不同形态氮配施对烤烟碳氮代谢及烟叶产质量的影响

以K326烤烟品种为材料,通过生育期烟株的碳氮代谢主要相关酶活性及其主要代谢产物含量动态变化,从氮素形态调控的角度对烤烟产量和烟株碳氮代谢的影响进行探讨。结果表明,不同配比硝态氮和铵态氮对烤烟品质有明显的影响。随着硝铵比的增加,烤后烟叶的可溶性总糖、还原糖含量明显增加,而烟碱、蛋白质含量明显降低,但是对全氮含量没有影响;硝态氮和铵态氮配合施用有利于烤烟产量和产值的提高。适当的硝铵比可以有效调节烟株碳氮代谢及其产物,有利于生长前期烟株维持较高的硝酸还原酶、谷氨酰胺合成酶活性和水溶性蛋白质、游离氨基酸含量,保持较高的氮代谢,降低生长前期烟株淀粉酶的活性,提高可溶性总糖和淀粉含量,而在烟叶生理成熟期能够适时提高淀粉酶活性,即促进前期碳水化合物的合成和后期碳水化合物的分解。在该试验条件下,以75%～50%硝态氮+25%～50%铵态氮的施用比例最佳。

Effects of Nitrogen Forms on Carbon and Nitrogen Metabolism and Quality of Flue-Cured Tobacco

Tobacco variety K326 was used as field experimental materials. By testing the variation trends of the relative enzyme activities and their metabolism products during tobacco growth various stages, from the perspective of nitrogen forms regulation that flue-cured tobacco pro- duction and carbon and nitrogen metabolism of tobacco plants were discussed, the results were as follows ： The ratio of NO3-N/NH4＋ -N can af- fect quality of flue-cured tobacco significantly. As the increase of NO3- -N/NH~ -N ratio, the contents of soluble sugar and reducing sugar in cured flue-cured tobacco leaves obviously increased. While the contents of protein and nicotine decreased. But the ratio of NO3 -N/NH4＋ -N had no effect on total nitrogen contents. Applying NH~-N and NO3- -N in different proportion is good at increasing yield and economical in- come. The suitable ratio of NO3 -N/NH4＋ -N can regulate the carbon and nitrogen metabolism and their products of tobacco plants. During to- bacco growth early stage, the suitable ratio of NO3-：-N/NH4 -N was good at nitrate reeducates and glutamate ammonia lipase activities, higher soluble protein and free amino acids contents. These made tobacco plants have high ability of metabolism. During tobacco growth early stage, the suitable ratio of NO3 -N/NH4＋ -N is good at amylase activity, increasing the contents of soluble sugar and starch. During the physical ripe stage the amylase activity was increased properly can enhance carbohydrate synthesis in the prophase and carbohydrates hydrolysis in the ana- phase. This experimental results showed that 75% -50%NO3--N ＋25% -50%NH4＋-N was the best application proportion.