留兰香挥发油熏蒸抑菌活性研究

为了确定留兰香挥发油对植物病原真菌的生防效果,进一步探讨其抑菌机制,以明确其在植物真菌病害防控方面的应用前景,本研究采用菌丝生长速率法测定了留兰香挥发油对番茄灰霉病菌Botrytis cinerea、小麦赤霉病菌Fusarium graminearum、水稻纹枯病菌Rhizoctonia solani和莴苣菌核病菌Sclerotinia sclerotiorum 4种植物病原真菌的熏蒸抑制作用,并利用GC-MS分析了留兰香挥发油的化学组分。结果显示,留兰香挥发油对4种供试真菌均有强烈的熏蒸抑制作用,EC_(50)均低于7.0μL/L。挥发油处理后番茄灰霉病菌菌丝畸变、表面塌陷,细胞膜被破坏、原生质泄漏,细胞质结构呈消解状,线粒体受损。通过GC-MS从留兰香挥发油中分离出30个组分,鉴定出其中24个组分,占挥发油总量的94.918%,其主要成分有L-香芹酮(57.468%)、D-柠檬烯(8.976%)等。研究表明,留兰香挥发油是理想的绿色熏蒸杀菌资源。     

紫茎泽兰挥发性成分及抑菌活性研究

采用索氏提取器及水蒸气蒸馏两种方法对采于不同时间、不同产地的紫茎泽兰Eupatorium adenophorum Spreng挥发性成分进行了提取,比较了两种方法的得油率、化学组成及其相对含量;采用GC-MS联用技术对其中的挥发性成分进行了分析。结果表明:同一种植物挥发性成分的组成及相对含量因提取方法不同而具有明显的差异,如贵州紫茎泽兰叶中的α-红没药醇用索式提取器提取和水蒸气蒸馏提取的相对含量分别为1.99%和7.55%;不同采集时间、不同产地及不同植物器官的化学组份及相对含量也具有明显差异,如姜黄烯(gurcumene)在不同紫茎泽兰叶或种子中的相对含量在0.41%~5.23%之间。初步的抑菌试验表明:紫茎泽兰挥发油提取液在浓度为3 000 mg/kg时对4种供试真菌的抑制率均大于60％,其中对番茄灰霉菌抑制作用最强,其EC50值为580.5 mg/kg。     

NYS-4菌株发酵液抑菌活性成分的分离及初步结构鉴定

NYS-4菌株是从秦岭地区土壤中分离到的一株放线菌。采用管碟法及抑制菌丝生长速率法测定了NYS-4菌株发酵液对多种病原细菌和真菌的抑菌活性。结果表明:NYS-4菌株发酵液对白菜软腐病菌 Erwinia carotovora var.、猕猴桃溃疡病菌 Kiwi ulcer disease germs 和枯草芽孢杆菌 Bacillus subtilis 3种病原细菌具有较强的抑菌活性;对西瓜枯萎病菌 Fusarium oxysporum f.sp .Niveum 、烟草赤星病菌 Alternaria alternate 、油菜菌核病菌 Sclerotinia sclerotiorum 等8种病原真菌菌丝生长亦具有较强的抑制作用。采用离子交换树脂吸附、凝胶柱层析、反相高效液相色谱等方法,结合高效液相色谱-质谱联用(HPLC-ESI-MS/MS)技术,对NYS-4菌株发酵液的活性次生代谢物进行了分离和鉴定,从中分离鉴定出14个链丝菌素(streptothticin)类化合物,其中, N -乙酰化链丝菌素A、 N -乙酰化链丝菌素B、 N -乙酰化链丝菌素B酸和链丝菌素B酸经初步鉴定为新化合物。     

10种香料植物挥发油的抑菌活性研究

为了研究香料植物的抑菌活性,为进一步开发植物源杀菌剂提供理论参考,采用生长速率法及悬滴法测定10种香料植物挥发油对茄镰孢(Fusarium solani)、链格孢(Alternaria alternata)、核盘菌[Sclerotinia sclerotiorum (Lib.) de Bary]、齐整小核菌(Sclerotium rolfsii Sacc.)、束状炭疽菌[Colletotrichum dematium( Pers.) Grove]的抑制活性.结果表明,肉桂、草果、香茅具有较强的抑菌活性,在浓度为0.5 g/L时对供试的5种植物病原菌菌丝抑制率均达100％,对茄镰孢、链格孢、束状炭疽菌的孢子萌发抑制率均高于90％.0.5 g/L浓度的香茅挥发油对5种目标菌的抑制作用达到100％,与30％苯甲·丙环唑乳油杀菌剂作用等同,且高于75％百菌清可湿性粉剂、50％多菌灵可湿性粉剂、70％甲基硫菌灵可湿性粉剂等常规杀菌剂.本研究结果表明,香茅值得进一步研究开发.     

土荆芥精油对灰茶尺蠖幼虫的熏蒸活性及对其体内两种酶活力的影响

采用皿内测定法,研究了土荆芥精油对灰茶尺蠖的熏蒸活性及对其体内2种解毒酶活性的影响。结果表明,随着土荆芥精油剂量的增加和处理时间的延长,灰茶尺蠖幼虫的死亡率也相应升高;LC₅₀随着处理时间的延长,逐渐降低;通过测定土荆芥精油对灰茶尺蠖幼虫体内解毒酶活力变化表明,其精油对灰茶尺蠖幼虫体内的乙酰胆碱酯酶呈明显的抑制作用,对羧酸酯酶呈激活后抑制的作用。     

棉籽壳中除草活性物质提取及鉴定

为了开发利用棉籽壳中的除草活性物质,分别以无水乙醇、正丁醇、石油醚和乙酸乙酯为溶剂,采用索氏提取法对棉籽壳中的活性物质进行了提取,并对各溶剂粗提物进行了除草活性测定。结果发现:用无水乙醇提取的粗提物对稗草生长的抑制活性最高,经气相色谱-质谱(GC-MS)联用分析,发现该粗提物中主要含有甘油、三环己基3-烯-6-辛酮、4-乙烯基-2-甲氧基苯酚、(邻甲基苯酚)-2-溴-2氯-乙酰酯、十四酸、十四酸乙酯、十六烷酸、辛酸异戊酯和亚油酸9种化合物。进一步的除草活性测定结果表明,亚油酸、辛酸异戊酯、4-乙烯基-2-甲氧基苯酚和(邻甲基苯酚)-2-溴-2氯-乙酰酯4种化合物对稗草表现出一定的除草活性,其中亚油酸活性最强,其IC₅₀值为14.5 mg/L。     

枯草芽孢杆菌挥发产物的杀线虫活性评价及成分鉴定

寄牛线虫Ditylenchus destructor是许多作物和蔬菜的重要病原物.本研究进行的密封皿内测定结果表明,由枯草芽孢杆菌BL02和G8产生的挥发物能够强烈地抑制D.destructor(24 h杀虫活件均达100%).经挥发物处理后,大部分线虫在1～12 h内活动逐渐减弱,24 h后完全停止活动.经固相微萃取并经气相色谱-质谱联脂技术进一步鉴定,挥发物包括烷烃、醇、酯、酮、酸、胺、肟、酚及杂环类.本研究为微生物活性挥发物的开发和利用提供了有价值的参考并预示了细菌挥发物在未来植物线虫病害生物防治方而的应用潜力.     

2-取代苯基-5-取代苯甲酰胺基-1,3,4-噻二唑的合成、抑菌活性及三维定量构效关系

以取代苯甲酸为起始原料,与氨基硫脲、三氯氧磷及取代苯甲酰氯进行缩合,制备了33个2-取代苯基-5-取代苯甲酰胺基-1,3,4-噻二唑 E ₁ ~E ₃₃ 。采用核磁共振氢谱 (1H NMR) 和高分辨质谱 (HRMS) 等对目标化合物的结构进行了确证及表征。采用菌丝生长速率法测定了目标化合物对根霉Rhizopus nigricans、青霉Penicillium glaucum、灰霉Botrytis cinerea、交链孢霉Alternaria brassicae和黑曲霉Aspergillus niger的体外抑菌活性。针对黑曲霉的抑制活性,分别利用CoMFA和CoMSIA对目标化合物进行了初步的三维定量构效关系 (3D-QSAR) 研究。结果表明,大部分化合物表现出良好的抑菌活性,在50 μg/mL下,化合物 E ₁ 、 E ₂ 和 E ₂₉ 对供试真菌的抑制率均达到80%以上,与对照药剂百菌清和多菌灵的抑菌效果相当。综合两种模型的结果,发现静电场的贡献值高于其他势场,且当苯环a的4位引入供电子基、苯环a的2位和6位以及苯环b上引入吸电子基时,有利于化合物抑菌活性的提高,可为进一步指导设计合成此类高活性化合物提供理论依据。     

沙葱内生菌的分离鉴定及抑菌活性

以荒漠植物沙葱为材料,分离筛选出对植物病原菌具有较强拮抗活性的内生菌,可为生防菌剂的开发提供材料。采用多种培养基通过稀释涂布法从沙葱根、茎、叶不同组织中分离出内生菌,进行形态学观察、分子生物学鉴定和抑菌活性研究。分离出的9株内生细菌均为芽孢杆菌属（Bacillus sp.）菌株,其中的ZT4、ZT5、ZT10和ZT14对7种植物病原真菌表现出较强的拮抗作用,以ZT14的拮抗作用最强,抑菌率均在65%以上。以ZT14为目标菌,研究其生物学性状与抑菌活性,发现该菌株在系统进化树上与解淀粉芽孢杆菌（Bacillus amyloliquefaciens）聚在同一分支,同源性为100%,由此将其鉴定为解淀粉芽孢杆菌;但ZT14次生代谢产物的抑菌活性较低,推测该菌株可能通过与病原菌竞争生长空间和营养而发挥抑菌作用。     

β-氨基醇类香紫苏醇衍生物的合成及抑菌活性

以香紫苏醇为先导化合物合成了24个β-氨基醇类衍生物,并采用菌丝生长速率法测试了目标化合物对5种植物病原菌的抑菌活性。初步构效关系分析结果表明：β-氨基醇类香紫苏醇衍生物的抑菌活性会受到苯环上连接基团性质及位置的影响,大部分间位取代衍生物的抑菌活性高于对应邻位和对位衍生物;与其他衍生物相比较,氟原子取代的衍生物2a～2c对5种供试病原菌均具有良好的抑菌活性,尤其对小麦赤霉病菌的抑菌活性最好,EC₅₀值分别为3.79、3.35和4.66μg/mL。     

土荆芥花序和叶挥发油的抑菌作用及组分分析

采用水蒸气蒸馏法分别提取采自河南信阳的土荆芥花序和叶的挥发油, 采用GC-MS进行组分分析, 并测定挥发油的抑菌作用。结果表明：土荆芥花序和叶的挥发油的含油率分别为4.02%和1.64%; GC-MS从挥发油中分别分离到10个和9个组分, 均鉴定出7个组分, 占挥发油总量的98.431%和99.103%; 挥发油的主要组分均为驱蛔素、2-蒈烯和α-松油烯, 但相对含量差异较大; 叶和花序的挥发油对小麦赤霉病菌具有强烈的熏蒸抑制作用, EC50 分别为1.46 μL/皿和1.80 μL/皿。     

Identification of antifungal compounds from the seed oil ofAzadirachta Indica

Evaluation of the activity of the cold expeller neem oil(Azadirachta indica A. Juss.) and the fractions derived through solvent partitioning, againstDrechslera oryzae, Fusarium oxysporum andAlternaria tenuis showed that the active antifungal fraction is a mixture of tetranortriterpenoids. Further, testing the triterpenoidal mixture derived from the 90% methanol (MeOH) extract of neem oil against 13 phytopathogenic fungi revealed that various species were inhibited to different degrees. Direct preparative High Performance Liquid Chromatography (HPLC) of the active fractions and subsequent bioassay of the semi-pure fractions indicated that the active fractions contained major compounds such as 6-deacetylnimbin, azadiradione, nimbin, salannin and epoxyazadiradione. Pure azadiradione, nimbin, salannin and epoxy-azadiradione did not have appreciable activity. However, when these terpenoids were mixed and bioassayed, they showed antifungal activity, indicating possible additive/synergistic effects.     

Chemical composition and phytotoxic activity of the volatile oil of invasive Xanthium italicum Moretti from Xinjiang, China

Aerial parts of Xanthium italicum in an air tight container greatly inhibited root elongation of radish,implying that this invasive plant could release biologically active volatile organic compounds(VOCs)into the environment to affect other plants' growth.This phenomenon was further studied by evaluating the phytotoxic effects of X.italicum essential oil against two dicot plants,amaranth(Amaranthus mangostanus L.)and lettuce(Lectuca sativa L.),and two monocot plants,wheat(Triticum aestivum Linn)and ryegrass(Lolium multiforum),and analyzing the chemical composition of the oil.Among the 4 test species,amaranth was the most sensitive plant,0.5μl/mL essential oil application resulted in a 50% reduction on root elongation,and 2.5 μl/mL essential oil almost completely inhibited its seedling growth.Wheat was the least sensitive species,whose root growth was reduced to 36% of control by 5 μl/mL essential oil.The essential oil exerted moderate inhibitory effect on both lettuce and ryegrass.Compared to a commercial herbicide-Harness,X.italicum oil exhibited stronger phytotoxicity on amaranth,lettuce and wheat,but weaker activity on ryegrass.The chemical composition of the essential oil isolated by hydrodistillation from the aerial parts of X.italicum Moretti was analyzed by GC/MS.Thirty two compounds were identified,representing 94.89% of total oil,which was found to be rich in monoterpene hydrocarbons(60.71%).The main constituents of the oil were limonene(51.61%),germacrene B(6.98%),δ-cadinol(5.94%),β-pinene(5.23%),α-caryophyllene(5.1%)and bornyl acetate(3.15%).Bioassay revealed the dominant constituent-limonene,was unlikely the responsible phytotoxic compound due to its low biological activity;rather,there might be other oil constituent(s)that either act alone,or work together,and possibly assisted by synergistic effect,to display the phytotoxic activity.Our results suggested that X.italicum might produce allelopathic VOCs to facilitate its invasion success.This is the first report on the phytotoxic activity and the chemical composition of the essential oil of X.italicum Moretti from China.     

深绿木霉HB20111产挥发性物质及其功能分析

为了解深绿木霉HB20111产挥发性物质的成分以及潜在的生物学功能,采用顶空气相色谱-质谱法测定了深绿木霉HB20111产挥发性物质的主要成分,并进行了成分分析;采用对扣法测定了深绿木霉HB20111产挥发性物质对5种植物病原菌的抑菌率;同时测定了深绿木霉HB20111产挥发性物质对小麦幼苗生长的影响。结果表明,深绿木霉HB20111产挥发性物质烯类的相对含量最高,为49.68%、醇类为21.78%,酮类为8.56%,其余类别相对含量较低;这些挥发性物质对5种植物病原菌均有一定的抑制效果,其中对立枯丝核菌抑菌率最高,为50.62%;挥发性物质还可以促进小麦幼苗生长,与对照相比,对小麦幼苗的株高有显著的促进作用(P<0.05)。这些结果为深绿木霉HB20111的开发应用提供了理论基础。     

Role of strawberry volatile organic compounds in the development of Botrytis cinerea infection

Botrytis cinerea, the main pathogen of strawberry, has the ability to remain quiescent in unripe tissue and develop disease symptoms in ripe fruit. As strawberry ripening is characterized by an increase of aroma compounds, the role of volatile emission in the development of infection was investigated. Thirty‐five strawberry volatile organic compounds (VOCs) were tested on B. cinerea in vitro and volatile emission was analysed in strawberry harvested at four ripening stages by headspace solid‐phase microextraction/gas chromatography–mass spectrometry and proton transfer reaction–time of flight–mass spectrometry. The coupling of such data sets made it possible to conclude that key strawberry aroma compounds stimulate B. cinerea conidial germination and some typical wound‐volatiles stimulate pathogen conidial germination or mycelial growth. This study is the first report of fungal stimulation by some VOCs naturally occurring in strawberry: the esters ethyl butanoate, cis‐3‐hexenyl acetate, trans‐2‐hexenyl acetate, methyl butanoate and hexyl butanoate, the furanones furaneol and mesifurane, and the alcohol trans‐2‐hexenol. The results of this work provide advances in understanding the functional role of fruit VOCs and suggest, for the first time, that fruit VOCs may influence the development of B. cinerea from the latent phase and that they could favour the invasive growth of B. cinerea after wounding. In particular, ethyl butanoate and furaneol could signal strawberry ripening, and the green leaf volatiles trans‐2‐hexenol, trans‐2‐hexenyl acetate and cis‐3‐hexenyl acetate could signal the presence of damaged tissues that are easier sites for penetration by B. cinerea.     

Biological activity of the essential oil from the leaves of Piper sarmentosum Roxb. (Piperaceae) and its chemical constituents on Brontispa longissima (Gestro) (Coleoptera: Hispidae)

The results showed that the essential oil from Piper sarmentosum has strong antifeedant and toxicity effects on Brontispa longissima. The best antifeedant and contact toxicity effects were observed in the 1st-2nd instar larvae. The essential oil also displayed a notable fumigation effect on the eggs and pupae of B. longissima. It took the control-treated insects 43.34 d to complete one generation, while the insects treated with 2000 mg/L essential oil needed 73.58 d. The essential oil was analyzed by gas chromatography/mass spectrometry and 41 components were identified. Myristicin (65.22%) and trans-caryophyllene (13.89%) were the major components. Myristicin exhibited strong antifeedant and contact toxicity effects on both the 3rd instar larvae and the imagoes of B. longissima, when it showed a significant fumigation effect on the eggs and pupae of B. longissima. Another P. sarmentosum essential oil and myristicin all showed a strong inhibiting effect on the growth and development of B. longissima along with the activity of AChE, CarE, GSTs and Na⁺, K⁺-ATPase in B. longissima larvae.