打顶时期对烤烟根系活力及烟碱积累规律的影响

对不同打顶时期烤烟根系活力及烟碱积累规律进行了研究。结果表明,根系活力和根系烟碱含量呈显著的正相关关系。根系活力和根系烟碱含量均随打顶时期的推迟增加幅度降低,且增至最高值后下降较快。打顶时期与烤烟中上部叶烟碱含量有显著的负相关关系。中部叶烟碱含量以扣心打顶处理最高,烟碱积累强度高峰均出现在打顶后20d前后。上部叶烟碱积累强度高峰均出现在移栽后80d,且随打顶时期推迟烟碱积累强度高峰依次下降,烟碱含量也依次降低,每推迟一天打顶烟碱含量就下降0.0504%。

Effect of different topping time on activity of root system and accumulation of nicotine in tobacco plants

The experiment was conducted to study the activity of root system and the regulation of nicotine accumulation at different topping time on cinnamon soil in Xuchang,Henan Province in 2005.The activity of root system was significantly positively related to nicotine level.As the topping time delayed,the activity of root system and nicotine level increased slowly and declined rapidly from the peak value.The topping time was significantly negatively related to nicotine level in middle and upper leaves.The highest nicotine level in middle leaves appeared with topping on early button period and the highest rate of nicotine accumulation occurred about 20 days after topping.The highest rate of nicotine accumulation in upper leaves occurred 80 days after transplanting,and declined gradually with topping stage delayed.Nicotine level also declined gradually,0.0504 percent with delaying one day.