Correlation Analysis Between Nicotine Content and Medium and Trace Element Contents in Flue-cured Tobacco Leaves from Different Stalk Positions

The relationships between nicotine content and the contents of medium and trace elements in flue-cured tobacco leaves from different stalk positions were analyzed with descriptive statistics analysis, stepwise regression analysis and path analysis. The tobacco was cultivated with the same cultural practices at twelve counties in seven main tobacco-growing provinces. The results indicated that the contents of medium and trace element and nicotine content in flue-cured tobacco leaves from different stalk positions were of medium degree of variation. The variation of Mn content among different areas was the largest in all the tested medium and trace elements,while that of P content was the smallest. Among leaves from different stalk positions,the variation of nicotine content in lower leaves was relatively larger. The elements in the order of direct effect influencing nicotine content in lower leaves were Si> Cu> Ca> Zn> B,in middle and upper leaves were P> Fe> Cu> Mo> B and Si> Fe> Ca> Cu> B,respectively. Because of the interactions among medium and trace elements,their combined influences on nicotine content in leaves from different positions presented many variations. To reduce nicotine content in tobacco leaves by regulating the contents of medium and trace element,proper measures should be taken to leaves from each position: focusing on increasing the contents of Si,Ca and Cu for upper leaves;decreasing B and Fe contents and raising Mo content for middle leaves;reducing B content and increasing Zn and Cu contents for lower leaves.