| This paper used the Elymus dahuricus seed with endophyte as experimental, and treated the essds of these different methods: high temperature treatment, fungicide treatment and microwave treatment. The effects of these different methods on mortality of endophyte of E.dahuricus were studied after the endophyte was treated at the different treatment. And the E.dahuricus germination vigor was also evaluated. Both the infection rate and germination vigor as measured by a common standard. We expected to get the appropriate method which can kill the endophyte and do not affect the growth of the host. The results are as follows:(1)In this study microwave treatment was used to construct endophyte-free populations of E. dahuricus. The effects of microwave treatment on mortality of endophyte of E.dahuricus were studied after the endophyte were treated at the microwave power of 150 W for30 s, 40 s, 50 s, 55 s, 60 s ? 65 s. E. dahuricus germination vigor was also evaluated. The results indicated that microwave treatment was effective in killing the endophyte in the seeds.While the endophyte were treated at 150 W for 40 s, the contamination rate significantly dropped below 27.3% respectively(P?0.05), compared with the control. At the same time,the germination rate, hypocotyls length, radical length, plant height and seeding fresh weight were also promoted after microwave processing, and germination potential, germination index and vital index of E. dahuricus had no significant effect compared with the control(P?0.05).But the E. dahuricus germination vigor was hurted when encountered the stronger microwave processing. The result showed that the solution of 150 W treated seeds in 40 s was the best way to eliminate fungal endophyte of E. dahuricus.( 2) In this study high temperature(60°C, 70°C and 75°C) treatment was used to construct epichlo?-free populations of E. dahuricus. The results indicated that high temperature treatment was effective in killing the epichlo? in the seeds. After 75°C for 20days' treatment,the contamination rate significantly dropped from 93.17% to 0 respectively(P?0.01), seedlings were all uninfected. When the E. dahuricus seeds were treated with 75°C for 20 d, germination rate, germinating potential, germination index, vital index and seeding fresh weight increased by 4.8%, 1.2%, 18.8%, 1.4% and 68.33% respectively, the radical length and hypocotyls length significantly increased by 36.37%, 73.94%, 50.38%, 63.38%and 7.79% respectively(P?0.05). At the same time, high temperature improved hypocotyls and radical growth of the treated seedlings by 0.54% and 14.43%. Therefore, this method was an effective way to construct epichlo?-free populations of E. dahuricus. And this method also provides some academic bases and references of getting epichlo?-free populations of grass.(3)Thiophanate-methyl ? had four concentrations(500TM, 400 TM, 300 TM, 200TM)and four distinct times(4, 6, 8, 10 h) respectively. The results indicated that the 6 h treatment of 500-fold dilution TM reduced endophyte infection was significantly(P ? 0.05) from93.17% to 20.00%. Meanwhile, there had no significant effect on germination rate(P?0.05).Therefore, the solution of 500-fold dilution thiophanate-methyl treated seeds in 6 h was the best way to eliminate fungal endophyte of E. dahuricus.(4)Re-screening of the following methods: 150 W treated seeds in 40 s, 75°C high temperature treated seeds for 20 days, 500-fold dilution thiophanate-methyl treated seeds in 6h, 60°C heated water bath for 20 min. The results indicated that the solution of 75°C high temperature treated seeds for 20 days is more desirable campared with other methods. |
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