Study On Compouning Plant Cold-Resistant Agent And Its Effect On Cold Tolerance In Crops Seedling

Low temperature of the plant geographic distribution and has an important influence on growth and development.Statistics show that the annual damage of agricultural crops caused by the global low temperature of thousands of yuan.In recent years,the extreme gas frequent economic losses will increase.The planting of spring corn is Geographically widespread in our country,early spring cold damage(above 0 ?low temperature)is one of the major natural disasters seriously for corn producing,which has effects on maize germination and seedling growth,it also has become one of the important factors of corn yield.So the research that Cold agent improve cold tolerance of maize seedlings and other crops both have important theoretical and practical significance for for crops in the spring regreening period "Unusually cold spell in early spring" caused by chilling injury.In this paper,we studied the effect on corn seedling under low temperature(5?)stress of eight kinds of exogenous substances(SA,FA,ASA,S3307,LBG,KH2PO4,Pine Needle liquid extraction,Seabuckthorn liquid extraction)and select in the first three exogenous substances.Two kinds of mixed liquid of plant cold hardiness of different components in preparation,Pine Needle liquid extraction as the base fluid,with KH2PO4 and ASA as the basic material.In Yuyu 22 corn as the material,the formula was optimized by orthogonal test,screening out the optimal concentration ratio of maize seedlings to improve cold hardiness.To choose the optimization of compound plant cold liquid pre-spraying to three maize varieties(Yuyu22,Jinsui1203,Yuhuizao Tiannian)on parallel test,physiological indicators were measured after cold stress under 5?,and the license role of optimized cold agent was verified furtherly.In order to further expand the scope to optimized cold agent,the Brassica campetris(rape)‘Longyou 9'seedling as experimental material,physiological indicators were measured after the stress-related low 0 ?temperature.The main findings are as follows:1.we used eight kinds of exogenou substances(SA,FA,ASA,S3307,LBG,KH2PO4,Pine Needle liquid extraction,Seabuckthorn liquid extraction)pretreatment of corn seedling,the results show that all can improve the corn seedling cold hardiness.The processing to improve the corn seedling of the same exogenous substances concentrations of hardiness difference.Between physiological effects of exogenous substances vary,hardiness effect is the best for S3307,followed by the SA and FA.Composite antifreeze index,chlorophyll content,SOD activity and MDA content of the four physiological indexes,concluded that hardiness pecking order and the best concentration of 3307(0.06g/L)>SA(0.05g/L)>FA(0.6g/L)>LBG(1.2g/L)>KH2PO4(3g/L)>ASA(3g/L)>Pine Needle liquid extraction(0.005g/m L)>Seabuckthorn liquid extraction(0.005 g/m L).2.The A,B two different components Cold agent were further optimized by orthogonal.Yuyu22 corn was used to selecte combinations and the optimal concentration the combination of ratio for maize seedlings to improve cold tolerance,moisture content,conductivity,chlorophyll content three physiological indicators were determined,two optimal concentration ratio formula of cold better A7 and B8 were screened out combining with chilling injury index,the formula as follows:A7:G(1.2g/L),S3007(0.06g/L),FA(0.6g/L),KH2PO(3g/L)and ASA(3g/L),extract 0.005g/ml with Pine Needle liquid extraction,finally fill the Pine Needle liquid extraction to 1000 m L.B8:BG(1.2g/L),S3007(0.06g/L),SA(0.08g/L),KH2PO4(3g/L)and ASA(3g/L),extract 0.005g/ml with Pine Needle liquid extraction,finally fill the Pine Needle liquid extraction to 1000 m L.3.By pre-spraying A7(N1)and B8(N2)two optimization Cold agents for three varieties of corn Yuyu22,Jinsui1203,Yuhuizaotiannian,and cold stress treatment under 5 ?conditions,six physiological and biochemical factors seedling REC,MDA,SOD,proline,soluble sugar,soluble protein were measured respectively before treatment,cold stress for three days,five days,recovery growth after three days.The effect of cold tolerance of A7(N1)and B8(N2)to improve of maize seedlings were further validated.The results showed that ompared with the control N1 and N2 were able to significantly improve the content of soluble sugar,soluble protein content,SOD activity,proline content,could significantly reduce the level of membrane damage and MDA content among three varieties;By comparing the cold effect of N1 and N2,only Yuyu22,the difference of MDA content,proline content and soluble sugar content were not significant,the rest indicators reflected that the mitigation of N2 for corn seedling chilling injury was better than N1.In order to expand the application scope for crop of Cold agent furtherly,the Brassica campetris(rape)‘Longyou 9'seedling as experimental material,pre-spraying the preferred N2 cold agent,then 0? cold stress treatment,series of physiological and biochemical factors soluble sugar content,soluble protein content,SOD activity,proline content,chlorophyll content,conductivity,MDA content were determined,the results show that N2 still has synergism on cold resistance of Brassica campetris(rape)‘Longyou 9' seedling.