Analysis On The Difference Of Flue-cured Tobacco Metabolism And Quality Between Puer And Yuxi Areas In Yunnan Province

Two representative ecological areas Yuxi and Pu-er were selected to study the relationship between carbon-nitrogen metabolism, secondary metabolism and the accumulation and distribution of materials in tobaccos under different ecological conditions. It is clear that different ecological conditions in Yuxi and Pu-er have different influences on the qualities of tobaccos and the metabolic mechanism. They have an important significance in guiding production and revealing features of tobaccos. The main results are as follows:1. Ecological factors affect nitrogen metabolism in tobaccos. The higher altitude and stronger ultraviolet rays inhibit GS, NADH - GOGAT, NAD GDH activity of the tobaccos in Yuxi, which resulted the strength of the nitrogen metabolism was less than the tobaccos in Puer. The stronger intensity of nitrogen metabolism in Yuxi promoted starch and nicotine accumulation from the fixed carbon earlier, so tobaccos in Pu-er had more starch and nicotine. The GDH and GOGAT activities were higher later after transplant in Yuxi tobaccos than Pu-er. Because the ability of the nitrogen assimilation is low at earlier stage, the nitrogen mobilization of the plants started early. It may be the inevitable requirement for the redistribution of inclusions and the quality of tobacco leaves after topping;2. Ecological factors affected carbon assimilation capacity and carbon flow distribution in tobaccos. The lower temperature and longer sunshine duration can improve SPS and SS activity. The increasing of SPS activity resulted that the sucrose accumulated more in Yuxi. As the SS activity was high, the monosacchavide and starch accumulated less. And because of the higher altitude and the stronger UV - B radiation in Yuxi, the organic acids and polyphenols accumulated more from the fixed carbon.3. Ecological factors influenced the accumulation of organic acids in tobacco leaves. The altitude of Yuxi is beneficial for the accumulation of the organic acids compounds. The altitude of Pu-er is lower than Yuxi, and the tobaccos in Yuxi accumulated less organic acids compounds. So the differences in elevation may be a decision factor for carbon flow distribution. But the differences in organic acids accumulation may be caused by the coordination degrees of the carbon and nitrogen metabolism. The ecological environment inhibit nitrogen metabolism possess in Yuxi, and the nitrogen redistribution started at an early time, at the same time the vigorous carbon metabolism increased the accumulation of organic acid. This may be the fundamental reason for the differences of organic acids.4. Ecological factors affected polyphenols metabolism and the accumulation of its materials. In Yuxi the lower temperature, the lower humidity, the higher elevations and the strong ultraviolet rays can improve the PAL activity, which increased strength of the polyphenols metabolism. And the accumulation of ultraviolet absorption materials increased ,which can reduce the harm from the ultraviolet light and enhance the resistance ability. In Pu-er, the PAL activity is lower under the lower altitudes and the high temperature, which resulted the polyphenols materials accumulated less than Yuxi.5. Ecological factors affected terpenoids and alkaloids metabolism and the accumulation of their materials. At the alkaloids metabolism, because of the vigorous nitrogen metabolism of tobaccos in Pu-er, the TDC and PPO activity are higher and nitrogenous compounds accumulated more. But in Pu-er the characteristic of nitrogen metabolism in tobaccos is still determined by its ecological conditions. At the terpenoids metabolism, the expression of DXR gene gradually reduced during development in both areas. Before 80 days after transplanting, the expression of DXR in tobaccos of Yuxi was less than Pu-er. And the content ofβ-carotenoids and luteins was more in tobaccos of Pu-er, but chlorophyll accumulated more in tobaccos of Yuxi. This might be caused by the high temperature in Puer.