【作者】 周蕾；

【导师】 王世梅； 姜小三；

【作者基本信息】 南京农业大学 ， 农业硕士（专业学位）， 2022， 硕士

【摘要】 草莓的根腐病是一种土传真菌病害,严重影响草莓产量和品质。由于化学农药对病害防治不彻底,而且对环境和人类健康带来了不可逆转的伤害,因此,绿色生物防控成了研究的重点。放线菌代谢产生大量活性物质,在防控土传病害方面起重要作用。本文以实验室保存的两株拮抗放线菌CT205(Streptomyces albospinus)和B04(Streptomyces hygroscopicus)为材料开展实验。首先通过确定菌株B04和CT205的选择性培养基,测定这两种微生物菌剂施入土壤中的动态数量变化。然后通过固体发酵制备固体菌剂,通过盆栽试验,确定两种菌剂蘸根施用的最佳稀释浓度。最后,通过田间试验研究B04和CT205对草莓(红颜和越心)根腐病的生防效果及促生作用,研究结果如下:通过筛选确定菌株B04的选择性培养基为添加50μg/m L氨苄西林和50μg/m L呋喃唑酮两种抗生素的高氏一号培养基。且通过试验验证菌株CT205在加入氨苄西林50μg/m L和阿莫西林100μg/m L的选择性培养基上生长良好。土培实验发现,两种菌剂施入土壤之后数量变化均是是先降低后增加又降低,施加菌剂时CT205菌剂的起始活菌数量为2.6?10~8CFU/g,B04菌剂的活菌数量为6.8?10~8CFU/g。21天之后,菌株数量逐渐降低,CT05的活菌数量降低为7.5?10~7 CFU/g,B04的活菌数量降低为5.4?10~7 CFU/g。盆栽试验结果表明,初始浓度为10~9 CFU/g的CT205和B04固体菌剂,分别稀释10、30、50、80、100倍,每颗苗取10 m L蘸根施用,结果表明,高浓度的菌剂对植株生长有负面影响,稀释100倍的菌剂不影响植株的生长,和对照相比,100倍稀释菌剂处理的植株生长旺盛,菌剂促生作用显著,在施加CT205和B04菌剂后,草莓植株的叶绿素含量分别增加了9.8%和10.3%地上部分鲜重分别增加了45.3%和41.3%,地下部分鲜重分别显著增加了49.6%和39.4%。田间试验表明,CT205菌剂的防控效果比B04菌剂的防控效果好。将CT205和B04菌剂稀释100倍后施用,对草莓红颜的防控效果分别为46.19%和12.9%,对草莓越心的防控效果分别为65.41%和39.8%。而且施加两种菌剂后对草莓的品质有很大的提升。和空白对照相比,施加CT205菌剂处理后草莓红颜的平均重量提高了75.7%,可溶性固形物的含量增加了18.2%,维生素C含量增加了25.7%,可溶性糖的含量增加了6.1%,可滴定酸的含量降低了15.5%,糖酸比增加了26.85%;施加B04菌剂后草莓越心的平均重量增加了52.64%,可溶性固形物的含量增加了12.4%,维生素C含量增加了14.3%,可溶性糖的含量增加了10.5%,可滴定酸的含量降低了16.5%,糖酸比增加了32.19%。表明两种放线菌菌剂对草莓根腐病有一定的防控效果。综上所述,CT205和B04菌剂(10~9 CFU/g)最佳施用剂量是稀释100倍,每颗苗10 m L蘸根。施加菌剂对植株有促生作用,根腐病的防控效果较好,草莓果实的品质也有较大提升。更多还原

【Abstract】 Strawberry root rot is a soil borne fungal disease,which seriously affects the yield and quality of strawberry.Because chemical pesticides do not prevent and control diseases thoroughly,and bring irreversible damage to the environment and human health,green biological prevention and control has become the focus of research.Actinomycetes metabolize to produce a large number of active substances,which play an important role in the prevention and control of soil borne diseases.In this paper,two antagonistic including Streptomyces albospinus CT205 and Streptomyces hygroscopicus B04 preserved in the laboratory were used as materials for experiments.Firstly,by determining the selective medium of strains B04 and CT205,the dynamic quantitative changes of the two microbial agents applied to soil were determined.Then the solid bacterial agents were prepared by solid fermentation.Through pot experiment,the best dilution concentration of the two bacterial agents dipped in roots was determined.Finally,the biocontrol effect and growth promoting effect of B04 and CT205 on Strawberry(Hongyan and Yuexin)root rot were studied through field experiments.The results are as follows:Through screening,the selective medium for actinomycete B04 was determined as adding 50 ug/m L ampicillin and 50 ug/m L furazolidone.And the test verified that strain CT205 can grow well on the selective medium added with ampicillin 50 ug/m L and amoxicillin 100 ug/m L.The soil culture experiment found that the quantity of the two actinomycetes agents decreased first,then increased and then decreased after they were applied to the soil.When the bacterial agent was applied,the viable count of CT205 was 2.6?10~8 CFU/g,and the viable count of B04 was 6.8?10~8 CFU/g.After 21 days,the number of strains decreased gradually,the viable count of CT05 decreased to 7.5?10~7 CFU/g,and the viable count of B04 decreased to 5.4?10~7 CFU/g.The results of pot experiment showed that the initial concentration of 10~9 CFU/g of CT205 and B04 solid inoculants were diluted 10,30,50,80 and 100 times respectively,and each seedling was applied with 10m Lof inoculants dipped in roots.The results showed that the high concentration of inoculants had a negative effect on plant growth,and the 100 times diluted inoculants did not affect plant growth.Compared with the control,the plants treated with 100 times diluted inoculants grew vigorously,and the growth promoting effect of inoculants was significant.After the application of CT205 and B04 inoculants,the chlorophyll content of strawberry plants increased by 9.8%and 10.3%respectively,the fresh weight of aboveground parts increased by 45.3%and 41.3%respectively,and the fresh weight of underground parts increased significantly by 49.6%and 39.4%respectively.The field experiment showed that the control effect of CT205 was better than that of B04.When CT205 and B04 were diluted 100 times,the control effect on strawberry Hongyan was 46.19%and 12.9%respectively,and the control effect on strawberry Yuexin was 65.41%and 39.8%respectively.Moreover,the quality of strawberry was greatly improved after applying two kinds of inoculants.Compared with the blank control,the average weight of strawberry Hongyan treated with CT205 increased by 75.7%,the content of soluble solids increased by 18.2%,the content of vitamin C increased by 25.7%,the content of soluble sugar increased by 6.1%,the content of titratable acid decreased by 15.5%,and the sugar acid ratio increased by 26.85%;The average weight of strawberry Yuexin increased by 52.64%,the content of soluble solids increased by 12.4%,the content of vitamin C increased by 14.3%,the content of soluble sugar increased by 10.5%,the content of titratable acid decreased by16.5%,and the sugar acid ratio increased by 32.19%.The results showed that two kinds of actinomycetes had certain control effect on strawberry root rot.To sum up,the best dosage of CT205 and B04 bacterial agents(10~9 CFU/g)is 100 times diluted,and 10m L of each seedling is dipped in the root.The application of fungicides can promote the growth of plants,the control effect of root rot is better,and the quality of strawberry fruit is also greatly improved.更多还原