Teruyoshi Nagao

Studies on the Growth of Tobacco Roots : XI. Effect of root-cutting and no aeration to roots on the contents of nicotine in the whole leaves

For the purpose of finding the influence of root-cutting and no aeration treatment to roots at flowering stage on the content of nicotine in the whole leaves, experiments were conducted by using several varieties of water-cultured and field-grown tobacco. The results obtained were as follows. 1. According to the data of water-culture experiment, nicotine concentration in the leaves of Hicks and MC subjected to no aeration treatment was lower than that in the root-cut tobacco. On the other hand, the whole leaves of non-topping tobacco contained lower quantity of nicotine than those of the topped tobacco subjected to no aeration and root -cutting. 2. In Hicks variety, a close relationship was observed between the respiratory rate of whole roots and concentration and content of nicotine in the whole leaves. In MC variety, the correlation between the respiratory rate of whole roots and nicotine concentration was significant. 3. According to the data of field experiment, concentration and content of nicotine in the whole leaves of high nicotine varieties from which the adventitious roots originated from stalk base had been cut off tended to increase by lower topping, and tended to decrease by higher and non-topping. In low nicotine varieties, effect of cutting adventitious roots was not so remarkable as high nicotine varieties.