除虫菊内生拟盘多毛孢Y1菌株的生物学特性及其对植物病原菌的抑制作用

    从除虫菊叶中分离到1株内生真菌,经形态学和生长特性等研究初步鉴定其为半知菌类拟盘多毛孢(Pestalotiopsis sp.).该菌发酵液的10倍稀释液对苹果炭疽病菌(Glomerella cingulata)、番茄灰霉病菌(Botrytis cirerea)、玉米大斑病菌(Exserohilum turcicum)等6种病原真菌的抑制作用均达到85%以上,其5倍稀释液对番茄灰霉病菌、玉米大斑病菌、苹果炭疽病菌的孢子萌发抑制率均达80%以上.盆栽试验中对小麦白粉病(Blumeriagraminis)、番茄灰霉病、黄瓜霜霉病(Lycopersicon esculentum)的防治效果达60%以上.环境和营养因子对该菌的生长繁殖和抑菌活性影响较大:①在10～35℃时,菌丝能生长并形成孢子,最适生长繁殖温度为30℃,孢子的致死温度为65℃;②在pH 6.5～8.0时,菌丝生长、孢子形成和萌发均良好,最适pH值为7.5;③能直接利用玉米粉和糊精;④氮源以有机态氮为佳,硝态氮对其生长繁殖有抑制作用;⑤分别以D-木糖、山梨糖、甘露醇为碳源,以硝酸钠、甘氨酸、硫酸铵、牛肉膏、蛋白胨为氮源培养时,该菌株发酵液抑菌活性较高.     

除虫菊愈伤组织诱导研究

以除虫菊种子获得的无菌苗的不同器官为外植体,研究几种基本培养基及NAA、2,4-D或其与BA、KT的组合对愈伤组织的诱导效果,结果表明：不同类型基本培养基中MS有利于子叶、真叶和下胚轴,White有利于根愈伤组织的诱导和生长。不论除虫菊的哪一部分作为外植体,培养基pH值均为5.8较为合适。不同器官外植体诱导愈伤组织的最适植物生长调节剂组合不同,子叶为1.0 mg/L 2,4-D＋0.5 mg/L KT,真叶为1.0-2.0 mg/L 2,4-D＋0.5 mg/LKT,根为0.5 mg/L 2,4-D＋0.5 mg/L BA或KT,而下胚轴在1.0-2.0mg/L 2,4-D＋0.5 mg/L BA,0.5-1.0 mg/L 2,4-D＋0.5 mg/L KT,1.0 mg/L NAA＋0.5 mg/L BA,0.5mg/L NAA＋0.5 mg/L KT,0.5 mg/L 2,4-D＋0.5 mg/L BA或KT均可100%诱导愈伤组织。     

Effect of inorganic phosphatic fertilizers on the efficacy of an arbuscular mycorrhiza fungus against a root-knot nematode on pyrethrum

Effects of triple super phosphate (TSP) and single super phosphate (SSP) fertilizers on efficacy of a Glomus sp. (isolate KS 14) against Meloidogyne hapla were determined. The fertilizers were applied at 150 and 300 kg ha -1 at the time of fungus inoculation. Two months later, plants were inoculated with the nematodes. Plant growth and nematode disease parameters were determined 2 months after nematode inoculation. The fertilizers at both levels improved plant growth in all treatments. In general, the fungus improved plant growth on its own or in the presence of nematodes, but not in the presence of fertilizers. Both fertilizers at both levels were more effective in improving plant growth than the fungus. The fungus showed sensitivity to inorganic P fertilizers in that the fertilizers significantly reduced fungal root colonization and its pyrethrum growth stimulative effects. The fungus suppressed nematode disease severity unlike the fertilizers. The suppressive effects of the fungus on the nematodes were in most cases reduced by the fertilizers. The nematodes, unlike the fertilizers, did not have any significant effects on root colonization by the fungus or on its ability to improve pyrethrum growth. The presence of nematodes in fertilizer or fertilizer-fungus-treated plants, however, significantly reduced pyrethrum growth.     

培养基及培养条件对除虫菊细胞生长的影响

以MS、ER、MG-5、B5、H、1/2MS、M9、NT及White为基本培养基,分析不同类型培养基对除虫菊细胞生长的影响,并以MS为基本培养基进行接种量、培养时间、pH、碳源、蔗糖质量浓度、不同蔗糖和葡萄糖组合以及光照条件试验,探讨除虫菊细胞生长的最佳培养条件。结果表明:适合除虫菊悬浮细胞培养的培养基为MS培养基,细胞接种量为8~12g/L、培养时间为20~25d,pH为5.8,采用自然散射光,单独使用蔗糖作为碳源时,质量浓度为30~40g/L有利于除虫菊细胞的生长。以蔗糖作为碳源时,添加25%的葡萄糖,除虫菊细胞的增长量可以提高12%。