Synthesis,characterization Of Diallyl Macromolecular Quaternary Ammonium Salt And Its Application In Inhibiting Banana Fusarium Wilt

Banana Fusarium wilt,as a plant disease caused by fungi,is difficult to control,because its fungal spores can survive in the soil.To control this disease,both biological methods and small-molecular chemicals have been developed.However,the cost of biological control is usually too high for agricultural application.As for the small-molecular chemicals,they are easy to lose,which results in only short-time function.Besides,the large amount of use of these chemicalshas also led to environmental pollution.The macromolecular quaternary ammonium salts(QASs)have the advantages of high charge density and structural diversity,and broad-spectrum fungicidal properties and good water solubility as well.Published researches on macromolecular QAS shave mainly focused on the side-chain structured polymers.In this thesis,a series of N,N-diallyl main-chain macromolecular quaternary ammonium salts have been synthesized with stronger bacteriostatic activity,including:polymethylbutadiene-propyl ammonium chloride(PMBDAAC),polymethylbenzyl diallyl ammonium chloride(PBMDAAC),polydimethyl diallyl ammonium chloride(PDMDAAC).The effects of the main-chain macromolecular QASs with different structure on the inhibitory properties of bacteria,Candida albicans and Fusarium oxysporum f.sp.cubense(Foc4)and their environmental biotoxicity have been investigated.On this basis,the adsorption and migration behaviors of PDMDAAC with low toxicity and high efficiency to Foc4 in soil and their inhibition characteristics to Foc4 in soil were studied.The main work of this paper consists of two parts:1.Three types of N,N-diallyl macromolecular QASs were synthesized by radical polymerization(PMBDAAC,PBMDAAC,PDMDAAC)and characterized.2.Three kinds of main chain macromolecular QASs behaved as cationic surfactants,forming micelles in water and had good dispersion.Besides inhibiting bacteria and conventional pathogenic fungi,the spores and hyphae of Foc4 could be effectively inhibited.The inhibition effect did not change much with the increasement of molecular weight.The inhibition effect of PBMDAAC on spores were comparable to that of benzalkonium chloride(BC),a commercial small-molecular QAS.For insects such as silkworm,it is low or even nontoxic.For mammals such as mice,it is low or even nontoxic,and it is toxic to aquaticorganisms such as zebrafish.The environmental toxicity of three types of main-chain macromolecular QASs is much lower than that of BC.Targeting Foc4 in soil,the application of PBMDAAC showed that the adsorption of PBMDAAC in soil was stronger than that of BC,while the mobility with water in soil is weaker than that of BC.These characteristics could facilitate a betteri nhibition against Foc4 spores in soil.