The Effects Of The Interaction Of Molybdenum And Nitrogen On Growth And The Absorption And Distribution Of Nitrogen In Flue-cured Tobacco

The experiment was carried out in scientific and educational park of Henanagricultural university during2012-2013. Flue-cured tobacco cultivars K326was usedin a pot experiment. The experiment was orthogonal test of double factors and it hadnine treatments in total. The experiment set up three nitrogen fertilizer levels:N0(without nitrogen fertilizer); N0.15(0.15g/kg soil); N0.3(0.3g/kg soil). There are threemolybdenum fertilizer levels: Mo0(without molybdenum fertilizer); Mo0.15(0.15mg/kg soil), Mo0.3(0.3mg/kg soil). The experiment mainly studied the effect ofnitrogen fertilizer level, molybdenum fertilizer level and interaction of nitrogrn andmolybdenum on the growth, the absorption and distribution of nitrogen and the mainchemical composition of flue-cured tobacco. The main research contents and resultsare as follows:1The effects of the interaction of molybdenum and nitrogen onagronomic characters of flue-cured tobaccoThe study showed that the plant height, stem circumference, effective leafnumber and maximum leaf length, leaf width and leaf area of flue-cured tobacco hadan increasing trend as the delay of growth period. The nitrogen and molybdenumfertilizer can increase the every index of agronomic characters in flue-cured tobacco.The nitrogen and molybdenum has significant synergistic effect on the agronomiccharacters of flue-cured tobacco. The nitrogen fertilizer can increase the index ofagronomic characters even without nitrogen. The agronomic characters has theoptimal performance under the appropriate level of nitrogen application rate. Themolybdenum fertilizer has a great influence on agronomic characters of flue-curedtobacco under medium level of nitrogen application rate and without nitrogen, and itcan promote the growth of flue-cured tobacco. The molybdenum fertilizer has lesseffect on the agronomic characters of flue-cured tobacco under high level of nitrogenapplication rate. The probable reason is that the application rate of nitrogen becomethe main factors that influence the growth of flue-cured tobacco under the plentyapplication rate of nitrogen. 2The effects of the interaction of molybdenum and nitrogen on drymatter accumulation of flue-cured tobaccoThe test results show that the whole plant dry matter accumulation intensity offlue-cured tobacco was higher under the medium level of nitrogen application ratefrom the vigorous growth period to mature period. The whole plant dry matteraccumulation intensity of flue-cured tobacco has a trend of increasing first anddecreaseing later. The molybdenum fertilizer can promote the whole plant dry matteraccumulation of flue-cured tobacco under medium level of nitrogen application rateand without nitrogen, and it has a better effect under high level of molybdenumapplication rate. The maximum of the whole plant dry matter accumulation reached336.54g and595.53g respectively under medium level of nitrogen application rate andwithout nitrogen. The molybdenum fertilizer has no significant effect on the wholeplant dry matter accumulation of flue-cured tobacco under high level of nitrogenapplication rate. The leaf dry matter accumulation intensity of flue-cured tobacco washigher under mediun level of nitrogen application rate. The whole plant and leaf drymatter accumulation intensity of most of the treatments are maximum at60-75daysafter transplant. The dry matter accumulation of root system of flue-cured tobacco arethe highest under mediun level of nitrogen application rate, and the maximum of itreached66.04g. The low nitrogen stress can inhibit the growth of root system offlue-cured tobacco. The root shoot ratio was higher under the level of no nitrogenapplication rate at75and90days after transplant. The nitrogen fertilizer andmolybdenum fertilizer can increase the dry matter accumulation of flue-cured tobacco,and the nitrogen and molybdenum has significant synergistic effect on the dry matteraccumulation of flue-cured tobacco. The nitrogen fertilizer has a positive effect on drymatter accumulation of flue-cured tobacco, and the dry matter accumulation offlue-cured tobacco was higher under medium level of nitrogen application rate. Thedry weight of roots, stems, leaf, the fresh weight of root, whole plant dry matteraccumulation intensity and leaf dry matter accumulation intensity of flue-curedtobacco were the highest under mediun level of nitrogen application rate. Themolybdenum fertilizer can promote dry matter accumulation of flue-cured tobaccounder the same nitrogen level. In general, medium nitrogen and high molybdenumlevel was beneficial to the dry matter accumulation of flue-cured tobacco.3The effects of the interaction of molybdenum and nitrogen onrelevant indicators of carbon and nitrogen metabolism in flue-cured tobaccoThe nitrogen and molybdenum fertilizer has a significant effect on the activity ofnitrate reductase, soluble protein and amylase in flue-cured tobacco leaves, and theyhad a significant synergistic effect. The nitrogen fertilizer has an effect on theinvertase activities, but the molybdenum fertilizer didn’t have a significant effect oninvertase activities. The carbon and nitrogen metabolism of flue-cured tobacco isrelatively balanced under the condition of medium nitrogen level. The tobacco plantswitches to carbon metabolism at the end of the vigorous growth period. Themolybdenum fertilizer can evidently promote the activity of nitrate reductase, and theactivity of nitrate reductase was higher under high molybdenum level. Themolybdenum fertilizer didn’t have an obvious effect on invertase of tobacco leaf. Themolybdenum fertilizer can enhance the amylase activity under the condition ofmedium nitrogen level and without nitrogen, and the amylase activity was higherunder medium molybdenum level. The molybdenum fertilizer didn’t have an obviouseffect on amylase activity under high nitrogen level. The time that the content oftobacco leaf soluble protein reached the maximum value was ahead of time withoutnitrogen. The molybdenum fertilizer can increase the content of soluble protein. So,appropriate application of molybdenum fertilizer under medium nitrogenous fertilizerlevel was very significance on the balance of carbon and nitrogen metabolism influe-cured tobacco. The medium nitrogen and high molybdenum level was beneficialto the carbon and nitrogen metabolism of flue-cured tobacco under this experimentalcondition.4The effects of the interaction of molybdenum and nitrogen on theabsorption and distribution of nitrogen in flue-cured tobaccoThe accumulation content of nitrogen in flue-cured tobacco has a trend ofincrease gradually as the delay of the growth period. The accumulation content of thetotal plant, root, stem and leaves in flue-cured tobacco were the highest under mediumnitrogen level, and the maximum value reached8.5,1.27,2.33and4.98g plant-1resprctively. The molybdenum fertilizer has a positive effect on the accumulationcontent of nitrogen in tobacco root under the same nitrogen level. The accumulationcontent of nitrogen in tobacco root was the highest at most of the growth period underhigh molybdenum level. The molybdenum fertilizer can promote the accumulationcontent of nitrogen in tobacco stem without nitrogen fertilizer. The molybdenumfertilizer had a different effect on the accumulation content of nitrogen in tobacco stem at different growth period under the condition of medium and high nitrogen level.The accumulation content of nitrogen in tobacco leaves was the highest in highmolybdenum level under the same nitrogen level. The molybdenum fertilizer canpromote the accumulation content of nicotine in tobacco leaves under the condition ofmedium nitrogen level and without nitrogen, and it was higher under highmolybdenum level. The molybdenum fertilizer did not play a role on the accumulationcontent of nicotine in tobacco leaves under the condition of high nitrogen level. Themolybdenum fertilizer can promote the accumulation content of nitrogen of tobaccoleaf and root to a certain extent. The tobacco plant was little small at30days aftertransplant, so the accumulation of nitrogen was higher in tobacco leaves. The rootsand stem of tobacco plant grow faster as the growth of tobacco plant, the distributionproportion of nitrogen in root and stem was increased. The medium nitrogen and highmolybdenum level was beneficial to the absorption of nitrogrn in flue-cured tobacco.5The effects of the interaction of molybdenum and nitrogen on themain chemical composition of flue-cured tobaccoThe content of reducing sugar, starch and ratio of total sugar to nicotine influe-cured tobacco decreases as the increase of nitrogen application rate. The contentof total sugar was slightly higher in the medium nitrogen level, but the content of totalsugar in flue-cured tobacco had a little difference between the medium nitrogen leveland without nitrogen. The ratio of total nitrogen to nicotine didn’t make a bigdifference between the treatments. The molybdenum fertilizer can increase the contentof total sugar and reducing sugar in flue-cured tobacco without nitrogen, and theywere highe under medium molybdenum level. The molybdenum fertilizer candecrease the content of starch without nitrogen. Under the condition of mediumnitrogen level, the molybdenum fertilizer can increase the content of total sugar influe-cured tobacco, and it was higher under medium molybdenum level. The effect ofthe content of reducing sugar was not obvious, and the molybdenum fertilizer canincrease the content of starch. Under the condition of high nitrogen level, themolybdenum fertilizer can increase the content of reducing sugar and increase thecontent of starch. The total nitrogen was the highest in the treament N0.3Mo0.15indifferent parts of flue-cured tobacco. The content of total nitrogen of the differentposition of flue-cured tobacco were2.25%,1.66%,1.51%. The molybdenum andnitrogen application had a synergistic effect on the improvement of the content oftotal nitrogen in flue-cured tobacco. The molybdenum application can promote the synthesis of nicotine in central and upper leaves and decrease the content of nicotinein lower leaves in flue-cured tobacco without nitrogen. Under the condition ofmedium level of the nitrogen fertilizer, the molybdenum fertilizer can improve thecontent of nicotine in each part of flue-cured tobacco leaf. Under the high nitrogenlevel, the molybdenum fertilizer can decrease the content of nicotine in each part ofthe flue-cured tobacco leaf.