Li Zhanghai

Preliminary Study on Critical Level of Available Mo in Flue-cured Tobacco Planting Soil

For applying Mo fertilizer in a reasonable and effective way,the effects of molybdenum nutrient on various trait indexes of flue-cured tobacco and critical value of available Mo in soil were studied by field trial and pot experiment.The results showed that tobacco leaf yield was increased and leaf quality was improved by Mo applying.The pot experiment indicated that the critical values of available Mo in soil were 0.30 and 0.10 mg/kg based on yield traits and oil characters of tobacco leaf,respectively.The field trial demonstrated that the critical value of available Mo in soil was 0.15 mg/kg based on yield traits and about 0.02 mg/kg when the proportions of high grade and variegated leaves were concerned.

Effects of Molybdenum on Enzymatic Browning Reaction-related Indexes During Flue-cured Tobacco Curing

The effects of molybdenum application on the AsA content and PPO activity in tobacco leaf during early curing stage and the grade of cured leaf were investigated with field experiments,tobacco of cv.K326,Yunyan85,CB-1 and Honghuadajinyuan(Hongda),was sprayed with molybdenum fertilizer on leaf surfaces.The results showed that for soil deficient of Mo(0.03 mg/kg available molybdenum),the AsA contents in ripe leaves of K326 and Yunyan 85 increased significantly by foliar spray of molybdenum,and the AsA content in tobacco leaves of the 4 cultivars was generally higher than that in CK at early curing stage(0 to 72 h).Foliar spray of molybdenum evidently reduced PPO activity in leaves of K326,Hongda and CB-1,PPO activity in leaves of the 4 cultivars was basically lower than that of CK at early curing stage,especially in 0 to 48 h.Molybdenum application significantly increased the percentage of high and middle grade leaves and decreased the percentage of variegated leaves.

Effects of NAA Application After Topping on Accumulation and Distribution of Potassium in Flue-cured Tobacco

The effects of NAA blotter insertion on accumulation and distribution of potassium in flue-cured tobacco were studied with pot culture.The results showed that the accumulation amount of potassium in tobacco plant treated with A(0.22%NAA) and B(0.22%NAA+synergist) averaged 1.06g and 1.42g per plant higher than that in CK,potassium content in upper leaves increased by 0.39 and 0.06 percentage points and in cutters by 0.32 and 1.17 percentage points,respectively.Comparing with CK,the accumulation amount of potassium in A and B treated tobacco leaves increased averagely by 0.49g and 0.98g per plant,the potassium distribution proportion in tobacco leaf increased by 0.25 and 4.57 percentage points,respectively.NAA could improve the potassium accumulation in tobacco plants and change the potassium distribution among different tobacco apparatus.The potassium distribution proportion and content in tobacco leaf were increased by NAA application.

Effect of Maturity at Harvest on Aroma Components in Flue-cured Tobacco cv.CB-1 Grown in Sanming

In order to study the effect of maturity at harvest on aroma components in flue-cured tobacco cv.CB-1 grown in Sanming,an experiment was conducted with upper and middle leaves of CB-1.The results showed that: with the increase of maturity,the contents of total aroma components and neutral portion in cured leaves increased first and then decreased,the content of acidic portion tended to decrease,while the content of alkaline portion tended to rise.Considering the dynamic of main components,the preliminary conclusion was that: for cv.CB-1 in Sanming,upper and middle leaves should be harvested slightly earlier than usual,i.e.middle leaves be harvested when leaf surface was yellowish green,2/3 of midrib length became white and veins started to turn white;upper leaves be harvested when leaf surface was greenish yellow,the base of midrib became white and more than 2/3 of veins turned white.

Changes of Polyphenols and Other Compounds,and Relative Enzyme Activity in Tobacco Processing

In order to investigate the change of polyphenols and other compounds, and relative enzyme activity in tobacco leaf during tobacco processing,the changes of polyphenols,starch,total sugar,reducing sugar,total nicontine,total nitrogen and the activities of polyphenol oxidase(PPO) and total amylases in tobacco before and after 6 key process steps were tested and analyzed.The results showed that: the contents of polyphenols,starch,total sugar,total nicotine and total nitrogen decreased through the 6 key process steps;and activities of PPO and amylase reduced persistently after first conditioning and lamina storing;reducing sugar decreased in all the key process steps except for lamina storing.