Changes of Granule Structure and Enzyme Hydrolysability of Starch in Upper Flue-cured Tobacco Leaves During Bulk Flue-curing

[Objective] This study aimed to investigate the changes of granule struc- ture, characteristic and related enzymatic activity of starch in upper flue-cured tobac- co leaves during bulk flue-curing process, to provide theoretical basis for reasonably regulating the starch content in upper flue-cured tobacco leaves and improving the quality of upper flue-cured tobacco leaves. [Method] Changes of amylase activity, enzyme hydrolysability and granule structure of starch in upper flue-cured tobacco leaves were studied during flue-curing process using conventional physical and chemical analysis and SEM. [Result] During the flue-curing process, the starch con- tent of tobacco leaves changed greatly at yellowing stage, and the activity of amy- lase presented the double-peak curve. The SEM observation results showed that most of the starch granules in fresh tobacco leaves were spheroidal and long cylin- drical, while some individuals were in irregular shape, with obvious groove-like in- vagination and layered structure on granule surface; during the flue-curing process, a large amount of starch granules showed layered structure on the surface at yellow- ing stage, and the long cylindrical starch granules were reduced greatly; at the end of flue-curing, there were barely any long cylindrical starch granule in flue-cured to- bacco leaves. Average long-axis-diameter of starch granules in fresh tobacco leaves was 3.21 μm, showing an overall gradually increasing trend during the flue-curing process, which was significantly enhanced at 38 and 42 ℃. The diameter of starch granules increased by more than 60% at the end of 42 ℃ and there was no re- markable difference after 47 ℃. During the flue-curing process, enzyme hydrolysabil- ity of starch in flue-cured tobacco leaves first increased, reached a peak at 38 ~C, and then decreased. [Conclusion] During the bulk flue-curing, the yellowing stage is the critical period for starch content, granule structure and characteristic changes of flue-cured tobacco leaves, it is of positive effects to improve the quality of upper flue-cured tobacco leaves by regulating the flue-curing conditions at yellowing stage.

Effects of Exogenous Amylases and Metal Ions on the Amylase Specific Activities and Starch Degradation of the Upper Leaves of ‘KRK_(26)' during Flue-curing

Objective] The aim of this study was to investigate the effects of exoge-nous amylases and Ca2＋, Mn2＋ and K＋ on the amylase specific activities and starch degradation of the upper leaves of ＇KRK26＇ planted in Yunnan Province during flue-curing. [Method] The amylase specific activities and starch degradation of the leaves were determined by using spectrophotometry. [Result] The 8 U/g exogenous α-amy-lase could improve the specific activity of the leaf α-amylase at yel owing and color-fixing stages, but could not at stem-drying stage, and similarly, the 80 U/g exoge-nous β-amylase could improved the specific activity of the leaf β-amylase at the yel owing stage and the early period of color-fixing stage. The leaf starch could be enhanced to degrade by the exogenous α- or β-amylases and the enhancing effect of the former was stronger than that of the later. 1.50 mg/ml Ca2＋ improved the specific activity of the leaf （α＋β）-amylase mainly due to its enhancing effect on the leaf α-amylase, and increased the starch degradation. 4 mmol/L Mn2＋ inhibited the leaf α-amylase from yel owing to the early period of color-fixing and the β- and （α＋β）-amylases from the yel owing to the later period of color-fixing, but enhanced the leafα-amylase from the later period of color-fixing to the later period of stem-drying and the β- and （α＋β）-amylases at the later period of stem-drying. Meanwhile, Mn2＋ ham-pered the starch degradation during yel owing, but promoted it from the early period of color-fixing to stem-drying. 1 mg/ml K＋ enhanced the leaf α-, β- and （α＋β）-amy-lases during the yel owing stage, but lowered them from the early period of color-fix-ing to the later period of stem-drying, and always inhibited the leaf starch degrada-tion. [Conclusion] The exogenous α-, β- amylases and Ca2＋ of suitable concentra-tions could be used to treat the tobacco leaves before flue-curing to improve the leaf starch degradation during the curing.

Studies on Amylase and Degradation of Starch and Pigment of Tobacco Leaf During Process of Flue-Curing

The changes in the activity of amylase and amylase-isoenzyme and the degradation of starch and pigment of tobacco leaf during flue-curing were studied by using the electric- heated flue-curing barn designed and made by the Henan Agricultural University. The temperature and humidity of the barn were controlled automatically. The results indicated that starch in tobacco leaf decreased rapidly and leveled off after 48 h of curring, in the meantime, the content of soluble sugar increased accordingly and reached a peak at the stage of color-fixing. Both of them had a rapid-changing stage in the first 36 hours of yellowing. The changes of starch and soluble sugar contents had highly significant negative-correlation at 1 % level (rNC89 = -0.8962**, rYY85 = -0.9704**). The activity of amylase increased with the proceeding of curing and reached a peak after 36 hours of curing, then decreased. But the activity of amylase kept at a high level when the humidity of curing-environment was very low, even if the tobacco leaf had been dried. The rapid degradation of starch showed a significantly negative correlation with the increase of activity of amylase at 5 % level (rNC89 = -0.8495*, rYY85 = -0.7839*). The degradation of starch and pigment had the same regulation and had highly significant correlation at 1 % level (rNC89= 0.9649**, rYY85= 0.9428**). There were mainly three amylase-isoenzyme bands -A, B, C respectively, in tobacco leaf during flue curing. They were identified as α-AMY, β-AMY, R-AMY, and the activity of β-AMY was the highest. The changes in amylase activity and contents of starch and pigment were affected by the tobacco leaf moisture and environmental humidity during curing.

Effect of Different Flue-curing Techniques on the Taste and Aroma Substances of Tobacco Leaves

[Objective]This study aimed to optimize the conditions for curing tobacco leaf, so as to improve its flavor and quality. [Method] Leaves of Yuanyan 87 were col ected and cured by three different techniques （moderate-intensity conditions throughout the curing course; high-intensity conditions at leaf yel owing and wilting stages, moderate-intensity conditions at leaf drying and vein drying stages; high-in-tensity conditions throughout the curing course）, and then the contents of 48 aroma substances and taste indices of the finished tobacco leaves were measured. [Result] The contents of 28 aroma substances in the tobacco leaves cured under high-inten-sity conditions throughout the course were higher and the taste indices of these to-bacco leaves were better, compared with those flue-cured by the other two tech-niques. The contents of the other 20 aroma substances were not significantly af-fected by the curing techniques. The second best technique was high-intensity con-ditions at leaf yel owing and wilting stages and moderate-intensity conditions at leaf drying and vein drying stages. Curing tobacco leaves at moderate-intensity condi-tions throughout the course was the worst one. [Conclusion] Compared with the oth-er two methods, the contents of aroma substances and taste indices of the tobacco leaves cured under high-intensive conditions throughout the course were the best.

Changes of Polyphenols in Tobacco Leaves During the Flue-Curing Process and Correlation Analysis on Some Chemical Components

The changes of polyphenols in tobacco leaves during the flue-curing process and correlation analysis on some chemical components were studied. Leaf samples were taken from different tobacco-producing regions in Henan Province, China. The results indicated that the content of total phenols increased during the first 24 h of curing, and then decreased. It reached the lowest value at 72 h of curing and increased rapidly after that. The content of chlorogenic acid also increased during 0-24 h of curing. But the lowest point occurred at 60 or 72 h of curing and then it increased till the end of the curing process. The content of mtin generally increased with curing, and showed little fluctuations. The changes of PPO and POD activity were the opposite. Rutin was found to have a highly significant positive correlation with total sugar （r=0.822^＊＊）, but a highly significant negative correlation with starch, nicotine, and protein.

Effects of Different Flue-curing Technologies on Microscopic Structure of Flue-cured Tobacco Leaves

[Objective] This study aimed to compare the effects of Chinese quality-improving fragrunce-increasing tobacco flue-curing technology, Chinese three- stage tobaeeo flue-curing technology and Zimbabwean tobaceo flue-euring technology on microscopie structure of flue-cured tobacco leaves to provide theoretical basis for tobacco flue-curing. [ Method ] Middle leaves of tobacco cultivar K326 were collected in Pengshui County of Chongqing City for flue-curing experiment using three flue-curing technologies. Leaf samples were collected regularly in the flue-curing process, to investigate the microscopic structure of flue-cured tobaceo leaves. [ Result] During three flue-curing processes, leaves, palisade tissues and sponge tissues shrank gradually. Three flue-euring processes exhibited significant differ- ences in the peak of tissue shrinkage ： microscopic structure of flue-cured tobacco leaves in Chinese three-stage tobacco flue-curing process shrank earliest, follower by Chinese quality-improving fragrance-increasing tobacco flue-curing process; flue-eured tobacco leaves in Zimbabwean tobacco flue-curing process presented the latest shrinkage. At 84 h post-curing, leaf thickness in three flue-curing processes showed a descend order of Chinese three-stage tobacco flue-curing process 〉 Chinese quality-improving fragrance-increasing tobacco flue-curing process 〉 Zimbabwean tobacco flue-curing process. Upper and lower epidermal cells in Zimb- abwean tobacco flue-curing process ruptured earlier than other two flue-curing processes; eventually, the majority of cells ruptured and mixed with palisade tissues and sponge tissues. In Chinese quality-improving fragranee-increasing tobacco flue-curing process, only a small number of epidermal cells in dried leaves ruptured. Among three flue-curing technologies, Zimbabwean tobacco flue-curing technology exhibited the greatest damage to epidermal cells, followed by Chinese three-stage tobaceo flue-curing technology; Chinese quality-improving fragrance-increasing tobacco flue-curing technology had the minimum damage to epidermal cells. Mese- phyll cross-section exhibited significant morphological changes in stomata. To be specific, at 0 - 12 h post-curing, stomata of tobacco leaves closed with slightly prominent stamatal apparatuses on upper and lower epidermis; at 24 -72 h post-curing, stomata of tobaceo leaves changed gradually from opening to closure with significantly prominent stomatal apparatuses on upper and lower epidermis; at 84 h post-curing, stomata of tobacco leaves closed, and the majority of stomatal appa- ratuses were significantly prominent. In Chinese quality-improving fragrance-increasing tobacco flue-curing process, only a small number of epidermal ceils ruptured at 84 h pest-flue-curing; palisade tissues and sponge tissues shrank almost simultaneously. Significant gaps were observed between palisade tissues and between pal- isade tissues and sponge tissues. Chinese quality-improving fragrance-increasing tobacco flue-curing technology exhibited lower disorder level compared with other two flue-curing technologies. [ Conclusion] Chinese quality-improving fragrance-increasing tobacco flue-curlng technology was conducive to maintaining the micro- scopic structure integrity of flue-cured tobacco leaves and obtaining high-quality flue-cured tobacco leaves.

Effects of Different Flue-curing Technologies on Submicroscopic Structure of Flue-cured Tobacco Leaves

[ Objective] This study aimed to compare the effects of low-temperature low-humidity tobacco flue-curing technology, moderate-temperature moderate- humidity tobacco flue-curing technology and moderate-temperature high-humidity tobacco flue-curing technology on submicroscopic structure of flue-cured tobacco leaves to provide theoretical basis for tobacco flue-curing. [ Method] Middle leaves of tobacco cuhivar K326 were collected in Pengshui County of Chongqing City for flue-curing experiment using three flue-curing technologies. Leaf samples were collected regularly in the flue-curing process, to investigate the submicroscopic structure of flue-cured tobacco leaves. [ Result] Morphology changes and structural rupture of chloroplasts occurred at different time during three flue-curing proces- ses. In low-temperature low-humidity flue-curing process, morphology changes and structural rupture of chloroplasts occurred late but rapidly; in moderate-tempera- ture moderate-humidity flue-curing process and moderate-temperature high-humidity flue-curing process, morphology changes and structural rupture of chloroplasts occurred early but slowly. Among these three flue-curing processes, the speed of changes in mitochondria morphology, cristae number and membrane rupture pres- ented an upward order of low-temperature low-humidity flue-curing process 〈 moderate-temperature high-humidity flue-curlng process 〈 moderate-temperature moderate-humidity flue-curing process. In low-temperature low-humldity flue-curing process, starch granules in chloroplasts ruptured after flue-curing for 36 -48 h ; in moderate-temperature moderate-humidity flue-curing process, starch granules in chloroplasts ruptured after flue-curing for 24 - 36 h; in moderate-temperature high-humidity flue-curing process, starch granules in chloroplasts ruptured after flue-curing for 12 - 24 h. [ Conclusion ] Using low-temperature low-humidity flue- curing technology could prolong the maintenance duration of the submicroscopic structure integrity of flue-cured tobacco leaves, which was conducive to fully decom- posing and transforming substances in tobacco leaves and obtaining high-quality flue-cured tobacco leaves.

The Quality Difference of Tobacco Leaves Between Different Flue-curing Processes in Honghe Tobacco-growing Area

[Objectives] This study was conducted to compare the effects of different curing processes,in order to optimize the local supporting intensive fluecuring process.[Methods] A comparative experiment was carried out in Mile,Luxi and Jianshui on the four-layer tobacco-packed intensive curing process(K1)and the eight-point precise and intensive curing process(K2).[Results]The results showed that according to the appearance evaluation of the tobacco leaves,K1 was higher than K2 in respective scores of color,maturity,leaf structure and defects and the total score,while K1 equaled K2 in the scores of identity,oil content,chroma and length.The differences in respective scores of the two processes were not significant.According to the results of sensory evaluation,the two tobacco enterprises got different evaluation results of unblended cigarettes made of the middle leaves due to different raw material requirements of the enterprises by different processes.K1 was higher than K2 in the sensory evaluation of China Tobacco Yunnan Industrial Co.,Ltd.,while it was lower than K2 in that of China Tobacco Zhejiang Industrial Co.,Ltd.,and the difference in the total score between the two processes was significant.From the content of chemical components,in the conventional chemical component contents including total sugar,reducing sugar,chlorine and starch,K1 was higher than K2,while in the contents of potassium,total phytonine,total nitrogen and petroleum ether extract,K1 was lower than K2,but the differences were not significant.K1 was lower than K2 in the contents of neutral aroma components including ketones,alcohols,aldehydes,heterocyclics,neophytadiene and total content,while K1 was higher than K2 in the contents of esters,phenols,but the respective differences were not significant.Except the significant difference in the total score in the sensory evaluation of China Tobacco Zhejiang Industrial Co.,Ltd.,there were no significant differences in other items in the appearance evaluation,sensory evaluation and chemical composition of tobacco leaves between K1 and K2.[Conclusions] The supporting intensive curing process can be further optimized on the basis of this study.

Effects of Different Flue-curing Barns on Aroma Quality of Upper Flue-cured Tobacco Leaves of K326

[Objective] This study was conducted to compare the aroma quality of up-per leaves of K326 flue-cured in different barns, and provide theoretical references for the development and optimization of bulk curing barn and the supporting tech-niques. [Method] The upper leaves of K326 were flue-cured in a commonness barn, a four-shelf bulk curing barn and a three-shelf bulk curing barn separately, and then the contents of aroma components and taste quality indices of the finished leaves were measured and compared. [Result] The contents of total aroma components, chromoplast pigment degradation products, phenylalanine aroma components and neophytadiene showed no significant differences in the leaves flue-cured in four-shelf bulk curing barn and commonness barn, but were significantly or very significantly higher than those in the leaves flue-cured in three-shelf bulk curing barn. The con-tents of carotenoid degradation products, Mail ard reaction products, cembranes aro-ma components and total aroma components （except neophytadiene） showed no significant difference among the three treatments. The results of sensory evaluation revealed that the sensory taste of the leaves flue-cured in four-shelf bulk curing barn was the best, as the finished leaves had rich, delicate aroma, comfortable and clean aftertaste. The leaves flue-cured in commonness barn was better than those flue-cured in three-shelf bulk curing barn in aroma quality, amount and aftertaste. [Conclusion] The four-shelf bulk curing barn had a large volume for tobacco leaf processing, but a similar baking environment to the commonness barn, which is conducive to the formation and accumulation of aroma components, so the finished leaves had similar appearance and quality with those flue-cured in commonness barn. The upper flue-cured leaves in three-shelf bulk curing bran had poorer quality than those flue-cured in the other two barns.

Three-Stage Six-Step Flue-Curing Technology for Viginia Tobacco Leaves and Its Application in China

In order to overcome the problem that the leaf yellowing stage in tobacco curing reduces the fragrance of the product, this study introduced the principle and key parameters of a three-stage six-step curing technology. The field trail was conducted in Wulong county of Chongqing city in 2010, and Virginia K326 was the tested cultivar. The middle leaves were harvested and plaited after maturity, and then cured with the three-stage six-step curing technology and traditional three-stage curing technology, respectively. Three replicates were established for each of the two curing technologies. Then, chemical constituents, aromatic substances and smoking quality were analyzed. The results show that compared with the traditional three-stage curing technology, the three-stage six-step curing technology produces more suitable ratios of chemical constituents, higher aromatic component content and higher smoking quality grade of tobacco leaves. Therefore, the continuous improvement of corollary equipment and matching technologies is expected to widen the applications of the three-stage six-step curing technology in tobacco and provide a strong technical support for the development of the tobacco industry.

Application of tobacco stems briquetting in tobacco flue-curing in rural area of China

To reduce the conventional energy consumption in rural area of China,tobacco stems briquetting(TSB)was used as fuel during the process of tobacco flue-curing,compared with honeycomb briquette(HB).Three fire furnaces with different heat exchangers using TSB were compared using the tobacco flue-curing.The results showed that the smog temperature of TSB was higher than that of HB,the efficiency of bio-fuel system with TSB was from 43.5%to 54%,while the efficiency of traditional fuel system was 51.5%.And the cost of tobacco flue-curing per hectare with TSB and HB was$750.0 and$1282.5,respectively.It is proved that TSB is an alternative choice using for the industry of tobacco flue-curing,and the improvement in the structure of fire furnace could optimize the process of tobacco flue-curing.

Effects of Different Chemical Fertilizer Reduction Techniques on Flue-cured Tobacco Production

[Objectives]This study was conducted to find out the most suitable special formula fertilizer for flue-cured tobacco production in tobacco-growing areas of Zhaotong City,so as to provide a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.[Methods]Different formulas of special base fertilizer and special topdressing for tobacco were designed by optimizing and adjusting the application amounts and proportions of nitrogen,phosphorus,potassium and medium trace elements in fertilizer formulas,and the formulas of special base fertilizer and special topdressing for flue-cured tobacco production were selected through a field plot experiment.[Results]The combination of special base fertilizer and special topdressing was conducive to the early growth and rapid growth of tobacco plants under the condition of reduced fertilizer application,and the treatment using organic-inorganic compound fertilizer as the special base fertilizer was the most obvious,with an average growth period of two days increased.Compared with conventional fertilization,the yield,output value,average price,proportion of superior tobacco and proportion of medium and superior tobacco increased in the organic-inorganic compound fertilizer treatment,with the yield increasing by 5.96%,the output value increasing by 17.08%,the average price increasing by 10.49%,the proportion of superior tobacco increasing by 4.63%,and the proportion of medium and superior tobacco increasing by 2.44%.It was concluded from indexes including growth period,agronomic traits,disease incidence and economic traits,the fertilization mode of organic-inorganic compound fertilizer with the addition of trace elements(boron,magnesium and zinc)applied as the base fertilizer and nitrogen and potassium topdressing was most efficient and economic.[Conclusions]This study provides a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.

Construction of Anti-breaking Models of the Main Veins of Flue-cured Tobacco Leaves and Principal Component Analysis

[Objective] This study aimed to explore the related mechanisms of the breaking of flue-cured tobacco leaves. [Method] Anti-breaking models of the main veins of flue-cured tobacco leaves were constructed for principal component analysis on the anti-breaking index, leaf traits and cellulose contents. [Result] The results showed that the growth traits had certain relevance with the cellulose contents while the leaf weight assumed a significant negative correlation with the anti-breaking index, indicating that the heavier the leaf weight was, the weaker the anti-breaking capacity of flue-cured tobacco would be; the cross-sectional area of main veins and the cellulose contents had shown a positive correlation with the anti-breaking index, indicating that the thicker the main vein of flue-cured tobacco was, the higher the cellulose contents would be, and the stronger the anti-breaking capacity of flue-cured tobacco leaves would be. [Conclusion] This study provided theoretical basis and reference to improve tobacco production and enhance the quality of flue-cured tobacco.

Effects of Plant Growth Regulator on Absorption,Circulation and Contents of Potassium in Flue-cured Tobacco

[Objective] This study was to investigate the effects of plant growth regulator on accumulation and circulation of potassium in flue-cured tobacco.[Methods] Hydroponics experiment was adopted to study the effects of plant growth regulator（NAA,GA3,BR） on accumulation and circulation of potassium in flue-cured tobacco.[Results] The BR treatment increased the absorption of potassium,calcium and magnesium in flue-cured tobacco,reduced the potassium emission from the root,enhanced the accumulation and contents and promoted the circulation of potassium in the tobacco plants.There was no statistical difference between the NAA and GA3 treatment.And BR treatment was 0.52%,0.30%,0.28% higher than NAA treatment in enhancing potassium content in tobacco plants at 2,7,12 d after topping.In a word,the results showed that BR treatment was the most.[Conclusion] BR treatment could effectively enhance potassium content in tobacco plants after topping.

Effects of Biological Organic Fertilizer on Flue-cured Tobacco Chemical Composition

Through field experiment,special biological fertilizer and cake fertilizer were applied collectively to tobacco,and chemical compositions of Wanxi flue-cured tobacco leaves were researched.The results showed that the increase of biological organic fertilizer would significantly improve soil nutrient supplying capacity.Compared with conventional fertilization,the contents of reducing sugar,total sugar and starch in different parts of tobaccos which were applied with biological organic fertilizer were closer to standards of excellent tobacco.In the treatment,the ratio of reducing sugar and nicotine in tobacco was more suitable in middle and lower parts of the plant and the contents of total N,nicotine and chlorine in tobacco were lowered,improving tobacco quality.

Effects of Vermicompost on Agronomic Characters and Yield and Quality of Flue-cured Tobacco

The effects of vermicompost on the agronomic characters and yield and quality of flue-cured tobacco were investigated. The results showed that, the field growth periods of various treatments were 117-118 d, 1-2 days longer than that of the CK. The numbers of effective leaves of the treatments applied with vermicompost were 0.1-0.3 leaf more than the CK. The highest yield and the highest proportion of high-grade tobacco occurred in treatment 3 as 2 095.5 kg/m^2 and 49%, respectively, which were higher than those in the CK by 6.58 kg and 5.3%. In conclusion, the treatment with the application of vermicompost at 7 500-10 500 kg/hm^2 was the best.

Effects of Different Transplanting and Harvest Dates on Yield and Quality of Flue-cured Tobacco Leaves

In this study,the effects of nine different combinations of transplanting and harvest dates on yield and quality of flue-cured tobacco leaves were investigated.The results showed that different combinations of transplanting and harvest dates had few effects on growth period and agronomic characters of tobacco plants but exerted remarkable effects on economic characters and chemical composition of flue-cured tobacco leaves.With the postponing of transplanting stage,output value of flue-cured tobacco leaves increased.Output value of flue-cured tobacco leaves in C1treatment（normal harvest） was higher than that in C2（harvest 7 d later） and C3（harvest 14 d later） treatments.Different combinations of transplanting and harvest dates had significant effects on chemical composition of flue-cured tobacco leaves,which exhibited no obvious law.Overall,flue-cured tobacco leaves in T3C1treatment（transplanting 14 d earlier,normal harvest） displayed excellent performance compared with other treatments.

Effects of Soil Amendment on Growth,Yield and Output of Flue-cured Tobacco in South Anhui Province

[Objective] The aim of this study was to evaluate the effects of soil amend- ment composed of biochar and inorganic mineral material on growth and develop- ment, yield and output value of flue-cured tobacco in South Anhui Province. [Method] A field plot experiment was conducted. The agronomic traits, yield and output value, as well as appearance quality and flavor of flue-cured tobacco were evaluated. [Re- suit] The soil amendments composed of biochars and inorganic mineral materials could significantly increase plant height, stem diameter, leaf size, yield and output of flue-cured tobacco, as well as proportion of first-grade tobacco leaves at the middle and late growth period. The yield in the X3 treatment group （70% T20 ＋ 30% ZC） was highest, and it was higher than that in the control group by 398 kg/hm2. Com- pared with that in the control group, the output of flue-cured tobacco in the X3 treatment group was increased by 10 290 yuan/hm2. In terms of appearance quality and flavor, the flue-cured tobacco leaves in the soil amendment treatment groups were all better than those in the control group. [Conclusion] The application of soil amendment composed of biochar and inorganic mineral material is an effective mea- sure to improve tobacco-growing soil, promote tobacco growth and development, im- prove tobacco yield and output and improve tobacco leaf quality in South Anhui re- gion.

Effects of Applying Bio-bacterial Fertilizer on Aroma Components of Flue-cured Tobacco

Objective] This research aimed to investigate the effects of bio-bacterial fertilizer on quality of flue-curved tobacco. [Method] The various concentrations of bio-bacterial fertilizer were applied to flue-cured tobacco as leaf fertilizer and base fertilizer respectively. [Result] The effect of bio-bacterial fertilizer on flue-cured tobac-co differed among different treatments. Compared with the control, the bio-bacterial fertilizer significantly affected the quality of flue-cured tobacco. Among al the treat-ments, Treatment 3（leaf fertilizer） showed the best treatment effect, and it significant-ly improved the quality of flue-cured tobacco. [Conclusion] The bio-bacterial fertilizer showed significant improving effect on quality of flue-cured tobacco if spayed as leaf fertilizer.

Investigation and Analysis of Continuous Cropping of Flue-cured Tobacco in Henan Province

The continuous cropping of flue-cured tobacco in the major producing areas of Henan Province by designing questionnaire, fieldwork, enquiry and phone calls, mails, and other forms, the data were obtained then classified and analyzed. The results showed that the main planting areas of flue-cured tobacco were in Nanyang, Xuchang, Luoyang, Sanmenxia, Pingdingshan, and Luohe where were the major producing areas of succession cropping of flue-cured tobacco with percentage of 20%-40% for three years and over three years, and a few places up to 50%. Morbidity was common with wide distribution, and the main diseases were black shank, viral disease, and black rot. It proved that tobacco was not suitable for continuous cropping. Both of tobacco disease and pest rate and mortality significantly increased by more than 40% under continuous cropping for three years and over three years, and the yield and quality of flue-cured tobacco also decreased after continuous cropping. For many places, the tobacco yield started to decrease in the second year of continuous cropping, and after three-year cropping, the yield decreased in the range of 9%-24%. Continuous cropping for a long time would make a serious decline in the quality of tobacco, resulting in non-economic benefits. Therefore, in order to reduce the occurrence of diseases and economic loss in tobacco production, it is recommended to avoid continuous cropping, or to adopt appropriate measures to control tobacco continuous cropping obstacles in the unavoidable case.