Difference Of Phosphorus Use Reaction Among Different Flue-cured Tobacco Varieties

The experiments of floating seedling and potted planting and field condition were carred out separately in the Education Technical Center of Henan Agriculture University and in Yexian pingdingshan of Henan province during 2004-2005. The effects of phosphorus fertilization on the biological characteristics and physiological traits of different flue-cured tobacco varieties were studied in seeding stage and at the field condition, whereas the effects on the content and accumulating regulation of nutrient elements of the tobacco were analyzed at several growth stages in field condition. In addition, the effects of phosphorus fertilization on the quality, yield and economic benefit of the tobacco leaves were investigated. The difference of phosphorus use reaction among different varieties was obtained. The main results of the experiments were showed as follows:1. The Effects of Phosphorus Fertilization on the Seeding Growth and Physiological Traits of Different Flue-cured Tobacco Varieties.The main root length of each variety of tobacco seeding was increasing in a certain degree in trend of growth under the condition of phosphorus stress. The root volume of the seeding and the occurrence and growth of the first order lateral root were all inhibited obviously. Though the total dry matter content in shoots and root of the tobacco seeding without P treatment were all inhibited notably, but the ratio of root to shoot of the tobacco seeding increased in a certain extent. It showed that the shoots were inhibited more than the roots in the P stress. In addition, the condition of P stress caused the obvious decrease of chlorophyll content, root cell membrane permeability and P-efflux rate of each tobacco variety in seeding stage.The difference of the phosphorus use ability of different tobacco seeding existed obviously. The inhibition of P stress to K326 was small. Compared to other varieties, K326 was able to endure the phosphorus stress. The adaptation tolerances of other four varieties, Zhongyan101, Zhongyan100, NC89 and Qingsheng No.2 were poor. Therefore, it is necessary to supply more phosphorus in order to meet the demands of growth and stockiness.2. The Effects of Phosphorus Fertilization on Biological Characteristics and Disease-resistance of Different Flue-cured Tobacco Varieties.Proper phosphorus fertilization would increase the height of the plant and the stem perimeter of four flue-cured tobacco varieties, Zhongyan101, Zhongyan100, K326, and NC89. The LAI of all the varieties with P treatment after transplant 30 days were higher than that of the tobacco without P treatment. P stress leaded to the increase of the main...