Reguating Effect Of Sodium Nitroprusside On Physiological Characteristics In Maturation Process And Holding Ability Of Flue-cured Tobacco Leaves

At present,the field maturity duration of Flue-cured Tobacco planted in most areas of China is short,and the holding ability is generally not high,which seriously affects the improvement of the quality of flue-cured tobacco,causes the economic losses of tobacco farmers,and the demand for high-quality raw materials in the cigarette industry can not be met.We used the flue-cured tobacco variety K326 as the test material to explore the effect of no on the holding ability of Flue-cured Tobacco by spraying exogenous active substance SNP(sodium nitroprusside)on the leaf surface as the release agent of signal substance NO(nitric oxide),and set 100 μmol/L、300 μ mol/L、500 μ Mol/L at three different concentrations,they are recorded as processing groups SNP1,SNP2 and SNP3,with clear water as the control.Spraying was carried out on the lower,middle and upper leaves for a fixed period of time,twice in each period,with an interval of one day.Through the comprehensive analysis of physiological indexes such as nitric oxide content,1-aminocyclopropane-l-carboxylic acid(ACC)content,protein content,SPAD value,cell membrane stability index(MSI)value,ripening tolerance index ISPAD,chemical components of flue-cured tobacco leaves and economic properties of tobacco leaves per unit area,the regulatory effect and mechanism of NO on the holding ability of flue-cured tobacco were understood.The main test results are as follows:1.Effects of sodium nitroprusside on physiological indexes related to ripening tolerance of flue-cured tobacco leavesExogenous sodium nitroprusside treatment can significantly reduce the ACC content of tobacco leaves,and gradually decrease with the increase of spraying concentration,significantly improve the MSI value,soluble protein content and SPAD value of tobacco leaves,maintain relatively high cell membrane stability and reduce the degradation rate of soluble protein and chlorophyll in the aging process,so as to delay the aging of tobacco leaves,And it has a certain concentration effect.With the increase of spraying concentration,the delay effect increases gradually.2.Effects of sodium nitroprusside on routine chemical components of flue-cured tobacco leavesThe chemical composition of flue-cured tobacco leaves can more clearly evaluate the industrial availability of tobacco leaves.By measuring the contents of several representative groups of chemical components in flue-cured tobacco leaves after different treatments,it is found that after the routine chemical composition analysis of flue-cured tobacco leaves by spraying different concentrations of exogenous SNP on the leaf surface,it is found that compared with the control group,Each treatment group can effectively reduce the total nitrogen content and nicotine content,and increase the total sugar content,reducing sugar content and sugar alkali ratio.The performance of tobacco leaves in different parts is relatively uniform and the difference is significant,which can effectively improve the quality of flue-cured tobacco leaves.The relative effect of SNP2 in the treatment group is better.3.Effect of sodium nitroprusside on ripening tolerance index ISPAD of flue-cured tobacco leavesBased on the previous research results on the ripening tolerance of flue-cured tobacco leaves[1],combined with the measurement indexes of this experiment,the ripening tolerance index(Ⅰ),i.e.ISPAD,calculated according to the relative change rate of SPAD value,is proposed.The larger the ISPAD value,the slower the senescence of tobacco leaves.Considering the actual harvest situation,the I value should be within an appropriate range.The results showed that spraying different concentrations of SNP on the leaves could effectively improve the maturity tolerance index of tobacco leaves,and increased with the increase of concentration.There was no significant difference between SNP2 and SNP3 in the treatment group.4.Effects of sodium nitroprusside on economic characters of flue-cured tobacco leavesUnder the same conditions,the method of spraying different concentrations of SNP on the leaf can significantly improve the yield,output value and the proportion of superior tobacco per unit area.Specifically,the yield per unit area is the most in treatment group SNP3,and the output value per unit area and the proportion of superior tobacco are the most in treatment group SNP2.The concentration of SNP2 is recommended.In conclusion,spraying different concentrations of SNP can effectively increase the content of NO in leaves and significantly reduce the content of ACC,indicating that there is also a hormone regulation pathway in delaying tobacco senescence;The relatively high levels of dynamic SPAD value,MSI value,soluble protein content and ISPAD value also directly showed that reducing the ethylene biosynthesis of flue-cured tobacco leaves could delay the senescence of flue-cured tobacco leaves by slowing down the degradation of chlorophyll,maintaining the stability of protein content and improving the stability of cell membrane;To a certain extent,it can also improve the content of flue-cured tobacco leaves;Combined with the performance of economic characters,although they can effectively improve economic benefits,they are not in positive proportion to the spraying concentration.Considering the cost under different conditions,it is recommended to spray SNP2(300 μ mol/L)during field planting concentration.