中国烟草学报

本文提出了用碳氮比（C／N）和硝酸还原酶与转化酶的活性比（NR／IV）作为衡量烟叶碳氮代谢协调性和香吃味品质优劣的指标。相关分析表明，烟叶在不同生长发育时期的C／N、NR／IV活性比值、淀粉酶、转化酶、NR活性、蛋白质、烟碱、还原糖、总氨基酸含量与烟叶最终评吸总分存在不同程度的二次曲线相关关系，以C／N和NR／IV活性比值与评吸总分的相关性较大。因此，C／N比值及其动态变化模式可以作为衡量和判断烟叶香吃味品质的理想指标，NR／IV比值可作为重要的参考指标。保持适宜的C／N和NR／IV活性比值，促进碳氮代谢协调发展是获得优良香吃味品质的重要条件。通过对回归方程求最大值，得到在烟苗移栽后43天，73天，90天和烘烤叶的最佳C／N值分别为10．59，11．51，15．22，18．86和17.11，其理想的变化模式为：移栽后60天以前，碳氮比增长缓慢，60天以后，进入快速增长期。

In this paper, we proposed using the C/N and NR/IV as the index to evaluate thecoordination of C and N metabolism and the flavor quality. Correlation analysis showedthat the quadratic curve correlation existed among total sensory smoking score and theactivity of NR, amylase, invertase, NR/IV, C/N, the content of protein, nicotine,reducing sugar, total amino acid. Among them, the C/N and NR/IV have the highestcorrelation with sensory smoking score. Therefore, maintaining the suitab1e C and Nmetaholism level and reasonable dynamic changing model was essential to obtain thehighest leaf quality. lt was obtained that at 43, 60, 73, 90 days after transplanting(DATP), the best C/N value were 10. 59, 11. 51, 15. 22 and 18. 85, respectively. Before 60 DATP, the increasing rate of C/N should be slow, after 60 DATP, entering therapid growth period. The optimum C/N in cured leaf for obtaining the highest score was17. 11