Difference Of Burley Tobacco Growth And Quality Characters Among Different Altitudes In Enshi

Taking E’yan 1 as the material,the research was set up with three altitudes which were the altitude of 1560 m,1200 m and 800 m respectively in Enshi,Hubei in 2013.The effects of altitude on tobacco botanical characters,leaf photosynthetic characteristics,plastid pigment metabolism and submicroscopic structure of tobacco leaves were researched and the physical characteristics,general chemical components,neutral aroma components and sensory qualities of burley tobacco in different altitude areas were compared.The main results were as follows:1.The effects of altitude on botanical characters of burley tobacco were researched.The results showed that with altitude increasing,the plant height,the maximum leaf length and width and the effective number of leaves showed a declining trend before 45 days after transplanting.The plants in low altitude areas grew fast in the early growth stage.After 60 days after transplanting,the plant in middle altitude areas had an obvious growth advantages.The plant height,stem girth,the effective leaves number and leaf area index of burley tobacco were higher in middle altitude areas than in other ones and the difference between middle altitude areas and high altitude areas was significant at 0.05 probability levels.2.The effects of altitude on photosynthetic characteristics of tobacco leaves were researched.The results showed that at 40 days after transplanting,the net photosynthetic rate and stomatal conductance of tobacco leaves were significantly higher in middle altitude areas than in other ones and the difference of the intercellular CO₂ concentration and transpiration rates of tobacco leaves between middle and high altitudes areas was not significant,but significantly higher than those indicators of tobacco leaves in low altitude areas,respectively.At 60 days after transplanting,the stomatal conductance of tobacco leaves in high altitude areas was highest among three altitude areas.There was no significant difference on the net photosynthetic rate of tobacco leaves in different altitude areas,while significantly difference on the intercellular CO₂ concentration of tobacco leaves in different altitude areas at this growth stage.At 80 days after transplanting,the net photosynthetic rate,transpiration rate and stomatal conductance of tobacco leaves were the higher in low altitude areas than in other altitude areas,but it was no significant difference among different altitude areas.Whereas,the intercellular CO₂ concentration of tobacco leaves in middle altitude areas was the highest.3.The difference of plastid pigment contents and related genes expression of burley tobacco among different altitudes in Enshi was investigated at the fast grow stage and the mature stage.The results showed that the contents of chlorophyll a,chlorophyll b and total chlorophyll in burley tobacco leaves in middle altitude areas were highest,and the content of total carotenoids at the fast grow stage among different altitude had the same trend.The difference between middle altitude and other altitudes was significant or very significant.The higher total carotenoids contents of burley tobacco leaves were achieved at the mature stage in high altitude areas and it increased significantly relative to at the fast grow stage.In middle altitude planting areas,the expression of chlorophyll synthesis genes at two growth stages and carotenoid synthesis genes at the fast grow stage were efficient,while the efficient expression of the genes related carotenoid synthesis at the mature stage appeared in high altitude planting areas.Middle altitude was more suitable for planting E’ yan 1.4.The structure of chloroplasts and cell wall and the number of starch grains and osmiophilic material of burley tobacco leaves were researched by observing the leaves submicroscopic structures at different growth stages in three altitude areas.The results showed that the cell organelle distribution of burley tobacco leaves was similar at different growth stages in different altitude areas which showed relatively little cytoplasm,large central vacuoles and chloroplasts close to cell wall,and nucleus near the end of cells.The compactness of tobacco leaf cells was slightly different in different altitude areas.There were a minimum amount of high electron density osmiophilic materials in large central vacuole of palisade cells.The volumes of palisade tissue and starch granules of chloroplasts in leaf cells increased with the elongation of growth period.Altitude affected the cell wall thickness and the number of starch and osmiophilic granules of leaf cells.As the altitude increasing,the cell wall became thick and the number of starch and osmiophilic granules decreased gradually.The content of thylakoid layer of leaf cells was the highest in low altitude areas,followed by high altitude areas and it was the lowest in middle altitude areas.5.The influences of altitude on the physical properties of air-cured burley tobacco were analyzed.The results showed that the burley tobacco leaves in middle altitude areas had the minimum rate of stalk within suitable range.The difference of the filling value of burley tobacco leaves was significant among three altitude areas.The length and width of lower leaves were significantly longer in middle altitude areas than in other ones.The length and width of middle leaves had no significant difference in low and middle altitude areas,but they were significantly longer than those in high altitude areas.The influence of altitude height on leaves thickness varied from leaf position: there was no significant difference on thickness of lower leaves among three altitude areas,whereas the thickness of middle leaves and upper leaves increased with altitude increasing.6.The influences of altitude on the routine chemical components and neutral aroma components of air-cured burley tobacco were analyzed.The results showed that the differences of total nitrogen contents in different leaf positions were not significantly among three altitude areas.The total sugar contents and restore sugar contents of upper leaves and middle leaves were significantly higher in low altitude areas than in other ones.The potassium contents of tobacco leaves were lower in middle altitude areas than in other ones while the nicotine contents showed the opposite trend.The contents of potassium and chlorine of tobacco leaves were within suitable range in three altitude areas.There were some differences on neutral aroma components contents and each component contents among different altitudes.The contents of geranyl acetone,benzaldehyde and furfural alcohol of tobacco leaves were varied with the altitude changing.The contents of carotenoid degradation products of burley tobacco leaves,such as megastigmatrienone,were lower in Enshi than in the United States,while the contents of phenylalanine degradation products and browning reactions were significantly higher in Enshi than in the United States.7.The sensory qualities of air-cured burley tobacco in different altitude areas were evaluated.The results showed that the sensory quality scores of the upper and middle leaves were highest in middle altitude areas,followed by low altitude areas,those in high altitude areas were lowest.Overall,the sufficient flavor and good fullness were achieved in Enshi burley tobacco.The middle leaves had the better sensory qualities,while the sensory qualities of upper leaves were inferior.8.The influences of altitude on the economic characters of air-cured burley tobacco were analyzed.the ye and average price of middle altitude was highest in three altitude areas.supper tobacco rate of tobacco leaf in low altitude areas was highest.on the whole,economic characters of middle altitude tobacco leaf was better than other.