Study On Optimizing Recipe Of Nutrient Solution For Floating Seedling

In order to improve the quality of tobacco seedlings under low temperature and little sunshine in Hunan province. Using the Yunyan 87 as the material, this research study on the effect of nutrient solution with different nitrogen forms and ratio?different types of phosphorus salts and concentration different concentration of microelements on the growth and physiological property of tobacco seedlings, also verify the developed nutrient solution by practice operating in tobacco and paddy of Hunan province effectively. The valuable results showed as following:1. The test results of nutrient solution with the different nitrogen forms and ratio on physiological property of tobacco seedlings showed that, the nutrient solution with 100% NO₃^--N is good for the root growth and chlorophyll synthesis. However, for the blade, stem girth, root system vitality and nitrate reductase activity of tobacco seedlings, the nutrient solution with 50% NO₃^--N+50% NH4+-N is better than that with 100% NO₃^--N. The concentration in 700mg/L or 500mg/L is better than others on agronomic traits and physiological index when breeding the tobacco seedling. The nutrient solution with 50% NO₃^--N+50% NH₄H₂PO₄ is better than another on agronomic traits, chlorophyll content, stem girth and root system vitality.2. The test results of nutrient solution with the different types of phosphorus salts and proportion of phosphorus on physiological property of tobacco seedlings showed that, NH₄H₂PO₄ is better for the syntheses of Chlorophyll a and KH₂PO₄ is better for the syntheses of Chlorophyll b. The root-shoot ratio increased with increasing of phosphorus concentration and other physicochemical index reached maximum at the time of 3:1.5:3.3.The test results of nutrient solution with increasing the concentration of Mn²⁺?Fe³⁺? Cu²⁺ on physiological property of tobacco seedlings showed that, when the concentration of Mn²⁺ or Fe³⁺ in 50-100 mg/kg, growth and every physicochemical indexes of tobacco seedlings is better than check treatment. Compared to control, the best concentration of Cu²⁺ in nutrient solution is 5 mg/kg.4. The test results of developed nutrient solution proved by practice operating in tobacco and paddy of Hunan province showed that, increasing the temperature of seedling poor can effectively stimulate tabacco seedling to nutrient absorption, increase leaf chlorophyll content and growth rate of above-ground; The plant height of the treatment using optimization nutrient solution B was up to 11.17cm and the stem thickness was up to 1.46cm, Every physicochemical indexes of the tobacco seedlings using two kinds of optimization nutrient solution were better than those of the tobacco seedlings using check nutrient solution.