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采用稀释平板涂布法,从天津市和河北省地区采集的48份盐碱土中分离筛选得到20株耐盐碱木霉菌株,在含8%NaCl,pH 8.0的PDA培养基中培养7 d,菌落直径达1.0~5.9 cm。通过平板对峙培养和发酵液活性测定得到6株对Phytophthora nicotianae ACCC38065具有较好拮抗作用的菌株。其中,菌株28TJ19对Phytophthora nicotianae ACCC38065的拮抗效果最好,平板对峙和发酵液抑制率分别为52.8%、71.6%,其次为菌株28HB14(41.7%,76.2%)、29HB16(41.7%,67.3%)。利用形态学观察、ITS序列分析以及TEF序列分析对这6株菌株进行分类鉴定,4株菌株鉴定为哈茨木霉(Trichoderma harzianum),另外2株为长枝木霉(Trichoderma longibrachiatum)。经盆栽试验发现,这6株菌对烟草黑胫病均具有不同程度的防治效果,菌株29TJ04、29HB16的防效最好,达100%。
Twenty isolates of Saline - resistant Trichoderma spp. Were isolated and screened from 48 saline - alkali soils collected in Tianjin and Hebei Provinces by dilution plate coating method and cultured in PDA medium containing 8% NaCl and pH 8.0 for 7 days. Colony diameter of 1.0 ~ 5.9 cm. Six strains with good antagonistic activity against Phytophthora nicotianae ACCC38065 were obtained by plate confrontation culture and fermentation broth activity assay. Among them, strain 28TJ19 had the best antagonistic activity against Phytophthora nicotianae ACCC38065. The inhibitory rates of plate confrontation and fermentation broth were 52.8% and 71.6% respectively, followed by strains 28HB14 (41.7%, 76.2%) and 29HB16 (41.7%, 67.3%). The six strains were identified by morphological observation, ITS sequence analysis and TEF sequence analysis. Four strains were identified as Trichoderma harzianum and the other two strains were Trichoderma longibrachiatum. The pot experiment showed that the six strains had different degrees of control effect on tobacco black shank. The strains 29TJ04 and 29HB16 had the best control effect, reaching 100%.