| Molybdenum is one of the essential trace elements for plants, the yield and quality of flue-cured tobacco can be improved by applying molybdenum. The molybdenum shortage in soil of the main tobacco growing area is very serious and widespread. The plant used for this study was flue-cured Yuyan 6. Soil pot experiment(set molybdenum treatment of 0, 0.2, 0.4 mg/kg in soil) and field experiment(spraying different amount of molybdenum fertilizer at rosette and fast-growing stage) were conducted to investigate the effect of molybdenum nutrition on nicotine metabolism and the quality of flue-cured tobacco. The main results are as follows:1. Mo application significantly increased the biomass in the seventieth and eightieth day after transplanting, and increased the accumulation of dry matter in the eightieth day after transplanting. The chlorophyll a, chlorophyll b content and the net photosynthetic rate could be significantly increased in the eightieth day after transplanting by the Mo application.2. The nicotine in three parts of the leaves were increased rapidly after topping, and the nicotine content in the upper leaves were increased the most; Mo application significantly decreased nicotine in upper leaf at topping stage, but had little effect on middle and low leaf. Topping decreased the Mo content in low leaf, while promoted Mo content in middle leaf; Mo application significantly promoted molybdenum content, and Mo content in the 0.4 mg Mo/kg treatment was the highest. ADC, ODC and PMT activity increased significantly after topping, Mo application can significantly reduce the activity of these enzymes, 0.4 mg Mo/kg treatment showed the most obvious reduction.3. The NR, GBSSI, GS1-3 and GS1-5 gene were expressed more strongly by Mo application from sixtieth to eightieth days after transplanting. The VIN gene was expressed strongly at the sixtieth, seventieth and eightieth days after transplanting, and the higher were the application of molybdenum, the more strongly VIN gene expressed. SPS and SPP gene were expressed more strongly in the treatment of CK at the fiftieth days after transplanting, while Mo application treatment were expressed more strongly at the sixtieth and seventieth days after transplanting. For the gene expression of SBE, there was no obvious regularity in the effect of Mo application. In general, the genes of carbon and nitrogen metabolism enzymes were expressed more strongly by the Mo application.4. The foliar application of Mo fertilizer increased the maximum leaf length and width at the seventy-fifth days after transplanting, and the 0.4mg Mo/kg treatment had the most obvious increase, but Mo had no effect on plant height, stem circumference and leaf number. The application of Mo fertilizer significantly increased the yield and production value of flue-cured tobacco, the proportion of superior tobacco leaves was significantly increased, and the economic characters of T2(spraying 50 ml molybdenum fertilizer each plant at rosette and fast-growing stage) treatment were the best. Mo application significantly reduced the nicotine in upper leaf, increasing potassium in upper and middle leaves, and the contents of total sugar and reducing sugar were raised in all parts of leaves. The Mo treatment was significantly stronger than that of non Mo treatment in color, oil and other appearance quality. Most of the aroma components increased significantly, and the neophytadiene had the most obvious increase. On the sensory evaluation, the aroma quality and aroma quantity of Mo treatment were significantly increased, and the T2 treatment obtained the highest score. Mo application can improve the delicate characteristics of the smoke quality, but can not change the style characteristics of flue-cured tobacco. |
PDF Full Text Request