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Mechanisms Of KP On The Physical And Chemical Characteristics And Root Bleeding Sap Of Maize Leaves And Stalks

Posted on:2019-05-30Degree:MasterType:Thesis
Country:ChinaCandidate:H C FanFull Text:PDF
GTID:2393330545956221Subject:Crop Cultivation and Farming System
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Maize is the largest grain crops in Heilongjiang Province.In recent years,with the continuous increase in planting density,lodging has become one of the important factors affecting production.The purpose of this study is to explore the effects of KP(a kind of plantgrowth regulator made with DCPTA and ETH by our lab)on stalks,roots and photosynthetic properties of maize and its relationship to lodging rates,and to define the mechanics of KP regulation of the stalk and root lodging resistance.The mechanism and the feasibility of increasing production of maize provide a theoretical basis for the rational use of chemical regulators in production.In this experiment,Dongnong 253 was used as the test material.DTB and KP were sprayed at the 6-leaf stage of maize,and the control was water(CK).The sampling analysis was carried out at the jointing stage,anthesis silking stage,earlyfilling stage,milk stage andmaturing stage,respectively.The tests were carried out on the lodging resistance of stalk and root,the physicochemical characteristics of stalk,the characteristics ofroot bleeding sap,photosynthetic performance of leaves,grain filling and yield,etc.The results of the study show that:(1)The plant height,ear height,ear height coefficient,basal internode length,center of gravity height and lodging rate were decreased with the application of KP,while the stem diameter,stem diameter index,puncture strength,bending strength,the number,depth,diameter and dry weight of aerial root in the soil were increased.The correlation analysis showed that the maize stem and root lodging resistance characteristics were closely related with the actual lodging rate.The KP increased the maize stem and root lodging resistance properties,reduced the field lodging rate.The effect of KP on strong stalks and rootsof maize is better than DTB.(2)Sprayed KP could significantly improve the activity of 4-coumarate: CoA ligase(4CL)and cinnamyl alcohol dehydrogenase(CAD)in maize stem,the content of cellulose,hemicellulose and lignin,bending resistance,and lodging resistance index also improved significantly,the actual lodging rate decreased significantly.Correlation analysis showed that the lodging resistance index was extremely positively correlated with the content of lignin and hemicellulose(correlation coefficients were 0.67 and 0.64 respectively),the bending resistance was extremely positively correlated with the content of cellulose(correlation coefficient was 0.89),the content of lignin was extremely positively correlated with the activity of CAD(correlation coefficient is 0.89)and positively correlated with the activity of 4CL(correlation coefficient was 0.51),and phenylalanine transaminase(PAL)and tyrosine ammonia lyase(TAL)activity showed no significant correlation.Spraying KP at the 6-leaf stage can improve the activity of key enzymes in stem lignin(especially the activities of CAD and 4CL),and improved the fiber quality of stem fiber,which significantly enhanced the lodging resistance of spring maize stems.(3)The total volume of roots bleeding sap,especially in the later growth stages,and the mineral nutrients and amino acid especially Ser in the root bleeding sap were increased by the treatment of KP.The content of IAA,CTK and ABA were also promoted in every stage.Whereas the content of GA was significantly improved at the milk stage,and lower than that of control at jointing,anthesis silking and filling stages,which was significantly increased later.Chemical regulators had different effects on the ratio of endogenous hormones and change the balance of hormones.In addition,the use of chemical regulators increased the grain number per row and 100-grain weight,and finally improved the yield.The correlation analysis showed that The root bleeding sap and its components were closely related to the yield,indicating that the Mixed compound of DCPTA and ETH had the effects of regulating root bleeding sap,mineral elements and endogenous hormones,which playing an important role in promoting the growth and development of shoots.(4)KP treatment also significantly increased leaf chlorophyll content,net photosynthetic rate,and activity of PEP carboxylase and RuBP carboxylase.Correlation analysis showed that leaf SPAD,PEPc,RuBPc,and Pn were significantly positively correlated with yield,and there are differences in the correlation coefficient at different fertility stages.(5)The rate of grain filling was closely related to the formation of yield.KP increased the grain filling rate during the grain filling stage,and also significantly increased grain number and grain weight per row.However,it had no significant effect on the number of effective panicles and the number of rows per ear.The maximum theory yield of the KP treatment was 11980.73 kg/ha.
Keywords/Search Tags:Maize, Chemical regulator, Roots bleeding sap, Physical and chemical Characteristics, Lodging resistance
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