| Cucumber Fusarium wilt is a soil-borne disease which is caused by Fusarium oxysporum.The traditional chemicalmethods will do damage to environment humans bodies,.BesiedsA long-term use of chemicals will lead to drug resistance and lose the effect.Biological control is widely welcomed with its excellent control effect and it is harmless to the environment.Using environmental-freiendly and plant beneficial biocontrol to prevent some plant diseases has been the concern among the majority of researchers.Penicillium is widely found in the nature,as a fungi,which is widely known by the application of penicillin secretion in medical areas.Penicillium not only has a wide range of uses in medicine,but also has been proved in botanical research that Penicillium can improve the activity of enzymes related to plant resistance,inhibit growth of pathogen and prevent disease spreading in soil.It has vital effecton the control of plant diseases,and also benefit to plant photosynthesis and nutrient uptake.In this experiment,fungi with antagonistic effect on cucumber fusarium wilt were isolated and screened from the base of distiller's grains,and then identified the isolated fungi.The culture characteristics,morphological characteristics and 18SrDNA molecular identification were determined to confirm the type of antagonistic fungi.The potentiation of the selected antagonistic fungi was carried out to detect the control effect of antagonistic fungi on the fusarium wilt in cucumber.Then the effects of antagonistic fungi on the growth of cucumber seedlings were further investigated.The results can provide the theoretical basis for the research on the control of cucumber fusarium wilt.The main findings are as follows:J3?J13 and NSY15 were isolated from the base of distiller's grains.According to morphological characteristics,culture characteristics and 18SrDNA gene sequence analysis,these strains were identified as Penicillium.The bacteriostatic ability to Fusarium oxysporum.sp.fusarium wilt of three strains was compared by PDA medium culture.The results showed that NSY15 had strong antagonistic effect on Fusarium oxysporum f.sp.fusarium wilt wich can inhibit.51%Fusarium mycelium in the medium.In addition,the ability of phosphorus uptake of three strains was detected by conducting a assay in the dissolving phosphate medium,which indicated that the ability of dissolving phosphorus of strain NSY15 was significantly higher than that of other strains.Using turf and roseite(v:v=2:1)as the substrate to investigate the effect of NSY15 on the wilt.The results showed that the number of bacteria and actinomycetes increased after the inoculation of NSY15,but the number of fungi decreased,so that the soil microbial community get better.The activities of CAT?POD?SOD and other enzymes in cucumber plants after inoculation were significantly increasedbut the accumulation of MDA was significantly decreased compared with that of diseased plants.The disease index of cucumber fusarium wilt after using Penicillium NSY15 decreased by 24.5%,and control effect reached 52.39%.The results suggested that Penicillium could improve the activity of related enzymes in cucumber and balance the number of microbes in cucumber rhizosphere,which had significant effect on controlling cucumber fusarium wilt.The results showed that the net photosynthetic rate,stomatal conductance and other photosynthetic indexes of the leaves in cucumber seedlings treated with NSY15 significantly increased which indicated it can significantly enhance the photosynthesis.The absorption of nutrients in cucumber plants,especially phosphorus was also pronounced improved.The application of NSY15 spore suspension in cucumber seedlings could increase the fresh and dried weight ofshoots and roots in cucumberThe growth of roots was higher than that of control,which promoted the growth of plants. |
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