【作者】 古丽君；

【导师】 徐秉良；

【作者基本信息】 甘肃农业大学 ， 作物保护， 2009， 硕士

【摘要】 1. 2007～2008年对兰州市13个小区混播草坪禾草根腐病症状表现和发病情况进行了调查,结果表明,发病严重的草坪禾草根腐病发病率为83.33﹪,病情指数为36.67。该病在草坪禾草不同部位上引起的症状不同,将其归纳为3种症状类型:叶尖黄化型、叶片中部缢缩型和根茎部褐变腐烂型。经对草坪禾草根腐不同发病部位进行分离培养,致病性测定等确定了引起草坪禾草根腐病的主要致病菌为腐霉属（Pythium . spp）的瓜果腐霉〔P.aphanidermatum （Edson） Fitzpatrick〕,根茎部病原菌分离频率达100﹪。潜育期测定结果表明在温度35℃,湿度90﹪的条件下该病原菌的潜育期最短为14～15h。2.草坪禾草根腐病的病原物瓜果腐霉〔P.aphanidermatum （Edson） Fitzpatrick〕的菌丝生长的温度范围为15³5℃,最适温度为30³5℃;最适宜的pH值为7⁸;全光照条件下菌丝生长速度最慢,全黑暗条件下菌丝生长速度最快,而紫外线的照射能加速菌丝的生长;较适宜的氮源为NH4NO3;较适宜的碳氮源为淀粉;病原菌在CAA培养基上生长速度最大,但是在PDA和TCA培养基上菌丝厚度最大。3.深绿木霉菌与瓜果腐霉对峙培养结果表明,深绿木霉（Trichoderma aureoviride）对引起禾草腐霉病原菌瓜果腐霉（Pythium aphanidermatum）有明显的抑制作用,并且可以包围、覆盖瓜果腐霉的菌落同时产生大量孢子;其孢子悬浮液的含孢量为4.65×10⁶个/ml时,对瓜果腐霉菌的抑制率达53.56﹪;通过深绿木霉菌孢子悬浮液和3种药剂对草坪禾草腐霉病病原菌抑制效果的比较,深绿木霉孢子悬浮液浓度为1×10⁷个/ml时与25﹪甲霜·霜霉的抑菌效果接近,分别为77.37﹪和79.57﹪。显微观察结果表明,深绿木霉菌丝缠绕在瓜果腐霉菌菌丝上,穿透菌丝在其内生长,或与瓜果腐霉菌的菌丝平行生长,再侵入瓜果腐霉菌内寄生。深绿木霉菌对瓜果腐霉的主要作用机制为重寄生作用。4.以深绿木霉菌为材料,探讨施于草坪禾草土壤后对土壤中细菌、放线菌、真菌3种微生物数量的影响。结果表明:土壤中微生物总体比较丰富,数量差异较大,各类菌群数量排序为细菌>放线菌>真菌。土壤中施入深绿木霉菌后明显引起微生物区系变化。土壤中的细菌的数量增加速度减缓,施入深绿木霉17d后,对照土壤细菌数量达到1.45×10¹¹ CFU/g,而施入深绿木霉的土壤中细菌的数量仅为1.96×10¹⁰ CFU/g;真菌的数量明显减少,对照土壤中的真菌数量从2549 CFU/g上升的4539 CFU/g,而施入深绿木霉的土壤中真菌的数量从2322 CFU/g下降到538 CFU/g;放线菌数量没有明显变化。5.通过测定菌落生长速度及单位面积产孢量,开展了微生物制剂多种常用助剂对高效生防真菌深绿木霉T2菌株的生物学相容性研究。所试载体中,硅胶处理与对照在菌落直径日增长量与单位产孢量无显著性的差异,对深绿木霉活力影响不显著;所试配伍农药中,甲霜霜霉3000X液与对照在菌落直径日增长量与单位产孢量均没有显著性的差异,对深绿木霉活力影响不明显;所试紫外保护剂中,腐殖酸对深绿木霉活力无明显影响。上述多种与深绿木霉T2菌株具良好生物学相容性助剂的确定,为深绿木霉生防制剂的研究提供重要依据。更多还原

【Abstract】 1. In 2007 and 2008, Pythium root rot of the truf grass was surveyed in 13 districts of Lanzhou City. The results showed that the incidence in the most serious fields was 83.33%, the disease index was 36.67. The disease caused different symptoms on different position of turf grass. Three types of symptoms on the turf grass were observed: Leaf tip blight, Leaf middle shrink and Rhizoma-brown rot. The chief pathogen, according to their morphology, cultural characteristics and pathogenicity, was identified as P.aphanidermatum (Edson) Fitzpatrick, the isolation frequency was 100% in rhizome. The incubation period for P.aphanidermatum (Edson) Fitzpatrick was 14～15 hours at 30℃and RH 90%.2. The hyphae of root rot pathogen for P.aphanidermatum (Edson) Fitzpatrick could grow from 15℃to 35℃, the rang of fit temperature was 20~25℃; optimal pH value was 7~8; The best cultural condition for hyphal growth was 24 h darkness while 24h illumination was the worst cultural condition. Ultraviolet Irradiation could accelerate the growth of hyphae; The best resourse of C are amylum , and the best resourse of N are ammonium nitrate; The pathogen hyphae could grow in CAA very well, in PDA and TCA the thickness of mycelium is bigger.3. According to confront culture, the Trichoderma aureoviride could inhibit the growth of Pythium aphanidermatum causing Turfgrass Root Rot. It could cover the P.aphanidermatum colony and produced large number of conidia. The effective concentration was at 4.65×10~6 cfu/ml, and the inhibitory effect reached 53.56%. Comparing the inhibition effect of T. aureoviride suspension with three kinds of fungicides against P.aphanidermatum, the T. aureoviride with the concentration of 107cfu/ml had the same effect as 25% metalaxyl. The inhibition rates were 77.37% and 79.57%, respectively. By Microscopic observation , the results showed that T. aureoviride either enwinded to the hyphae of P.aphanidermatum or grew parallel with the hyphae of P.aphanidermatum, then penetrated and parasitized in them. The main antagonistic mechanism of T. aureoviride against P.aphanidermatum was hyperparasitism.4. Trichoderma aureoviride was used in the study to describe the quantitative changes of bacteria,actinomycetes and fungi in soil of turfgrasses. The results showed that the amount of soil microbes was abundant , however , the difference of quantity among three microbes and the quantity from high to low was in the order : bacteria >actinomycetes >fungi . T. aureoviride could change the Soil Microflora significantly. The number of soil bacteria increased Slowly, the number of soil fungi decreased obviously and there was no obvious change in the actinomycetes.5. By measuring the speed of colony growth and sporulation per unit area, Carried out the biological compatibility about used additives and T. aureoviride. In the test of carriers, the silica gel and control were no significant difference; In the test of fungicide, the metalaxyl 3000X and Control was no significant difference; In the test of UV-protector, the humic acid no significant impact on the vitality of T. aureoviride. Determined the additives which had good biological compatibility with the T. aureoviride, provided an important basis for T. aureoviride biocontrol preparation更多还原