The Impact Of Light, Nitrogen And Topping On The Growth And Material Composition Of Flue-cured Tobacco

In this study, through the use of sand culture and watered nutrient fluid, took flue-cured tobacco variety K326as material.Reaseached flue-cured tobacco grown under different light intensity, different levels of nitrogen supply and removal of the terminal bud conditions, results are as follows:Light intensity has an important effect on the growth of various parts of the flue-cured tobacco, With the increase of light intensity, flue-cured tobacco leaf length, leaf width, stem girth, plant height, leaf area and the various parts of the dry weight gradually increased; With the extension of the growth process, light play an more important role in promoting, CK’s stem and root dry weight have always been gradually increased,15%and42%’s stem and root dry weight increase but slow and stagnant. The light intensity can affect the synthesis of chlorophyll metabolism, with the extension of the growth process, under various treatment conditions of Chla, Chlb and Chl content were15%<42%<CK. Nitrate reductase activity was positively correlated with the light intensity,18days, CK’s NR activity was2.25μg/(g*h), was1.95times that of42%, was5.08times that of15%. With the extension of the growth process, the root activity of each treatment showed an increasing trend, but the low light intensity increased the least.Low-light conditions can cause membrane lipid peroxidation, with the extension of the growth process,42%’s content of MDA was slight higher than CK,15%’s MDA content was significantly higher than that of CK and42%; In all treated samples, No nicotine content was measured.Increasing Nitrogen concentration can promote flue-cured tobacco leaf length, leaf width, stem girth, plant height, leaf area and dry matter accumulation, conducive to the growth of aboveground parts, reduce the root-shoot ratio; a certain degree of nitrogen deficiency can promote the growth of roots and stems; Excessive of nitrogen levels can inhibit root growth; under the level of of nitrogen deficiency, the content of Chla, Chlb and Chl decreased, An adequate supply of nitrogen can increase the content of of Chla, Chlb and Chl; NR activity and root activity upward with the increase of the concentration of nitrogen, make up for the root growth weakened under high nitrogen; Nitrogen supply levels coordinated with the membrane lipid oxidation, Severe nitrogen deficiency cause the massive accumulation of MDA content, High nitrogen supply can reduce the the level of of membrane lipid oxidation; nitrogen did not result in the accumulation of nicotine.A period after the removal of the terminal bud, can promote the growth and development of the leaves, increasing the leaf length, leaf width and leaf area; slowing the growth of the plant height and stem girth; promoting root growth. However, with axillary buds growth and development, the promoting role for the growth of flue-cured tobacco brought by the removal of terminal bud gradually subsided. After removal of the terminal bud can promote the accumulation of dry matter in the root, up to33.8%; But with the growth extend, Allocation gradually reduced converted to the growth of leaves. a period of time after removal of the terminal bud chlorophyll content, NR activity and root activity increased. Remove the terminal bud promote root growth and nicotine has been rapid accumulation, nicotine can be detected in the first three days after topping, up to0.09mg/g, the accumulation of nicotine continues in the5Days, but nicotine was not measured in CK, it showed that the removal of the terminal bud induced the synthesis and accumulation of nicotine. After removal of the terminal bud, reduce light intensity, can reduce tobacco nicotine accumulation of all parts; After removal of the terminal bud, N deficiency culture conditions, leaf nicotine content is the lowest in each treatment,potassium culture conditions, the content of roots nicotine is the minimum; Night temperature has important implications to the transport of nicotine to the aerial part, CK’s nicotine content in the roots is the lowest in the process, but the nicotine content in the leaves is generally higher than other treatments.