植物源农药的筛选及补骨脂抑菌活性

以水稻稻瘟病菌、辣椒疫霉病菌、黄瓜炭疽病菌为靶标菌，通过孢子萌发试验对12种植物提取物的抑菌活性进行粗筛。结果表明，植物粗提物在100mg／L质量浓度下，补骨脂提取物对水稻稻瘟病菌和辣椒疫霉病菌孢子萌发的抑制率均为100％，虎杖和黄柏提取物对水稻稻瘟病菌孢子萌发的抑制率均为100％。然后，采用菌丝生长速率法将补骨脂提取物对11种植物病原菌的抑菌活性进行了测定，结果表明，补骨脂粗提物对苹果腐烂等11种植物病原菌均具有抑制作用，其中，对苹果腐烂病菌、黄瓜炭疽病菌、小麦赤霉病菌、水稻稻瘟病菌的EC50分别为17．669、73．136、77．294、32．141mg／L。     

枯茗酸药效分析及对辣椒疫霉病菌的抑制

为探究植物性提取物枯茗酸活体对辣椒疫霉病菌、番茄灰霉病菌、黄瓜白粉病菌和小麦白粉病菌的生物性抑制作用,以及对辣椒疫霉病菌的药效,选取了常规农药药剂速克灵、甲霜灵和三唑酮进行对比实验,采用组织法和盆栽药效实验。结果表明,枯茗酸对辣椒疫霉病菌、番茄灰霉病菌和黄瓜白粉病菌具有良好的生物活性抑制作用,对接种的辣椒疫霉病菌果实无明显效果防治和治疗效果。通过光学显微镜和电子显微镜观察表明,枯茗酸对辣椒疫霉病菌生物活性及形态具有较大的影响。同时能有效改变辣椒疫霉病菌细胞膜通透性,且枯茗酸浓度越高,短时间内改变效果越明显,最终趋于稳定。     

天麻茎秆化学成分抑菌活性初步研究

采取65%乙醇、甲醇、四氯化碳3种有机溶剂作为提取溶剂,分别对天麻地上茎秆部分进行化学成分提取。就3种溶剂的提取浸膏对8种植物病原真菌的抑菌活性进行了初步研究。结果表明,在100μg/m L浓度下,天麻茎秆甲醇提取浸膏对对辣椒疫霉病菌、西瓜炭疽病菌表现出较好的抑菌活性。     

2-取代-4-氯-5-芳基-2H-1,2,3-三唑类化合物的合成及其生物活性

为发现杀菌活性高、抑菌谱广的新化合物，以芳醛、硝基甲烷及叠氮化钠为起始原料，经环化、氯化、烃化反应合成了15个2-取代-4-氯-5-芳基-2H-1,2,3-三唑类新化合物，目标物的分子结构经核磁共振谱、质谱和元素分析进行了确证。采用菌丝生长速率测定法，在25 mg/L的测试浓度下，目标化合物对小麦赤霉病菌、辣椒疫霉病菌、烟草赤星病菌、黄瓜灰霉病菌、水稻纹枯病菌及油菜菌核病菌6种作物病菌进行了离体抑菌活性试验。初步的抑菌活性测试结果表明：化合物4d对小麦赤霉病菌、黄瓜灰霉病菌及油菜菌核病菌的抑制率分别为70.4%、74.1%和72.9%，化合物4k对黄瓜灰霉病菌及油菜菌核病菌的抑制率分别为87.0%及84.7%。4d对辣椒疫霉病菌的抑制率为61.4%，高于商品化品种苯醚甲环唑的42.5%。     

2-取代-4-氯-5-芳基-2H-1,2,3-三唑类化合物的合成及生物活性

以芳醛、硝基甲烷及叠氮化钠为起始原料,经环化、氯化、烃化反应,以收率53%～94%合成了15个2-取代-4-氯-5-芳基-2H-1,2,3-三唑类化合物(Ⅳa～o),经核磁共振波谱、质谱和元素分析对目标化合物的结构进行确证。采用菌丝生长速率测定法,在质量浓度25mg/L下,目标化合物对小麦赤霉病菌、辣椒疫霉病菌、烟草赤星病菌、黄瓜灰霉病菌、水稻纹枯病菌及油菜菌核病菌6种作物病菌进行离体抑菌活性实验。初步的抑菌活性测试结果表明:化合物Ⅳd对小麦赤霉病菌、黄瓜灰霉病菌及油菜菌核病菌的抑制率分别为70.4%、74.1%和72.9%,化合物Ⅳk对黄瓜灰霉病菌及油菜菌核病菌的抑制率分别为87.0%及84.7%。Ⅳd对辣椒疫霉病菌的抑制率为61.4%,高于商品化品种苯醚甲环唑的42.5%。     

拮抗假单胞菌SU8对几种植物病原真菌的抑制作用

[目的]评价拮抗假单胞菌SU8的生防潜力,开发绿色农药。[方法]采用平板对峙法和打孔法研究拮抗假单胞菌SU8、发酵滤液及其乙酸乙酯提取物的抑菌活性。[结果]假单胞菌SU8对稻瘟病菌的抑制效果最好,抑菌带宽度达4.53 cm,辣椒炭疽病菌次之,其余从强到弱依次为烟草赤星病菌、水稻纹枯病菌和小麦赤霉病菌;发酵滤液对水稻纹枯病菌、稻瘟病菌、小麦赤霉病菌、辣椒炭疽病菌、烟草赤星病菌抑菌活性较弱;乙酸乙酯提取物对烟草赤星病菌的抑制效果最好,抑菌带宽度为3.92 cm,对水稻纹枯病的抑菌带宽度为2.34 cm,对其他植物病原菌的抑菌效果从大到小依次为稻瘟病菌、辣椒炭疽病菌和小麦赤霉病菌。[结论]拮抗假单胞菌SU8具有可开发仿生农药的前景。     

新杀菌剂氟肟菌酯对几种作物病原菌的生物活性研究

采用含毒介质法和活体盆栽法对具有自主知识产权的新甲氧基丙烯酸酯类杀菌剂品种氟肟菌酯(试验代号HNPC-A4008)进行了生物活性研究。结果表明,氟肟菌酯对稻瘟病菌、水稻纹枯病菌、水稻恶苗病菌、小麦赤霉病菌、玉米小斑病菌和苹果轮纹病菌的菌丝生长具有明显的抑制作用,其EC50值分别为4.3652×10-3,8.985 6×10-2,1.752 6×10-1,8.830 0×10-1,2.261 5×10-1,3.031 8×10-1 g/mL,但对辣椒疫霉病菌菌丝生长的抑菌活性作用很弱,其EC50值为8.7039×101 g/mL。氟肟菌酯对黄瓜白粉病、小麦白粉病和水稻稻瘟病具有较好的保护和治疗作用,但内吸传导作用较弱。     

落地生根叶乙醇提取物的抑真菌作用

采用菌丝生长速率法研究了落地生根叶乙醇提取物对9种植物病原真菌的抑制作用,同时采用菌丝生长速率和孢子萌发2种方法测定其对番茄早疫病菌的抑菌活性.结果表明:在200 g/L的质量浓度下,对9种植物病原真菌均有一定的抑制作用,抑制率达50%以上,其中对番茄早疫病菌抑制作用最强,抑制率达93.80%,对其孢子萌发的抑菌活性高于对其菌丝生长的抑菌活性,EC50值分别为38.70、28.97 g/L.     

穿破石抑菌活性初步研究

采用菌丝生长速率法测定了穿破石不同部位甲醇提取物对5种植物病原真菌的抑菌活性.结果表明:穿破石根提取物对梨锈病菌、稻瘟病菌、水稻纹枯病菌以及玉米炭疽病菌有很高的抑菌活性,质量浓度为10 g/L时,抑菌率分别为95.51%、99.39%、100.00%、86.11%;有效中浓度(EC50)分别为0.8031、0.9969、0.9812、0.9304 g/L.对柿角斑病菌的活性较低,质量浓度为10 g,L时,抑菌率为66.72%,EC50值为4.6539 g/L.茎叶提取物对上述5种病原菌的抑菌活性较低.采用固-液萃取法对穿破石抑菌活性成分进行了初步分离,结合活性跟踪,发现穿破石抑菌活性成分主要存在于乙酸乙酯萃取层中.     

海芋甲醇提取物的抑真菌作用

采用生长速率法测定了海芋的不同部分甲醇提取物对水稻纹枯病菌等15种植物病原真菌的生物活性。结果表明：海芋叶、茎和叶柄的甲醇提取物对荔枝霜疫霉病菌、稻瘟病菌和白菜黑斑病菌等有一定的活性；在10mg／mL的浓度下，海芋叶、茎和叶柄的甲醇提取物对水稻纹枯病菌菌丝生长的抑制率分别为53．45％、43．15％和41．14％；海芋叶甲醇提取物对水稻纹枯病菌的EC50值为8．52mg／mL。海芋叶甲醇提取物的石油醚、氯仿、乙酸乙酯和正丁醇萃取组分对水稻纹枯病菌的活性研究表明，氯仿层的活性最高，抑制率为89．12％。海芋叶甲醇提取物的氯仿萃取物对水稻纹枯病菌的EC50值为2．13mg／mL.     

Biological activity and tentative identification of flavonoid components in velvetleaf (Abutilon theophrasti Medik.) seed coats

The biological activity of aqueous extracts of velvetleaf (Abutilon theophrasti Medik.) seed coats and their flavonoid components against three plant species and five soil fungi was investigated. Aqueous extracts slightly inhibited germination and significantly inhibited radicle growth of all plant species tested. Fungal growth was inhibited or not affected, depending on species, by aqueous extracts. The aqueous extracts were extracted into methanol and separated using paper chromatography for identification of compounds responsible for inhibition of seedling and fungal growth. Six flavonoid compounds were isolated and tentatively identified as delphinidin, cyanidin, quercetin, myricetin, (+)-catechin, and (–)-epicatechin. Bioassays revealed that the flavonoid compounds significantly inhibited germination and radicle growth of all test species at a concentration of 1.0 mM. Individual flavonoids had variable effects on fungi but appeared to inhibit growth and sporulation of potential seed-decomposing fungi rather than beneficial fungi. These results indicate that the flavonoid complement of velvetleaf seed coats may function in a dual defensive role against competing seedlings and seed-attacking fungi.Journal article No. 9878 of the Missouri Agricultural Experiment Station.     

The Antifungal Compound Totarol of <Emphasis Type="Italic">Thujopsis dolabrata</Emphasis> var. <Emphasis Type="Italic">hondai</Emphasis> Seeds Selects for Fungi on Seedling Root Surfaces

Hinoki-asunaro (Thujopsis dolabrata Sieb. et Zucc. var. hondai Makino) is a tree endemic in Japan whose seeds produce several terpenoids. We hypothesized that antifungal compounds in seeds might select for fungi on the root surfaces of T. dolabrata var. hondai seedlings. We examined seed and soil fungi, their sensitivity to methanol extracts of the seeds, the fungi on root surfaces of seedlings grown in Kanuma pumice (a model mineral soil) and nursery soil, and the frequency at which each fungus was detected on the seedling root surface. We calculated correlation coefficients between fungal detection frequency on root surfaces and fungal sensitivity to seed extracts. We also isolated from the seeds the antifungal compound totarol that selected for fungi on root surfaces. Species of Alternaria, Cladosporium, Pestalotiopsis, and Phomopsis were the most frequently isolated fungi from seeds. Mortierella and Mucor were the dominant fungi isolated from Kanuma pumice, whereas Umbelopsis and Trichoderma were the main fungi isolated from nursery soil. Alternaria, Cladosporium, Mortierella, Pestalotiopsis, and Phomopsis were the dominant fungi isolated from root surfaces of seedlings grown in Kanuma pumice, and Alternaria, Cladosporium, Pestalotiopsis, Phomopsis, and Trichoderma were the main root-surface fungi isolated from seedlings grown in nursery soil. The fungal detection frequencies on root surfaces in both soils were significantly and negatively correlated with fungal sensitivity to the seed extract. A similar correlation was found between the fungal detection frequency on root surfaces and fungal sensitivity to totarol. We conclude that totarol is one factor that selects for fungi on root surfaces of T. dolabrata var. hondai in the early growth stage.     

均匀设计超声循环提取印楝活性物质的研究

使用超声循环提取机进行了对印楝种仁中印楝活性成分的萃取工艺研究,以印楝素A质量为检测指标,采用均匀设计–偏最小二乘法回归分析优化萃取工艺的甲醇加入量、超声功率、提取时间和循环转速4个因子,确定最佳提取工艺条件为:甲醇加入量为5L,超声功率为1500W,提取时间40min,循环转速1800r/min。此时,500g印楝种仁粉的萃取物中印楝素A的理论产量为3.06g。并对该技术应用于印楝种仁中印楝活性成分提取的产业化前景和可行性进行了探讨。     

厚果鸡血藤提取物对两种同翅目害虫的生物活性

测定了厚果鸡血藤种子和根提取物对褐飞虱和桃蚜两种同翅目害虫的生物活性,结果表明,它们对这两种害虫有很高的触杀活性,对桃蚜有一定的胃毒活性。用不同溶剂提取时,三氯甲烷提取物的活性明显高于甲醇提取物的活性。用相同溶剂提取时,种子提取物的活性比根提取物活性高。对褐飞虱、桃蚜的触杀活性及对桃蚜的胃毒活性均以种子三氯甲烷提取物最高,种子三氯甲烷提取物对褐飞虱、桃蚜的接触LD50值分别为0.25、0.03g/头,对桃蚜的胃毒LC50值为1342mg/L。四种提取物对两种害虫的毒力顺序为:种子三氯甲烷提取物>根三氯甲烷提取物>种子甲醇提取物>根甲醇提取物。     

Casuarina cunninghamiana Tissue Extracts Stimulate the Growth of Frankia and Differentially Alter the Growth of Other Soil Microorganisms

Aqueous extracts of host plant Casuarina cunninghamiana tissue altered the in vitro growth of its diazotrophic microsymbiont Frankia and a selection of other soil microorganisms. The growth of actinomycetous Frankia strains, 55005. AvcI1, CesI5, CjI82 001, and Cj was stimulated by aqueous extracts of C. cunninghamiana tissue. Green cladodes (photosynthetic branches), unsuberized roots, and suberized roots were more stimulatory than dry cladodes and seed tissue. Aqueous extracts of green cladodes of C. cunninghamiana most stimulated the growth of Casuarina-derived Frankia strains CjI82 001 and 55005. The growth of isolates of soil bacteria Bradyrhizobium japonicum, Arthrobacter globiformis and Bacillus subtillis and of the soil fungi Penicillium oxalicum and Arthroderma cookiellum was either inhibited or not affected by cladode extracts. Cladode extracts stimulated the growth of the actinomycete Streptomyces albus and the fungus Rhizopus homothallicus. The magnitude (as great as 100%) of the increase in growth caused by tissue extracts for the Casuarina-derived Frankia strains relative to other soil microbes suggests a host-specific enhancement of the microsymbiont.     

万寿菊粗提物的抑菌作用初探

以万寿菊根粗提物作为供试药剂，对黄芪枯萎病菌和番茄灰霉病菌等6种植物病原真菌进行了抑菌试验。结果表明，万寿菊根粗提物对病菌的孢子萌发、菌丝生长速率和菌丝生长量均有不同程度的抑制作用。其中，对蕃茄叶霉病菌的抑制效果最好，达80％以上。     

Antifungal Xanthones from Calophyllum brasiliensis Heartwood

The heartwood of the tropical tree Calophyllum brasiliensis is known to be highly resistant to fungi and termites. To determine whether resistance to wood-rotting fungi could be caused by bioactive secondary metabolites, a chemical and biological study was carried out. Hexane, acetone, methanol, and water extracts were prepared. The yield of the extracts ranged from 0.04% (hexane) to 4.81% (acetone). Methanol, acetone, and water extracts (5 mg/ml = 0.5%) inhibited the mycelial growth of the brown rot fungus Postia placenta by 83%, 59%, and 21%, respectively. Chromatographic separation of the acetone and methanol extracts afforded five prenylated xanthones: 6-desoxyjacareubin (I), 1,5-dihydroxy-2-(3,3-dimethylallyl)-3-methoxy-xanthone (II), jacareubin (III) and 1,3,5-trihydroxy-2-(3,3-dimethylallyl)-xanthone (IV) and 1,3,5,6-tetrahydroxy-2-(3,3-dimethylallyl)-xanthone (V). Xanthones III, IV, and especially V, were the most abundant constituents of both extracts and inhibited at 0.25 mg/ml the mycelial growth of P. placenta. Inhibitory activity ranged from 55.5% (V) to 68.8% (III and IV mixture). Acetylation of xanthones did not induce a sharp change in the extent of fungistasis compared with parent compounds. The above results suggest that C. brasiliensis xanthones actually play a defensive role against wood decay fungi.     

藜芦乙醇提取物对植物病原真菌的抑菌活性研究

通过测定藜芦的乙醇提取物以及各萃取部分对植物病原真菌的抑菌活性,寻找藜芦中的农用活性物质,为其综合开发利用提供科学依据。采用菌丝生长速率法测定了藜芦球茎和根乙醇提取物对6种植物病原菌的抑制作用。试验结果表明,当供试浓度为5.0 mg/mL时,对苹果腐烂病菌(Valsa mali)、棉花枯萎病菌(Fusarium oxysporum f.sp.vasinfectum)和苹果轮纹病菌(Physalospora piricola nose)的抑菌率比较高,分别为96.4%、78.1%和74.3%。藜芦乙醇提取物的不同极性溶剂萃取物的抑菌活性较高,乙酸乙酯萃取物对苹果腐烂病菌和苹果轮纹病菌的EC50分别为0.161 mg/mL和0.551 mg/mL;正丁醇萃取物对苹果腐烂病菌和苹果轮纹病菌的EC50分别为0.190 mg/mL和0.451 mg/mL。乙酸乙酯萃取物是进一步研究的重点。     

坡柳种子提取物对菜青虫取食和生长发育的影响

研究了坡柳种子乙醇提取物对菜青虫4龄幼虫的拒食作用和生长发育的影响。结果表明,坡柳种子乙醇提取物对菜青虫4龄幼虫有显著的拒食活性,24、48h的非选择性拒食性AFC50值分别为742.14、1099.93mg/L;选择性拒食AFC50值分别为1081.15、1553.2mg/L;乙醇提取物对菜青虫4龄幼虫的生长发育抑制作用明显,随施药剂量的增加,生长抑制率增大,化蛹率降低,处理剂量为5000mg/L时,生长抑制率大于100%,化蛹率仅为13.33%。