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1.
Orobanche hederae Duby and its host Hedera helix L. were collected in the North Italian Trentino-Südtirol region and analyzed for their content of polyacetylenes. Both, the host plant (Hedera) and the parasite (Orobanche) contained the polyacetylene falcarinol and two of its dehydroderivatives. The contents of polyacetylenes in Hedera decrease from roots via stems to leaves and contents in Orobanche are only about one-tenth of the contents in the Hedera roots it parasites on. Moreover, relative contents of the more polar polyacetylenes are higher in Orobanche than in Hedera, implying a bias toward the sequestration of more polar compounds.  相似文献   

2.
A comparative palynological study of 25 taxa of the genus Orobanche L. belonging to section Trionychon Wallr. and section Orobanche L. was carried out. A clear difference between the pollen grains of section Trionychon and section Orobanche was observed. The grains of section Trionychon are typically tricolpate, radially symmetrical, more or less oblate spheroidal, with a microreticulate, or scabrate-perforate sculpture. Section Orobanche on the other hand, had spheroidal, more or less inaperturate pollen grains, although some were tricolpate, but without any clear symmetry. The basic surface sculpture of the pollen in section Orobanche was scabrate to rugulate-perforate. Palynoiogicaliy, six groups can be recognized amongst the species of the genus Orobanche , lor which a key is provided.  相似文献   

3.
Treehoppers (Hemiptera: Membracidae) are sap-feeding insects distributed mainly in tropical regions. Alchisme grossa is a treehopper that has been reported in the Bolivian Yungas forests using mostly Brugmansia suaveolens (Solanaceae) as host-plant, where adult females oviposit and take care of their nymphs until they molt to adults. Brugmansia is a subtropical genus producing a variety of tropane alkaloids (TAs). We herein report the sequestration by adult males and females of A. grossa of TAs from B. suaveolens, examining separately the distinct body sections of insects. Purified extracts of A. grossa and B. suaveolens were analyzed by gas chromatography/mass spectrometry. TAs in A. grossa were the same as those in its host-plant; furthermore, they were equally distributed between sexes and they were differentially allocated within the body of adult individuals. An ecological role for sequestered TAs is discussed.  相似文献   

4.
Bacteria of the faba bean (Vicia faba L.)/Orobanche spp. root environment were evaluated for their potential use as biocontrol agents for the parasitic weed. Bacteria were isolated mainly from the rhizosphere of faba bean as well as from diseased Orobanche underground structures and an Orobanche-suppressive soil from three districts of northern Tunisia. Out of 351 bacterial isolates, 337 were tested for pathogenicity in an inverted pyramidal-shape screening programme including a Lactuca sativa L. seedlings bioassay, root-chamber and pot experiments. In pre-selection screening on L. sativa seedlings, 37 isolates (11%) showed a strong growth inhibitory effect, of which 70 and 84% also had a significant suppressive activity on the pre-emergence structures of O. foetida and O. crenata, respectively, in root-chamber experiments. Among five bacterial isolates selected for pot trials, strain Bf7-9 of Pseudomonas fluorescens showed high biocontrol activity against both species of Orobanche and positively influenced faba bean growth. The bacterium reduced shoot emergence of O. crenata and O. foetida by 64 and 76% and their dry weight by 39 and 63%, respectively, compared with non-inoculated controls. Pseudomonas marginalis strain Nc1-2 exhibited also a tendency to reduce incidence of O. crenata and to improve faba bean performance. Results of the present study suggest that application of naturally occurring rhizosphere bacteria offers an additional approach for biocontrol of Orobanche spp. that can supplement current methods of control in an integrated weed management strategy.  相似文献   

5.
Aims Melampyrum pratense and M. subalpinum are two myrmecochorous species, which possess similar habitat requirements and frequently occur together. Despite this, their population sizes differ markedly. Melampyrum pratense populations are usually very large, whereas M. subalpinum has rather small and isolated populations. We suggest that such an imbalance might be partially influenced by the difference in ant-mediated seed-removal rates. Genus Melampyrum is considered to be exclusively myrmecochorous, though to achieve the recent distribution of some Melampyrum species during the Holocene myrmecochory would be highly insufficient. We suggest that endozoochory takes place in the long-distance migration, whereas myrmecochory is important for the removal of seeds on a local scale.Methods For seed-preference analysis, M. pratense and M. subalpinum mixed seed samples were placed around Formica polyctena anthills. After a period of time, the remaining seeds of both species were counted for each sample. The results were analysed by analysis of variance and generalized linear mixed-effect model. To test myrmecochorous removal distances, M. pratense seeds were covered with fluorescent dactyloscopic powder and placed in the vicinity of a large ant trail. The area around the starting plot was searched in the dark using UV LED torchlight 7h after the beginning. The distance from the starting plot was measured for each seed found. Birds, rodents, leporine and a ruminant were fed with M. pratense seeds and fresh plants to test the possibility of endozoochorous dispersal of the species. Animal droppings were searched for intact seeds.Important findings Our field studies show that from mixed seed samples, containing both species, ants significantly preferred the seeds of M. pratense. This may be one of factors that has positive influence on M. pratense success in seed dispersal on mixed stands and consequently in the colonization of favourable sites. Experiments focusing on ant-mediated dispersal distance revealed that F. polyctena ants are able to move seeds over a distance of 36 m in only 7h. This distance is among the furthest known myrmecochorous removals of forest plant seeds. A new Melampyrum seed disperser Oligolophus tridens (Opiliones) was observed repeatedly. Our pilot study documented that Melampyrum seeds are able to pass through the digestive tract of a cow intact. This suggests that large ruminants such as deer, bison or forest-grazing livestock may function as important long-distance dispersers of Melampyrum species.  相似文献   

6.
Broomrape (Orobanche ramosa L.) is a root holoparasite responsible for important yield losses in numerous crops, particularly in the Mediterranean area. In this paper, the effects of temperature, oxygen concentration and water potential of the medium on broomrape seed germination were investigated. Seeds became able to germinate in the presence of a strigol analogue (GR 24) only after a preincubation period for at least 3 days at 20 °C. Their responsiveness to GR 24 increased with increasing duration of their preconditioning at 20 °C, and was optimal after 2–3 weeks. The preconditioning treatment was effective at temperatures ranging from 10 to 30 °C. At the optimal temperature (20 °C), it required at least 1% oxygen in the atmosphere and remained effective at a water potential of the medium of –2 MPa. A too prolonged preincubation of seeds at sub- or supraoptimal temperatures (5 and 30 °C) resulted in induction of a secondary dormancy. Seeds preconditioned for 14 days at 20 °C germinated in the presence of 1 mg L–1 GR 24 at temperatures ranging from 10 to 25 °C, and the thermal optimum was the same (20 °C) than that of preconditioning. At 20 °C, seeds were able to germinate in the presence of GR 24 under atmospheres containing at least 3% oxygen and at a water potential of the medium as low as –3 MPa. The differences observed in the effects of environmental factors on preconditioning efficiency and germination of preconditioned seeds suggest that both processes involve different mechanisms. The results obtained might also help to better understand the regulation of O. ramosa spread in temperate areas.  相似文献   

7.
Most members of the nonphotosynthetic parasitic genera Orobanche and Phelipanche (Orobanchaceae) have narrow host ranges, and, as they grow on perennial hosts, are (at least potentially) perennial themselves. A few species, however, have wide host ranges and grow on annual hosts, and are thus (at least facultatively) annuals themselves. Among the latter are the weedy species, which include economically important pest taxa such as Orobanche crenata or Phelipanche aegyptiaca. Using a phylogenetically based maximum likelihood approach, which takes phylogenetic and branch length uncertainty into account, we can show that the life trait host range and life history evolve in a correlated fashion. This supports the hypothesis that parasite specialization is associated with predictable resources (i.e. long-lived hosts) and generalism with unpredictable ones (i.e. short-lived hosts), a pattern often found in animal parasites. The mechanisms and temporal sequence of the life trait changes and their interrelations remain speculative.  相似文献   

8.
白背三七叶中吡咯里西啶生物碱的LC—MS^n检测   总被引:3,自引:0,他引:3  
广泛分布于植物中的吡咯里西啶生物碱(pyrrolizidine alkaloids,PAs)由具有双稠吡咯啶环的氨基醇与不同有机酸缩合而成,醇部分为裂碱(necine),酸部分为裂酸(necicacid)。以裂碱的结构可划分为2种类型,即倒千里光裂碱型(retronecine—type,RET型)和奥托千里光裂碱型(otonecinetype,OTO型)。  相似文献   

9.
假烟叶树叶挥发油化学成分分析   总被引:1,自引:0,他引:1  
采用水蒸汽蒸馏法、两相溶剂萃取法提取,运用毛细管气相色谱-质谱联用法结合计算机检索对茄科植物假烟叶树(Solanum verbascifoliumL.)叶挥发油的化学成分进行分析和鉴定。其新鲜叶片提取10 h的挥发油得率为0.0611%。经毛细管色谱分离出18个峰,共鉴定出17种化合物,占挥发油总量的99.73%;用气相色谱面积归一化法计算各组分的相对含量,其主要化学成分为:大牻牛儿烯D(37.07%),咕巴烯(26.29%),1β-(1-甲基乙基)-4,7-二甲基-1α,2,4a()β,5,8,8a()α-六氢萘(13.63%),石竹烯(8.03%),1-β乙烯基-1-α甲基-2,β4-β双(1-甲基乙烯基)-环己烷(5.81%),-γ榄香烯(2.16%),α-筚澄茄油烯(2.06%),异喇叭烯(0.98%)。以上8种化合物占总挥发油含量的90.22%。  相似文献   

10.
Whether administration of total alkaloids from Commelina communis L. (TAC) reduces lung damage in influenza virus-infected mice was investigated. Compared with untreated mice, significantly less severe damage was found in the lungs of mice administered TAC at 8 mg/kg per day for 6 days. TAC significantly decreased viral loads in the lungs. The concentrations of IFN-γ in the serum of TAC-treated mice were significantly lower than those of virus control mice at 4 and 6 days post-infection. The results indicate that TAC imparted partial protection to the mice by reducing pulmonary viral loads and limiting lesions in the lungs.  相似文献   

11.
以种子萌发率、幼苗根长、幼苗株高和单株鲜质量以及菌落直径为指标,对碎米莎草(Cyperus iria L. )穗部总生物碱的化感活性及抑菌效果进行了初步研究.结果表明,不同质量浓度的总生物碱溶液对6种供试植物的种子萌发和幼苗生长均有不同程度的影响;质量浓度为500~4 000 mg·L~(-1)的总生物碱溶液对水稻(Oryza sativa L. )种子萌发率和幼苗的株高和单株鲜质量无显著影响(P>0.05),但4 000 mg·L~(-1)总生物碱溶液对水稻幼苗的根长有显著的抑制作用(P<0.05);总生物碱溶液对烟草(Nicotiana tabacum L. )、鳢肠[Eclipta prostrata (L. ) L. ]、千金子[Leptochloa chinensis (L. ) Nees]、三叶鬼针草(Bidens pilosa L. )及丁香蓼(Ludwigia prostrata Roxb. )的种子萌发和幼苗生长的抑制作用随质量浓度的提高而增强,且当质量浓度达到4 000 mg·L~(-1)时, 种子萌发率和幼苗的根长、株高和单株鲜质量均最低, 与对照差异显著(P<0.05). 碎米莎草穗部总生物碱溶液对6种供试植物病原真菌的抑菌效果有一定的差异, 但总体上随质量浓度(25~400 mg·L~(-1))的提高抑菌效果逐渐增强;当质量浓度达到400 mg·L~(-1)时,总生物碱溶液对苹果轮纹病病菌(Physalospora piricola Nose)、油菜菌核病病菌[Sclerotinia sclerotiorum (Lib. ) de Bary]、水稻稻瘟病病菌[Magnaporthe grisea (Hebert) Barr. ]、小麦赤霉病病菌(Fusarium graminearum Schw. )和番茄早疫病病菌(Alternaria solani Jones et Grout. )的抑菌率最高,分别达到74.05%、64.73%、43.54%、35.09%和32.56%,与对照差异显著(P<0.05);但25~400 mg·L~(-1)总生物碱溶液对杨树溃疡病病菌(Dothiorella gregaria Sacc. )无显著的抑菌作用(P>0.05).研究结果显示,碎米莎草穗部总生物碱具有被开发为稻田用生物源农药的潜力.  相似文献   

12.
The stability of diester-diterpenoid alkaloids (DDA) from plants of the genus Aconitum L. has been studied in different solvents and pH buffers. The HPLC/ESIMS method for analysing the concentration of DDA was established and DDA's decomposition products were elucidated by HPLC/ESI-MS/MS(n). In different solvents, e.g. dichloromethane, ether, methanol and distilled water, the decomposition pathways of DDA are quite different and their difference in stabilities depends on the difference of their structures, in which substituents at the N atom and substituents at C-3 are different. The pyrolytic products of DDA, such as deacetoxy aconitine-type alkaloids, have been observed in the above solvents, whereas 8-methoxy-14-benzoyl aconitine-type alkaloids have been obtained only in methanol. Furthermore, the experimental results demonstrate that the stability of DDA depends on pH values of the buffer. Aconine as hydrolysate has been only found in pH 10.0 buffer, and the other hydrolysates and the pyrolyzates of DDA, such as benzoylaconine and deacetoxy aconitine, have been observed in all pH aqueous solutions. The decomposition pathways of DDA in buffers are related to the substituent on the C-3 position. The decomposition pathway of aconitine is similar to that of mesaconitine, but different from that of hypaconitine.  相似文献   

13.
The phytochemical investigation from the leaves of Duguetia pycnastera Sandwith (Annonaceae) led to the isolation and identification of ten compounds: nine isoquinoline-derived alkaloids, including five aporphines, anonaine, isopiline, O-methylisopiline, nornuciferine, and norstephalagine; three oxoaporphines, O-methylmoschatoline, liriodenine, and lysicamine; and one tetrahydroprotoberberine, isocorypalmine; in addition, one C11-terpene lactone known as loliolide. The isolated compounds (except for O-methylmochatoline and lysicamine) are described for the first time in the species and their chemophenetics relationships were discussed. The occurrence of loliolide is reported for the first time in the Duguetia. The structure elucidation of these compounds was established by extensive analyzes of 1D and 2D NMR spectroscopy in combination with MS. The NMR spectroscopic data for norstephalagine and isocorypalmine were reviewed.  相似文献   

14.
Several Longitarsus flea beetle species sequester pyrrolizidine alkaloids acquired from their Asteraceae and Boraginaceae host plants. We carried out feeding and injection experiments using radioactively labeled pyrrolizidine alkaloids to investigate the physiological mechanisms of uptake, metabolism and storage of alkaloids in adult beetles. We examined six Longitarsus species belonging to different phylogenetic clades in a comparative approach. All species that accepted pyrrolizidine alkaloids in a preceding food choice study showed the ability both to store pyrrolizidine alkaloid N-oxides and to metabolize tertiary pyrrolizidine alkaloids into their N-oxides. Regardless of whether the beetles' natural host plants contain pyrrolizidine alkaloids or not, these species were found to possess an oxidizing enzyme. This oxygenase appears to be specific to pyrrolizidine alkaloids: [3H]Atropine and [14C]nicotine, two alkaloids not related to pyrrolizidine alkaloids, were neither stored nor N-oxidized by any of the tested species. One species, L. australis, that strictly avoids pyrrolizidine alkaloids behaviorally, exhibited a lack of adaptations to pyrrolizidine alkaloids on a physiological level as well. After injection of tertiary [14C]senecionine, beetles of this species neither N-oxidized nor stored the compounds, in contrast to L. jacobaeae, an adapted species that underwent the same treatment. L. jacobaeae demonstrated the same efficiency in N-oxidation and storage when fed or injected with tertiary [14C]senecionine.Communicated by G. Heldmaier  相似文献   

15.
The extraction and characterization of the essential oils (EO) from Satureja montana L., Myristica fragrans H. and Cymbopogon flexuosus and the determination of their antibacterial and antioxidant activities were achieved. The EO were identified by gas chromatography/mass spectrometry and quantified by gas chromatography using a flame ionization detector. The antibacterial potential against Escherichia coli and Staphylococcus aureus was evaluated by cell susceptibility assays and by scanning electron microscopy. The antioxidant activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl assay, by β-carotene bleaching and by determining the reducing power. Borneol (36·18%), γ-terpineol (12·66%) and carvacrol (11·07%) were the principal components in the EO from S. montana, and sabinene (49·23%) and α-pinene (13·81%) were found in the EO from M. fragrans. Geranial (59·66%) and neral (38·98%) isomers were the only major components in the EO from C. flexuosus. The EO from S. montana was effective against E. coli, with minimum inhibitory and bactericidal concentrations (MIC and MBC) of 6·25 µl ml−1, whereas bactericidal potential against both was observed for the EO from M. fragrans; MIC = 6·25 µl ml−1 for S. aureus and MBC = 12·5 µl ml−1 for E. coli. A significant protective role on lipid substrates in the β-carotene bleaching assay was seen for the EO from S. montana and M. fragrans. Overall, such EO can be promising agents against pathogenic bacteria and for protecting biomolecules during oxidative stress.  相似文献   

16.
宁夏枸杞属(茄科)一新种和一新变种   总被引:3,自引:0,他引:3  
描述了宁夏茄科枸杞属一新种小叶黄果枸杞和一新变种密枝枸杞。小叶黄果枸杞与宁夏枸杞相接近,但前者枝条成"之"字形曲折,叶片较小,条形、条状披针形、条状倒披针形或狭椭圆形,花1~2朵与叶一起簇生于短枝顶端,花萼杯状或筒状,常2浅裂,裂片边缘无毛;花冠筒部与冠檐近等长,雄蕊着生于花冠筒的喉部,花丝连同花冠无毛或在基部仅被稀疏短柔毛,浆果扁球形或椭圆球形,常为淡黄色,近透明,长6~10mm,直径6~8mm,种子5~8枚而与后者明显不同。在外部形态上,小叶黄果枸杞与新疆枸杞和土库曼枸杞也比较接近,但新疆枸杞和土库曼枸杞的枝条不成"之"字形曲折,花常2~3朵或更多与叶一起簇生于短枝顶端,花冠筒部长约为檐部裂片长的2倍,雄蕊着生于花冠筒的近中部,浆果红色。尤其是土库曼枸杞的花萼为宽钟形,常4~5裂,花冠裂片边缘有短而稀疏的缘毛而明显有异于小叶黄果枸杞。宁夏枸杞的变种密枝枸杞与原变种的区别在于前者植株分枝多而密,叶片小,狭长椭圆形、倒披针形或匙形,长1~1.8cm,宽1.5~2.5mm;雄蕊着生于花冠喉部,长短不等,其中两枚较短,其余3枚较长,花丝连同花冠无毛或在基部仅被稀疏短柔毛;浆果卵球形或椭圆形,长5~8mm,直径3~6mm,淡紫色,近透明,多汁,味甜,种子2~4粒。  相似文献   

17.
Euphrasia includes perennial or annual green parasitic plants, and has a disjunct bipolar distribution except for one transtropical connection across the high mountains of Oceania. The disjunction is coupled with strikingly contrasting patterns of morphological diversity between the southern and northern hemispheres, making it an exciting model to study processes of evolutionary diversification which shaped present floras. We inferred the relationships among 51 species representing 14 of the 15 sections of the genus based on nrDNA ITS and cpDNA trnL intron, trnL-trnF and atpB-rbcL intergenic spacers. Maximum parsimony and Bayesian inference support monophyly of the genus and of several intrageneric groups characterized by morphology, ploidy level, and geographic range. Molecular phylogenetic dating using Bayesian “relaxed” clock methods suggests that the earliest Euphrasia radiations occurred minimum 11–8 Mya with bipolarity being achieved 7–5 Mya. Biogeographic analyses using explicit model-based approach inferred Eurasia as an ancestral area for the genus. The most parsimonious reconstruction found by a dispersal-vicariance analysis requires 17 dispersals to account for the current biogeographic pattern and supports Eurasian origin for Euphrasia. Both long-distance dispersal and across land vicariance can be invoked to explain the diversification in the genus, which experienced rapid radiations driven by new ecological opportunities of the late Pliocene and Pleistocene but also retained a set of local endemic or relict species of an earlier origin.  相似文献   

18.
Protaetia brevitarsis seulensis (Kolbe) has been temporarily registered as a food material by the Ministry of Food and Drug Safety of Korea (MFDS). The current study aimed to discover small antithrombotic molecules from this edible insect. Five indole alkaloids, 5‐hydroxyindolin‐2‐one ( 1 ), (1R,3S)‐1‐methyl‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid ( 2 ), (1S,3S)‐1‐methyl‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid ( 3 ), (3S)‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylic acid ( 4 ) and L‐tryptophan ( 5 ), were isolated from the insect. Among them, compounds 1 and 2 prolonged aPTT and PT and impaired thrombin and FXa generation on HUVEC surface. Moreover, these compounds inhibited platelet aggregation. Antithrombotic effects of compounds 1 and 2 were further confirmed in pre‐clinical models of pulmonary embolism and arterial thrombosis. Collectively, these results demonstrated that compounds 1 and 2 could be effective antithrombotic agents and serve as new scaffolds for the development of antithrombotic drug.  相似文献   

19.
Castilleja holmgrenii is described from several collections made in the Sierra Madre Occidental in southeast Sinaloa and adjacent southwest Durango, Mexico. The new species is a member of subgenus and sectionCastilleja. This apparently rare species is presently known from two small, geographically restricted populations. Also provided are a list of theCastilleja species of this region with notes on their status and distribution, a key for their identification, and nomenclatural and taxonomic notes concerning some of the species.  相似文献   

20.
Plant galls are widely distributed, and their extracts are used in traditional medicine worldwide. Traditional remedies containing extracts of plant galls in China, India and some African countries have effective in the treatment of various pathologies. To open a new promising procedure for screening bioactive compounds from plant galls, standardized plant materials were generated in vitro and used for phytochemical and biological investigations. Methanol aqueous chloroform and hexane extracts of Nicotiana tabacum leafy galls induced by Rhodococcus fascians were used to evaluate phenolic and flavonoid contents, and to investigate antioxidant activity by 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging and ferric reducing antioxidant/power assays and anti‐inflammatory activity by the lipoxygenase inhibition assay. Infection by R. fascians modifies significantly the phytochemical profile of N. tabacum as well as its biological properties. The total polyphenolic content was increased (120–307%), and that of flavonoids was reduced (20–42.5%). Consequently, antioxidant and anti‐inflammatory activities of non‐infected tobacco extracts are significantly modified compared to plants treated with leafy gall extracts. This shows that infection by R. fascians favoured the production of anti‐inflammatory and antioxidant compounds in N. tabacum. The study indicates the benefit of plant galls used in traditional medicines against various pathologies.  相似文献   

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