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根据供试放线菌‘D74’菌株的菌落形态特征及16S r RNA基因序列分析,确定其为娄彻氏链霉菌(Streptomyces rochei)。采用皿内拮抗试验研究表明,‘D74’对魔芋软腐病菌有较强的拮抗作用,拮抗圈直径为11.0~18.3 mm。用‘D74’无菌发酵滤液10倍稀释液处理甜瓜种子,其发芽率、简明活力指数、胚轴和胚根长度分别较对照增加34.9%、82.4%、66.4%和31.5%(P<0.05)。盆栽条件下,拌土单接菌剂D74和菌剂与病原菌混接处理对收获期魔芋的相对防效分别为100%和17.0%。菌剂D74在单接和混接条件下能提高盆栽魔芋叶片光合作用、叶片绿色度(SPAD)、生物量及产量,亦能改善魔芋球茎品质。田间小区试验条件下,菌剂D74穴施,魔芋叶片光合指标、生物量及产量较对照增加。研究表明,放线菌‘D74’对魔芋软腐病菌有较强抑制作用,‘D74’活菌制剂对魔芋有良好的防病促生效果,对魔芋品质也有显著的改善作用。
According to the colony morphological characteristics of the tested actinomycete ’D74’ strain and the 16S rRNA gene sequence analysis, it was confirmed that it was Streptomyces rochei. Antagonistic experiments using the dish showed that ’D74’ had a strong antagonistic effect on soft rot of Konjak, and the diameter of antagonistic circle was 11.0-18.3 mm. The germination rate, concise vigor index, hypocotyl and radicle length increased by 34.9%, 82.4%, 66.4% and 31.5% (P <0.05) compared with the control, respectively. . Under potted condition, the relative control effects of mixed single-inoculant D74 and fungi with pathogenic bacteria were 100% and 17.0%, respectively. D74 could increase photosynthesis, leaf greenness (SPAD), biomass and yield of potted konjac in single and mixed conditions, and also improve the quality of konjac. Under field conditions, photosynthetic indexes, biomass and yield of fungi agent D74 and konjac were increased compared with the control. Studies have shown that actinomycetes ’D74’ konjac soft rot bacteria have a strong inhibitory effect, ’D74’ viable preparations of konjac has a good disease-prevention and promoting effects on the quality of konjac also significantly improved.