leaf the quantity of nitrogen' reduction decreased. The decreasing of quantity of nitrate nitrogen and nitrate reductase while the assimilation will be strengthened can state it. The increasing of the content of ammonium nitrogen and the activity of glutamic synthetase can state it. Applying malic acid varied the condition of nitrogen metabolism in the leaf and root. It increased the proportion of reduction and assimilation in the root and decreased the proportion of reduction in the leaf. Generally it encourages flue-cured tobacco's nitrogen metabolism and strengthens the accumulation of nitrogen in plant. Applying malic acid caused the variation of nitrogen metabolism condition in plant, which caused "amino acid effect" which may be the main reason that promoted the growth of root.3 the effects on flue-cured tobacco quality that malic acid have taken As the increasing of quantity of malic acid, in tobacco leaf carbohydrate has a decreasing tendency and nitrogen has an increasing tendency. 20 days after transplanted, applying malic acid encouraged nitrogen metabolism in leaf, lift the quantity of nicotine and total nitrogen in upper leaf, and decrease the quantity of total sugar, starch and reducing sugar.40 days after transplanted, applying malic acid decreased the quantity of nitrogen, nicotine and total nitrogen in upper leaf, and increased the quantity of total sugar, starch and reducing sugar. 60 days after transplanted, each chemical component that applies malic acid had little difference with the control. This showed that applying malic acid in initial phase could greatly affect the chemical components in tobacco leaf. Applying malic acid has few effects on nonvolatile organic acid in each disposition leaf, but it increased the content and proportion of polypolidy carboxylic acid. Increasing the q...