Effects Of Continuous Cropping To Packing Fluecured Tobacco Chemical Composition And Physiological Characteristic

Tobacco was planted by monopoly planning, primarily. Succession crop area of tobacco was increased year by year because of finiteness arable land, economic interest and cultivation condition, which intensified the succession cropping barrier.Mu danjiang was main production base of flue-cured tobacco filled in our country. In order to ensure the product and quality of flue-cured tobacco in this area, the present study took Longjiang 911 flue-cured tobacco as material and tobacco normal rotation in Heilongjiang (wheat-soybean-tobacco) as control.Anatomy, chemical composition, nitrogen metabolism, photosynthesis and chlorophyll fluorescence changes of different succession cropping tobacco leaf were study to clear the mechanism of continuous cropping of tobacco.The chemical composition contain total nicotine, reducing sugar, total reducing sugar, crude protein, the content of N, P, K, Cl, and protein/nitrogen. The study could help to establish a reasonable tobacco farming systems, and provide basic data and technical support for maintain the quality of tobacco basic stability.The results were as follows:1.In growth process of the flue-cured tobacco, the succession cropping have significant influence to the flue-cured tobacco, reduced the flue-cured tobacco blade length, the width and the adult plant altitude obviously. Compare the different blade position, succession cropping influence the upside and middle blade mostly. An increase of the dry weight/fresh weight ratio has been considered help to improve the quality of flue-cured tobacco.The study showed that longer time succession cropping decreased the quality of downside tobacco leaf.2.In different succession cropping treatments, the starch content of tobacco leaf was related to the location of tobacco leaf. The starch content of flue-cured tobacco displays in turns was CK, the stubble of wheat,1 year of succession cropping,5 years of succession cropping. The influence of upside blade to the stubble of wheat and 1 year of succession cropping were greater than CK and 5 years of succession cropping. The influence of succession cropping to the starch content was mainly on early leaf growth, while little effect on mature tobacco leaves.Different succession cropping in prophase growing tobacco plants, free amino acids in upside and middle blade displays in turns was 5 years of succession cropping,1 year of succession cropping, the stubble of wheat, CK. The results showed that protein synthesis of CK was greater than others, which was to the benefit of tobacco leaves growth.Succession cropping increased MDA,5 years of succession cropping and 1 year of succession cropping were greater than CK and the stubble of wheat.Nitrogen and Chloride accumulation of 3 years of succession cropping and 6 year of succession cropping were greater than CK's, but it was relatively small influence to downside blade. Succession cropping increased the content of phosphorus in flue-cured tobacco,and there was less impact with the increase of leaf blades. Nearly no impact on potassium content of succession cropping flue-cured tobacco.Succession cropping had no obviously impact on ratio of protein and nitrogen content and ratio of two sugars.3 years of succession cropping and 6 year of succession cropping were greater than CK on the ratio of nitrogen and nicotine and the ratio of reducing sugar and nicotine.3.There is no significant difference in content of chlorophyll in the lower leaves between different treatments. The content of chlorophyll in upper and middle leaves was from CK, to 1 year of succession cropping, to stubble of wheat, to 5 years of succession cropping. The content of chlorophyll decreased more quickly in leaves with CK, and the flue-cured tobacco trend prolonged greening and mature later. In the mature process, the lower leaves of CK reduced quickly.4. The blade NRA of flue-cured tobacco displays in turns was CK, the stubble of wheat, 1 year of succession cropping,5 years of succession cropping, its same to the change of the content of chlorophyll, which showed that the succession cropping reduced the flue-cured tobacco blade's nitrogen metabolism obviously.5.The flue-cured tobacco blade PN-PAR response curve and the CO2 response curve were determined in different succession cropping treatment. The result showed that the 5 years of succession cropping reduced the flue-cured tobacco blade quantum yield and effect of carboxylation obviously. The maximum photosynthesis speed (A350) and the photosynthesis electron transfer speed (Jmax) was the lowest, the study explained that succession croppings years caused flue-cured tobacco photosynthesis ability being weaken directly6.In different succession cropping treatments, the actual photochemistry efficiency (φpsⅡ)of CK is higher than the 5 years of succession cropping and the 1 year of succession cropping. Flue-cured tobacco blade's apparent photosynthesis electron transfer speed ETR have the same trends toφpsⅡSimilar.5 years of succession cropping blade Fo was lower than other treatment obviously, succession cropping reduced the flue-cured tobacco blade energy of light absorption and transformation ability obviously. Flue-cured tobacco blade's maximum photochemistry efficiency (Fv/Fm) was relative stabilization, while it decreased obviously under succession cropping condition, combined with the change of Jmax, succession cropping reduced the blade's ability that absorption energy of light transform to electron obviously, and reduced the flue-cured tobacco blade's output seriously.7.In the fast growing period (the eleventh of July), the thickness of blade, palisade tissue and spongy tissue of CK and stubble of wheat were greater than 1 year of succession cropping's and 4 year of succession cropping's, and there was more influence on downside and middle blade. In the maturity phase, the thickness of blade, palisade tissue and spongy tissue of upside and middle blade was reduced gradually, but the upside leaves were thickened. Palisade tissue cell width of 4 year of succession cropping was greater than CK, and it showed that cell array of succession cropping tobacco blade was more porous.The blade ratio of 4 year of succession cropping was decreased in evidence compare with CK, and not used for photosynthesis.The results were uniform with photosynthesis data analysis.The above results showed that the flue-cured tobacco growth quantity and the leaf blade content accumulation were decreased under the succession cropping condition. On the one hand, it is because the succession cropping reduced the content of flue-cured tobacco blade chlorophyll, the photosynthesis speed and the NRA, resulting in the lower photosynthesis speed, the physical production, and the ability of used the soil nitrogen simultaneously. On the other hand, succession cropping reduced the flue-cured tobacco blade energy of light absorption and transformation ability obviously, and the assimilatory power of carbon assimilation was reduced.