Research on the Correlation between Meteorological Factors and Flue-cured Tobacco Chemical Components in Different Altitudes of Lincang Region

Na WANG，Zhengxiong ZHAO，Yuxiang BAl，Shichen Ll，Ze CHENCollege of Tobacco Science，Yunnan Agricultural University，Kunming 650201，China

Research on the Correlation between Meteorological Factors and Flue-cured Tobacco Chemical Components in Different Altitudes of Lincang Region

Na WANG*，Zhengxiong ZHAO，Yuxiang BAl，Shichen Ll，Ze CHEN
College of Tobacco Science，Yunnan Agricultural University，Kunming 650201，China

In this study，the relationship between major meteorological factors and tobacco chemical components in different altitudes of Yongde County，Lincang Region of Yunnan Province was studied using correlation analysis and path analysis methods.The results showed that there was a difference on meteorological factors in different altitudes，causing different impacts on chemical components of flue-cured tobacco；contents of nicotine and total nitrogen decreased with the rising of altitude，conversely，total sugar and reducing sugar contents increased with the rising trend of altitude，and the differences on the contents of potassium （K）and chlorine（Cl），and the ratio of K to Cl in different altitudes were not significant，at the altitude of 1 250-1 450 m，each chemical component indicator was better.The correlation between main meteorological factors and conventional chemical components of tobacco leaves was as follows:contents of reducing sugar and total sugar increased with the increase of rainfall and relative humidity，and decreased with the increase of sunshine duration；nicotine content increased with the increase of accumulated temperature and sunshine duration；total nitrogen（N）content increased with the increase of daily mean temperature and accumulated temperature；sugar-alkali ratio increased with the increase of rainfall.Path analysis showed that the direct effect of sunshine duration on reducing sugar and total sugar of tobacco leaves was faint，but the indirect effect was obvious；meanwhile，the direct and indirect effects of it on nicotine and total N were the greatest.

Altitude；Meteorological factors；Chemical components；Correlation analysis；Path analysis

Materials and Methods

Experimental time and sites

The experiment was carried out in different altitudes of Yongde County，Lincang Region of Yunnan Province in 2012，the agrotype was red soil.

Experimental material

The experimental variety was K326.

Experimental design and implementation

The experiment was carried out in such 5 altitudes of Yongde County as Yongkang（950 m），Dashan（1 250 m），Yalian（1 450 m），Banka（1 650 m）and Chonggang（1 850 m），the cultivated area of each experimental plot was 0.667 hm2.The field management and flue-cured technique were based on local high-quality flue-cured tobacco production technology.Moreover，each 2 kg of flue-cured tobacco samples B2F and C3F from each treatment were chosen for conventional chemical component analysis.

The selection of meteorological factors Such 5 meteorological factors as rainfall（X1），daily mean temperature （X2），accumulated temperature（X3），sunshine duration（X4）and relative humidity （X5）from late April to early September were selected as basic meteorological factors.The data of climatic factors of experimental plots were from Lincang Municipal Meteorological Bureau and Lincang County Meteorological Bureau.

The determination of conventional chemical components AA3 continuous flow analyzer from Germany BRAN+LUEBBE Company was used for measuring and analyzing conventional chemical components of tobacco，the operation conditions and environmental factors were based on YC/ T160-2002 Tobacco and Tobacco products Determination of Total Alkaloids Continuous Flow Method，YC/ T159-2002 Tobacco and Tobacco products Determination of Water Soluble Sugars Continuous Flow Method，YC/T22000 Tobacco and Tobacco products Determination of Total Nitrogen Continuous Flow Method，YC/T 173-2003 Tobacco and Tobacco Products Determination of Potassium Flame Photometry，and YC/T 162-2011 Tobacco and Tobacco Products Determination of Chloride Continuous Flow Method.Moreover，using reckoning algorithm，the ratios of sugar to nicotine，nitrogen to nicotine，and K to Cl，and the difference of total sugar and reducing sugar were deduced. Statistical analyses

Variance analysis， correlation analysis and path analysis were done using DPS6.55 and Excel 2003.

Results and Analyses

Comparative analysis on tobacco chemical components in different altitudes

Comparative analysis on chemical components of upper leaves of tobacco in different altitudes From Fig.1，contents of reducing sugar and total sugar in upper leaves of tobacco both decreased firstly and then increased with the rising of altitude，the minimum value of the two both appeared at 1 250 m and respectively reached 21.03%and 23.61%；nicotine contents decreased with the rising of altitude；however，the ratio of sugar to nicotine increased with the rising of altitude；the changing rules of total N contents and the ratio of nitrogen to nicotine were not obvious；K contents decreased at first and then increased with the rising of altitude，and the minimum value appeared at 1 450 m，and reached 1.21%；the changing rule of Cl contents was not apparent，but at 1 250 m，the minimum value was 0.83%；the changing rule of the ratio of K to Cl also was not obvious，and the maximum value was 22.19 at 1 250 m.

Comparative analysis on chemical components of middle leaves of tobacco in different altitudes As shown in Fig.1，contents of reducing sugar in middle leaves of tobacco increased firstly and then decreased with the rising of altitude，and the peak value was 30.51%at 1 650 m，there were significant differences among different altitudes；total sugar contents increased with the rising of altitude；nicotine contents decreased at first and then increased with the rising of altitude，and the minimum value was 2.12%at the altitude of 1 650 m；total N contents decreased with the rising of altitude；the ratio of sugar to nicotine also decreased with the rising of altitude，and the peak value was 17.62 at the altitude of 1 650 m；the changing rules of the ratio of nitrogen to nicotine and Cl contents were not obvious；K contents showed decreasing trend firstly and then increased with the rising of altitude，and the minimum value was 1.09%at 1 650 m；the changing rule of the ratio of K to Cl was not obvious，and the maximum value was 16.45 at the altitude of 1 250 m.

Table 1 Meteorological factor indicators of each experiment site during the field period in 2012

Comparing the suitable range［10］of chemical components of high-quality tobacco in Yunnan Province，we found that contents of reducing sugarand total sugar，as well as the ratio of sugar to nicotine were all higher in different altitudes，which may be determined by local special climate and soil conditions.In general，each chemical component indicator was better at the altitude of 1 250-1 450 m.Hu Guosong［7］，Chen Yongming［8］et al.proved that the quality of tobacco was the best at the altitude of 1 250 and 1 450 m.

Analysis on the correlation between meteorological factors and chemical components of tobacco leaves The correlation between meteorological factors and chemical components of upper leaves of tobacco

As seen in Table 2，we drew the conclusion that reducing sugar content in upper leaves of tobacco had significant positive correlation with relative humidity and rainfall，and their correlation coefficients were 0.89 and 0.87，respectively；conversely，it was significantly and negatively correlated with sunshine duration，and the correlation coefficient was-0.87，indicating that reducing sugar content in upper leaves of tobacco increased with the increase of relative humidity and rainfall，and decreased with the increase of sunshine duration.Total sugar also had significant positive correlation with relative humidity and rainfall，and the correlation coefficients were 0.85 and 0.80，respectively.Nicotine showed extremely significant positive correlation with sunshine duration and the correlation coefficient was 0.97，but had extremely significant negative correlation with rainfall，and the correlation coefficient was-0.97.Total N was significantly and positively correlated with daily mean temperature and accumulated temperature，and both of the correlation coefficients were 0.93. The ratio of sugar to nicotine which reflects acid-base equilibrium of tobacco had extremely significant positive correlation with rainfall and relative humidity，and the correlation coefficients were 0.96 and 0.98，respectively.

The correlation between meteorological factors and chemical components of middle leaves of tobacco Reducing sugar content in middle leaves of tobacco showed significant positive correlation with rainfall and relative humidity，and their correlation coefficients were 0.87 and 0.83，respectively，on the contrary，it was significantly and negatively correlated with sunshine duration，thus the rule was the same as the upper-stalk tobacco，that is，reducing sugar content in middle leaves of tobacco increased with the increase of rainfall and relative humidity，and decreased with the increase of sunshine duration.There was extremely significant positive correlation between total sugar and rainfall，and the correlation coefficient was0.95，total sugar also showed significant positive correlation with relative humidity；conversely，it had extremely significant negative correlation with daily mean temperature and accumulated temperature，and showed significant negative correlation with sunshine duration.Nicotine was significantly and positively correlated with daily mean temperature and accumulated temperature，but it was significantly and negatively related to sunshine duration.Total N was significantly and positively correlated with daily mean temperature and accumulated temperature，and their correlation coefficients were 0.96 and 0.95；moreover，it was significantly and negatively related to rainfall.The ratio of sugar to nicotine had extremely significant positive correlation with rainfall，showing that as the rainfall increased，the ratio of sugar to nicotine would increase.

Table 2 Analysis on the correlation between meteorological factors and conventional chemical components of tobacco leaves in different altitudes

In conclusion，from the correlation between meteorological factors and chemical components of upper-stalk and middle tobacco leaves，reducing sugar and total sugar contents had great correlation with relative humidity，rainfall and sunshine duration，namely，they were proportional to rainfall and relative humidity，and inversely proportional to sunshine duration.Nicotine content was greatly correlated with accumulated temperature and sunshine duration，more specifically，nicotine had a proportional relationship with the two.Total N showed a larger correlation with daily mean temperature and accumulated temperature，that is，total N increased with the increase of the two.The ratio of sugar to nicotine was largely related to rainfall，and their relationship was also proportional.

The path analysis between meteorological factors and chemical components of tobacco leaves

From the above，there was certain correlation between meteorological factors and conventional chemical components.To make clear the direct and indirect effects of meteorological factors on conventional chemical components，the path analysis was carried out for meteorological factors and conventional chemical components.

The path analysis between meteorological factors and chemical components of upper leaves of tobacco From Table 3，the direct effect of each meteorological factor on reducing sugar of upper leaves of tobacco was unequal in a descending order as:relative humidity＞accumulated temperature＞rainfall＞daily mean temperature＞sunshine duration，in which relative humidity and rainfall had positive effect，and the others had negative effect，which was consistent with the above correlation analysis；the sum of indirect effects was as follows:accumulated temperature＞sunshine duration＞rainfall＞relative humidity＞daily mean temperature；from the function of view，rainfall，sunshine duration and accumulated temperature played an indirect effect through relative humidity，and daily mean temperature and relative humidity played an indirect effect by accumulated temperature.

The direct effect of meteorological factors on total sugar contents of upper leaves of tobacco was:rainfall＞relative humidity＞accumulated temperature＞daily mean temperature＞sunshine duration；the sum of the indirect effects showed as follows:sunshine duration＞accumulated temperature＞rainfall＞relative humidity＞daily mean temperature；for the function，accumulated temperature and sunshine duration played an indirect effect by rainfall，and rainfall，daily mean temperature and relative humidity had indirect effect through sunshine duration.

The direct effect of meteorological factors on nicotine content of upper leaves of tobacco was as follows: daily mean temperature＞sunshine duration＞accumulated temperature＞rainfall＞relative humidity；and the indirect effect was:sunshine duration＞accumulated temperature＞daily mean temperature＞rainfall＞relative humidity；from the view of function，relative humidity，daily mean temperature，accumulated temperature and sunshine duration had indirect effect through relative humidity，and relative humidity played the indirect effect by rainfall.

The direct effect of meteorological factors on total N of upper leaves of tobacco was sunshine duration＞daily mean temperature＞rainfall＞accumulated temperature＞relative humidity，in which the direct effect of relative humidity was 0，that is，it had no direct effect on total N of upper-stalk tobacco；the sum of indirect effect indicated as follows:sunshine duration＞accumulated temperature＞relative humidi-ty＞rainfall＞daily mean temperature；from the function of view，rainfall and accumulated temperature played an indirect effect through daily mean temperature，and daily mean temperature，sunshine duration and relative humidity had indirect effect by rainfall，however，relative humidity had no indirect effect on other meteorological factors.

Table 3 The path analysis between meteorological factors and chemical components of upper leaves of tobacco in different altitudes

The path analysis between meteorological factors and chemical components of middle leaves of tobaco As seen in Table 4，the direct effect of meteorological factors on reducing sugar content of middle leaves of tobacco was:relative humidity＞rainfall＞accumulated temperature＞sunshine duration＞daily mean temperature；the indirect effect was:sunshine duration＞daily mean temperature＞rainfall＞accumulated temperature＞relative humidity；from the function of view，sunshine duration had indirect effect through relative humidity，and rainfall，daily mean temperature，accumulated temperature and relative humidity played their indirect effect by sunshine duration.

The direct effect of meteorological factors on total sugar of middle leaves of tobacco was as follows:relative humidity＞rainfall＞accumulated temperature＞sunshine duration＞daily mean temperature；and the indirect effect was:sunshine duration＞daily mean temperature＞relative humidity＞accumulated temperature＞rainfall；from the view of function，rainfall and relative humidity had indirect effect through sunshine duration，and daily mean temperature，accumulated temperature and sunshine duration played an indirect effect by rainfall.

The direct effect of meteorological factors on nicotine of middle leaves of tobacco was as follows:sunshine duration＞rainfall and relative humidity＞accumulated temperature＞daily mean temperature；and the indirect effect was:sunshine duration＞daily mean temperature＞accumulated temperature＞relative humidity＞rainfall；from the view of function，sunshine duration played an indirect effect by relative humidity，and rainfall，daily mean temperature，accumulated temperature and relative humidity had indirect effect though sunshine duration.

The direct effect of meteorological factors on total N of middle leaves of tobacco was as follows:sunshine duration＞relative humidity＞rainfall＞accumulated temperature＞daily mean temperature；the indirect effect was:sunshine duration＞daily mean temperature＞accumulated temperature＞relative humidity＞rainfall；thereinto，sunshine duration had the greatest contribution directly and indirectly，namely，1.74 and 2.43，respectively；from the view of function，rainfall，daily mean temperature，accumulated temperature and relative humidity all had indirect effect though sunshine duration，and sunshine duration played an indirect effect by relative humidity.

Based on the above analysis，relative humidity and rainfall had greater direct effect on contents of reducing sugar and total sugar，however，sunshine duration had obvious indirect effect on them；moreover，sunshine duration directly and indirectly had the greatest effect on nicotine and total N contents.

Discussion

Most of Lincang tobacco regions in Yunnan Province belong to high altitude areas，there are different meteorological factors in different altitudes，affecting chemical components of tobacco.The change of altitude will affect the whole metabolic process of tobacco plant，thereby affecting different chemical components in tobacco［11］.

Effect of altitude on chemical components of tobacco

Table 4 The path analysis between meteorological factors and chemical components of middle leaves of tobacco in different altitudes

Combined with the indexes of conventional chemical components of sound tobacco in Yunnan Province［10］，the test results showed that each chemical component indicator of to bacco was better at the altitude of 1 250-1 450 m.Li Hongxun et al.［2］showed that contents of total sugar and reducing sugar increased with the rising of altitude，and reached significant level；nicotine and total N contents decreased with the rising of altitude；when planting tobacco at the altitude of 1 400-1 600 m，main chemical components of tobacco were coordinated and the usability was high. This may be generated by the climate and topography of different regions. Shigenobu M.［12］also studied that nicotine contents decreased with the rising of altitude，this may be caused by the change of meteorological factors at the high altitude，generating the decline of synthetase activity of nicotine；at the same time，the rising of altitude may cause the change of temperature difference between day and night and the amount of solar radiation，which inhibited the synthesis of nicotine.

Effect of meteorological factors on chemical components of tobacco in different altitudes

Based on the test results，it proved that daily mean temperature and accumulated temperature had negative effect on the contents of reducing sugar and total sugar of tobacco，however，sunshine duration had positive effect on nicotine and total N. This had subtle differences with previous study，but they were basically the same.Wei Chengcai et al.［13］researched the relationship between tobacco quality and meteorology of Southern Shaanxi，and found that total sugar and reducing sugar had significant negative correlation with average temperature during the field period；Shi Junxiong［14］suggested that total sunshine duration had significant negative correlation with reducing sugar content of tobacco，excessive sunshine duration was unfavourable to reducing sugar accumulation.

The correlation between meteorological factors and chemical components of tobacco

The direct and indirect effects of meteorological factors on conventional chemical component of tobacco showed that the direct effect of sunshine duration on reducing sugar and total sugar was less，however，the indirect effect was greater；and its direct and indirect effects on nicotine and total N were both greater.This indicated that sunshine duration had great influence on the formation of tobacco chemical quality.Xie Jingming et al.［15］showed that sunshine duration was the main meteorological factors affecting sound tobacco.Junhong MA［16］demonstrated that sunshine duration，temperature and rainfall were the important factors for tobacco quality and tobacco characteristic formation.Ding Gensheng［17］proved that the content of carbohydrate in tobacco was mostly and directly affected by daily mean temperature during the field period，followed by rainfall，the direct effect of sunshine duration was less.The results had a slight difference with Wang Xiaoguo’s research［18］，but they were basically consistent，he studied that the correlation between main climatic factors and chemical component of tobacco was as follows:temperature＞sunshine＞rainfall.

Different altitudes have different effects on meteorological factors，thereby affecting the growth and development，output and quality of tobacco.What’s more，the inner quality itself of tobacco has the characteristics of multi-factor，multiple variations and difficult to fix quantity.Different meteorological factors have different effects on tobacco quality，and even in thesame altitude，every meteorological factor interacts with each other，moreover，their relationship with other ecological factors like soil，microorganism，fertilizer and field microclimate is complicated，which affects the growth of tobacco and the chemical component，the specific conditions remain to be further studied.

Conclusion

In different altitudes，there were apparent differences in the contents of total sugar，reducing sugar，nicotine and total N in different parts of tobacco.In general，nicotine and total N showed declining trend with the rising of altitude；conversely，total sugar and reducing sugar presented rising trend with the rising of altitude；the differences of the contents of Cl and K，as well as the ratio of K to Cl in different altitudes were not obvious.Each chemical component indicator was better at the altitude of 1 250-1 450 m.

From the correlation between chemical components and meteorological factors，in Yongde County of Lincang，the contents of total sugar and reducing sugar in flue-cured tobacco leaves increased with the increase of rainfall and relative humidity；nicotine increased with the increase of accumulated temperature and sunshine hours；total N increased with the increase of daily mean temperature and accumulated temperature；and the ratio of sugar to alkali increased with the increase of rainfall.

Through the path analysis between main meteorological factors and chemical components during the field period，the results showed that relative humidity and rainfall had direct action on the contents of total sugar and reducing sugar，however，sunshine duration had greater indirect effect on the two；meanwhile，the direct and indirect effects of sunshine duration on nicotine and total N were the greatest.

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Responsible editor:Nanling WANG

Responsible proofreader:Xiaoyan WU

不同海拔高度气象因子与临沧地区烤烟化学成分相关性研究

王娜*，赵正雄，白羽祥，李世琛，陈泽 （云南农业大学烟草学院，云南昆明 650201）

运用相关分析和通径分析方法，对云南省临沧永德县不同海拔高度主要气象因子与烟叶常规化学成分含量的关系进行了研究。结果表明，不同海拔高度的气象因子存在差异，对烤烟的常规化学成分产生不同影响；烟碱和总氮随着海拔升高而减少，总糖和还原糖随海拔高度升高呈现上升趋势，钾和氯的含量、以及钾氯比不同海拔高度间差异不显著，各化学成分指标在海拔1 250-1 450 m处表现较佳。主要气象因子与烟叶常规化学成分的相关性为：还原糖、总糖随降雨量和相对湿度增加而增加，随日照时数增加而减少；烟碱随积温、日照时数增加而增加；总氮随日均温、积温增加而增加；糖碱比随降雨量增加而增加。通径分析表明：日照时数对烟叶的还原糖、总糖直接影响较小，而间接影响较大；对烟碱、总氮的直接和间接影响均最大。

海拔；气象因子；化学成分；相关分析；通径分析

A lthough tobacco has extensive adaptability，it is sensitive to environment，the change of ecological condition will have an impact on tobacco yield and quality.Different altitudes have created different ecological types.With the change of altitude，amount of solar radiation，effective accumulative temperature，temperature difference between day and night，and air humidity will change，thereby affecting the chemical components of tobacco［1］.Even in the same altitude，the effect of meteorological factors on flue-cured tobacco quality is considerably greater than the effect of soil agrochemistry and agrotype［2］. Recently，many researches have shown that altitude has significant influence on sound tobacco production，Chen Chuanmeng［3］，Lu Yongheng et al.［4］proved that with the rising of altitude，the growth rate of tobacco plant slowed.Jian Yongxing et al.［5］showed that along with the rising of altitude，oil content in flue-cured tobacco increased，the quality improved，the percentage of first-class tobacco also increased，moreover，exterior and inherent qualities of flue-cured tobacco both improved.However，Mu Biao et al.［6］indicated that in high altitude areas，overall score of appearance quality，interior quality，and the color，aroma and taste all decreased with the rising of altitude.Hu Guosong［7］，Chen Yongming［8］，Yi Jianhua［9］et al.studied that total nitrogen（N）and nicotine con-tents in tobacco leaves decreased with the rising of altitude，conversely，reducing sugar and potassium （K）contents increased with the rising of altitude.In view of different opinions in different literatures，we started from meteorological factors of different altitudes，studied its relationship with conventional chemical components of tobacco，to seek the relationship between altitude and tobacco quality，and clarify the main meteorological factors restricting sound tobacco quality in different meteorological altitudes，providing a theoretical basis and technological support for the optimal layout of new tobacco production areas in Lincang.

王娜（1979-），女，云南楚雄人，讲师，在读博士，主要从事烟草栽培相关研究，E-mail：cindy_0725@126.com。

2014-12-19

2015-02-28

.E-mail:cindy_0725@126.com

December 19，2014Accepted:February 28，2015