施氮量对皖南砂壤土烤烟碳氮代谢动态变化的影响

Changes of Carbon-Nitrogen Metabolism of Flue-Cured Tobacco with Sweet Aroma in South Anhui Under Different Fertilization Rates

选取皖南典型植烟土壤,对不同施氮(N)量烤烟生长发育过程中硝酸还原酶、转化酶活性和碳氮代谢产物含量的变化动态进行了测定分析。结果表明,随施N量的增加,硝酸还原酶活性提高,活性高峰下部叶出现在移栽后40天;中、上部叶出现在移栽后55天,高峰值处理N8(N8kg/667m2)>N7(N7kg/667m2)>N6(N6kg/667m2)>N5(N5kg/667m2)。在烟叶生长发育过程中转化酶活性达到最大值后明显下降。烟株地上部总N累积量、烟碱含量和烟碱累积量不断增加,施N量愈高增加幅度愈大。总糖含量随施N量的增加而减少,上部叶总糖含量的积累水平低于中部叶和下部叶,上部叶中N8处理总糖含量最低。

Typical tobacco soils in South Anhui were selected to investigate the changes of the activities of some enzymes and product contents of carbon-nitrogen metabolism during the growth of flue-cured tobacco. The results showed that the nitrate reductase activity increased first with the increase of N fertilization rate, but decreased significantly after 40 d of transplant for bottom leaves and 55 d for middle leaves and top leaves. The peak value of nitrate reduetase activity was N8 （N 8 kg/667m^2） 〉N7 （N 7 kg/667m^2） 〉N6 （N 6 kg/667m^2） 〉N5 （N 5 kg/667m^2）. The invertase activity also decreased significantly after reaching the peak value. The accumulative content of total nitrogen, the content and accumulative content of nicotine in tobacco leaves increased gradually, showed positive responses to the increase of N fertilization rate. The content of total sugar decreased with the increase of N fertilization rate, the accumulation of total sugar in top leaves was lower than those in middle and bottom leaves. N8 treatment showed the lowest content of total sugar.