稻秸蓝藻混合厌氧发酵沼液及其化学物质对尖孢镰刀菌西瓜专化型生长的影响

Abstract

研究稻秸与蓝藻(1∶1)混合厌氧发酵的沼液及其微量化学成分对尖孢镰刀菌西瓜专化型(<em>Fusaruim oxysporum </em>f. sp. <em>niveum</em>,FON)的孢子萌发、孢子数量、菌丝生长的影响。结果表明:40%浓度的发酵沼液即可100%抑制孢子萌发,20%浓度的沼液即可达到98.74%的抑制菌体产生孢子,100%浓度的沼液显著抑制气生菌丝的生长;进一步GC-MS分析发现沼液有机物成分中烷类较多,存在微量的四氯化碳(CCl₄)、六氯乙烷(C₂Cl₆)、1,1-二乙氧基乙烷(CH₃CH(OCH₂CH₃)₂)3种化学物质;三者都具有显著的抑菌效果,且随浓度的增加而增大,尤其CH₃CH(OCH₂CH₃)₂的抑菌效果最好;0.75%浓度的3种化学物质对孢子萌发的抑制率即可达到100%;在培养基中分别加入CCl₄、C₂Cl₆、CH₃CH(OCH₂CH₃)₂的浓度为1.00%时,镰刀菌的产孢数量分别降低了5.67%、18.05%、8.72%;培养4d,三者对尖孢镰刀菌西瓜专化型气生菌丝生长的抑制效果均达到90.40%,效果显著。研究表明沼液中确实存在对病原微生物具有明显抑制作用的多种有效的化学成分,可作为防治病原菌的首选药剂。;Fusarium wilt of watermelon caused by <em>Fusarium oxysporum</em> f. sp. <em>niveum</em> is world wide in occurrence, which belongs to Fungal soil-borne diseases. Spore germination, mycelial growth and sporulation are important stages of disease spread, the medicament which can block any growth stage of pathogenic bacteria can control the disease. The effect of microchemical substances in anaerobic fermented liquid from rice straw and cyanobacteria(1∶1)on <em>Fusaruim oxysporum</em> f. sp. <em>niveum</em> growth was investigated. It included spore germination, spore number, and mycelial growth. The results showed that spore germination number reduced 6.25%、37.5%、77.5% respectively at the 5%, 10% and 20% concentration groups, especially inhibited by 100% at 40% concentration of biogas slurry. The spore production could be inhibited by 98.74% at 20% concentration of biogas slurry. The aerial mycelial growth could be almost inhibited at 100% concentration of biogas slurry. Further analysis by gas chromatograph-mass spectrometer found that there are many kinds of alkyl substances in the organic component from biogas liquid. Three microchemical substances, CCl₄, C₂Cl₆, CH₃CH(OCH₂CH₃)₂ measured in biogas liquid by GC-MS analysis had distinct inhibition effects. The inhibition effects increased with their concentrations, especially CH₃CH(OCH₂CH₃)₂. The spore germination number reduced 20.22%、28.84%、40.82% respectively when CCl₄, C₂Cl₆ and CH₃CH(OCH₂CH₃)₂ were added in culture medium at the 0.1% concentration; and the inhibition rate respectively increased to 81.27%、79.78%、86.52% at 0.5% concentration. The spore germination were inhibited by 100% at the 0.75% concentration of three chemicals; The numbers of producing-spore reduced 5.67%、18.05%、8.72% respectively at the 1% concentration of three chemicals; The inhibition rate was 80.91%, 75.59% and 99.22% respectively at 3% concentration of three chemicals. The restraint effects of three chemicals were very notable on the aerial mycelial growth with training four days, especially CH₃CH(OCH₂CH₃)₂ at 0.10%-1.00% concentration and CCl₄ or C₂Cl₆ at the concentration more than 0.25%. The inhibiting rate would get to 90.4% when three chemicals at 1.00% concentration were added in the medium. The tolerance of <em>Fusarium oxysporum</em> f. sp. <em>niveum</em> on three microchemical substances increased with prolonging culture time. The aerial mycelium in every tested group grown at some extent. The restraint rate of three chemicals was 77.96% on the aerial mycelial growth with training seven days, especially 1,1-CH₃CH(OCH₂CH₃)₂ getting to 87.22%. The restraint effects increased with the concentration in the range of 0.10% to 1.00%. But the inhibiting rate declined slightly comparing with four days at same period. The experiment results showed that three chemicals remarkably restrained the growth of prophase aerial mycelial. Multi-specific ingredients were included in the biogas liquid to inhibit the pathogenic microbe. Biogas slurry can be used to control the growth of pathogenic microbes as one of the preferred agents, which will resolve the long-troubled problem about the disease and provide reference to prevent fusarium wilt of watermelon for the future study.