Adjuvants enhance the biological control potential of an isolate of Colletotrichum gloeosporioides for biological control of sicklepod (Senna obtusifolia)

In greenhouse experiments, unrefined corn oil, Silwet L-77, and an invert emulsion were tested as adjuvants with the mycoherbicidal fungus Colletotrichum gloeosporioides, a weakly virulent pathogen of sicklepod (Senna obtusifolia). A 1:1 (v/v) fungus/corn oil tank mixture containing 0.2% (v/v) Silwet L-77 surfactant reduced the dew period requirements for maximum weed infection and mortality from 16 to 8 h, and delayed the need for free moisture for greater than 48 h. This formulation also resulted in the ability of the pathogen to infect and kill weeds in larger (>5 leaf) growth stages. The invert emulsion resulted in similar effects upon these parameters. These results suggest that invert emulsions, unrefined corn oil and Silwet L-77 surfactant greatly improve the bioherbicidal potential of this pathogen for control of sicklepod, a serious weed pest in the southeastern US.     

Chemical composition and in vitro antibacterial activity of Seseli libanotis

Summary The antibacterial efficacy of the methanol extract of the aerial parts of Seseli libanotis by using disc diffusion assay against 107 strains from 52 bacterial species and the chemical composition of the essential oil using GC/MS analysis were studied for the first time. The minimum inhibitory concentrations (MIC) of single compounds were determined by the microbroth dilution method. Gas chromatography–mass spectrophotometry analyses allowed 13 compounds to be determined; the main constituents of the essential oil of aerial parts of Seseli libanotis were trans-caryophyllene (20.39%), spathulenol (11.89%), (−)-caryophyllene oxide (11.47%), euasarone (10.66%) and delta-cadinene (9.16%). The methanol extract of Seseli libanotis had a broad-spectrum antibacterial activity (>14 mm inhibition zone in diameter) in particular against Bacillus cereus, Bacillus dipsauri, Bacillus lentimorbus, Bacillus sphaericus, Bacillus subtilis, Corynebacterium ammoniagenes, Kocuria rosea, Neisseria subflava and Micrococcus lylae. These inhibitory effects are interesting in relation to the prevention of microbial contamination in foods.     

Circadian control of isoprene emissions from oil palm (Elaeis guineensis)

The emission of isoprene from the biosphere to the atmosphere has a profound effect on the Earth's atmospheric system. Until now, it has been assumed that the primary short-term controls on isoprene emission are photosynthetically active radiation and temperature. Here we show that isoprene emissions from a tropical tree (oil palm, Elaeis guineensis) are under strong circadian control, and that the circadian clock is potentially able to gate light-induced isoprene emissions. These rhythms are robustly temperature compensated with isoprene emissions still under circadian control at 38 degrees C. This is well beyond the acknowledged temperature range of all previously described circadian phenomena in plants. Furthermore, rhythmic expression of LHY/CCA1, a genetic component of the central clock in Arabidopsis thaliana, is still maintained at these elevated temperatures in oil palm. Maintenance of the CCA1/LHY-TOC1 molecular oscillator at these temperatures in oil palm allows for the possibility that this system is involved in the control of isoprene emission rhythms. This study contradicts the accepted theory that isoprene emissions are primarily light-induced.     

Marten Fur Harvests and Landscape Change in West-Central Alberta

ABSTRACT Trapping for furbearers remains an important outdoor activity in Alberta, Canada, despite low fur prices and extensive industrial development. We investigated the influence of landscape change on furbearer harvests using 30 years of marten (Martes Americana) harvest records, interviews with trappers, and Geographic Information System maps of industrial activity and vegetation types. We used an information-theoretic approach to explore variation in trapper success. Cover type and landscape metrics apparently influenced trapper success, because traplines where martens were consistently caught had less vehicle and all-terrain vehicle access, fewer oil and gas wells, and greater proportion of mature conifer forests than traplines where martens were infrequently caught. We identified an important cutoff value or statistical threshold that identified 45% closed-conifer cover, suggesting that a minimum amount of forest cover is crucial for trappers to catch martens. We conclude that the nature and extent of industrial disturbance is contributing to the decision by trappers to trap as well as influencing their success. We recommend that wildlife managers collect trapping effort information (i.e., species-specific no. of trap-nights) on fur reports in association with landscape changes to monitor furbearer harvests more effectively.     

Influence of Anthropogenic Structures on Northern Bobwhite Space Use in Western Oklahoma

ABSTRACT Anthropogenic structures associated with energy development and other activities are a growing concern in wildlife conservation because of habitat loss and fragmentation. We conducted a retrospective analysis of effects of barbed-wire fences, oil-extraction structures, aboveground power lines, resurfaced roads, and artificial water sites on space use by northern bobwhite (Colinus virginianus)in western Oklahoma, USA. Nest location data accrued during 1991–2002 and radiolocation data during 1997–2002. Data suggested fences had a weak repellent effect at distances <300 m, oil structures had neutral effects at distances <800 m, aboveground power lines had neutral effects at distances <250 m, resurfaced roads attracted at distances <350 m, and water sites had neutral effects at distances <250 m. Generally, anthropogenic structures seemed compatible with bobwhite populations on our study area, given density and dispersion of the structures that existed.     

Osmophore and elaiophores of Grobya amherstiae (Catasetinae,Orchidaceae) and their relation to pollination

Grobya amherstiae flowers release a honey‐like scent produced by an osmophore, comprising a papillate epidermis. The scent attracts bee pollinators (Paratetrapedia fervida), which collect floral oils produced by elaiophores on the lip apex and column base. The secretory tissue of the elaiophore on the lip apex consists of both palisade‐like epidermal cells and conspicuously elongated unicellular trichomes. From an anatomical point of view, this elaiophore differs in structure from those known in angiosperms to date. The elaiophore on the column base is exclusively composed of short unicellular trichomes. In addition, there is an elaiophore comprising a papillate epidermis on the internal surface of the lip. The elaiophores produce a heterogeneous secretion, composed of fatty acids and mucilage. The elaiophore on the internal surface of the lip produces oil in non‐collectible amounts, but it is enough to maintain the interest of the bees, guiding them to the elaiophore on the column base, a necessary step in pollination. The former elaiophore is here identified as an oil guide and it plays an essential role in ensuring pollination. The presence of three types of elaiophores on the flowers of this species of Orchidaceae is peculiar and noteworthy. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 408–415.     

Phytotoxic effects of Lantana camara, Eucalyptus camaldulensis and Eriocephalus africanus essential oils in weeds of Mediterranean summer crops

The essential oil composition of Lantana camara, Eucalyptus camaldulensis and Eriocephalus africanus was analyzed by means of GC and GC–MS and bioassayed in order to determine their activity against Amaranthus hybridus and Portulaca oleracea. E. camaldulensis essential oil, with spathulenol as the main compound, was the most effective, completely inhibiting germination and seedling growth on both weeds. The essential oil of E. africanus, rich in artemisia ketone, showed activity similar to that of E. camaldulensis on A. hybridus, but it was not so effective against P. oleracea, and L. camara essential oil, with high percentages in sesquiterpene hydrocarbons, also showed higher phytotoxic activity against A. hybridus, inhibiting its germination and seedling length; however, it showed no effect against P. oleracea germination, whereas was effective in significantly reducing its seedling growth at all concentrations assayed. The results suggest the possible use of these essential oils as natural herbicides.     

蝴蝶果根、果仁挥发油化学成分的研究

采用水蒸气蒸馏法从大戟科蝴蝶果的根和果仁中提取挥发油,用气相色谱-质谱联用技术对挥发油化学成分进行分析,并应用面积归一化法测定各成分的相对百分含量。从根中鉴定出23种化合物,占总油量的100%,其主要成分为十六烷酸(18.74%)、(Z,Z)9,12-十八碳二烯酸(12.81%)、1,2-苯二羧酸双(2-甲基丙基)酯(10.59%)、二丁基邻苯二甲酸酯(7.42%)及二十四烷(6.72%)。从果仁中鉴定出17种化合物,占总油量的100%,主要成分为(E-)-9-十八碳烯酸(23.15%)、正十六烷酸(21.20%)、(Z,Z)-9,12-十八碳二烯酸(19.26%)及3-甲基十七烷(6.80%)。     

气相色谱质谱联用技术对栝楼籽油亚麻酸和亚油酸含量的分析

通过皂化法和尿素包合法对热榨、冷榨栝楼（Trichosanthes kirilowii）籽油进行提取,采用气相色谱-质谱联用（GC-MS）技术检测分析栝楼籽油中亚麻酸、亚油酸成分、含量。结果表明,热榨栝楼籽油中亚麻酸相对含量为4.16%～11.58%,亚油酸相对含量为68.62%～95.84%。冷榨栝楼籽油中不含亚麻酸成分。此方法适用于栝楼籽油的成分分析。     

含油废水处理工艺中细菌多样性

从辽河油田曙光污水处理厂含油废水样品中直接抽提细菌总DNA,并对总DNA中16S rRNA V3可变区序列作PCR扩增、变性梯度凝胶电泳(DGGE),与常规水质分析相结合对系统中不同处理阶段细菌种群多样性和水质之间的关系进行分析.结果表明,处理系统的不同处理阶段细菌的多样性有明显差异,既存在共同的细菌种属,也存在着各自独特的细菌种属,且细菌种群的多样性与水质CODcr和总石油烃(TPH)的浓度呈负相关,细菌种群的多样性越高,CODcr和TPH的浓度越低,反之则越高.在处理过程中,随着样品中细菌多样性的增加,种群结构之间的相似性指数(C_8)逐渐升高,最后形成了稳定的种群结构.