The effect of hydro-thermal coupling on the content of nicotine in tobacco leaves

The influence of soil hydro-thermal levels on the content of nicotine in tobacco leaves was studied under the simulated indoor experiment.The results are as follows.Different soil moisture contents have different influences on the nicotine content in tobacco leaves.Under the temperatures tested,the content of nicotine in tobacco leaves increases with the increase of soil water in the range of 14%-18% during different growth stages after seedling transplant;The content of nicotine,however,decreases with the increase of soil water in the range of 20%-25%;Soil submersion has negative effect on the synthesis and accumulation of nicotine content in tobacco leaves.Soil temperature has greater impact than soil water.In the range of 15-30 ℃,the increase of soil temperature is favorable to the synthesis and accumulation of tobacco content.Hydro-thermal coupling has positive interactive effect on the synthesis and accumulation of nicotine content in tobacco leaves.The coupling is advantageous to the accumulation of nicotine content when the hydro-thermal conditions are favorable,whereas under unfavorable hydro-thermal conditions,the coupling can also increase the nicotine content through complementary interaction.