肥料^(15)N对烟叶氮和烟碱含量的影响

Effects of Fertilizer ^(15)N on Tobacco Nitrogen and Alkaloids

利用15N示踪技术在黄壤烟区研究了烤烟不同部位烟叶氮和烟碱含量的变化及肥料氮在烟碱中的分配。结果表明,不施氮肥的情况下,烟株第10片以上烟叶烟碱含量达到3.54%;施氮量为97.5kghm-2时,10片以上烟叶烟碱含量达到4.13%以上。烟碱积累在整个生育期是呈不断增加的趋势,于移栽后7周内积累较少,烟碱积累主要集中在9～15周,到烟叶采收结束17周为122.55kghm-2。烟叶进入成熟期后,烟碱含量与各部位烟叶来自土壤氮素比例呈正相关,其中与上部烟叶相关系数达0.88。烟碱总氮中来自肥料氮于下部、中部和上部烟叶分别占28.31%,26.63%和25.45%;相应构成烟碱的氮素中,下、中、上部烟叶中有来自土壤氮分别为71.69%、73.37%和74.55%。追肥氮占施氮总量30%条件下,烟碱中氮来自追肥氮在下、中和上部烟叶分别占14.25%、15.30%和14.94%,追肥氮是烟叶烟碱总氮主要氮源。

Using 15N tracer technique,contents of N and nicotine and the ratios of 15N in nicotine in lower,middle and upper leaves were investigated in field experiments in yellow soil.The results showed that tobacco nicotine contents above the tenth leaf position were 3.54% in N=0 kg ha-2,and 4.13% in N=97.5 kg ha-2.Nicotine accumulation increased in total growth period.And relative low amount of nicotine was accumulated in 7 weeks after transplantation,while its accumulation mainly occurred in 9-15 weeks after transplantation.122.55 kg hm-2 nicotine was accumulated in 17 weeks after transplanting.And the ratios of 15N/total N in leaves of different positions of tobacco accumulated from the soil nitrogen presented positive correlation with nicotine amass,whose correlation coefficient in upper leaves reaching 0.88.N in nicotine from 15N accounted for 28.31% in lower leaves,26.63% in middle leaves and 25.45% in upper leaves respectively.Corresponding N in nicotine from soil were respectively 71.69% for lower leaves,73.38% for middle leaves and 74.55% for upper leaves.In the condition of top dressing N content accounting for 30% of total N applied,N in nicotine from 15N were 14.25% for lower leaves,15.30% for middle leaves and 14.94% for upper leaves respectively.N from top dressing was major source of N in nicotine.