Screening Of Endophytic Fungi Of Ambrosia Artemisiifolia For Inhibition Of Seed Germination And Optimization Of Fermentation Conditions

In this paper,the studied effects of Ambrosia artemisiifolia endophytic fiungal fermentation broth on seed germination and seedling growth in the seeds of Ambrosia artemisiifolia in Changle City,Fujian Province.The results showed that seed germination of ragweed inhibited by 17 strains of endophytic fungi such as strain AM-8,AM-13,AM-16,AM-17,AM-38,AM-40,AM-47,AM-50,AM-56,AM-65.Among them,the strains which showed best inhibitory activity were AM-8 and AM-17.And the two strains were identified as fungal strains of Alternaria.The colonies of these two strains were significantly different in 7 mediums.The growth rate of strain AM-8 was the best on PDA medium,and the sporulation rate was the best on rice culture medium.The optimum temperature for AM-8 mycelia growth was 28 ?.The mycelial growth of AM-8 had strong adaptability to weak acid and weak alkaline environment,and could grow in the range of initial pH 4.0?8.0,and the mycelial growth was different.The germination of ragweed seeds was observed every 2 weeks,and the germination of ragweed seeds was inhibited by the fiungi AM-8 fermentation broth.The germination of ragweed seeds treated with fungi AM-17 was delayed.The effects of different liquid fermentation conditions on the biomass of the fungus AM-8 were studied.The optimum fermentation conditions were as follows:temperature 26 °C,pH 7.0,Speed 180 r/min,inoculation amount of 5 bacteria cake,the diameter of the cake is 0.8 cm.The strain mycelial biomass reached 556.00 i 23.00 mg/100 mL under the optimum culture medium and culture conditions for 3 daysThe growth of the seeds of the wild plant and the growth of the native plant stem(Stellaria media(L.)Cyr.)The results showed that AM-17 fermentation broth had a significant effect on the growth of shoots and the number of roots in the shoots,the obvious inhibitory effect.Effects of fungi AM-8 and AM-17 on the growth competition of rapeseed seedlings and coriander seedlings treated with fungal fermentation broth were studied separately on Ambrosia artemisiifolia and planted native plant coriander chrysanthemum plant height has inhibitory effect on the underground planted Ambrosia artemisiifolia underground rhizome has a significant inhibitory effect,and thecompetition in the underground grass rhizome has a catalytic role in the competition plant coriander chrysanthemum than the separate planted coriander chrysanthemum underground rhizome The inhibitory effect becomes smaller.It was found that the rhizome of Ambrosia artemisiifolia became more stronger with the increase of the number of Ambrosia artemisiifolia in a certain range.