| Cucumber Fusarium oxysporium f.s.cucumerinum is a worldwide soilborne disease caused by Fusarium oxysporium.In practice,grafting and chemical methods are often used to prevent and control cucumber Fusarium oxysporium.Allelopathy is a kind of neurodegenerative disease in nature,which is caused by the interaction between plants(including microorganisms).To prevent and control soil-borne diseases induced by allelopathy,different cultivation modes,which include crop rotation,intercropping leisure are generally adopted.In the experiment,celery was chosen for cucumber intercrop.Through both the field and laboratory experiments,allelopathy of cucumber fusarium oxysporium of the two intercropping soil leaching solution,field control effect,influence on crop growth and development,meanwhile revealed the sense on the prevention and control mechanism from the perspective of soil biological characteristics.Allelopathy of cucumber fusarium through intercropping,the effect of allelopathy prevention and control in the field,growth,yield and quality of intercropped crops.The correlation between these indicators provided an effective way and scientific basis for the prevention and control of soil-borne diseases in the field and continuous soil remediation through allelopathy between plants.The main research results follows:(1)At different soil sampling time,the diameter of colony cultured in soil extract solution between the two intercropping systems was the smallest,which was significantly different from that of celery monoculture and cucumber monoculture(P<0.05).With the delay of soil sampling time,the diameter of the colony decreased gradually.Among the three kinds of soil extracts acetone,ethanol and distilled water showed significant difference in colony diameters(P<0.05),among which ethanol was the smallest,followed by acetone and distilled water.The decrease of colony diameter indicated that intercropping had significant allelopathic inhibitory effect on cucumber fusarium wilt,and the allelopathic inhibitory effect was gradually strengthened with the extension of sampling time.(2)Under ifferent soil sampling time,the allelopathic effects of the two intercropping systems were significantly different from those of the single cropping systems of celery and cucumber(P<0.01).With the extension of soil sampling time,the allelopathic effects of the two intercropping systems increased gradually compared with that of the single cropping systems of celery and cucumber.Among them,the allelopathic inhibition effect of the two intercropping was 38.11%?74.95%compared with that of celery monoculture,and 42.15%?75.90%compared with that of cucumber monoculture.(3)The results showed that the cucumber fusarium wilt was reduced by 42.81%and the control effect was 61.43%.The results of pot experiment showed that the disease indexes of the intercropping plants were significantly lower than that of celery monoculture and cucumber monoculture(P<0.05).With the investigation date,the disease indexes showed a gradually increasing trend,and the disease indexes tended to be stable 13 days after inoculation.Compared with the control effect of celery monoculture,the control effect of the two treatments reached 57.03%?63.54%,and that of cucumber monoculture reached 66.95%?72.15%.(4)Intercropping promoted the production and development of intercropping crops,increased the yield and improved the quality.Meanwhile,intercropping reduced the first female flower section and increased the number of female flowers with 30 sections.Besides,the contents of soluble sugar,VC,soluble solid and soluble protein were significantly increased by 23.98%,18.05%,19.19%and 10.86%respectively.Moreover,the single plant weight of cucumber was significantly increased by 16.25%.(5)Intercropping of the Observed species index,Shannon index and Chao1 index all reached the maximum value,which changed the composition and distribution of soil bacterial community and improved the Alpha diversity index of bacteria.The results of Beta diversity showed that the environmental community species in the intercropping soil were different from cucumber monoculture and celery monoculture.A total of 45 phyla were detected by 16S rDNA,among which proteobacteria were the dominant group,followed by acidobacteria,actinomycetes,chlorobacteria and blastomonas.The results showed that the combination of the two treatments had the highest percentage of soil bacterial community abundance(87.33%),followed by cucumber monoculture(86.44%)and celery monoculture(85.70%).Among the top 10 species of bacteria in phylum classification level,the composition of soil bacterial community in intercropping was the highest,accounting for 98.63%,which was 1.69%higher than that in cucumber monoculture and 1.22%higher than that in celery monoculture.At the phylum classification level,intercropping had the highest distribution ratio,darkest color and higher species richness,followed by monoculture of celery and cucumber.The results showed that the bacterial species abundance of cucumber monoculture and celery monoculture soil were the same,and the community structure was similar.(6)Through intercropping,the Observed species index,Shannon index,Chao 1 index and Simpson index showed no significant difference from the control group(p>0.05).Five fungal phylum were detected by ITS,ascomycota,zygomycota and basidiomycota were the three main phylum.Among them,the intercropping soil fungi had the most abundant species,accounting for the highest proportion(95.50%),followed by cucumber monoculture and celery monoculture(94.23%and 93.17%respectively),and the unclassified or undifferentiated phylum accounted for 5.10%.At the phylum classification level,the monoculture of celery had the highest expected value,the deepest color and the highest species richness,followed by monoculture of cucumber and intercropping of cucumber and parsley.The results of cluster analysis showed that the species abundance of intercropping and monoculture were the same,and the community structure was similar.(7)With the delay of sampling time,the activities of hydrolases and Redox enzymes increased gradually through intercropping.Among them,the overall change trend of urease,sucrase,amylase,catalase,polyphenol oxidase and peroxidase was cucumber and celery intercropping>celery monoculture>cucumber monoculture,while the protease was celery monoculture>cucumber and celery intercropping>cucumber monoculture.(8)There was a certain correlation existing between the allelopathy prevention and control effect of cucumber fusarium wilt and soil microorganism,also between soil microorganism and soil enzyme and crop growth.The disease condition index was significantly positively correlated with the bacterial proteobacteria,and the correlation coefficient was 0.919,which was significantly negatively correlated with acidobacteria,chloroform and blastomonas.There was a significant positive correlation between the two species,with the correlation coefficients of 0.852,0.883 and 0.866 respectively.The proteobacteria were positively correlated with urease and catalase,and the correlation coefficients were 0.990 and 0.999.Besides urease and catalase,five enzyme activity indicators were positively correlated with the vegetative growth of cucumber(0.911?0.997).Urease and catalase were positively correlated with cucumber yield,and the correlation coefficient was 0.626?0.988.The first five species of bacteria and the first five species of fungi were positively correlated with cucumber nutritional quality,with correlation coefficients of 0.387?0.999 and 0.626?0.988. |
PDF Full Text Request