白肋烟叶片着生部位与烟碱转化的关系研究

Relationship Between Leaf Location and Nicotine Conversion of Burley Tobacco

对4份白肋烟(Nicotiana tabacun L.cv.Burley)品系,按叶片着生部位依次取样,分析了烟碱含量,结果表明,烟碱含量因叶片在植株上的着生部位不同而差异较大,由下至上逐步升高,呈二次曲线分布。降烟碱含量因品系不同差异较大,高转化品系的降烟碱含量高于烟碱含量,随叶位的升高亦呈二次曲线升高;非转化品系的降烟碱含量则低于烟碱,随着叶片着生部位的升高降烟碱含量变化幅度较小,呈直线分布。烟碱转化率随着叶片着生部位的上升而逐步下降,呈二次曲线变化。下中部烟叶烟碱转化率较高,是导致烟碱含量低、香气平淡、品质低下的主要原因之一。烟叶生产中应在选用烟碱转化率低的品种同时,结合合理密植、改善光照条件等措施,控制烟碱转化率,提高烟叶香气品质和安全性。

The nicotine conversion of four Burley tobacco （Nicotiana tabacun L. cv. Burley） strains was analyzed based on the samples from different leaf location. Results showed that the nicotine content of leaf growing in different locations showed greatly difference. It gradually increased from low leaf to top leaf and exhibited a quadratic curve distribution. There was a great difference of nornicotine content among different strains. The nornicotine content was higher than nicotine content in high-convert strains. In the mean time, it went up in quadratic curve as the leaf location going up. However, it was lower than nicotine in non-convert strains. There was a small change of nornicotine content as the leaf location going up. It showed a beeline distribution. The rate of nicotine conversion （RNC） gradually decreased as the leaf location going up and presented quadratic curve distribution. The high RNC in middle and low leaf location was one of the main reason resulted in low nicotine content, weak fragrance and inferior quality. As a consequence, in tobacco leaf production not only low-RNC tobacco cultivars selection should be emphasized, but reasonable close planting technology and improvement of light conditions should be taken into important consideration, in order to control RNC and promote fragrance quality and safety of tobacco leaf.