Yang HongQi

Fertility characteristics of differently textured soil in Wuping tobacco-growing areas.

The soil texture, Soil pH and main nutrient of 205 soil samples from Wuping tobacco-areas as well as correlation between main fertility factors in differently textured soil were researched. The results indicated that sand soil, loam soil and clay respectively account for 37.07%, 58.05%, 4.88%. The differences of main nutrient in different soil texture, while total K′being significant, were highly. And the clay’s content of main nutrient was highest, while sand soil was lowest, in the three type textured soil. The content of total P′was showed loam soil was highest and sand soil was lowest. The sand soil’s pH was higher than the clay and loam soil, the clay’s pH was the lowest. Sand: pH value has a very significant negative correlation with organic content, the content of total N and available K, and shows a significant negative correlation with nitrogen; total N shows highly significant positive correlation with nitrogen, and it significantly correlates with available K; nitrogen positively correlates with total P and available K, and highly significantly positively correlates with available P; total P and available P, total K and available K show a highly significant positive correlation. Loam soil: pH shows significant positive correlation with total P and total K; organic matter shows highly significant positive correlation with total N and total P, which are the same with total P and available K; total P significantly positively correlates with available K. Clay: pH significantly negatively correlates with total N; It has great influence in the interrelationship of fertility factors in sand soil, while less in loam soil and clay.

Effect of UV-B on growth and development and secondary metabolism of flue-cured tobacco.

By the cointegration method,the influence of sugar futures price in Zhengzhou commodity exchange on the Nanning sugar stock price was investigated based on the data from April 24,2007 to December 29,2008.The result shows that there is co-integration relation between the Nanning sugar stock price and the sugar futures price;the sugar futures price is Granger causes of the Nanning sugar stock price,but the Nanning sugar stock price is not Granger causes of sugar futures price;and in the short term,the Nanning sugar stock price and the sugar futures price are mainly influenced by themselves.Conclusions: 1)sugar futures market has hedging and price discovery role;2)the two functions of sugar futures market,hedging and price discovery,are interacted with characteristics of time delay.The suggestion is that China should speed up the development and improvement of the white sugar futures market building.

Effects of N,P,K,Mg Deficiency on Plant Growth and Leaf Glandular Trichome Development of Flue-cured Tobacco

Using flue-cured tobacco cv.K326 as material,the plant growth and leaf glandular trichomes development of flue-cured tobacco in the deficiency of nutrient elements during plant growing were studied.The results indicated that a deficiency of N,P,K,Mg not only negatively affected the growth of tobacco plant,but also had a significant effect on the growth and development of leaf glandular trichomes.N deficiency would decrease leaf area and stimulate the growth of various glandular trichomes,and the density of glandular trichome increased accordingly,while P,K,Mg deficiency would reduce the density of glandular trichome greatly besides leaf area reduction.Therefore,sufficient P,K,Mg nutrients application in the early growth stage of tobacco plant is particularly important for enhancing glandular trichome density and glandular secretion of tobacco leaves.