Relationships Between Soil Ecological Factors And The Contents Of Neutral Aroma Components In Flue-cured Tobacco Leaves In Nanyang Tobacco-growing Areas

13 test sites were chosen from 6 main tobacco-growing counties in Nanyang city at 2006. The method of factor analysis and canonical correlation analysis were employed to study the relationships between neutral aroma components in different stalk positions of flue-cured tobacco leaves and soil physiochemical characteristics and microbes contents and enzymes activities in different soil ecology conditions. And the results were as following:1. Total description of contents of neutral aroma components in flue-cured tobacco leaves in Nanyang tobacco-growing areas.The contents of products degraded by phenylalanine, browning reaction substances, products degraded by cembrane and total contents of neutral aroma components except neophytadiene in flue-cured tobacco leaves had no distinct divergence in different stalk positions. The contents of products degraded by carotenoid and neophytadiene were distinctly higher in lower leaves than in upper leaves. The contents of them had no distinct divergence between lower leaves and cutters, and there were no distinct divergence between upper leaves and cutters. The coefficient of variation of products degraded by cembrane was the highest in all three stalk positions. And the coefficient of variation of total contents of neutral aroma components except neophytadiene was the least.2. Total description of soil nutrients in Nanyang tobacco-growing areas.The coefficients of soil available nutrients except available nitrogen and total phosphorus were much higher than the others. The coefficients of soil volume weight, density and porosity were much lower than the others. It shows that the soil physical characteristics had no distinct divergence in Nanyang tobacco-growing areas.3. The relationships between physiochemical characteristics of soil and total contents of neutral aroma components in flue-cured tobacco leaves in Nanyang tobacco-growing areas.Canonical correlation analysis was done on the relations between physiochemical characteristics of soil and total contents of neutral aroma components in flue-cured tobacco leaves in Nanyang tobacco-growing areas. The canonical correlation analysis showed that the soil density was highly positively correlated with the contents of 2-isopropyl-5-ketonhexanal in upper leaves of flue-cured tobacco. The contents of soil available phosphorus were highly negatively correlated with the contents of 2-isopropyl-5-ketonhexanal in lower leaves and cutters of flue-cured tobacco. The contents of soil active carbon, total organic carbon, organic matter and soil volume weight were highly positively correlated with the contents of 3,4-dimethyl-2,5-furandiketone in lower leaves of flue-cured tobacco. Contrarily the soil porosity was negatively correlated with the latter.4. The relationships between contents of soil microbes and total contents of neutral aroma components in flue-cured tobacco leaves in Nanyang tobacco-growing areas.Canonical correlation analysis was done on the relations between contents of soil microbes and total contents of neutral aroma components in flue-cured tobacco leaves in Nanyang tobacco-growing areas. The canonical correlation analysis showed that the contents of soil phosphobacteria were highly positively correlated with the contents of 2-isopropyl-5-ketonhexanal in upper leaves and solanone in lower leaves of flue-cured tobacco. Contrarily the former was negatively correlated with the contents of 4-yinyle-2-methoxyphenol in lower leaves of flue-cured tobacco. The contents of soil bacillus were highly positively correlated with the contents of solanone in cutters of flue-cured tobacco. Contrarily the former was negatively correlated with the contents of 4-yinyle-2-methoxyphenol in cutters of flue-cured tobacco. The contents of soil cellulolytic microbes were highly positively correlated with the contents of 4 diastereomers of megastigmatrienone, 3-hydroxyl-β-damascone,β-damascenone,β-dihydroionone and neophytadien in cutters of flue-cured tobacco.5. The relationships between activity of soil enzymes and total contents of neutral aroma components in flue-cured tobacco leaves in Nanyang tobacco-growing areas.Canonical correlation analysis was done on the relations between activity of soil enzymes and total contents of neutral aroma components in flue-cured tobacco leaves in Nanyang tobacco-growing areas. The canonical correlation analysis showed that the activity of soil amylase was highly positively correlated with the contents of 4-yinyle-2-methoxyphenol and 2-isopropyl-5-ketonhexanal in upper leaves of flue-cured tobacco. Contrarily the former was negatively correlated with the contents of solanone in upper leaves of flue-cured tobacco. The activity of soil amylase was highly negatively correlated with the contents of 5-methyl-2-furfural, 6-methyl-2-heptanone, benzyl alcohol, phenylethanol, benzaldehyde andβ-ionone in cutters of flue-cured tobacco. Contrarily the former was positively correlated with the contents of 3-methyl-2-crononaldehyde in cutters of flue-cured tobacco.