Variation of Manganese, Zinc, and Copper Contents in Different Leaf Position of Flue-cured Tobacco in Heilongjiang

The changes of manganese (Mn), zinc (Zn), and copper (Cu) contents in different-position leaves of flue-cured tobacco were studied. The results indicated that Mn contents decreased, Zn and Cu contents increased with the increasing leaf positions and the delaying harvesting dates. The Zn content difference was extremely significant and the Mn and Cu content difference was not significant among different positions. The difference of Mn and Zn contents was extremely significant and Cu content difference was not significant among different leaf harvesting dates. Leaf harvesting dates were negatively correlated to Mn contents. The extremely significant positive correlations were observed between Zn and Cu, and extremely significant negative correlations were observed between Mn and Zn and between Mn and Cu.