大豆根际土壤镰孢菌不同分离方法比较

镰孢菌(Fgsarium)引起的大豆根腐病是难防治的土传病害之一.土壤中镰孢菌多样性水平很高,并对其中致病菌种群动态及寄主抗性表现有一定影响.镰孢菌分离在其多样性研究中起重要作用,报道的镰孢菌分离方法很多,但分离效果有一定差异.本文对影响分离效果的相关内容进行了研究,比较了稀释平板法和土粒平板法.结果表明,当抗生素浓度增加到常量的4倍时可很好抑制细菌,并对真菌数目没有显著影响;不同抗生素组合对镰孢菌分离有一定影响;无菌水和水琼脂处理不同样品量与菌落数(CFU)之间均呈线性关系(R2>0.9),随着样品量的增加菌落数呈递增趋势;无菌水处理中镰孢菌的分离比率为21.0%,略高于水琼脂处理的10.0%;供试2种培养基对镰孢菌分离比率没有显著影响,与孔雀绿琼脂培养基(MGA)相比,蛋白胨.五氯硝基苯琼脂培养基(PPA)对镰孢菌的分离比率较高为20.93%.培养方法对镰孢菌分离比率影响较大,土粒平板法分离比率均大于60.0%,远高于稀释平板法(分离比率均低于6%).

Comparing Different Methods for Isolating Fusarium from Soybean Rhizosphere Soil

Fusarium root rot of soybean is one of the soil-borne diseases which is difficult to control. In soft, distribution of Fusarium is surprisingly diverse,which can efficiently influence the pathogenic Fusarium populations and host resistance. Isolation of Fusarium is very useful in the study of soil Fusarium diversity. Many methods for the isolation of Fusarium have been reported,but the efficiency was certainly different. In this paper,some related contents which affect the effeciency of Fusarium separation were researched, and dilution plate method and direct soil plating method were compared. The results showed that bacteria could be inhibited excellently when the concentration of antibiotic reached fourfold, but there was no significant impact on the number of fungi. Interestingly ,it seems that different combination of antibiotics had effect on Fusarium isolation. Between colony forming units (CFU) of fungi and different sample volume,well linear relationship were de tected in both sterile water and Water Agar treatment(R2 ＞ 0.9). The isolation rate of Fusarium in sterile water treatment was 21.0%, a bit higher than that in Water Agar treatment, which was 10.0%. No significant effects on Fusarium isolation between two culture media were observed. Compared with Malachite Green Agar (MGA),Peptone PCNB Agar (PPA) behaved higher isolation rate of Fusarium which was 20.93%. The difference between Fusarium isolation rates derived from two culture methods were significant. The isolation rate of Fusariurn derived from direct soil plating method were all above 60.0% ,which is significantly higher than that derived from dilution plate method which were all below 6%.