薇甘菊挥发油的化感潜力

外来植物薇甘菊 (MikaniamicranthaKunth .)已成为华南地区重要的杂草 ,其挥发油对植物、真菌和细菌均具有生物活性 ,对植物和水稻稻瘟病菌的抑制活性尤其显著 .随着薇甘菊挥发油浓度 (2 0 0、4 0 0、80 0、16 0 0mg·L-1)的增加 ,6种受试植物幼苗的生长随之明显减弱 .薇甘菊挥发油 (2 5 0 0 g·hm-2 )土壤处理 ,受试的 6种植物鲜重明显减少 ,出苗时间推迟 1～ 2d .薇甘菊挥发油在中等浓度 (40 0mg·L-1)时 ,对水稻稻瘟病菌的抑制作用最强 ,抑菌率为 5 3.38%;对香蕉枯萎病菌的抑制作用次之 ,抑菌率为2 8.6 6 %;对长春花疫病菌的抑制作用最弱 ,抑菌率为 18.6 9%.     

胜红蓟化感物质之间相互作用的研究

 通过柱层析从胜红蓟挥发油中分离出早熟素Ⅰ、早熟素Ⅱ、子丁香烯、3,3-二甲基-5-特丁基茚酮、红没药烯、乙酸葑醇酯等6种主要化感物质(占挥发油总量的97％),并研究了这些化感物质在挥发、淋溶(饱和水溶液)和土壤降解途径下对萝卜,番茄和绿豆幼苗的化感作用。结果表明：早熟素Ⅰ、早熟素Ⅱ、3,3-二甲基-5-特丁基茚酮及子丁香烯(挥发途径)虽有较强的化感活性,但均弱于挥发油的化感活性,而子丁香烯(淋溶途径),红没药烯和乙酸葑醇酯则基本无化感活性。但是,早熟素n和无活性的三个化感物质结合,则表现出强烈的化感活性,说明胜红蓟各化感物质之间存在着明显的协同作用。     

胜红蓟化感作用研究Ⅲ.挥发油对不同营养水平下植物的化感作用

研究了胜红蓟挥发油对不同营养水平下植物的化感作用．结果表明,随着营养水平的降低,胜红蓟挥发油对受试植物的化感作用明显增强．在胜红蓟挥发油的作用下,受试植物叶绿素和可溶性蛋白含量明显降低,过氧化物酶（ＰＯＤ） 活性降低,而质膜相对透性增加,丙二醛（ ＭＤＡ） 含量升高．利用ＧＣ／ ＭＳ对胜红蓟挥发油的组成和含量进行了分析,共鉴定１６ 种物质,其中早熟素Ⅱ、早熟素Ⅰ和子丁香烯为主要成分,相对含量分别为３６ ．８５ ％ 、２６ ．４１ ％ 和１９ ．８４ ％ ．     

胜红蓟化感作用研究Ⅰ.水溶物的化感作用及其化感物质分离鉴定

研究了胜红蓟水溶物对植物的化感作用 .结果表明 ,胜红蓟水溶物溶液浓度在0 .2 5gFW·ml- 1 时对所有供试植物的萌发和幼苗生长均有显著的抑制作用 ,浓度降至0 .1 0 gFW·ml- 1 时其抑制作用基本消失 ;胜红蓟不同器官、不同生育期水溶物的化感作用是有差异的 ,特别是不同生境条件下生长的胜红蓟水溶物化感作用有显著差异 ,表明在恶劣生境下胜红蓟的化感作用更为强烈 .对胜红蓟水溶物中的化感活性物质进行分离和分子结构鉴定 ,得到早熟素Ⅰ、早熟素Ⅱ和 5,2 2 二烯 3β 豆甾醇 3个化感化合物 .     

加拿大蓬挥发油化感作用及其释放途径的研究

采用半密闭容器法对加拿大蓬挥发油的化感作用进行了生物测定,并对采用挥发、淋溶2种不同途径释放加拿大蓬挥发油中次生代谢产物对受体植物--大白菜、小白菜、苦苣造成的影响进行了比较分析.结果发现:(1)加拿大蓬挥发油对3种植物种子萌发和幼苗生长均具有不同程度的抑制作用,GC-MS分析显示其挥发油中具有化感潜力的单萜类物质含量超过60%.(2)加拿大蓬挥发油以挥发的方式作用于受体植物时,植物苗长的生长存在"低促高抑"现象,其对根长的抑制作用明显强于苗长;而挥发油淋溶物则同时抑制幼根、幼茎的发育.(3)3种受体植物中小白菜对加拿大蓬挥发油的化感作用最敏感,而苦苣则受挥发油淋溶物的影响最大.说明除挥发外,加拿大蓬挥发油的淋溶物也可对受体植物产生化感作用,并且以不同途径释放加拿大蓬挥发油时,其化感作用存在差异.     

红树植物秋茄叶片水提物的抑藻效应

通过藻细胞密度的测定,探讨了不同浓度(0.5、1.0和2.0g·L-1)红树植物秋茄(Kandelia candel)新鲜叶片水提物对球形棕囊藻(Phaeocystis globosa)和赤潮异弯藻(Heterosigma akashiwo)的化感抑制效应,研究了高温处理对秋茄提取物化感作用的影响.结果表明:秋茄叶片提取物对两种赤潮藻均具有显著的化感抑制作用,不同浓度提取物化感作用强度不同;5 d内,浓度为2.0g·L-1秋茄叶片提取物对球形棕囊藻和赤潮异弯藻的最大抑制率分别为91.6％和77.0％;球形棕囊藻和赤潮异弯藻对红树植物秋茄提取物的敏感性不同,提取物对球形棕囊藻的抑制效果要优于赤潮异弯藻;经高温处理后,秋茄提取物抑藻效果显著降低(P＜0.05);秋茄叶片水提物影响藻细胞膜结构,使藻细胞体积增大、细胞破裂.     

胜红蓟化感作用研究 Ⅱ.主要化感物质的释放途径和活性

研究了南方重要杂草胜红蓟(Ageratumconyzoides)挥发物质的化感作用。结果表明,胜红蓟鲜叶的挥发物质和挥发油对所有受试植物的幼苗生长有显着的抑制作用。用色谱法鉴定并分离了胜红蓟挥发油的主要成分早熟素Ⅰ和早熟素Ⅱ,两者分别占总量的30.93%和51.61%.胜红蓟水溶物中的早熟素Ⅰ和Ⅱ是从挥发物中而来,挥发是胜红蓟释放化感物质的主要途径。分离纯化的早熟素Ⅰ和Ⅱ的饱和水溶液对萝卜、番茄和黑麦草的幼苗生长均有显着的抑制作用,特别是早熟素Ⅱ具有强烈的化感作用,在25μg·ml^-1低浓度下,仍能抑制植物幼苗的生长,但早熟素Ⅰ和Ⅱ的混合溶液对植物的抑制作用并无显着增强,两者之间不存在协同作用。     

入侵植物意大利苍耳不同部位挥发油的化感作用及其化学成分的比较分析

采用水蒸气蒸馏法分别提取意大利苍耳(Xanthium italicum Moretti)叶、茎、果3个部位的挥发油,并通过GC-MS分析对其化学成分进行分析鉴定。在叶、茎、果挥发油中分别鉴定出25、23和27种化合物,分别占总成分的90.625%、93.041%和89.866%。其中,叶挥发油的主要成分是柠檬烯(25.541%)和龙脑(12.133%),茎挥发油的主要成分是柠檬烯(62.85%),而果挥发油的主要成分为γ-榄香烯(23.38%)、柠檬烯(14.18%)和吉玛烯B(16.279%)。以意大利苍耳入侵生境中常见杂草反枝苋(Amaranthus retroflexus L.,双子叶植物)和早熟禾(Poa pratensis L.,单子叶植物)作为受试植物,在密闭容器中(容积为1.4 L)放入不同质量的叶、茎、果部位(20 g、40 g和80 g),检测其在模拟自然状态下产生的挥发物的化感作用;并采用培养皿法对不同浓度叶、茎、果挥发油(0.2μL/m L、0.5μL/m L、1μL/m L、3μL/m L和5μL/m L)的化感作用进行生测。结果显示:意大利苍耳各部位在自然挥发条件下以及其挥发油均表现出较强的化感作用,其叶挥发油在5μL/m L时可完全抑制两种受试植物种子的萌发,具有进一步开发为植物源除草剂的潜力。     

薇甘菊挥发油的化感潜力

外来植物薇甘菊(Mikania micrantha Kunth.)已成为华南地区重要的杂草,其挥发油对植物、真菌和细菌均具有生物活性,对植物和水稻稻瘟病菌的抑制活性尤其显著.随着薇甘菊挥发油浓度(200、400、800、1600mg·L^-1)的增加,6种受试植物幼苗的生长随之明显减弱.薇甘菊挥发油(2500g·hm^-2)土壤处理,受试的6种植物鲜重明显减少,出苗时间推迟1～2d.薇甘菊挥发油在中等浓度(400mg·L^-1)时,对水稻稻瘟病菌的抑制作用最强,抑菌率为53.38%;对香蕉枯萎病菌的抑制作用次之,抑菌率为28.66%;对长春花疫病菌的抑制作用最弱,抑菌率为18.69%.     

胜红蓟化感作用研究Ⅵ.气象条件对胜红蓟化感作用的影响

在田间条件下 ,胜红蓟化感作用与光、温、水等气象要素显著相关 ,有利的光、温、水生长条件使得其化感作用减弱 ,反之增强 .春夏季温度和降水有利胜红蓟的生长 ,其化感作用减弱 ,而秋冬季温度和降水不利胜红蓟生长 ,其化感作用增强 .实验表明 ,30 0 μg·ml-1高浓度胜红蓟挥发油使受试植物不能生长 ,而6 0 μg·ml-1低浓度影响较小 ,在高温、低温和遮光等不利植物生长的条件下 ,低浓度的胜红蓟化感物质对受试植物的抑制效应显著增强 ,显示在不利的生长条件下 ,受试植物对胜红蓟化感物质的抵御能力减弱 .研究表明 ,在不利于胜红蓟及受试植物生长的气象条件下 ,胜红蓟化感作用增强 ,受试植物抵御化感物质的能力降低 ,使得胜红蓟群落中其它植物难以正常生长 ,相应地提高了胜红蓟在自然群落中的竞争优势 .化感作用和光、温、水、气象条件的共同作用是胜红蓟在自然群落中成为优势种群的重要原因之一 .     

马缨丹叶片精油化学成分及其对三种害虫的生物活性

【目的】为探讨马缨丹Lantana camara L.叶片精油化学成分以及其对3种害虫的生物活性,以应用于生物防治。【方法】马缨丹叶片经水蒸气蒸馏法提取精油,产率为0.21%。经过气-质联用仪(GCMS)分析,从马缨丹叶片精油中检测出主要的26种化合物,其中α-姜黄烯(α-curcumene,32.76%),β-石竹烯(β-caryophyllene,16.36%),石竹烯氧化物(Caryophyllene oxide,12.22%),桉油烯醇(Spathulenol,10.48%)含量较高,并对3种不同害虫进行生物活性测定。【结果】生物测定结果表明,马缨丹精油对米象Sitophilus oryzae成虫和Ⅳ龄埃及伊蚊Aedes aegypti幼虫的触杀效果显著,LC50分别为0.92 mg/cm2和32.33μg/m L。随着浓度的升高,对白蚁驱避作用增强,白蚁死亡率增加;高浓度精油对白蚁有触杀作用,但较低浓度对白蚁无显著影响。【结论】本研究证明马缨丹叶片精油对3种害虫有良好防治的效果。     

马缨丹抑菌试验研究

目的：研究马缨丹的体外抑菌效果。方法：制备马缨丹水煎煮液和乙醇提取液,测定其对枯草芽孢杆菌、大肠杆菌和金黄色葡萄球菌的抑菌圈直径、最小抑菌浓度及灭菌前后提取液抑菌效果的变化。结果：当两种提取液生药含量大于0.4 g/mL时,它们对三种细菌的抑菌效果依次为：枯草芽孢杆菌〉金黄色葡萄球菌〉大肠杆菌。马缨丹乙醇提取液对三种细菌的最小抑菌浓度分别为1/64g/mL1、/16g/mL和1/32g/mL,都比水煎煮液的结果1/32g/mL、1/8g/mL和1/16g/mL低。两种提取液经121℃高压蒸汽灭菌处理后对枯草芽孢杆菌和金黄色葡萄球菌的抑制作用有所增强。结论：两种提取液对三种细菌均有不同程度的抑制作用,因此,马缨丹可考虑用于食品、化妆品及饲料防腐等领域,以提高产品质量。     

Chemical composition and antimicrobial activity of the essential oils of the Amazon Guatteriopsis species

The essential oils of Guatteriopsis blepharophylla, Guatteriopsis friesiana and Guatteriopsis hispida were obtained by hydrodistillation and analysed by GC and GC/MS. The main compound found in the leaf oil of G. blepharophylla was caryophyllene oxide (1) (69.25%). The leaf oil of G. friesiana contained predominantly beta-eudesmol (2) (51.60%), gamma-eudesmol (3) (23.70%), and alpha-eudesmol (4) (14.56%). The major constituents identified in the leaf of G. hispida were beta-pinene (38.18%), alpha-pinene (30.77%) and (E)-caryophyllene (20.59%). The antimicrobial activity of the essential oils was evaluated against 11 species of microorganisms. The oil of G. friesiana exhibited significant antimicrobial activity for all microorganisms tested, whereas that of G. hispida and G. blepharophyla had potent activity against Rhodococcus equi with MIC of 50 microg mL(-1). The major constituents of each oil were also tested separately, and showed lower activity compared to the oils. Moreover, mixtures of the main constituents, in the same proportions found in G. friesiana and G. hispida oils, did not show the same activity as the original oils.     

Essential Oils of Polyalthia suberosa Leaf and Twig and Their Cytotoxic and Antimicrobial Activities

Essential oils from the leaf and twig of Polyalthia suberosa (Roxb.) Thwaites were analyzed using GC/MS/FID. A total of sixty-three constituents were namely identified accounting for 96.03 and 94.12 % in the hydrodistilled oils of the leaf and twig, respectively. Monoterpenes, monoterpenoids, sesquiterpenes, and sesquiterpenoids were characteristic derivatives of P. suberosa essential oils. Sesquiterpenes bicyclogermacrene (26.26 %) and (E)-caryophyllene (7.79 %), and monoterpene β-pinene (12.71 %) were the major constituents of the leaf oil. Sesquiterpenes (E)-caryophyllene (17.17 %) and α-humulene (9.55 %), sesquiterpenoid caryophyllene oxide (9.41 %), and monoterpenes camphene (8.16 %) and tricyclene (6.35 %) were to be main components in the twig oil. The leaf oil indicated cytotoxic activity against three cancer cell lines HepG2, MCF7 and A549 with the IC₅₀ values of 60.96–69.93 μg/mL, while the twig oil inhibited MCF7 with the IC₅₀ value of 66.70 μg/mL. Additionally, the twig oil successfully suppressed the growth of the negative Gram bacterium Pseudomonas aeruginosa, fungus Aspergillus niger, and yeast Candida albicans with the same MIC value of 50 μg/mL, whereas the leaf oil had the same result on the negative Gram bacterium Escherichia coli.     

Inhibitory effects of monoterpenes on seed germination and seedling growth

Monoterpenes, the chemical constituents of essential oils found in plants, are known biologically active compounds. The present study was conducted to investigate the inhibitory effects of 30 monoterpenes including monoterpene hydrocarbons and oxygenated monoterpenes on seed germination and seedling growth of Amaranthus retroflexus, Chenopodium album and Rumex crispus under laboratory conditions. The monoterpenes were applied at contents of 10 and 20 microl for liquid compounds and 10 and 20 microg for solid compounds. The results show that most of the monoterpenes significantly inhibited seed germination and seedling growth of the tested plants. Oxygenated monoterpenes including beta-citronellol, nerol and terpinen-4-ol completely inhibited seed germination and seedling growth of all tested plants. Their inhibitory effects were also stronger than that of the herbicide 2,4-D. In general, monoterpenes were less effective against seed germination and seedling growth of C. album as compared with R. crispus and A. retroflexus. Phytotoxic effects of monoterpene hydrocarbons were found to be lower than those of oxygenated monoterpenes. The alcohol derivatives of oxygenated monoterpenes were also found to be more phytotoxic as compared with their acetate derivatives. Based on the present results, it can be concluded that the oxygenated monoterpenes can be used as potential bio-herbicides.     

葎草挥发性物质化感作用及其化感物质的分析研究

以小麦、生菜、萝卜、黄瓜4种作物为受体,检测了葎草[Humulus scandens（Lour.）Merr]挥发性物质的化感潜势,并采用气相色谱-质谱联用仪对其化感物质进行了初步鉴定.结果表明：新鲜葎草茎叶在密闭系统中释放的挥发性物质对4种受试植物幼苗的生长有极显著的抑制作用（P＜0.01）;用石油醚提取风干葎草茎叶,得到的挥发性物质在密闭系统中对4种受试植物幼苗的生长也具有极显著的抑制作用（P＜0.01）;提取物在2、5、10、20、40、100、200mg/mL等7个不同浓度下,对受试植物生长和种子萌发表现为＂低促高抑＂的化感潜势,且随提取液浓度增大抑制作用增强;GC-MS鉴定出26种有机化合物,主要包括脂肪酸、甾体、萜类及其含氧化合物,均属前人研究较多的生物活性物质.这些结论为利用野生葎草资源挥发物开发新型除草剂等提供依据.     

Salvia verbenaca L. essential oil: Variation of yield and composition according to collection site and phenophase

The effect of the collection sites and phenophase on yield and chemical composition of Salvia verbenaca essential oils was evaluated. The essential oil constituents were assessed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The highest essential oil yields were observed for samples of the higher semi-arid bioclimate and at the flowering period. Eighty-five volatile constituents were identified and their percentages varied significantly (p < 0.05) depending on the collection site and the phenological stage. According to the plants origin, essential oils were dominated by monoterpene hydrocarbons, oxygenated monoterpenes and sesquiterpene hydrocarbons. The monoterpene hydrocarbons (31.9%) predominate at the flowering stage whereas oxygenated sesquiterpenes (27.5%) at the early fruiting stage. The sesquiterpene hydrocarbons (28.2%) was the most represented chemical class at late fruiting. On the basis of GC-MS data, the major identified volatile constituents were viridiflorol (3.4–17.7%), α-pinene (0.7–15.9%), β-caryophyllene (1.0–15.3%) and p-cymene (1.3–14.2%). S. verbenaca contains a diversity of bioactive constituents which shows large variations as affected by the collection sites and phenophase.     

四种与福寿螺(Ampullaria gigas)同源地入侵植物的杀螺效果

实验室内观察了福寿螺在其主要危害对象水稻,及与其同源地的入侵植物五爪金龙、马缨丹、胜红蓟和蟛蜞菊５种植物新鲜叶片间聚集数量差异,结果显示:15min后福寿螺在距离其约75cm 的5种植物叶片聚集数产生了显著的差异,但75min内福寿螺在5种植物叶片间聚集的数量不稳定,75min后的聚集数趋于稳定,5种植物叶片上聚集福寿螺数由多到少顺序为蟛蜞菊、马缨丹、水稻、胜红蓟和五爪金龙。福寿螺取食水稻幼苗的量较大,显著高于取食另4种植物新鲜叶片的量,福寿螺取食4种与其同源地植物叶片量由小到大的顺序为：五爪金龙、蟛蜞菊、胜红蓟和马缨丹。不同浓度4植物乙醇提取物水溶液对福寿螺毒杀作用差异显著,乙醇提取物饱和水溶液致福寿螺100%死亡的时间由短到长的顺序为：五爪金龙48h, 蟛蜞菊72h, 胜红蓟和马缨丹均为96h,按常规施用量化学农药密达100%毒杀福寿螺的时间为118h。综合结果表明五爪金龙具有开发出既能有效防治福寿螺又不影响水稻生长和稻田环境材料的潜力。     

Repellent plants provide affordable natural screening to prevent mosquito house entry in tropical rural settings--results from a pilot efficacy study

Sustained malaria control is underway using a combination of vector control, prompt diagnosis and treatment of malaria cases. Progress is excellent, but for long-term control, low-cost, sustainable tools that supplement existing control programs are needed. Conventional vector control tools such as indoor residual spraying and house screening are highly effective, but difficult to deliver in rural areas. Therefore, an additional means of reducing mosquito house entry was evaluated: the screening of mosquito house entry points by planting the tall and densely foliated repellent plant Lantana camara L. around houses. A pilot efficacy study was performed in Kagera Region, Tanzania in an area of high seasonal malaria transmission, where consenting families within the study village planted L. camara (Lantana) around their homes and were responsible for maintaining the plants. Questionnaire data on house design, socioeconomic status, malaria prevention knowledge, attitude and practices was collected from 231 houses with Lantana planted around them 90 houses without repellent plants. Mosquitoes were collected using CDC Light Traps between September 2008 and July 2009. Data were analysed with generalised negative binomial regression, controlling for the effect of sampling period. Indoor catches of mosquitoes in houses with Lantana were compared using the Incidence Rate Ratio (IRR) relative to houses without plants in an adjusted analysis. There were 56% fewer Anopheles gambiae s.s. (IRR 0.44, 95% CI 0.28-0.68, p<0.0001); 83% fewer Anopheles funestus s.s. (IRR 0.17, 95% CI 0.09-0.32, p<0.0001), and 50% fewer mosquitoes of any kind (IRR 0.50, 95% CI 0.38-0.67, p<0.0001) in houses with Lantana relative to controls. House screening using Lantana reduced indoor densities of malaria vectors and nuisance mosquitoes with broad community acceptance. Providing sufficient plants for one home costs US $1.50 including maintenance and labour costs, (30 cents per person). L. camara mode of action and suitability for mosquito control is discussed.