Effects of Temperature and Nitrogen Form Interaction at Root Area on Accumulation of Biomass and Nicotine in Flue-cured Tobacco

In order to reveal the effects of rhizosphere temperature on the nicotine accumulation in flue-cured tobacco, the interaction effects of rhizosphere temperature(10, 18, 26, 35℃) and nitrogen form(100% NH₄⁺-N, 50% NH₄⁺-N+50% NO₃^--N, 100% NO₃^--N) on the accumulation of biomass and nicotine in flue-cured tobacco were studied with a pot experiment. The results showed that the biomass in tobacco plants was increased by rising rhizosphere temperature properly; NO₃^--N was more beneficial to plant growth than NH₄⁺-N. At the rhizosphere temperature of 35℃, 100% NH₄⁺-N and 50% NH₄⁺-N+50% NO₃^--N, the growth of tobacco plants was restrained, while the plants fertilized by 100% NO₃^--N grew vigorously. Nitrogen form affected the biomass content in tobacco plants more significantly than did rhizospheretemperature. The nicotine accumulation in tobacco plant peaked at the rhizosphere temperature of 18℃. The nicotine content in plants fertilized by 100% NO₃^--N was 1.64 times that by 100%NH₄⁺-N, which indicated that NO₃^--N application promoted the synthesis of nicotine. At the rhizosphere temperature of 35℃, the synthesis of nicotine was restrained. Rhizosphere temperature affected nicotine accumulation more significantly than did nitrogen form.