Effects Of Brassinolide And Auxins On Growth And Leave Quality Of Flue-cured Tobacco After Topping

A field experiment was conducted in Jiyuan Tobacco Area of Henan Province,the experiment included 6 treatments,which were spraying water?T1?,spraying 10 mg.kg^-1 BR?T2?,spraying 10 mg.kg^-1 IAA?T3?,spraying 20 mg.kg^-1 IAA?T4?,spraying 10 mg.kg^-1 IAA and 10 mg.kg^-1 BR?T5?,spraying 20 mg.kg^-1 IAA and 10 mg.kg^-1 BR?T6?,this paper studied the effect of spraying brassinosteroid and auxin on field growth,plastid pigment and its degradation products,physical properties,Carbon and nitrogen metabolism and tobacco quality in flue-cured tobacco after topping through the field experiment,the main conclusions are as follows:1.Spaying brassinosteroid and auxin after topping could promote the upper leave to expansion,promote root to growth,improve the production of upper leave,and when applying both at the same time,the effection is better.2.Spraying brassinosteroid and auxin after topping could improve the content of the middle and upper leaves of flue-cured tobacco chromoplast pigment and its degradation products in varing degrees,but had no significant effect on the lower leaves.When brassinosteroid is used in conjunction with auxin,the effect was more significant on the middle and upper leaves.The content of chlorophyll,carotenoid,neophytadiene,carotenoid degradation products and total chromoplast pigment degradation products were the highest in the middle and upper leaves of treatment T6(IAA 20 mg.kg^-1 + BR 10 mg.kg^-1);the ratio of carotenoid and chlorophyll were 7.16 and 7.63 respectively.3.Spraying brassinosteroid and auxin after topping could improve the leaf length,leaf width,leaf weight,filling capability and tensile strength,reduce the stem ratio of the middle and upper leaves of flue-cured tobacco,but have a little effect on the physical properties of the lower leaves,the treatment T6(IAA 20 mg.kg^-1 + BR 10 mg.kg^-1)has the most obvious effection.4.In addition to contrast treatment,other treatments of the nitrate reductase and glutamine synthetase activity were shown as after rising first down,the invertase and amylase activity were shown as after falling slightly rising,this suggests that Spaying brassinosteroid and auxin after topping could enhance the strength of the carbon and nitrogen metabolism of tobacco plant,but to a certain extent delayed the tobacco maturity and fall time of yellow,extended the growth period.5.Spaying brassinosteroid and auxin after topping could effectively improve the content of potassium,potassium-chlorine ratio and organic potassium index,and reduce the nicotine and chlorine content of middle and upper leaves,the effection on upper leaves is most obvious,and when applying both at the same time,the effection is better.the effection which promote the growth of tobacco plant and improve the quality of leaves is best of the treatment T6(IAA 20 mg.kg^-1 + BR 10 mg.kg^-1),relative to the treatment T1,the treatment T6 can make the potassium content,potassium-chloride ratio and organic potassium index increased by 40.9%,68.5% and 0.524 respectively,the chlorine content and nicotine reduced 16.2% and 16.3% respectively of the upper leaves.