Influence of climatic conditions on contents of main chemical components in flue-cured tobacco leaf
For investigating the influence of climatic conditions on the contents of main chemical components in flue-cured tobacco leaves, experiments on different transplanting time were carried out in Xiangcheng County of Henan Province. The climatic factors (average temperature, precipitation, sunshine hours) at different growth stages and the contents of chemical components in cured tobacco leaves (C3F and B2F) were compared, and their correlations were analyzed. The results showed that: with the delay of transplanting time, the average temperatures at fast-growing stage and field growth stage rose, while the average temperature at mature stage, the sunshine hours at fast-growing stage, mature stage and field growth stage decreased. Advanced or delayed transplant decreased the nicotine content in flue-cured tobacco leaves to a certain degree, while its effects on the other components differed between middle and upper leaves. Comparing with middle leaves, upper leaves displayed stronger correlation with climatic factors. Fast-growing stage might be the key period when climatic factors affected chemical component contents in flue-cured leaves. There was negative correlation between total nitrogen content in upper leaves and the sunshine hours at fast-growing stage, mature stage and field growth stage. The contents of reduced sugar, total sugar and starch in upper leaves positively correlated to the sunshine hours at fast growing stage, while negatively correlated to the precipitation at fast-growing stage.