The Technology For Reducing Nicotine And Improving Potassium Content In The Flue-cured Tobacco Leaves From The Middle And Upper Stalk Position And Its Physiological Mechanism

The pot-culture,hydro-culture and field experiments were carried out,to elucidate the effects of several technologies for reducing nicotine and improving potassium content in the flue-cured tobacco leaves and its physiological characteritics by using flue-cured tobacco K326,on the Sanming Branch of Tobacco Institution of Fujian Province and Qinliu county of Sanming city,in 2007 and 2008.The main results were shown as follow:(1) The girdling technologies conducted at different times took effects on reducing nicotine content and improving potassium content in the upper leaves,cutter leaves and lower leaves.The content of nicotine reduced by 21.91%～41.29%,15.18%～42.09%and 15.41%～39.58%,and the content of potassium increased by7.78%～47.75%in the upper leaves;cutter leaves and lower leaves,respectively.By the treatment,the activity of NR in leaves and root declined,the invertase activities in leaves and roots increased and enhance root vigor,which is beneficial to promote carbon metabolism,while inhibit nitrogen metabolism,improving the ratio of N to C content in tabacco.The most suitable girdling is conducted one the same day of decapitation, enhance the quality of tobacco leaves.(2)The roots-cutting treatment showed the obvious effects on reducing nicotine content in the middle and upper leaves,and slight effects were found in lower leaves.The treatment for 20mg/Kg IAA showed the best effects,while the treatment for 10mg/Kg and 30 mg/Kg IAA no significant effects on potassium content in the lower leaves was detected.For improving K,The treatment for 5 cm from stem gave better effects on the upper leaves,and re verse is true in middle and lower leaves for 10 cm.In general,the NR activities in tobacco leaves and roots declined,but invertase activities and root vigors increased by the treatment of roots-cutting.(3) Spraying plant growth regulators IAA,2,4-D and GA₃ treatment showed reducing nicotine and improving potassium content effects in a certain degree.The treatment for 20mg/Kg IAA showed the best effects among all the treatments,the higher and lower content of IAA declined the benificial effects.There were no signicant difference among the treatment for spraying 2,4-D in a variety concentrations,the best effects were found in the treatment by 30mg/Kg 2,4-D.and the best effects were found in the treatment by 20mg/Kg for GA3.Spraying IAA,2,4-D,GA3 with different concentrations on suitable date after tip pruning were benificial for enhanced root vigor and invertase activities in roots,for the more,reduced the NR activities in leaves and root,and the best effects were found in intraday.(4) The treatment by reagents of reducing nicotine and improving K reduced nicotine and improving potassium content in leaves by 32.74%,34.60%,23.62%for the upper,middle,and lower leaves,and increased potassium contents by 25.71%,32.04%,33.00%,respectively.For physiological response,the reagent enhanced the activities of invertase,and reduced the activities of nitrate reductase,glutamine synthetase,ODC,PMT and MPO,resulted in reducing the synthesis of nocotine.Additionally,the reagent enhanced root vigor,the activities of ATPase,the absorption capacity and quantityof K in the plants of tobacco.Push the transporrtation of K from to the leaves.It is the physiological mechanics of the reagent for reducing nicotine and improving K.(5)Field experiments showed that the reagent reduced nicotine contents in leaves by 28.93%,10.43%for B3F andC3F respectively,and the potassium content in leaves increased by 21.51%,29.58%,respectively.The components of chemical compounds in the leaves harmony with each other and met the standards of tobacco leaves,the content of total aromatic compounds was higher than all the control.Therefore,it is feasible to be popularized in practices.