| Fusarium disease is a worldwide rhizosphere soil-borne disease, the disease incidence increased significantly, which threaten and impeded seriously the production of cucumber. Using allelopathy to prevent soil-borne diseases is a method in today’s plant protection.The growth rate method and the column chromatography were used to study the allelopathy of the root、 the rhizosperic soil and the volatile of parsley on Fusarium oxysporium f.sp.cucumeris, and further research the allelopathy mechanism on Fusarium oxysporium f.sp.cucumeris, and preliminary allelochemicals separation with the strongest allelopathic extracts, and then the allelochemicals were analysed by the GC/MS to determine the composition which provided scientic and theoretical foundation for preventing fusarium disease by using allelopathy and developing antibacterial agent of plant source. The main results were as follows:-1. The extracts of the root and the rhizosperic soil of parsley had allelopathic effect on Fusarium oxysporium f.sp.cucumeris, and which had obviously inhibition in certain range of concentration, The higher the concentration, the stronger the effect of allelopathy. The highest inhibition rates of the acetone extracts of the root and the rhizosperic soil of parsley were33.97%and39.26%, the highest inhibition rates of the ethanol extracts were42.31%and94.37%, the highest inhibition rates of the aqueous extracts were38.07%and21.27%. The ethanol extracts showed the strongest inhibitory effeet on Fusarium oxysporium f.sp.cucumeris.2. After treat with the extracts of the root and the rhizosperic soil of parsley, the intracellular protective enzyme (SOD, CAT) activity decreased compared with the control, and the cell wall-degrading enzymes (cellulase,pectinase,β-glucosidase) was lower than the control, and the MDA content and soluble protein content increased compared with the control.3. The intracellular protective enzyme (SOD, POD, CAT), the PPO, PAL and chitinase activity of the cucumber seedlings were higher than the control after treat with the extracts of the root and the rhizosperic soil of parsley, and the MDA content, soluble protein and H2O2content were lower than the control.4. The main allelochemicals of the best ablelopathy fraction of the acetone extract in the root and the rhizosperic soil of parsley after secondary separation were2-Propenoic acid, pentadecyl ester; the main allelochemicals of the best allelopathy fraction of the ethanol extract in the root and the rhizosperic soil of parsley after secondary separation were4-Dimethylamino-2-methyl-l-phenyl-butan-2-ol8-Octadecenoic acid, methyl ester、Hexadecanoic acid, methyl ester、Octadecadienoic acid, methyl ester; the main allelochemicals of the best allelopathy fraction of the aqueous extract in the root and the rhizosperic soil of parsley after secondary separation were1-Hexadecanamine, N,N-dimethyl-、 Pentadecanoic acid,14-methyl-, methyl ester、 Cyclotrisiloxane, hexamethyl-、9-Octadecenoic acid, methyl ester,(E)-Methyl ricinoleate、Heptadecanoic acid,16-methyl-, methyl ester.5. The parsley volatile did have allelopathic effect on Fusarium oxysporium f.sp. cucumeris, and the effect increased with increasing concentration and dropped down with extending time. The allelopathy effect respectively were9.27%,10.93%,12.24%,18.74%after treated with the volatile of the seed, leaf, petiole, root of parsley of200g for144h. The parsley root volatile showed the strongest allelopathy, followed by the petiole, and third the leaf, and finally the seed. The incidence of cucumber was studied after inoculated bacteria, and the results showed that the allelopathy effect increased with increasing concentration and dropped down with extending time. The SOD activity, POD activity, CAT activity, Chitinase activity, PPO activity, PAL activity were higher than that of the contrast at the different time, and increased at first and then decreased; the content of MDA was lower than that of the contrast during the measurement period, and decreased at first and then increased. The SOD activity, POD activity, CAT activity, Chitinase activity, PPO activity, PAL activity increased with increasing concentration; the content of MDA dropped down with increasing concentration.6. The allelopathy, mechanism and allelochemicals identification of the root material and volatile of parsley on Fusarium oxysporium f.sp.cucumeris were studied comprehensively. The innovative points were as follows:①The allelopathy effects of the extrects of the root material of parsley on Fusarium oxysporium f.sp.cucumeris were studied to provide theoretical foundation for biological control of vegetable diseases and sustainable development.②The mechanism was studied from two perspectives of Fusarium oxysporium f.sp.cucumeris and cucumber seedlings, which made the research angle more comorehensively. Especially the liquid medium was used to study the changes of enzymes activity and material contents metabolized out from Fusarium oxysporium f.sp.cucumeris, which had not been widely applied.③The allelochemicals in the root and the rhizosperic soil of parsley were isolated, purificated and identificated to provide scientic basis for applicating allelochemicals in production practice.④The allelopathy of parsley volatile on Fusarium oxysporium f.sp.cucumeris was studied to explore the new field in the study of allelopathy, which provided a new train of thought for comprehensive prevention and treatment of vegetable diseases in many ways. |
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