Analysis On The Causes Of Continuous Cropping Obstacle Of Dictyophora Indusiata

At present, the cause and mechanism of continuous cropping obstacles waswell studied by many scholars and experts home and abroad. However, thosestudies were mainly focused on vegetables, fruit trees, herbs, and food crops and soon, while rarely on edible fungus. In this paper, the cause of continuous croppingobstacles of Dictyophora indusiata was firstly analyzed from the soil microflora andsoil enzyme activity. Then the Metabolomics was introduced. HPLCthree-dimensional dynamic trends figure of soil samples which were collectedduring multiple periods from the Dictyophora indusiata testing-soil was obtained toexplore a new way to research the cause of continuous cropping obstacles ofDictyophora indusiata. The main results were as follows:(1) After continuous cropping of Dictyophora indusiata, soil microbial florachanged，the dynamic changes of bacteria’s amount: the overall trend of thebacteria’s amount in the soil from one-year planting zone and two-years plantingzone were similar, which at first went up and then decreased that showed a trend ofups and downs like waves; Changes of soil actinomycetes in different planting yearsof Dictyophora indusiata: the overall change was that after continuous croppingtwo years of Dictyophora indusiata, the amount of actinomycetes increasedsignificantly compared to the amount from last year; The trend of fungus was: in thesoil from one year continuous cropping zone when Dictyophora indusiata wasthriving, the amount of fungus reached to peak, while during other stage the amountof fungus was similar to the amount of fungus from one-year continuous croppingof Dictyophora indusiata.(2) Changes in the amount of micro-organisms with the specific function: thenumbers of aerobic cellulose-decomposer, ammonifier, denitrifier, anaerobicazotobacter and nitrite bacteria were consistent basically; The numbers of bacteriaincreased obviously with the continuous-cropping years, the trend of change wasthat:2years>1year>control, while the trend of the amount of anaerobic, cellulose-decomposer and aerobic azotobacter was different from other groups, thetrend of change was that:1year>2years> control.(3) In the different treatment of the soil, the activities of urease, catalase,polyphenol oxidase and protease were significantly diverse. Compared with those inthe soil cropped Dictyophora indusiata for one year, the activities of urease andcatalase increased by84.23％and17.14％in the soil successively croppedDictyophora indusiata for two-year. But the activities of polyphenol oxidase andprotease in the soil were inhibited with the continuous-cropping years, and theactivities of polyphenol oxidase and protease were respectively reduced by14.67％and5.83％. However, the activities of peroxidase in the soil cropped Dictyophoraindusiata for one year and for two-years didn’t difference significantly.(4) Bacillus megaterium and its fermentation inhibited the mycelial growth ofDictyophora indusiata significantly, and the inhibition of Bacillus megaterium tomycelial growth of Dictyophora can reach to58.37％, while the inhibition fromfermentation of bacillus megaterium can reach to64.81％.(5) The methods of metabolomics and the technology of three-dimensionaltarget was utilized to analyse soil component in the soil cropped Dictyophoraindusiata, and soil markers would be identified.Combining with the changing trendfigure of microbial amount in the soil and the growth of Dictyophora indusiata, thetime point of the significant change of microbial metabolites and metabolites fromDictyophora indusiata was selected, according to the principle that the changingcharacteristics from the other markers could be avoided effectively, to determine thetest sample and the sampling time for the design of experiment which studied theeffect of microbial metabolites and metabolites from Dictyophora indusiata on thegrowth of Dictyophora indusiata.