Influence Of Lower Leaves Harvesting Time And Different Fertiliziler Level On Tobacco Physiological Characteristics In Maturation And Quality

We have studied the influence of different lower leave harvesting time, organic fertilization rate and level of nitrate N on the tobacco physiological characteristics in the maturation and quality. The result indicates that:1.As the harvesting time delayed, the activity of Invertase and PPO in the lower leaves increases at first then decreases, while the activity of Ascordate Oxidase increases slowly at first then increase quickly. Since the time of 5 days after topping, the activity of all these enzymes changes more differently. The content of all the chemical components changes more differently since the time of topping. Because the upper leaves rob the nutrition and the senescence of themselves, the lower leaves senesce more quickly since the time of 5 days after topping.2.To some extent, the earlier the lower leaves are harvested, the better quality the cured lower leave will have. Compared to other disposals, the cured lower leaves will have bigger leaf thickness, higher weight per unit leaf area, more orange leaves and more reasonable content of all the chemical components if they are harvested at the time of 5-10 days after topping.3.If the lower leaves are harvested normally (at the time of 15 days after topping), the activity of the Invertase in the upper leaves has two peaks; one appears at the time of 10 days after topping, another appears at the time of 40 days after topping. If the lower leaves are harvested at the time of topping or 5 days after topping, the activity of the Invertase in the upper leaves varies differently: the first peak disappears while the second peak is enhanced greatly. If the lower leaves are harvested at the time of 10 days after topping, the first peak of the activity of the Invertase in the upper leaves will not be influenced. The activity of PPO in the upper leaves increases slowly at first then decreased quickly regardless of the time that the lower leaves are harvested, but if the lower leaves areharvested at time of topping, 5 days after topping and 10 days after topping, the activity of PPO in the upper leaves is lower and will decrease earlier than those whose lower leaves are harvested at time of 15 days after topping. Whenever the lower leaves are harvested, the activity of Ascordate Oxidase in upper leaves will decrease correspondingly.4. To some extent, the earlier the lower leaves are harvested, the better quality the cured upper leave will have. Compared to other disposals, the cured upper leaves will have smaller leaf thickness, lower weight per unit leaf area, more high and middle class leaves and more reasonable content of all the chemical components if they are harvested at the time of 5-10 days after topping.5. With the rate of organic fertilization increased, the activity of the Invertase in the lower leaves is enhanced obviously. The activity of Ascordate Oxidase in lower leaves is low when the rate of organic fertilization is 300kg/hm2, however, when the rate of organic fertilization is increased to 450kg/hm2, the activity of Ascordate Oxidase in lower leaves will be enhanced greatly. When the rate of organic fertilization is 300kg/hm2, With the rate of organic fertilization increased, the lower cured leaves will have bigger leaf thickness, higher weight per unit leaf area, higher content of TS, RS, starch and K+, lower content of TN and Nicotine. In a word, when the rate of organic fertilization is 300kg/hm2, the quality of the lower cured leaves is better.6. With the rate of organic fertilization increased, the activity of the Invertase in the upper leaves is not influenced obviously. When the rate of organic fertilization is 150-300kg/hm2, there is not obvious influence on the activity of the NR in the upper leaves, but when the rate of organic fertilization is increased to 450kg/hm2, the activity of the NR in the upper leaves is enhanced greatly. When the rate of organic fertilization is 300kg/hm2, the activity of Ascordate Oxidase in upper leaves is enhanced obviously. With the rate of organic fertilization increased, the a...