| In order to provide the theory basis of se-rich tobacco leaves production,a field experiment was conducted to study the effects of selenium level and applying time on the growth(the growth stages,economical character,root activity,key enzyme activity,MDA content,chlorophyll content,Photosynthetic characteristic) and se content of flue-cured tabocco.Through the research of K326 for all treatments,The results are as follows:1.The effects of spraying selenium on the growth and economical characters of flue-cured tobacco:treatment10mg/l Na2SeO3 and treatment 30mg/l Na2SeO3 had a promoting effect on the growth of tobacco plant,There had premature flower of tobacco plant under treatment 50mg/l Na2SeO3.Treatment 10mg/l Na2SeO3 and treatment 30mg/l Na2SeO3 had a promoting effect on the tobacco leaves,The plant height,leaf area and stem girth of treatment10mg/l Na2SeO3 and treatment 30mg/l Na2SeO3 were higher than that of contrast,but which of treatment 50mg/l Na2SeO3 were lower than that of contrast,Se had a promoting effect on the growth of tobacco plant.The earlier the selenium spraying,the more obvious this function was.2.The effects of spraying selenium on the root activity,key enzyme activity and MDA content of flue-cured tobacco:In early growth period,the root activity and MDA content of treatment 10mg/l Na2SeO3 and treatment 30mg/l Na2SeO3 were higher significantly than that of contrast,but which of treatment 50mg/l Na2SeO3 were lower than that of contrast,in the vigorous stage,the root activity of all treatments increased with the rising of se level.In early growth period,the CAT and POD activities of treatment 10mg/l Na2SeO3 and treatment 30mg/l Na2SeO3 were higher significantly than that of contrast,but the CAT and POD activities of treatment 50mg/l Na2SeO3 were lower than that of contrast,in the mid and later periods,the CAT activity of treatment 10mg/l Na2SeO3 and treatment 30mg/l Na2SeO3 were higher than that of contrast,There were no significantly differences between treatment 50mg/l Na2SeO3 and contrast,the GSH-Px activity of all treatments increased with the rising of se level.3.The effects of spraying selenium on the chlorophyll content,Photosynthetic and characteristic of flue-cured tobacco:There were different effects in different spraying time and different selenium levels,The effect of spraying selenium in early growth period were better than that in vigorous stage,the chlorophyll content of all treatments increased with the rising of se level,but decreased under treament 50mg/l Na2SeO3,The photo-synthesis rate,stomatal conductance,transpiration rate increased with the rising of se level.4.The effects of spraying selenium on the se content and Se-fertilizer utilization rate of flue-cured tobacco:The se content of lower leaves were higher than that of middle leaves,which of middle leaves higher than that of upper leaves,se content of flue-cured tobacco leaves increased with the rising of se level,The later the selenium sprayed,the higher the se content of flue-cured tobacco had,Se-fertilizer utilization rate of flue-cured tobacco were 1.9%～3.6%,Se-fertilizer utilization rate of spraying were 6～10 times than that of applying on soil.The Se conent in different organs of flue-cured tobacco were:leaf＞stem＞root,Se conent of leaf,stem and root increased with the rising of se level,the correlation coefficient of Se conent and Se application rates were greater than 0.95,spraying selenium had a promoting effect on Se conent in different organs for flue-cured tobacco significantly. |
