The Technical Research Of Controlling Clipping Leaves With Spraying Abscisic Acid And Paclobatrazol At Seedling Period Of Flue-cured Tobacco Sand Floating System

At present, tobacco breeding is using floating nursery where is breeding in the greenhouse, it has great air temperature and humidity, seedlings grow too fast, we must through the leaf-cutting operation to control the growth vigor of tobacco seedlings, and this measure also can improve the survival rate of tobacco seedlings transplanting. However, cut leaves subjoin the farming operations of the tobacco breeding, also increasing the probability of the spread of viral diseases. Therefore, controlling the growth of tobacco seedlings in the breeding is very important. This research take K326as the material, by foliar spraying of plant growth inhibitor ABA and PP333, screening study on the most significant physiological and biochemical indexes of tobacco growth conditions, follow-up survey research from tobacco seedlings to ota of growth status and determined the pharmaceutical optimal concentration, the finding shows that::(1) On the basis of pre-trial, it can be seen that the60mg/L ABA+60mg/LPP333composite pharmaceutical concentration is relatively ideal to control tobacco seedlings growth, so we take60mg/L to foliar spraying, using principal component analysis method to analyze test results of the tobacco physiological and biochemical indicators, obtained the most significant physiological and biochemical indicators on growth of tobacco:Pro, SOD, POD, GS, total chlorophyll, carotenoids, the removal indicators are MDA and content of soluble sugar.(2) The follow-up survey research of tobacco seedling to Ota of growth status at results show that:agronomic traits showed that the spraying of pesticides on tobacco seedling growing significantly inhibited; the ABA content, enzyme activity of SOD and GS show the minimum value before and after the transplanting period; the IAA, Pro, chlorophyll content and POD activity in the transplant before and after maximum; Maximum content of GA appears in about30days after the germination, and content of the carotenoid continued decreased.20days after transplanting, a series of indicators suggest that the growth conditions of the tobacco plant has been restored to a level similar to normal tobacco plants, on the whole, it reached the purpose of controlling the tobacco seedling excessive growth and reducing the number of clipplin leaves. (3) Using the Analytic Hierarchy Process (AHP) to comprehensive analysis and evaluate agronomic traits, the content of endogenous hormone and physiological and biochemical indicators, screening the best concentration of the pharmaceutical is60mg/L ABA+60mg/LPP333. Greater impact indicators as follows:stem circum, plant height, content of ABA, the sum weight of the these three indicators are55.54%; followed by dry weight, of the PRO, IAA, GA and POD, the sum weight of the these five indicators are29.15%; the two parts include eight indicators, the sum of the weights are84.69%.