The Safety Of The Herbicide On Bletilla Striata And Its Effect On The Symbiotic Mycorrhizal Bacteria And Root Soil Microorganisms

In order to screen out herbicides that can effectively control weeds in Bletilla striata field and are safe for Bletilla striata and its symbiotic mycorrhizal fungi and root soil microorganisms.24 common herbicides were used as test agents,annual Bletilla striata seedlings were used as test crops,and Bletilla striata mycorrhizal fungi KB-3(fluorescent),G3,and G4 were used as test strains.The efficacy and safety of herbicides against weeds in Bletilla striata field and its effect on symbiotic mycorrhizal fungi in Bletilla striata were verified by laboratory test and field efficacy test,and the effects of 35% pendimethalin SC and 50% acetochlor EC on soil microbial diversity and community structure of Bletilla striata root system were investigated.The research results are summarized as follows: 1?Phytotoxicity test of 24 herbicides on annual Bletilla striataIn order to understand the influence of herbicides on Bletilla striata and to screen out the herbicides that is not harmful to Bletilla striata,24 common herbicides were used to conduct the experiment on the harm of annual Bletilla striata by indoor potted culture.The experimental results show that: 50% acetochlor EC,960 g/L s-metolachlor EC,60% Flufenacet WG,75% halosulfuron-methyl WG,25% rimsulfuron WG,10% pyrazosulfuron-ethyl WP,40 g/L nicosulfuron OD,50% isoproturon WP,10% quizalofop-P-ethyl EC,69 g/L fenoxaprop-P-ethyl EW,108 g/L haloxyfop-P-methyl EC,35% pendimethalin SC,30% anilofos EC,75% clopyralid SG,15% mesotrione EC and 30% benazolin?ethyl SC have no harmful to the annual Bletilla striata at the highest recommended amount of active ingredients in the field,2?Effects of 5 herbicides on Bletilla striata and its mycorrhizal fungiIn order to determine the influence of herbicide on Bletilla striata and its mycorrhizal fungi,the inhibition of 15 herbicides on KB-3,G3 and G4 was determined by mycelia growth rate method.The effects of 5 herbicides on the amount of KB-3 in Bletilla striata and its rhizosphere were studied by pot experiment.The results of the plate experiment show that: under the experimental dose,the inhibition rate of KB-3 by 98% Flufenacet TC,95% halosulfuron-methyl TC,97% nicosulfuron TC,96.3% rimsulfuron TC,96% quizalofop-P-ethyl TC,95% fenoxaprop-P-ethyl TC,95% haloxyfop-P-methyl TC and 98% pendimethalin TC was-5.42% ? 7.75%,and the inhibition rate of G3 was-2.94% ?3 2.05%,and that of G4 was-10.16% ? 34.55%.The results of pot experiment show that: under the experimental dose,500 g/L Flufenacet SC,35% pendimethalin SC,25% rimsulfuron WG,108 g/l haloxyfop-P-methyl EC and 75% halosulfuron-methyl WG had no significant effect on KB-3 and no harmful symptoms on Bletilla striata.3?Effect of 5 herbicides on annual weeds in Bletilla striata fieldIn order to determine the weed control effect of herbicide in Bletilla striata field and the safety of Bletilla striata,two kinds of soil treatment agents and three kinds of stem and leaf treatment agents were used in the field experiment,and the damage of Bletilla striata was recorded.The results of experiment show that: under the test concentration,the control effect of 500 g/L Flufenacet SC,35% pendimethalin SC on weeds was higher than 91%,and the control effect of grass was better than that of broad-leaved grass.The control effect of 25% rimsulfuron WG,108 g/L haloxyfop-P-methyl EC and 75% halosulfuron-methyl WG on weeds was higher than 91%.5 herbicides can effectively control weeds in Bletilla striata field and are safe for Bletilla striata.4?Effects of two herbicides on soil microbial diversity and community structure of rhizome of Bletilla striataAs clear herbicide to Bletilla striata's root soil microbial diversity and community structure and the effect of using the Illumina Miseq high-throughput technique.The fungi ITS1-ITS2 region and the bacteria VS-V4 region of 16 S r RNA in the soil samples collected 3,7,14,and 21 days after application of 35% pendimethalin SC and 50% acetochlor EC were sequenced and analyzed the changes in its diversity and community structure.Experimental results show that: in the short term,the concentration treatment of 35% pendimethalin SC 1750 mg/kg and 50% acetochlor EC 2250 mg/kg of fungi in the soil have no obvious effect on the diversity and richness,35% pendimethalin SC 1750 mg/kg in 21 d after the drug was significantly reduced the richness of bacteria in the soil,have no obvious effect on other period,50% acetochlor EC 2250 mg/kg in each period were significantly reduce the richness of bacteria in the soil.The concentration treatment with 35% pendimethalin SC 1750 mg/kg had no significant effect on the richness of unclassified fungal communities of Ascomycota,Mortierellomycota,Chytridiomycota,Basidiomycota,Olpidiomycota and unclassified?k??Fungi.The concentration of 50% acetochlor EC 2250 mg/kg significantly reduced the community richness of Mortierellomycota,and increased the community richness of Basidiomycota,Olpidiomycota and unclassified?k??Fungi.The concentration treatment with 50% Acetochlor EC 2250 mg/kg significantly increased the community richness of Proteobacteria and Firmicutes,and reduced the community richness of Actinobacteria,Chloroflexi and Acidobacteria.While the effect of 35% pendimethalin SC 1750 mg/kg on the richness of various groups of bacteria was significantly less than that of 50% acetochlor EC 2250 mg/kg.