| Plant growth regulators being significant tools in controlling the quality of leaves of tobacco, researches on the influence of GA,. IBA, 6-BA on the quality of top leaves of tobacco are made to enhance the quality of top leaves of tobacco in Xiannan district. This study applies 50 ppm GA, 20 ppm IBA, 100 ppm 6-BA to timely foliar spraying or root pouring of pot-planted flue-cured tobacco K346, and then observes the structure of the tissue and cell in ripe top leaves and quantifies the length of and chemical ingredients in leaves. To learn the influence of plant growth regulators on the growth of and the nitrogen metabolism in tobacco, the study also employs the nutrient solution containing 25, 50, 75 ppm GA respectively or,0.1, 1, 3, 5, 10 ppm IBA respectively to cultivating seedlings of flue-cured tobacco G80 till their developing the seventh mature leaves, and then quantifies the nitrate reductase activity, the peroxidase activity, protein in the roots and the leaves. The results are as follows.1 The influence of GA, IBA, and 6-BA on the quality of top leaves of tobacco1.1 GA, IBA, and 6-BA all lengthen leaves, and being the most potent GA can lengthen leaves by 13.7%, and they all increase the volume of cells in palisade tissue and make tonoplasts developed in sponge tissue. GA makes starch grains in sponge cells nearly all being complexes, and makes lipid droplets few. In treatment with IBA starch complexes and lipid droplets are rare, whileas in treatment with 6-BA starch complexes are extinctive and lipid droplets numerous. 1.2 GA, IBA, and 6-BA increase K in tobacco leaves, with GA being themost potent and increasing it by 34.8%.1.3 GA decreases in tobacco leaves nicotine, the ratio of nicotine to nitrogen, the ratio of nicotine to soluble sugar by 67%, 58.4%, 86.2% respectively, whileas IBA and 6-BA Increase them by 26.8%, 26.9%, 52.1% respectively. GA can decrease total nitrogen by 21.8%, whileas IBA and 6-BA increases or decreases it according to the strategy of application.1.4 GA can increase soluble sugar and starch in tobacco leaves respectively by 157.3% and 182.2%, whileas IBA decreases them respectively by 16% and 10.8%. 6-BA reduce starch by 17.5%, and increases or decrease soluble sugar in different stf ategy of application.Conclusively, GA increases in top leaves cellular volume, K, soluble sugar, decreases nicotine, total nitrogen, the ratio of nicotine to nitrogen, the ratio t>f nicotine to soluble sugar, so GA can fairly generally improve the quality of top leaves of tobacco. GA functions to significantly alter above items and its effects build up in the order of root pouring, foliar spraying, and the combination of them, and it is more capable of effection on the length, the total nitrogen, and the ratio of nicotine to nitrogen with the addition of application. Nevertheless, IBA and 6-BA in top tobacco leaves increase nicotine, the ratio of nicotine to nitrogen, the ratio of nicotine to the soluble sugar though they also increase the cellular volume and length and K, and their effection is somewhat weak and their effects don not regularly function among root pouring, foliar spraying, and the combination of them . Therefore IBA artd 6-BA cannot desirably improve the quality of top leaves.2 The influence of GA, IBA, and 6-BA on the nitrate reductase activity and the peroxidase activity and the protein content2.1 IBA decreases both the nitrate reductase activity and nitrate in roots and leaves, and promotes the dephosphorylation of the nitrate reductase and the sucrose content. GA decreases the nitrate reductase activity but increases the nitrate content in roots, and promotes the dephosphorylation of the enzyme; GA enhances the nitrate reductase activity, but decreases, the nitrate content in leaves, reduces the dephosphorylation of" the enzyme and the sucrose content.2.2 IBA and GA respectively increases or decreases the peroxidase activity in roots.'2.3 IBA increases protein in roots and leaves. GA decrease protein in roots but increase... |
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