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期 刊 ：植物保护学报 2006年

关键词：画眉草弯孢霉；长孺孢素；抗生素；马唐；除草活性；

Keywords:Curvularia eragrostidis, Digitaria sanguinalis, helminthosporin, antibiotic, herbicidal activity,

摘 要 ：为了分离鉴定马唐Digitaria sanguinalis (L.) Scop生防菌画眉草弯孢霉Curvularia eragrostidis菌株QZ-2000的生物活性物质以及评价该物质是否具有作为生物源除草剂的潜力,利用生物测定为导向的色谱分离、质谱和核磁共振波谱技术对该菌分泌的毒素进行了分离和鉴定,利用种子萌发、胚根和芽生长的抑制及离体叶片针刺法测定了该毒素对马唐的毒害作用,并测定了毒素的专化性及毒素对马唐叶绿素含量的影响。结果表明,该化合物为桔黄色晶体,熔程为225~227℃,经质谱和NMR数据分析确定该化合物分子式为C₁₅H₁₀O₅,并确定为长孺孢素(helminthosporin)。该毒素在150 μg/mL浓度下,对马唐胚根生长抑制率达44.59%;当毒素浓度达到200 μg/mL时,叶绿素含量下降18.41%;在500 μg/mL浓度下,毒素对供试的23种杂草产生的毒害程度不同,其中小藜对毒素最为敏感,其次为马唐、萹蓄、菵草、藜和日本看麦娘等恶性杂草。在供试的5种作物中大豆、棉花和番茄对毒素不敏感,但玉米和小麦则较为敏感。上述结果表明,长孺孢素作为大豆和棉花田苗后生物源除草剂有一定的开发潜力。

Abstract:The bioassay-guided column chromatography and TLC on silica gel, and MS, ¹H- and ¹³C-NMR spectral techniques were used to isolate and determinate the structure of antibiotic from Curvularia eragrostidis QZ-2000, and to evaluate its herbicidal activity. The herbicidal activity of the toxin to D.sanguinalis was tested by seed germination, the elongation of root and shoot. The needle puncturing leaf assay techniques were used to test the specificity and effect of toxin on photosynthetic pigment content of D.sanguinalis. MS, ¹H- and ¹³C-NMR spectral data indicated that the toxin is helminthosporin. The melting point of the toxin is 225-227℃, and the molecular formula is C₁₅H₁₀O₅. The toxin had inhibitory effect on elongation of D.sanguinalis root. At 150 μg/mL concentration, the inhibition of the toxin to root elongation reached 44.59%. Helminthosporin showed impact on photosynthetic pigment content of D.sanguinalis leaf. When the concentration of toxin reached 200 μg/mL, the chlorophyll content of D.sanguinalis leaf decreased by 18.41%. Twenty three troublesome weeds and five crops were tested to study specificity of helminthosporin. The result showed that 18 out of the 28 species were susceptible to the toxin. Chenopodium serotinum is the most susceptive, and D.sanguinalis, Polygonum aviculare, Beckmannia syzigachna, Chenopodium album and Alopecurus japonicus took second place. Soybean, cotton, tomato, Amaranthus retroflexus and Echinochloa crus-galli were resistant to toxin at 500 μg/mL concentration. Helminthosporin produced by C.eragrostidis QZ-2000 could be developed as a biocontrol agent for weed control in soybean and cotton fields.

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