灰葡萄孢诱变菌株毒素的除草活性研究

 对灰葡萄孢BC4菌株进行紫外线诱变得到了15个诱变菌株, 经测定筛选出BC4-1、BC4-2和BC4-15等3个诱变菌株中以BC4-1菌株效果最好。试验发现，用于毒素产生的PD培养基的pH 值对产毒能力影响很大，以pH 4.0最优。用三氯甲烷、石油醚、乙酸乙酯萃取培养滤液制备BC-粗毒素，生物测定结果表明，以乙酸乙酯萃取所得粗毒素对杂草种子萌发及生长抑制作用最强。通过柱层析法和HPLC法分离和纯化除草活性组分,得到1个在271 nm有最大UV吸收的化合物,该组分在100 mg·L-1浓度下对马唐的生长具有强烈的抑制作用，在50 mg·L-1浓度下可完全抑制马唐和反枝苋种子的萌发。     

坪草腐霉枯萎病菌(Pythium aphanidermatum)的生物学特性及诱变菌株毒素的除草活性研究

为了明确坪草腐霉枯萎病菌PA1菌株的生物学特性及其诱变菌株所产生毒素的除草活性,对PA1菌株的生长适度、保存条件及孢子囊和藏卵器的产生条件进行了研究,测定结果发现,PA1菌株菌丝生长的最适温度为34℃,菌种保存的适宜温度为10℃～15℃;20℃条件下,在CMA培养基和燕麦粉液体培养基中可以大量产生藏卵器和卵孢子;5℃～15℃条件下,可以产生孢子囊。利用紫外线对PA1菌株的菌丝进行紫外诱变,得到了18株诱变菌株(PAM 1～18)。通过生长速率测得,PAM1菌株的生长速率最快,诱变菌株所得粗毒素对马唐和反枝苋的生长抑制作用结果表明,以PAM1的除草活性最高。对PAM1诱变菌株进行了发酵试验,在72 h的发酵过程中,发酵液的pH值逐渐降低;用发酵液制备所得粗毒素对马唐、反枝苋具有很好的除草活性。     

链格孢菌Alternaria augustiouoidea突变菌株毒素的除草活性研究

通过对链格孢菌Alternaria augustiouoidea菌株AAEC05紫外线诱变得到的8个诱变菌株进行除草剂活性测定,筛选出的AAEC05—3、AAEC05—5、AAEC05—8和AAEC05-2等4个诱变菌株具有较强的除草剂活性,其中AAEC05—3和AAEC05—5菌株效果最好。研究表明,pH值对菌株产毒能力影响很大,以pH5．0最佳。用石油醚、三氯乙烷、乙酸乙酯萃取培养滤液制备粗毒素。生物测定结果表明,以乙酸乙酯萃取所得粗毒素对稗草种子萌发及生长抑制作用最强。     

坪草腐霉病菌毒素产生除草活性物质的条件优化

从多年生黑麦草上分离得到了5株腐霉菌(编号依次为PA1、PA2、PA3、PA4、PA5),通过鉴定,PA1和PA5菌株为瓜果腐霉菌(Pythiumaphanidermatum)。将所得5株菌株分别在PD培养基、PS培养基、玉米粉培养基、改良Fries培养基、Czapek-Dox培养基和Richard培养基中进行培养,所得培养滤液、粗毒素对马唐和反枝苋的除草生物活性进行了测定。结果表明,在PD培养基中所产生的毒素除草生物活性最强,在供试的5株菌株中以PA1菌株所产生的毒素除草活性最强。PA1菌株在PD培养基中培养所得粗毒素对马唐、反枝苋、虎尾草、金色狗尾草、野燕麦、稗草、藜7种杂草的生长有明显的抑制作用;对玉米、小麦有轻微药害,而对大豆安全。试验发现,PA1菌株产毒的适宜pH值为7.0,以培养5d的毒素除草活性最强;在100~150r/min条件下,振荡培养所得粗毒素的除草活性要明显高于静止培养。     

瓜果腐霉除草活性成分的分离鉴定

 【目的】为了明确瓜果腐霉在液体培养基中所产生粗毒素的具有除草活性成分的组成及结构,本研究对具有除草活性毒素成分进行了分离纯化和结构鉴定。【方法】瓜果腐霉培养滤液分别用乙酸乙酯、石油醚、三氯甲烷等不同极性溶剂萃取制备粗毒素,用薄层层析法对粗毒素进行分离,再用高效液相色谱分离制备得到除草活性成分,通过核磁共振谱和红外光谱对其进行结构解析。【结果】用乙酸乙酯萃取得到的粗毒素活性最高;以Rf值为0.19的物质除草活性最强,对马唐的生长抑制作用达到5级;通过化学信息分析表明该成分为邻苯二甲酸二甲酯。【结论】邻苯二甲酸二甲酯是瓜果腐霉在液体培养过程中所产生的组分之一,具有除草活性。     

Isolation and Structural Indentification of Herbicidal Toxin Fractions Produced by Pythium aphanidermatum

In order to understand the compsition and structure of herbicidal component of Pythium aphanidermatum,the isolation and structural indentification were researched.The culture filtrate was extracted by ethyl acetate,petroleum,and chloroform with the same volume respectively and the activity of the crude toxin was bioassayed.The toxin was separated by using the method of thin layer chromatography（TLC）,then the main fraction was separated by HPLC,and the structure was analyzed by the sepctrum of IR,13C-NMR and 1HNMR.The results showed that the ethyl acetate extracts had the strongest herbicidal activity.Using the method of TLC,the bioassay results showed that the extracts with Rf 0.19 had the strongest effect on weeds and the inhibition to Digitaria sanguinalis and Amaranthus retroflexus reached five levels,and the component was proved to be dimethyl o-phthalate from the spectrum of IR,13C-NMR and 1HNMR,which was one of the components from the toxin,and it had herbicidal activity.     

玉米弯孢叶斑病菌毒素除草活性的研究

以杂草种子萌发和幼苗生长受阻为指标,测定了玉米弯孢叶斑病菌毒素的除草活性.结果表明:毒素对马唐种子的萌发有明显的抑制作用,抑制率可达100%,但对稗草、狗尾草种子萌发的抑制作用较小.在供试植物出苗3 d后喷施毒素,发现对马唐幼苗有致萎活性,但对出苗7 d的幼苗没有作用;对稗草、狗尾草幼苗无毒杀作用.安全性试验结果表明:...     

外来入侵植物黄顶菊的化感作用初步研究

为明确黄顶菊对其他植物的化感作用,利用黄顶菊茎叶的不同提取物对几种植物的生长影响进行了测定。结果表明,黄顶菊茎叶水提物对玉米、小麦、棉花、大豆、花生、马唐和反枝苋都表现出了不同程度的抑制作用,其中以对棉花的化感效应最强,在其浓度为0.2 g/mL时,对根长和茎长的化感指数分别为-0.85和-0.88,而该水提物对水稻的生长则表现为促进作用。黄顶菊茎叶的石油醚、氯仿、乙酸乙酯、丙酮和乙醇的提取物,对几种植物的化感效应要高于水提物,其中以丙酮提取物的化感效应最强。利用重结晶法从黄顶菊茎叶的丙酮提取物中得到了一个具有除草活性的物质,该物质的熔点为192.5℃~193.5℃,最大吸收波长为220 nm,初步判断该化合物是一种碱性有机物,该物质在浓度为1000,500,100,50 mg/L时,对马唐,反枝苋生长均有抑制作用。     

An ABAGS-Like Metabolite of Botrytis cinerea Isolate BC4 and Its Inhibitory Activity to Seed Germination of Weeds

Aimed at finding out natural compounds to kill weeds, a plant pathogenic fungus, Botrytis cinerea isolate BC4, was chosen as a source. A significantly polar metabolite, which was different in chromatographic behavior from ABAGE-like metabolite, was isolated from cultural filtrate of the fungus by column chromatography on silica gel, preparative LC, TLC and HPLC. The structure of the metabolite was determined by HPLC-ESI MS, g.l.c, IR, ^1H NMR and hydrolysis. The results showed that this metabolite was quite similar with ABAGS. The bioassay showed the metabolite had inhibition to seed germination of both broadleaf weeds [Amaranthus retroflerus L. and Chenopodium album L.] and gramineae weeds [Digitaria sanguinalis L. Scop and Echinochloa crusgalii L. Beauv]. It also had inhibitory activity to the seedling growth of broadleaf weeds. The bioassay, using Amaranthus retroflexus L. as an indicator, showed that the lowest concentration of the metabolite to inhibit root＋sprout growth of A. retroflexus was 0.6 μM, and the concentration for 50% inhibition was 1.3μM.     

Isolation and Structural Identification of Herbicidal Active Substance from Root of Flaveria bident （L.） Kuntze

In order to understand the composition and structure of herbicidal active substance from the root of Flaveria bidentis （L.） Kuntze, the isolation and structural identification were researched in this paper. The crude extract from the root ofF. bidentis （L.） Kuntze was extracted by petroleum ether, ethyl acetate, and water saturation of n-butyl alcohol, respectively, and the extraction fluid was separated by using the method of TLC, then the main fraction was separated by HPLC, and the structure of the herbicidal active substance was analyzed by LC-MS, elemental analysis and ~H-NMR. The results showed that the petroleum extraction had the strongest herbicidal activity, and the purple blue stripe separated by TLC had the strongest effect on Digitaria sanguinalis. The herbicidal active substance was identified as ct-terthienyl according to the data of LC-MS, elemental analysis and 1H-NMR.     

灰葡萄孢BC7-3菌株固体发酵条件的优化

 【目的】探讨灰葡萄孢BC7-3菌株固体发酵的基本条件以提高其除草活性物质的产量。【方法】通过正交试验设计确定最优化的培养基组合,并结合生长抑制法测定外加碳源、氮源等因素对除草活性物质产生的影响,以确定最佳的发酵条件。【结果】确定了小米5 g、高粱5 g、麦麸5 g、玉米秸秆2.5 g为最佳复合培养基质;明确了该菌株在加入1%硝酸铵、1%蔗糖的培养基中,20℃黑暗条件下,接种量8%、含水量80%、静置培养15 d,得到的除草活性物质活性最强。【结论】固体发酵适合于灰葡萄孢代谢产物中除草活性物质的产生。     

几种藜科杂草化感作用的初步测定

[目的]研究藜科杂草提取物的除草、抑菌功能。[方法]以反枝苋为供试杂草,以黄瓜枯萎病菌、苹果腐烂病菌和小麦纹枯病菌为供试菌种,研究藜科杂草猪毛菜、灰藜、小藜、绿藜、地肤的茎叶提取物对杂草和病菌的抑制作用。[结果]5种杂草的茎叶提取物对反枝苋种子萌发及幼苗生长都有一定的抑制作用,其中,地肤茎叶提取物的抑制活性最高,当其浸膏浓度为0.10 g/ml时,对反枝苋茎生长的抑制率达100%,对种子萌发和根生长的抑制率超过90%;用石油醚、乙酸乙酯、甲醇对地肤茎叶提取物萃取分离后发现,石油醚萃取部分的除草效果较好,而甲醇萃取部分的抑菌活性较高。[结论]藜科杂草提取物具有一定的除草和抑菌功能。     

Isolation and identification of Serratia marcescens Ha1 and herbicidal activity of Ha1 ‘pesta’ granular formulation

A total of 479 bacterial strains were isolated from brine(Bohai, Qinhuangdao City, Hebei Province, China). Bioassay results indicated that 4 strains named Ha1, Ha17, Ha38, and Ha384 had herbicidal activity. And strain Ha1 had the highest effective herbicidal activity. As a result, this study aims to identify strain Ha1, characterize its physiological and biological activities, evaluate the herbicidal activity of its metabolites, and develop a ‘pesta' formulation and assess its effectiveness on Digitaria sanguinalis. Ha1 was identified as Serratia marcescens based on 16 S r DNA sequencing. This strain has a flagellum, a diameter of 0.5 to 0.8 μm, and a length of 0.9 to 2.0 μm. The indole test shows positive results, and the catalase enzyme exhibits strong positive reactions. Results further showed that the inhibitory concentration(IC50) of the crude extracts to D. sanguinalis radicula and coleoptile were 3.332 and 2.828 mg m L–1, respectively. Both the suppression of D. sanguinalis and the cell viability of the Ha1 formulation in ‘pesta' were higher when stored at 4°C than at(25±2)°C. These results indicated that S. marcescens Ha1 can potentially be used as a biocontrol agent against D. sanguinalis.     

中国粗榧生物碱的除草活性

【目的】明确中国粗榧(Cephalotaxus sinensis)的除草活性成分,为进一步深入研究中国粗榧的除草作用打下基础。【方法】采用种子萌发法评价中国粗榧乙醇提取物、中国粗榧总生物碱及从中分离得到的8种生物碱(桥氧三尖杉碱、11-羟基三尖杉碱、贡山三尖杉碱A、异三尖杉碱、cephalotaxineβ-N-oxide、4-羟基三尖杉碱、台湾三尖杉碱和三尖杉碱)对红三叶(Trifolium pratense)、反枝苋(Amaranthus retroflexus)、黑麦草(Lolium perenne)及高丹草(Sorghum sudanense)4种杂草种子幼根和幼芽的生长抑制作用;采用盆栽法测定中国粗榧乙醇提取物、中国粗榧总生物碱及各生物碱的鲜重抑制率。【结果】种子萌发试验表明,中国粗榧提取物、中国粗榧总生物碱及桥氧三尖杉碱、11-羟基三尖杉碱、三尖杉碱和cephalotaxineβ-N-oxide对红三叶种子具有较强的抑制作用,对幼根的有效中浓度(EC_(50))分别为634.35、690.47、69.47、71.21、174.11和243.12 mg·L~(-1),对幼芽的EC_(50)分别为411.79、413.11、68.52、139.25、237.72和413.62 mg·L~(-1);中国粗榧提取物、中国粗榧总生物碱及桥氧三尖杉碱、11-羟基三尖杉碱、三尖杉碱和cephalotaxineβ-N-oxide对反枝苋种子具有较强的抑制作用,对幼根的EC_(50)分别为176.32、29.69、21.01、48.08、199.57和90.74 mg·L~(-1),对幼芽的EC_(50)分别为257.69、46.20、25.51、47.85、65.08和66.34 mg·L~(-1);仅中国粗榧提取物、中国粗榧总生物碱及桥氧三尖杉碱对高丹草种子具有抑制作用,对幼根的EC_(50)分别为349.54、254.27和84.71 mg·L~(-1),对幼芽的EC_(50)分别为556.50、168.66和154.34 mg·L~(-1);仅中国粗榧提取物、cephalotaxineβ-N-oxide及桥氧三尖杉碱对黑麦草种子具有抑制作用,对幼根的EC_(50)分别为214.40、187.89和26.52 mg·L~(-1),对幼芽的EC_(50)分别为695.58、290.15和122.26 mg·L~(-1);盆栽试验表明,中国粗榧提取物、总生物碱及3种生物碱(桥氧三尖杉碱、11-羟基三尖杉碱、三尖杉碱)对双子叶杂草红三叶和反枝苋表现出了一定的苗前除草作用,其中桥氧三尖杉碱的活性最高,以1 000 mg·L~(-1)浓度进行土壤处理后,14 d的鲜重抑制率分别为78.89%和81.11%,但对禾本科的高丹草和黑麦草的鲜重抑制率较低,均在25%以下;茎叶喷雾处理显示,5种药剂对双子叶杂草红三叶和反枝苋的生长表现出一定的抑制作用,但抑制率均在30%以下,而对2种单子叶杂草基本无效果。【结论】中国粗榧生物碱对双子叶杂草具有较好的除草活性,其主要活性成分为桥氧三尖杉碱,且主要作用方式为抑制幼芽(根)的生长,具有进一步研究及开发潜力。     

Isolation,Identification, and Herbicidal Activity of Metabolites Produced by Pseudomonas aeruginosa CB-4

CB-4, a bacterial strain with highly effective herbicidal activity, was isolated from infected corn leaves. Through morphology, physiological and biochemical tests, and 16 S ribosomal DNA gene sequencing methods, CB-4 was identified as Pseudomonas aeruginosa. We conducted activity-evaluation experiments in the laboratory to assess the herbicidal potential of metabolites produced by strain CB-4. Crude extracts of strain CB-4 have high inhibition activity on Digitaria sanguinalis. In general, the root and shoot growth parameters of D. sanguinalis were significantly reduced by metabolites of strain CB-4. The IC50 of the culture filtrate extracts for the radicula and coleoptile of D. sanguinalis were 0.299 and 0.210 mg mL-1, respectively. Component 2 of the herbicidal activity of the crude toxin from strain CB-4 was successfully purified for the first time by using high-speed counter current chromatography with a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water（4：5：4：5, v/v） and high-performance liquid chromatography. We concluded that the metabolites of strain CB-4 have the potential to be developed as a microbe-based herbicide.     

小飞蓬对三种杂草种子萌发和幼苗生长的化感作用

以稗草[Echinochloa crusgalli (L.) Beauv.]、鬼针草(Bidens pilosa L.)、含羞草(Mimosa pudica L.)3种杂草种子为受体,以小飞蓬[Conyza canadensis (L.) Cronq.]全株为供体,采用培养皿滤纸培养法研究小飞蓬水提取液的乙酸乙酯、正丁醇和水萃取物对受体植物种子萌发和幼苗生长的化感作用.结果表明,小飞蓬的乙酸乙酯萃取物强烈抑制稗草和鬼针草的种子萌发和幼苗生长,且抑制效应随萃取物浓度的升高而提高,高浓度的乙酸乙酯萃取物对含羞草的种子萌发和幼苗生长抑制作用明显.乙酸乙酯萃取物浓度为0.5 mg/mL时,其对3种杂草幼苗的根长、茎长和鲜重的抑制作用与对照组比较就有显著差异.乙酸乙酯萃取物浓度为2.0 mg/mL时,其对稗草和鬼针草根长的化感效应指数(RI)值均为-1.00,对茎长的RI值分别为-0.97和-0.78;二者种子的萌发率平均值分别为3.3％和2.2％.小飞蓬的正丁醇萃取物抑制3种杂草的种子萌发和幼苗生长,但比乙酸乙酯萃取物的抑制作用弱.高浓度小飞蓬水萃取物强烈促进3种杂草的幼苗生长.说明小飞蓬水提取液中的除草活性物质可能存在于乙酸乙酯和正丁醇萃取物中.     

多孢木霉HZ-31菌株活性物质的初步分离及除草活性研究

为明确多孢木霉HZ-31菌株的除草活性物质,对其活性成分进行逐步分离。采用种子萌发法和离体叶片接种法分离最佳活性组分。结果表明,HZ-31菌株发酵滤液活性高于发酵液,发酵滤液对野燕麦和油菜种子萌发抑制率分别为80.00%和91.67%。4种有机溶剂萃取物对7种杂草叶片的致病效果由强到弱表现为:正丁醇相乙酸乙酯相石油醚相氯仿相。4种有机溶剂萃取粗提物在5 mg/mL浓度下对野燕麦和油菜的种子萌发均有强烈的抑制作用,除乙酸乙酯外,其余处理的发芽抑制率为100%。3 mg/mL浓度下正丁醇粗提取物能完全抑制野燕麦和油菜种子的萌发。因此,粗提物活性测定以离体叶片和种子萌发结果为依据,检测HZ-31菌株活性物质最佳有机相,最终确定最佳活性组分在正丁醇相中。     

叉枝鸦不同溶剂萃取物对反枝苋种子萌发及幼苗生长的影响

为了确定沙漠野生植物叉枝鸦葱拟化感物质的有效部位,为分离纯化拟化感先导化合物奠定基础,试验研究了叉枝鸦葱醇提物的四种不同极性溶剂萃取物对反枝苋种子萌发、幼苗生长发育的影响.采用培养皿法,在人工气候箱模拟条件下,测定各萃取物对反枝苋种子萌发、幼苗生长发育的影响.结果表明各萃取物对反枝苋种子萌发、幼苗生长发育均有不同程度的...     

硬毛刺苞菊不同器官的除草活性研究

利用琼脂混粉法测定了硬毛刺苞菊根、茎、叶和种子粉末对4种受体植物的除草活性。在10g／L的粉末添加浓度下,4种植物器官均对生菜、小麦、反枝苋和稗草幼苗的生长产生了明显的抑制作用,且对胚根（或幼根）生长的抑制效果明显高于对胚轴（或胚芽）的抑制,其中以叶片的抑制效果最为明显。4种器官中除叶片对反枝苋种子具有明显的推迟发芽作用外,对生菜、稗草和小麦种子的发芽影响均不显著。     

飞机草链格孢毒素的培养条件、分离及活性测定

[目的]对链格孢菌株LGB 100401的产毒培养条件及毒素的除草活性进行评估,为飞机草的生物防治提供理论依据.[方法]以从海南田间染病的飞机草上分离到的链格孢菌LGB 100401菌株为材料,采用以生物测定为导向的乙酸乙酯萃取和硅胶柱层析等方法对LGB 100401菌株所产毒素进行分离纯化及产毒条件研究,并采用离体叶片针刺接种法测定38种植物对LGB 100401菌株所产毒素的敏感性.[结果]LGB 100401菌株可产生毒素并导致飞机草叶片枯死,最适产毒条件为25℃、pH 4~6、光暗交替培养15d.LGB 100401菌株分泌的毒素对供试38植物具有选择毒性,其中,供试杂草对链格孢粗毒素不敏感(NS)的有17种、稍敏感(LS)4种、敏感(MS)7种、极敏感(SS)4种,表现为极敏感的杂草为飞机草、马唐、羽芒菊和赛葵;供试的6种作物中只有水稻表现为敏感(MS),其他5种作物不敏感或表现轻微症状.[结论]飞机草链格孢毒素对飞机草具有较高的抑制活性,具有较高的生防潜力.