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Sample records for allelochemicals

  1. Allelochemicals

    Energy Technology Data Exchange (ETDEWEB)

    Waller, G.R.

    1987-01-01

    This book contains 51 selections. Some of the titles are: Allelopathy: A potential cause of forest regeneration failure; Allelopathic effects on mycorrhizae: Influence on structure and dynamics of forest ecosystems; Allelopathic interference with regeneration of the allegheny hardwood forest; and Studies on the fulvic and humic acids of Minnesota peat.

  2. Mechanism and active variety of allelochemicals

    Science.gov (United States)

    Peng, S.-L.; Wen, J.; Guo, Q.-F.

    2004-01-01

    This article summarizes allelochemicals' active variety, its potential causes and function mechanisms. Allelochemicals' activity varies with temperature, photoperiod, water and soils during natural processes, with its initial concentration, compound structure and mixed degree during functional processes, with plant accessions, tissues and maturity within-species, and with research techniques and operation processes. The prospective developmental aspects of allelopathy studies in the future are discussed. Future research should focus on: (1) to identify and purify allelochemicals more effectively, especially for agriculture, (2) the functions of allelopathy at the molecular structure level, (3) using allelopathy to explain plant species interactions, (4) allelopathy as a driving force of succession, and (5) the significance of allelopathy in the evolutionary processes.

  3. Allelochemicals: Role in agriculture and forestry

    Energy Technology Data Exchange (ETDEWEB)

    Waller, G.R.

    1987-01-01

    The author reports on the nature of allelochemicals, the natural defense mechanisms of plants; looks at the mechanisms and rates of allelochemical emissions from the aggressive plant, their fate in the soil and their uptake, and translocation and mode of action within the receptive plant; examines the allelopathic phenomenon in sections covering plant-plant and plant-soil-plant interactions; plant-insect interaction; and plant-microbial and plant-animal interactions; and ideas for maintaining and increasing forest and agricultural production in the future.

  4. Fungal allelochemicals in insect pest management.

    Science.gov (United States)

    Holighaus, Gerrit; Rohlfs, Marko

    2016-07-01

    Interactions between insects and fungi are widespread, and important mediators of these interactions are fungal chemicals that can therefore be considered as allelochemicals. Numerous studies suggest that fungal chemicals can affect insects in many different ways. Here, we apply the terminology established by insect-plant ecologists for categorizing the effect of fungal allelochemicals on insects and for evaluating the application potential of these chemicals in insect pest management. Our literature survey shows that fungal volatile and non-volatile chemicals have an enormous potential to influence insect behavior and fitness. Many of them still remain to be discovered, but some recent examples of repellents and toxins could open up new ways for developing safe insect control strategies. However, we also identified shortcomings in our understanding of the chemical ecology of insect-fungus interactions and the way they have been investigated. In particular, the mode-of-action of fungal allelochemicals has often not been appropriately designated or examined, and the way in which induction by insects affects fungal chemical diversity is poorly understood. This review should raise awareness that in-depth ecological studies of insect-fungus interactions can reveal novel allelochemicals of particular benefit for the development of innovative insect pest management strategies.

  5. Autotoxicity in Pogostemon cablin and their allelochemicals

    Directory of Open Access Journals (Sweden)

    Yan Xu

    2015-04-01

    Full Text Available Abstract The effects of allelochemicals and aqueous extracts from different Pogostemon cablin (Blanco Benth., Lamiaceae, parts and rhizosphere soil on growth parameters, leaf membrane peroxidation and leaf antioxidant enzymes were investigated in patchouli. P. cablin seedlings were incubated in solutions containing allelochemicals and aqueous extracts from different patchouli parts and its rhizosphere soil at several concentrations. Firstly, the growth parameters were significantly reduced by the highest concentration of leaves, roots and stems extracts (p < 0.05. As compared to the control, plant height was reduced by 99.8% in the treatment with leaves extracts (1:10. The malondialdehyde content increased greatly when patchouli seedlings were subject to different concentrations of leaves, roots and stems extracts; meanwhile, the superoxide dismutase and peroxidase activities showed an increase trend at the low concentration, followed by a decline phase at the high concentration of roots and leaves extracts (1:10. What's more, leaves and roots extracts had a more negative effect on patchouli growth than stems extracts at the same concentrations. Secondly, the total fresh mass, root length and plant height were greatly reduced by the highest strength of soil extracts. Their decrements were 22.7, 74.9, and 33.1%, respectively. Thirdly, growth parameters and enzymatic activities varied considerably with the kinds of allelochemicals and with the different concentrations. Plant height, root length and total fresh weight of patchouli were greatly reduced by p-hydroxybenzoic acid (200 μM, and their decrements were 77.0, 42.0 and 70.0%, respectively. Finally, three useful measures on reducing the autotoxicity during the sustainable patchouli production were proposed.

  6. Benzoxazinoid allelochemicals are absorbed and metabolized in mammals

    DEFF Research Database (Denmark)

    B. Adhikari, Khem; Laursen, Bente Birgitte; Lærke, Helle Nygaard

    2014-01-01

    Benzoxazinoids are a group of naturally occurring bioactive allelochemicals mostly found in cereal plants. In addition to their allelopathic effects, benzoxazinoids contain a range of health-protecting effects and pharmacological properties. The presence of these chemicals in mature cereal grains...

  7. Mathematical Modeling of Allelopathy. III. A Model for Curve-Fitting Allelochemical Dose Responses

    OpenAIRE

    Liu, Li; An, Min; Johnson, Ian R.; Lovett, John V.

    2003-01-01

    Bioassay techniques are often used to study the effects of allelochemicals on plant processes, and it is generally observed that the processes are stimulated at low allelochemical concentrations and inhibited as the concentrations increase. A simple empirical model is presented to analyze this type of response. The stimulation-inhibition properties of allelochemical-dose responses can be described by the parameters in the model. The indices, p% reductions, are calculated to assess the alleloc...

  8. Antialgal effects of five individual allelochemicals and their mixtures in low level pollution conditions.

    Science.gov (United States)

    Zuo, Shengpeng; Zhou, Shoubiao; Ye, Liangtao; Ding, Ying; Jiang, Xiaofeng

    2016-08-01

    An effective, environmentally friendly, and eco-sustainable approach for removing harmful microalgae is exploiting the allelopathic potential of aquatic macrophytes. In this study, we simulated field pollution conditions in the laboratory to investigate algal inhibition by allelochemicals, thereby providing insights into field practices. We tested five allelochemicals, i.e., coumarin, ρ-hydroxybenzoic acid, protocatechuic acid, stearic acid, and ρ-aminobenzenesulfonic acid, and a typical green alga, Chlorella pyrenoidosa, under two conditions. In the unpolluted treatment, individual allelochemicals had strong algal inhibition effects, where coumarin and ρ-hydroxybenzoic acid had greater potential for algal inhibition than protocatechuic acid, stearic acid, and ρ-aminobenzenesulfonic acid based on the 50 % inhibitory concentration. However, when two or three allelochemicals were mixed in specific proportions, the algal inhibition rate exceeded 80 %, thereby indicating allelopathic synergistic interactions. Mixtures of four or five allelochemicals had weak effects on algal inhibition, which indicated antagonistic interactions. Furthermore, the presence of low lead pollution significantly reduced the antialgal potential of individual allelochemicals, whereas the allelopathic synergistic interactions with mixtures between two or three allelochemicals were changed into antagonistic effects by low pollution. In particular, the allelopathic antagonistic interactions between four or five allelochemicals were increased by pollution. The allelopathic performance of these five allelochemicals may depend on various factors, such as the chemical species, mixture parameters, and algal strain. Thus, we found that low level pollution reduced the allelopathic inhibition of microalgae by allelochemicals. Therefore, the control of algae by the direct addition of allelochemicals should consider various environmental factors.

  9. Allelochemicals in the rhizosphere soil of Euphorbia himalayensis.

    Science.gov (United States)

    Liu, Quan; Lu, Dengxue; Jin, Hui; Yan, Zhiqiang; Li, Xiuzhuang; Yang, Xiaoyan; Guo, Hongru; Qin, Bo

    2014-08-27

    Weed infestation has been known to cause considerable reductions in crop yields, thereby hindering sustainable agriculture. Many plants in genus Euphorbia affect neighboring plants and other organisms by releasing chemicals into the environment. In view of the serious threat of weeds to agriculture, the allelochemicals of Euphorbia himalayensis and their allelopathic effects were investigated. The extract of root exudates from rhizosphere soil exhibited allelopathic activities against crops (wheat, rape, and lettuce) and grasses (Poa annua, Festuca rubra, and red clover). Bioassay-guided fractionation and isolation from the root extract of E. himalayensis led to the characterization of two ellagic acid derivatives and a jatrophane diterpene, which observably showed phytotoxic activities against lettuce, Festuca arundinacea, and F. rubra. They were further confirmed by ultra-performance liquid chromatography-tandem mass spectrometry to have concentrations of 3.6, 3.8, and 8.99 nmol/g in the rhizospere soil, respectively. Bioassay indicated that the combination of the allelochemicals could be selective plant growth regulator in agriculture.

  10. Effects of Allelochemicals from Ficus microcarpaon Chlorella pyrenoidosa

    Directory of Open Access Journals (Sweden)

    Zhongyang Jiang

    2014-08-01

    Full Text Available This study was performed in order to isolate and identify unknown allelochemicals from Ficus microcarpa, and to investigate the inhibitory to bloom-forming of green alga Chlorella pyrenoidosa. Through gradient elution, fraction C2, whose inhibition of alga growth in diverse extracts was the strongest was shown to cause significant reductions of maximum quantum yield, as well as electron transport rates of C. pyrenoidosa. The study data also showed that the increase of fraction C2 concentration decreased the activity of total superoxide dismutase (SOD, but increased the activities of catalase (CAT and malondialdehyde (MDA content. These results demonstrate that the active fraction C2 not only induced the photoinhibition or photodamage of PSII reaction centers, but also triggered the synthesis of reactive oxygen species which may change cell membrane penetrability, thereby leading to the eventual death of C. pyrenoidosa. Furthermore, the gas chromatography/mass spectrometry (GC/MS analyses showed that the most potential allelochemical in active fraction C2 was 2-Propyl phenol, which may exhibit potent allelopathy.

  11. Allelochemical, Eudesmane-Type Sesquiterpenoids from Inula falconeri

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    Kazuo N. Watanabe

    2010-03-01

    Full Text Available We have identified through bioassay guided isolation an allelochemical, eudesmane-type sesquiterpeniod, 3β-caffeoxyl-β1,8α-dihydroxyeudesm-4(15-ene(1,from an endemic plant species growing in the Himalayas. In our search for the bioactive subfraction, the hexane one was highly significant, showing 100% inhibition of lettuce seed growth at 100 ppm while other subfractions (chloroform, ethyl acetate, butanol and water exhibited inhibitory to stimulatory allelopathic effects. The bioactive hexane subfraction was subjected to chromatographic techniques, using lettuce seeds (Lactuca sativa as indicator species to reveal the bioactive allelopathic fraction. This resulted in the isolation of compound 1, whose structure was elucidated through NMR techniques. The compound presented 92.34% inhibitory effect on the growth of lettuce at 500 ppm. Further field level experiments may help develop an environmentally friendly herbicide from this lead.

  12. Current Trends in the Studies of Allelochemicals for Their Application in Practice

    Directory of Open Access Journals (Sweden)

    Arsen V.Viter

    2015-06-01

    Full Text Available The allelochemicals have been largely used in agriculture, forestry, landscape design and ornamental plant growing for many decades. However, there is a lack of the comprehensive studies, where existing publications are analyzed and synthesized with regards to the theoretic aspects for such usage. The objective of this paper was to systemize the advances in the research on allelochemicals’ application in practice. Numerous novel methodological propositions have risen recently. We classified them into the physical, chemical, biological, biotechnological and cropgrowing approaches. The allelochemicals consist of the wide diversity of the substances according to their chemical nature. Among these substances we outlined, firstly, the unidentified plant exudates and the products of green manuring, secondly, the chemically characterized or purified substances, which include alcohols, organic acids, aliphatic compounds, aromatic, alicyclic and nitrogen-contain organic compounds. Several groups of the biotic sources of allelochemicals were described: dicotyledonous and monocotyledonous plants, particularly under their colonization by non-pathogenic strains of Fusarium oxysporum, marine flora and fungi, which exhibit the herbicidal activity. Different targets of the allelochemical application were listed in the paper and they were categorized into several groups: higher flora, animals, unicellular and multi-cellular fungi. We concluded that there is lack of the modern multifaceted knowledge bases for the information about the allelochemical application. Those knowledge bases must be useful in order to choose the appropriate biological method for solving each particular problem of plant cultivation. To that end we systemized the results of current investigation about the usage of allelochemicals in practice.

  13. Effect of Allelochemicals of Chinese—fir root extracted by supercritical CO2 extraction on Chinese fir

    Institute of Scientific and Technical Information of China (English)

    LINSi-zu; CAOGuang-qiu; DULing; WANGAi-ping

    2003-01-01

    Allelochemicals of Chinese-fir root was extracted by technology of supercritical CO2 extraction under orthogonal experiment design, and it was used to analyze allelopathic activity of Chinese-fir through bioassay of seed germination, The results showed that as to the available rate of allelochemicals, the pressure and temperature of extraction were the most im-portant factors, The allelochemicals of Chinese-fir root extracted by pure CO2 and ethanol mixed with CO2 have different al-lelopathic activities to seed germination, and the allelochemicals extracted by ethanol mixed with CO2 had stronger inhibitory effects on seed Qermination than that extracted by pure CO2.

  14. Momilactone A and B as allelochemicals from moss Hypnum plumaeforme: first occurrence in bryophytes.

    Science.gov (United States)

    Nozaki, Hiroshi; Hayashi, Ken-ichiro; Nishimura, Naoki; Kawaide, Hiroshi; Matsuo, Akihiko; Takaoka, Daisuke

    2007-12-01

    Momilactones A (1) and B (2), which have been identified as phytoalexins in rice, were isolated from extracts of the moss Hypnum plumaeforme. This is the first isolation and identification of momilactones as allelochemicals from a bryophyte. H. plumaeforme produces considerable amounts of momilactones (isolated yield: 8.4 mg/Kg plant for 1; 4.2 mg/Kg for 2). EtOAc extracts from H. plumaeforme and 2 showed growth inhibitory activity against angiosperms, moss, and liverwort plants. On the other hand, the growth of H. plumaeforme was insensitive to its extract and 2. Our finding suggests that momilactones play an important role as allelochemicals in this moss.

  15. Mimosine, the Allelochemical from the leguminous tree Leucaena leucocephala, selectively enhances cell proliferation in dinoflagellates.

    Science.gov (United States)

    Yeung, Patrick K K; Wong, Francis T W; Wong, Joseph T Y

    2002-10-01

    Mimosine, the allelochemical from the leguminous tree Leucaena leucocephala, is toxic to most terrestrial animals and plants. We report here that while mimosine inhibits major phytoplankton groups, it enhances cell proliferation in dinoflagellates. On addition to coastal seawater samples, mimosine is able to confer a growth advantage to dinoflagellates. The use of mimosine will promote the isolation and culture of this group of phytoplankton.

  16. Mathematical Modeling of Allelopathy. III. A Model for Curve-Fitting Allelochemical Dose Responses

    Science.gov (United States)

    Liu, De Li; An, Min; Johnson, Ian R.; Lovett, John V.

    2003-01-01

    Bioassay techniques are often used to study the effects of allelochemicals on plant processes, and it is generally observed that the processes are stimulated at low allelochemical concentrations and inhibited as the concentrations increase. A simple empirical model is presented to analyze this type of response. The stimulation-inhibition properties of allelochemical-dose responses can be described by the parameters in the model. The indices, p% reductions, are calculated to assess the allelochemical effects. The model is compared with experimental data for the response of lettuce seedling growth to Centaurepensin, the olfactory response of weevil larvae to α-terpineol, and the responses of annual ryegrass (Lolium multiflorum Lam.), creeping red fescue (Festuca rubra L., cv. Ensylva), Kentucky bluegrass (Poa pratensis L., cv. Kenblue), perennial ryegrass (L. perenne L., cv. Manhattan), and Rebel tall fescue (F. arundinacea Schreb) seedling growth to leachates of Rebel and Kentucky 31 tall fescue. The results show that the model gives a good description to observations and can be used to fit a wide range of dose responses. Assessments of the effects of leachates of Rebel and Kentucky 31 tall fescue clearly differentiate the properties of the allelopathic sources and the relative sensitivities of indicators such as the length of root and leaf. PMID:19330111

  17. Mathematical Modeling of Allelopathy. III. A Model for Curve-Fitting Allelochemical Dose Responses.

    Science.gov (United States)

    Liu, De Li; An, Min; Johnson, Ian R; Lovett, John V

    2003-01-01

    Bioassay techniques are often used to study the effects of allelochemicals on plant processes, and it is generally observed that the processes are stimulated at low allelochemical concentrations and inhibited as the concentrations increase. A simple empirical model is presented to analyze this type of response. The stimulation-inhibition properties of allelochemical-dose responses can be described by the parameters in the model. The indices, p% reductions, are calculated to assess the allelochemical effects. The model is compared with experimental data for the response of lettuce seedling growth to Centaurepensin, the olfactory response of weevil larvae to alpha-terpineol, and the responses of annual ryegrass (Lolium multiflorum Lam.), creeping red fescue (Festuca rubra L., cv. Ensylva), Kentucky bluegrass (Poa pratensis L., cv. Kenblue), perennial ryegrass (L. perenne L., cv. Manhattan), and Rebel tall fescue (F. arundinacea Schreb) seedling growth to leachates of Rebel and Kentucky 31 tall fescue. The results show that the model gives a good description to observations and can be used to fit a wide range of dose responses. Assessments of the effects of leachates of Rebel and Kentucky 31 tall fescue clearly differentiate the properties of the allelopathic sources and the relative sensitivities of indicators such as the length of root and leaf.

  18. Cyanobacterial Toxins as Allelochemicals with Potential Applications as Algaecides, Herbicides and Insecticides

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    Fernando G. Noriega

    2008-05-01

    Full Text Available Cyanobacteria (“blue-green algae” from marine and freshwater habitats are known to produce a diverse array of toxic or otherwise bioactive metabolites. However, the functional role of the vast majority of these compounds, particularly in terms of the physiology and ecology of the cyanobacteria that produce them, remains largely unknown. A limited number of studies have suggested that some of the compounds may have ecological roles as allelochemicals, specifically including compounds that may inhibit competing sympatric macrophytes, algae and microbes. These allelochemicals may also play a role in defense against potential predators and grazers, particularly aquatic invertebrates and their larvae. This review will discuss the existing evidence for the allelochemical roles of cyanobacterial toxins, as well as the potential for development and application of these compounds as algaecides, herbicides and insecticides, and specifically present relevant results from investigations into toxins of cyanobacteria from the Florida Everglades and associated waterways.

  19. Maxillary palps can mediate taste rejection of plant allelochemicals by caterpillars.

    Science.gov (United States)

    Glendinning, J I; Valcic, S; Timmermann, B N

    1998-07-01

    All caterpillars possess a pair of maxillary palps that "drum" the surface of foods during feeding. These chemosensory organs contain over 65% of a caterpillar's taste receptor cells, but their functional significance remains largely unknown. We examined their role in rejection of plant allelochemicals, using the tobacco hornworm (Manduca sexta) as a model insect and an extract from a plant species (Grindelia glutinosa) as a model stimulus. We selected this system because hornworms reject foods containing Grindelia extract, and because preliminary studies indicated that their maxillary palps respond to this extract. We hypothesized that Grindelia extract elicits rejection through stimulating: (1) olfactory receptor cells, (2) taste receptor cells, (3) oral mechanoreceptors, and/or (4) a postingestive response mechanism. Our results were consistent only with hypothesis 2: caterpillars approached Grindelia-treated diets without apparent hesitation, but rejected it within 6 s of initiating biting; Grindelia-treated solutions stimulated taste receptor cells in the maxillary palp, but not the other gustatory chemosensilla; and ablating the maxillary palps eliminated rejection of Grindelia-treated diets. Our results demonstrate that taste receptor cells in the maxillary palps mediate rejection of Grindelia extract, and provide the first direct evidence for the role of maxillary palps in rejection of plant allelochemicals.

  20. [Effects of allelochemical EMA isolated from Phragmites communis on algal cell membrane lipid and ultrastructure].

    Science.gov (United States)

    Li, Feng-min; Hu, Hong-ying; Chong, Yun-xiao; Men, Yu-jie; Guo, Mei-ting

    2007-07-01

    In order to reveal the antialgal mechanisms of allelochemicals, effects of the allelochemical eathyl-2-methyl acetoacetate (EMA) on cell membrane lipid and ultrastructure of Chlorella pyrenoidosa, Microcystis aeruginosa and Chlorella vulagaris were studied in this paper. The lipid fatty acids of the algal membrane were isolated following the Bligh and Dye method and quantified by gas chromatograph/mass spectrometry. The ultrastructure of algal cells was observed with TEM. The results showed that EMA increased the contents of linolenic acid and linolic acid with increment of 14%, while decreased the content of myristic acid and cetylic acid in C. pyrenoidosa, membrane. The content of unsaturated fatty acids C18:1 and C18:2 increased 12% and 10% in M. aeruginosa with the addition of EMA, while the content of saturated fatty acids C18:0 and C16:0 decreased. EMA showed no significant change in the fatty acid composition in C. vulagaris under the experiment condition. EMA broke off cell wall of C. pyrenoidosa and M. aeruginosa. EMA damaged the cell membrane and the inclusion of algal cell leaked out. Nuclear and mitochondrial structure was damaged with the addition of EMA. EMA showed no significant change in the ultrastructure of C. vulgaris.

  1. Fate of allelochemicals in the soil Destino de aleloquímicos no solo

    Directory of Open Access Journals (Sweden)

    Ribas Antonio Vidal

    1997-06-01

    Full Text Available Allelochemicals are compounds released by one plant or plant residues that may have a negative or positive effect on other plant. The importance of allelopathy was extensively explored during the past three decades, with the work concentrating in the extraction and identification of the chemicals, and demonstration of activity in petry dish experiments. These compounds interact in the soil environment similarly as herbicides and are subject to processes of degradation such as microbial degradation, oxidation, and photolysis, and processes of removal or transfer, such as volatilization and adsorption. The objective of this review was to access the fate of allelochemicals in the soil environment to help to find strategies to increase its activity. The activity of allelochemical is limited in time (because of slow release from the donor material and in space (because of the interaction with the environment. Demonstration of allelopathy should include the fate of the proposed chemical in the soil environment, presenting studies of degradation and removal processes.Aleloquímicos são compostos liberados por plantas ou seus resíduos e que podem ter efeito negativo ou positivo em outra planta. A importância da alelopatia foi estudada intensamente nas últimas três décadas, sendo que a maioria dos trabalhos abordou a extração e identificação dos compostos e, demonstração de seus efeitos em experimentos realizados em placas de petri. Estes químicos interagem no ambiente assim como os herbicidas e estão sujeitos aos processos de degradação por decomposição microbiana, fotólise e oxidação e, processos de remoção ou transferência como volatilização e adsorção. O objetivo desta revisão de literatura foi estudar o destino de aleloquímicos no ambiente para auxiliar na definição de estratégias para aumentar sua atividade. A atividade dos aleloquímicos é limitada pelo tempo (devido a liberação lenta do material doador e pelo

  2. Oxidative damage and cell-programmed death induced in Zea mays L. by allelochemical stress.

    Science.gov (United States)

    Ciniglia, Claudia; Mastrobuoni, Francesco; Scortichini, Marco; Petriccione, Milena

    2015-05-01

    The allelochemical stress on Zea mays was analyzed by using walnut husk washing waters (WHWW), a by-product of Juglans regia post-harvest process, which possesses strong allelopathic potential and phytotoxic effects. Oxidative damage and cell-programmed death were induced by WHWW in roots of maize seedlings. Treatment induced ROS burst, with excess of H2O2 content. Enzymatic activities of catalase were strongly increased during the first hours of exposure. The excess in malonildialdehyde following exposure to WHWW confirmed that oxidative stress severely damaged maize roots. Membrane alteration caused a decrease in NADPH oxidase activity along with DNA damage as confirmed by DNA laddering. The DNA instability was also assessed through sequence-related amplified polymorphism assay, thus suggesting the danger of walnut processing by-product and focusing the attention on the necessity of an efficient treatment of WHWW.

  3. ISOLATION AND CHARACTERISATION OF A NEW ALLELOCHEMICAL FROM PARTHENIUM HYSTEROPHORUS L.

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    R. N. Yadava* and Shirin Khan

    2013-01-01

    Full Text Available Parthenium hysterophorus L. is commonly known as “Gajar ghas" in Hindi and belongs to family Composite. It is an annual herb erect up to 1.5 m in hight. Its stems is branched and covered with trichomes. Its leaves are pale green, branched and covered with soft fine hairs. In Homoeopathy system, allergies caused by Parthenium can be treated by a drug prepared from Parthenium. Root decoction is useful in dysentery. In the present paper, we report the isolation and structurel elucidation of a new allelochemical identified (I as 3 , 5, 7, 4′ tetrahydroxy-3'-methoxyflavone-3-O--L-galactopyranosyl-(1→3-O--D-arabinopyranosyl-7-O--L-rhamnopyranoside alongwith two known compounds Lutexin (II and Cirsilineol (III from methanolic extract of the stems of this plant by several colour reactions, chemical degradations and spectral analysis.

  4. Crabgrass (Digitaria sanguinalis) allelochemicals that interfere with crop growth and the soil microbial community.

    Science.gov (United States)

    Zhou, Bin; Kong, Chui-Hua; Li, Yong-Hua; Wang, Peng; Xu, Xiao-Hua

    2013-06-05

    Three chemicals, veratric acid, maltol, and (−)-loliolide, were isolated from crabgrass and their structures were identified by spectroscopic analysis. The chemicals were detected in crabgrass root exudates and rhizosphere soils, and their concentrations ranged from 0.16 to 8.10 μg/g. At an approximate concentration determined in crabgrass root exudates, all chemicals significantly inhibited the growth of wheat, maize, and soybean and reduced soil microbial biomass carbon. Phospholipid fatty acid profiling showed that veratric acid, maltol, and (−)-loliolide affected the signature lipid biomarkers of soil bacteria, actinobacteria, and fungi, resulting in changes in soil microbial community structures. There were significant relationships between crop growth and soil microbes under the chemicals' application. Chemical-specific changes in the soil microbial community generated negative feedback on crop growth. The results suggest that veratric acid, maltol, and (−)-loliolide released from crabgrass may act as allelochemicals interfering with crop growth and the soil microbial community.

  5. CHEMICAL EXAMINATION OF A NEW ALLELOCHEMICAL FROM STEMS OF GLOSSOCARDIA BOSVALLIA DC.

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    Dr. R. N. Yadava et al

    2012-10-01

    Full Text Available Glossocardia bosvallia DC.1-3 belongs to family Composite which is commonly known as “Patthar-suva or seri” in Hindi. It is found almost throughout in India and Deccan Peninsula. It is a small annual herb, 10-20 cm tall. The tribal inhabitants of western Maharashtra use a decoction of the plant as febrifuge. It has a bitter taste and fennel like odor. Besides serving as a medicinal plant Pithari plant is also used in culinary purposes. In the present paper, we report the isolation and structural elucidation of a new allelochemical 5,6,7,4′, tetrahydroxy 3-methoxy flavone -7-O--D xylopyranosyl (1→4-O--D- glucopyranoside (A which showed antiviral activity , alongwith two known compounds 6, 4΄-dimethoxy-5, 7-dihydroxy-flavone (B and Isoorientin (C from methanolic extract of the stems of this plant.

  6. The Allelochemical MDCA Inhibits Lignification and Affects Auxin Homeostasis1[OPEN

    Science.gov (United States)

    Steenackers, Ward; Corneillie, Sander; Van de Wouwer, Dorien; Zažímalová, Eva

    2016-01-01

    The phenylpropanoid 3,4-(methylenedioxy)cinnamic acid (MDCA) is a plant-derived compound first extracted from roots of Asparagus officinalis and further characterized as an allelochemical. Later on, MDCA was identified as an efficient inhibitor of 4-COUMARATE-CoA LIGASE (4CL), a key enzyme of the general phenylpropanoid pathway. By blocking 4CL, MDCA affects the biosynthesis of many important metabolites, which might explain its phytotoxicity. To decipher the molecular basis of the allelochemical activity of MDCA, we evaluated the effect of this compound on Arabidopsis thaliana seedlings. Metabolic profiling revealed that MDCA is converted in planta into piperonylic acid (PA), an inhibitor of CINNAMATE-4-HYDROXYLASE (C4H), the enzyme directly upstream of 4CL. The inhibition of C4H was also reflected in the phenolic profile of MDCA-treated plants. Treatment of in vitro grown plants resulted in an inhibition of primary root growth and a proliferation of lateral and adventitious roots. These observed growth defects were not the consequence of lignin perturbation, but rather the result of disturbing auxin homeostasis. Based on DII-VENUS quantification and direct measurement of cellular auxin transport, we concluded that MDCA disturbs auxin gradients by interfering with auxin efflux. In addition, mass spectrometry was used to show that MDCA triggers auxin biosynthesis, conjugation, and catabolism. A similar shift in auxin homeostasis was found in the c4h mutant ref3-2, indicating that MDCA triggers a cross talk between the phenylpropanoid and auxin biosynthetic pathways independent from the observed auxin efflux inhibition. Altogether, our data provide, to our knowledge, a novel molecular explanation for the phytotoxic properties of MDCA. PMID:27506238

  7. Physiological and biochemical effects of allelochemical ethyl 2-methyl acetoacetate (EMA) on cyanobacterium Microcystis aeruginosa.

    Science.gov (United States)

    Hong, Yu; Hu, Hong-Ying; Li, Feng-Min

    2008-10-01

    The physiological and biochemical effects of an allelochemical ethyl 2-methyl acetoacetate (EMA) isolated from reed (Phragmites communis) on bloom-forming cyanobacterium, Microcystis aeruginosa, were investigated. EMA significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The metabolic indices (represented by esterase and total dehydrogenase activities), the cellular redox status (represented by the level of reactive oxygen species (ROS)), and the oxidative damage index (represented by the content of malondialdehyde (MDA), the product of membrane lipid peroxidation) were used to evaluate the physiological and biochemical changes in M. aeruginosa after EMA exposure. Esterase activity in M. aeruginosa did not change (P>0.05) after 2 h of exposure to EMA, but increased greatly after 24 and 48 h (PEMA exposure (>0.5 mg L(-1)) resulted in a remarkable loss of total dehydrogenase activity in M. aeruginosa after 4 h (PEMA caused a great increase in ROS level of the algal cells. At high EMA concentration (4 mg L(-1)), the ROS level was remarkably elevated to 1.91 times as much as that in the controls after 2 h. Increases in the ROS level also occurred after 24 and 48 h. The increase in lipid peroxidation of M. aeruginosa was dependent upon EMA concentration and the exposure time. After 40 h of exposure, the MDA content at 4 mg L(-1) of EMA reached approximately 3.5 times (PEMA; the increased metabolic activity perhaps reflects the fact that the resistance of cellular response system to the stress from EMA is initiated during EMA exposure, and the oxidative damage induced by EMA via the oxidation of ROS may be an important factor responsible for the inhibition of EMA on the growth of M. aeruginosa.

  8. [Effects of allelochemical isolated from Phragmites communis on algal membrane permeability].

    Science.gov (United States)

    Li, Feng-Min; Hu, Hong-Ying; Chong, Yun-Xiao; Guo, Mei-Ting; Men, Yu-Jie

    2007-11-01

    Efflux of K+, Mg2+, Ca2+ ions from algal cells as signals of cell membrane permeability, inductively coupled plasma mass spectrometry (ICP-MS) as detection method of ions, the present research investigated effects of allelochemical eathyl-2-methyl acetoacetate (EMA) isolated from Phragmites communis on cell membrane permeability of Microcystis aeruginosa, Chlorella pyrenoidosa and Chlorella vulagaris. The results showed that, when the cells were boiled for 10 min and the membrane was destroyed absolutely, the K+ efflux of M. aeruginosa and C. pyrenoidosa were 1.45 and 1.59 microg x (10(9) cell) (-1), respectively. When the concentration of EMA was 2 mg x L(-1), the K+ efflux of M. aeruginosa and C. pyrenoidosa were 1.38 and 1.40 microg x (10(9) cell)(-1), respectively. The K+ efflux of M. aeruginosa and C. pyrenoidosa reached 1.44 and 1.58 microg x (10(9) cell)(-1) while the EMA was 4 mg x L(-1). When the concentrations were 2 mg x L(-1) or 4 mg x L(-1) the K+ efflux reached more than 95% of the total ion amount in M. aeruginosa and C. pyrenoidosa cells. But when EMA concentration was 4 mg x L(-1), K+ efflux of C. vulagaris was 0.64 microg x (10(9) cell)(-1), which was only 31.5% of total K+ amount in C. vulagaris. Effects EMA on efflux of Mg2+ and Ca2+ were similar to those of K+. The results indicated that EMA destroyed the cell membrane of M. aeruginosa and C. pyrenoidosa but not C. vulagaris. This is one of the mechanisms of EMA species-selective antialgal.

  9. ESTRESSE OXIDATIVO EM CÉLULAS VEGETAIS MEDIANTE ALELOQUÍMICOS OXIDATIVE STRESS IN VEGETABLE CELLS MEDIATED BY ALLELOCHEMICALS

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    Gustavo Dias de Almeida

    2008-06-01

    Full Text Available A alelopatia é uma interação entre dois organismos, onde um componente é afetado e o outro permanece estável. Esta interação pode ser fonte de descobertas para novos compostos fitotóxicos naturais com baixa toxicidade aos organismos não alvos de controle. A maior parte dos aleloquímicos são metabólitos secundários como os terpenóides, compostos fenólicos e ácido cianídrico, entre outros. A atuação dos aleloquímicos é variada e afeta um grande número de reações bioquímicas, resultando em diferentes modificações fisiológicas nas plantas, como na atividade enzimática, divisão e estrutura de células, permeabilidade das membranas e captação de íons, culminado na redução ou inativação da germinação e crescimento das plantas. Efeitos dos aleloquímicos sobre a fotossíntese e respiração tem sido melhor caracterizados, embora vários trabalhos tenham demonstrado a atuação desses compostos no estresse oxidativo, resultando em um aumento da produção de espécies reativas de oxigênio, os quais em concentrações elevadas são danosos às células. Dessa forma, o conhecimento dos mecanismos de atuação dos aleloquímicos é necessário para o desenvolvimento de técnicas de manejo sustentável na agricultura.Allelopathy is an interaction among two organisms, where one of that is affected and the other stays stable. It can be source for discoveries of new natural phytotoxic compounds with low toxicity to the organisms that are not target of control. Most of the allelochemicals are secondary metabolites like terpenoids, phenolic compounds, organic cyanides and longchain fatty acids. The performance of the allelochemicals can be different according the situations, and it affects a great number of biochemical reactions, resulting in different physiologic modifications in the plants. Allelochemicals could affect different pathways, like, the enzymatic activity, division and structure of cells, permeability of the

  10. Chemical stress induced by heliotrope (Heliotropium europaeum L.) allelochemicals and increased activity of antioxidant enzymes.

    Science.gov (United States)

    Abdulghader, Kalantar; Nojavan, Majid; Naghshbandi, Nabat

    2008-03-15

    The aims of this study were to evaluate the allelopathic potential of heliotrope on some biochemical processes of dodder. The preliminary experiments revealed that the effect of aqueous extract of leaves of heliotrope is higher than its seeds and roots. So, the aqueous extract of leaves was used in remaining experiments. Leaf extracts of 5 g powder per 100 mL H2O inhibited the germination of dodder seeds up to 95% and that of radish up to 100%. While, the aqueous extract of vine leaves which is a non-allelopathic plant did not have any inhibitory effect on these seeds. Vine leaf was used as a control to show that the inhibitory effect of heliotrope is due to an inhibitory compound but not due to the concentration. The leaf extract of heliotrope at 0.0, 0.1, 1.0, 2, 3, 4 and 5 g powder per 100 mL H2O reduced the radish seedling growth from 14 cm to about 0.5 cm and that of dodder from 7.5 cm to about 0.25 cm. The effects of heliotrope allelochemicals on some physiological and biochemical processes of radish was also Investigated. The activity of auxin oxidase increased in leaves and roots of radish. Suggesting that the reduced radish growth is due to the decreased active auxin levels in its leaves and roots. The activity of alpha-amylase was reduced, so reduction of starch degradation and lack of respiratory energy is the prime reason of germination inhibition in dodder and radish seeds. The level of soluble sugars increased. This is an indication of reduction of the activity of some respiratory enzymes and reduced consumption of these sugars. Proline levels were also increased, indicating that, the chemical stress is induced by leaf extract. Finally, the activities of GPX and CAT which are antioxidant enzymes were increased, along with increased extract concentration. These finding shows that the chemical stress induced by leaf extract produces super oxide (O2*) and H2O2, which is neutralized to H2O and O2 by these enzymes.

  11. A novel cytochrome P450 CYP6AB14 gene in Spodoptera litura (Lepidoptera: Noctuidae) and its potential role in plant allelochemical detoxification

    Science.gov (United States)

    Cytochrome P450 monooxygenases (P450) play a prominent role in the adaptation of insects to host plant chemical defenses. To investigate the potential role of P450s in adaptation of the lepidopteran pest Spodoptera litura to host plant allelochemicals, an expressed sequence data set derived from 6th...

  12. Dissolved Organic Matter (DOM) From Different Composts: Comparative Study Of Properties And Allelochemical Effects On Horticultural Plants

    Science.gov (United States)

    Traversa, A.; Loffredo, E.; Gattullo, C. E.; Senesi, N.

    2009-04-01

    Dissolved organic matter (DOM) from compost has a major role in numerous chemical and biological processes occurring in the bulk substrate or compost amended soil, and can exert allelochemical effects on plant germination and growth. The objectives of this study were: (i) to investigate comparatively the main properties of three DOM fractions isolated from a green compost (DOMGC), a mixed compost (DOMMC) and a green coffee compost (DOMGCC), and (ii) to evaluate their allelochemical effects on the germination and early growth of two horticultural plants of worldwide interest such as tomato and lettuce. The DOM was extracted from each compost with distilled water (1/10 w/v) under mechanical shaking for 15 min. The suspension was then centrifuged at 6000 rpm for 15 min and filtered sequentially through filters with decreasing particle size retention (from 11 to 0.45 μm). Each DOM sample was characterized by means of pH, electrical conductivity, total organic carbon (TOC), E4/E6 ratio, fluorescence and FT IR spectroscopies and HPLC analysis. Comparative evaluation of the three DOM samples indicated the occurrence of significant differences among them. In particular, the pH value was similar and close to neutrality for DOMMC and DOMGC, whereas it resulted alkaline (pH 8.3) for DOMGCC. The EC values were also similar (about 3.2 mS/cm) for DOMMC and DOMGC and almost half value for DOMGCC. The TOC content, the E4/E6 ratio, the ɛ280 value and the humification index followed the same order: DOMGCC>DOMMC>DOMGC. The fluorescence analysis of the three DOM samples showed the presence of a common fluorophore unit associated to simple aromatic units such as phenolic-like, hydroxy-substituted benzoic and cinnamic acid derivatives. The peak wavelengths observed in the fluorescence emission, excitation and synchronous scan spectra of DOMGCC were generally higher than those of the two other DOM samples, which can be ascribed to a more extended aromatic system of the former. The FT

  13. Plant bioassay to assess the effects of allelochemicals on the metabolome of the target species Aegilops geniculata by an NMR-based approach.

    Science.gov (United States)

    D'Abrosca, Brigida; Scognamiglio, Monica; Fiumano, Vittorio; Esposito, Assunta; Choi, Young Hae; Verpoorte, Robert; Fiorentino, Antonio

    2013-09-01

    A metabolomic-based approach for the study of allelopathic interactions in the Mediterranean area is proposed using Aegilops geniculata Roth (Poaceae), a Mediterranean herbaceous plant, as test species. Its metabolome has been elucidated by 1D and 2D NMR experiments. Hydroponic plant cultures of A. geniculata were treated with specific compounds of known allelopathic potential: catechol, coumarin, p-coumaric acid, p-hydroxybenzoic acid, ferulic acid and juglone. The metabolic variations due to the presence of allelochemicals have been analyzed and measured. All of the compounds showed the strongest effects at the highest concentration, with coumarin and juglone as the most active compounds, causing an increase of several metabolites. The metabolome changes in test plants confirmed the allelochemicals' reported modes of action. The results demonstrated that the proposed method is a promising tool. It can be applied to plant extracts, making it possible to evidence the metabolites responsible for the activity, as well as their mechanisms of action.

  14. The use of bio-guided fractionation to explore the use of leftover biomass in Dutch flower bulb production as allelochemicals against weeds.

    Science.gov (United States)

    Wahyuni, Dinar S C; van der Kooy, Frank; Klinkhamer, Peter G L; Verpoorte, Rob; Leiss, Kirsten

    2013-04-17

    A major problem in flower bulb cultivation is weed control. Synthetic herbicides are mainly used, although they cause a range of problems, and integrated weed control through application of naturally occurring allelochemicals would be highly desirable. Flower bulb production creates large amounts of leftover biomass. Utilizing this source for weed control may provide new applications of the bulb crops. We therefore screened 33 flower bulb extracts for allelochemical activity against weeds. Several methanol and chloroform extracts were observed to inhibit germination and growth of Senecio vulgaris L. and Lolium perenne L., as representatives of di- and mono-cotyledonous weeds, respectively. Narciclasine was identified as the bioactive compound in Narcissus. The extract of Amaryllis belladonna L. was equally active, but did not contain any narciclasine. Bioassay-guided fractionation of the A. belladonna extract resulted in the identification of lycorine as the bio-active compound. The IC₅₀ measured for radicle growth inhibition was 0.10 µM for narciclasine and 0.93 µM for lycorine, compared to 0.11 mM of chlorpropham, a synthetic herbicide. Therefore, the leftover biomass from the spring bulb industry represents an interesting potential source for promising allelochemicals for further studies on weed growth inhibition.

  15. Identification and Characterization of CYP9A40 from the Tobacco Cutworm Moth (Spodoptera litura), a Cytochrome P450 Gene Induced by Plant Allelochemicals and Insecticides.

    Science.gov (United States)

    Wang, Rui-Long; Staehelin, Christian; Xia, Qing-Qing; Su, Yi-Juan; Zeng, Ren-Sen

    2015-09-18

    Cytochrome P450 monooxygenases (P450s) of insects play crucial roles in the metabolism of endogenous and dietary compounds. Tobacco cutworm moth (Spodoptera litura), an important agricultural pest, causes severe yield losses in many crops. In this study, we identified CYP9A40, a novel P450 gene of S. litura, and investigated its expression profile and potential role in detoxification of plant allelochemicals and insecticides. The cDNA contains an open reading frame encoding 529 amino acid residues. CYP9A40 transcripts were found to be accumulated during various development stages of S. litura and were highest in fifth and sixth instar larvae. CYP9A40 was mainly expressed in the midgut and fat body. Larval consumption of xenobiotics, namely plant allelochemicals (quercetin and cinnamic acid) and insecticides (deltamethrin and methoxyfenozide) induced accumulation of CYP9A40 transcripts in the midgut and fat body. Injection of dsCYP9A40 (silencing of CYP9A40 by RNA interference) significantly increased the susceptibility of S. litura larvae to the tested plant allelochemicals and insecticides. These results indicate that CYP9A40 expression in S. litura is related to consumption of xenobiotics and suggest that CYP9A40 is involved in detoxification of these compounds.

  16. Identification and Characterization of CYP9A40 from the Tobacco Cutworm Moth (Spodoptera litura, a Cytochrome P450 Gene Induced by Plant Allelochemicals and Insecticides

    Directory of Open Access Journals (Sweden)

    Rui-Long Wang

    2015-09-01

    Full Text Available Cytochrome P450 monooxygenases (P450s of insects play crucial roles in the metabolism of endogenous and dietary compounds. Tobacco cutworm moth (Spodoptera litura, an important agricultural pest, causes severe yield losses in many crops. In this study, we identified CYP9A40, a novel P450 gene of S. litura, and investigated its expression profile and potential role in detoxification of plant allelochemicals and insecticides. The cDNA contains an open reading frame encoding 529 amino acid residues. CYP9A40 transcripts were found to be accumulated during various development stages of S. litura and were highest in fifth and sixth instar larvae. CYP9A40 was mainly expressed in the midgut and fat body. Larval consumption of xenobiotics, namely plant allelochemicals (quercetin and cinnamic acid and insecticides (deltamethrin and methoxyfenozide induced accumulation of CYP9A40 transcripts in the midgut and fat body. Injection of dsCYP9A40 (silencing of CYP9A40 by RNA interference significantly increased the susceptibility of S. litura larvae to the tested plant allelochemicals and insecticides. These results indicate that CYP9A40 expression in S. litura is related to consumption of xenobiotics and suggest that CYP9A40 is involved in detoxification of these compounds.

  17. The Garlic Allelochemical Diallyl Disulfide Affects Tomato Root Growth by Influencing Cell Division, Phytohormone Balance and Expansin Gene Expression

    Science.gov (United States)

    Cheng, Fang; Cheng, Zhihui; Meng, Huanwen; Tang, Xiangwei

    2016-01-01

    Diallyl disulfide (DADS) is a volatile organosulfur compound derived from garlic (Allium sativum L.), and it is known as an allelochemical responsible for the strong allelopathic potential of garlic. The anticancer properties of DADS have been studied in experimental animals and various types of cancer cells, but to date, little is known about its mode of action as an allelochemical at the cytological level. The current research presents further studies on the effects of DADS on tomato (Solanum lycopersicum L.) seed germination, root growth, mitotic index, and cell size in root meristem, as well as the phytohormone levels and expression profile of auxin biosynthesis genes (FZYs), auxin transport genes (SlPINs), and expansin genes (EXPs) in tomato root. The results showed a biphasic, dose-dependent effect on tomato seed germination and root growth under different DADS concentrations. Lower concentrations (0.01–0.62 mM) of DADS significantly promoted root growth, whereas higher levels (6.20–20.67 mM) showed inhibitory effects. Cytological observations showed that the cell length of root meristem was increased and that the mitotic activity of meristematic cells in seedling root tips was enhanced at lower concentrations of DADS. In contrast, DADS at higher concentrations inhibited root growth by affecting both the length and division activity of meristematic cells. However, the cell width of the root meristem was not affected. Additionally, DADS increased the IAA and ZR contents of seedling roots in a dose-dependent manner. The influence on IAA content may be mediated by the up-regulation of FZYs and PINs. Further investigation into the underlying mechanism revealed that the expression levels of tomato EXPs were significantly affected by DADS. The expression levels of EXPB2 and beta-expansin precursor were increased after 3 d, and those of EXP1, EXPB3 and EXLB1 were increased after 5 d of DADS treatment (0.41 mM). This result suggests that tomato root growth may be

  18. The garlic allelochemical diallyl disulfide affects tomato root growth by influencing cell division, phytohormone balance and expansin gene expression

    Directory of Open Access Journals (Sweden)

    Fang Cheng

    2016-08-01

    Full Text Available Diallyl disulfide (DADS is a volatile organosulfur compound derived from garlic (Allium sativum L., and it is known as an allelochemical responsible for the strong allelopathic potential of garlic. The anticancer properties of DADS have been studied in experimental animals and various types of cancer cells, but to date, little is known about its mode of action as an allelochemical at the cytological level. The current research presents further studies on the effects of DADS on tomato (Solanum lycopersicum L. seed germination, root growth, mitotic index and cell size in root meristem, as well as the phytohormone levels and expression profile of auxin biosynthesis genes (FZYs, auxin transport genes (SlPINs and expansin genes (EXPs in tomato root. The results showed a biphasic, dose-dependent effect on tomato seed germination and root growth under different DADS concentrations. Lower concentrations (0.01-0.62 mM of DADS significantly promoted root growth, whereas higher levels (6.20-20.67 mM showed inhibitory effects. Cytological observations showed that the cell length of root meristem was increased and that the mitotic activity of meristematic cells in seedling root tips was enhanced at lower concentrations of DADS. In contrast, DADS at higher concentrations inhibited root growth by affecting both the length and division activity of meristematic cells. However, the cell width of the root meristem was not affected. Additionally, DADS increased the IAA and ZR contents of seedling roots in a dose-dependent manner. The influence on IAA content may be mediated by the up-regulation of FZYs and PINs. Further investigation into the underlying mechanism revealed that the expression levels of tomato EXPs were significantly affected by DADS. The expression levels of EXPB2 and beta-expansin precursor were increased after 3 d, and those of EXP1, EXPB3 and EXLB1 were increased after 5 d of DADS treatment (0.41 mM. This result suggests that tomato root growth

  19. Colony induction and growth inhibition in Desmodesmus quadrispina (Chlorococcales) by allelochemicals released from the filamentous alga Uronema confervicolum (Ulotrichales).

    Science.gov (United States)

    Leflaive, Joséphine; Lacroix, Gérard; Nicaise, Yvan; Ten-Hage, Loïc

    2008-06-01

    In biofilms, the competition between microorganisms for light, nutrients and space is extreme. Moreover, planktonic algae can be considered as competitors insofar as they decrease the available light for the benthic algae. One of the strategies employed by microorganisms to eliminate competitors is the release of inhibiting compounds, a process known as allelopathy. Here we demonstrate that a benthic/epiphytic alga, Uronema confervicolum, produces allelopathic compounds that induce oxidative stress and growth inhibition in the planktonic Desmodesmus quadrispina. Some of these compounds can also trigger the formation of colony in D. quadrispina. As colonies have higher sedimentation rates than unicells, their induction by U. confervicolum might decrease shading. This study is the first report of colony induction in the context of alga-alga interaction. Our results also suggest the implication of mitogen-activated protein (MAP) kinases in the transduction of the signal leading to the formation of reactive oxygen species in the cells. A comparison with allelochemicals from another planktonic green alga, Monoraphidium aff. dybowski, emphasizes the specificity of colony induction by U. confervicolum, in contrast with oxidative stress which is induced by several compounds. The reciprocal production of inhibiting compounds by D. quadrispina makes this interaction an interesting example of co-evolution between two microorganisms belonging to different compartments of the ecosystem.

  20. Effects of a novel allelochemical ethyl 2-methyl acetoacetate (EMA) on the ultrastructure and pigment composition of cyanobacterium Microcystis aeruginosa.

    Science.gov (United States)

    Hong, Yu; Huang, Jing-Jing; Hu, Hong-Ying

    2009-10-01

    Allelochemical ethyl 2-methyl acetoacetate (EMA) can significantly inhibit the growth of bloom-forming Microcystis aeruginosa. In order to assess the implication of the damage of EMA on the algal photosynthetic apparatus, the effects of EMA on the algal ultrastructure and pigment composition were investigated. At initial exposure time to EMA (0-40 h), algal allophycocyanin, phycoerythrin and carotenoid degraded firstly; chlorophyll a increased, especially by 47% in the algae exposed to 2 mg L(-1) of EMA; phycocyanin was not significantly affected; lipid bodies increased remarkably. After 40 h of EMA exposure, chlorophyll a decreased gradually, especially by 45% in the algae exposed to 4 mg L(-1) of EMA; lipid bodies greatly reduced but cyanophycin granules accumulated; thylakoid structures were dissolved or disappeared with the presence of numerous vacuoles. These results showed that all ophycocyanin, phycoerythrin and carotenoid were more sensitive to EMA than other pigments, the cells of M. aeruginosa was stressed by EMA with the occurrence of cyanophycin granules and the photosynthesis pigments and ultrastructure of M. aeruginosa were quickly destroyed by EMA with exposure time increasing.

  1. Allelochemicals of Pinus halepensis as drivers of biodiversity in Mediterranean open mosaic habitats during the colonization stage of secondary succession.

    Science.gov (United States)

    Fernandez, Catherine; Santonja, Mathieu; Gros, Raphael; Monnier, Yogan; Chomel, Mathilde; Baldy, Virginie; Bousquet-Mélou, Anne

    2013-02-01

    The Mediterranean region is recognized as a global biodiversity hotspot. However, over the last 50 years or so, the cessation of traditional farming has given way to strong afforestation at the expense of open habitats. Pinus halepensis Miller, known to synthesize a wide range of secondary metabolites, is a pioneer expansionist species colonizing abandoned agricultural land that present high species richness. Here, laboratory bioassays were used to study the potential impact of P. halepensis on plant diversity through allelopathy, and the role of microorganisms in these interactions. Germination and growth of 12 target species naturally present in fallow farmlands were tested according to concentration of aqueous extracts obtained from shoots of young pines (aged about 5 years), with or without the presence of soil microorganisms (autoclaved or natural soil). Under the highest concentrations and autoclaved soil, more than 80 % of target species were germination and/or growth-inhibited, and only two species were non-sensitive. Under more natural conditions (lower extracts concentrations and natural soil with microorganisms), only 50 % of species were still inhibited, one was non-sensitive, and five were stimulated. Thus, microorganisms alter the expression of allelochemicals released into the ecosystem, which highlights their key role in chemical plant-plant interactions. The results of allelopathic experiments conducted in the lab are consistent with the community patterns observed in the field. These findings suggest that allelopathy is likely to shape vegetation composition and participate to the control of biodiversity in Mediterranean open mosaic habitats.

  2. Physiological and biochemical mechanisms of allelopathy mediated by the allelochemical extracts of Phytolacca latbenia (Moq.) H. Walter.

    Science.gov (United States)

    Ullah, Nazif; Haq, Ihsan Ul; Safdar, Naila; Mirza, Bushra

    2015-10-01

    In allelopathy, one plant suppresses the growth and development of other plant/plants by negatively affecting a variety of physiological and biochemical reactions. We checked the effects of methanolic extracts (allelochemical extracts) of Phytolacca latbenia (Moq.) H. Walter on antioxidant enzyme activities such as peroxidases (PODs), super oxide dismutases (SODs) and catalase (CAT) and on total protein contents (TPC), cellular injury (CI), and malondialdehyde (MDA) in the germinating seeds of Brassica napus L. (dicot) and Triticum aestivum L. (monocot). Both the crude methanolic extract root (CMER) and crude methanolic extract aerial (CMEA) of P. latbenia at 10000 ppm significantly reduced the POD activity in both the test seeds. The activity of SODs was significantly decreased by both CMER and CMEA in B. napus germinating seeds. A linear increase in the activity of CAT, CI, and MDA contents was found in both the test seeds with the increasing concentrations of CMEA and CMER, while TPC of the germinating seeds was found decreased. It is inferred that both the CMEA and CMER inhibited/delayed the seed germination, reduced the seedling growth by affecting a variety of biochemical and physiological attributes, and also caused cellular membrane injury in the germinating seeds of both the monocot and dicot seeds.

  3. Isolation and Identification of Potential Allelochemicals from Aerial Parts of Avena fatua L. and Their Allelopathic Effect on Wheat.

    Science.gov (United States)

    Liu, Xingang; Tian, Fajun; Tian, Yingying; Wu, Yanbing; Dong, Fengshou; Xu, Jun; Zheng, Yongquan

    2016-05-11

    Five compounds (syringic acid, tricin, acacetin, syringoside, and diosmetin) were isolated from the aerial parts of wild oats (Avena fatua L.) using chromatography columns of silica gel and Sephadex LH-20. Their chemical structures were identified by means of electrospray ionization and high-resolution mass spectrometry as well as (1)H and (13)C nuclear magnetic resonance spectroscopic analyses. Bioassays showed that the five compounds had significant allelopathic effects on the germination and seedling growth of wheat (Triticum aestivum L.). The five compounds inhibited fresh wheat as well as the shoot and root growth of wheat by approximately 50% at a concentration of 100 mg/kg, except for tricin and syringoside for shoot growth. The results of activity testing indicated that the aerial parts of wild oats had strong allelopathic potential and could cause different degrees of influence on surrounding plants. Moreover, these compounds could be key allelochemicals in wild-oat-infested wheat fields and interfere with wheat growth via allelopathy.

  4. Responses of enzymatic antioxidants and non-enzymatic antioxidants in the cyanobacterium Microcystis aeruginosa to the allelochemical ethyl 2-methyl acetoacetate (EMA) isolated from reed (Phragmites communis).

    Science.gov (United States)

    Hong, Yu; Hu, Hong-Ying; Xie, Xing; Li, Feng-Min

    2008-08-25

    Macrophytic allelochemicals are considered an environment-friendly and promising alternative to control algal bloom. However, studies examining the potential mechanisms of inhibitory allelochemicals on algae are few. The allelochemical ethyl 2-methyl acetoacetate (EMA), isolated from reed (Phragmites communis), was a strong allelopathic inhibitor on the growth of Microcystis aeruginosa. EMA-induced antioxidant responses were investigated in the cyanobacterium M. aeruginosa to understand the mechanism of EMA inhibition on algal growth. The activities of enzymatic antioxidants superoxide dismutase (SOD) and catalase (CAT), and the contents of non-enzymatic antioxidants reduced glutathione (GSH) and ascorbic acid (AsA) of M. aeruginosa cells were analyzed after treatments with different concentrations of EMA. Exposure of M. aeruginosa to EMA caused changes in enzyme activities and contents of non-enzymatic antioxidants in different manners. The decrease in SOD activity occurred first after 4 h of EMA exposure, and more markedly after 40 h. CAT activity did not change after 4 h of EMA exposure, but increased obviously after 40 h. The contents of AsA and GSH were increased greatly by EMA after 4 h. After 60 h, low EMA concentrations still increased the CAT activity and the contents of AsA and GSH, but high EMA concentrations started to impose a marked suppression on them. EMA increased dehydroascorbate (DHAsA) and oxidized glutathione (GSSG) contents during all exposure times. After 60 h, the regeneration rates of AsA and GSH (represented by the AsA/DHAsA ratio and GSH/GSSG ratio, respectively) were reduced by high EMA concentrations. These results suggest that the activation of CAT and the availability of AsA and GSH at early exposure are important to counteract the oxidative stress induced by EMA, and the inactivation of SOD may be crucial to the growth inhibition of M. aeruginosa by EMA.

  5. Molecular analysis of CYP321A1, a novel cytochrome P450 involved in metabolism of plant allelochemicals (furanocoumarins) and insecticides (cypermethrin) in Helicoverpa zea.

    Science.gov (United States)

    Sasabe, Masataka; Wen, Zhimou; Berenbaum, May R; Schuler, Mary A

    2004-09-01

    Cytochrome P450 monooxygenases play a significant role in the detoxification of hostplant allelochemicals and synthetic insecticides in Lepidoptera. In the corn earworm Helicoverpa zea, a noctuid of considerable economic importance, metabolisms of xanthotoxin, a toxic furanocoumarin, and alpha-cypermethrin, an insecticide, are mediated by at least one P450 with a catalytic site capable of accepting both substrates. To further the characterization of P450s in this species, we have cloned three full-length cDNAs encoding two CYP4M subfamily members and a novel CYP321A subfamily member. RNA analyses have demonstrated that the CYP321A1 gene is highly induced (51-fold) in larval midguts in response to xanthotoxin but not cypermethrin. Both CYP4M genes are expressed at negligible levels that are not increased by xanthotoxin or cypermethrin. Baculovirus-mediated expression of the full-length CYP321A1 cDNA has demonstrated that the CYP321A1 protein metabolizes xanthotoxin and angelicin, like the CYP6B1 protein in the furanocoumarin specialist Papilio polyxenes, and alpha-cypermethrin, like the CYP6B8 protein previously characterized in H. zea. In contrast, the CYP4M7 protein does not metabolize xanthotoxin at any detectable level. We conclude that at least two xanthotoxin-inducible P450s from highly divergent subfamilies (CYP6B and CYP321A) contribute to the resistance of H. zea larvae to toxic furanocoumarins and insecticides. Genomic PCR analysis indicates that the CYP321A1 gene has evolved independently from the CYP6B genes known to be present in this insect.

  6. Study on the allelochemicals of inhibiting Mikania micrantha growth from Cuscuta japonica%抑制薇甘菊生长的日本菟丝子化感物质研究

    Institute of Scientific and Technical Information of China (English)

    李秋玲; 肖辉林

    2012-01-01

    采用制备型高效液相色谱、重结晶等方法从有害植物日本菟丝子(Cuscuta japonica Choisy)的水浸液有机萃取物中分离出能显著抑制薇甘菊(Mikania micrantha H.B.K.)种子萌发的化感物质,并采用核磁共振(1HNMR、13CNMR)法、质谱(MS)法等对其结构进行分析和鉴定.结果表明:能显著抑制薇甘菊种子萌发的日本菟丝子化感物质为桂皮酸(cinnamic acid)和3-苯基丙酸(3-phenylpropanoic acid).这2种化合物在菟丝子属的植物中属首次分离鉴定.这2种化感物质具有开发为生物源农药(如除草剂)的潜力.研究结果为人侵植物薇甘菊的防治提供了参考依据,也为日本菟丝子的开发利用开辟了一条新途径.%In this study, allelochemicals, which has the marked inhibition effects on the seed germination of Mikania micrantha H. B. K., were extracted and separated from Cuscuta japonica Choisy through recrystal and their structures were identified through the analyses of 'HNMR, 13CNMR and MS. The study indicates that the allelochemicals are cinnamic acid and 3-phenylpropanoic acid. These two compounds are the first time to be seperated and identified from the custuta plants. It is supposed that these two allelochemicals should be developed as new-type biological pesticides (such as herbicide). The results provide reference for the prevention and control of Mikania micrantha invasion, and for the new way to exploit and utilize C. japonica.

  7. Bioavailability of Allelochemicals in Soil

    Science.gov (United States)

    2008-02-27

    knapweed species has been noted (Goslee et at., 2001; Grant et al., 2003; Hierro and Callaway, 2003). Yet, very little is known about the sorption of...Environmental Science & Technology 31:321-326. Hierro , J.L., and R.M. Callaway. 2003. Allelopathy and exotic plant invasion. Plant and Soil 256:29-39

  8. 化感物质对白藜种子萌发及抗氧化物酶活性的影响%Effects of Allelochemicals on Seed Germination and Seedling Antioxidant Enzyme Activity of Chenopodium album

    Institute of Scientific and Technical Information of China (English)

    李巧峡; 李腾腾; 高加来; 赵庆芳; 杨宁

    2012-01-01

    Chenopodium album is a common weed of wheat and other arable crops. Ferulic acid, vanillic acid, theobromine, theophylline, luteolin and quercetin are used to test their allelopathic effects on seed germination, seedling growth and antioxidant enzyme activity of C. album. The present study provides theoretical guidance for the biological control of C. album. Results show that six allelochemicals have significant allelopathic effects on seed germination, seedling growth and the activity of antioxidant enzymes. The effects are obviously related with the concentration and species of allelochemicals. Seed germination of C. album is significantly inhibited under 1 mmol ·L-1 of tested allelochemicals except vanillic acid and theobromine, while seed germination is promoted at lower concentrations. Superoxide dismutase (SOD) and catalase (CAT) activities initially have an increasing tendency, followed by a decreasing trendency. Perox-idase (POD) activity shows an opposite trendency with allelochemical (ferulic acid, theophylline, quercetin and luteolin) concentrations increasing. Ferulic acid, theophylline, quercetin and luteolin at 1 mmol ·L-1 obviously reduce SOD and CAT activities, while significantly increase POD activity except luteolin.%白藜(Chenopodium album)是小麦(Triticum aestivum)和其他耕地作物以及果园里常见杂草.试验选用阿魏酸、香草酸、可可碱、茶碱、木樨草素、槲皮黄素6种化感物质,通过对白藜种子萌发、幼苗生长及抗氧化酶活性的影响进行化感作用研究,为其生物防治提供理论指导.结果表明:6种化感物质对白藜种子萌发、幼苗生长及抗氧化物酶活性有明显的影响,这种影响效应与化感物质的种类及浓度明显相关.当6种化感物质的浓度为l mmol·L-1时,除香草酸与可可碱外,其余均使白藜种子萌发受到抑制,其中茶碱、槲皮黄素和木樨草素表现出显著的抑制作用(P<0.05);而6种化感物质在较低

  9. Concurrently inhibitory and allelopathic effects of allelochemicals secreted by Myriophyllum spicatum on growth of blue-green algae; Hozakinofusamo ga hoshutsushita areropashi busshitsu no aisorui ni taisuru fukugo sayo oyobi areropashi koka no hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Nakai, S.; Inoue, Y.; Hosomi, M.; Murakami, A. [Tokyo Univ. of Agriculture and Technology, Tokyo (Japan)

    1998-10-10

    This paper describes effects of allelochemicals secreted by Myriophyllum spicatum on growth of blue-green algae. In order to propose an effective growth inhibitory method of blue-green algae with less impact on the ecosystem, biological interaction (allelopathy) between large aquatic plants and algae was investigated. Pyrogallic acid, gallic acid, catechin and ellagic acid secreted by M. spicatum provided growth inhibitory effects of blue-green algae (Microcyctis aeruginosa), individually. Complex interaction and allelopathic contribution of these four polyphenols were evaluated. By comparing the actual effects with the expected values, synergetic growth inhibitory effects were recognized by adding four polyphenols at the same time. Furthermore, growth inhibitory effects were evaluated for actual culture solution of M. spicatum and simulated culture solution made by four polyphenols. As a result, it was found that these four polyphenols relate to allelopathy of M. spicatum. 25 refs., 6 figs., 4 tabs.

  10. Allelochemicals Identification in the Root and the Rhizosperic Soil of Parsley%西芹鲜根及根际区物化感物质成分鉴定

    Institute of Scientific and Technical Information of China (English)

    陈磊; 云兴福

    2012-01-01

    In order to investigate the allelochemicals in the root and the rhizosperic soil of parsley,the column chromatography and GC-MS were used to study the best allelopathy fraction of different extracts in the root and the rhizosperic soil of parsley after secondary separation. The results showed the main allelochemicals of the best allelopathy fraction of the ethanol extract in the root and the rhizosperic soil of parsley after secondary separation were 4-Dimethylamino-2-methyl-l-phenyl-butan-2-ol,8-Octadecenoic acid, methyl ester, Hexadecanoic acid, methyl ester, Octadecadienoic acid,methyl ester;the main allelochemicals of the best allelopathy fraction of the acetone extract in the root and the rhizosperic soil of parsley after secondary separation were 2-Propenoic acid, pentadecyl ester; the main allelochemicals of the best allelopathy fraction of the aqueous extract in the root and the rhizosperic soil of parsley after secondary separation were 1-Hexadecanamine, N,N-dimethyl-,Pentadecanoic acid, 14-methyl-,methyl ester,Cyclotrisiloxane, hexamethyl-, 9-Octadecenoic acid, methyl ester, ( E)-, Methyl ricinoleate, Heptadecanoic acid, 16-methyl-, methyl ester.%为探讨西芹鲜根及根际区物化感物质成分,利用柱层析法及GC-MS对西芹鲜根及根际区物不同浸提液二次层析后化感效应最佳流分进行分离鉴定.结果表明,西芹鲜根与根际区物乙醇浸提液二次层析后化感效应最佳流分的主要化感成分均为4-二甲氨基-2-甲基-1-苯基-丁-2-醇、8-十八烯酸甲酯、棕榈酸甲酯、十八烷二烯酸甲酯;西芹鲜根与根际区物丙酮浸提液二次层析后化感效应最佳流分的主要化感成分为2-丙烯酸十五烷基酯;西芹鲜根与根际区物水浸提液二次层析后化感效应最佳流分的主要化感成分为十六烷基二甲基叔胺、14-甲基十五烷酸甲酯、六甲基环三硅氧烷、(E)-9-十八烯酸甲酯、蓖麻油酸甲酯、16-甲基十七烷酸甲酯.

  11. 有机酸类化感物质的血清蛋白输运机制研究%Research the mechanism of bovine serum albumin transport organic acids allelochemicals

    Institute of Scientific and Technical Information of China (English)

    樊君; 黄凤琴; 李铭慧; 吕达; 郭明

    2015-01-01

    Affinity capillary electrophoresis( ACE) had been used to establish the analytical method of binding reactions between or-ganic acids allelochemicals and bovine serum albumin(BSA). The binding mechanisms of citric acid(CA)/sulfosalicylic acid(SA) and BSA were studied by simulating and constructing interaction system of ligand( organic)-receptor( BSA) ,and then the similari-ties and differences of the binding mechanism between different organic acids and different concentrations was compared. The results showed that the combined reactions of CA/SA with BSA were reacted to form CA-BSA and SA-BSA compounds. The mean apparent competition binding constants(KCA-BSA=(1. 82±0. 11)×104 L·mol-1,KSA-BSA=(2. 12±0. 12)×104L·mol-1)which was based on the changes of the effective mobility and determined through theoretical equation showed that the binding reactions of CA/SA-BSA were fast equilibrium reactions. The research results have illustrated the physiological effects of serum protein transporting organic acids allelochemicals and provided a theoretical reference for in-depth studying of the combined reaction of allelochemicals with biological macromolecules.%利用亲和毛细管电泳( Affinity Capillary Electrophoresis,ACE)建立有机酸类化感物质与血清白蛋白( Bo-vine serum albumin,BSA)结合反应的分析方法。模拟典型有机酸类化感物质与血清白蛋白的结合反应,构建配体(有机酸)-受体(BSA)相互作用体系,采用ACE法研究不同浓度柠檬酸(Citric Acid,CA)/磺基水杨酸( Sulfosalicylic acid,SA)与BSA的结合反应机制并比较不同有机酸作用机理异同。结果表明,有机酸类化感物质CA/SA与BSA发生结合反应形成复合物CA-BSA和SA-BSA。依据有效淌度变化,理论方程非线性拟合结合反应的表观结合常数KCA-BSA=(1.82±0.11)×104L·mol-1、KSA-BSA=(2.12±0.12)×104L·mol-1,结合反应均为快平衡反应。相关工作阐明了血清蛋白输运有机酸类化感物

  12. Photosynthetic Physiological Responses to Allelochemicals of Phyllostachys edulis in Seedlings of Camelia oleifera Abel%油茶幼苗对毛竹化感物质的光合生理响应

    Institute of Scientific and Technical Information of China (English)

    陈娟; 白尚斌; 周国模; 王懿祥; 王楠; 梁倩倩; 沈蕊

    2013-01-01

    为探讨毛竹( Phyllostachys edulis)化感物质如何影响油茶幼苗的光合生理,采用水浸提的方法,用毛竹茎叶、枯落物和根际土壤3种不同的浸提液处理油茶幼苗,以蒸馏水处理作为对照,测定不同质量浓度梯度浸提液处理下油茶幼苗的光合生理特性参数和叶绿素质量分数。结果表明:高质量浓度的毛竹浸提液显著抑制油茶幼苗叶绿素质量分数,低质量浓度则促进,其中0.02 g· mL-1的枯落物浸提液与对照相比增量为7.68%,促进作用达到了极显著水平。毛竹化感物质对油茶净光合速率、气孔导度的影响大体上表现为高质量浓度抑制、低质量浓度促进的效应。油茶幼苗光合生理参数对毛竹化感物质的响应不尽相同,高质量浓度的3种浸提液显著降低了油茶的最大净光合速率,与对照相比分别降低了27.42%、26.97%和21.25%,且抑制作用随着化感物质质量浓度的降低而逐渐减弱,直至转化为促进作用。毛竹化感物质提高了油茶的暗呼吸速率和光补偿点,而对表观量子效率无明显作用。%The experiment was conducted to study the allelopathic effects of allelochemicals of Phyllostachys edulis on photosyn-thetic physiological of Camelia oleifera Abel..With three types of aqueous extracts (stem and leaf, litter, soil), three concentration gradients (0.10, 0.05 and 0.02 g· mL-1 ) were used as different treatments, and the distilled water as the control.The chlorophyll mass fraction showed significant inhibitory effect under higher mass concentration of aqueous ex-tracts, and stimulatory effect under lower content.0.02 g· mL-1 litter extracts showed significant stimulatory effect on chlorophyll mass fraction and the stimulation rate reached 7.68%.Net photosynthesis rate and stomatal conductance were also inhibited at higher content and enhanced at lower content.Allelochemicals of P.edulis had

  13. Isolation and identification of the potential allelochemicals in the aqueous extract of yellow sweet clover (Melilotusofficinalis)%黄花草木樨水浸提液中潜在化感物质的分离、鉴定

    Institute of Scientific and Technical Information of China (English)

    邬彩霞; 刘苏娇; 赵国琦

    2014-01-01

    本研究旨在分离、鉴定黄花草木樨水浸提液中的主要化感物质。采用色谱分离、薄层分析和生物活性检测相结合的方法分离出了活性较强的化感物质组分,并通过气质联用(GC-MS)对潜在的化感物质进行了定性分析。结果表明,黄花草木樨水浸提液的乙酸乙酯相中含有多种化感物质,相对含量最高的为香豆素,相对含量较高的有6-(3-Hydroxy-but-1-enyl)-1,5,5-trimethyl-7-oxabicyclo[4,1,0]heptan-2-ol、二氢苯并吡喃酮、2,6-二叔丁基对甲酚、二溴三甲基环丙烷、磷酸三甲酯等物质;将乙酸乙酯相进一步分离得到3层混合物,上层混合物中含量相对最高的为香豆素;中层混合物中含量相对较高的有二溴三甲基环丙烷、6-(3-Hydroxy-but-1-enyl)-1,5,5-trimethy-7-oxabi-cyclo[4,1,0]heptan-2-ol、2,6-二叔丁基对甲酚、甲基环戊醇等物质;下层混合物中含量相对较高的有二溴三甲基环丙烷、甲基环戊醇、环己基溴化膦等物质。乙酸乙酯相及其分离后的各层混合物处理对多花黑麦草种子萌发和幼苗生长均具有一定的化感作用,其中,乙酸乙酯相处理对多花黑麦草化感抑制作用最强,其处理对多花黑麦草种子萌发和幼苗生长的抑制作用显著强于其分层后的各层混合物处理(P<0.05);其次是上层混合物处理,其处理对多花黑麦草种子萌发和幼苗生长的抑制作用显著强于其他2层(P<0.05);下层混合物处理对多花黑麦草的种子萌发和幼苗生长则具有明显的促进作用(P>0.05)。以上结果提示,黄花草木樨水浸提液中化感物质种类非常多,香豆素的含量最高,且香豆素含量高的组分处理对黑麦草的抑制作用就强,推测香豆素应为黄花草木樨水浸提液中的主要化感物质之一。%This study aimed to isolate and identify the main allelochemicals

  14. 辣椒根系分泌的潜力化感物质对生菜幼苗抗氧化代谢的影响%Effect of Root Exudated Potential Allelochemicals in Hot Pepper (Capsicum annumm L.) on Antioxidative Metabolism for Lettuce (Lactuca sativa L.)

    Institute of Scientific and Technical Information of China (English)

    孙海燕; 王炎

    2012-01-01

    In this paper, potted hot pepper (Capsicum annumm L.) was selected as the experiment materials, and resin adsorption extraction with gas chromatography-mass spectrometry (GC-MS) was used to determine root exudates of hot pepper to analyze potential allelochemicals. Six different concentration of exogenous suspected allelochemicals (0, 2, 4, 8, 12, 16 μg·mL-1) were applied to lettuce seed. Seed germination and seedling growth of lettuce were used to analyze allelopathy and effect on antioxidative metabolism of lettuce seedling. The results showed that 2,6-di-tertbutylphenol (2,6-DTBP), diisobutyl phthalate (DIBP) and dibutyl phthalate (DBP) were potential allelochemicals of root exudates in hot pepper, The content of glutathione (GSH) increased, and superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), polyphenol oxidase (PPO) and ascorbate peroxidase (APX) activity increased first, then decreased with increasing concentration of potential allelochemicals. Low limit concentration of allelopathic inhibition were 4, 8, and 8 μg·mL-1 for 2, 6-DTBP, DIBP and DBP, respectively, three potential allelochemicals damaged antioxidative metabolism system of lettuce seedling by decreasing the content of GSH.%以盆栽辣椒为试验材料,采用树脂吸附萃取和气质联用仪测定辣椒根系分泌物,分析、确定其中的疑似化感物质.分别使用6种(0、2、4、8、12、16 μg·mL-1)不同浓度的外源潜力化感物质处理生菜种子,通过种子发芽、幼苗生长分析其潜力化感作用,并研究其对生菜幼苗抗氧化代谢的影响.结果表明,2,6-二叔丁基苯酚(2,6-DTBP)、邻苯二甲酸二异丁酯(DIBP)和邻苯二甲酸二丁酯(DBP)为辣椒根系分泌的潜力化感物质,随三种潜力化感物质浓度的增加,生菜幼苗的谷胱甘肽(GSH)含量降低,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、多酚氧化酶(PPO)和抗坏血酸氧化酶(APX)活性先增加后降低.2,6-DTBP

  15. Physiological conjunction of allelochemicals and desert plants.

    Directory of Open Access Journals (Sweden)

    Avital Yosef Friedjung

    Full Text Available Plants exchange signals with other physical and biological entities in their habitat, a form of communication termed allelopathy. The underlying principles of allelopathy and secondary-metabolite production are still poorly understood, especially in desert plants. The coordination and role of secondary metabolites were examined as a cause of allelopathy in plants thriving under arid and semiarid soil conditions. Desert plant species, Origanum dayi, Artemisia sieberi and Artemisia judaica from two different sources (cultivar cuttings and wild seeds were studied in their natural habitats. Growth rate, relative water content, osmotic potential, photochemical efficiency, volatile composition and vital factors of allelopathy were analyzed at regular intervals along four seasons with winter showing optimum soil water content and summer showing water deficit conditions. A comprehensive analysis of the volatile composition of the leaves, ambient air and soil in the biological niche of the plants under study was carried out to determine the effects of soil water conditions and sample plants on the surrounding flora. Significant morpho-physiological changes were observed across the seasons and along different soil water content. Metabolic analysis showed that water deficit was the key for driving selective metabolomic shifts. A. judaica showed the least metabolic shifts, while A. sieberi showed the highest shifts. All the species exhibited high allelopathic effects; A. judaica displayed relatively higher growth-inhibition effects, while O. dayi showed comparatively higher germination-inhibition effects in germination assays. The current study may help in understanding plant behavior, mechanisms underlying secondary-metabolite production in water deficit conditions and metabolite-physiological interrelationship with allelopathy in desert plants, and can help cull economic benefits from the produced volatiles.

  16. Physiological conjunction of allelochemicals and desert plants.

    Science.gov (United States)

    Yosef Friedjung, Avital; Choudhary, Sikander Pal; Dudai, Nativ; Rachmilevitch, Shimon

    2013-01-01

    Plants exchange signals with other physical and biological entities in their habitat, a form of communication termed allelopathy. The underlying principles of allelopathy and secondary-metabolite production are still poorly understood, especially in desert plants. The coordination and role of secondary metabolites were examined as a cause of allelopathy in plants thriving under arid and semiarid soil conditions. Desert plant species, Origanum dayi, Artemisia sieberi and Artemisia judaica from two different sources (cultivar cuttings and wild seeds) were studied in their natural habitats. Growth rate, relative water content, osmotic potential, photochemical efficiency, volatile composition and vital factors of allelopathy were analyzed at regular intervals along four seasons with winter showing optimum soil water content and summer showing water deficit conditions. A comprehensive analysis of the volatile composition of the leaves, ambient air and soil in the biological niche of the plants under study was carried out to determine the effects of soil water conditions and sample plants on the surrounding flora. Significant morpho-physiological changes were observed across the seasons and along different soil water content. Metabolic analysis showed that water deficit was the key for driving selective metabolomic shifts. A. judaica showed the least metabolic shifts, while A. sieberi showed the highest shifts. All the species exhibited high allelopathic effects; A. judaica displayed relatively higher growth-inhibition effects, while O. dayi showed comparatively higher germination-inhibition effects in germination assays. The current study may help in understanding plant behavior, mechanisms underlying secondary-metabolite production in water deficit conditions and metabolite-physiological interrelationship with allelopathy in desert plants, and can help cull economic benefits from the produced volatiles.

  17. Resistance of tomato strains to the moth Tuta absoluta imparted by allelochemicals and trichome density Resistência de linhagens de tomateiro à traça Tuta absoluta, relacionada a aleloquímicos e à densidade de tricomas

    Directory of Open Access Journals (Sweden)

    Celso Mattes de Oliveira

    2012-02-01

    Full Text Available We examined the resistance of improved tomato strains rich in 2-tridecanone (2-TD, zingiberene (ZGB and acyl sugars (AA to the tomato moth, Tuta absoluta. We also studied whether selection for strains with higher densities of glandular trichomes, and thus presumably strains with higher concentrations of 2-tridecanone, was effective in promoting greater resistance to the moth. The TOM-584 and TOM-679 strains were used as susceptible controls, which have normal concentrations of the three allelochemicals. The improved strain TOM-687, which has a high AA content, has a widely documented resistance and was used as a standard resistant strain. The wild strain PI134417, which is resistant by means of its high 2-TD content, was also used as a standard resistant strain. The experiment was installed in a greenhouse with a completely randomized design. The wild strain PI 134417 was confirmed as being highly resistant. TOM-622 (rich in 2-TD, ZGB-703 (rich in ZGB, and TOM-687 (rich in AA showed significant reductions in the oviposition rate of the tomato moth, damage to the plants, injury to the leaflets, and the percentage of leaflets attacked in comparison with the control strains (TOM-584 and TOM-679. The levels of resistance to the moth for the TOM-622, ZGB-703, and TOM-687 strains were similar. In general, the genotypes with higher densities of glandular trichomes had greater resistance than the susceptible controls, with the strain BPX-367D-238-02 being particularly notable in its resistance.Comparou-se a efetividade de linhagens melhoradas de tomateiro, ricas em 2-tridecanona (2-TD, zingibereno (ZGB e acilaçúcares (AA, em relação aos níveis de resistência à traça-do-tomateiro Tuta absoluta. Verificaram-se, também, se linhagens selecionadas para maiores densidades de tricomas glandulares, presumivelmente com maiores níveis de 2-tridecanona, são efetivas em promover maior resistência à traça. Como testemunhas suscetíveis foram utilizadas

  18. Inhibitory Effects of 6 Macroalgae Extracts on Skeletonema costatum and Isolation of Allelochemicals%六种大型藻浸提液对中肋骨条藻的抑制及活性成分分离

    Institute of Scientific and Technical Information of China (English)

    别聪聪; 李锋民; 李媛媛; 赵雅菡; 王震宇

    2011-01-01

    g/L for Sargassum fusi forme, 1. 4 g/L for Sargassum pathen, 1. 5 g/L for Grateloupia filicina and 4. 7 g/L for Undaria pinnatifida. Enteromorpha clathrat showed a good allelopathic inhibitory potency on Skeletonema costatum growth. Among four solvent extracts of Enteromorpha clathrat, ethyl acetate extract was the most effective part, and its EC50 was 0. 08 mg/L. The components of the ethyl acetate extract was analysed by using GC-MS, and 9-octadecyne and diisobutyl phthalate took the top two largest shares, but the identfication of allelochemical of Enteromorpha clathrat needs further research.

  19. Allelopathic effects of fresh parsley root acetone extracts on Fusarium oxysporum f. sp. cucumberinum and allelochemicals identification%西芹鲜根丙酮浸提物层析流分对黄瓜枯萎病菌的化感作用以及化感物质鉴定

    Institute of Scientific and Technical Information of China (English)

    高晓敏; 王琚钢; 李杰; 马立国; 郝静; 云兴福

    2014-01-01

    为探明西芹鲜根中化感物质成分,利用柱层析法对西芹鲜根丙酮浸提液进行4次层析,每次层析后获得的流分与黄瓜枯萎病菌共培养,测定菌落直径与孢子萌发率,以化感抑制效果筛选最佳流分,然后通过GC-MS对第4次层析最佳流分中化感物质进行鉴定。结果表明,各次层析最佳流分均对黄瓜枯萎病菌菌丝生长及孢子萌发有较强抑制作用,第4次层析获得的最佳流分(RA3246、RA3344、RA9889、RA91064)对枯萎病菌菌丝生长的化感抑制效果[相对于第4次层析丙酮对照(ACK4)]分别升高至28.69%、37.83%、42.44%、33.83%,孢子萌发抑制率分别升高至50.72%、50.66%、55.02%、59.37%。通过GC-MS共鉴定出有机酸、酚、醇、酯类、杂环有机物及含氮化合物6类12种化感物质,分别为3-羟基扁桃酸、硫代乙醇酸、2,4-二叔丁基苯酚、十二烷醇、2-甲基-2-丙烯酸十三烷酯、2-丙烯酸十二烷基酯、2-丙稀酸十五烷基酯、二甲基环己酯、3,4-环氧呋喃、十六烷基二甲基叔胺、(Z)-9-十八烯酸酰胺和二丁氨腈。研究获得结果可为利用西芹提取物防控黄瓜枯萎病提供理论基础。%In field production of cucumber (Cucumis sativus), it is relatively difficult to control wilt caused by Fusarium oxysporum. However, the extent of infection is reduced by crop rotation with parsley (Apium graveloens). To identify inhibitory allelochemicals released into the soil by parsley crop, acetone extracts from fresh parsley roots were examined after a repeated series of purification (four cycles) in column chromatography (10 mm × 300 mm) using a column with silicone coating. We used a bioassay that incor-porated the various column fractions into PDA medium and co-cultured the plates with F. oxysporum f. sp. cucumberinum. By measuring colony diameter and spore germination rate, we screened the best fractions in terms of allelopathic inhibition effect and identified further

  20. The Alleviate Effect of Extracellular DNA and Protein in Maize Root Border Cells on the Allelochemical Stress from Chenopodium ambrosioides L.%玉米根边缘细胞exDNA和胞外蛋白对土荆芥化感胁迫的缓解效应

    Institute of Scientific and Technical Information of China (English)

    胡忠良; 王亚男; 马丹炜; 陈斌; 何亚强; 周健

    2015-01-01

    合物的毒性最小;土荆芥挥发油具有诱导根边缘细胞黏胶层面积增大的效应,并表现出剂量效应,当挥发油剂量达到5μL时,黏胶层相对面积与对照差异显著(P<0.05)。与对照相比,在对伞花素和α-萜品烯的作用下玉米根边缘细胞黏胶层面积变化不显著;当exDNA或胞外蛋白被DNA酶或蛋白酶降解后,根边缘细胞黏胶层相对面积缩小,细胞活性降低,其中,挥发油处理组根边缘细胞活性均在10%以下,对伞花素处理组、α-萜品烯处理组、对伞花素和α-萜品烯混合物处理组根边缘细胞活性虽然有所降低,但仍保持在80%左右。【结论】土荆芥挥发油及其主要成分对伞花素、α-萜品烯具有细胞毒性,可导致玉米根边缘细胞活性降低,根边缘细胞黏胶层中的exDNA和胞外蛋白对土荆芥挥发油、对伞花素、α-萜品烯的细胞毒性具有缓解效应,可在一定程度上缓解土荆芥的化感胁迫。%[Objective]Root border cells (RBCs) are released from the root cap as individual cells or a group of attached cells. The mucilage of root border cells acts in a manner similar to that of neutrophil extracellular traps (NETs) in defense, thus, known as border cell extracellular traps (BETs). The extracellular DNA (exDNA) and proteins are components of border cell mucilage, which have been considered to play a vital role in protecting root tip from biotic and abiotic stresses. Allelopathy is one of the successful mechanisms of exotic plant for invading. The objective of this study is to reveal the roles of the exDNA and extracellular proteins of root border cell mucilage in resistance to allelochemical stress from an invasive plant, Chenopodium ambrosioides L..[Method]Experiments were performed with maize (Zea mays L.)‘Yayu26#’, a widely grown crop in the introduced habitats of C. ambrosioides under aeroponic culture with agar medium. The developmental

  1. Effects of volatile allelochemicals from Chenopodium ambrosioides on the stoma guard cells in leaf epidermis of Vicia faba%土荆芥挥发性化感物质对蚕豆叶表皮保卫细胞的影响

    Institute of Scientific and Technical Information of China (English)

    周健; 马丹炜; 陈永甜; 袁立娜; 黄雪婷; 瞿欢欢

    2016-01-01

    30 min at 25℃ in illumination incubator. The results showed that volatile oil,α-terpinene and cymene resulted in the decrease of viabilities and increase of abnormal nuclei rates in guard cell of V. faba leaves. The cytotox-icity on guard cells decreased successively from volatile oil toα-terpinene to cymene. The apoptosis features including nuclear pyknotic, malposition, stretch and degradation were observed in guard cell under the treatments of volatile oil,α-terpinene and cymene. However, the guard cell survival rates increased when strips were exposed to volatile oil,α-terpinene and cymene combined with different concentrations of a caspase inhibitor Z-VAD-FMK. These results sugges-ted that the volatile allelochemicals from Chenopodium ambrosioides induced guard cell caspase-dependent apoptosis in Vicia faba leaves.

  2. Functional Characterization and Expression of Molluscan Detoxification Enzymes and Transporters Involved in Dietary Allelochemical Resistance

    Science.gov (United States)

    2008-06-01

    of the West Indian region (Gulf of Mexico, Antilles, Bahamas, Florida Keys, Bermuda , South America, Caribbean) represent 38% of the known fauna with...in red. Values at branch points represent MIL bootstrap values calculated with 100 replications. Triangles represent portions of the tree that were

  3. [Effects of allelochemical EMA from reed on the production and release of cyanotoxins in Microcystis aeruginosa].

    Science.gov (United States)

    Men, Yu-jie; Hu, Hong-ying

    2007-09-01

    The growth inhibition of ethyl-2-methylacetoacetate (EMA) isolated from common reed (Phragmites australis Trin. or Phragmites communis Trin.) on the growth of Microcystis aeruginosa PCC7806 was investigated and the intracellular and extracellular concentration of cyanotoxin (MC-LR) after treatment of EMA were tested. The experimental results indicated that EMA has significant inhibitory effect on the growth of M. aeruginosa PCC7806, and the value of EC(50,7d) was 2.0 mg x L(-1). However, the inhibition declined with the cultivation time. During the whole cultivation period, EMA showed no significant effect on the release of MC-LR from cells to the culture. After 7 days, the amount of intracellular MC-LR per cell unit increased with the increasing of EMA concentration. The amount of MC-LR per cell unit was 25 ng x (10(6) cells)(-1) after the treatment with 1.5 mg x L(-1) EMA, which was increased by 39% compared with the control. The total MC-LR production (including intracellular and extracellular MC-LR) first slightly increased and then decreased significantly with the increase of EMA concentration. After the treatment with 3 mg x L(-1) EMA, the total MC-LR production was 28 microg x L(-1) (only half of that in the control). After 16 days, EMA showed no significant effect on both the amount of MC-LR per cell and the total MC-LR production.

  4. Cytochrome P450s from the fall armyworm (Spodoptera frugiperda): responses to plant allelochemicals and pesticides.

    Science.gov (United States)

    Giraudo, M; Hilliou, F; Fricaux, T; Audant, P; Feyereisen, R; Le Goff, G

    2015-02-01

    Spodoptera frugiperda is a polyphagous lepidopteran pest that encounters a wide range of toxic plant metabolites in its diet. The ability of this insect to adapt to its chemical environment might be explained by the action of major detoxification enzymes such as cytochrome P450s (or CYP). Forty-two sequences coding for P450s were identified and most of the transcripts were found to be expressed in the midgut, Malpighian tubules and fat body of S. frugiperda larvae. Relatively few P450s were expressed in the established cell line Sf9. In order to gain information on how these genes respond to different chemical compounds, larvae and Sf9 cells were exposed to plant secondary metabolites (indole, indole-3-carbinol, quercetin, 2-tridecanone and xanthotoxin), insecticides (deltamethrin, fipronil, methoprene, methoxyfenozide) or model inducers (clofibrate and phenobarbital). Several genes were induced by plant chemicals such as P450s from the 6B, 321A and 9A subfamilies. Only a few genes responded to insecticides, belonging principally to the CYP9A family. There was little overlap between the response in vivo measured in the midgut and the response in vitro in Sf9 cells. In addition, regulatory elements were detected in the promoter region of these genes. In conclusion, several P450s were identified that could potentially be involved in the adaptation of S. frugiperda to its chemical environment.

  5. Phytotoxicity of cardoon (Cynara cardunculus) allelochemicals on standard target species and weeds.

    Science.gov (United States)

    Rial, Carlos; Novaes, Paula; Varela, Rosa M; Molinillo, José M G; Macias, Francisco A

    2014-07-16

    Cardoon (Cynara cardunculus L.) is a native plant to the Iberian Peninsula and the European Atlantic coast and invasive in American environments. Different solvents were used to perform cardoon extracts that were tested in phytotoxic bioassays. The ethyl acetate extract had the highest inhibitory activity so this was tested on the germination and growth of standard target species (lettuce, watercress, tomato, and onion) and weeds (barnyardgrass and brachiaria). The ethyl acetate extract was very active on root growth in both standard target species and weeds and it was therefore fractionated by chromatography. The spectroscopic data showed that the major compounds were sesquiterpene lactones. Aguerin B, grosheimin, and cynaropicrin were very active on etiolated wheat coleoptile, standard target species, and weed growth. The presence of these compounds explains the bioactivity of the ethyl acetate extract. The strong phytotoxicity of these compounds on important weeds shows the potential of these compounds as natural herbicide models.

  6. Identification of safranal as the main allelochemical from saffron (Crocus sativus).

    Science.gov (United States)

    Mardani, Hossein; Sekine, Takayuki; Azizi, Majid; Mishyna, Maryia; Fujii, Yoshiharu

    2015-05-01

    Dried parts of 75 medicinal plant species collected from different regions in Iran were assayed by the Dish Pack Method for volatile allelopathic activity, using Lactuca sativa (lettuce) as the test plant. The highest (60%) inhibition was observed for saffron (stigma of Crocus sativus), followed by Dracocephalum kotschyi, Solanum nigrum and Artemisia aucheri. Safranal was identified as the main chemical by Headspace Gas Chromatography-Mass Spectrometry (HS- GC-MS) analyses of saffron. Moreover, the EC50 of safranal was evaluated as 1.2 μg/L (ppb). This is the first report on allelopathic activity of safranal as a bioactive compound identified from saffron.

  7. Allelochemical Control of Non-Indigenous Invasive Plant Species Affecting Military Testing and Training Activities

    Science.gov (United States)

    2010-10-01

    Dalmation toadflax Scrophulariaceae I F Potentilla recta Sulphur cinquefoil Rosaceae I F Sisymbrium altissimum Tall tumblemustard Brassicaceae I F...105 9.09 tap Fabaceae Potentilla arguta tall cinquefoil weak high 8,112 9.09 tap Rosaceae total seeds per gram 22145 Stipa

  8. Isoschaftoside, a C-glycosylflavonoid from Desmodium uncinatum root exudate, is an allelochemical against the development of Striga.

    Science.gov (United States)

    Hooper, Antony M; Tsanuo, Muniru K; Chamberlain, Keith; Tittcomb, Kay; Scholes, Julie; Hassanali, Ahmed; Khan, Zeyaur R; Pickett, John A

    2010-06-01

    In East African small-holder farming of maize, the cattle forage legume, Desmodium uncinatum is used as an intercrop due to its allelopathic inhibition of parasitism by Striga hermonthica, an obligate parasitic weed that can devastate the maize crop. Bioassay-guided fractionation of the root extract of D. uncinatum revealed isoschaftoside to be the main compound in the most potent fraction inhibiting growth of germinated S. hermonthica radicles. Bioassays repeated with isoschaftoside isolated from a different plant source, Passiflora incarnata, proved it to be a biologically active component. Analysis of the root exudates produced by hydroponically grown D. uncinatum showed isoschaftoside to be present in the hydroponic media at biologically active concentrations of 10-100 nM.

  9. The role of multixenobiotic transporters in predatory marine molluscs as counter-defense mechanisms against dietary allelochemicals.

    Science.gov (United States)

    Whalen, Kristen E; Sotka, Erik E; Goldstone, Jared V; Hahn, Mark E

    2010-09-01

    Multixenobiotic transporters have been extensively studied for their ability to modulate the disposition and toxicity of pharmacological agents, yet their influence in regulating the levels of dietary toxins within marine consumers has only recently been explored. This study presents functional and molecular evidence for multixenobiotic transporter-mediated efflux activity and expression in the generalist gastropod Cyphoma gibbosum, and the specialist nudibranch Tritonia hamnerorum, obligate predators of chemically defended gorgonian corals. Immunochemical analysis revealed that proteins with homology to permeability glycoprotein (P-gp) were highly expressed in T. hamnerorum whole animal homogenates and localized to the apical tips of the gut epithelium, a location consistent with a role in protection against ingested prey toxins. In vivo dye assays with specific inhibitors of efflux transporters demonstrated the activity of P-gp and multidrug resistance-associated protein (MRP) families of ABC transporters in T. hamnerorum. In addition, we identified eight partial cDNA sequences encoding two ABCB and two ABCC proteins from each molluscan species. Digestive gland transcripts of C. gibbosum MRP-1, which have homology to vertebrate glutathione-conjugate transporters, were constitutively expressed regardless of gorgonian diet. This constitutive expression may reflect the ubiquitous presence of high affinity substrates for C. gibbosum glutathione transferases in gorgonian tissues likely necessitating export by MRPs. Our results suggest that differences in multixenobiotic transporter expression patterns and activity in molluscan predators may stem from the divergent foraging strategies of each consumer.

  10. Devil's-claw (Proboscidea louisianica), essential oil and its components : Potential allelochemical agents on cotton and wheat.

    Science.gov (United States)

    Riffle, M S; Waller, G R; Murray, D S; Sgaramello, R P

    1990-06-01

    The potential allelopathic activity of devil's-claw [Proboscidea louisianica (Mill.) Thellung] essential oil and a few of the compounds it contains on the elongation of cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) radicles was studied using a Petri dish bioassay. Essential oil was collected by steam distillation using an all-glass-Teflon assembly. Ether extracts of the steam distillates from fresh devil's-claw were inhibitory to cotton and wheat radicle elongation. The following six components of devil's-claw essential oil identified by CGC-MS-DS were inhibitory to cotton and/or wheat at a concentration of 1 mM: vanillin, piperitenone, δ-cadinene,p-cymen-9-ol, α-bisabolol, and phenethyl alcohol.

  11. Research Progress on Weed-controlling by Using Allelochemicals%利用化感物质防除杂草研究进展

    Institute of Scientific and Technical Information of China (English)

    赵强; 董晓宁; 井伟龙; 赵海福

    2012-01-01

    该文阐述了化感作用的作用机理,国内外植物化感抑草的研究现状,进而指出了植物化感作用在抑制杂草方面的优越性及存在的问题,同时对其未来的发展进行了展望.%By elaborating the mechanism of action of allelopathy and the research status of weed-controlling of allelopathy at home and abroad,further pointing out superiority and existing problems of allelopathy in the management of weeds,at the same time looking into the future.

  12. Evidence for inhibition of bacterial luminescence by allelochemicals from Fibrocapsa japonica (Raphidophyceae), and the role of light and microalgal growth rate

    NARCIS (Netherlands)

    van Rijssel, Marion; de Boer, M. Karin; Tyl, Monika R.; Gieskes, Winfried W. C.

    2008-01-01

    The marine microalga Fibrocapsa japonica Toriumi and Takano (Raphidophyceae) produces haemolysins, neurotoxins and reactive oxygen species (ROS). To quantify potential effects of such bioactive compounds on surrounding organisms the marine bacterium Vibrio fischeri was exposed to F. japonica culture

  13. 东北山樱桃叶绿素荧光对外源化感物质的响应%Response of Cerasus sachalinensis chlorophyll fluorescence to exogenous allelochemical

    Institute of Scientific and Technical Information of China (English)

    高鹤

    2016-01-01

    以东北山樱桃实生幼苗为试材,利用Hansatch PEA,采用叶绿素荧光诱导动力学理论和JIP-test数据分析方法,研究对羟基苯甲酸对叶片叶绿素荧光参数的影响。结果表明:幼苗在不同浓度对羟基苯甲酸(0.1、1、10 mmol·L-1)处理下的叶片光合性能指数、捕获的激子将电子传递到电子传递链中QA-下游的其他电子受体的概率、用于电子传递的量子产额和单位面积有活性的反应中心数目较对照均有所下降;PSⅡ最大量子效率、单位面积有活性的反应中心数目几乎没有变化;而PSⅡ受体侧的电子受体库容量则高于对照,且呈“上升—下降”趋势。天线色素吸收的能量在低浓度下有小幅升高,反应中心捕获的能量、用于电子传递的能量及用于热耗散的能量则无明显变化。可见,对羟基苯甲酸对东北山樱桃叶片光合结构的不同部位产生影响,进而降低光合性能,影响光合作用。%The effects of para-hydroxybenzoic on chlorophyll fluorescence parameters in seedlings of Cerasus sachalinensis were stud-ied through Plant Efficiency Analyzer Hansatch PEA.The results showed that with different concentrations(0.1,1,10 mmol·L-1)of para-hydroxybenzoic acid treatments,Photosynthetic characteristics in leaf,Probability of transferring electrons to other electron ac-ceptors in downstream of QA through electron transport chain,quantum yield for electron transport and density of RC(RC/CSm)were all decreased in comparison to control.The maximum quantum efficiency of PSII(φpo),density of RC(RC/CS0)hardly varied, whereas that normalised total complementary area above the O-J-I-P transie(Sm)increased.In addition,absorption flux per CS(ABS/RC)increased,trapped energy flux per CS(TRo/RC),election transport flux per RC(ETo/RC)and dissipated energy flux per RC (DIo/RC)hardly varied.These results demonstrate that para-hydroxybenzoic acid effect photosynthesis by affecting different positions in photosynthesis of Cerasus sachalinensis and decrease the performance of photosynthesis.

  14. Differential morphological, cytological and biochemical responses of two rice cultivars to coumarin

    Science.gov (United States)

    Plants are often exposed to allelochemicals in the environment produced by neighboring plants. Coumarin is a common allelochemical produced by many higher plants. Two cultivars (susceptible BS-2000 and less susceptible BR-41) of rice (Oryza sativa L.) were selected to compare their differential root...

  15. Is (-)-Catechin a "Novel Weapon" of Spotted Knapweed (Centaurea stoebe)?

    Science.gov (United States)

    The “novel weapons” hypothesis states that some invasive weed species owe part of their success as invaders to allelopathy mediated by allelochemicals that are new to the native species. Presumably, no resistance has evolved among the native species to this new allelochemical (i.e. the novel weapon...

  16. [Advances in research on allelopathy of ginseng and American ginseng].

    Science.gov (United States)

    Lei, Fengjie; Zhang, Aihua; Zhang, Qiuju; Zhang, Lianxue

    2010-09-01

    Both ginseng and American ginseng can not be replanted on the same soil consecutively. The article reviews the development and progress of studies on the replant failure of ginseng and American ginseng with a special focus on allelopathy in recent years. The allelopathy effect in ginseng and American ginseng is reviewed from following aspects: collecting and extracting allelochemicals, effects of such allelochemicals on seeds germination, seedlings growth, antioxidant enzyme activities in ginseng roots, growth of ginseng pathogens and ginseng callus, and more. It is presumed that inhibitory allelopathy is one of the many possible factors contributing to the replant failure of ginseng and American ginseng. Based on that, the paper points out problems in current researches on the allelopathic effect of ginseng and American ginseng: the allelochemicals are consist of a mixture, which one plays the specific role is not clear; concentrating on a single allelochemical while ignoring the interaction among allelochemicals. It is suggested that further study for this area should be focused on the interactions among allelochemicals and interactions between allelochemicals and environmental impact factors. Another area of needed research is that of the migration and transformation of allelochemicals in soil and microbial involvement in allelopathy on the growth of ginseng and American ginseng.

  17. 芦苇化感物质EMA对铜绿微囊藻生长及藻毒素产生和释放的影响%Effects of Allelochemical EMA from Reed on the Production and Release of Cyanotoxins in Microcystis aeruginosa

    Institute of Scientific and Technical Information of China (English)

    门玉洁; 胡洪营

    2007-01-01

    研究了芦苇化感物质2-甲基乙酰乙酸乙酯(ethyl-2-methylacetoacetate,EMA)对铜绿微囊藻PCC7806的生长抑制特性以及对微囊藻毒素MC-LR产生和释放的影响.结果表明,EMA在培养1周内对铜绿微囊藻PCC7806具有较强的抑制作用,EC50,7d值为2.0 mg·L-1,但EMA的抑制效果随时间的延长而减弱.整个培养期间,EMA对MC-LR的胞外释放无显著影响.培养7 d后,单位藻细胞内MC-LR的含量随EMA浓度的增加而升高,EMA投加浓度为1.5 mg·L-1时,单位藻细胞MC-LR的含量为25ng·(106个)-1,比对照组增加了39%.但单位体积培养液中MC-LR总量(胞内和胞外的总和)随EMA浓度增加先略微升高后显著降低,EMA投加浓度为3 mg·L-1时,培养液中MC-LR胞内胞外总量为28 μg·L-1,约为对照组的一半;16 d后,EMA对单个细胞内MC-LR的含量以及MC-LR总量均无显著影响.

  18. Efeito de aleloquímicos em tricomas foliares de tomateiro na repelência a ácaro (Tetranychus urticae Koch. em genótipos com teores contrastantes de 2-tridecanona Effect of allelochemicals in tomato leaf trichomes on mite (Tetranychus urticae Koch. repellency in genotypes with different levels of 2-tridecanone

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Aragão

    2002-01-01

    Full Text Available Com o objetivo de avaliar a ação de repelência a ácaro Tetranychus urticae Koch. em folíolos de tomateiro com altos teores do aleloquímico 2-tridecanona (2-TD associado a tricomas glandulares, utilizaram-se linhagens avançadas 'TOM 600' e 'TOM 601' (altos teores de 2-TD 'TOM 584' (padrão com baixo teor de 2-TD e seus parentais 'PI 134417' Lycopersicon hirsutum Dunal var. glabratum Mill. (alto teor de 2-TD e 'TOM 556' Lycopersicon esculentum Mill. (baixo teor de 2-TD. O experimento foi realizado em câmara com temperatura de 16 ºC e 68% de umidade. A metodologia usada consistiu em se colocar um folíolo de cada genótipo sobre uma folha de papel tipo ofício, a qual foi fixada sobre uma folha de isopor. O folíolo foi fixado com uma tachinha metálica no centro do mesmo, sendo então colocados 10 ácaros fêmeas sobre a tachinha para que fossem medidas as distâncias percorridas pelos artrópodes em tempos diferenciados. De maneira geral, a distância percorrida pelos ácaros aumentou de acordo com maiores tempos de ensaio. Obteve-se em 'PI 134417', juntamente com 'TOM 600' e 'TOM 601', menores médias de distâncias percorridas pelos ácaros nos tempos avaliados em comparação ao 'TOM 556' e 'TOM 584' em razão da repelência exercida que se associa a maiores teores de 2-tridecanona.For the evaluation of the mites (Tetranychus urticae Koch. repellency in tomato leaflets with high levels of 2-tridecanone (2-TD associated to glandular trichomes, we used the advanced lines, 'TOM 600' and 'TOM 601' (high 2-TD levels 'TOM 584' (control, low 2-TD levels and the parents 'PI 134417' Lycopersicon hirsutum Dunal var. glabratum (high 2-TD levels and 'TOM 556' Lycopersicon esculentum Mill. (low 2-TD levels. The experiment was carried out at 16ºC and 68% relative moisture. Leaflets of each genotype were placed on a sheet of paper, set on a Styrofoam sheet. Ten female mites were placed on a metallic thumbtack at the center of the leaflets, and the distances the mites moved after 20, 40 and 60 minutes were measured. In general, the distance the mites moved increased according to the time they were left on the thumbtack. The access 'PI 134417', along with the lines 'TOM 600' and 'TOM 601', showed lower distance averages then 'TOM 556' and 'TOM 584'. Those genotypes showed higher repellency, whitch is associated with higher levels of 2-TD.

  19. Effects of endophyte infection on reactive oxygen content and protective enzyme activity in branchlet of Casuarina equisetifolia seedling under stress of two allelochemicals%2种化感物质胁迫下内生真菌感染对木麻黄幼苗小枝活性氧代谢和清除系统的影响

    Institute of Scientific and Technical Information of China (English)

    龙凤; 洪滔; 林勇明; 谢安强; 吴承祯; 洪伟; 李键

    2016-01-01

    为探讨使用木麻黄-内生真菌共生体应对连栽障碍的可能性,在前期已获得2种木麻黄化感物质(槲皮黄素-3-α-阿拉伯糖苷,Q3A;槲皮黄素-3-β-葡萄糖苷,Q3B)胁迫对木麻黄(Endophyte-free,EF)幼苗小枝活性氧代谢和清除系统影响的基础上,本研究以感染(Endophyte-infected,EI)内生真菌Aspergillus sp.的木麻黄水培幼苗(Casuarina equisetifolia Forst.)为实验材料,在控制环境水培条件下,分析内生真菌对Q3A和Q3B胁迫下木麻黄幼苗小枝活性氧代谢和清除系统的影响.结果显示,内生真菌的侵染能够有限缓解木麻黄化感物质的胁迫,在中度轻度及短期胁迫(100 mg/L 0-12 h、50 mg/L 0-24 h、25 mg/L 0-36 h、12.5 mg/L 0-48 h)下有明显的效果,表现在与木麻黄EF相比,木麻黄EI活性氧含量显著下降,丙二醛(MDA)含量显著降低,保护酶活性显著增加;内生真菌缓解化感物质胁迫的有效浓度和胁迫期与木麻黄EF能够耐受的化感物质胁迫浓度和胁迫期一致;Q3A胁迫下木麻黄EI保护酶活性显著高于Q3B胁迫下的提升幅度.说明内生真菌提升了宿主木麻黄的抗逆性,对宿主应对Q3A胁迫的贡献更大,推测内生真菌对木麻黄EI保护酶系统的提升需要建立在木麻黄保护酶系统合成和降解还未受到不可逆伤害的前提下.

  20. The role of momilactones in rice allelopathy.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Peters, Reuben J

    2013-02-01

    Large field screening programs and laboratory experiments in many countries have indicated that rice is allelopathic and releases allelochemical(s) into its environment. A number of compounds, such as phenolic acids, fatty acids, phenylalkanoic acids, hydroxamic acids, terpenes, and indoles, have been identified as potential rice allelochemicals. However, the studies reviewed here demonstrate that the labdane-related diterpenoid momilactones are the most important, with momilactone B playing a particularly critical role. Rice plants secrete momilactone B from their roots into the neighboring environments over their entire life cycle at phytotoxic levels, and momilactone B seems to account for the majority of the observed rice allelopathy. In addition, genetic studies have shown that selective removal of the momilactones only from the complex mixture found in rice root exudates significantly reduces allelopathy, demonstrating that these serve as allelochemicals, the importance of which is reflected in the presence of a dedicated momilactone biosynthetic gene cluster in the rice genome.

  1. Long-term allelopathic control of phytoplankton by the submerged macrophyte Elodea nuttallii

    NARCIS (Netherlands)

    Vanderstukken, M.; Declerck, S.A.J.; Decaestecker, E.; Muylaert, K.

    2014-01-01

    Keywords: allelochemicals; chemical ecology; competition; nutrient limitation; shallow lakes Summary 1.It is well known that submerged macrophytes can suppress phytoplankton blooms in lakes and thus promote water quality and biodiversity. One of the possible mechanisms through which submerged macrop

  2. Weed-Suppressing Effect and Mechanism of Allelopathic Rice Accessions

    Institute of Scientific and Technical Information of China (English)

    HU Fei; KONG Chui-hua; XU Xiao-hua; ZHANG Chao-xian; CHEN Xiong-hui

    2004-01-01

    Two allelopathic rice accessions, PI312777 and Allelopathyl, significantly suppressedthe growth of associated weeds in the field. Moreover, their weed-suppressing effectswere correlated with the cultivation patterns. The weed-suppressing effects of throwingand transplanting were more effective than that of direct seeding. Furthermore, theamounts of allelochemicals (resorcinols, flavones and hydroxamic acids) produced andreleased from two allelopathic rice accessions were much higher than that from a non-allelopathic rice variety Hua-Jing-Xian 1, and reached the maximum concentration at the6th leaf stage. Differences in the weed-suppressing effects of rice accessions appear toresult from the accessions producing and releasing different amounts of allelochemicalsin the field. Further research confirmed that in PI312777 plants, allelochemicals weresynthesized by the above-ground parts, and then secreted through the root tissues. Roottissues of PI312777 plants never produced the allelochemicals. Root exudates fromPI312777 could significantly inhibit the growth of E. crus-galli surrounding rice plantsin water culture. However, when activated carbon was added to the culture solution, whichcould absorb allelochemicals from root exudates, the growth of E. crus-galli was nolonger significantly inhibited. Weed-suppressing effects of rice accessions depended onallelopathy, cultivation patterns and other factors in rice fields, while allelopathywas one of important factors. Interestingly, the amounts of allelochemicals produced andreleased from allelopathic rice plants may be induced by the presence of E. crus-galli.This suggests that there is a possible chemical recognition between rice and E. crus-galli.

  3. Root secretion stimulating ash growth in larch-ash mixed forest

    Institute of Scientific and Technical Information of China (English)

    吴俊民; 刘广平; 王晓水; 吴保国

    2000-01-01

    Allelopathic effect of larch (Larix gmelini ) on the ash growth (Fraximus mandshurica) was studied in artificial cultivation tests. The results revealed that the larch root secretion obviously stimulated the ash growth. In order to determine the main stimulation allelochemicals, the chemical composition was analyzed. By contrasting the contents of carbohydrate and aminoacid in root secretion of larch and ash, it was concluded that the carbohydrate and aminoacid were not important stimulation allelochemicals. The organic acid and other components in root secretion of larch and ash were analyzed by GC and GC-MS analysis. The sand culture tests were carried out with selected model compounds. The results showed that benzeneacetic acid, benzenepropionic acid and phenolic acids in root secretion of larch were the main stimulation allelochemicals.

  4. Weed-Suppressing Effect and Mechanism of Allelopathic Rice Accessions

    Institute of Scientific and Technical Information of China (English)

    HUFei; KONGChui-hua; XUXiao-hua; ZHANGChao-xian; CHENXiong-hui

    2004-01-01

    Two allelopathic rice accessions, PI312777 and Allelopathy i, significantly suppressed the growth of associated weeds in the field. Moreover, their weed-suppressing effects were correlated with the cultivation patterns. The weed-suppressing effects of throwing and transplanting were more effective than that of direct seeding. Furthermore, the amounts of allelochemicals (resorcinols, flavones and hydroxamic acids) produced and released from two allelopathic rice accessions were much higher than that from a nonallelopathic rice variety Hua-Jing-Xian i, and reached the maximum concentration at the 6th leaf stage. Differences in the weed-suppressing effects of rice accessions appear to result from the accessions producing and releasing different amounts of allelochemicals in the field. Further research confirmed that in PI312777 plants, allelochemicals were synthesized by the above-ground parts, and then secreted through the root tissues. Root tissues of PI312777 plants never produced the allelochemicals. Root exudates from PI312777 could significantly inhibit the growth of E. crus-galli surrounding rice plants in water culture. However, when activated carbon was added to the culture solution, which could absorb allelochemicals from root exudates, the growth of E. crus-galli was no longer significantly inhibited. Weed-suppressing effects of rice accessions depended on allelopathy, cultivation patterns and other factors in rice fields, while allelopathy was one of important factors. Interestingly, the amounts of allelochemicals produced and released from allelopathic rice plants may be induced by the presence of E. crus-galli.This suggests that there is a possible chemical recognition between rice and E. crus-galli.

  5. Allelopathy in crop/weed interactions--an update.

    Science.gov (United States)

    Belz, Regina G

    2007-04-01

    Since varietal differences in allelopathy of crops against weeds were discovered in the 1970s, much research has documented the potential that allelopathic crops offer for integrated weed management with substantially reduced herbicide rates. Research groups worldwide have identified several crop species possessing potent allelopathic interference mediated by root exudation of allelochemicals. Rice, wheat, barley and sorghum have attracted most attention. Past research focused on germplasm screening for elite allelopathic cultivars and the identification of the allelochemicals involved. Based on this, traditional breeding efforts were initiated in rice and wheat to breed agronomically acceptable, weed-suppressive cultivars with improved allelopathic interference. Promising suppressive crosses are under investigation. Molecular approaches have elucidated the genetics of allelopathy by QTL mapping which associated the trait in rice and wheat with several chromosomes and suggested the involvement of several allelochemicals. Potentially important compounds that are constitutively secreted from roots have been identified in all crop species under investigation. Biosynthesis and exudation of these metabolites follow a distinct temporal pattern and can be induced by biotic and abiotic factors. The current state of knowledge suggests that allelopathy involves fluctuating mixtures of allelochemicals and their metabolites as regulated by genotype and developmental stage of the producing plant, environment, cultivation and signalling effects, as well as the chemical or microbial turnover of compounds in the rhizosphere. Functional genomics is being applied to identify genes involved in biosynthesis of several identified allelochemicals, providing the potential to improve allelopathy by molecular breeding. The dynamics of crop allelopathy, inducible processes and plant signalling is gaining growing attention; however, future research should also consider allelochemical release

  6. Effects of cotton condensed tannin, maysin (Corn) and pinitol (soybeans) onHeliothis zea growth and development.

    Science.gov (United States)

    Reese, J C; Chan, B G; Waiss, A C

    1982-12-01

    Maysin, a flavone glycoside from corn silks, inhibits ingestion, and thus growth, ofHeliothis zea (Boddie) larvae. Pinitol from soybeans inhibitedH. zea growth by the same mechanism. Despite the widely held assumption that tannins inhibit growth by inhibiting assimilation, cotton condensed tannin inhibitedH. zea growth by reducing ingestion; no evidence was found for a reduction in assimilation. Neonate larvae are shown to be much more sensitive to allelochemics than larvae that have fed on control diet before being transferred to diet containing plant allelochemics.

  7. Mechanical wounding under field conditions: A potential tool to increase the allelopathic inhibitory effect of cover crops on weeds?

    NARCIS (Netherlands)

    Kruidhof, H.M.; Dam, van N.M.; Ritz, C.; Lotz, L.A.P.; Kropff, M.J.; Bastiaans, L.

    2014-01-01

    To increase the inhibitory effect of soil-incorporated cover crop residues on germination and early growth of weeds, the allelochemical content of the cover crop at the time of soil incorporation should be maximal. We investigated whether mechanical damaging in spring induced the production of allel

  8. Hairy vetch (Vicia villosa) seed size affects germination response to coumarin

    Science.gov (United States)

    The inhibition of seed germination by an allelochemical is generally greater in small seeds than in large seeds. This response may have significant impact on weed control by allelopathic cover crops where the small-seeded weeds would be more effectively controlled than large-seeded species. The stu...

  9. Radish (Raphanus sativus) seed size affects germination response to coumarin

    Science.gov (United States)

    The inhibition of seed germination by an allelochemical is generally greater in small seeds than in large seeds. Studies reporting these results used a large number of plant species that varied in seed size, which might have introduced differences in germination characteristics or various parameter...

  10. Effects of benzoic acid and cadmium toxicity on wheat seedlings

    Directory of Open Access Journals (Sweden)

    Kavita Yadav

    2013-06-01

    Full Text Available Benzoic acid (BA and Cd exhibit cumulative effects on plants due to their accumulation in the soil. The present study reports the effects of BA an allelochemical, Cd and their combinations on seed germination, seedling growth, biochemical parameters, and response of antioxidant enzymes in Triticum aestivum L. The experiment was conducted in sand supplemented with Hoagland nutrient solution. Benzoic acid was applied at concentrations of 0.5, 1.0, and 1.5 mM with or without Cd (7 mg L-1 to observe effects of allelochemical and Cd alone and in combination on wheat. Both stresses exhibited inhibitory effect on growth and metabolism of wheat seedlings. The allelochemical in single and combined treatments with Cd decreased seedling growth as compared to Cd stress. The two stresses significantly enhanced malondialdehyde content of wheat seedlings. The activity of other antioxidant enzymes, viz. superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase (APX, and guaiacol peroxidase (POX were also recorded. SOD increased in seedlings under the two stresses. CAT more prominently ameliorates the toxic effects of H2O2 as compared with APX and POX and protected wheat seedlings from oxidative stress. Allelochemical buttressed the toxic effect of Cd on wheat seedlings.

  11. [Allelopathic effects of cultured Cucurbita moschata root exudates].

    Science.gov (United States)

    Li, Min; Ma, Yongqin; Shui, Junfeng

    2005-04-01

    By using the techniques of tissue culture, bio-assay and laboratory analysis, this paper studied the effects of the allelopathic chemicals from pumpkin (Cucurbita moschata) roots on the seed germination and seedling growth of pumpkin, wheat (Triticum aestivum), and radish (Raphanus sativus). The pumpkin root was cultured on a sterile B5 media, and the concentrations of macro- and microelements, organic supplements and hormones in the media were adjusted by using an orthogonal design. After culturing, the culture media was filtered and used in a bioassay to test the autotoxicity and allelopathic effects. The results showed that the pumpkin had both autotoxic and allelopathic effects, and the media having been used to culture the pumpkin roots contained the chemicals that significantly inhibited the seedling growth of wheat and radish. The allelopathic effect decreased when the culture media was diluted. The production of allelochemicals seemed to be related to the growth rate of the pumpkin roots. When the root growth was rapid, the concentration of allelochemicals was high. The allelopathic effect was stronger on radish than on wheat. The optimum concentrations of macro- and microelements, vitamins and hormones for culturing pumpkin root were determined, and the effect of pumpkin root nutrition on the production of allelochemicals was tested. The results indicated that pumpkin root nutrition had a significant effect on the production of allelochemicals.

  12. Weeds Cause Losses in Field Crops through Allelopathy

    Directory of Open Access Journals (Sweden)

    Tasawer ABBAS

    2016-03-01

    Full Text Available A large number of weeds are known to be associated with crops and causing economic losses. Weeds interfere with crops through competition and allelopathy. They produce secondary metabolites known as allelochemicals, which belong to numerous chemical classes such as phenolics, alkaloids, fatty acids, indoles, terpens etc. However, phenolics are the predominant class of allelochemicals. The allelochemicals release from weed plants takes place through leaf leachates, decomposition of plant residues, volatilization and root exudates. Weeds leave huge quantities of their residues in field and affect the associated, as well as succeeding crops, in various cropping systems. Liberation of allelochemicals from weeds affects the germination, stand establishment, growth, yield and physiology of crop plants. They cause substantial reduction in germination and growth of the crop plants by altering various physiological processes such as enzyme activity, protein synthesis, photosynthesis, respiration, cell division and enlargement, which ultimately leads to a significant reduction in crop yield. In crux, allelopathic weeds represent a potential threat for crop plants and cause economic losses.

  13. Algal-bloom control by allelopathy of aquatic macrophytes——A review

    Institute of Scientific and Technical Information of China (English)

    Hongying HU; Yu HONG

    2008-01-01

    Algal-bloom control is an important issue for water environment protection as it induces several nega-tive impacts on the lives of aquatic organisms, aquacul-ture, landscaping, and human health. The development of an environment-friendly, cost-effective, and convenient alternative for controlling algal bloom has gained much concern. Using the allelopathy of aquatic macrophytes as a novel and safe method for algal-bloom control is a promising alternative. This paper reviews the develop-ment and potential application about allelopathy of aquatic plants on algae, including the allelopathic research history, the potential research problems, the research methodology, and the reported aquatic macro-phytes and their inhibitory allelochemicals. Potential modes of inhibition action of allelochemicals on algae, possible ways for application, and future development directions of research on algal-bloom control by aquatic macrophytes were also presented.

  14. Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors.

    Science.gov (United States)

    Venturelli, Sascha; Belz, Regina G; Kämper, Andreas; Berger, Alexander; von Horn, Kyra; Wegner, André; Böcker, Alexander; Zabulon, Gérald; Langenecker, Tobias; Kohlbacher, Oliver; Barneche, Fredy; Weigel, Detlef; Lauer, Ulrich M; Bitzer, Michael; Becker, Claude

    2015-11-01

    To secure their access to water, light, and nutrients, many plant species have developed allelopathic strategies to suppress competitors. To this end, they release into the rhizosphere phytotoxic substances that inhibit the germination and growth of neighbors. Despite the importance of allelopathy in shaping natural plant communities and for agricultural production, the underlying molecular mechanisms are largely unknown. Here, we report that allelochemicals derived from the common class of cyclic hydroxamic acid root exudates directly affect the chromatin-modifying machinery in Arabidopsis thaliana. These allelochemicals inhibit histone deacetylases both in vitro and in vivo and exert their activity through locus-specific alterations of histone acetylation and associated gene expression. Our multilevel analysis collectively shows how plant-plant interactions interfere with a fundamental cellular process, histone acetylation, by targeting an evolutionarily highly conserved class of enzymes.

  15. AtMRP1 gene of Arabidopsis encodes a glutathione S-conjugate pump: Isolation and functional definition of a plant ATP-binding cassette transporter gene

    OpenAIRE

    Lu, Yu-Ping; Li, Ze-Sheng; Rea, Philip A.

    1997-01-01

    Because plants produce cytotoxic compounds to which they, themselves, are susceptible and are exposed to exogenous toxins (microbial products, allelochemicals, and agrochemicals), cell survival is contingent on mechanisms for detoxifying these agents. One detoxification mechanism is the glutathione S-transferase-catalyzed glutathionation of the toxin, or an activated derivative, and transport of the conjugate out of the cytosol. We show here that a transporter responsible for the removal of g...

  16. Enhanced lignin monomer production caused by cinnamic Acid and its hydroxylated derivatives inhibits soybean root growth.

    Directory of Open Access Journals (Sweden)

    Rogério Barbosa Lima

    Full Text Available Cinnamic acid and its hydroxylated derivatives (p-coumaric, caffeic, ferulic and sinapic acids are known allelochemicals that affect the seed germination and root growth of many plant species. Recent studies have indicated that the reduction of root growth by these allelochemicals is associated with premature cell wall lignification. We hypothesized that an influx of these compounds into the phenylpropanoid pathway increases the lignin monomer content and reduces the root growth. To confirm this hypothesis, we evaluated the effects of cinnamic, p-coumaric, caffeic, ferulic and sinapic acids on soybean root growth, lignin and the composition of p-hydroxyphenyl (H, guaiacyl (G and syringyl (S monomers. To this end, three-day-old seedlings were cultivated in nutrient solution with or without allelochemical (or selective enzymatic inhibitors of the phenylpropanoid pathway in a growth chamber for 24 h. In general, the results showed that 1 cinnamic, p-coumaric, caffeic and ferulic acids reduced root growth and increased lignin content; 2 cinnamic and p-coumaric acids increased p-hydroxyphenyl (H monomer content, whereas p-coumaric, caffeic and ferulic acids increased guaiacyl (G content, and sinapic acid increased sinapyl (S content; 3 when applied in conjunction with piperonylic acid (PIP, an inhibitor of the cinnamate 4-hydroxylase, C4H, cinnamic acid reduced H, G and S contents; and 4 when applied in conjunction with 3,4-(methylenedioxycinnamic acid (MDCA, an inhibitor of the 4-coumarate:CoA ligase, 4CL, p-coumaric acid reduced H, G and S contents, whereas caffeic, ferulic and sinapic acids reduced G and S contents. These results confirm our hypothesis that exogenously applied allelochemicals are channeled into the phenylpropanoid pathway causing excessive production of lignin and its main monomers. By consequence, an enhanced stiffening of the cell wall restricts soybean root growth.

  17. Phytotoxic effects of (+/--catechin in vitro, in soil, and in the field.

    Directory of Open Access Journals (Sweden)

    Inderjit

    Full Text Available BACKGROUND: Exploring the residence time of allelochemicals released by plants into different soils, episodic exposure of plants to allelochemicals, and the effects of allelochemicals in the field has the potential to improve our understanding of interactions among plants. METHODOLOGY/PRINCIPAL FINDINGS: We conducted experiments in India and the USA to understand the dynamics of soil concentrations and phytotoxicity of (+/--catechin, an allelopathic compound exuded from the roots of Centaurea maculosa, to other plants in vitro and in soil. Experiments with single and pulsed applications into soil were conducted in the field. Experimental application of (+/--catechin to soils always resulted in concentrations that were far lower than the amounts added but within the range of reported natural soil concentrations. Pulses replenished (+/--catechin levels in soils, but consistently at concentrations much lower than were applied, and even pulsed concentrations declined rapidly. Different natural soils varied substantially in the retention of (+/--catechin after application but consistent rapid decreases in concentrations over time suggested that applied experimental concentrations may overestimate concentrations necessary for phytotoxicity by over an order of magnitude. (+/--Catechin was not phytotoxic to Bambusa arundinacea in natural Indian soil in a single pulse, but soil concentrations at the time of planting seeds were either undetectable or very low. However, a single dose of (+/--catechin suppressed the growth of bamboo in sand, in soil mixed with organic matter, and Koeleria macrantha in soils from Montana and Romania, and in field applications at 40 microg l(-1. Multiple pulses of (+/--catechin were inhibitory at very low concentrations in Indian soil. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that (+/--catechin is highly dynamic in natural soils, but is phytotoxic well below natural concentrations measured in some soils and applied

  18. Biochemical Mechanisms for Geographical Adaptations to Novel Toxin Exposures in Butterflyfish.

    Directory of Open Access Journals (Sweden)

    Aileen Maldonado

    Full Text Available Some species of butterflyfish have had preyed upon corals for millions of years, yet the mechanism of butterflyfish specialized coral feeding strategy remains poorly understood. Certain butterflyfish have the ability to feed on allelochemically rich soft corals, e.g. Sinularia maxima. Cytochrome P450 (CYP is the predominant enzyme system responsible for the detoxification of dietary allelochemicals. CYP2-like and CYP3A-like content have been associated with butterflyfish that preferentially consumes allelochemically rich soft corals. To investigate the role of butterflyfish CYP2 and CYP3A enzymes in dietary preference, we conducted oral feeding experiments using homogenates of S. maxima and a toxin isolated from the coral in four species of butterflyfish with different feeding strategies. After oral exposure to the S. maxima toxin 5-episinulaptolide (5ESL, which is not normally encountered in the Hawaiian butterflyfish diet, an endemic specialist, Chaetodon multicinctus experienced 100% mortality compared to a generalist, Chaetodon auriga, which had significantly more (3-6 fold higher CYP3A-like basal content and catalytic activity. The specialist, Chaetodon unimaculatus, which preferentially feed on S. maxima in Guam, but not in Hawaii, had 100% survival, a significant induction of 8-12 fold CYP3A-like content, and an increased ability (2-fold to metabolize 5ESL over other species. Computer modeling data of CYP3A4 with 5ESL were consistent with microsomal transformation of 5ESL to a C15-16 epoxide from livers of C. unimaculatus. Epoxide formation correlated with CYP3A-like content, catalytic activity, induction, and NADPH-dependent metabolism of 5ESL. These results suggest a potentially important role for the CYP3A family in butterflyfish-coral diet selection through allelochemical detoxification.

  19. Assessment of Allelopathic Potential of Melastoma malabathricum L. on Radish raphanus sativus L. and Barnyard Grass (Echinochloacrus-galli)

    OpenAIRE

    M. FARAVANI; H. B. BAKI; A. KHALIJ

    2008-01-01

    Melastoma malabathricum L. is a weedy invasive shrub in arable lands, abandoned farmlands, secondary forest openings and derelict areas in Malaysia. Some allelochemicals present in this plant extracts may, directly, prevent or promote germination when environmental conditions are conducive to growth and establishment. It may have an important role, indirectly, in determining plant community structures. The aqueous extract and methanol extracts , were assayed for the aqueous extract of fresh m...

  20. Research progress on the use of plant allelopathy in agriculture and the physiological and ecological mechanisms of allelopathy

    Directory of Open Access Journals (Sweden)

    Fang eCheng

    2015-11-01

    Full Text Available Allelopathy is a common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms. These biochemicals are known as allelochemicals and have beneficial or detrimental effects on target organisms. Plant allelopathy is one of the modes of interaction between receptor and donor plants and may exert either positive effects (e.g., for agricultural management, such as weed control, crop protection, or crop re-establishment or negative effects (e.g., autotoxicity, soil sickness, or biological invasion. To ensure sustainable agricultural development, it is important to exploit cultivation systems that take advantage of the stimulatory / inhibitory influence of allelopathic plants to regulate plant growth and development and to avoid allelopathic autotoxicity. Allelochemicals can potentially be used as growth regulators, herbicides, insecticides and antimicrobial crop protection products. Here, we reviewed the plant allelopathy management practices applied in agriculture and the underlying allelopathic mechanisms described in the literature. The major points addressed are as follows: (1 Description of management practices related to allelopathy and allelochemicals in agriculture. (2 Discussion of the progress regarding the mode of action of allelochemicals and the physiological mechanisms of allelopathy, consisting of the influence on cell micro- and ultra-structure, cell division and elongation, membrane permeability, oxidative and antioxidant systems, growth regulation systems, respiration, enzyme synthesis and metabolism, photosynthesis, mineral ion uptake, protein and nucleic acid synthesis. (3 Evaluation of the effect of ecological mechanisms exerted by allelopathy on microorganisms and the ecological environment. (4 Discussion of existing problems and proposal for future research directions in this field to provide a useful reference for future studies on

  1. A stable-isotope mass spectrometry-based metabolic footprinting approach to analyze exudates from phytoplankton

    DEFF Research Database (Denmark)

    Weber, Ralf J. M.; Selander, Erik; Sommer, Ulf;

    2013-01-01

    Phytoplankton exudates play an important role in pelagic ecology and biogeochemical cycles of elements. Exuded compounds fuel the microbial food web and often encompass bioactive secondary metabolites like sex pheromones, allelochemicals, antibiotics, or feeding attractants that mediate biological...... interactions. Despite this importance, little is known about the bioactive compounds present in phytoplankton exudates. We report a stable-isotope metabolic footprinting method to characterise exudates from aquatic autotrophs. Exudates from 13C-enriched alga were concentrated by solid phase extraction...

  2. Research Progress on the use of Plant Allelopathy in Agriculture and the Physiological and Ecological Mechanisms of Allelopathy

    OpenAIRE

    Fang eCheng; Zhihui eCheng

    2015-01-01

    Allelopathy is a common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms. These biochemicals are known as allelochemicals and have beneficial or detrimental effects on target organisms. Plant allelopathy is one of the modes of interaction between receptor and donor plants and may exert either positive effects (e.g., for agricultural management, such as weed control, crop protection, or crop ...

  3. Research Progress on the use of Plant Allelopathy in Agriculture and the Physiological and Ecological Mechanisms of Allelopathy.

    Science.gov (United States)

    Cheng, Fang; Cheng, Zhihui

    2015-01-01

    Allelopathy is a common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms. These biochemicals are known as allelochemicals and have beneficial or detrimental effects on target organisms. Plant allelopathy is one of the modes of interaction between receptor and donor plants and may exert either positive effects (e.g., for agricultural management, such as weed control, crop protection, or crop re-establishment) or negative effects (e.g., autotoxicity, soil sickness, or biological invasion). To ensure sustainable agricultural development, it is important to exploit cultivation systems that take advantage of the stimulatory/inhibitory influence of allelopathic plants to regulate plant growth and development and to avoid allelopathic autotoxicity. Allelochemicals can potentially be used as growth regulators, herbicides, insecticides, and antimicrobial crop protection products. Here, we reviewed the plant allelopathy management practices applied in agriculture and the underlying allelopathic mechanisms described in the literature. The major points addressed are as follows: (1) Description of management practices related to allelopathy and allelochemicals in agriculture. (2) Discussion of the progress regarding the mode of action of allelochemicals and the physiological mechanisms of allelopathy, consisting of the influence on cell micro- and ultra-structure, cell division and elongation, membrane permeability, oxidative and antioxidant systems, growth regulation systems, respiration, enzyme synthesis and metabolism, photosynthesis, mineral ion uptake, protein and nucleic acid synthesis. (3) Evaluation of the effect of ecological mechanisms exerted by allelopathy on microorganisms and the ecological environment. (4) Discussion of existing problems and proposal for future research directions in this field to provide a useful reference for future studies on plant

  4. The impact of microbial biotransformation of catechin in enhancing the allelopathic effects of Rhododendron formosanum.

    Science.gov (United States)

    Wang, Chao-Min; Li, Tsai-Chi; Jhan, Yun-Lian; Weng, Jen-Hsien; Chou, Chang-Hung

    2013-01-01

    Rhododendron formosanum is distributed widely in the central mountains in Taiwan and the major allelopathic compound in the leaves has been identified as (-)-catechin, which is also a major allelochemical of an invasive spotted knapweed in North America. Soil microorganisms play key roles in ecosystems and influence various important processes, including allelopathy. However, no microorganism has been identified as an allelochemical mediator. This study focused on the role of microorganisms in the allelopathic effects of R. formosanum. The microorganism population in the rhizosphere of R. formosanum was investigated and genetic analysis revealed that the predominant genera of microorganisms in the rhizosphere of R. formosanum were Pseudomonas, Herbaspirillum, and Burkholderia. The dominant genera Pseudomonas utilized (-)-catechin as the carbon source and catalyzed the conversion of (-)-catechin into protocatechuic acid in vitro. The concentrations of allelochemicals in the soil were quantified by liquid chromatography-electrospray ionization/tandem mass spectrometry. The concentration of (-)-catechin in the soil increased significantly during the extreme rainfall in the summer season and suppressed total bacterial populations. Protocatechuic acid accumulation was observed while total bacterial populations increased abundantly in both laboratory and field studies. Allelopathic interactions were tested by evaluating the effects of different allelochemicals on the seed germination, radicle growth, and photosynthesis system II of lettuce. Protocatechuic acid exhibited higher phytotoxicity than (-)-catechin did and the effect of (-)-catechin on the inhibition of seed germination was enhanced by combining it with protocatechuic acid at a low concentration. This study revealed the significance of the allelopathic interactions between R. formosanum and microorganisms in the rhizosphere. These findings demonstrate that knowledge regarding the precise biotransformation

  5. Effects of three macroalgae, Ulva linza (Chlorophyta), Corallina pilulifera (Rhodophyta) and Sargassum thunbergii (Phaeophyta) on the growth of the red tide microalga Prorocentrum donghaiense under laboratory conditions

    Science.gov (United States)

    Wang, Renjun; Xiao, Hui; Wang, You; Zhou, Wenli; Tang, Xuexi

    2007-10-01

    Allelopathic effects of several concentrations of fresh tissue and dry powder of three macroalgae, Ulva linza, Corallina pilulifera and Sargassum thunbergii, on the red tide microalga Prorocentrum donghaiense were evaluated in microcosms. Preliminary studies on the algicidal effects of one aqueous and four organic solvent extracts from the macroalgae on the microalga were carried out to confirm the existence of allelochemicals in the tissues of the macroalgae. The effects of macroalgal culture medium filtrate on P. donghaiense were investigated using initial or semi-continuous filtrate addition. Furthermore, the potential effects of the microalga on these three macroalgae were also tested. The results of the microcosm assay showed that the growth of P. donghaiense was strongly inhibited by using fresh tissues and dry powder of the three macroalgae. Both aqueous and methanol extracts of the macroalgae had strong growth inhibitory effects on P. donghaiense, while the other three organic solvent extracts (acetone, ether and chloroform) had no apparent effect on its growth; this suggested that the allelochemicals from these three macroalga had relatively high polarities. The three macroalgal culture medium filtrates exhibited apparent growth inhibitory effect on the microalgae under initial or semi-continuous addition, which suggested that the cells of P. donghaiense are sensitive to the allelochemicals. In contrast, P. donghaiense had no apparent effect on the growth of the macroalgae in coexistence experiment.

  6. Allelopathic inhibition on red tide microalgae Skeletonema costatum by five macroalgal extracts

    Institute of Scientific and Technical Information of China (English)

    Zhen AN; Zhenyu WANG; Fengmin LI; Zhijia TIAN; Hongying HU

    2008-01-01

    This study aims to identify effective antialgal allelochemicals from marine macroalgae that inhibit the growth of red tide-,microalgae. Practically, new algicidal agents were developed to control red tide. The growth inhibitory effects of 5 marinemacroalgae Porphyra tenera, Laminaria japonica, Ulva pertusa, Enteromorpha cla- thrata, and Undaria pinnatifida on Skeletonema costatum were evaluated by adding crude seawater extracts of macroalgal dry tissue into the culture medium containing S. costatum. The half-effective concentrations at 120 h (EC50, 120h) of the seawater extracts were 0.6, 0.9, 1.0, 1.0, and 4.7 g/L for the five macroalgae above, respect-ively. E. clathrata, L. japonica and U. pertusa showed strong allelopathic effect on the growth of S. costatum. There have been no previous reports with regard to the allelopathic effects of the former two macroalgae so far. The possible allelochemicals of 21 compounds of the E. clathrata were detected using Gas chromatography-mass spectrometry (GC-MS) analysis. Unsaturated fatty acids, acrylic acid (C3H4O2), and linolenic acid (C18H30O2) were the most likely allelochemicals in E. clathrata.

  7. Allelopathy-mediated Competition in Microbial Mats from Antarctic Lakes.

    Science.gov (United States)

    Slattery, Marc; Lesser, Michael P

    2017-02-18

    Microbial mats are vertically stratified communities that host a complex consortium of microorganisms, dominated by cyanobacteria, that compete for available nutrients and environmental niches, within these extreme habitats. The Antarctic Dry Valleys near McMurdo Sound include a series of lakes within the drainage basin that are bisected by glacial traverses. These lakes are traditionally independent, but recent increases in glacial melting have allowed two lakes (Chad and Hoare) to become connected by a meltwater stream. Microbial mats were collected from these lakes, and cultured under identical conditions at the McMurdo Station laboratory. Replicate pairings of the microbial mats exhibited consistent patterns of growth inhibition indicative of competitive dominance. Natural products were extracted from the microbial mats, and a disc diffusion assay was utilized to show that allelochemical compounds mediate competitive interactions. Both microscopy and 16S rRNA sequencing show that these mats contain significant populations of cyanobacteria known to produce allelochemicals. Two compounds were isolated from these microbial mats that might be important in the chemical ecology of these psychrophiles. In other disc:mat pairings, including extract versus mat of origin, the allelochemicals exhibited no effect. Taken together, these results indicate that Antarctic lake microbial mats can compete via allelopathy.

  8. Unravelling the beneficial role of microbial contributors in reducing the allelopathic effects of weeds.

    Science.gov (United States)

    Mishra, Sandhya; Upadhyay, Ram Sanmukh; Nautiyal, Chandra Shekhar

    2013-07-01

    The field of allelopathy is one of the most fascinating but controversial processes in plant ecology that offers an exciting, interdisciplinary, complex, and challenging study. In spite of the established role of soil microbes in plant health, their role has also been consolidated in studies of allelopathy. Moreover, allelopathy can be better understood by incorporating soil microbial ecology that determines the relevance of allelopathy phenomenon. Therefore, while discussing the role of allelochemicals in plant-plant interactions, the dynamic nature of soil microbes should not be overlooked. The occurrence and toxicity of allelochemicals in soil depend on various factors, but the type of microflora in the surroundings plays a crucial role because it can interfere with its allelopathic nature. Such microbes could be of prime importance for biological control management of weeds reducing the cost and ill effects of chemical herbicides. Among microbes, our main focus is on bacteria--as they are dominant among other microbes and are being used for enhancing crop production for decades--and fungi. Hence, to refer to both bacteria and fungi, we have used the term microbes. This review discusses the beneficial role of microbes in reducing the allelopathic effects of weeds. The review is mainly focused on various functions of bacteria in (1) reducing allelopathic inhibition caused by weeds to reduce crop yield loss, (2) building inherent defense capacity in plants against allelopathic weed, and (3) deciphering beneficial rhizospheric process such as chemotaxis/biofilm, degradation of toxic allelochemicals, and induced gene expression.

  9. Assays of the production of harmful substances by genetically modified oilseed rape (Brassica napus L.) plants in accordance with regulations for evaluating the impact on biodiversity in Japan.

    Science.gov (United States)

    Asanuma, Yoko; Jinkawa, Tomoe; Tanaka, Hidenori; Gondo, Takahiro; Zaita, Norihiro; Akashi, Ryo

    2011-02-01

    Environmental risk assessment of transgenic crops is implemented under the Cartagena Protocol domestic law in accordance with guidelines for implementing the assessment established by the Ministry of Agriculture, Forestry and Fisheries (MAFF) and the Ministry of Environment (MOE) in Japan. Environmental risk assessments of transgenic crops are implemented based on the concept of 'substantial equivalence' to conventional crops. A unique requirement in Japan to monitor the production of harmful substances, or allelochemicals, is unparalleled in other countries. The potential for allelochemicals to be secreted from the roots of transgenic crops to affect other plants or soil microflora or for substances in the plant body to affect other plants after dying out must be evaluated. We evaluated the allelopathic potential of seven transgenic oilseed rape (Brassica napus L.) lines that express glufosinate tolerance in terms of substantial equivalence to conventional oilseed rape lines, and established evaluation methods. Our results indicate no potential production of allelochemicals for any of the seven transgenic oilseed rape lines compared with conventional oilseed rape lines.

  10. Allelopathy of Bracken Fern (Pteridium arachnoideum): New Evidence from Green Fronds, Litter, and Soil

    Science.gov (United States)

    Juliano Gualtieri, Sonia Cristina; Rodrigues-Filho, Edson; Macías, Francisco Antonio

    2016-01-01

    The neotropical bracken fern Pteridium arachnoideum (Kaulf.) Maxon. (Dennstaedtiaceae) is described as an aggressive pioneer plant species. It invades abandoned or newly burned areas and represents a management challenge at these invaded sites. Native to the Atlantic Forest and Cerrado (Tropical Savanna) Brazilian biomes, P. arachnoideum has nevertheless become very problematic in these conservation hotspots. Despite some reports suggesting a possible role of allelopathy in this plant’s dominance, until now there has been little evidence of isolated and individually identified compounds with phytotoxic activities present in its tissues or in the surrounding environment. Thus, the aim of this study was to investigate the allelopathic potential of P. arachnoideum by isolating and identifying any secondary metabolites with phytotoxic activity in its tissues, litter, and soil. Bioguided phytochemical investigation led to the isolation and identification of the proanthocyanidin selligueain A as the major secondary compound in the green fronds and litter of this fern. It is produced by P. arachnoideum in its green fronds, remains unaltered during the senescence process, and is the major secondary compound present in litter. Selligueain A showed phytotoxic activity against the selected target species sesame (Sesamum indicum) early development. In particular, the compound inhibited root and stem growth, and root metaxylem cell size but did not affect chlorophyll content. This compound can be considered as an allelochemical because it is present in the soil under P. arachnoideum patches as one of the major compounds in the soil solution. This is the first report of the presence of selligueain A in any member of the Dennstaedtiaceae family and the first time an isolated and identified allelochemical produced by members of the Pteridium species complex has been described. This evidence of selligueain A as a putative allelochemical of P. arachnoideum reinforces the role of

  11. Allelopathy of Bracken Fern (Pteridium arachnoideum): New Evidence from Green Fronds, Litter, and Soil.

    Science.gov (United States)

    de Jesus Jatoba, Luciana; Varela, Rosa Maria; Molinillo, José Maria Gonzalez; Ud Din, Zia; Juliano Gualtieri, Sonia Cristina; Rodrigues-Filho, Edson; Macías, Francisco Antonio

    2016-01-01

    The neotropical bracken fern Pteridium arachnoideum (Kaulf.) Maxon. (Dennstaedtiaceae) is described as an aggressive pioneer plant species. It invades abandoned or newly burned areas and represents a management challenge at these invaded sites. Native to the Atlantic Forest and Cerrado (Tropical Savanna) Brazilian biomes, P. arachnoideum has nevertheless become very problematic in these conservation hotspots. Despite some reports suggesting a possible role of allelopathy in this plant's dominance, until now there has been little evidence of isolated and individually identified compounds with phytotoxic activities present in its tissues or in the surrounding environment. Thus, the aim of this study was to investigate the allelopathic potential of P. arachnoideum by isolating and identifying any secondary metabolites with phytotoxic activity in its tissues, litter, and soil. Bioguided phytochemical investigation led to the isolation and identification of the proanthocyanidin selligueain A as the major secondary compound in the green fronds and litter of this fern. It is produced by P. arachnoideum in its green fronds, remains unaltered during the senescence process, and is the major secondary compound present in litter. Selligueain A showed phytotoxic activity against the selected target species sesame (Sesamum indicum) early development. In particular, the compound inhibited root and stem growth, and root metaxylem cell size but did not affect chlorophyll content. This compound can be considered as an allelochemical because it is present in the soil under P. arachnoideum patches as one of the major compounds in the soil solution. This is the first report of the presence of selligueain A in any member of the Dennstaedtiaceae family and the first time an isolated and identified allelochemical produced by members of the Pteridium species complex has been described. This evidence of selligueain A as a putative allelochemical of P. arachnoideum reinforces the role of

  12. Dose-response-a challenge for allelopathy?

    Science.gov (United States)

    Belz, Regina G; Hurle, Karl; Duke, Stephen O

    2005-04-01

    The response of an organism to a chemical depends, among other things, on the dose. Nonlinear dose-response relationships occur across a broad range of research fields, and are a well established tool to describe the basic mechanisms of phytotoxicity. The responses of plants to allelochemicals as biosynthesized phytotoxins, relate as well to nonlinearity and, thus, allelopathic effects can be adequately quantified by nonlinear mathematical modeling. The current paper applies the concept of nonlinearity to assorted aspects of allelopathy within several bioassays and reveals their analysis by nonlinear regression models. Procedures for a valid comparison of effective doses between different allelopathic interactions are presented for both, inhibitory and stimulatory effects. The dose-response applications measure and compare the responses produced by pure allelochemicals [scopoletin (7-hydroxy-6-methoxy-2H-1-benzopyran-2-one); DIBOA (2,4-dihydroxy-2H-1,4-benzoxaxin-3(4H)-one); BOA (benzoxazolin-2(3H)-one); MBOA (6-methoxy-benzoxazolin-2(3H)-one)], involved in allelopathy of grain crops, to demonstrate how some general principles of dose responses also relate to allelopathy. Hereupon, dose-response applications with living donor plants demonstrate the validity of these principles for density-dependent phytotoxicity of allelochemicals produced and released by living plants (Avena sativa L., Secale cereale L., Triticum L. spp.), and reveal the use of such experiments for initial considerations about basic principles of allelopathy. Results confirm that nonlinearity applies to allelopathy, and the study of allelopathic effects in dose-response experiments allows for new and challenging insights into allelopathic interactions.

  13. The effect of water extracts from leaves of Festuca rubra, F. ovina and F. Arundinacea on the initial growth and development of other grass species

    Directory of Open Access Journals (Sweden)

    Halina Lipińska

    2013-07-01

    Full Text Available The allelopathic effect of plants is one of the least known factors determining the stability of lawn swards. Leaves are a rich source of allelopathic substances. Washed out by rain or dew drops, or released during biomass decomposition, these substances can impact plants. In practice, cut sward is often left on the lawn surface and can have an allelopathic effect on regrowing plants. The effect of released allelochemicals depends on many factors, including their concentration. Hence, in order to maintain the high functional properties of the lawn, information is needed on the critical concentrations of allelochemicals inhibiting plant growth and development. Laboratory research was thus undertaken (on Petri dishes to evaluate the effect of various water extracts of leaves of selected lawn grass cultivars. The following cultivars were the donors: 'Areta', 'Nimba', 'Olivia' (Festuca rubra; 'Espro', 'Pintor' (F. ovina,and 'Asterix' (F. arundinacea, while the acceptors were: 'Niwa' (Agrostis capillaris, 'Asterix' (Festuca arundinacea, 'Espro' (F. ovina, 'Areta' (F. rubra, 'Stadion' (Lolium perenne, and 'Bila' (Poa pratensis – the species frequently sown in lawns. In the control treatments, distilled water was applied to the substrate. The experiment revealed that the effect of water extracts of leaves varied depending on their concentration and donor variety as well as the sensitivity of the acceptor (the test plant. In comparison with the control treatments, the strongest negative impact was caused by the cultivars 'Olivia' (F. rubraand 'Pintor' (F. ovina, followed by 'Asterix' (F. arundinacea. Among the acceptors, the greatest sensitivity to the presence of allelochemicals was shown by A. capillaris, and the smallest by F. arundinacea. .

  14. Spatial and temporal dynamics of root exudation: how important is heterogeneity in allelopathic interactions?

    Science.gov (United States)

    Weidenhamer, Jeffrey D; Mohney, Brian K; Shihada, Nader; Rupasinghe, Maduka

    2014-08-01

    Understanding allelopathy has been hindered by the lack of methods available to monitor the dynamics of allelochemicals in the soil. Previous work has demonstrated the feasibility of using polydimethylsiloxane (PDMS) microtubing (silicone tubing microextraction, or STME) to construct sampling devices to monitor the release of lipophilic allelochemicals from plant roots. The objective of this study was to use such sampling devices to intensively monitor thiophene fluxes beneath marigolds over several weeks to gain insight into the magnitude of temporal and spatial heterogeneity in these fluxes. Marigolds were grown in rhizoboxes (20.5 x 20.5 x 3.0 cm) with 16 individual STME samplers per box. Thiophene sampling and HPLC analysis began 45 days after planting. At the end of the study, roots around each sampler were analyzed by HPLC. Results confirmed the tremendous spatial and temporal heterogeneity in thiophene production seen in our previous studies. STME probes show that thiophene concentrations generally increase over time; however, these effects were sampling-port specific. When sampling ports were monitored at 12 h intervals, fluxes at each port ranged from 0 to 2,510 ng day(-1). Fluxes measured over daylight hr averaged 29 % higher than those measured overnight. Fluxes were less than 1 % on average of the total thiophene content of surrounding roots. While the importance of such heterogeneity, or "patchiness", in the root zone has been recognized for soil nutrients, the potential importance in allelopathic interactions has seldom been considered. The reasons for this variability are unclear, but are being investigated. Our results demonstrate that STME can be used as a tool to provide a more finely-resolved picture of allelochemical dynamics in the root zone than has previously been available.

  15. Sorghum allelopathy--from ecosystem to molecule.

    Science.gov (United States)

    Weston, Leslie A; Alsaadawi, Ibrahim S; Baerson, Scott R

    2013-02-01

    Sorghum allelopathy has been reported in a series of field experiments following sorghum establishment. In recent years, sorghum phytotoxicity and allelopathic interference also have been well-described in greenhouse and laboratory settings. Observations of allelopathy have occurred in diverse locations and with various sorghum plant parts. Phytotoxicity has been reported when sorghum was incorporated into the soil as a green manure, when residues remained on the soil surface in reduced tillage settings, or when sorghum was cultivated as a crop in managed fields. Allelochemicals present in sorghum tissues have varied with plant part, age, and cultivar evaluated. A diverse group of sorghum allelochemicals, including numerous phenolics, a cyanogenic glycoside (dhurrin), and a hydrophobic p-benzoquinone (sorgoleone) have been isolated and identified in recent years from sorghum shoots, roots, and root exudates, as our capacity to analyze and identify complex secondary products in trace quantities in the plant and in the soil rhizosphere has improved. These allelochemicals, particularly sorgoleone, have been widely investigated in terms of their mode(s) of action, specific activity and selectivity, release into the rhizosphere, and uptake and translocation into sensitive indicator species. Both genetics and environment have been shown to influence sorgoleone production and expression of genes involved in sorgoleone biosynthesis. In the soil rhizosphere, sorgoleone is released continuously by living root hairs where it accumulates in significant concentrations around its roots. Further experimentation designed to study the regulation of sorgoleone production by living sorghum root hairs may result in increased capacity to utilize sorghum cover crops more effectively for suppression of germinating weed seedlings, in a manner similar to that of soil-applied preemergent herbicides like trifluralin.

  16. Research advance on influencing factors of plant allelopathy%植物化感作用影响因素研究进展

    Institute of Scientific and Technical Information of China (English)

    拱健婷; 张子龙

    2015-01-01

    化感现象广泛存在于植物界,植物之间的化感作用对生态系统有着不可忽视的影响。综合近年的文献,试图对影响植物化感作用的重要因素进行总结,旨在为探究植物化感作用机制、合理利用化感作用提供一定的理论参考。当前研究表明:1)遗传因素(供体种间差异、供体种内品种间差异、受体植物)影响植物的化感作用;2)植物生长阶段、不同营养器官化感物质的种类含量有差异,化感作用受此因素影响;3)环境条件,如生境、光照、温度、水分、土壤结构、营养条件等在不同程度上影响植物化感物质的产生、释放及其效应;4)动物侵害导致植物化感物质合成、释放能力增强,以抵御外界干扰环境,微生物参与化感物质的降解过程,从而影响其最终去向。最后对植物化感作用的研究进行了展望。%Allelopathy universally exists in the world, it would have a negligible impact among plants in the ecosystem. The current studies showed that plant allelopathy was genetic affected by the factors such as donor species difference, donor intraspecific differ-ences between species, receptors plant. Allelopathy was also affected by those like species of plant growth stage and the content of different vegetative organs of allelochemicals. Environmental conditions, such as habitat, illumination, temperature, moisture, soil structure and nutrient conditions affected the level, release and effect of plant allelochemicals in different extent. Animal invasion could cause the plant to synthesize and release the allelochemicals for enhancing ability to resist external interference. The microbial activities could control the pathway of the allelochemicals degradation. Also, the prospect of allelopathy research were discussed at last.

  17. Benzoxazinoids in Root Exudates of Maize Attract Pseudomonas putida to the Rhizosphere

    OpenAIRE

    Neal, Andrew L.; Shakoor Ahmad; Ruth Gordon-Weeks; Jurriaan Ton

    2012-01-01

    Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs) have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere w...

  18. Evolution of substrate recognition sites (SRSs) in cytochromes P450 from Apiaceae exemplified by the CYP71AJ subfamily

    DEFF Research Database (Denmark)

    Dueholm, Bjørn; Krieger, Celia; Drew, Damian;

    2015-01-01

    Background: Large proliferations of cytochrome P450 encoding genes resulting from gene duplications can be termed as 'blooms', providing genetic material for the genesis and evolution of biosynthetic pathways. Furanocoumarins are allelochemicals produced by many of the species in Apiaceaous plants...... and four other subclades were identified and shown to be part of two distinct clades within the CYP71AJ subfamily. The subclades show significant variability within their substrate recognition sites between the clades, suggesting different biochemical functions and providing insights into the evolution...

  19. Isolation of phytotoxic compounds from tree-of-heaven (Ailanthus altissima swingle).

    Science.gov (United States)

    De Feo, Vincenzo; De Martino, Laura; Quaranta, Emilia; Pizza, Cosimo

    2003-02-26

    The aqueous root extract of Ailanthus altissima showed allelopathic activity against radish (Raphanus sativus L. cv. "Saxa"), garden cress (Lepidium sativum L.), and purslane (Portulaca oleracea L.) seeds. A bioassay-oriented purification of active extracts, chromatographic fractions, and compounds demonstrated dose-dependent activity on germination and radicle growth of test seeds; radish seed was the most sensitive to allelochemicals. Active compounds have been isolated: ailanthone, ailanthinone, chaparrine, and ailanthinol B (quassinoid derivatives); the alkaloid 1-methoxycanthin-6-one is not active. The compound with greatest inhibitory activity is ailanthone. The data obtained suggest a possible use of tree-of-heaven root extracts or of its active constituents as natural herbicides.

  20. Ecological Effects of Allelopathic Plants

    DEFF Research Database (Denmark)

    Kruse, M.; Strandberg, M.; Strandberg, B.

    with the environment through spread of GM-plants or transgenes outside agricultural areas. The last chapter discuss GM-allelopathic plants in relation to the ecological risk assessment. Preface: This report is based on a literature review on allelopathy from an ecological impact point of view carried out in 1999...... on allelopathy in these crops. It discusses the ecological effects of allelopathic plants in natural ecosystems and factors of importance for the effects of these plants are pointed out. Finally the report presents suggestions for an ecological risk assessment of crops with an enhanced release of allelochemicals...

  1. The influence of dietary α-solanine on the waxmoth Galleria mellonella L.

    Science.gov (United States)

    Büyükgüzel, Ender; Büyükgüzel, Kemal; Erdem, Meltem; Adamski, Zbigniew; Adamski, Zbigniew; Marciniak, Pawel; Ziemnicki, Kazimierz; Ventrella, Emanuela; Scrano, Laura; Bufo, Sabino Aurelio

    2013-05-01

    Plant allelochemicals are nonnutritional chemicals that interfere with the biology of herbivores. We posed the hypothesis that ingestion of a glycoalkaloid allelochemical, α-solanine, impairs biological parameters of greater wax moths Galleria mellonella. To test this idea, we reared wax moths on artificial diets with 0.015, 0.15, or 1.5 mg/100 g diet of α-solanine. Addition of α-solanine to the diet affected survival of seventh-instar larvae, pupae, and adults; and female fecundity and fertility. The diet containing the highest α-solanine concentration led to decreased survivorship, fecundity, and fertility. The diets supplemented with α-solanine led to increased malondialdehyde and protein carbonyl contents in midgut and fat body and the effect was dose-dependent. Dietary α-solanine led to increased midgut glutathione S-transferase activity and to decreased fat body glutathione S-transferase activitiy. We infer from these findings that α-solanine influences life history parameters and antioxidative enzyme activities in the midgut and fat body of G. mellonella.

  2. Allelopathic control of cyanobacterial blooms by periphyton biofilms.

    Science.gov (United States)

    Wu, Yonghong; Liu, Jiantong; Yang, Linzhang; Chen, Hong; Zhang, Shanqing; Zhao, Huijun; Zhang, Naiming

    2011-03-01

    Periphyton biofilms are natural mixtures comprised of photoautotrophic and heterotrophic complex microorganisms. In this work, the inhibition effects of periphyton biofilms on cyanobacterial blooms were studied in pilot and field trials. Results show that the cyanobacterial species responsible for the blooms had an upper nutrient concentration threshold, below which it could not effectively compete with other organisms in the periphyton. The disappearance of the cyanobacterial blooms was due to the allelopathy between the cyanobacteria and periphyton biofilm. In particular, it was found that the periphyton biofilm could produce water-soluble allelochemicals such as indole and 3-oxo-α-ionone to significantly inhibit the growth of the cyanobacteria. These allelochemicals are able to damage the thylakoid membranes of the cyanobacteria, interrupt the electron transport in photosystem II, decrease effective quantum yields, and eventually lead to the failure of photosynthesis. A comprehensive discussion on the ecological consequences of these findings is also presented. This work demonstrates the potential of periphyton biofilm to be used as an environmentally friendly ecological engineering solution for (i) the control of cyanobacterial blooms and (ii) a transitional means for the construction of beneficial conditions for ecosystem restoration. In addition, this work provides significant insights into the competitive relationships between algae and biofilms.

  3. Do different casein concentrations increase the adverse effect of rutin on the biology of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae)?

    Science.gov (United States)

    Salvador, Mariana C; Boiça, Arlindo L; de Oliveira, Maria C N; da Graça, José P; da Silva, Débora M; Hoffmann-Campo, Clara B

    2010-01-01

    The flavonoid rutin is recognized as playing an important role in the protection of plants against lepidopterans. Bioassays with this compound are generally carried out using artificial diets. Proteins of high energy value, such as casein, are important ingredients of insect artificial diets as a source of essential amino acids. However, such proteins can generally increase the allelochemical activity. Our objective was to evaluate the effects of rutin on larvae of the velvetbean caterpillar Anticarsia gemmatalis Hübner by incorporating this allelochemical into diets with different concentrations of casein. Three casein concentrations (0, 7 g, or 14 g) combined with none, 0.65%, or 1.30% of rutin were added to the rearing diet and offered to the larvae from hatching to pupation. Rutin negatively affected larval development, the amount of food consumed, and pupal weight of A. gemmatalis. These negative effects were clearly seen in insects fed on diets with 7 g of casein to which any concentration of rutin was added. The effects of rutin when added to the diets without casein were stronger than in diets containing a suitable amount of casein (14 g). The greater negative effects of rutin in diets containing suboptimal concentrations of casein indicate that casein can increase the effects of rutin only when the diets are nutritionally unsuitable for insect development.

  4. Eating chemically defended prey: alkaloid metabolism in an invasive ladybird predator of other ladybirds (Coleoptera: Coccinellidae).

    Science.gov (United States)

    Sloggett, J J; Davis, A J

    2010-01-15

    By comparison with studies of herbivore physiological adaptation to plant allelochemicals, work on predator physiological adaptation to potentially toxic prey has been very limited. Such studies are important in understanding how evolution could shape predator diets. An interesting question is the specificity of predator adaptation to prey allelochemicals, given that many predators consume diverse prey with different chemical defences. The ladybird Harmonia axyridis, an invasive species in America, Europe and Africa, is considered a significant predatory threat to native invertebrates, particularly other aphid-eating ladybirds of which it is a strong intraguild predator. Although ladybirds possess species-specific alkaloid defences, H. axyridis exhibits high tolerance for allospecific ladybird prey alkaloids. Nonetheless, it performs poorly on species with novel alkaloids not commonly occurring within its natural range. We examined alkaloid fate in H. axyridis larvae after consumption of two other ladybird species, one containing an alkaloid historically occurring within the predator's native range (isopropyleine) and one containing a novel alkaloid that does not (adaline). Our results indicate that H. axyridis rapidly chemically modifies the alkaloid to which it has been historically exposed to render it less harmful: this probably occurs outside of the gut. The novel, more toxic alkaloid persists in the body unchanged for longer. Our results suggest metabolic alkaloid specialisation, in spite of the diversity of chemically defended prey that the predator consumes. Physiological adaptations appear to have made H. axyridis a successful predator of other ladybirds; however, limitations are imposed by its physiology when it eats prey with novel alkaloids.

  5. Comparative Studies on the Allelopathic Effects of Ulva pertusa Kjellml, Corallina pilulifera Postl et Ruprl, and Sargassum thunbergii Mertl O. Kuntze on Skeletonema costatum (Grev.) Cleve

    Institute of Scientific and Technical Information of China (English)

    Ren-Jun Wang; Hui Xiao; Pei-Yu Zhang; Liang Qu; Heng-Jiang Cai; Xue-Xi Tang

    2006-01-01

    In the present study, we evaluated the allelopathic effects of three macroalgae, namely Ulva pertusa Kjellml,Corallina pilulifera Postl et Ruprl, and Sargassum thunbergii Mertl O. Kuntze, on the growth of the microalga Skeletonema costatum (Grev.) Creve using culture systems in which the algae coexisted. The effects of the macroalgal culture medium filtrate on S. costatum were also investigated. Moreover, isolated co-culture systems were built to confirm the existence of allelochemicals and preclude growth inhibition by direct contact. The coexistence assay data demonstrated that the growth of S. costatum was strongly inhibited when fresh tissues, dry powder and aqueous extracts were used; the allelochemicals were lethal to S.costatum at relatively higher concentrations. The effects of the macroalgal culture medium filtrate on the microalga showed both species specificity and complexity. The inhibitory effect of fresh macroalgal tissue and culture medium filtrate on the microalga was due to the alleochemicals released by the macroalgae.The results of the present study show that the allelopathic effects of macroalgae on the microalga are complex. The present study could shed light onto the basis of the interaction between macro- and microalgae.

  6. Molecular mechanisms of metabolic resistance to synthetic and natural xenobiotics.

    Science.gov (United States)

    Li, Xianchun; Schuler, Mary A; Berenbaum, May R

    2007-01-01

    Xenobiotic resistance in insects has evolved predominantly by increasing the metabolic capability of detoxificative systems and/or reducing xenobiotic target site sensitivity. In contrast to the limited range of nucleotide changes that lead to target site insensitivity, many molecular mechanisms lead to enhancements in xenobiotic metabolism. The genomic changes that lead to amplification, overexpression, and coding sequence variation in the three major groups of genes encoding metabolic enzymes, i.e., cytochrome P450 monooxygenases (P450s), esterases, and glutathione-S-transferases (GSTs), are the focus of this review. A substantial number of the adaptive genomic changes associated with insecticide resistance that have been characterized to date are transposon mediated. Several lines of evidence suggest that P450 genes involved in insecticide resistance, and perhaps insecticide detoxification genes in general, may share an evolutionary association with genes involved in allelochemical metabolism. Differences in the selective regime imposed by allelochemicals and insecticides may account for the relative importance of regulatory or structural mutations in conferring resistance.

  7. Overexpression of glutathione transferase E7 in Drosophila differentially impacts toxicity of organic isothiocyanates in males and females.

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    Aslam M A Mazari

    Full Text Available Organic isothiocyanates (ITCs are allelochemicals produced by plants in order to combat insects and other herbivores. The compounds are toxic electrophiles that can be inactivated and conjugated with intracellular glutathione in reactions catalyzed by glutathione transferases (GSTs. The Drosophila melanogaster GSTE7 was heterologously expressed in Escherichia coli and purified for functional studies. The enzyme showed high catalytic activity with various isothiocyanates including phenethyl isothiocyanate (PEITC and allyl isothiocyanate (AITC, which in millimolar dietary concentrations conferred toxicity to adult D. melanogaster leading to death or a shortened life-span of the flies. In situ hybridization revealed a maternal contribution of GSTE7 transcripts to embryos, and strongest zygotic expression in the digestive tract. Transgenesis involving the GSTE7 gene controlled by an actin promoter produced viable flies expressing the GSTE7 transcript ubiquitously. Transgenic females show a significantly increased survival when subjected to the same PEITC treatment as the wild-type flies. By contrast, transgenic male flies show a significantly lower survival rate. Oviposition activity was enhanced in transgenic flies. The effect was significant in transgenic females reared in the absence of ITCs as well as in the presence of 0.15 mM PEITC or 1 mM AITC. Thus the GSTE7 transgene elicits responses to exposure to ITC allelochemicals which differentially affect life-span and fecundity of male and female flies.

  8. Is Allelopathic Activity of Ipomoea murucoides Induced by Xylophage Damage?

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    Alejandro Flores-Palacios

    Full Text Available Herbivory activates the synthesis of allelochemicals that can mediate plant-plant interactions. There is an inverse relationship between the activity of xylophages and the abundance of epiphytes on Ipomoea murucoides. Xylophagy may modify the branch chemical constitution, which also affects the liberation of allelochemicals with defense and allelopathic properties. We evaluated the bark chemical content and the effect of extracts from branches subjected to treatments of exclusion, mechanical damage and the presence/absence of epiphytes, on the seed germination of the epiphyte Tillandsia recurvata. Principal component analysis showed that branches without any treatment separate from branches subjected to treatments; damaged and excluded branches had similar chemical content but we found no evidence to relate intentional damage with allelopathy; however 1-hexadecanol, a defense volatile compound correlated positively with principal component (PC 1. The chemical constitution of branches subject to exclusion plus damage or plus epiphytes was similar among them. PC2 indicated that palmitic acid (allelopathic compound and squalene, a triterpene that attracts herbivore enemies, correlated positively with the inhibition of seed germination of T. recurvata. Inhibition of seed germination of T. recurvata was mainly correlated with the increment of palmitic acid and this compound reached higher concentrations in excluded branches treatments. Then, it is likely that the allelopathic response of I. murucoides would increase to the damage (shade, load that may be caused by a high load of epiphytes than to damage caused by the xylophages.

  9. Allelopathic interactions between Prorocentrum micans and Skeletonema costatum or Karenia mikimotoi in laboratory cultures

    Science.gov (United States)

    Ji, Xiaoqing; Han, Xiaotian; Zheng, Li; Yang, Baijuan; Yu, Zhiming; Zou, Jingzhong

    2011-07-01

    Algal allelopathy is an ecological/physiological phenomenon that has focused attention on the interactions among algae and the production of algal toxins. We investigated the allelopathic interactions between the dinoflagellate genus Prorocentrum micans and diatom genus Skeletonema costatum and between P. micans and dinoflagellate genus Karenia mikimotoi using bi-algal cultures. Because the effects were species-specific and size-dependent, we evaluated the effect of different initial densities. At low densities of P. micans and high densities of S. costatum inoculated into the same medium, the growth of P. micans was weakly restrained, whereas the growth of S. costatum was significantly suppressed. S. costatum and K. mikimotoi were strongly inhibited by P. micans, in both the bi-algal cultures and enriched filtrates. Direct cell-to-cell contact was not necessary to gain a competitive advantage, thus, our results suggest that P. micans inhibited the growth of S. costatum and K. mikimotoi by the release of allelochemical(s). Last, a mathematical model was used to simulate growth and interactions between P. micans and S. costatum and between P. micans and K. mikimotoi in bi-algal cultures.

  10. Biochemical Impact of Fodder Galega (Galega orientalis Lam. on Agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Ligita Baležentienė

    2011-12-01

    Full Text Available Multifunctional allelochemicals activities stimulate an increase in an employment spectrum of biologically active compounds in biological farming. The understanding of the allelochemical action mechanisms makes it possible to use these compounds to enhance crop production and develop a more sustainable agriculture, including weed and pest control through crop rotations, residue management and a variety of approaches in bio-control. The aim of this research was to establish and to compare the total amount of phenolic compounds and allelopathic activity of the aqueous extracts produced of different shoot parts (leaves, stems, blossoms and seed and roots of new crop, namely fodder galega at their different growth stages. Biochemical impact of the aqueous extracts produced of fodder galega ground part and roots on the germination data of the test–object subjected significantly on the galega growth stage and extract concentration. The biochemical effect of all tested extracts and concentrations had the same tendency to inhibit the test–object seed germination. The extracts of the ground part were more toxic than those of roots and had a stronger suppressive effect on the test–plant germination. Phenols concentration and conventional coumarine unit (CCU content increased evenly in dependence on total phenols concentration at all plant development stages accordingly to the extracts concentration gradient. Phenols concentration as well as their activity of ground part and roots increased from shooting to flowering stage.

  11. Lichen secondary metabolites affect growth of Physcomitrella patens by allelopathy.

    Science.gov (United States)

    Goga, Michal; Antreich, Sebastian J; Bačkor, Martin; Weckwerth, Wolfram; Lang, Ingeborg

    2016-09-19

    Lichen secondary metabolites can function as allelochemicals and affect the development and growth of neighboring bryophytes, fungi, vascular plants, microorganisms, and even other lichens. Lichen overgrowth on bryophytes is frequently observed in nature even though mosses grow faster than lichens, but there is still little information on the interactions between lichens and bryophytes.In the present study, we used extracts from six lichen thalli containing secondary metabolites like usnic acid, protocetraric acid, atranorin, lecanoric acid, nortistic acid, and thamnolic acid. To observe the influence of these metabolites on bryophytes, the moss Physcomitrella patens was cultivated for 5 weeks under laboratory conditions and treated with lichen extracts. Toxicity of natural mixtures of secondary metabolites was tested at three selected doses (0.001, 0.01, and 0.1 %). When the mixture contained substantial amounts of usnic acid, we observed growth inhibition of protonemata and reduced development of gametophores. Significant differences in cell lengths and widths were also noticed. Furthermore, usnic acid had a strong effect on cell division in protonemata suggesting a strong impact on the early stages of bryophyte development by allelochemicals contained in the lichen secondary metabolites.Biological activities of lichen secondary metabolites were confirmed in several studies such as antiviral, antibacterial, antitumor, antiherbivore, antioxidant, antipyretic, and analgetic action or photoprotection. This work aimed to expand the knowledge on allelopathic effects on bryophyte growth.

  12. Is Allelopathic Activity of Ipomoea murucoides Induced by Xylophage Damage?

    Science.gov (United States)

    Flores-Palacios, Alejandro; Corona-López, Angélica María; Rios, María Yolanda; Aguilar-Guadarrama, Berenice; Toledo-Hernández, Víctor Hugo; Rodríguez-López, Verónica; Valencia-Díaz, Susana

    2015-01-01

    Herbivory activates the synthesis of allelochemicals that can mediate plant-plant interactions. There is an inverse relationship between the activity of xylophages and the abundance of epiphytes on Ipomoea murucoides. Xylophagy may modify the branch chemical constitution, which also affects the liberation of allelochemicals with defense and allelopathic properties. We evaluated the bark chemical content and the effect of extracts from branches subjected to treatments of exclusion, mechanical damage and the presence/absence of epiphytes, on the seed germination of the epiphyte Tillandsia recurvata. Principal component analysis showed that branches without any treatment separate from branches subjected to treatments; damaged and excluded branches had similar chemical content but we found no evidence to relate intentional damage with allelopathy; however 1-hexadecanol, a defense volatile compound correlated positively with principal component (PC) 1. The chemical constitution of branches subject to exclusion plus damage or plus epiphytes was similar among them. PC2 indicated that palmitic acid (allelopathic compound) and squalene, a triterpene that attracts herbivore enemies, correlated positively with the inhibition of seed germination of T. recurvata. Inhibition of seed germination of T. recurvata was mainly correlated with the increment of palmitic acid and this compound reached higher concentrations in excluded branches treatments. Then, it is likely that the allelopathic response of I. murucoides would increase to the damage (shade, load) that may be caused by a high load of epiphytes than to damage caused by the xylophages.

  13. Phenolics and plant allelopathy.

    Science.gov (United States)

    Li, Zhao-Hui; Wang, Qiang; Ruan, Xiao; Pan, Cun-De; Jiang, De-An

    2010-12-07

    Phenolic compounds arise from the shikimic and acetic acid (polyketide) metabolic pathways in plants. They are but one category of the many secondary metabolites implicated in plant allelopathy. Phenolic allelochemicals have been observed in both natural and managed ecosystems, where they cause a number of ecological and economic problems, such as declines in crop yield due to soil sickness, regeneration failure of natural forests, and replanting problems in orchards. Phenolic allelochemical structures and modes of action are diverse and may offer potential lead compounds for the development of future herbicides or pesticides. This article reviews allelopathic effects, analysis methods, and allelopathic mechanisms underlying the activity of plant phenolic compounds. Additionally, the currently debated topic in plant allelopathy of whether catechin and 8-hydroxyquinoline play an important role in Centaurea maculata and Centaurea diffusa invasion success is discussed. Overall, the main purpose of this review is to highlight the allelopacthic potential of phenolic compounds to provide us with methods to solve various ecology problems, especially in regard to the sustainable development of agriculture, forestry, nature resources and environment conservation.

  14. To survive or to slay: Resource-foraging role of metabolites implicated in allelopathy.

    Science.gov (United States)

    Tharayil, Nishanth

    2009-07-01

    The ecological relevance of allelopathy is highly debated due to the lack of phytotoxic concentrations of allelochemical in natural field conditions. Most of the putative allelochemicals are exuded at low concentrations, and subsequently undergo rapid chemical and biological degradation in soil matrices. At sub-toxic concentrations, due to hormesis effect, these compounds could possibly have a stimulatory effect on plant growth. Many of the suggested allelopathic compounds are chelants and can complex-with and mobilize metal ions in soil. These complexation reactions will detoxify the compound, but will increase the chemical-nutrient-foraging ability of the donor plant. The concentration in which these compounds are exuded matches with other similar secondary metabolites facilitating plant nutrient acquisition. Irrespective of whether the implicated PSMs facilitate donor plant in chemical nutrient-foraging or in poisoning the neighbors, the conferred advantage translates in terms of resource availability-in first case the donor enjoys uncontested nutrient uptake efficiency, where as in the latter the donor gain an uncontested access to resources. This further reaffirms the notion that resource competition and allelopathy are inextricable. Since most of the secondary metabolites could mobilize nutrients from soil, along with its phytotoxic effect, complementary self-facilitation roles of these compounds should be investigated.

  15. Phenolics and Plant Allelopathy

    Directory of Open Access Journals (Sweden)

    De-An Jiang

    2010-12-01

    Full Text Available Phenolic compounds arise from the shikimic and acetic acid (polyketide metabolic pathways in plants. They are but one category of the many secondary metabolites implicated in plant allelopathy. Phenolic allelochemicals have been observed in both natural and managed ecosystems, where they cause a number of ecological and economic problems, such as declines in crop yield due to soil sickness, regeneration failure of natural forests, and replanting problems in orchards. Phenolic allelochemical structures and modes of action are diverse and may offer potential lead compounds for the development of future herbicides or pesticides. This article reviews allelopathic effects, analysis methods, and allelopathic mechanisms underlying the activity of plant phenolic compounds. Additionally, the currently debated topic in plant allelopathy of whether catechin and 8-hydroxyquinoline play an important role in Centaurea maculata and Centaurea diffusa invasion success is discussed. Overall, the main purpose of this review is to highlight the allelopacthic potential of phenolic compounds to provide us with methods to solve various ecology problems, especially in regard to the sustainable development of agriculture, forestry, nature resources and environment conservation.

  16. Interspecific competition and allelopathic interaction between Karenia mikimotoi and Dunaliella salina in laboratory culture

    Science.gov (United States)

    He, Dong; Liu, Jiao; Hao, Qiang; Ran, Lihua; Zhou, Bin; Tang, Xuexi

    2016-03-01

    Algal allelopathy is a manifold ecological/physiological phenomenon that is focused on chemical interactions and autotoxicity. We investigated the allelopathic interactions between Karenia mikimotoi and Dunaliella salina in laboratory cultures based on diff erent temperature (15°C, 20°C, and 25°C) and lighting (40, 80, and 160 μmol/(m2·s)) conditions. The growth of D. salina in bi-algae culture (1:1 size/density) was significantly restrained. The results of cell-free filtrate culture indicate that direct cell-tocell contact was not necessary in interspecific competition. Further experimental results demonstrated that allelochemicals released from K. mikimotoi were markedly influenced by both temperature ( P =0.013) and irradiance ( P =0.003), resulting in diff erent growth characteristics of D. salina in filtrate mediums. Compared with the plateau period, K. mikimotoi exudates in the exponential phase had a stronger short-term inhibition effect on D. salina in normal conditions. A clear concentration-dependent relationship was observed in the effect of allelochemicals released from K. mikimotoi with low-promoting and high-repressing effects on D. Salina in a short time-scale. In addition, allelopathic substances remain stable and effective under high temperature and pressure stress. Many flocculent sediments adhering with D. salina cells were observed in all filtrate mediums, while the quantity and color depended on the original culture conditions.

  17. An Evaluation of Allelopathy in the Toxic Grassland Weed,Aconitum leucostomum%草原毒害草白喉乌头的化感作用

    Institute of Scientific and Technical Information of China (English)

    韩彩霞; 彭瑞娟; 邰凤姣; 张弛; 邵华

    2015-01-01

    采用培养皿滤纸法,研究白喉乌头根、茎、叶的粉末,三氯甲烷提取物及水提取物在不同浓度下(0.01、0.02、0.05、0.10 g/mL)对受体植物高羊茅、草地早熟禾、垂穗披碱草和蒲公英幼苗生长的影响。结果表明,白喉乌头根、茎、叶的不同处理对受体植物的根长和苗高均具有抑制作用,其中三氯甲烷提取物的作用最弱,粉末次之,水提取物的抑制作用最强,说明其主效化感物质为水溶性化合物。白喉乌头各部位的化感作用强度无本质差异,表明其化感物质在植株各部位均有分布。%The allelopathic effect of powdered and chloroform and aqueous extracts from the root,stem and leaves of Aconi-tum leucostomum at 0.01,0.02,0.05,and 0.10 g/mL on the receptor plants,Festuca elata,Poa pratensis,Elymus nutans and Taraxacum officinale were studied with the culture dish method.Allelochemicals from the root,stem and leaves of A. leucostomum inhibited root and seedling height of receptor plants.The lowest biological activity was observed with the chloroform extract,that of the powder was intermediate,and the aqueous extract was the most active,indicating that water -soluble compounds were the major allelochemicals of A.leucostomum.There was no difference in activity among plant parts of A.leucostomum,implying that its major allelochemicals are distributed throughout the plant.

  18. Avaliação do potencial alelopático de genótipos de aveia no final do ciclo Evaluation of allelopathic potential of oat genotypes at the end of life cycle

    Directory of Open Access Journals (Sweden)

    Ubiratã S. Jacobi

    1998-12-01

    Full Text Available Em sistemas de cultivo em semeadura direta, a aveia é uma das culturas de inverno mais importantes entre as que são utilizadas para formação de cobertura morta. Nos tecidos da aveia existem aleloquímicos, o que torna importante o entendimento deste fenômeno nesta cultura. Através da análise da palha de resíduos de genótipos de aveia, bem como dos seus aleloquímicos, poder-se-á obter uma avaliação ampla do seu potencial alelopático. Nesta análise, pode-se verificar que os genótipos de aveia mantém o potencial alelopático no final do ciclo de vida, revelando-se com maior efeito alelopático UFRGS 6, UFRGS 9, UFRGS 10 e UPF 13. Ao mesmo tempo, os genótipos que exibem menor efeito alelopático são UFRGS 12, UFRGS 17, UFRGS 884077 e UPF 12. Os efeitos produzidos por compostos aleloquímicos (ácidos fenólicos são similares aos provocados pelos extratos dos genótipos de aveia, mostrando uma relação entre o efeito alelopático dessas substâncias e os genótipos testados. Os aleloquímicos apresentam maior fitotoxicidade para as infestantes do que para as culturas, assim como ocorre com os resíduos de genótipos de aveia.In no-till cropping systems, oat represents one of the winter most important crops among those that are used to form cover crops. The presence of allelochemicals in its tissues point to the importance of understanding this phenomenon in the crop. By analyzing the straw of oat genotypes and its allelochemicals, it is possible to obtain a evaluation of its allelopathic potential. Results of this study show that oat genotypes maintain their allelopathic potential during the final period of the life cycle. Genotypes that present greater allelopathic effects during that period are UFRGS 6, UFRGS 9, UFRGS 10, and UPF 13. Genotypes that exhibit least allelopathic effects during the same period are UFRGS 12, UFRGS 17, UFRGS 884077, and UPF 12. The effects produced by allelochemical compounds (phenolic acids are

  19. Allelopathic activity of Nepeta nuda L. subsp. nuda water extracts

    Science.gov (United States)

    Dragoeva, Asya; Stoyanova, Zheni; Koleva, Vanya; Dragolova, Daniela

    2017-03-01

    Nepeta nuda subsp. nuda is a medicinal plant growing wild in Bulgaria. Different species of Nepeta genus have been reported to possess allelopathic potential. The present study was conducted to observe its phytotoxic effects on T. aestivum and C. sativus L. seeds in laboratory conditions. Nepeta water extracts (NWE) prepared from aerial parts of plants at concentrations 2, 4, 6, 8, 10, 12 and 14 g/l were tested. The rate of seed germination, the root and shoot length, fresh and dry weight of seedlings were observed after treatment with NWE. As a control served seeds treated with distilled water. Germination was not affected, but NWE showed deterioration in seedling growth. Roots were more affected than shoots. The fresh and dry weights were reduced upon treatment with the extracts tested. These negative effects were dose-dependent. The overall results indicate presence of water soluble allelochemicals in Nepeta nuda subsp. nuda.

  20. [Regulation effects of grafting on cinnamic acid and vanillin in eggplant root exudates].

    Science.gov (United States)

    Chen, Shao-li; Zhou, Bao-li; Wang, Ru-hua; Fu, Ya-wen

    2008-11-01

    Cinnamic acid and vanillin are the allelochemicals commonly existed in eggplant root exudates. With pot culture experiment, the regulation effects of grafting on the cinnamic acid and vanillin in eggplant root exudates were studied, and the results showed that grafting decreased the amount of the two substances, especially of vanillin, in eggplants root system. The maximum reduction amount of cinnamic acid reached 68.96%, and that of vanillin reached 100%. Under the stress of exotic cinnamic acid and vanillin, especially of exotic cinnamic acid, grafting relieved the autotoxicity of the two substances on eggplants. Compared with own-rooted eggplant, grafted eggplant had a higher plant height and a larger stem diameter, its leaf chlorophyll content increased by 5.26%-13.12%, root electric conductivity and MDA content decreased, and root SOD activity enhanced.

  1. Progress in Understanding Harmful Algal Blooms: Paradigm Shifts and New Technologies for Research, Monitoring, and Management

    Science.gov (United States)

    Anderson, Donald M.; Cembella, Allan D.; Hallegraeff, Gustaaf M.

    2012-01-01

    The public health, tourism, fisheries, and ecosystem impacts from harmful algal blooms (HABs) have all increased over the past few decades. This has led to heightened scientific and regulatory attention, and the development of many new technologies and approaches for research and management. This, in turn, is leading to significant paradigm shifts with regard to, e.g., our interpretation of the phytoplankton species concept (strain variation), the dogma of their apparent cosmopolitanism, the role of bacteria and zooplankton grazing in HABs, and our approaches to investigating the ecological and genetic basis for the production of toxins and allelochemicals. Increasingly, eutrophication and climate change are viewed and managed as multifactorial environmental stressors that will further challenge managers of coastal resources and those responsible for protecting human health. Here we review HAB science with an eye toward new concepts and approaches, emphasizing, where possible, the unexpected yet promising new directions that research has taken in this diverse field.

  2. The Effects of Plant Secondary Compounds on Herbivorous Insects

    Directory of Open Access Journals (Sweden)

    Oğuzhan Yanar

    2017-02-01

    Full Text Available Plants have developed mechanical and chemical defense strategies that are effective against herbivores. Plants contain chemicals that are known as secondary metabolites (allelochemical and these chemicals do not directly involve in organisms’ reproduction and growth, on the other hand, they affect survival, growth and behavior of species. These compounds usually take ecological tasks and plants use these compounds against diseases, parasites, and predators for interspecies competition. It is known through the observations on feeding of herbivorous insects that these compounds act as deterrent chemicals or they are toxic against them. Feeding is one of the most fundamental and the most important behaviors for herbivorous insects. Even though host plant preference of herbivores is partially depend on nutrients, this behavior greatly depends on secondary chemistry of plants. Effects of secondary compounds on herbivorous insects can be positive or negative.

  3. Biochemical activities of berberine, palmatine and sanguinarine mediating chemical defence against microorganisms and herbivores.

    Science.gov (United States)

    Schmeller, T; Latz-Brüning, B; Wink, M

    1997-01-01

    The alkaloids berberine, palmatine and sanguinarine are toxic to insects and vertebrates and inhibit the multiplication of bacteria, fungi and viruses. Biochemical properties which may contribute to these allelochemical activities were analysed. Acetylcholine esterase, butyrylcholinesterase, choline acetyl transferase, alpha 1- and alpha 2-adrenergic, nicotinergic, muscarinergic and serotonin2 receptors were substantially affected. Sanguinarine appears to be the most effective inhibitor of choline acetyl-transferase (IC50 284 nM), while the protoberberines were inactive at this target. Berberine and palmatine were most active at the alpha 2-receptor (binding with IC50 476 and 956 nM, respectively). Furthermore, berberine and sanguinarine intercalate DNA, inhibit DNA synthesis and reverse transcriptase. In addition, sanguinarine (but not berberine) affects membrane permeability and berberine protein biosynthesis. In consequence, these biochemical activities may mediate chemical defence against microorganisms, viruses and herbivores in the plants producing these alkaloids.

  4. Inter-plant communication through mycorrhizal networks mediates complex adaptive behaviour in plant communities.

    Science.gov (United States)

    Gorzelak, Monika A; Asay, Amanda K; Pickles, Brian J; Simard, Suzanne W

    2015-01-01

    Adaptive behaviour of plants, including rapid changes in physiology, gene regulation and defence response, can be altered when linked to neighbouring plants by a mycorrhizal network (MN). Mechanisms underlying the behavioural changes include mycorrhizal fungal colonization by the MN or interplant communication via transfer of nutrients, defence signals or allelochemicals. We focus this review on our new findings in ectomycorrhizal ecosystems, and also review recent advances in arbuscular mycorrhizal systems. We have found that the behavioural changes in ectomycorrhizal plants depend on environmental cues, the identity of the plant neighbour and the characteristics of the MN. The hierarchical integration of this phenomenon with other biological networks at broader scales in forest ecosystems, and the consequences we have observed when it is interrupted, indicate that underground 'tree talk' is a foundational process in the complex adaptive nature of forest ecosystems.

  5. Research and mechanism on plant allelopathy inhibition marine red tide: A reviw%植物化感作用抑制海洋赤潮的研究与机理

    Institute of Scientific and Technical Information of China (English)

    边归国

    2013-01-01

    A fully introduce the terrestrial,freshwater aquatic,large algae and so on various plant allelopathy inhibit 19 species of marine red tide algae method,allelochemicals and inhibition mechanism.Preliminary analysis of the large algae and micro algae mutual inhibition,and plant allelopathy inhibition Marine red tide algae technology was discussed.%较全面地介绍了陆生、淡水水生、大型海藻等各种植物化感作用抑制19种海洋赤潮藻类的方法、化感物质和抑制机理,初步分析了大型海藻和微藻之间的相互抑制作用,并对植物化感作用抑制海洋赤潮藻类技术进行展望.

  6. Allelopathic interactions between the red-tide causative dinoflagellate Prorocentrum donghaiense and the diatom Phaeodactylum tricornutum

    Directory of Open Access Journals (Sweden)

    Zhuoping Cai

    2014-06-01

    Full Text Available The interactions between the red-tide causing dinoflagellate Prorocentrum donghaiense and the marine diatom Phaeodactylum tricornutum were investigated using a co-culture experiment and an enriched culture filtrate experiment. The results showed that when the two microalgae were cultured together with different initial cell densities, the growth of one species was basically suppressed by the other one. In addition, the enriched culture filtrates of one species had generally inhibitory effects on the other one. Our result inferred that P. donghaiense and P. tricornutum would interfere with each other mainly by releasing allelochemicals into the culture medium, and that the degree of allelopathic effects was dependent on the initial cell densities and growth phases. The allelopathic interactions between microalgal species may contribute to the formation and succession of red tides.

  7. Genotoxic effect of Lythrum salicaria extract determined by the mussel micronucleus test.

    Science.gov (United States)

    Eck-Varanka, Bettina; Kováts, Nóra; Hubai, Katalin; Paulovits, Gábor; Ferincz, Árpád; Horváth, Eszter

    2015-12-01

    A wide range of aquatic plants have been proven to release allelochemicals, of them phenolics and tannin are considered rather widely distributed. Tannins, however, have been demonstrated to have genotoxic capacity. In our study genotoxic potential of Lythrum salicaria L. (Purple Loosestrife, family Lythraceae) was assessed by the mussel micronucleus test, using Unio pictorum. In parallel, total and hydrolysable tannin contents were determined. Results clearly show that the extract had a high hydrolysable tannin content and significant mutagenic effect. As L. salicaria has been long used in traditional medicine for chronic diarrhoea, dysentery, leucorrhoea and blood-spitting, genotoxic potential of the plant should be evaluated not only with regard to potential effects in the aquatic ecosystem, but also assessing its safe use as a medicinal herb.

  8. Potential improvement of Lymantria dispar L. management by quercetin

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    Perić-Mataruga Vesna

    2014-01-01

    Full Text Available Lymantria dispar, a polyphagous insect pest, copes with a wide variety of host-specific allelochemicals. Glutathione S-transferases (GST are important for catalyzing detoxification in L. dispar. Larval mortality, GST activity in midgut tissue and mass of L. dispar with different trophic adaptations (originating from two forests with a suitable host, Quercus robur, and an unsuitable host, Robinia pseudoacacia, differed after feeding on quercetin supplemented diets (2% or 5% w/w. Quercetin inhibited GST most potently in oak forest larvae that were less adapted to flavonoids in their diet. The larvicidal effect of quercetin on L. dispar larvae depended on the host-use history. We believe this is important in strategies for sustainable control of insect pests. [Projekat Ministarstva nauke Republike Srbije, br. 173027

  9. Allelopathic activity and chemical constituents of walnut (Juglans regia) leaf litter in walnut-winter vegetable agroforestry system.

    Science.gov (United States)

    Wang, Qian; Xu, Zheng; Hu, Tingxing; Rehman, Hafeez Ur; Chen, Hong; Li, Zhongbin; Ding, Bo; Hu, Hongling

    2014-01-01

    Walnut agroforestry systems have many ecological and economic benefits when intercropped with cool-season species. However, decomposing leaf litter is one of the main sources of allelochemicals in such systems. In this study, lettuce (Lactuca sativa var. angustata) was grown in the soil incorporated with walnut leaf litter to assess its allelopathic activity. Lettuce growth and physiological processes were inhibited by walnut leaf litter, especially during early growth stage (1-2 euphylla period) or with large amount of litter addition. The plants treated by small amount of leaf litter recovered their growth afterwards, while the inhibition for 180 g leaf litter persisted until harvest. Twenty-eight compounds were identified in the leaf litter, and several of them were reported to be phytotoxic, which may be responsible for the stress induced by walnut leaf litter. Thus, for highest economic value of vegetables such as lettuce, excessive incorporation of leaf litter should be discouraged.

  10. Augmented multivariate image analysis applied to quantitative structure-activity relationship modeling of the phytotoxicities of benzoxazinone herbicides and related compounds on problematic weeds.

    Science.gov (United States)

    Freitas, Mirlaine R; Matias, Stella V B G; Macedo, Renato L G; Freitas, Matheus P; Venturin, Nelson

    2013-09-11

    Two of major weeds affecting cereal crops worldwide are Avena fatua L. (wild oat) and Lolium rigidum Gaud. (rigid ryegrass). Thus, development of new herbicides against these weeds is required; in line with this, benzoxazinones, their degradation products, and analogues have been shown to be important allelochemicals and natural herbicides. Despite earlier structure-activity studies demonstrating that hydrophobicity (log P) of aminophenoxazines correlates to phytotoxicity, our findings for a series of benzoxazinone derivatives do not show any relationship between phytotoxicity and log P nor with other two usual molecular descriptors. On the other hand, a quantitative structure-activity relationship (QSAR) analysis based on molecular graphs representing structural shape, atomic sizes, and colors to encode other atomic properties performed very accurately for the prediction of phytotoxicities of these compounds against wild oat and rigid ryegrass. Therefore, these QSAR models can be used to estimate the phytotoxicity of new congeners of benzoxazinone herbicides toward A. fatua L. and L. rigidum Gaud.

  11. Microbial metabolites as eco-friendly agrochemicals for the next millennium.

    Science.gov (United States)

    Saxena, S; Pandey, A K

    2001-05-01

    As a result of the increasing environmental and health-related problems caused by the synthetic agrochemicals currently used, suitable and non-hazardous innovative alternatives are being sought. Antagonism and allelopathy, both in nature and in agro-ecosystems, have attracted these researchers' attention, with the main goal of using these phenomena in the biological control of weeds. This article presents a review on the use and efficacy of microbial secondary metabolites which have potential as natural herbicides, either directly or as templates for bio-rational eco-friendly agrochemicals (allelochemicals). Their merits as alternatives to synthetic chemicals and biological control agents have been highlighted for an holistic approach in integrated pest/weed management.

  12. Electrophysiological responses of Atta sexdens rubropilosa workers to essential oils of eucalyptus and its chemical composition.

    Science.gov (United States)

    Batista-Pereira, Luciane G; Fernandes, João B; da Silva, M Fátima G E; Vieira, Paulo C; Bueno, Odair C; Corrêa, Arlene G

    2006-01-01

    The leaf-cutting ant Atta sexdens rubropilosa Forel, 1908 is the most harmful of the Eucalyptus pests, causing severe losses in wood production through defoliation. Various strategies have been tried and effort spent on the development of methods to control this pest, however no practical and environmentally acceptable one currently exists. In this work the chemical composition of the essential oil of seven Eucalyptus species was identified and the selectivity and sensitivity of antennal receptors of A. sexdens rubropilosa workers to the volatile compounds were determined using the electroantennographic technique (EAG and GC-EAD). Analysis by GC-EAD showed in E. cloesiana and E. maculata, respectively, seventeen and sixteen terpenes that elicited responses in ant workers' antennae, indicating the potential role of the essential oils as allelochemicals that determine the choice of the foraging material.

  13. Semiochemistry of the Scarabaeoidea.

    Science.gov (United States)

    Vuts, József; Imrei, Zoltán; Birkett, Michael A; Pickett, John A; Woodcock, Christine M; Tóth, Miklós

    2014-02-01

    The superfamily Scarabaeoidea comprises a large and diverse monophyletic group. Members share ancestral characteristics, but often exhibit considerable differences in their ecology, physiology, or mating strategies. A large number of species are regarded as pests of crop or amenity plants, while others are beneficial to humans and even may be extremely rare as a result of anthropogenic activities. A significant number of chemical ecology-based studies have been conducted with the Scarabaeoidea in order to characterize semiochemicals influencing their behavior, such as pheromones and plant-derived allelochemicals. These may be used either to control or preserve populations of the beetles, depending upon pest or beneficial status. This paper is a review of the role and identity of the semiochemicals of the Scarabaeoidea, with comments on possible future research and applied opportunities in the field of chemical ecology.

  14. Bioactivity effect of two macrophyte extracts on growth performance of two bloom-forming cyanophytes

    Directory of Open Access Journals (Sweden)

    M.G. Ghobrial

    2015-01-01

    Full Text Available Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have beneficial (positive allelopathy or detrimental (negative allelopathy effects on the target organisms. The current research aims at using selected brackish water adapted submerged aquatic macrophytes allelopathy to combat bloom-forming cyanophytes, in laboratory bioassay experiments. Dry matters of macrophytes were extracted in solvents and the initial cyanophytes inoculum, derived from unialgal culture media, was used. Therefore, aqueous extracts with 50% and 100% acetone and ethanol solvents of two freshwater macrophytes; Potamogeton pectinatus and Ceratophyllum demersum were used to test their growth performance exhibited on two bloom-forming cyanophytes, Microcystis aeruginosa and Oscillatoria tenuis. The results revealed insignificant difference between the overall total average growth performance at treatment with 50% and 100% Ceratophyllum acetone extracts expressed by optical density (OD as well as chlorophyll a (chl a. Results showed, also, stimulation of M. aeruginosa growth. The highest growth increase in 100 μl/100 ml treatment with 50% acetone extract had a percentage rate (R of 94.66. On the contrary, treatment with ethanol extract recorded the highest inhibitory effect, thus in 1.5 μl/100 ml treatment with 50% Ceratophyllum ethanol extract R recorded −87.54, sustaining LC50 value of 1.12 μl/100 ml. The highest stimulating effect in 105 μl/100 ml treatment with 50% Ceratophyllum acetone extracts against O. tenuis was; R, 169.4. The highest inhibition in 1500 μl/100 ml treatment with 50% Ceratophyllum ethanol extracts against O. tenuis was; R −74.32, with LC50 0.830 μl/100 ml. While, the highest inhibition by 50% and 100% Potamogeton acetone or ethanol extracts against M. aeruginosa was

  15. Allelopathic potential of Chrozophora tinctoria on early growth of Barley and Wheat

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    Ali Asghar Aliloo

    2015-02-01

    Full Text Available A laboratory bioassay was conducted to investigate the allelopathic effects of Chrozophora tinctoria on germination and seedling growth of barley and wheat. Aqueous leave extracts of C. tinctoria at 5, 10, 15 and 20 % concentrations were prepared and distilled water was used as a control. Results showed that germination percentage of two species decreased with increasing the extract concentrations; however, wheat germination was relatively resistant to allelochemicals than barley. In contrast to germination behavior, seedling traits showed different responses. The extracts improved seedling dry weights, particularly barley, whereas seedling lengths were inhibited. Roots of both species were more affected than shoots by extracts. The extracts reduced seed reserve mobilization significantly (p≤0.05. It was concluded that the used extract had inhibitory effects on seed germination of the crops; however, at seedling stages the effects were severely reduced.

  16. Allelopathic interactions between the red-tide causative dinoflagellate Prorocentrum donghaiense and the diatom Phaeodactylum tricornutum* This study was supported by the Natural Science Foundation of China-Guangdong Province Joint Key Project (U1133003 Science Technology Planning Project of Guangdong Province (2012B020307009 Open Fund from Key Laboratory of Aquatic Eutrophication Control of Harmful Algal Blooms of Guangdong Higher Education Institutes Open Fund from Key Laboratory of Microbial Resources Collection Preservation Ministry of Agriculture.

    Directory of Open Access Journals (Sweden)

    Zhuoping Cai

    2014-06-01

    Full Text Available The interactions between the red-tide causing dinoflagellate Prorocentrum donghaiense and the marine diatom Phaeodactylum tricornutum were investigated using a co-culture experiment and an enriched culture filtrate experiment. The results showed that when the two microalgae were cultured together with different initial cell densities, the growth of one species was basically suppressed by the other one. In addition, the enriched culture filtrates of one species had generally inhibitory effects on the other one. Our result inferred that P. donghaiense and P. tricornutum would interfere with each other mainly by releasing allelochemicals into the culture medium, and that the degree of allelopathic effects was dependent on the initial cell densities and growth phases. The allelopathic interactions between microalgal species may contribute to the formation and succession of red tides.

  17. Effect of Exotic Toxin on the Nutrition of Woodland Soil%外源毒素对林地土壤养分的影响

    Institute of Scientific and Technical Information of China (English)

    陈龙池; 廖利平; 汪思龙; 黄志群

    2002-01-01

    The effect of vanillin and P-hydroxybenzoic acid on Chinese fir(Cunninghamia lanceolata) woodland soil and Schima superba woodland soil was studied in pot culture experiment.The results showed that contents of nitrogen,potassium and organic matter were lower than the control and their change scope were 21.8%,2.8% and 8.2% respectively.The content of available phosphorus were higher and the change scope was 23.7%.In addition,both changes became more significant with increase of phenolic concentration.These results showed that allelochemicals released by plant may affect content of nutrition in soil,and give rise to nutrition deficiency,and then affect Chinese fir growth.

  18. Current Research Status of Allelopathy

    Directory of Open Access Journals (Sweden)

    AHMAD JUNAEDI

    2006-06-01

    Full Text Available The term of allelopathy refers to chemical interactions (inhibitory or stimulatory between plants, between plants and microorganisms, and between microorganisms. The wealth of information on the processes, procedures, and practices of allelopathy has contributed to understanding this field of science. Recently, researches of allelopathy have been conducted in laboratory, greenhouse, and field with multifaceted standpoint in some concerning area: (i allelochemicals identifications and screening test; (ii ecological and physiological aspects of allelopathy; (iii genetic studies and the possibilities of using plant breeding or genetic manipulation to enhance allelopathic varieties; (iv the use of allelopathic potential in the biological control, including as natural pesticide, of weeds and plant diseases as eco-friendly approach for sustainable agriculture scheme.

  19. Effects of mimosine on Wolbachia in mosquito cells: cell cycle suppression reduces bacterial abundance.

    Science.gov (United States)

    Fallon, Ann M

    2015-10-01

    The plant allelochemical L-mimosine (β-[N-(3-hydroxy-4-pyridone)]-α-aminopropionic acid; leucenol) resembles the nonessential amino acid, tyrosine. Because the obligate intracellular alphaproteobacterium, Wolbachia pipientis, metabolizes amino acids derived from host cells, the effects of mimosine on infected and uninfected mosquito cells were investigated. The EC50 for mimosine was 6-7 μM with Aedes albopictus C7-10 and C/wStr cell lines, and was not influenced by infection status. Mosquito cells responded to concentrations of mimosine substantially lower than those used to synchronize the mammalian cell cycle; at concentrations of 30-35 μM, mimosine reversibly arrested the mosquito cell cycle at the G1/S boundary and inhibited growth of Wolbachia strain wStr. Although lower concentrations of mimosine slightly increased wStr abundance, concentrations that suppressed the cell cycle reduced Wolbachia levels.

  20. Evaluation of allelopathic potential of safflower genotypes (Carthamus tinctorius L.

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    Motamedi Marzieh

    2016-12-01

    Full Text Available Forty safflower genotypes were grown under normal irrigation and drought stress. In the first experiment, the allelopathic potential of shoot residues was evaluated using the sandwich method. Each genotype residue (0.4 g was placed in a sterile Petri dish and two layers of agar were poured on that. Radish seeds were placed on agar medium. The radish seeds were cultivated without safflower residues as the controls. The length of the radicle, hypocotyl, and fresh biomass weight and seed germination percentages were measured. A pot experiment was also done on two genotypes with the highest and two with the lowest allelopathic activity selected after screening genotypes in the first experiment. Before entering the reproductive phase, irrigation treatments (normal irrigation and drought stress were applied. Shoots were harvested, dried, milled and mixed with the topsoil of new pots and then radish seeds were sown. The pots with safflower genotypes were used to evaluate the effect of root residue allelopathy. The shoot length, fresh biomass weight, and germination percentage were measured. Different safflower genotypes showed varied allelopathic potential. The results of the first experiment showed that Egypt and Iran-Khorasan genotypes caused maximum inhibitory responses and Australia and Iran-Kerman genotypes resulted in minimum inhibitory responses on radish seedling growth. Fresh biomass weight had the most sensitivity to safflower residues. The results of the pot experiment were consistent with the results of in vitro experiments. Residues produced under drought stress had more inhibitory effects on the measured traits. Safflower root residue may have a higher level of allelochemicals or different allelochemicals than shoot residue.

  1. BOA detoxification of four summer weeds during germination and seedling growth.

    Science.gov (United States)

    Schulz, Margot; Marocco, Adriano; Tabaglio, Vincenzo

    2012-07-01

    A recent greenhouse study revealed a significant reduction of germination and growth of redroot pigweed (Amaranthus retroflexus) and common purslane (Portulaca oleracea) by rye mulch, whereas velvetleaf (Abutilon theophrasti) and common lambsquarters (Chenopodium album) were not suppressed. Since BOA detoxification by metabolic alteration may influence the relation between the benzoxazinoid content of the soil mulch and weed suppression, we tested the dynamics in BOA detoxification in different plant organs of three and 10-day-old seedlings of four warm season weeds incubated with five BOA concentrations (4, 20, 40, 80, and 200 μmol g(-1) fresh weight). In addition, germination and length of 3-day-old seedlings were measured after exposure to 0, 0.3, 1.5, 3, 6, and 15 μmol BOA. Finally, we tested the influence of the MDR translocator inhibitors verapamil, nifedipine, and the GST inhibitor ethycrynic acid on BOA accumulation and detoxification activity. Due to BOA-detoxification, all weeds were able to grow in environments with low BOA contents. At higher contents, Abutilon theophrasti and Chenopodium album had a better chance to survive because of highly active mechanisms that avoided the uptake of BOA (A. theophrasti) and of efficient detoxification activities in youngest seedlings (C. album). The interpretation of all of the data gave the following sequence of increasing sensitivity: A. theophrasti weeds by rye mulches and their benzoxazinoid contents. Our studies demonstrate for the first time that the detoxification of BOA influences the survival of certain weeds in environments enriched with this allelochemical. Therefore, detoxification processes affect the potential for weed suppression by soil allelochemicals in sustainable weed management.

  2. Interference of allelopathic rice with paddy weeds at the root level.

    Science.gov (United States)

    Yang, X-F; Kong, C-H

    2017-02-20

    Despite increasing knowledge of the involvement of allelopathy in negative interactions among plants, relatively little is known about its action at the root level. This study aims to enhance understanding of interactions of roots between a crop and associated weeds via allelopathy. Based on a series of experiments with window rhizoboxes and root segregation methods, we examined root placement patterns and root interactions between allelopathic rice and major paddy weeds Cyperus difformis, Echinochloa crus-galli, Eclipta prostrata, Leptochloa chinensis and Oryza sativa (weedy rice). Allelopathic rice inhibited growth of paddy weed roots more than shoots regardless of species. Furthermore, allelopathic rice significantly reduced total root length, total root area, maximum root width and maximum root depth of paddy weeds, while the weeds adjusted horizontal and vertical placement of their roots in response to the presence of allelopathic rice. With the exception of O. sativa (weedy rice), root growth of weeds avoided expanding towards allelopathic rice. Compared with root contact, root segregation significantly increased inhibition of E. crus-galli, E. prostrata and L. chinensis through an increase in rice allelochemicals. In particular, their root exudates induced production of rice allelochemicals. However, similar results were not observed in C. difformis and O. sativa (weedy rice) with either root segregation or root exudate application. The results demonstrate that allelopathic rice interferes with paddy weeds by altering root placement patterns and root interactions. This is the first case of a root behavioural strategy in crop-weed allelopathic interaction.

  3. Biochemical warfare on the reef: the role of glutathione transferases in consumer tolerance of dietary prostaglandins.

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    Kristen E Whalen

    Full Text Available BACKGROUND: Despite the profound variation among marine consumers in tolerance for allelochemically-rich foods, few studies have examined the biochemical adaptations underlying diet choice. Here we examine the role of glutathione S-transferases (GSTs in the detoxification of dietary allelochemicals in the digestive gland of the predatory gastropod Cyphoma gibbosum, a generalist consumer of gorgonian corals. Controlled laboratory feeding experiments were used to investigate the influence of gorgonian diet on Cyphoma GST activity and isoform expression. Gorgonian extracts and semi-purified fractions were also screened to identify inhibitors and possible substrates of Cyphoma GSTs. In addition, we investigated the inhibitory properties of prostaglandins (PGs structurally similar to antipredatory PGs found in high concentrations in the Caribbean gorgonian Plexaura homomalla. PRINCIPAL FINDINGS: Cyphoma GST subunit composition was invariant and activity was constitutively high regardless of gorgonian diet. Bioassay-guided fractionation of gorgonian extracts revealed that moderately hydrophobic fractions from all eight gorgonian species examined contained putative GST substrates/inhibitors. LC-MS and NMR spectral analysis of the most inhibitory fraction from P. homomalla subsequently identified prostaglandin A(2 (PGA(2 as the dominant component. A similar screening of commercially available prostaglandins in series A, E, and F revealed that those prostaglandins most abundant in gorgonian tissues (e.g., PGA(2 were also the most potent inhibitors. In vivo estimates of PGA(2 concentration in digestive gland tissues calculated from snail grazing rates revealed that Cyphoma GSTs would be saturated with respect to PGA(2 and operating at or near physiological capacity. SIGNIFICANCE: The high, constitutive activity of Cyphoma GSTs is likely necessitated by the ubiquitous presence of GST substrates and/or inhibitors in this consumer's gorgonian diet. This

  4. Gene expression patterns of the coral Acropora millepora in response to contact with macroalgae

    Science.gov (United States)

    Shearer, T. L.; Rasher, D. B.; Snell, T. W.; Hay, M. E.

    2012-12-01

    Contact with macroalgae often causes coral mortality, but the roles of abrasion versus shading versus allelopathy in these interactions are rarely clear, and effects on gene expression are unknown. Identification of gene expression changes within corals in response to contact with macroalgae can provide insight into the mode of action of allelochemicals, as well as reveal transcriptional strategies of the coral that mitigate damage from this competitive interaction, enabling the coral to survive. Gene expression responses of the coral Acropora millepora after long-term (20 days) direct contact with macroalgae ( Chlorodesmis fastigiata, Dictyota bartayresiana, Galaxaura filamentosa, and Turbinaria conoides) and short-term (1 and 24 h) exposure to C. fastigiata thalli and their hydrophobic extract were assessed. After 20 days of exposure, T. conoides thalli elicited no significant change in visual bleaching or zooxanthellae PSII quantum yield within A. millepora nubbins, but stimulated the greatest alteration in gene expression of all treatments. Chlorodesmis fastigiata, D. bartayresiana, and G. filamentosa caused significant visual bleaching of coral nubbins and reduced the PSII quantum yield of associated zooxanthellae after 20 days, but elicited fewer changes in gene expression relative to T. conoides at day 20. To evaluate initial molecular processes leading to reduction of zooxanthella PSII quantum yield, visual bleaching, and coral death, short-term exposures to C. fastigiata thalli and hydrophobic extracts were conducted; these interactions revealed protein degradation and significant changes in catalytic and metabolic activity within 24 h of contact. These molecular responses are consistent with the hypothesis that allelopathic interactions lead to alteration of signal transduction and an imbalance between reactive oxidant species production and antioxidant capabilities within the coral holobiont. This oxidative imbalance results in rapid protein degradation

  5. [Study on allelopathy effect of pericarp extract of Phellodendron amurense].

    Science.gov (United States)

    Zhang, Zhao; Xia, Tianrui; Tao, Yuehong; Dai, Lingchao; Liu, Yanlu; Zhang, Bengang

    2011-02-01

    Through the study of allelopathy of the pericarp of Phellodendron amurense, the role of self-regeneration barriers was investigated in order to find ways and means for the protection of wild populations of P. amurense. Solution preparation: soaked pericarp of P. amurense in distilled water at 4 degrees C to get solution A, and reflux extraction of pericarp with distilled water at 100 degrees C to get solution B. Both of the solution A and solution B were used in the experiment of seed germination and seedling growth with the seeds of cabbage and wheat. The results showed that 20 g x L(-1) concentration of solution A and solution B inhibited significantly seed germination of cabbage and wheat, while 100 g x L(-1) concentration of solution A even completely inhibited the seed germination of wheat. 20 g x L(-1) concentration of solution A significantly inhibited the cabbage and wheat seedling growth, completely inhibited the root growth of cabbage, while 100 g x L(-1) concentrations of solution A completely inhibited seedling growth of cabbage and wheat. Comparing to solution A, the intensity of solution B are diminished on seed germination and seedling growth. It is concluded that the allelopathy of pericarp of P. amurense is multi-material role in the results, some of allelochemicals are easily degradable when exposed to heat. Overall, the allelopathy of pericarp of P. amurense can affect the seed germination and seedling growth. It is supposed that allelochemicals existed in the pericarp of P. amurense is one of the reason leading to difficulties in self-regeneration of its population.

  6. Myrigalone A inhibits Lepidium sativum seed germination by interference with gibberellin metabolism and apoplastic superoxide production required for embryo extension growth and endosperm rupture.

    Science.gov (United States)

    Oracz, Krystyna; Voegele, Antje; Tarkowská, Danuse; Jacquemoud, Dominique; Turecková, Veronika; Urbanová, Terezie; Strnad, Miroslav; Sliwinska, Elwira; Leubner-Metzger, Gerhard

    2012-01-01

    Myrica gale L. (sweet gale) fruit leachate contains myrigalone A (MyA), a rare C-methylated dihydrochalcone and putative allelochemical, which is known to be a phytotoxin impeding seedling growth. We found that MyA inhibited Lepidium sativum L. seed germination in a dose-dependent manner. MyA did not affect testa rupture, but inhibited endosperm rupture and the transition to subsequent seedling growth. MyA inhibited micropylar endosperm cap (CAP) weakening and the increase in the growth potential of the radical/hypocotyl region (RAD) of the embryo, both being key processes required for endosperm rupture. We compared the contents of abscisic acid (ABA) and gibberellins in the tissues and found that the major bioactive forms of gibberellin in L. sativum seed tissues were GA(4) and GA(6), while GA(8) and GA(13) were abundant inactive metabolites. MyA did not appreciably affect the ABA contents, but severely interfered with gibberellin metabolism and signaling by inhibiting important steps catalyzed by GA3 oxidase, as well as by interfering with the GID1-type gibberellin signaling pathway. The hormonally and developmentally regulated formation of apoplastic superoxide radicals is important for embryo growth. Specific zones within the RAD were associated with accumulation of apoplastic superoxide radicals and endoreduplication indicative of embryo cell extension. MyA negatively affected both of these processes and acted as a scavenger of apoplastic reactive oxygen species. We propose that MyA is an allelochemical with a novel mode of action on seed germination.

  7. 黄瓜种子及其萌发期的化感作用研究%Allelopathy of Cucumber Seed during Germination

    Institute of Scientific and Technical Information of China (English)

    王广印; 韩世栋; 陈碧华; 杨和连

    2012-01-01

    In order to ascertain the allelopathy activity of cucumber seeds during germination,we studied the allelopathy effects of cucumber seeds aqueous extract,cucumber seed germination,cucumber radicle exu-dates,cucumber bud exudates,decomposed cucumber seedlings and seedling aqueous extract by adopting laboratory petri dish seed germination bioassay,using 4 categories of vegetables as receptors. The results indicated that:(l)The cucumber seed aqueous extract had an inhibitory effect on germination of Chinese cabbage, radish, tomato and cucumber seeds which showed the cucumber seed contained a few allelochemicals. (2)After extracted seed interior allelochemicals,the cucumber seed germination had allelopathy inhibitory effect on interplanted Chinese cabbage,radish and tomato seeds germination,and the cucumber radicle and bud exudates had different extent allelopathy inhibitory effect on after cultured Chinese cabbage,radish,tomato and cucumber seeds germination. The germination and growth of all vegetable receptors were inhibited to different extent with the different weight decomposed cucumber seedlings and different concentration seedling aqueous extract. It showed the concentration effect which was germination indexes,response index (RI) and synthesis effect (SE) value of vegetable receptors could decrease along with increasing of the weight of decomposed cucumber seedlings and the concentration of seedling aqueous extract. (3)The experiment of cucumber as receptor showed the allelochemicals of cucumber seeds aqueous extract and cucumber seedling organs had the autotoxicity on cucumber seed germination and growth,in which the autotoxicity of decomposed cucumber seedlings,seedling aqueous extract,cucumber radicle exudates and cucumber bud ex-udates were maximum. The studies suggested that allelochemicals of cucumber seeds aqueous extract,germination periods and seedling organs main inhibited the radicle growth, i. e. the radicle of vegetable receptors was most sensitive

  8. 臭草水浸提液化感作用研究%Laboratory Assessment of the Allelopathic Potential of Aqueous Extracts of Praxelis clematidea

    Institute of Scientific and Technical Information of China (English)

    王真辉; 陈文庆; 杨礼富; 袁坤; 陈秋波

    2011-01-01

    以小白菜(Brassica campestris L ssp.Pekinensis(Lour.)Olsson),萝卜(Raphanus sativus L.),水稻(Oryza sativaa L.),热研2号柱花草(Stylosanthes guianensis cv.Reyan No.2)作为测试植物,研究新鲜假臭草(Praxelis clematidea(Criseb.)King and Robinson)水浸提液对种子发芽,新鲜假臭草和风干假臭草水浸提液对幼苗早期生长的化感效应以及不同生长环境下的假臭草浸提液对萝卜幼苗早期生长的化感作用.结果表明:新鲜假臭草浸提液对4种测试植物的种子发芽都有抑制作用.假臭草叶和完整植株水浸提液的化感作用明显大于其它器官水浸提液化感作用,叶可能是似臭草释放化感物质的主要器官.风干和新鲜假臭草水浸提液在低浓度时抑制所有测试植物幼苗根系生长.在逆境(如干旱和养分胁迫)中,假臭草会释放更多的化感物质,从而导致其化感作用增强.%The allelopathic effect of aqueous extracts of fresh Praxelis(Praxelis clematidea)material on germination and of all extracts from fresh and dry Praxelis material on initial seedling growth were studied on the following crops: Chinese cabbage(Brassica campestris L. ssp. Pekinensis(lour.)Olsson), radish(Raphanus sativus L.), rice (Oryza sativa L.) and Stylosanthes CIAT184(Stylosanthes guianensis cv. Reyan No. 2). Allelopathic effect of extracts of Praxelis in various habitats were also studied. All aqueous extracts from fresh Praxelis inhibited seed germination of all four test species. Leaf and whole plant extracts exhibited greater phytotoxicity than extracts from other plant parts. Leaves might be the parts of Praxelis that mainly released the allelochemicals. Dry matter extracts of Praxelis severely inhibited the root growth of the crop species and there was an indication of a similar trend with extracts of fresh material at lower concentrations. Allelopathic activity of P. clematidea increased under adverse(arid or nutriental stress)conditions under which more

  9. Anatomia e histoquímica das folhas de Senna alata Anatomy and histochemistry of Senna alata leaves

    Directory of Open Access Journals (Sweden)

    I.M.C. Rodrigues

    2009-01-01

    Full Text Available Senna alata é uma espécie daninha frequente em pastagens da região amazônica, cujas folhas apresentam propriedades medicinais. Indivíduos dessa espécie foram cultivados e coletados no Campo Experimental da Embrapa Amazônia Oriental, em Belém-PA, para a realização de análises anatômica e histoquímica das folhas, com a finalidade de fornecer elementos para a taxonomia, identificação microscópica de aleloquímicos e caracterização ecofisiológica da espécie. As folhas apresentaram duas formas de tricomas: tectores e glandulares. Outras características foliares encontradas na espécie foram: lâmina foliar anfiestomática, mesofilo dorsiventral e epiderme abaxial papilosa. Algumas dessas características sugerem um mecanismo de adaptação a ambientes com excesso de calor. As folhas são ricas em cristais de oxalato de cálcio, ao longo de suas nervuras - característica da subfamília Caesalpinioideae. Compostos fenólicos, como flavonoides e antraquinonas, foram encontrados em células epidérmicas, da base de tricomas, e células dispersas no parênquima paliçádico, especialmente nas proximidades da nervura mediana. Este estudo confirmou a presença de conhecidas classes de aleloquímicos em diferentes tipos de células do mesofilo de Senna alata.Senna alata is one of the most frequent weed species in the Amazonian region pastures. Its leaves present medicinal properties. Individuals of this species were cultivated and collected in the Experimental Field of Embrapa Amazônia Oriental, Belém-PA, to carry out anatomical and histochemical analyses to provide taxonomy information, microscopic identification of allelochemicals and ecophysiological characterization of the species. Leaves presented two forms of trichomes: tector and glandular. Other foliar characteristics of the species were: amphistomatic leaf, dorsiventral mesophyll and abaxial epidermis papillose. Some of these suggest an adaptation mechanism to excessive warm

  10. Allelopathic cover crop of rye for integrated weed control in sustainable agroecosystems

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    Vincenzo Tabaglio

    2013-02-01

    Full Text Available The allelopathic potential of rye (Secale cereale L. is mainly due to phytotoxic benzoxazinones, compounds that are produced and accumulated in young tissues to different degrees depending on cultivar and environmental influences. Living rye plants exude low levels of benzoxazinones, while cover crop residues can release from 12 to 20 kg ha–1. This paper summarizes the results obtained from several experiments performed in both controlled and field environments, in which rye was used as a cover crop to control summer weeds in a following maize crop. Significant differences in benzoxazinoid content were detected between rye cultivars. In controlled environments, rye mulches significantly reduced germination of some broadleaf weeds. Germination and seedling growth of Amaranthus retroflexus and Portulaca oleracea were particularly affected by the application of rye mulches, while Chenopodium album was hardly influenced and Abutilon theophrasti was advantaged by the presence of the mulch. With reference to the influence of agronomic factors on the production of benzoxazinoids, nitrogen fertilization increased the content of allelochemicals, although proportionally less than dry matter. The field trial established on no-till maize confirmed the significant weed suppressiveness of rye mulch, both for grass and broadleaf weeds. A significant positive interaction between nitrogen (N fertilization and notillage resulting in the suppression of broadleaf weeds was observed. The different behavior of the weeds in the presence of allelochemicals was explained in terms of differential uptake and translocation capabilities. The four summer weeds tested were able to grow in the presence of low amounts of benzoxazolin-2(3H-one (BOA, between 0.3 and 20 mmol g–1 fresh weight. Although there were considerable differences in their sensitivity to higher BOA concentrations, P. oleracea, A. retroflexus, and Ch. album represented a group of species with a consistent

  11. Impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings.

    Science.gov (United States)

    Huang, Weiwei; Hu, Tingxing; Chen, Hong; Wang, Qian; Hu, Hongling; Tu, Lihua; Jing, Liao

    2013-09-01

    A pot experiment was performed to study the impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings. The experimental design scheme was 0 (CK), 40 (A1), 80 (A2) and 120 g pot(-1) (A3) of E. grandis leaves, and changes in the volatile oil chemical composition during litter decomposition were assessed in the present study. The results showed that C. septentrionale leaf litter inhibited the growth of E. grandis saplings, as determined by the height, basal diameter and chlorophyll content, after 69 d (T1). Five months after transplantation (T2), the height growth rate of the E. grandis saplings increased and then gradually reduced (A1: 40 g pot(-1) > A2: 80 g pot(-1) > A3: 120 g pot(-1) > CK: 0 g pot(-1)). After eleven months (T3), the variations in the height and basal diameter were the same as observed at T2, and the inhibition on leaf, branch, root and stem biomass increased with increasing leaf litter content. Gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile compound composition. The results indicated that the C. septentrionale original leaf litter (S1) contained thirty-one volatile compounds, but the treated leaf litter S2 (which was mixed with soil for eleven months to simultaneously plant E. grandis saplings) only possessed fourteen volatile compounds, releasing many secondary metabolites in the soil during decomposition. Most of the volatile compounds were alcohols, monoterpenoids, sesquiterpenes, alkanes, alkene, esters and ketones. Most of the allelochemicals of C. septentrionale might be released during the initial decomposing process, inhibiting the growth of other plants, whereas some nutrients might be released later, promoting the height growth of plants. In conclusion, decomposing C. septentrionale leaf litter release of many allelochemicals in the soil that significantly inhibit the growth of E. grandis.

  12. Bacterial community composition associated with freshwater algae: species specificity vs. dependency on environmental conditions and source community.

    Science.gov (United States)

    Eigemann, Falk; Hilt, Sabine; Salka, Ivette; Grossart, Hans-Peter

    2013-03-01

    We studied bacterial associations with the green alga Desmodesmus armatus and the diatom Stephanodiscus minutulus under changing environmental conditions and bacterial source communities, to evaluate whether bacteria-algae associations are species-specific or more generalized and determined by external factors. Axenic and xenic algae were incubated in situ with and without allelopathically active macrophytes, and in the laboratory with sterile and nonsterile lake water and an allelochemical, tannic acid (TA). Bacterial community composition (BCC) of algae-associated bacteria was analyzed by denaturing gradient gel electrophoresis (DGGE), nonmetric multidimensional scaling, cluster analyses, and sequencing of DGGE bands. BCC of xenic algal cultures of both species were not significantly affected by changes in their environment or bacterial source community, except in the case of TA additions. Species-specific interactions therefore appear to overrule the effects of environmental conditions and source communities. The BCC of xenic and axenic D. armatus cultures subjected to in situ bacterial colonization, however, had lower similarities (ca. 55%), indicating that bacterial precolonization is a strong factor for bacteria-algae associations irrespective of environmental conditions and source community. Our findings emphasize the ecological importance of species-specific bacteria-algae associations with important repercussions for other processes, such as the remineralization of nutrients, and organic matter dynamics.

  13. Allelopathic Effects of Aqueous Extract of Leaf Stem and Root of Sorghum bicolor on Seed Germination and Seedling Growth of Vigna radiata L.

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    Amir MOOSAVI

    2011-05-01

    Full Text Available Seed germination under field conditions is highly influenced by the presence of other plants. Allelopathy is an important mechanism of plant competition, by producing phytotoxins to the plant environment in order to decline other plants growth. Soil sickness problem in farm lands is also known as an allelopathic effect or even autotoxicity. The toxicity of released allelochemicals by a plant in the environment is attributed to its function of concentration, age and metabolic stage. In this study we investigate the effect (5, 20, 35 and 50 g l-1 of leaf, stem and root water extract of sorghum on seed germination and seedling growth of mung bean. The results of the experiment showed that allelopathic effect of different concentrations was not significant for germination percentage, but germination rate and mean germination time decreased significantly by increasing the concentration of allelopathic extracts; also, there was a clear allelopathic effect of sorghum extract on seedling growth of mung bean. 50 g l-1 sorghum stem extract exhibited the highest inhibitory effect on root and shoot growth of mung bean. Among all parts of sorghum, stem extracts showed the highest allelopatic effect on seedling growth. Root extract showed higher inhibitory effect than leaf extracts.

  14. A Simple Method for the Isolation and Purification of 2,4-Dihydroxy-7-Methoxy-2H-1,4-Benzoxazin-3(4H)-One (DIMBOA) from Maize (Zea mays L.) Seedlings

    Institute of Scientific and Technical Information of China (English)

    LI Jing; LIU Xin-gang; DONG Feng-shou; XU Jun; GUO Li-qun; KONG Zhi-qiang; TIAN Ying-ying; WU Yan-bin; ZHENG Yong-quan

    2013-01-01

    2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), the dominant benzoxazinoid hydroxamic acid in maize (Zea Mays L.), serves as important factors of resistance against insects and microbial diseases, allelochemicals used in competition with other plants. In this paper, a novel and simple method for the isolation and purification of DIMBOA from maize seedlings was developed. Frozen shoots from 7-d-old maize seedlings (1 000×g) were firstly defrosted and then were directly homogenized and extracted with ethyl acetate. The macerate was allowed to stand at room temperature (25±2)°C for 1 h to allow enzymatic release of DIMBOA from DIMBOA-glucoside. Then the ethyl acetate phase was filtered, dried and evaporated to dryness. The resulting light-tan, semicrystalline residue was stored at -20°C for 24 h. Upon recrystallization from acetone-hexane, a relative higher yield (0.58 g) of pure DIMBOA crystals was obtained compared with the yield afforded by Woodward methodology (0.26 g).

  15. Allelopathic interactions between the opportunistic species Ulva prolifera and the native macroalga Gracilaria lichvoides.

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    Dong Xu

    Full Text Available Allelopathy, one type of direct plant competition, can be a potent mechanism through which plant communities are structured. The aim of this study was to determine whether allelopathic interactions occur between the opportunistic green tide-forming species Ulva prolifera and the native macroalga Gracilaria lichvoides, both of which were collected from the coastline of East China sea. In laboratory experiments, the presence of G. lichvoides at 1.25 g wet weight L(-1 significantly inhibited growth and photosynthesis of U. prolifera at concentrations of 1.25, 2.50, and 3.75 g wet weight L(-1 (p0.05. Culture medium experiments further confirmed that some allelochemicals may be released by both of the tested macroalgae, and these could account for the observed physiological inhibition of growth and photosynthesis. Moreover, the native macroalgae G. lichvoides was a stronger competitor than the opportunistic species U. prolifera. Collectively, the results of the present study represent a significant advance in exploring ecological questions about the effects of green tide blooms on the macroalgal community.

  16. Allelopathic Interactions between the Opportunistic Species Ulva prolifera and the Native Macroalga Gracilaria lichvoides

    Science.gov (United States)

    Zhang, Xiaowen; Fan, Xiao; Wang, Yitao; Li, Demao; Wang, Wei; Zhuang, Zhimeng; Ye, Naihao

    2012-01-01

    Allelopathy, one type of direct plant competition, can be a potent mechanism through which plant communities are structured. The aim of this study was to determine whether allelopathic interactions occur between the opportunistic green tide-forming species Ulva prolifera and the native macroalga Gracilaria lichvoides, both of which were collected from the coastline of East China sea. In laboratory experiments, the presence of G. lichvoides at 1.25 g wet weight L−1 significantly inhibited growth and photosynthesis of U. prolifera at concentrations of 1.25, 2.50, and 3.75 g wet weight L−1 (p0.05). Culture medium experiments further confirmed that some allelochemicals may be released by both of the tested macroalgae, and these could account for the observed physiological inhibition of growth and photosynthesis. Moreover, the native macroalgae G. lichvoides was a stronger competitor than the opportunistic species U. prolifera. Collectively, the results of the present study represent a significant advance in exploring ecological questions about the effects of green tide blooms on the macroalgal community. PMID:22496758

  17. Aflatoxin B1: Toxicity, bioactivation and detoxification in the polyphagous caterpillar Trichoplusia ni

    Institute of Scientific and Technical Information of China (English)

    Ren Sen Zeng; Zhimou Wen; Guodong Niu; May R.Berenbaum

    2013-01-01

    Trichoplusia ni caterpillars are polyphagous foliage-feeders and rarely likely to encounter aflatoxin B1 (AFB1),a mycotoxin produced by Aspergillus flavus and A.parasiticus,in their host plants.To determine how T.ni copes with AFB1,we evaluated the toxicity ofAFB1 to T.ni caterpillars at different developmental stages and found that AFB1 tolerance significantly increases with larval development.Diet incorporation of AFB1 at 1μg/g completely inhibited larval growth and pupation of newly hatched larvae,but 3μg/g AFB1 did not have apparent toxic effects on larval growth and pupation of caterpillars that first consume this compound 10 days after hatching.Piperonyl butoxide,a general inhibitor of cytochrome P450 monooxygenases (P450s),reduced the toxicity of AFB1,suggesting that AFB1 is bioactivated in T.ni and this bioactivation is mediated by P450s.Some plant allelochemicals,including flavonoids such as flavones,furanocoumarins such as xanthotoxin and imperatorin,and furanochromones such as visnagin,that induce P450s in other lepidopteran larvae ameliorated AFB1 toxicity,suggesting that P450s are also involved in AFB1 detoxification in T.ni.

  18. Bioassay standardization for the detection of allelopathic compounds and environmental toxicants using lettuce

    Directory of Open Access Journals (Sweden)

    Mateus Salomão Simões

    2013-09-01

    Full Text Available The purpose of this study was to assess different experimental conditions to determine a protocol for bioassays based on seed germination and early seedling growth using lettuce (Lactuca sativa L. cv. Grand Rapids as indicator species. This protocol aims to provide support for the standardization of assays of various chemicals such as allelochemicals and environmental toxicants. The following tests were performed: time of germination, temperature, light, solution volume and Petri dish size. For each test (except for time of germination, the influence of the conditions investigated was determined by the endpoints germination percentage, germination speed index, root length, seedling fresh weight and total dry weight. The results showed that variations in the methods altered the results. It is recommended that bioassays using L. sativa L. cv. Grand Rapids be carried out for a minimum period of four days for assessments of both germination and initial growth and that the experimental conditions include a temperature of 20°C, 90-mm Petri dishes or larger, 0.1 mL cypsela solution, and continuous light or 12-hour photoperiod.

  19. Effects of co-existing microalgae and grazers on the production of hemolytic toxins in Karenia mikimotoi

    Institute of Scientific and Technical Information of China (English)

    YANG Weidong; ZHANG Naisheng; CUI Weimin; XU Yanyan; LI Hongye; LIU Jiesheng

    2011-01-01

    Karenia mikimotoi (Miyake & Kominami ex Oda) Hansen & Moestrup is associated with harmful algal blooms in temperate and subtropical zones of the world.The hemolytic substances produced by K.mikimotoi are thought to cause mortality in fishes and invertebrates.We evaluated the composition of the hemolytic toxin produced by K.mikimotoi cultured in the laboratory using thin-layer chromatography.In addition,we evaluated the effect of co-occuring algae (Prorocentrum donghaiense and Alexandrium tamarense) and the cladoceran grazer Moina mongolica on hemolytic toxin production in K.mikimotoi.The hemolytic toxins from K.mikimotoi were a mixture of 2 liposaccharides and I lipid.Waterbome clues from P.donghaiense and A.tamarense inhibited the growth of K.mikimotoi but increased the production of hemolytic toxins.Conversely,K.mikimotoi strongly inhibited the growth of caged P.donghaiense and A.tamarense.In addition,the ingestion of K.mikimotoi by M.mongolica induced the production of hemolytic toxins in K.mikimotoi.Taken together,our results suggest that the presence of other microalgae and grazers may be as important as environmental factors for controlling the production of hemolytic substances.K.mikimotoi secreted allelochemicals other than unstable fatty acids with hemolytic activity.The production of hemolytic toxins in dinoflagellates was not only dependent on resource availability,but also on the risk of predation.Hemolytic toxins likely play an important role as chemical deterrents secreted by K.mikimotoi.

  20. Tissue-specific expression of glutathione S-transferases induced by 2-tridecanone or quercetin in cotton bollworms, Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    TANG Fang; LIANG Pei; GAO Xiwu

    2005-01-01

    The tissue-specific expression of glutathione S-transferases (GSTs) in the cotton bollworm and the expression level induced by 2-tridecanone and quercetin were examined using the methods of biochemistry and the quantitative PCR. The relative expression level of GST mRNA was unanimous with the GSTs activity conjugaging with 1-chloro-2, 4-dimitro-benzene (CDNB) in fat bodies,midguts, heads and integuments of cotton bollworms. The GSTs activity in fat bodies was the highest, then midguts, heads and integuments in turn, which was in consistent with the relative expression level of GST mRNA. The specific activity of GSTs and the relative expression level of GST mRNA could be significantly induced by 2-tridecanone and quercetin, and after the induction the order of the GSTs activity and the relative expression level of GST mRNA in the above four tissues in cotton bollworms was not different from the control.The induction of GSTs by 2-tridecanone was stronger than by quercetin in all four tissues, which was in accordance with the relative expression level of GST mRNA. It suggested that the increase of GSTs activity induced by plant allelochemicals was associated with the elevated expression of GST mRNA in cotton bollworms.

  1. [Potential allelopathic effects of Piper nigrum, Mangifera indica and Clausena lansium].

    Science.gov (United States)

    Yan, Guijun; Zhu, Chaohua; Luo, Yanping; Yang, Ye; Wei, Jinju

    2006-09-01

    With Piper nigrum, Mangifera indica and Clausena lansium as the donators, this paper studied their potential allelopathic effects on the germination and growth of Zea mays, Glycine max, Cucurbita moschata, Arachis hypogaea, Raphanus sativus, Echinochloa crusgalli, Digitaria sanguinalis and Stylosanthes guianensis. The results showed that the aqueous extracts of these donators could inhibit the germination and growth of Z. mays, G. max, C. moschata, E. crus-galli and D. sanguinalis at high concentration, but stimulate them at low concentration. In rhizosphere soil of P. nigrum and M. indica, the germination and growth of Z. mays L was stimulated, while A. hypogaea was inhibited. The aqueous extracts of the donators were extracted by ethyl acetate and n-butanol, respectively, and the inhibitory activity of both aqueous and n-butanol fractions from P. nigrum and M. indica on Z. mays, R. sativus and S. guianensis was stronger than that of ethyl acetate fraction, indicating that P. nigrum and M. indica contained the allelochemicals with high polarity.

  2. Strategies of chemical anti-predator defences in leaf beetles: is sequestration of plant toxins less costly than de novo synthesis?

    Science.gov (United States)

    Zvereva, Elena L; Zverev, Vitali; Kruglova, Oksana Y; Kozlov, Mikhail V

    2017-01-01

    The evolution of defensive traits is driven both by benefits gained from protection against enemies and by costs of defence production. We tested the hypothesis that specialisation of herbivores on toxic host plants, accompanied by the ability to acquire plant defensive compounds for herbivore defence, is favoured by the lower costs of sequestration compared to de novo synthesis of defensive compounds. We measured physiological costs of chemical defence as a reduction in larval performance in response to repeated removal of secretions (simulating predator attack) and compared these costs between five species synthesising defences de novo and three species sequestering salicylic glucosides (SGs) from their host plants. Experiments simulating low predator pressure revealed no physiological costs in terms of survival, weight and duration of development in any of study species. However, simulation of high predation caused reduction in relative growth rate in Chrysomela lapponica larvae producing autogenous defences more frequently, than in larvae sequestering SGs. Still meta-analysis of combined data showed no overall difference in costs of autogenous and sequestered defences. However, larvae synthesising their defences de novo demonstrated secretion-conserving behaviour, produced smaller amounts of secretions, replenished them at considerably lower rates and employed other types of defences (regurgitation, evasion) more frequently when compared to sequestering larvae. These latter results provide indirect evidence for biosynthetic constraints for amounts of defensive secretions produced de novo, resulting in low defence effectiveness. Lifting these constraints by sequestration may have driven some leaf beetle lineages toward sequestration of plant allelochemicals as the main defensive strategy.

  3. Biotechnological and industrial significance of cyanobacterial secondary metabolites.

    Science.gov (United States)

    Rastogi, Rajesh P; Sinha, Rajeshwar P

    2009-01-01

    Cyanobacteria are considered to be a rich source of novel metabolites of a great importance from a biotechnological and industrial point of view. Some cyanobacterial secondary metabolites (CSMs), exhibit toxic effects on living organisms. A diverse range of these cyanotoxins may have ecological roles as allelochemicals, and could be employed for the commercial development of compounds with applications such as algaecides, herbicides and insecticides. Recently, cyanobacteria have become an attractive source of innovative classes of pharmacologically active compounds showing interesting and exciting biological activities ranging from antibiotics, immunosuppressant, and anticancer, antiviral, antiinflammatory to proteinase-inhibiting agents. A different but not less interesting property of these microorganisms is their capacity of overcoming the toxicity of ultraviolet radiation (UVR) by means of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. These last two compounds are true 'multipurpose' secondary metabolites and considered to be natural photoprotectants. In this sense, they may be biotechnologically exploited by the cosmetic industry. Overall CSMs are striking targets in biotechnology and biomedical research, because of their potential applications in agriculture, industry, and especially in pharmaceuticals.

  4. 外来入侵植物小飞蓬化感作用机理研究的进展%The Progress of Studies on the Allelopathy Mechanism of Alien Invasive Plant Conyza Canadensis ( L. ) Cronq.

    Institute of Scientific and Technical Information of China (English)

    张海燕; 罗鑫; 张敏

    2015-01-01

    入侵植物会损害环境生态系统,影响生物的多样性,给农业生产带来严重的经济损失.目前,虽然入侵植物的化感作用研究较多,但是很多缺乏对化感作用的深入研究.结合国内外入侵植物的研究进展,该研究阐述了小飞蓬的研究现状、化感物质的分离鉴定方法以及入侵机理研究的进展.参24.%Alien invasive plants can damage the ecological environment system,have influence on the biological diversity and bring serious economic losses to the agricultural production. At present,there are many studies on the allelopathic effect of the invasive plants,but lack of deep research on the mechanism of allelopathy. Combined with the research progress of invasive plants at home and abroad,this paper in-troduce research actuality, methods of isolation, identification allelochemicals and the progress in the mechanism research of Conyza Canadensis. 24refs.

  5. Dendroctonus armandi (Curculionidae: Scolytinae) cytochrome P450s display tissue specificity and responses to host terpenoids.

    Science.gov (United States)

    Dai, Lulu; Ma, Mingyuan; Gao, Guanqun; Chen, Hui

    2016-11-01

    Bark beetles oxidize the defensive allelochemicals of their host trees both to detoxify them and convert them into components of their pheromone systems which were catalyzed by cytochrome P450 enzymes (CYPs) and occur in different tissues of the insect. We study P450 genes in the Chinese white pine beetle (Dendroctonus armandi), and some bio-information analysis was done for the full-length deduced amino acid sequences. The tissue specificity of these P450 genes was determined in three tissues (antenna, gut and reproductive organs). Differential expression of the P450 genes was observed between sexes, and within these significant differences exposed to stimuli (α-pinene (1:1 racemic mix), (S)-(-)-α-pinene, (S)-(-)-β-pinene, (+)-3-carene, (±)-limonene and turpentine oil) at 24h. Increased expression of P450 genes suggested that they play a role in the detoxification of monoterpenes released by the host trees. The different transcript accumulation patterns of these bark beetle P450 genes provided insight into ecological interactions of D. armandi with its host pine.

  6. Coat of many colours—DNA reveals polymorphism of mantle patterns and colouration in Caribbean Cyphoma Röding, 1798 (Gastropoda, Ovulidae

    Directory of Open Access Journals (Sweden)

    Bastian T. Reijnen

    2017-03-01

    Full Text Available The iconic gastropod genus Cyphoma is commonly observed in the Caribbean, where it lives in association with various octocorallian hosts. Each species in the genus Cyphoma has a unique, characteristic mantle pattern and colouration, which separates the valid taxa. Because of its abundance and recognisability Cyphoma gibbosum has been used as a model organism in several studies concerning allelochemicals, reef degradation, and physical defence mechanisms. Molecular analyses based on four molecular markers (COI, 16S, H3 and 28S for three Cyphoma species (C. gibbosum, C. mcgintyi, C. signatum and an unidentified black morph, collected from three localities in the Caribbean, show that they represent morphological varieties of a single, genetically homogeneous species. This outcome is in agreement with previous anatomical studies. As a result C. mcgintyi and C. signatum are synonymised with C. gibbosum, which is a key result for future work using C. gibbosum as a model organism. The striking morphological differences in mantle pattern and colouration are hypothesised to be the result of one of three possible scenarios: rapid divergence, supergenes (including balanced polymorphism, or incipient speciation.

  7. Comparative field performance of some agricultural crops under a ca-nopy of Populus deltoides and Ulmus wallichiana

    Institute of Scientific and Technical Information of China (English)

    Tariq Hussian Masoodi; Nasir Ahmad Masoodi; Sajad Ahmad Gangoo; Shah Murtaza Mushtaq; Hillal Ahmad

    2013-01-01

    The performance of maize, beans and sunflower was evalu-ated under a canopy of Populus deltoides and Ulmus wallichiana at Fac-ulty of Agriculture, Wadura. The germination, growth and yield of the three test crops were suppressed under both tree species. The reduction, however, decreased when the cultivation of test crops was continued for three years. The inhibition potential generally is in the order of P. del-toides U. wallichiana for beans. Available soil N, P and K increased under the canopy of the selected tree species. The soils under U. wallichiana were more fertile than those under P. deltoides. Chromatographic investigation of extracts showed that the soils under P. deltoides and U. wallichiana differed in their composition of phenolic acids and phenolic glycocides. Except for caffic acid, all other allelochemicals disappeared and were no longer recovered in soil samples obtained after the second or third year of cultivation. Tree-crop compatibility can be explored in greater detail for improved management of traditional agro-ecosystems in Kashmir to increase the overall productivity of the land.

  8. Phytotoxicity of triterpenes and limonoids from the Rutaceae and Meliaceae. 5α,6β,8α,12α-Tetrahydro-28-norisotoonafolin--a potent phytotoxin from Toona ciliata.

    Science.gov (United States)

    Nebo, Liliane; Varela, Rosa M; Molinillo, José M G; Severino, Vanessa G P; Sarria, André L F; Cazal, Cristiane M; Fernandes, Maria Fátima das Graças; Fernandes, João B; Macías, Francisco A

    2015-01-01

    Limonoids and triterpenes are the largest groups of secondary metabolites and have notable biological activities. Meliaceae and Rutaceae are known for their high diversity of metabolites, including limonoids, and are distinguished from other families due to the frequent occurrence of such compounds. The increased interest in crop protection associated with the diverse bioactivity of these compounds has made these families attractive in the search for new allelopathic compounds. In the study reported here we evaluated the bioactivity profiles of four triterpenes (1-4) and six limonoids (5-10) from Meliaceae and Rutaceae. The compounds were assessed in a wheat coleoptile bioassay and those that had the highest activities were tested on the standard target species Lepidinum sativum (cress), Lactuca sativa (lettuce), Lycopersicon esculentum (tomato) and Allium cepa (onion). Limonoids showed phytotoxic activity and 5α,6β,8α, 12α- tetrahydro-28-norisotoonafolin (10) and gedunin (5) were the most active, with bioactivity levels similar to, and in some cases better than, those of the commercial herbicide Logran. The results indicate that these products could also be allelochemicals involved in the ecological interactions of these plant species.

  9. Benzoxazinoids in root exudates of maize attract Pseudomonas putida to the rhizosphere.

    Science.gov (United States)

    Neal, Andrew L; Ahmad, Shakoor; Gordon-Weeks, Ruth; Ton, Jurriaan

    2012-01-01

    Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs) have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere with plant-beneficial traits. Chromatographic analyses revealed that DIMBOA is the main BX compound in root exudates of maize. In vitro analysis of DIMBOA stability indicated that KT2440 tolerance of DIMBOA is based on metabolism-dependent breakdown of this BX compound. Transcriptome analysis of DIMBOA-exposed P. putida identified increased transcription of genes controlling benzoate catabolism and chemotaxis. Chemotaxis assays confirmed motility of P. putida towards DIMBOA. Moreover, colonisation essays in soil with Green Fluorescent Protein (GFP)-expressing P. putida showed that DIMBOA-producing roots of wild-type maize attract significantly higher numbers of P. putida cells than roots of the DIMBOA-deficient bx1 mutant. Our results demonstrate a central role for DIMBOA as a below-ground semiochemical for recruitment of plant-beneficial rhizobacteria during the relatively young and vulnerable growth stages of maize.

  10. Coevolution between invasive and native plants driven by chemical competition and soil biota.

    Science.gov (United States)

    Lankau, Richard A

    2012-07-10

    Although reciprocal evolutionary responses between interacting species are a driving force behind the diversity of life, pairwise coevolution between plant competitors has received less attention than other species interactions and has been considered relatively less important in explaining ecological patterns. However, the success of species transported across biogeographic boundaries suggests a stronger role for evolutionary relationships in shaping plant interactions. Alliaria petiolata is a Eurasian species that has invaded North American forest understories, where it competes with native understory species in part by producing compounds that directly and indirectly slow the growth of competing species. Here I show that populations of A. petiolata from areas with a greater density of interspecific competitors invest more in a toxic allelochemical under common conditions. Furthermore, populations of a native competitor from areas with highly toxic invaders are more tolerant to competition from the invader, suggesting coevolutionary dynamics between the species. Field reciprocal transplants confirmed that native populations more tolerant to the invader had higher fitness when the invader was common, but these traits came at a cost when the invader was rare. Exotic species are often detrimentally dominant in their new range due to their evolutionary novelty; however, the development of new coevolutionary relationships may act to integrate exotic species into native communities.

  11. Metabolomics in chemical ecology.

    Science.gov (United States)

    Kuhlisch, Constanze; Pohnert, Georg

    2015-07-01

    Chemical ecology elucidates the nature and role of natural products as mediators of organismal interactions. The emerging techniques that can be summarized under the concept of metabolomics provide new opportunities to study such environmentally relevant signaling molecules. Especially comparative tools in metabolomics enable the identification of compounds that are regulated during interaction situations and that might play a role as e.g. pheromones, allelochemicals or in induced and activated defenses. This approach helps overcoming limitations of traditional bioassay-guided structure elucidation approaches. But the power of metabolomics is not limited to the comparison of metabolic profiles of interacting partners. Especially the link to other -omics techniques helps to unravel not only the compounds in question but the entire biosynthetic and genetic re-wiring, required for an ecological response. This review comprehensively highlights successful applications of metabolomics in chemical ecology and discusses existing limitations of these novel techniques. It focuses on recent developments in comparative metabolomics and discusses the use of metabolomics in the systems biology of organismal interactions. It also outlines the potential of large metabolomics initiatives for model organisms in the field of chemical ecology.

  12. 土壤微生物对黄花蒿凋落物或青蒿素的响应%Responses of soil microorganisms to Artemisia annua leaf litter or artemisinin

    Institute of Scientific and Technical Information of China (English)

    李倩; 袁玲; 杨水平; 黄建国

    2015-01-01

    Artemisia annua releases many kinds of allelochemicals into soils via dead plant residues,either by rain leaching or root exudation.Dead leaves of A.annua contribute more than 80% of the total artemisinin that enters soils during the growth period of A.annua.Allelochemicals released by the dead leaves reduce the growth and yields of succeeding and adjacent crops.Soil microbes play roles in nutrient transformation,organic matter recycling,toxicant decomposition,and hormone efflux,and thus,are important for plant growth and development.However,little is known about the effects of these allelochemicals on soil microorganisms.In these experiments,artemisinin and A.annua leaf litter were each added to soil and changes in microbial bio-mass and community structure were evaluated.The growth and reproduction of culturable microorganisms in soils showed wide variations in response to A.annua leaf litter or artemisinin.For example,the number of fungi increased but the numbers of actinomycetes,azotobacteria,nitrobacteria,and nitrite bacteria significantly decreased in soils containing A.annua leaf litter or artemisinin.The results suggested that both leaf litter or artemisinin inhibited organic matter mineralization,nitrogen bio-fixation,mobilization of phosphorus and po-tassium,and nitrification.The soil microbial quotient decreased,while the metabolic quotient increased,after A.annua and artemisinin were added to soils.This result indicated that artemisinin and other allelochemicals in the leaf litter interfered with the metabolism of soil microorganisms.The types and total contents of signa-ture phospholipid fatty acids of microbes such as actinomycetes and protozoa decreased in soils containing leaf litter or artemisinin.The diversity and evenness indices of the microbial community also decreased,suggesting that the soil microbial ecosystem deteriorated as the densities of various microbial groups decreased.Therefore, artemisinin and allelopathic chemicals released from A

  13. Benzoxazinoids in root exudates of maize attract Pseudomonas putida to the rhizosphere.

    Directory of Open Access Journals (Sweden)

    Andrew L Neal

    Full Text Available Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H-one (DIMBOA, are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere with plant-beneficial traits. Chromatographic analyses revealed that DIMBOA is the main BX compound in root exudates of maize. In vitro analysis of DIMBOA stability indicated that KT2440 tolerance of DIMBOA is based on metabolism-dependent breakdown of this BX compound. Transcriptome analysis of DIMBOA-exposed P. putida identified increased transcription of genes controlling benzoate catabolism and chemotaxis. Chemotaxis assays confirmed motility of P. putida towards DIMBOA. Moreover, colonisation essays in soil with Green Fluorescent Protein (GFP-expressing P. putida showed that DIMBOA-producing roots of wild-type maize attract significantly higher numbers of P. putida cells than roots of the DIMBOA-deficient bx1 mutant. Our results demonstrate a central role for DIMBOA as a below-ground semiochemical for recruitment of plant-beneficial rhizobacteria during the relatively young and vulnerable growth stages of maize.

  14. Role of secondary metabolites of wild marigold in suppression of Johnson grass and Sun spurge

    Institute of Scientific and Technical Information of China (English)

    Sehrish; Sadia; Rahmatullah; Qureshi; Shahida; Khalid; Brian; Gagosh; Nayyar; Jin-tun; Zhang

    2015-01-01

    Objective: To analyze the wild marigold [(Tagetes minuta L.)(T. minuta)] leaf extract with respect to phytochemicals and allelopathic activity. Methods: The aqueous extracts of T. minuta leaves at concentrations of 50%, 75% and 100% were prepared. Preliminary phytochemical analysis was carried out and then allelopathic ef ect of T. minuta on root length, shoot length, germination, fresh and dry weight of Johnson grass and Sun spurge was tested on i lter paper and in soil.Results: Qualitative phytochemical analysis showed the presence of alkaloids, tannins, saponins, l avonoides and terpenoids. The higher concentrations proved to be signii cantly ef ective in reducing almost all the parameters of Sun spurge and Johnson grass in i lter paper bioassay. Supplemented with the soil, all concentrations of leaf extract showed reduction in germination, root and shoot growth, fresh and dry weight of Sun spurge; however, 100% concentration signii cantly reduced the germination of Johnson grass. Conclusions: This study suggests that marigold allelochemicals can be used as an integrated weed management for the production of better crop yield.

  15. Allelopathic and bioherbicidal potential of Cladonia verticillaris on the germination and growth of Lactuca sativa.

    Science.gov (United States)

    Tigre, R C; Silva, N H; Santos, M G; Honda, N K; Falcão, E P S; Pereira, E C

    2012-10-01

    Responses to germination and initial growth of Lactuca sativa (lettuce) submitted to organic extracts and purified compounds of Cladonia verticillaris ("salambaia") were analyzed in this work. The experiments were conducted in laboratory conditions using extracts and pure compounds at different concentrations. None of the assays showed any influence on the germination of L. sativa seeds using C. verticillaris extracts; however, modifications in leaf area and seedling hypocotyl and root development occurred. In the growth experiments, seedlings exposed to ether or acetone extract showed diminished hypocotyl growth in detriment to the root stimulus, compared to controls. Increases in extract concentrations led to the formation of abnormal seedlings. To determine the allelochemicals of C. verticillaris, its principal components, fumarprotocetraric and protocetraric acids, were isolated and then analyzed by high performance liquid chromatography (HPLC). When the seedlings were exposed to the two acids separately, presented increased leaf area at all concentrations. In contrast, hypocotyl and root stimulus was observed only in the presence of protocetraric acid at different concentrations. Fumarprotocetraric as well as protocetraric acids, isolated and purified from C. verticillaris and Parmotrema dilatatum respectively, influenced the development of L. sativa seedlings at high concentrations, indicating a possible bioherbicide potential of these acids.

  16. Allelopathic interactions between the opportunistic species Ulva prolifera and the native macroalga Gracilaria lichvoides.

    Science.gov (United States)

    Xu, Dong; Gao, Zhengquan; Zhang, Xiaowen; Fan, Xiao; Wang, Yitao; Li, Demao; Wang, Wei; Zhuang, Zhimeng; Ye, Naihao

    2012-01-01

    Allelopathy, one type of direct plant competition, can be a potent mechanism through which plant communities are structured. The aim of this study was to determine whether allelopathic interactions occur between the opportunistic green tide-forming species Ulva prolifera and the native macroalga Gracilaria lichvoides, both of which were collected from the coastline of East China sea. In laboratory experiments, the presence of G. lichvoides at 1.25 g wet weight L(-1) significantly inhibited growth and photosynthesis of U. prolifera at concentrations of 1.25, 2.50, and 3.75 g wet weight L(-1) (p0.05). Culture medium experiments further confirmed that some allelochemicals may be released by both of the tested macroalgae, and these could account for the observed physiological inhibition of growth and photosynthesis. Moreover, the native macroalgae G. lichvoides was a stronger competitor than the opportunistic species U. prolifera. Collectively, the results of the present study represent a significant advance in exploring ecological questions about the effects of green tide blooms on the macroalgal community.

  17. [Effects of Ulva pertusa and Gracilaria lemaneiformis on growth of Heterosigma akashiwo (Raphidophyceae) in co-culture].

    Science.gov (United States)

    Wang, You; Yu, Zhi-ming; Song, Xiu-xian; Zhang, Shan-dong

    2006-02-01

    We studied the effects of fresh tissue and culture medium filtrate of two species of macroalgae, Ulva pertusa (Chlorophyta) and Gracilaria lemaneiformis (Rhodophyta) on growth of Heterosigma akashiwo (Raphidophyceae) in co-culture. Both U. pertusa and G. lemaneiformis, and especially their fresh tissues, significantly impede the growth of H. akashiwo. Carbonate limitations and the presence of environment bacteria are not necessary for the negative effects of macroalgal on H. akashiwo. The simultaneous nutrient assays show that nitrate and phosphate are almost exhausted in the G. lemaneiformis co-culture system, but remain at acceptable levels in the U. pertusa system, when all cells of H. akashiwo are completely dead. When f/2 medium is supplied daily to G. lemaneiformis culture, the growth of H. akashiwo is greatly inhibited but not completely terminated. Furthermore, different amounts of fresh seaweed tissue, and culture medium filtrate prepared from different macroalgal concentrations are analyzed to determine their effects on the growth of H. akashiwo. The results show a positive correlation between the initial macroalgal concentration and the negative effects they exert on the co-cultured microalgae. Results suggest that the allelopathic effects of U. pertusa may be essential for negative effects on H. akashiwo; however, the combined roles of allelopathy and nutrient competition may be responsible for the negative effect of G. lemaneiformis the release of allelochemicals by U. pertusa.

  18. Strigolactone Analogs as Molecular Probes in Chasing the (SLs) Receptor/s: Design and Synthesis of Fluorescent Labeled Molecules

    Institute of Scientific and Technical Information of China (English)

    Cristina Prandi; Helèna Rosso; Beatrice Lace; Ernesto G. Occhiato; Alberto Oppedisano; Silvia Tabasso; Gabriele Alberto

    2013-01-01

    Originally identified as allelochemicals involved in plant-parasite interactions,more recently,Strigolactones (SLs) have been shown to play multiple key roles in the rhizosphere communication between plants and mycorrhizal fungi.Even more recent is the hormonal role ascribed to SLs which broadens the biological impact of these relatively simple molecules.In spite of the crucial and multifaceted biological role of SLs,there are no data on the receptor(s) which bind(s) such active molecules,neither in the producing plants nor in parasitic weeds or AM fungi.Information about the putative receptor of SLs can be gathered by means of structural,molecular,and genetic approaches.Our contribution on this topic is the design and synthesis of fluorescent labeled SL analogs to be used as probes for the detection in vivo of the receptor(s).Knowledge of the putative receptor structure will boost the research on analogs of the natural substrates as required for agricultural applications.

  19. Allelopathy on bark of downed logs of Chamaecyparis Obtusa sieb. and Zucc. var. formosana (Hayata) Rehder.

    Science.gov (United States)

    Tseng, Mei-Hwei; Lai, Wen-Rong; Hsieh, Chin-Lin; Kuo, Yueh-Hsiung

    2007-06-01

    Chamaecyparis obtusa Sieb. and Zucc. var. formosana (Hayata) Rehder is the dominant species in the temperate forest of Yuanyang Lake Nature Reserve (YYL), Taiwan. Although downed logs of C. obstusa var. formosana occupy only a small percentage of the forest floor area in YYL, they are important regeneration substrates. Seedlings of this species often grow without competition on the new downed logs, and a few broadleaf trees grow with them. We hypothesized that the bark of the newly fallen logs possesses allelopathic potential that provides a habitat especially suitable for seedling establishment. Eight different seeds including those from Lactuca sativa L. (lettuce), Bidens pilosa (an invasive weed), and six species in YYL were planted on the bark of the downed logs in an incubator for germination tests. Two dominant species in the forest of YYL, C. obtusa var. formosana and Rhododendron formosanum, were able to grow normally, but the others, Pieris taiwanensis, Barthea formosana, Chamaecyparis formosensis, Miscanthus transmorrisonensis, lettuce, and B. pilosa were growth inhibited. A bioactivity-guided isolation was designed to isolate allelochemicals from the bark. Salicylic acid, one of the inhibiting substances, was isolated and identified by gas chromatography/mass spectroscopy (GC/MS), proton nuclear magnetic resonance ((1)H NMR), and infrared (IR). Bioassay of salicylic acid confirmed a phytotoxic effect. The results suggest that the dominance of C. obtusa var. formosana seedlings on bark could be partly due to allelopathy.

  20. Autotoxicity and Allelopathy of 3,4-Dihydroxyacetophenone Isolated from Picea schrenkiana Needles

    Directory of Open Access Journals (Sweden)

    Zhao-Hui Li

    2011-10-01

    Full Text Available Bioassay-guided fractionation of the diethyl ether fraction of a water extract of Picea schrenkiana needles led to the isolation of the phenolic compound 3,4-dihydroxy- acetophenone (DHAP. The allelopathic effects of DHAP were evaluated under laboratory conditions on P. schrenkiana, rice (Oryza sativa L., wheat (Triticum aestivum L., radish (Raphanus sativus L., lettuce (Latuca sativa L., cucumber (Cucumis sativus L. and mung bean (Phaseolus radiatus L.. DHAP significantly inhibited seed germination and seedling growth of P. schrenkiana at concentrations of 2.5 mM and 0.5 mM (p < 0.05. Soil analysis revealed that P. schrenkiana forest soils contained exceptionally high DHAP concentrations (mean = 0.51 ± 0.03 mg/g dry soil, sufficient to inhibit natural P. schrenkiana recruitment. DHAP also exhibited strong allelopathic potential. It significantly inhibited wheat and lettuce seed germination at concentrations of 1 mM and 0.5 mM (p < 0.05. The active compound also completely inhibited root growth of the six test species at high concentrations. Our results suggest a dual role of DHAP, both as an allelochemical and as an autotoxicant. The potential for a single plant needle-leached compound to influence both inter- and intra-specific interactions emphasized the complex effects that plant secondary metabolites might have on plant population and community structure.

  1. The Extraction, Isolation and Identiifcation of Exudates from the Roots of Flaveria bidentis

    Institute of Scientific and Technical Information of China (English)

    YANG Xing; ZHANG Li-hui; SHI Cui-ping; SHANG Yan; ZHANG Jin-lin; HAN Jian-min; DONG Jin-gao

    2014-01-01

    Large amounts of Flaveria bidentis’s root culturing solution were obtained by using DFT (deep lfow technique) equipment and these solution which was vacuum concentrated (10, 20 mg mL-1) can have a certain inhibition on Triticum aestivum, Cucumis sativus, Raphanus sativus, Amaranthus retrolfexus, Setaria viridis, Chenopodium album, Echinochloa crusgalli and Chloris virgata. This outcome suggested some active compounds in the root exudates of Flaveria bidentis can inhibit the germination, seedling elongation and root length. The dichloromethane extract of root exudates was identiifcated by GC-MS, and 29 kinds of compounds, including esters, hydrocarbons, ketones, thiazole, amines, etc. were obtained and the phthalate n-octyl ester, phthalate 2-ethylhexyl ester were proved to be allelochemicals. The culturing solution of root exudates was separated through the resin column and silica gel column and a component inhibiting seedling height, root length and fresh weight of wheat was got. There were 6 kinds of organic compounds in this component including dioctyl phthalate, 1,2-phthalate, mono(2-ethylhexyl) ester by GC-MS.

  2. Flavonoids from leaves of Derris urucu: assessment of potential effects on seed germination and development of weeds

    Directory of Open Access Journals (Sweden)

    EWERTON A.S. DA SILVA

    2013-09-01

    Full Text Available In some previous studies, we described the isolation of nine compounds from leaves of Derris urucu, a species found widely in the Amazon rainforest, identified as five stilbenes and four dihydroflavonols. In this work, three of these dihydroflavonols [urucuol A (1, urucuol B (2 and isotirumalin (3] were evaluated to identify their potential as allelochemicals, and we are also reporting the isolation and structural determination of a new flavonoid [5,3′-dihydroxy-4′-methoxy-(7,6:5″,6″-2″,2″-dimethylpyranoflavanone (4]. We investigated the effects of the dihydroflavonols 1-3 on seed germination and radicle and hypocotyl growth of the weed Mimosa pudica, using solutions at 150 mg.L–1. Urucuol B, alone, was the substance with the greatest potential to inhibit seed germination (26%, while isotirumalin showed greater ability to reduce the development of the hypocotyl (25%, but none of the three substances showed the potential to inhibit radicle. When combined in pairs, the substances showed synergism for the development of root and hypocotyl and effects on seed germination that could be attributed to antagonism. When tested separately, the trend has become more intense effects on seed germination, while for the substances tested in pairs, the intensity of the effect was greater on development of weed.

  3. Allelopathy of aqueous leaf extracts from the invasive alien tree Pittosporum undulatum on germination and growth of barnyard grass

    Directory of Open Access Journals (Sweden)

    Fernando Bertol Carpanezzi

    2014-09-01

    Full Text Available Barnyard grass (Echinochloa crusgalli (L. P. Beauv. is a herbicide-resistant weed that brings negative impacts to rice crops and threatens floodplains biodiversity worldwide. This study aimed to investigate allelopathic influences of extracts from Pittosporum undulatum Vent. (cheesewood leaves on barnyard grass. Leachates in concentrations of 20%, 15%, 10%, 5% and 2.5% (w/v, aqueous extracts from powdered leached and non-leached leaves (10%, 7,5%, 5%, 2.5% and 1.25% for both, coumarin solution at 0.6 mM and original Roundup ® in concentration according to the label information were prepared. Petri-dishes germination bioassays, with counting at each 12 hours, allowed to determinate both germinability and germination rate; polyethylene glycol (PEG 6000 solutions were prepared to evaluate osmotic effects. In growth tests, seedlings were exposed for seven days, when root and shoot lengths were measured. Germination was sensitive to extracts from powdered leaves. In regard to growth, roots showed dose-dependent length reduction and necrosis. Inhibitory effects from different aqueous extracts suggest action of both internal and external leaf allelochemicals, raising the possibility of Pittosporum undulatum use for barnyard grass control.

  4. Phytotoxic effects and chemical analysis of leaf extracts from three Phytolaccaceae species in South Korea.

    Science.gov (United States)

    Kim, Yong Ok; Johnson, Jon D; Lee, Eun Ju

    2005-05-01

    We analyzed phenolic compounds and other elements in leaf extracts and compared morphology of three species of the Phytolaccaceae family found in South Korea. To test allelochemical effects of the three Phytolacca species, we also examined seed germination and dry weight of seedlings of Lactuca indica and Sonchus oleraceus treated with leaf extracts. The concentrations of total phenolic compounds were exotic Phytolacca esculenta (3.9 mg/l), native Phytolacca insularis (4.4 mg/l), and exotic Phytolacca americana (10.2 mg/l). There was no significant difference in concentrations between P. esculenta and P. insularis, but the concentration of total phenolics in P. americana was two times higher than either P. esculenta or P. insularis. Analysis of aqueous extracts by HPLC showed seven phenolic compounds (gallic acid, protocatechuic acid, chlorogenic acid, caffeic acid, m-hydroxybenzoic acid, p-coumaric acid, and cinnamic acid). Total phenolics in P. americana were eight to 16 times higher than either P. esculenta or P. insularis, respectively. P. americana inhibited seed germination and dry weight of the two assay species. The phytotoxic effects of the two Phytolacca species were different, despite the fact that P. esculenta and P. insularis had similar levels of total phenolic compounds. We also found that P. americana had invaded Ullung Island, which suggested that P. americana had excellent adaptability to the environment. The three species of Phytolaccaceae in South Korea can be distinguished by their different allelopathic potentials and morphologies.

  5. The Effect of Polyunsaturated Aldehydes on Skeletonema marinoi (Bacillariophyceae: The Involvement of Reactive Oxygen Species and Nitric Oxide

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    Alessandra A. Gallina

    2014-07-01

    Full Text Available Nitric oxide (NO and reactive oxygen species (ROS production was investigated in the marine diatom, Skeletonema marinoi (SM, exposed to 2E,4E/Z-decadienal (DECA, 2E,4E/Z-octadienal (OCTA, 2E,4E/Z-heptadienal (HEPTA and a mix of these last two (MIX. When exposed to polyunsaturated aldehydes (PUA, a decrease of NO was observed, proportional to the PUA concentration (85% of the initial level after 180 min with 66 µM DECA. Only OCTA, HEPTA and MIX induced a parallel increase of ROS, the highest (2.9-times the control with OCTA concentrations twice the EC50 for growth at 24 h (20 μM. The synthesis of carotenoids belonging to the xanthophyll cycle (XC was enhanced during exposure, suggesting their antioxidant activity. Our data provide evidence that specific pathways exist as a reaction to PUA and that they depend upon the PUA used and/or the diatom species. In fact, Phaeodactylum tricornutum (PT produces NO in response to DECA, but not to OCTA. We advance the hypothesis that SM perceives OCTA and HEPTA as intra-population infochemicals (as it produces PUA, while PT (non-PUA producing species perceives them as allelochemicals. The ability to produce and to use PUA as infochemicals may underlie ecological traits of different diatom species and modulate ecological success in natural communities.

  6. A Metabolic Probe-Enabled Strategy Reveals Uptake and Protein Targets of Polyunsaturated Aldehydes in the Diatom Phaeodactylum tricornutum.

    Directory of Open Access Journals (Sweden)

    Stefanie Wolfram

    Full Text Available Diatoms are unicellular algae of crucial importance as they belong to the main primary producers in aquatic ecosystems. Several diatom species produce polyunsaturated aldehydes (PUAs that have been made responsible for chemically mediated interactions in the plankton. PUA-effects include chemical defense by reducing the reproductive success of grazing copepods, allelochemical activity by interfering with the growth of competing phytoplankton and cell to cell signaling. We applied a PUA-derived molecular probe, based on the biologically highly active 2,4-decadienal, with the aim to reveal protein targets of PUAs and affected metabolic pathways. By using fluorescence microscopy, we observed a substantial uptake of the PUA probe into cells of the diatom Phaeodactylum tricornutum in comparison to the uptake of a structurally closely related control probe based on a saturated aldehyde. The specific uptake motivated a chemoproteomic approach to generate a qualitative inventory of proteins covalently targeted by the α,β,γ,δ-unsaturated aldehyde structure element. Activity-based protein profiling revealed selective covalent modification of target proteins by the PUA probe. Analysis of the labeled proteins gave insights into putative affected molecular functions and biological processes such as photosynthesis including ATP generation and catalytic activity in the Calvin cycle or the pentose phosphate pathway. The mechanism of action of PUAs involves covalent reactions with proteins that may result in protein dysfunction and interference of involved pathways.

  7. The effect of polyunsaturated aldehydes on Skeletonema marinoi (Bacillariophyceae): the involvement of reactive oxygen species and nitric oxide.

    Science.gov (United States)

    Gallina, Alessandra A; Brunet, Christophe; Palumbo, Anna; Casotti, Raffaella

    2014-07-14

    Nitric oxide (NO) and reactive oxygen species (ROS) production was investigated in the marine diatom, Skeletonema marinoi (SM), exposed to 2E,4E/Z-decadienal (DECA), 2E,4E/Z-octadienal (OCTA), 2E,4E/Z-heptadienal (HEPTA) and a mix of these last two (MIX). When exposed to polyunsaturated aldehydes (PUA), a decrease of NO was observed, proportional to the PUA concentration (85% of the initial level after 180 min with 66 µM DECA). Only OCTA, HEPTA and MIX induced a parallel increase of ROS, the highest (2.9-times the control) with OCTA concentrations twice the EC50 for growth at 24 h (20 μM). The synthesis of carotenoids belonging to the xanthophyll cycle (XC) was enhanced during exposure, suggesting their antioxidant activity. Our data provide evidence that specific pathways exist as a reaction to PUA and that they depend upon the PUA used and/or the diatom species. In fact, Phaeodactylum tricornutum (PT) produces NO in response to DECA, but not to OCTA. We advance the hypothesis that SM perceives OCTA and HEPTA as intra-population infochemicals (as it produces PUA), while PT (non-PUA producing species) perceives them as allelochemicals. The ability to produce and to use PUA as infochemicals may underlie ecological traits of different diatom species and modulate ecological success in natural communities.

  8. A Metabolic Probe-Enabled Strategy Reveals Uptake and Protein Targets of Polyunsaturated Aldehydes in the Diatom Phaeodactylum tricornutum.

    Science.gov (United States)

    Wolfram, Stefanie; Wielsch, Natalie; Hupfer, Yvonne; Mönch, Bettina; Lu-Walther, Hui-Wen; Heintzmann, Rainer; Werz, Oliver; Svatoš, Aleš; Pohnert, Georg

    2015-01-01

    Diatoms are unicellular algae of crucial importance as they belong to the main primary producers in aquatic ecosystems. Several diatom species produce polyunsaturated aldehydes (PUAs) that have been made responsible for chemically mediated interactions in the plankton. PUA-effects include chemical defense by reducing the reproductive success of grazing copepods, allelochemical activity by interfering with the growth of competing phytoplankton and cell to cell signaling. We applied a PUA-derived molecular probe, based on the biologically highly active 2,4-decadienal, with the aim to reveal protein targets of PUAs and affected metabolic pathways. By using fluorescence microscopy, we observed a substantial uptake of the PUA probe into cells of the diatom Phaeodactylum tricornutum in comparison to the uptake of a structurally closely related control probe based on a saturated aldehyde. The specific uptake motivated a chemoproteomic approach to generate a qualitative inventory of proteins covalently targeted by the α,β,γ,δ-unsaturated aldehyde structure element. Activity-based protein profiling revealed selective covalent modification of target proteins by the PUA probe. Analysis of the labeled proteins gave insights into putative affected molecular functions and biological processes such as photosynthesis including ATP generation and catalytic activity in the Calvin cycle or the pentose phosphate pathway. The mechanism of action of PUAs involves covalent reactions with proteins that may result in protein dysfunction and interference of involved pathways.

  9. Accelerating of Pink Pigment Excretion from Cyanobacterium Oscillatoria by Co-Cultivation with Anabaena

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    DWI SUSILANINGSIH

    2007-03-01

    Full Text Available The freshwater cyanobacterium Oscillatoria BTCC/A 0004 excretes pink pigment containing lipoproteins with molecular weights of about 10 kDa. This pigment has surfactant properties with strong emulsification activity toward several hydrocarbons. This extracellular metabolite was suspected as toxin or allelochemical in their habitat. In this study, I investigated the effect of co-cultivation of Oscillatoria with Anabaena variabilis on the pigment excretion to explore the physiological roles of this pigment in its natural environment. The dead or viable cells and medium of A. variabilis were added into Oscillatoria cultures. Results showed that co-cultivation of free viable cells of A. variabilis enhanced the excretion of pigment without effect on the cell growth. Co-cultivation with viable cells in separated method and dead cells did not influenced the pigment production. The addition of A. variabilis medium was slightly increased the excretion of the pigment. Those results indicated that direct contact with A. variabilis caused Oscillatoria released a certain signaling compound.

  10. Expression Patterns of Glutathione Transferase Gene (GstI in Maize Seedlings Under Juglone-Induced Oxidative Stress

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    Hubert Sytykiewicz

    2011-11-01

    Full Text Available Juglone (5-hydroxy-1,4-naphthoquinone has been identified in organs of many plant species within Juglandaceae family. This secondary metabolite is considered as a highly bioactive substance that functions as direct oxidant stimulating the production of reactive oxygen species (ROS in acceptor plants. Glutathione transferases (GSTs, E.C.2.5.1.18 represent an important group of cytoprotective enzymes participating in detoxification of xenobiotics and limiting oxidative damages of cellular macromolecules. The purpose of this study was to investigate the impact of tested allelochemical on growth and development of maize (Zea mays L. seedlings. Furthermore, the effect of juglone-induced oxidative stress on glutathione transferase (GstI gene expression patterns in maize seedlings was recorded. It was revealed that 4-day juglone treatment significantly stimulated the transcriptional activity of GstI in maize seedlings compared to control plants. By contrast, at the 6th and 8th day of experiments the expression gene responses were slightly lower as compared with non-stressed seedlings. Additionally, the specific gene expression profiles, as well as the inhibition of primary roots and coleoptile elongation were proportional to juglone concentrations. In conclusion, the results provide strong molecular evidence that allelopathic influence of juglone on growth and development of maize seedlings may be relevant with an induction of oxidative stress in acceptor plants.

  11. Optimization of benzoxazinones as natural herbicide models by lipophilicity enhancement.

    Science.gov (United States)

    Macías, Francisco A; Marín, David; Oliveros-Bastidas, Alberto; Molinillo, José M G

    2006-12-13

    Benzoxazinones are plant allelochemicals well-known for their phytotoxic activity and for taking part in the defense strategies of Gramineae, Ranunculaceae, and Scrophulariceae plants. These properties, in addition to the recently optimized methodologies for their large-scale isolation and synthesis, have made some derivatives of natural products, 2,4-dihydroxy-(2H)-1,4-benzoxazin-3-(4H)-one (DIBOA) and its 7-methoxy analogue (DIMBOA), successful templates in the search for natural herbicide models. These new chemicals should be part of integrated methodologies for weed control. In ongoing research about the structure-activity relationships of benzoxazinones and the structural requirements for their phytotoxicity enhancement and after characterization of the optimal structural features, a new generation of chemicals with enhanced lipophilicity was developed. They were tested on selected standard target species and weeds in the search for the optimal aqueous solubility-lipophilicity rate for phytotoxicity. This physical parameter is known to be crucial in modern drug and agrochemical design strategies. The new compounds obtained in this way had interesting phytotoxicity profiles, empowering the phytotoxic effect of the starting benzoxazinone template in some cases. Quantitative structure-activity relationships were obtained by bioactivity-molecular parameters correlations. Because optimal lipophilicity values for phytotoxicity vary with the tested plant, these new derivatives constitute a more selective way to take advantage of benzoxazinone phytotoxic capabilities.

  12. Variable selection based cotton bollworm odor spectroscopic detection

    Science.gov (United States)

    Lü, Chengxu; Gai, Shasha; Luo, Min; Zhao, Bo

    2016-10-01

    Aiming at rapid automatic pest detection based efficient and targeting pesticide application and shooting the trouble of reflectance spectral signal covered and attenuated by the solid plant, the possibility of near infrared spectroscopy (NIRS) detection on cotton bollworm odor is studied. Three cotton bollworm odor samples and 3 blank air gas samples were prepared. Different concentrations of cotton bollworm odor were prepared by mixing the above gas samples, resulting a calibration group of 62 samples and a validation group of 31 samples. Spectral collection system includes light source, optical fiber, sample chamber, spectrometer. Spectra were pretreated by baseline correction, modeled with partial least squares (PLS), and optimized by genetic algorithm (GA) and competitive adaptive reweighted sampling (CARS). Minor counts differences are found among spectra of different cotton bollworm odor concentrations. PLS model of all the variables was built presenting RMSEV of 14 and RV2 of 0.89, its theory basis is insect volatilizes specific odor, including pheromone and allelochemics, which are used for intra-specific and inter-specific communication and could be detected by NIR spectroscopy. 28 sensitive variables are selected by GA, presenting the model performance of RMSEV of 14 and RV2 of 0.90. Comparably, 8 sensitive variables are selected by CARS, presenting the model performance of RMSEV of 13 and RV2 of 0.92. CARS model employs only 1.5% variables presenting smaller error than that of all variable. Odor gas based NIR technique shows the potential for cotton bollworm detection.

  13. Role of secondary metabolites of wild marigold in suppression of Johnson grass and Sun spurge

    Institute of Scientific and Technical Information of China (English)

    Sehrish Sadia; Rahmatullah Qureshi; Shahida Khalid; Brian Gagosh Nayyar; Jin-tun Zhang

    2015-01-01

    To analyze the wild marigold [(Tagetes minuta L.) (T. minuta)] leaf extract with respect to phytochemicals and allelopathic activity. Methods: The aqueous extracts of T. minuta leaves at concentrations of 50%, 75% and 100%were prepared. Preliminary phytochemical analysis was carried out and then allelopathic effect of T. minuta on root length, shoot length, germination, fresh and dry weight of Johnson grass and Sun spurge was tested on filter paper and in soil. Results: Qualitative phytochemical analysis showed the presence of alkaloids, tannins, saponins, flavonoides and terpenoids. The higher concentrations proved to be significantly effective in reducing almost all the parameters of Sun spurge and Johnson grass in filter paper bioassay. Supplemented with the soil, all concentrations of leaf extract showed reduction in germination, root and shoot growth, fresh and dry weight of Sun spurge; however, 100%concentration significantly reduced the germination of Johnson grass. Conclusions: This study suggests that marigold allelochemicals can be used as an integrated weed management for the production of better crop yield.

  14. Effects of tannic acid on trypsin and leucine aminopeptidase activities in gypsy moth larval midgut

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    Mrdaković Marija

    2013-01-01

    Full Text Available The effects of allelochemical stress on genetic variations in the specific activities of gypsy moth digestive enzymes (trypsin and leucine aminopeptidase and relative midgut mass (indirect measure of food consumption, as well as variability in their plasticity, were investigated in fifth instar gypsy moths originating from two populations with different trophic adaptations (oak and locust-tree forests. Thirty-two full-sib families from the Quercus population and twenty-six full-sib families from the Robinia population were reared on an artificial diet with or without supplementation with tannic acid. Between population differences were observed as higher average specific activity of trypsin and relative midgut mass in larvae from the Robinia population. Significant broad-sense heritabilities were observed for the specific activity of trypsin in the control state, and for specific activity of leucine aminopeptidase in a stressful environment. Significantly lower heritability for relative midgut mass was recorded in larvae from the Robinia population reared under stressful conditions. Significant variability of trypsin plasticity in larvae from both populations and significant variability of leucine aminopeptidase plasticity in larvae from the Robinia population point to the potential for the evolution of enzyme adaptive plastic responses to the presence of stressor. Non-significant across-environment genetic correlations do not represent a constraint for the evolution of enzyme plasticity. [Projekat Ministarstva nauke Republike Srbije, br. 173027

  15. Effects of Saffron Corm and Leaf Extracts on Early Growth of Some Plants to Investigate the Possibility of Using Them as Associated Crop

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    Hamid-Reza FALLAHI

    2014-09-01

    Full Text Available Saffron intercropping with other plants needs to preliminary investigations about the possible negative interactions between saffron and associated crop. In this study, allelopathic effects of saffron leaf and corm extracts on germination and seedling growth indices of alfalfa (Medicago sativa, arugula (Eruca sativa and rapeseed (Brassica napus was investigated in six separate experiments based on completely randomized design. Experimental treatments were consisted of different levels of saffron leaf and corm extracts including 0, 0.75, 1.5, 3 and 6%. The maximum germination percentage of all selected crops was obtained at control treatment (on average 92% and then decreased with increasing extracts concentration. So that, the germination percentage of arugula, canola and alfalfa in highest concentration of extracts were 18, 10 and 8% for leaf extract and 72, 68 and 93% for corm extract, respectively. The relatively similar trend was observed about germination rate, root and plumule lengths and dry weights. Therefore, the inhibitory effect of saffron leaf extract was more than corm extract on initial growth indices of studied plants. The lowest inhibitory effect of saffron leaf extract and even relatively high stimulatory effect of corm extract were obtained on alfalfa initial growth criteria. Considering the differences in allelochemicals mode of action and concentrations in laboratory bioassays with natural condition, it is necessary to investigate the effects of saffron residues on growth of selected associated crops in greenhouse and field scales for the final decision.

  16. Phytochemical relationship of Euphorbia helioscopia and Euphorbia pulcherrima with Lactuca sativa.

    Science.gov (United States)

    Rehman, Hafiza Ayesha; Yousaf, Zubaida; Rashid, Madiha; Younas, Afifa; Arif, Ayesha; Afzal, Ismah; Akram, Waheed

    2014-01-01

    Allelopathy is an important phenomenon that modifies the ecosystem. A plant can enhance or reduce the growth of other plant due to the presence of a number of allelochemicals in its different parts. Euphorbia helioscopia and Euphorbia pulcherrima are medicinal plant species. Both these species are collected from wild resources for various purposes. To reduce the pressure on wild population, it is important to bring them into cultivation. Therefore, the allelopathic effects of E. helioscopia and E. pulcherrima on the growth of lettuce seeds were studied. Three different concentrations (2%, 4% and 6%) of five different solvents (methanol, acetone, ethyl acetate, n-hexane and distilled water) were used to estimate the allelopathic potential of the above-mentioned Euphorbia species. Results indicated a non-significant growth inhibitory effect of both plants on lettuce seeds. Different extracts reduced the growth of test plant to some extent but this inhibition was not significant. From the observed results, it was concluded that the studied Euphorbia species, being medicinally important crops, can be introduced as intercrop with other cash crops.

  17. Allelopathy as a potential strategy to improve microalgae cultivation.

    Science.gov (United States)

    Bacellar Mendes, Leonardo Brantes; Vermelho, Alane Beatriz

    2013-10-21

    One of the main obstacles for continuous productivity in microalgae cultivation is the presence of biological contaminants capable of eliminating large numbers of cells in a matter of days or even hours. However, a number of strategies are being used to combat and prevent contamination in microalgae cultivation. These strategies include the use of extreme conditions in the culture media such as high salinity and high pH to create an unfavorable environment for the competitive organisms or predators of the microalgae. Numerous studies have explored the potential of naturally occurring bioactive secondary metabolites, which are natural products from plants and microorganisms, as a source of such compounds. Some of these compounds are herbicides, and marine and freshwater microalgae are a source of these compounds. Microalgae produce a remarkable diversity of biologically active metabolites. Results based on the allelopathic potential of algae have only been described for laboratory-scale production and not for algae cultivation on a pilot scale. The adoption of allelopathy on microalgal strains is an unexplored field and may be a novel solution to improve algae production. Here we present information showing the diversity of allelochemicals from microalgae and the use of an allelopathic approach to control microalgae cultivation on a pilot scale based on R&D activities being carried out in Brazil for biodiesel production.

  18. Autotoxicity and allelopathy of 3,4-dihydroxyacetophenone isolated from Picea schrenkiana needles.

    Science.gov (United States)

    Ruan, Xiao; Li, Zhao-Hui; Wang, Qiang; Pan, Cun-De; Jiang, De-An; Wang, G Geoff

    2011-10-24

    Bioassay-guided fractionation of the diethyl ether fraction of a water extract of Picea schrenkiana needles led to the isolation of the phenolic compound 3,4-dihydroxy- acetophenone (DHAP). The allelopathic effects of DHAP were evaluated under laboratory conditions on P. schrenkiana, rice (Oryza sativa L.), wheat (Triticum aestivum L.), radish (Raphanus sativus L.), lettuce (Latuca sativa L.), cucumber (Cucumis sativus L.) and mung bean (Phaseolus radiatus L.). DHAP significantly inhibited seed germination and seedling growth of P. schrenkiana at concentrations of 2.5 mM and 0.5 mM (p < 0.05). Soil analysis revealed that P. schrenkiana forest soils contained exceptionally high DHAP concentrations (mean = 0.51 ± 0.03 mg/g dry soil), sufficient to inhibit natural P. schrenkiana recruitment. DHAP also exhibited strong allelopathic potential. It significantly inhibited wheat and lettuce seed germination at concentrations of 1 mM and 0.5 mM (p < 0.05). The active compound also completely inhibited root growth of the six test species at high concentrations. Our results suggest a dual role of DHAP, both as an allelochemical and as an autotoxicant. The potential for a single plant needle-leached compound to influence both inter- and intra-specific interactions emphasized the complex effects that plant secondary metabolites might have on plant population and community structure.

  19. Molecular cloning of allelopathy related genes and their relation to HHO in Eupatorium adenophorum.

    Science.gov (United States)

    Guo, Huiming; Pei, Xixiang; Wan, Fanghao; Cheng, Hongmei

    2011-10-01

    In this study, conserved sequence regions of HMGR, DXR, and CHS (encoding 3-hydroxy-3-methylglutaryl-CoA reductase, 1-deoxyxylulose-5-phosphate reductoisomerase and chalcone synthase, respectively) were amplified by reverse transcriptase (RT)-PCR from Eupatorium adenophorum. Quantitative real-time PCR showed that the expression of CHS was related to the level of HHO, an allelochemical isolated from E. adenophorum. Semi-quantitative RT-PCR showed that there was no significant difference in expression of genes among three different tissues, except for CHS. Southern blotting indicated that at least three CHS genes are present in the E. adenophorum genome. A full-length cDNA from CHS genes (named EaCHS1, GenBank ID: FJ913888) was cloned. The 1,455 bp cDNA contained an open reading frame (1,206 bp) encoding a protein of 401 amino acids. Preliminary bioinformatics analysis of EaCHS1 revealed that EaCHS1 was a member of CHS family, the subcellular localization predicted that EaCHS1 was a cytoplasmic protein. To the best of our knowledge, this is the first report of conserved sequences of these genes and of a full-length EaCHS1 gene in E. adenophorum. The results indicated that CHS gene is related to allelopathy of E. adenophorum.

  20. Sources and modes of action of invasive knotweed allelopathy: the effects of leaf litter and trained soil on the germination and growth of native plants

    Directory of Open Access Journals (Sweden)

    Madalin Parepa

    2012-05-01

    Full Text Available Invasive knotweeds, native to Eastern Asia, are among the most dominant plant invaders of European and North American temperate ecosystems. Recent studies indicate that one cause of this dominance might be allelopathy, but the possible sources and modes of action of this allelopathy are insufficiently understood. Here, we asked whether the invasive knotweed Fallopia × bohemica can exert allelopathic effects on native plants also through its leaf litter, or through persistent soil contaminants, and whether these affect the germination or growth of native plants. In a germination experiment with nine native species neither litter leachate, an aqueous extract of knotweed leaves added to the soil, nor trained soil with a history of Fallopia pre-cultivation suppressed the germination or early growth of natives. A mesocosm study with experimental native communities showed that the presence of F. × bohemica, although not a dominant in these communities, caused significant shifts of life-history strategy in two dominant natives, and that similar effects could be elicited through litter leachates or trained soil alone. However, there were hardly any effects on the biomass of natives. Our study indicates that knotweed allelopathy acts on the growth rather than germination of natives, and that soil contamination through persistent allelochemicals may not be a significant problem in habitat restoration. It also shows that allelopathic effects can sometimes be subtle changes in life-history and allocation patterns of the affected species.

  1. Phytotoxicity of leaf aqueous extract of Rapanea umbellata (Mart. Mez (Primulaceae on weeds - doi: 10.4025/actasciagron.v35i2.16166

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    Paula Novaes

    2012-12-01

    Full Text Available Allelopathic substances can be used to develop weed control alternatives based on natural products. The objective of this study was to compare the phytotoxic activity of aqueous leaf extracts of Rapanea umbellata with the toxicity of a synthetic herbicide on the germination and growth of weed species. The weeds species barnyard grass (Echinochloa crus-galli, wild poinsettia (Euphorbia heterophylla and morning glory (Ipomoea grandifolia were used. The effects of the aqueous leaf extract of R. umbellata at concentrations of 10% and 5% (g mL-1 were compared to the control (distilled water and to the synthetic herbicide oxyfluorfen. The average weed germination time was significantly lower (p < 0.05 in control than in extract and herbicide treatments. The herbicide had more significant effects than the extract on the initial growth of the aerial part. However, the initial growth of the root part was significantly more affected by the leaf extract than by the herbicide. The extract also caused many disorders in weed root anatomy. Therefore, the leaf aqueous extract of R. umbellata showed important results that indicate that it should be bioprospected and that its allelochemicals should be purified for the discovery of natural-origin herbicides.

  2. Evidence for an allelopathic interaction between rye and wild oats.

    Science.gov (United States)

    Macías, Francisco A; Oliveros-Bastidas, Alberto; Marín, David; Chinchilla, Nuria; Castellano, Diego; Molinillo, José M G

    2014-10-01

    Allelopathy is a biological phenomenon in which an organism produces one or more biochemicals that influence the growth, survival, and reproduction of other organisms. Allelopathy has been the subject of a great deal of research in chemical ecology since the 1930s. The characterization of the factors that influence this phenomenon has barely been explored, mainly due to the complexity of this area. The main aim of the research carried out to date has been to shed light on the importance of these interactions in agroecosystems, especially in relation to the interactions between crops and weeds. Herein we report the characterization of a complete allelochemical pathway involving benzoxazinones, which are known to participate in allelopathic plant defense interactions of several plants of high agronomic interest. The production of the defense chemicals by a donor plant (crop), the route and transformations of the chemicals released into the environment, and the uptake and phytotoxic effects on a target plant (weed) were all monitored. The results of this study, which is the first of its kind, allowed a complete dynamic characterization of the allelopathic phenomenon for benzoxazinones.

  3. Competition induces allelopathy but suppresses growth and anti-herbivore defence in a chemically rich seaweed.

    Science.gov (United States)

    Rasher, Douglas B; Hay, Mark E

    2014-02-22

    Many seaweeds and terrestrial plants induce chemical defences in response to herbivory, but whether they induce chemical defences against competitors (allelopathy) remains poorly understood. We evaluated whether two tropical seaweeds induce allelopathy in response to competition with a reef-building coral. We also assessed the effects of competition on seaweed growth and seaweed chemical defence against herbivores. Following 8 days of competition with the coral Porites cylindrica, the chemically rich seaweed Galaxaura filamentosa induced increased allelochemicals and became nearly twice as damaging to the coral. However, it also experienced significantly reduced growth and increased palatability to herbivores (because of reduced chemical defences). Under the same conditions, the seaweed Sargassum polycystum did not induce allelopathy and did not experience a change in growth or palatability. This is the first demonstration of induced allelopathy in a seaweed, or of competitors reducing seaweed chemical defences against herbivores. Our results suggest that the chemical ecology of coral-seaweed-herbivore interactions can be complex and nuanced, highlighting the need to incorporate greater ecological complexity into the study of chemical defence.

  4. Microbes as targets and mediators of allelopathy in plants.

    Science.gov (United States)

    Cipollini, Don; Rigsby, Chad M; Barto, E Kathryn

    2012-06-01

    Studies of allelopathy in terrestrial systems have experienced tremendous growth as interest has risen in describing biochemical mechanisms responsible for structuring plant communities, determining agricultural and forest productivity, and explaining invasive behaviors in introduced organisms. While early criticisms of allelopathy involved issues with allelochemical production, stability, and degradation in soils, an understanding of the chemical ecology of soils and its microbial inhabitants has been increasingly incorporated in studies of allelopathy, and recognized as an essential predictor of the outcome of allelopathic interactions between plants. Microbes can mediate interactions in a number of ways with both positive and negative outcomes for surrounding plants and plant communities. In this review, we examine cases where soil microbes are the target of allelopathic plants leading to indirect effects on competing plants, provide examples where microbes play either a protective effect on plants against allelopathic competitors or enhance allelopathic effects, and we provide examples where soil microbial communities have changed through time in response to allelopathic plants with known or potential effects on plant communities. We focus primarily on interactions involving wild plants in natural systems, using case studies of some of the world's most notorious invasive plants, but we also provide selected examples from agriculturally managed systems. Allelopathic interactions between plants cannot be fully understood without considering microbial participants, and we conclude with suggestions for future research.

  5. Functional characterization of wheat ent-kaurene(-like) synthases indicates continuing evolution of labdane-related diterpenoid metabolism in the cereals.

    Science.gov (United States)

    Zhou, Ke; Xu, Meimei; Tiernan, Mollie; Xie, Qian; Toyomasu, Tomonobu; Sugawara, Chizu; Oku, Madoka; Usui, Masami; Mitsuhashi, Wataru; Chono, Makiko; Chandler, Peter M; Peters, Reuben J

    2012-12-01

    Wheat (Triticum aestivum) and rice (Oryza sativa) are two of the most agriculturally important cereal crop plants. Rice is known to produce numerous diterpenoid natural products that serve as phytoalexins and/or allelochemicals. Specifically, these are labdane-related diterpenoids, derived from a characteristic labdadienyl/copalyl diphosphate (CPP), whose biosynthetic relationship to gibberellin biosynthesis is evident from the relevant expanded and functionally diverse family of ent-kaurene synthase-like (KSL) genes found in rice the (OsKSLs). Herein reported is the biochemical characterization of a similarly expansive family of KSL from wheat (the TaKSLs). In particular, beyond ent-kaurene synthases (KS), wheat also contains several biochemically diversified KSLs. These react either with the ent-CPP intermediate common to gibberellin biosynthesis or with the normal stereoisomer of CPP that also is found in wheat (as demonstrated by the accompanying paper describing the wheat CPP synthases). Comparison with a barley (Hordeum vulgare) KS indicates conservation of monocot KS, with early and continued expansion and functional diversification of KSLs in at least the small grain cereals. In addition, some of the TaKSLs that utilize normal CPP also will react with syn-CPP, echoing previous findings with the OsKSL family, with such enzymatic promiscuity/elasticity providing insight into the continuing evolution of diterpenoid metabolism in the cereal crop plant family, as well as more generally, which is discussed here.

  6. Comparison of different cover crop mulches and extracts on inhibition of crop and weed growth

    Directory of Open Access Journals (Sweden)

    Sturm, Domonic Johannes

    2016-02-01

    Full Text Available Weed suppression of cover crops is a result of competition for light, space, water and nutrients and the release of allelochemicals in the soil. Two laboratory and greenhouse experiments were conducted to analyse biochemical effects of extracts and mulches of Fagopyrum tataricum (L. Gaertn., Raphanus sativus var. oleiformis Pers. and a cover crop mixture on germination and plant growth of the crop plants maize (Zea mays L. and sugar beet (Beta vulgaris ssp. vulgaris var. altissima Döll. and the weeds Chenopodium album L., Matricaria chamomilla L. and Stellaria media (L. Vill.. In the first experiment, aqueous cover crop extracts were applied on crop and weed seeds in germination assays. Germination rate, mean germination time and root length of crops and weeds were measured. In experiment 2, the influence of cover crop mulch on germination rate and dry weight of the test plants was determined after a period of 21 days. Significant reductions of the root length for all test plants were observed in experiment 1. Additionally, mean germination time was extended for crops and weeds by all cover crops. Germination rate and dry matter of crops and weeds were decreased significantly in experiment 2 compared to the untreated control. Root length, germination rate and mean germination time in germination tests in experiment 1 were found to be correlated with biomass of crops and weeds in experiment 2. This work reveals the important role of biochemical effects on weed suppression by cover crops.

  7. POTENCIAL FITOTÓXICO DE Pterodon polygalaeflorus BENTH (LEGUMINOSAE SOBRE Acanthospermum australe (LOEFL. O. KUNTZE E Senna occidentalis (L. LINK

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    VALDENIR JOSÉ BELINELO

    2009-01-01

    Full Text Available The objectives of this research were synthesize and characterize the allelopatic activity of 6a,7bdi-hydroxyvouacapan-17b-oic acid derivatives, isolated from seeds of Pterodon polygalaeflorus Benth (Leguminosae. The compound characterization processes involve in infrared spectrometry (IR and hydrogen and carbon nuclear magnetic resonance (1H and 13C NMR including experiments in double dimensions (COSY 1H 1H, HMQC and HMBC. Allellopathic effects were evaluated by bioassays, carried out at controlled 25 °C temperature and photoperiod (12h light/12h dark, during 72 hours. Sample concentrations of 1,0, 100,0 and 1000,0 mg.L-1 were tested. Senna occidentalis (fedegoso and Acanthospermum australe (carrapichinho were used as the target weed plants. Was observed that the allelopatic effect of the compounds increased as a function of the enhancement of concentration, thus showing a relation dose dependence. The N-ethyl-6a-acethoxy- 7b-hydroxyvouacapan-17b-amide and N,N-diethyl-6a-acethoxy-7b-hydroxyvouacapan 17b-amide were the derivatives that present the biggest inhibitory effect on seed germination and root growth of fedegoso and carrapichinho. Therefore, these compounds represent the most allelochemical potential against these weeds.

  8. Bioherbicidal Potential of Leaf-residue of Hyptis suaveolens on the Growth and Physiological Parameters of Parthenium hysterophorus L.

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    Riti Thapar Kapoor

    2011-07-01

    Full Text Available The effects of dry leaf-residues of Hyptis suaveolens L. on the growth and physiological parameters of Parthenium hysterophorus L. was studied in pot culture. Different growth parameters of Parthenium such as size and number of the leaves, height, branches, capitula and seeds/plant were inhibited by leaf residues of H. suaveolens. The amount of chlorophyll and protein was decreased with increased amount of residue. The inhibition in growth parameters of Parthenium hysterophorus was due to decrease in chlorophyll, sugar, protein and lipid contents while organic and amino acids were increased in treatments. The accumulation of organic acid reveals that respiration was hampered in test plant and increase in the amino acids might be the adaptation strategy of Parthenium to avoid environmental stress generated by the allelochemicals present in leaf residues of Hyptis. The decrease in the amount of lipids was proportional to the quantity of dry leaf residues used. The altered physiological parameters result in inhibited growth of Parthenium and the leaf residues of Hyptis suaveolens may be used as potent bioherbicide to control the spread of Parthenium.

  9. [Allelopathy of aqueous extract from Ligularia virgaurea, a dominant weed in psychro-grassland, on pasture plants].

    Science.gov (United States)

    Ma, Ruijun; Wang, Mingli; Zhao, Kun; Guo, Shoujun; Zhao, Qingfang; Sun, Kun

    2006-05-01

    Ligularia virgaurea is a noxious weed widely distributed in the alpine grassland of east Qinghai-Tibet Plateau of China. This paper studied the allelopathy of its aqueous extract on the pasture plants Festuca sinensis, Bromus magnus, Elymus nutans, Poa annua, and F. ovina in the region. The mean response index (RI) values of the pasture plants were calculated, and used to quantitatively assess the allelopathic sensitivity of the receptors at three levels, i. e., growth items, development stages, and species. Corresponding values of the weed were also treated in similar way to assess the allelopathic potential of the donor. The results showed that the allelopathic sensitivity was in the order of P. annua > B. magnus > F. sinensis > F. ovina > E. nutans. Both the seed germination and the seedling growth of test pasture plants were inhibited at species level, suggesting that rain eluviation was one of the means by which the weed released allelochemicals. The aqueous extracts from L. virgaurea root and leaf had a significant inhibitory effect at species level, and the effect of root extract was stronger than that of leaf extract, suggesting the competition among species on the underground resources in natural grassland. Allelopathy played an important role in L. virgaurea invasion, and might be responsible to the formation of mono-dominant community and the degeneration of grassland.

  10. Non-invasive delivery of dsGST is lethal to the sweet potato whitefly, Bemisia tabaci (G.) (Hemiptera: Aleyrodidae).

    Science.gov (United States)

    Asokan, R; Rebijith, K B; Roopa, H K; Kumar, N K Krishna

    2015-02-01

    The sweet potato whitefly, Bemisia tabaci (G.) biotype B (Hemiptera: Aleyrodidae), is one of the most economically important pest, by being a dreaded vector of Geminiviruses, and also causes direct damage to the crops by sucking phloem sap. Glutathione S-transferase (GST) is a large family of multifunctional enzymes that play pivotal roles in the detoxification of secondary allelochemical produced by the host plants and in insecticide resistance, thus regulates insect growth and development. The objective of this study is to show the potential of RNA interference (RNAi) in the management of B. tabaci. RNAi is a sequence-specific gene silencing mechanism induced by double-stranded RNA (dsRNA) which holds tremendous potential in pest management. In this regard, we sequenced the GST from B. tabaci and synthesized approximately 500-bp dsRNA from the above and delivered through diet to B. tabaci. Real-time quantitative PCR (RT-qPCR) showed that continuous application of dsGST at 1.0, 0.5, and 0.25 μg/μl reduced mRNA expression levels for BtGST by 77.43, 64.86, and 52.95 % which resulted in mortality by 77, 59, and 40 %, respectively, after 72 h of application. Disruption of BtGST expression will enable the development of novel strategies in pest management and functional analysis of vital genes in B. tabaci.

  11. Acyl sugars and whitefly (Bemisia tabaci) resistance in segregating populations of tomato genotypes.

    Science.gov (United States)

    Dias, D M; Resende, J T V; Marodin, J C; Matos, R; Lustosa, I F; Resende, N C V

    2016-04-07

    The wild tomato, Solanum pennellii, is an important source of resistance genes against tomato pests. This resistance is due to the presence of acyl sugars (AS), which are allelochemicals that have negative effects on arthropod pests. There are no commercially available tomato cultivars that exhibit significant levels of resistance to arthropod pests. Therefore, this study evaluated resistance to whitefly (Bemisia tabaci) in F2 and F2RC1 tomato genotypes with high AS levels from a cross between Solanum lycopersicum 'Redenção' and the S. pennellii accession, LA-716. Plants were exposed to B. tabaci biotype B at the pre-flowering stage. In both generations, there were significant, negative correlations between AS content and oviposition preference and nymph development. Whitefly exhibited a lower preference for oviposition and produced fewer nymphs in genotypes with high AS levels and the wild parent S. pennellii than in the low AS-level genotypes and Redenção cultivar, demonstrating that the breeding program was effective in transferring resistance to the F2 and F2RC1 generations. RVTA-2010-pl#31 and RVTA-2010-pl#94 in the F2 population are promising genotypes that produced materials with high AS levels in the F2RC1 generation (RVTA-2010-31-pl#177 and RVTA-2010-94-pl#381).

  12. Identification of the toxic compounds produced by Sargassum thunbergii to red tide microalgae

    Institute of Scientific and Technical Information of China (English)

    WANG Renjun; WANG You; TANG Xuexi

    2012-01-01

    The inhibitory effects of methanol extracts from the tissues of three macroalgal species on the growths of three marine red tide microalgae were assessed under laboratory conditions.Extracts of Sargassum thunbergii(Mertens ex Roth)Kuntz tissue had stronger inhibitory effects than those of either Sargassum pallidum(Turner)C.Agardh or Sargassum kjellmanianum Yendo on the growths of Heterosigrna akashiwo(Hada)Hada,Skeletonema costatum(Grey.)Grey,and Prorocentrum micans Ehrenberg.Methanol extracts of S.thunbergii were further divided into petroleum ether,ethyl acetate,butanol,and distilled water phases by liquid-liquid fractionation.The petroleum ether and ethyl acetate fractions had strong algicidal effects on the microalgae.Gas chromatography-mass spectrometry analyses of these two phases identified nine fatty acids,most of which were unsaturated fatty acids.In addition,pure compounds of four of the nine unsaturated fatty acids had effective concentrations below 5 mg/L.Therefore,unsaturated fatty acids are a component of the allelochemicals in S.thunbergii tissue.

  13. Bioefficacy of Alpinia galanga (Zingiberaceae) rhizome extracts, (E)-p-acetoxycinnamyl alcohol, and (E)-p-coumaryl alcohol ethyl ether against Bactrocera dorsalis (Diptera: Tephritidae) and the impact on detoxification enzyme activities.

    Science.gov (United States)

    Sukhirun, N; Pluempanupat, W; Bullangpoti, V; Koul, O

    2011-10-01

    The application of insecticides to control oriental fruit fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae), is a principal component of the current management of these fruit flies. However, we evaluated four extracts of Alpinia galanga Wild Linn (Zingiberaceae) rhizomes against adult flies and found hexane and ethanol extracts to be most effective (LC50 = 4,866 and 6,337 ppm, respectively, after 24 h). This suggested that both nonpolar and polar compounds could be active in the candidate plant. Accordingly, the hexane extract was further processed to isolate nonpolar active compounds from this plant source. Two compounds, (E)-p-acetoxycinnamyl alcohol and (E)-p-coumaryl alcohol ethyl ether, were identified as active ingredients and found to be more active than total hexane extract (LC50 = 3,654 and 4,044 ppm, respectively, after 24 h). The data suggested that the compounds were not synergistic but may have some additive effect in a mixture. The activity of the hexane extract against detoxification enzymes, carboxylesterase (CE) and glutathione transferase (GST) also was determined in vitro. CE was inhibited by 70%, whereas GST was not significantly inhibited. Insect CEs mediate insecticide resistance via their induction; therefore, inhibition of these enzymes by plant allelochemicals could be a useful alternative approach for the management of the pest in the field.

  14. Temporal allocation of metabolic tolerance in the body of beet armyworm in response to three gossypol-cotton cultivars

    Institute of Scientific and Technical Information of China (English)

    Marvin; K; HARRIS

    2009-01-01

    The nutrient composition and enzyme activities in larvae of the beet armyworm, Spodoptera exigua (Hbner), fed on high, medium or low gossypol cotton cultivars were examined at different time intervals. Significantly lower free fatty acid was observed in larvae fed for 6 h on high gossypol ’M9101’ compared to larvae fed on the low (ZMS13) and intermediate (HZ401) gossypol cultivars. Significantly higher trypsin activity was observed in larvae fed on high gossypol ’M9101’ for 24 h compared to those fed for 1, 4 and 6 h. Significantly higher catalase and total superoxide dismutase enzyme activities were observed in larvae of S. exigua fed on high gossypol ’M9101’ compared with low gossypol cultivars ’ZMS13’ and ’HZ401’ for 1, 4, 6 and 24 h. However, significantly lower carboxylesterase and acetylcholinesterase enzyme activities were found in larvae fed on high gossypol ’M9101’ compared with the other cultivars for 1, 4, 6 and 24 h. The interaction between cotton variety and beet armyworm infestation time significantly affected the carboxylesterase enzyme activity in S. exigua. The characterization of the effects of plant allelochemicals on herbivorous larvae is important for aiding understanding of plant-insect interaction as well as in devising solutions to pest problems by breeding plant resistance, identifying metabolic targets for insecticide development, etc.

  15. Natural xenobiotics to prevent cyanobacterial and algal growth in freshwater: contrasting efficacy of tannic acid, gallic acid, and gramine.

    Science.gov (United States)

    Laue, Pauline; Bährs, Hanno; Chakrabarti, Shumon; Steinberg, Christian E W

    2014-06-01

    Allelochemical action against planktonic phototrophs is one central issue in freshwater ecology and quality management. To determine some basic mechanisms of this toxic action, we exposed the coccal green alga, Desmodesmus armatus, and the coccal cyanobacterium, Microcystis aeruginosa, in a batch culture well-supplied with carbon dioxide to increasing concentrations of the polyphenols tannic acid and gallic acid and the alkaloid gramine. The phototrophs were checked after 2d and at the end of the culture for biomass-based growth rates, cell volume, maximum quantum yield of photosystem II (ΦPSIImax), chlorophyll a content (chla) after 2d and at the end of the culture, and lipid peroxidation only at the end of the culture. During the culture, the pH rose from 7.64 to 10.95, a pH characteristic of eutrophic freshwater bodies during nuisance algal blooms. All xenobiotics reduced the growth rate, ΦPSIImax, and chla during the first 2d with M. aeruginosa being more sensitive to the polyphenols than D. armatus. The efficacy of the polyphenols declined with increasing pH, indicating potential polymerization and corresponding reduced bioavailability of the polyphenols. In contrast to the polyphenols, gramine increased its toxic action over time, independent of the prevailing pH. All exposures caused slight to severe lipid peroxidation (LPO) in the phototrophs. Hence, one mechanism of growth inhibition may be oxidative stress-mediated reduction in photosynthesis. The presented results suggest that in successful field trials with leachate, the prevailing environmental conditions may inactivate polyphenols and xenobiotics other than polyphenols may be more effective.

  16. Compartmentalization of oxidative stress and antioxidant defense in the larval gut of Spodoptera littoralis.

    Science.gov (United States)

    Krishnan, Natraj; Sehnal, Frantisek

    2006-09-01

    Allelochemicals play important roles in the plant defense against herbivorous insects. They act as feeding deterrents, interfere with digestion and nutrient absorption, and cause production of potentially dangerous oxidative radicals. This study demonstrates that the distributions of oxidative radicals and of the antioxidant enzymes that eliminate them are compartmentalized in the digestive tract of Spodoptera littoralis larvae. Feeding on diets supplemented with the tannic acid (TA), alpha-solanine, and demissidine, respectively, did not affect the rate of food passage through the digestive tract of larvae but 1.25, 2.5, and 5% TA evoked a strong oxidative response. The amount of the superoxide anion in the foregut tissue and content increased up to 70-fold and the titer of total peroxides in the foregut content about 3-fold. This oxidative stress was associated with enhanced carbonyl content in the foregut tissue proteins, indicative of certain tissue deterioration. Extensive foregut damage was probably prevented by elevated activity of the glutathione S-transferase peroxidase. A complex antioxidant response was elicited in the midgut. The activities of superoxide dismutase and catalase increased significantly in the midgut tissue and content, and the activity of ascorbate peroxidase rose in the midgut tissue. The enzymes apparently eliminated oxidative radicals passing to midgut from the foregut with the food bolus and thereby prevented carbonylation of the midgut proteins. We postulate that the generation of oxidative radicals in the foregut and the induction of antioxidant defense in the midgut are controlled processes and that their compartmentalization is an important functional feature of the digestive tract. The glycoalkaloid alpha-solanine and the aglycone demissidine applied at 0.05 and 0.1% concentrations had no effect on any of the examined parameters.

  17. Toxicity of canavanine in tomato (Solanum lycopersicum L.) roots is due to alterations in RNS, ROS and auxin levels.

    Science.gov (United States)

    Krasuska, Urszula; Andrzejczak, Olga; Staszek, Paweł; Borucki, Wojciech; Gniazdowska, Agnieszka

    2016-06-01

    Canavanine (CAN) is non-proteinogenic aminoacid and a structural analog of arginine (Arg). Naturally, CAN occurs in legumes e.g. jack bean and is considered as a strong allelochemical. As a selective inhibitor of inducible nitric oxide synthase in mammalians, it could act as a modifier of nitric oxide (NO) concentration in plants. Modifications in the content of endogenous reactive nitrogen species (RNS) and reactive oxygen species (ROS) influence root structure and architecture, being also under hormonal control. The aim of the work was to investigate regulation of root growth in tomato (Solanum lycopersicum L. cv. Malinowy Ożarowski) seedling by application of CAN at concentration (10 and 50 μM) leading to 50% or 100% restriction of root elongation. CAN at higher concentration led to slight DNA fragmentation, increased total RNA and protein level. Decline in total respiration rate after CAN supplementation was not associated with enhanced membrane permeability. Malformations in root morphology (shorter and thicker roots, limited number of lateral roots) were accompanied by modification in NO and ONOO(-) localization; determined mainly in peridermal cells and some border cells. Although, CAN resulted in low RNS production, addition of exogenous NO by usage of NO donors did not reverse its negative effect, nor recovery effect was detected after roots imbibition in Arg. To build up a comprehensive view on mode of action of CAN as root growth inhibitor, it was shown an elevated level of auxin. To summarize, we demonstrated several secondary mode of action of CAN, indicating its toxicity in plants linked to restriction in RNS formation accompanied by simultaneous overaccumulation of ROS.

  18. Allelopathic interactions between the macroalga Ulva pertusa and eight microalgal species

    Science.gov (United States)

    Nan, Chunrong; Zhang, Haizhi; Zhao, Guangqiang

    2004-11-01

    Growth of Ulva pertusa and eight microalgal species, Heterosigma akashiwo, Skeletonema costatum, Tetraselmis subcordiformis, Nitzschia closterium, Chaetoceros gracile, Chroomonas placoidea 1967, Isochrysis galbana 8701, and Alexandrium tamarense, was examined in a series of batch, semi-continuous and isolated co-cultures ( U. pertusa and one microalgal species). The results of the experiments with co-cultures confirmed the secretion of allelopathic substances by U. pertusa. Growth was significantly ( p<0.05) suppressed in each of the macroalgal species in batch co-cultures, nutrient replete semi-continuous co-cultures and isolated co-cultures. The percentage growth reduction varied between 42 and 100% in batch co-cultures, between 28 and 100% in semi-continuous co-cultures, and between 21 and 100% in isolated co-cultures. In addition, we examined the potential allelopathic effect of U. pertusa culture filtrate. The Ulva culture filtrate significantly ( p<0.01) inhibited the growth of C. placoidea from 2 days after incubation until the end of the experiment, and it exhibited no inhibitory effect on the growth of the other microalgal species. This may suggest that the allelochemicals released from U. pertusa are rapidly degradable. The microalgae tested exhibited different (stimulatory, inhibitory or no) effects on the growth of U. pertusa. U. pertusa grew faster with H. akashiwo (+16%) and S. costatum (+9%), less with T. subcordiformis (-20%), N. closterium (-23%) and C. gracile (-30%), but was not significantly affected by I. galbana, A. tamarense and C. placoidea. The microalgae tested exhibited no clear allelopathic effects on U. pertusa.

  19. Response of last instar Helicoverpa armigera larvae to Bt toxin ingestion: changes in the development and in the CYP6AE14, CYP6B2 and CYP9A12 gene expression.

    Directory of Open Access Journals (Sweden)

    Pilar Muñoz

    Full Text Available Bt crops are able to produce Cry proteins, which were originally present in Bacillus thuringiensis bacteria. Although Bt maize is very efficient against corn borers, Spanish crops are also attacked by the earworm H. armigera, which is less susceptible to Bt maize. Many mechanisms could be involved in this low susceptibility to the toxin, including the insect's metabolic resistance to toxins due to cytochrome P450 monooxygenases. This paper examines the response of last instar H. armigera larvae to feeding on a diet with Bt and non-Bt maize leaves in larval development and in the gene expression of three P450 cytochromes: CYP6AE14, CYP6B2 and CYP9A12. Larvae fed on sublethal amounts of the Bt toxin showed reduced food ingestion and reduced growth and weight, preventing most of them from achieving the critical weight and pupating; additionally, after feeding for one day on the Bt diet the larvae showed a slight increase in juvenile hormone II in the hemolymp. Larvae fed on the non-Bt diet showed the highest CYP6AE14, CYP6B2 and CYP9A12 expression one day after feeding on the non-Bt diet, and just two days later the expression decreased abruptly, a finding probably related to the developmental programme of the last instar. Moreover, although the response of P450 genes to plant allelochemicals and xenobiotics has been related in general to overexpression in the resistant insect, or induction of the genes when feeding takes place, the expression of the three genes studied was suppressed in the larvae feeding on the Bt toxin. The unexpected inhibitory effect of the Cry1Ab toxin in the P450 genes of H. armigera larvae should be thoroughly studied to determine whether this response is somehow related to the low susceptibility of the species to the Bt toxin.

  20. A link between host plant adaptation and pesticide resistance in the polyphagous spider mite Tetranychus urticae.

    Science.gov (United States)

    Dermauw, Wannes; Wybouw, Nicky; Rombauts, Stephane; Menten, Björn; Vontas, John; Grbic, Miodrag; Clark, Richard M; Feyereisen, René; Van Leeuwen, Thomas

    2013-01-08

    Plants produce a wide range of allelochemicals to defend against herbivore attack, and generalist herbivores have evolved mechanisms to avoid, sequester, or detoxify a broad spectrum of natural defense compounds. Successful arthropod pests have also developed resistance to diverse classes of pesticides and this adaptation is of critical importance to agriculture. To test whether mechanisms to overcome plant defenses predispose the development of pesticide resistance, we examined adaptation of the generalist two-spotted spider mite, Tetranychus urticae, to host plant transfer and pesticides. T. urticae is an extreme polyphagous pest with more than 1,100 documented hosts and has an extraordinary ability to develop pesticide resistance. When mites from a pesticide-susceptible strain propagated on bean were adapted to a challenging host (tomato), transcriptional responses increased over time with ~7.5% of genes differentially expressed after five generations. Whereas many genes with altered expression belonged to known detoxification families (like P450 monooxygenases), new gene families not previously associated with detoxification in other herbivores showed a striking response, including ring-splitting dioxygenase genes acquired by horizontal gene transfer. Strikingly, transcriptional profiles of tomato-adapted mites resembled those of multipesticide-resistant strains, and adaptation to tomato decreased the susceptibility to unrelated pesticide classes. Our findings suggest key roles for both an expanded environmental response gene repertoire and transcriptional regulation in the life history of generalist herbivores. They also support a model whereby selection for the ability to mount a broad response to the diverse defense chemistry of plants predisposes the evolution of pesticide resistance in generalists.

  1. Some Compounds with Pesticide Activity Reported in Recent%新报道的一些具有农药活性的化合物

    Institute of Scientific and Technical Information of China (English)

    张翼翾

    2016-01-01

    在全球的粮食生产中,农药发挥着很大的作用。然而农药应用也带来了一系列问题,如抗性的产生,对环境的影响和人畜的毒害作用,急需人们开发新颖的、安全、低毒农药。以天然物质为农药,或以天然化合物为农药先导物,是目前农药开发的重要途径。介绍了一些具杀线虫活性的天然酯和其类似物,具拒食和杀虫活性的萘酚衍生物以及从刺苞菜蓟分离得到的具有除草活性的物质,具杀螨和杀虫活性的喹啉类似物,具杀菌活性脂肽,除草活性物质holadysenterine和新类别除草活性物质环戊-4-烯-1,3-二酮物。%Pesticides play an important role in world food production. But pesticide application also brings many bad things to us, such as the resistance, pollution to environment, toxicity to human and animals. It is the urgent need to develop novel and safe pesticides with low toxicity. It is a significant tool for developing natural materials as pesticides or taking natural compounds as the lead one. This paper introduced some natural ester compounds and their analogues, naphthol derivatives, cardoon allelochemicals, quinoline analogues,gageopeptides, holadysenterine and a new class of herbicides: cyclopent-4-ene-1,3-diones with different pesticidal activity.

  2. 植物化感作用在控制水华藻类中的应用%Application of Plant Allelopathy in Controlling of Algal Bloom

    Institute of Scientific and Technical Information of China (English)

    邹华; 邓继选; 朱银

    2012-01-01

    伴随着水环境污染,水体中藻类疯长形成的“水华”、“赤潮”现象日益严重.各种化学、物理、生物方法被用于抑制藻类的生长,但这些方法都存在不易控制、成本高、易破坏生态等问题.利用植物化感作用抑制藻类生长具有生态安全和灵敏高效等优点,对湖泊富营养化的生态控制具有非常重要的意义.作者介绍了植物化感抑藻的研究进展,归纳了化感作用的种类和化感物质的化学成分,并讨论了植物化感抑藻的作用机制、抑藻机理,最后对植物化感作用在抑藻方面的研究前景进行了展望.%With the serious water pollution, the "algal bloom", "red tide" formed by the overpopulation of algal is getting worse. At present, different methods including chemical, physical, biological were used to inhibit the growth of algae in polluted water. However, the characteristics of these methods are difficult controlling, high cost, and damaging the ecology. In order to develop a low cost and ecologically safe method to inhibit the growth of algae, plant allelopathy is introduced. In this review, the research progress of algal -inhibition with plant allelopathy was introduced, the types of plant allelopathy and the chemical composition of allelo-chemicals were summarized , the mechanisms and perspective of plant allelopathy were discussed.

  3. Abundance of volatile organic compounds in white ash phloem and emerald ash borer larval frass does not attract Tetrastichus planipennisi in a Y-tube olfactometer.

    Science.gov (United States)

    Chen, Yigen; Ulyshen, Michael D; Poland, Therese M

    2016-10-01

    Many natural enemies employ plant- and/or herbivore-derived signals for host/prey location. The larval parasitoid Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) is 1 of 3 biocontrol agents currently being released in an effort to control the emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coloeptera: Burprestidae) in North America. To enhance its efficiency, allelochemicals that attract it need to be assessed. In this study, ash phloem volatile organic compounds (VOCs) of black, green, and white ash, and EAB larval frass were compared. Foraging behavior of T. planipennisi females in response to VOCs of white ash or frass from EAB larvae feeding on white ash phloem was tested using a Y-tube olfactometer. Results indicated that the 3 ash species had similar VOC profiles. EAB larval frass generally contained greater levels of VOCs than phloem. Factor analysis indicated that the 11 VOCs could be broadly divided into 2 groups, with α-bisabolol, β-caryophyllene, (E)-2-hexenal, (Z)-3-hexenal, limonene, methyl benzoate, methyl indole-3-acetic acid, methyl jasmonate, methyl salicylate as the first group and the rest (i.e., methyl linoleate and methyl linolenate) as a second. Abundance of VOCs in white ash phloem tissue and frass, nevertheless, did not attract T. planipennisi females. The concealed feeding of EAB larvae might explain the selection for detectable and reliable virbrational signals, instead of undetectable and relatively unreliable VOC cues from phloem and frass, in short-range foraging by T. planipennisi. Alternatively, it is possible that T. planipennisi is not amenable to the Y-tube olfactometer assay employed.

  4. Comparative Studies of Substrate and Inhibitor Specificity of Glutathione S-Transferases in Six Tissues of Oxya chinensis (Thunberg) (Orthoptera: Acrididae)

    Institute of Scientific and Technical Information of China (English)

    WU Hai-hua; ZHU Kun-yan; GUO Ya-ping; ZHANG Xiao-min; MA En-bo

    2008-01-01

    Specific activity, substrate specificity, and kinetic parameters (Km and Vmax) of glutathione S-transferases (GSTs) towards three substrates, 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), and p-nitrobenzene chloride (pNBC) were investigated in six tissues (foregut, midgut, hindgut, fat body, hemolymph, and muscle) of Oxya chinensis. In addition, the inhibition in vitro (ethacrynic acid, and Cibacron Blue 3GA) of Oxya chinensis in the six tissues was also investigated. Glutathione S-transferase activity was detected in all the six tissues examined. The rank order of GST activities towards CDNB was fat body > midgut > hindgut > muscle > foregut > hemolymph both in females and males. Glutathione 5-transferase activities in the fat body in females and males were 1.3- to 10.4-fold and 1.1- to 10.0-fold higher than those in the other tissues. The rank order of GST activities towards the other substrates changed slightly. From these results, it was inferred that GSTs in the fat body and midgut played important roles in detoxifying xenobiotics including insecticides and plant allelochemicals in O. chinensis. In the three substrates examined, CDNB seemed to be the best substrate, followed by pNBC and DCNB. The kinetic parameters of GSTs were different among the six tissues. This suggested that GSTs in different tissues have various affinities and catalytic efficiency to substrates. In vitro inhibition study showed that the median inhibition concentration (IC50) values of the two inhibitors to GSTs from the six tissues were different. The results suggested that the two inhibitors have different inhibition potency to GSTs from the different tissues. The observed changes in kinetic parameters and inhibition in vitro among the six tissues of the insect might suggest that the number and structure of isoenzymes and their rate of expression varied for the different tissues.

  5. Biochar reduces copper toxicity in Chenopodium quinoa Willd. In a sandy soil.

    Science.gov (United States)

    Buss, Wolfram; Kammann, Claudia; Koyro, Hans-Werner

    2012-01-01

    Mining, smelting, land applications of sewage sludge, the use of fungicides containing copper (Cu), and other human activities have led to widespread soil enrichment and contamination with Cu and potentially toxic conditions. Biochar (BC) can adsorb several substances, ranging from herbicides to plant-inhibiting allelochemicals. However, the range of potential beneficial effects on early-stage plant growth with regard to heavy metal toxicity is largely unexplored. We investigated the ameliorating properties of a forestry-residue BC under Cu toxicity conditions on early plant growth. Young quinoa plants () were grown in the greenhouse in the presence of 0, 2, and 4% BC application (w/w) added to a sandy soil with 0, 50, or 200 μg g Cu supplied. The plants without BC showed severe stress symptoms and reduced growth shortly after Cu application of 50 μg g and died at 200 μg Cu g. Increasing BC concentrations in the growth medium significantly increased the plant performance without Cu toxicity or under Cu stress. At the 4% BC application rate, the plants with 200 μg g Cu almost reached the same biomass as in the control treatment. In the presence of BC, less Cu entered the plant tissues, which had reduced Cu concentrations in the order roots, shoots, leaves. The amelioration effect also was reflected in the plant-soil system CO gas exchange, which showed clear signs of improvement with BC presence. The most likely ameliorating mechanisms were adsorption of Cu to negatively charged BC surfaces and an improvement of the water supply. Overall, BC seems to be a beneficial amendment with the potential to ameliorate Cu toxicity in sandy soils. Further research with a broad spectrum of different soil types, BCs, and crop plants is required.

  6. The ethnobotany of psychoactive plant use: a phylogenetic perspective

    Directory of Open Access Journals (Sweden)

    Nashmiah Aid Alrashedy

    2016-10-01

    Full Text Available Psychoactive plants contain chemicals that presumably evolved as allelochemicals but target certain neuronal receptors when consumed by humans, altering perception, emotion and cognition. These plants have been used since ancient times as medicines and in the context of religious rituals for their various psychoactive effects (e.g., as hallucinogens, stimulants, sedatives. The ubiquity of psychoactive plants in various cultures motivates investigation of the commonalities among these plants, in which a phylogenetic framework may be insightful. A phylogeny of culturally diverse psychoactive plant taxa was constructed with their psychotropic effects and affected neurotransmitter systems mapped on the phylogeny. The phylogenetic distribution shows multiple evolutionary origins of psychoactive families. The plant families Myristicaceae (e.g., nutmeg, Papaveraceae (opium poppy, Cactaceae (peyote, Convolvulaceae (morning glory, Solanaceae (tobacco, Lamiaceae (mints, Apocynaceae (dogbane have a disproportionate number of psychoactive genera with various indigenous groups using geographically disparate members of these plant families for the same psychoactive effect, an example of cultural convergence. Pharmacological traits related to hallucinogenic and sedative potential are phylogenetically conserved within families. Unrelated families that exert similar psychoactive effects also modulate similar neurotransmitter systems (i.e., mechanistic convergence. However, pharmacological mechanisms for stimulant effects were varied even within families suggesting that stimulant chemicals may be more evolutionarily labile than those associated with hallucinogenic and sedative effects. Chemically similar psychoactive chemicals may also exist in phylogenetically unrelated lineages, suggesting convergent evolution or differential gene regulation of a common metabolic pathway. Our study has shown that phylogenetic analysis of traditionally used psychoactive plants

  7. Neighbour Origin and Ploidy Level Drive Impact of an Alien Invasive Plant Species in a Competitive Environment.

    Directory of Open Access Journals (Sweden)

    Yan Sun

    Full Text Available Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-polycarpic tetraploids. However, only tetraploids have been found in its introduced range in North America, where C. stoebe has become a most prominent plant invader. Here, we focus on the ploidy level of C. stoebe and origin of neighbouring community in explaining the high impact during the invasion of new sites in the introduced range. We conducted a mesocosm experiment under open-field conditions with the diploid (EU2x and tetraploid (EU4x cytotype of Centaurea stoebe from its native European (EU range, and with the invasive tetraploid (NA4x cytotype from the introduced North American (NA range in competition with EU (old or NA (new neighbouring plant communities. In the presence of competition, the biomass of EU neighbouring community was reduced to a comparable level by all three geo-cytotypes of C. stoebe. In contrast, the biomass of the NA neighbouring community was reduced beyond when competing with tetraploid, but not with diploid C. stoebe. The fact that the biomass of all three geo-cytotypes of C. stoebe was correlated with the biomass of the EU neighbouring community, but not with that of the NA neighbouring community suggests that different mechanisms underlie the competitive interactions between C. stoebe and its old vs. new neighbouring communities, such as competition for the same limiting resources at home vs competition through novel allelo-chemicals or differential resource uptake strategies in the introduced range. We therefore caution to simply use the ecosystem impact assessed at home to predict impact in the introduced range.

  8. Phycospheric Native Bacteria Pelagibaca bermudensis and Stappia sp. Ameliorate Biomass Productivity of Tetraselmis striata (KCTC1432BP) in Co-cultivation System through Mutualistic Interaction

    Science.gov (United States)

    Park, Jungsoo; Park, Bum Soo; Wang, Pengbin; Patidar, Shailesh K.; Kim, Jin Ho; Kim, Sae-Hee; Han, Myung-Soo

    2017-01-01

    Effective sustainable algal cultivation techniques are essential for mass production of the marine microalga Tetraselmis for biofuel and array of co-products. The phycospheric communities affect the microalgal growth and metabolism through various allelochemical and nutrient interactions; hence, their potential to affect the quantity and quality of both biomass and bioproducts is significant. In the present study, we have screened the phycospheric communities of biofuel producing Tetraselmis striata (KCTC1432BP). A total of 26 bacterial strains were isolated and identified from the phycosphere of T. striata mass culture. Then, each bacterial strain was tested in co-cultivation conditions with T. striata for evaluating its growth promoting and inhibitory effects. Among these all strains, two promising strains (Pelagibaca bermudensis KCTC 13073BP and Stappia sp. KCTC 13072BP) were selected because of their maximum growth promoting effects and mutualistic interactions. The growth rate, biomass productivity, lipid contents, and fatty acids were analyzed during their combined growth in O3 media and compared with axenic growth of T. striata. Later, growth promoting mechanisms in the co-cultivation environment were investigated for these promising bacterial strains under replete and limited conditions of nutrients (nitrate, phosphate, and vitamin B12). The growth promoting potential of P. bermudensis was illustrated by the two fold enhancement in biomass productivity. These bacteria are promising for microalgal cultivation without any negative effects on the native seawater bacterial communities, as revealed by next generation sequencing analysis. This study represents, to date, the first report highlighting the role of phycospheric growth promoting bacteria of promising biofuel feedstock T. striata. PMID:28321229

  9. Effect of Ent-Kaurene diterpenoid Leukameninon E on phospholipase D and antioxidant enzymes from Arabidopsis thaliana callus%对映-贝壳杉烷型二萜化合物Leukamenin E对拟南芥愈伤组织磷脂酶D及抗氧化物酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    杨宁; 丁芳霞; 陈锡莲; 王程亮; 王丽佩; 丁兰; 安黎哲

    2013-01-01

    Taking Arabidopsis thaliana callus as material, we studied the mechanism of PLD and its antioxidant enzyme response to the allelochemical potential diterpene compound Leukameninon E. The results showed that these membrane-associated PLD activities in mitochondrial and microsomal peaked at hour 36 and 24 at concentration of 100 µmol/L and 200 µmol/L, respectively. Also, the real-time fluorescent quantitative PCR analyses suggested that PLD gene expression was induced by Leukamenin E. With the prolonging of Leukamenin E treatment, the H2O2 content was raised gradually, the activities of SOD, POD, CAT and APX first increased and then decreased. These indicated that Leukamenin E could influence PLD and antioxidant enzyme activity, which are closely related to the membrane stability and respond positively to Leukamenin E stress.%以拟南芥愈伤组织为材料,研究磷脂酶D和抗氧化酶系对具有化感潜能的二萜化合物Leukamenin E的响应机制。结果表明:100µmol/L Leukamenin E处理36 h时线粒体膜结合态PLD活性最高,200µmol/L Leukamenin E处理24 h时微粒体膜结合态PLD活性最高。 PLD基因实时荧光定量PCR分析表明该基因的表达受Leukamenin E诱导。随着Leukamenin E作用时间的延长, H2O2浓度逐渐升高, SOD, POD, CAT, APX活性总体呈先升高后降低的趋势。说明Leukamenin E能够影响与膜稳定性密切相关的PLD和抗氧化酶活性,这二者都积极响应了Leukamenin E的胁迫。

  10. The ethnobotany of psychoactive plant use: a phylogenetic perspective

    Science.gov (United States)

    2016-01-01

    Psychoactive plants contain chemicals that presumably evolved as allelochemicals but target certain neuronal receptors when consumed by humans, altering perception, emotion and cognition. These plants have been used since ancient times as medicines and in the context of religious rituals for their various psychoactive effects (e.g., as hallucinogens, stimulants, sedatives). The ubiquity of psychoactive plants in various cultures motivates investigation of the commonalities among these plants, in which a phylogenetic framework may be insightful. A phylogeny of culturally diverse psychoactive plant taxa was constructed with their psychotropic effects and affected neurotransmitter systems mapped on the phylogeny. The phylogenetic distribution shows multiple evolutionary origins of psychoactive families. The plant families Myristicaceae (e.g., nutmeg), Papaveraceae (opium poppy), Cactaceae (peyote), Convolvulaceae (morning glory), Solanaceae (tobacco), Lamiaceae (mints), Apocynaceae (dogbane) have a disproportionate number of psychoactive genera with various indigenous groups using geographically disparate members of these plant families for the same psychoactive effect, an example of cultural convergence. Pharmacological traits related to hallucinogenic and sedative potential are phylogenetically conserved within families. Unrelated families that exert similar psychoactive effects also modulate similar neurotransmitter systems (i.e., mechanistic convergence). However, pharmacological mechanisms for stimulant effects were varied even within families suggesting that stimulant chemicals may be more evolutionarily labile than those associated with hallucinogenic and sedative effects. Chemically similar psychoactive chemicals may also exist in phylogenetically unrelated lineages, suggesting convergent evolution or differential gene regulation of a common metabolic pathway. Our study has shown that phylogenetic analysis of traditionally used psychoactive plants suggests

  11. Flavin-dependent monooxygenases as a detoxification mechanism in insects: new insights from the arctiids (lepidoptera.

    Directory of Open Access Journals (Sweden)

    Sven Sehlmeyer

    Full Text Available Insects experience a wide array of chemical pressures from plant allelochemicals and pesticides and have developed several effective counterstrategies to cope with such toxins. Among these, cytochrome P450 monooxygenases are crucial in plant-insect interactions. Flavin-dependent monooxygenases (FMOs seem not to play a central role in xenobiotic detoxification in insects, in contrast to mammals. However, the previously identified senecionine N-oxygenase of the arctiid moth Tyria jacobaeae (Lepidoptera indicates that FMOs have been recruited during the adaptation of this insect to plants that accumulate toxic pyrrolizidine alkaloids. Identification of related FMO-like sequences of various arctiids and other Lepidoptera and their combination with expressed sequence tag (EST data and sequences emerging from the Bombyx mori genome project show that FMOs in Lepidoptera form a gene family with three members (FMO1 to FMO3. Phylogenetic analyses suggest that FMO3 is only distantly related to lepidopteran FMO1 and FMO2 that originated from a more recent gene duplication event. Within the FMO1 gene cluster, an additional gene duplication early in the arctiid lineage provided the basis for the evolution of the highly specific biochemical, physiological, and behavioral adaptations of these butterflies to pyrrolizidine-alkaloid-producing plants. The genes encoding pyrrolizidine-alkaloid-N-oxygenizing enzymes (PNOs are transcribed in the fat body and the head of the larvae. An N-terminal signal peptide mediates the transport of the soluble proteins into the hemolymph where PNOs efficiently convert pro-toxic pyrrolizidine alkaloids into their non-toxic N-oxide derivatives. Heterologous expression of a PNO of the generalist arctiid Grammia geneura produced an N-oxygenizing enzyme that shows noticeably expanded substrate specificity compared with the related enzyme of the specialist Tyria jacobaeae. The data about the evolution of FMOs within lepidopteran insects

  12. Neighbour Origin and Ploidy Level Drive Impact of an Alien Invasive Plant Species in a Competitive Environment.

    Science.gov (United States)

    Sun, Yan; Müller-Schärer, Heinz; Schaffner, Urs

    2016-01-01

    Our understanding of the potential mechanisms driving the spread and naturalization of alien plant species has increased over the past decades, but specific knowledge on the factors contributing to their increased impact in the introduced range is still urgently needed. The native European plant Centaurea stoebe occurs as two cytotypes with different life histories (monocarpic diploids, allo-polycarpic tetraploids). However, only tetraploids have been found in its introduced range in North America, where C. stoebe has become a most prominent plant invader. Here, we focus on the ploidy level of C. stoebe and origin of neighbouring community in explaining the high impact during the invasion of new sites in the introduced range. We conducted a mesocosm experiment under open-field conditions with the diploid (EU2x) and tetraploid (EU4x) cytotype of Centaurea stoebe from its native European (EU) range, and with the invasive tetraploid (NA4x) cytotype from the introduced North American (NA) range in competition with EU (old) or NA (new) neighbouring plant communities. In the presence of competition, the biomass of EU neighbouring community was reduced to a comparable level by all three geo-cytotypes of C. stoebe. In contrast, the biomass of the NA neighbouring community was reduced beyond when competing with tetraploid, but not with diploid C. stoebe. The fact that the biomass of all three geo-cytotypes of C. stoebe was correlated with the biomass of the EU neighbouring community, but not with that of the NA neighbouring community suggests that different mechanisms underlie the competitive interactions between C. stoebe and its old vs. new neighbouring communities, such as competition for the same limiting resources at home vs competition through novel allelo-chemicals or differential resource uptake strategies in the introduced range. We therefore caution to simply use the ecosystem impact assessed at home to predict impact in the introduced range.

  13. Application of PCR-denaturing-gradient gel electrophoresis (DGGE) method to examine microbial community structure in asparagus fields with growth inhibition due to continuous cropping.

    Science.gov (United States)

    Urashima, Yasufumi; Sonoda, Takahiro; Fujita, Yuko; Uragami, Atsuko

    2012-01-01

    Growth inhibition due to continuous cropping of asparagus is a major problem; the yield of asparagus in replanted fields is low compared to that in new fields, and missing plants occur among young seedlings. Although soil-borne disease and allelochemicals are considered to be involved in this effect, this is still controversial. We aimed to develop a technique for the biological field diagnosis of growth inhibition due to continuous cropping. Therefore, in this study, fungal community structure and Fusarium community structure in continuously cropped fields of asparagus were analyzed by polymerase chain reaction/denaturing-gradient gel electrophoresis (PCR-DGGE). Soil samples were collected from the Aizu region of Fukushima Prefecture, Japan. Soil samples were taken from both continuously cropped fields of asparagus with growth inhibition and healthy neighboring fields of asparagus. The soil samples were collected from the fields of 5 sets in 2008 and 4 sets in 2009. We were able to distinguish between pathogenic and non-pathogenic Fusarium by using Alfie1 and Alfie2GC as the second PCR primers and PCR-DGGE. Fungal community structure was not greatly involved in the growth inhibition of asparagus due to continuous cropping. By contrast, the band ratios of Fusarium oxysporum f. sp. asparagi in growth-inhibited fields were higher than those in neighboring healthy fields. In addition, there was a positive correlation between the band ratios of Fusarium oxysporum f. sp. asparagi and the ratios of missing asparagus plants. We showed the potential of biological field diagnosis of growth inhibition due to continuous cropping of asparagus using PCR-DGGE.

  14. Allelopathic Effect of Cassava on Companion Weeds%木薯对伴生杂草化感作用的初步研究

    Institute of Scientific and Technical Information of China (English)

    程汉亭; 沈奕德; 黄乔乔; 李晓霞; 刘丽珍; 范志伟

    2013-01-01

    Using Brassica pekinensis and companion weeds (Praxelis clematidea and Bidens pilosa) in cassava plantations as target plants,the allelopathic effects of four extracts of cassava fresh leaves were investigated using bioassays.The extracts differentially inhibited germination and seedling growth (root and stem length) in a dose related manner.Ethyl-acetate and water extracts were more inhibitory than methanol and chloroform extracts.Cassava-leaf extracts contain allelochemicals that inhibit germination and growth of P.s clematidea and B.pilosa.This provides a theoretical basis to study the allelopathic potential of cassava varieties.%以白菜和木薯园伴生杂草(假臭草、三叶鬼针草)为受体植物,采用生物测定的方法研究了新鲜木薯叶片4种浸提液的化感作用.结果表明,4种浸提液对受体植物种子萌发率、根长和茎长的生长发育均有不同程度的抑制作用,且浓度越大抑制作用越强;其中乙酸乙酯和水浸提液的抑制作用较强,甲醇和氯仿浸提液的抑制作用相对较弱.研究表明,木薯叶浸提液中含有抑制伴生杂草(假臭草和三叶鬼针草)种子萌发和幼苗生长的化感物质,为进一步开展具有化感潜力木薯品种的研究提供了理论基础.

  15. Nuclear receptors HR96 and ultraspiracle from the fall armyworm (Spodoptera frugiperda), developmental expression and induction by xenobiotics.

    Science.gov (United States)

    Giraudo, Maeva; Audant, Pascaline; Feyereisen, René; Le Goff, Gaëlle

    2013-05-01

    The fall armyworm Spodoptera frugiperda is a major polyphagous pest in agriculture and little is known on how this insect can adapt to the diverse and potentially toxic plant allelochemicals that they ingest or to insecticides. To investigate the involvement of nuclear receptors in the response of S. frugiperda to its chemical environment, we cloned SfHR96, a nuclear receptor orthologous to the mammalian xenobiotic receptors, pregnane X receptor (PXR) and constitutive androstane receptor (CAR). We also cloned ultraspiracle (USP), the ortholog of retinoid X receptor (RXR) that serves as partner of dimerization of PXR and CAR. Cloning of SfUSP revealed the presence of two isoforms, SfUSP-1 and SfUSP-2 in this species, that differ in their N-terminal region. The expression of these receptors as well as the ecdysone receptor was studied during specific steps of development in different tissues. SfHR96 was constitutively expressed in larval midgut, fat body and Malpighian tubules throughout the last two instars and pupal stage, as well as in Sf9 cells. EcR and SfUSP-2 showed peaks of expression before larval moults and during metamorphosis, whereas SfUSP-1 was mainly expressed in the pre-pupal stage. Receptor induction was followed after exposure of larvae or cells to 11 chemical compounds. SfHR96 was not inducible by the tested compounds. EcR was significantly induced by the 20-hydroxyecdysone agonist, methoxyfenozide, and SfUSP showed an increase expression when exposed to the juvenile hormone analog, methoprene. The cloning of these nuclear receptors is a first step in understanding the important capacities of adaptation of this insect pest.

  16. Differential toxic effects of Ulva lactuca (Chlorophyta) on the herbivorous gastropods, Littorina littorea and L. obtusata (Mollusca).

    Science.gov (United States)

    Peckol, Paulette; Putnam, Alysha B

    2016-12-28

    Members of the genus Ulva are widespread and abundant in intertidal and shallow subtidal areas but there are conflicting data regarding susceptibility to herbivory. While some studies have documented that Ulva spp. were favored by a diversity of marine herbivores, other work has revealed herbivore deterrence. We investigated grazing and growth rates of the littorinid species, Littorina littorea and L. obtusata, when offered Fucus vesiculosus, Ascophyllum nodosum, Ulva lactuca, and Chondrus crispus, highlighting distinctive vulnerabilities to toxic effects of U. lactuca. Ulva lactuca was the preferred food of L. littorea, while L. obtusata showed no grazing on this ephemeral algal species. In contrast, F. vesiculosus was highly preferred by L. obtusata. Although L. littorea demonstrated a grazing preference for U. lactuca, growth rate of this gastropod species was nearly 3× greater when fed F. vesiculosus, suggesting a non-lethal, negative effect of U. lactuca on L. littorea with long-term exposure. Mortality of L. obtusata ranged from 0% to 100% when held in the presence of various Ulva densities for 1 week, and Ulva exudate depressed herbivory of this gastropod. We conclude that the water-soluble, toxic exudate produced by U. lactuca in response to herbivory had allelochemical properties, and may contain a cleavage product (acrylic acid) of dimethylsulfoniopropionate or reactive oxygen species (i.e., H2 O2 ). Observed differences in susceptibility to Ulva toxicity by the littorinid species may be related to generalist versus specialist feeding and habitat strategies.

  17. Multifaceted biological insights from a draft genome sequence of the tobacco hornworm moth, Manduca sexta.

    Science.gov (United States)

    Kanost, Michael R; Arrese, Estela L; Cao, Xiaolong; Chen, Yun-Ru; Chellapilla, Sanjay; Goldsmith, Marian R; Grosse-Wilde, Ewald; Heckel, David G; Herndon, Nicolae; Jiang, Haobo; Papanicolaou, Alexie; Qu, Jiaxin; Soulages, Jose L; Vogel, Heiko; Walters, James; Waterhouse, Robert M; Ahn, Seung-Joon; Almeida, Francisca C; An, Chunju; Aqrawi, Peshtewani; Bretschneider, Anne; Bryant, William B; Bucks, Sascha; Chao, Hsu; Chevignon, Germain; Christen, Jayne M; Clarke, David F; Dittmer, Neal T; Ferguson, Laura C F; Garavelou, Spyridoula; Gordon, Karl H J; Gunaratna, Ramesh T; Han, Yi; Hauser, Frank; He, Yan; Heidel-Fischer, Hanna; Hirsh, Ariana; Hu, Yingxia; Jiang, Hongbo; Kalra, Divya; Klinner, Christian; König, Christopher; Kovar, Christie; Kroll, Ashley R; Kuwar, Suyog S; Lee, Sandy L; Lehman, Rüdiger; Li, Kai; Li, Zhaofei; Liang, Hanquan; Lovelace, Shanna; Lu, Zhiqiang; Mansfield, Jennifer H; McCulloch, Kyle J; Mathew, Tittu; Morton, Brian; Muzny, Donna M; Neunemann, David; Ongeri, Fiona; Pauchet, Yannick; Pu, Ling-Ling; Pyrousis, Ioannis; Rao, Xiang-Jun; Redding, Amanda; Roesel, Charles; Sanchez-Gracia, Alejandro; Schaack, Sarah; Shukla, Aditi; Tetreau, Guillaume; Wang, Yang; Xiong, Guang-Hua; Traut, Walther; Walsh, Tom K; Worley, Kim C; Wu, Di; Wu, Wenbi; Wu, Yuan-Qing; Zhang, Xiufeng; Zou, Zhen; Zucker, Hannah; Briscoe, Adriana D; Burmester, Thorsten; Clem, Rollie J; Feyereisen, René; Grimmelikhuijzen, Cornelis J P; Hamodrakas, Stavros J; Hansson, Bill S; Huguet, Elisabeth; Jermiin, Lars S; Lan, Que; Lehman, Herman K; Lorenzen, Marce; Merzendorfer, Hans; Michalopoulos, Ioannis; Morton, David B; Muthukrishnan, Subbaratnam; Oakeshott, John G; Palmer, Will; Park, Yoonseong; Passarelli, A Lorena; Rozas, Julio; Schwartz, Lawrence M; Smith, Wendy; Southgate, Agnes; Vilcinskas, Andreas; Vogt, Richard; Wang, Ping; Werren, John; Yu, Xiao-Qiang; Zhou, Jing-Jiang; Brown, Susan J; Scherer, Steven E; Richards, Stephen; Blissard, Gary W

    2016-09-01

    Manduca sexta, known as the tobacco hornworm or Carolina sphinx moth, is a lepidopteran insect that is used extensively as a model system for research in insect biochemistry, physiology, neurobiology, development, and immunity. One important benefit of this species as an experimental model is its extremely large size, reaching more than 10 g in the larval stage. M. sexta larvae feed on solanaceous plants and thus must tolerate a substantial challenge from plant allelochemicals, including nicotine. We report the sequence and annotation of the M. sexta genome, and a survey of gene expression in various tissues and developmental stages. The Msex_1.0 genome assembly resulted in a total genome size of 419.4 Mbp. Repetitive sequences accounted for 25.8% of the assembled genome. The official gene set is comprised of 15,451 protein-coding genes, of which 2498 were manually curated. Extensive RNA-seq data from many tissues and developmental stages were used to improve gene models and for insights into gene expression patterns. Genome wide synteny analysis indicated a high level of macrosynteny in the Lepidoptera. Annotation and analyses were carried out for gene families involved in a wide spectrum of biological processes, including apoptosis, vacuole sorting, growth and development, structures of exoskeleton, egg shells, and muscle, vision, chemosensation, ion channels, signal transduction, neuropeptide signaling, neurotransmitter synthesis and transport, nicotine tolerance, lipid metabolism, and immunity. This genome sequence, annotation, and analysis provide an important new resource from a well-studied model insect species and will facilitate further biochemical and mechanistic experimental studies of many biological systems in insects.

  18. Effects of Quinizarin and Five Synthesized Derivatives on Fifth Larval Instar Midgut Ecdysone 20-Monooxygenase Activity of the Tobacco Hornworm Manduca sexta

    Directory of Open Access Journals (Sweden)

    Christopher A. Drummond

    2014-01-01

    Full Text Available The plant allelochemical, quinizarin (1,4-dihydroxy-9,10-anthraquinone, and five anthraquinones that were synthesized from quinizarin, namely, 1,4-anthraquinone; 2-hydroxy-1,4-anthraquinone; 2-methoxy-1,4-anthraquinone; 9-hydroxy-1,4-anthraquinone; and 9-methoxy-1,4-anthraquinone, were assessed as to their effects on the essential, P450-dependent ecdysone 20-monooxygenase system of the insect model Manduca sexta (tobacco hornworm. This steroid hydroxylase converts the arthropod molting hormone, ecdysone, to the physiologically required 20-hydroxyecdysone form. M. sexta fifth larval instar midgut homogenates were incubated with increasing concentrations (10−8 to 10−3 M of each of the six anthraquinones followed by ecdysone 20-monooxygenase assessments using a radioenzymological assay. Four of the five anthraquinones exhibited I50’s of about 4×10-6 to 6×10-2 M. The most effective inhibitors were 2-methoxy-1,4-anthraquinone and 1,4-anthraquinone followed by 9-hydroxy-1,4 anthraquinone and 9-methoxy-1,4-anthraquinone. At lower concentrations the latter anthraquinone stimulated E20M activity. Quinizarin was less inhibitory and 2-hydroxy-1,4-anthraquinone was essentially without effect. Significantly, these studies make evident for the first time that anthraquinones can affect insect E20M activity, and thus insect endocrine regulation and development, and that a relationship between anthraquinone structure and effectiveness is apparent. These studies represent the first demonstrations of anthraquinones affecting any steroid hydroxylase system.

  19. Allelopathic potential and ecotoxicity evaluation of gallic and nonanoic acids to prevent cyanobacterial growth in lentic systems: A preliminary mesocosm study.

    Science.gov (United States)

    Techer, Didier; Fontaine, Pascal; Personne, Aline; Viot, Sandrine; Thomas, Marielle

    2016-03-15

    The increase in anthropogenic nutrient loading affecting many freshwater ecosystems combined with global warming may lead to cyanobacterial blooms on an increasingly frequent basis. Among the various physicochemical and biological methods which have been proposed to rapidly control blue-green algae growth, the use of plant-derived substances such as allelochemicals has gained great interest as an environment-friendly approach. The primary aim of this work was to evaluate the efficiency of gallic and nonanoic acid application to preemptively inhibit cyanobacterial growth in lentic hydrosystems. In order to address the process feasibility under realistic exposure scenarios, thirteen outdoor freshwater mesocosms (unit volume: 3m(3)) were designed, each containing phytoplankton (including local blue-green algae species) and various non-target organisms from higher trophic levels (Physa, Lymnaea, Gammarus, and Scardinius erythrophthalmus). After an 8-week mesocosm stabilization period, a full factorial design based on the presence/absence of gallic acid (GA) and nonanoic acid (NA) (including a control group) was implemented into the exposure tanks. Regular monitoring of major phytoplankton taxa was conducted during a 28-day experiment using an on-line fluorometer. The main results suggested that gallic acid was more efficient than nonanoic acid at limiting cyanobacterial growth at concentrations as low as 1 mg L(-1). Successive gallic acid applications (at 1, 2 and 4 mg L(-1)) at the early stages of cyanobacterial growth did not allow the complete elimination of blue-green algae from the mesocosms. However, the specificity of the allelopathic effect of gallic acid towards cyanobacteria was compatible with the maintenance of a primary productivity in the treated tanks as indicated by the photoautotrophic growth of other algal taxa. Finally, no biomarker induction signal could be reported in non-target species. Further gallic acid application trials in lentic systems such

  20. Effect of extracts of Chinese pine on its own seed germination and seedling growth

    Institute of Scientific and Technical Information of China (English)

    Meiqiu ZHU; Changming MA; Ying WANG; Lili ZHANG; Hui WANG; Yuxin YUAN; Kejiu DU

    2009-01-01

    The allelopathic potential of Chinese pine (Pinus tabulaeformis Carr.) against its own seed germination and seedling growth was tested with aqueous extracts (0.01, 0.02, 0.05, and 0.10 g·mL-1) obtained from different organs (roots and litter needles) at different individual ages (12, 52, and 110 years old). The results showed that root and litter extracts had different effects on seed germination and seedling growth, and the effects varied with the concentrations, the organs, and the tree age of extracts. The strongest stimulatory effect on seed germination of Chinese pine was exposed to 0.02g·mL-1 root extract from the 110 years old Chinese pine trees and exposed to 0.02 g·mL-1 litter extract from the 12 years old Chinese pine trees. Meanwhile, the strongest stimulatory effect on growth of Chinese pine seedlings was exposed not only to 0.01 g·mL-1 root extracts from the 110 years old Chinese pine but also to 0.01 g·mL-1 litter extract from the 12 years old Chinese pine. The promoting effect of the extracts of root on seed germination and seedling growth increased in the order of 12, 52, and 110 years old. The promoting effect of the extracts of litter on seed germination and seedling growth increased in the order of 110, 52, and 12 years old. Our results suggested that litter leachates or root exudates of Chinese pine may influence the natural regeneration within Chinese pine stands via the release of allelochemicals into the environment.

  1. Broomrape Weeds. Underground Mechanisms of Parasitism and Associated Strategies for their Control: A Review.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Reboud, Xavier; Gibot-Leclerc, Stephanie

    2016-01-01

    Broomrapes are plant-parasitic weeds which constitute one of the most difficult-to-control of all biotic constraints that affect crops in Mediterranean, central and eastern Europe, and Asia. Due to their physical and metabolic overlap with the crop, their underground parasitism, their achlorophyllous nature, and hardly destructible seed bank, broomrape weeds are usually not controlled by management strategies designed for non-parasitic weeds. Instead, broomrapes are in current state of intensification and spread due to lack of broomrape-specific control programs, unconscious introduction to new areas and may be decline of herbicide use and global warming to a lesser degree. We reviewed relevant facts about the biology and physiology of broomrape weeds and the major feasible control strategies. The points of vulnerability of some underground events, key for their parasitism such as crop-induced germination or haustorial development are reviewed as inhibition targets of the broomrape-crop association. Among the reviewed strategies are those aimed (1) to reduce broomrape seed bank viability, such as fumigation, herbigation, solarization and use of broomrape-specific pathogens; (2) diversion strategies to reduce the broomrape ability to timely detect the host such as those based on promotion of suicidal germination, on introduction of allelochemical interference, or on down-regulating host exudation of germination-inducing factors; (3) strategies to inhibit the capacity of the broomrape seedling to penetrate the crop and connect with the vascular system, such as biotic or abiotic inhibition of broomrape radicle growth and crop resistance to broomrape penetration either natural, genetically engineered or elicited by biotic- or abiotic-resistance-inducing agents; and (4) strategies acting once broomrape seedling has bridged its vascular system with that of the host, aimed to impede or to endure the parasitic sink such as those based on the delivery of herbicides via

  2. Direct and indirect effects of invasive plants on soil chemistry and ecosystem function.

    Science.gov (United States)

    Weidenhamer, Jeffrey D; Callaway, Ragan M

    2010-01-01

    Invasive plants have a multitude of impacts on plant communities through their direct and indirect effects on soil chemistry and ecosystem function. For example, plants modify the soil environment through root exudates that affect soil structure, and mobilize and/or chelate nutrients. The long-term impact of litter and root exudates can modify soil nutrient pools, and there is evidence that invasive plant species may alter nutrient cycles differently from native species. The effects of plants on ecosystem biogeochemistry may be caused by differences in leaf tissue nutrient stoichiometry or secondary metabolites, although evidence for the importance of allelochemicals in driving these processes is lacking. Some invasive species may gain a competitive advantage through the release of compounds or combinations of compounds that are unique to the invaded community—the “novel weapons hypothesis.” Invasive plants also can exert profound impact on plant communities indirectly through the herbicides used to control them. Glyphosate, the most widely used herbicide in the world, often is used to help control invasive weeds, and generally is considered to have minimal environmental impacts. Most studies show little to no effect of glyphosate and other herbicides on soil microbial communities. However, herbicide applications can reduce or promote rhizobium nodulation and mycorrhiza formation. Herbicide drift can affect the growth of non-target plants, and glyphosate and other herbicides can impact significantly the secondary chemistry of plants at sublethal doses. In summary, the literature indicates that invasive species can alter the biogeochemistry of ecosystems, that secondary metabolites released by invasive species may play important roles in soil chemistry as well as plant-plant and plant-microbe interactions, and that the herbicides used to control invasive species can impact plant chemistry and ecosystems in ways that have yet to be fully explored.

  3. Broomrape weeds. Underground mechanisms of parasitism and associated strategies for their control: a review.

    Directory of Open Access Journals (Sweden)

    Monica eFernandez-Aparicio

    2016-02-01

    Full Text Available Broomrapes are plant-parasitic weeds which constitute one of the most difficult-to-control of all biotic constraints that affect crops in Mediterranean, central and eastern Europe, and Asia. Due to their physical and metabolic overlap with the crop, their underground parasitism, their achlorophyllous nature, and hardly destructible seed bank, broomrape weeds are usually not controlled by management strategies designed for non-parasitic weeds. Instead, broomrape are in a current state of intensification and spread due to lack of broomrape-specific control programs, unconscious introduction to new areas and may be decline of herbicide use and global warming to a lesser degree. We reviewed relevant facts about the biology and physiology of broomrape weeds and the major feasible control strategies. The points of vulnerability of some underground events, key for their parasitism such as crop-induced germination or haustorial development are reviewed as inhibition targets of the broomrape-crop association. Among the reviewed strategies are those aimed 1 to reduce broomrape seed bank viability, such as fumigation, herbigation, solarization and use of broomrape-specific pathogens; 2 diversion strategies to reduce the broomrape ability to timely detect the host such as those based on promotion of suicidal germination, on introduction of allelochemical interference, or on down-regulating host exudation of germination-inducing factors; 3 strategies to inhibit the capacity of the broomrape seedling to penetrate the crop and connect with the vascular system, such as biotic or abiotic inhibition of broomrape radicle growth, crop resistance to broomrape penetration either natural, genetically engineered or elicited by biotic- or abiotic-resistance-inducing agents and 4 strategies acting once broomrape seedling has bridged its vascular system with that of the host, aimed to impede or to endure the parasitic sink such as those based on the delivery of herbicides

  4. Interactions between Bacteria And Aspen Defense Chemicals at the Phyllosphere - Herbivore Interface.

    Science.gov (United States)

    Mason, Charles J; Lowe-Power, Tiffany M; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2016-03-01

    Plant- and insect-associated microorganisms encounter a diversity of allelochemicals, and require mechanisms for contending with these often deleterious and broadly-acting compounds. Trembling aspen, Populus tremuloides, contains two principal groups of defenses, phenolic glycosides (salicinoids) and condensed tannins, which differentially affect the folivorous gypsy moth, Lymantria dispar, and its gut symbionts. The bacteria genus Acinetobacter is frequently associated with both aspen foliage and gypsy moth consuming that tissue, and one isolate, Acinetobacter sp. R7-1, previously has been shown to metabolize phenolic glycosides. In this study, we aimed to characterize further interactions between this Acinetobacter isolate and aspen secondary metabolites. We assessed bacterial carbon utilization and growth in response to different concentrations of phenolic glycosides and condensed tannins. We also tested if enzyme inhibitors reduce bacterial growth and catabolism of phenolic glycosides. Acinetobacter sp. R7-1 utilized condensed tannins but not phenolic glycosides or glucose as carbon sources. Growth in nutrient-rich medium was increased by condensed tannins, but reduced by phenolic glycosides. Addition of the P450 enzyme inhibitor piperonyl butoxide increased the effects of phenolic glycosides on Acinetobacter sp. R7-1. In contrast, the esterase inhibitor S,S,S,-tributyl-phosphorotrithioate did not affect phenolic glycoside inhibition of bacterial growth. Degradation of phenolic glycosides by Acinetobacter sp. R7-1 appears to alleviate the cytotoxicity of these compounds, rather than provide an energy source. Our results further suggest this bacterium utilizes additional, complementary mechanisms to degrade antimicrobial phytochemicals. Collectively, these results provide insight into mechanisms by which microorganisms contend with their environment within the context of plant-herbivore interactions.

  5. Weeds from Between-row Crop Elimination Method Based on Scale-free Networks%基于无尺度网络的行间作物杂草清除方法

    Institute of Scientific and Technical Information of China (English)

    聂笑一; 杨长兴

    2009-01-01

    为了减少除草剂在经济作物上的使用,降低除草剂对环境的压力,本文提出采用机器视觉识别杂草网络、对行间作物杂草无尺度网络摧毁的方法.通过机器视觉识别出作物、土壤和杂草,依据植化物质的作用建立并绘制杂草无尺度网络,通过对杂草网络的节点偏好性、增长性和聚类性的研究,发现杂草网络对随机节点故障具有鲁棒性,对蓄意攻击具有脆弱性,依据此特点提出摧毁杂草网络节点的方法.与现有方法相比,新方法符合生态经济管理原则.%In order to reduce the herbicide on crops and stress on the environment, this paper proposes to use machine vision to identify weed networks, and destroyes network of weeds from between-row crop by scale-free networks method. The paper identifies the crop, soil and weeds by machine vision, builts and mappes scale-free networks of weed according to the role of allelochemics, researches weed networks of preferential attachment, growth and clustering, founds that error tolerance and attack vulnerability are generic properties of weed networks, and proposes a method to attack and destroy weed networks. Compared with existing methods, new methods accord with the principle of eco-economic management.

  6. [Allelopathic effects of extracts from tuberous roots of Aconitum carmichaeli on three pasture grasses].

    Science.gov (United States)

    Jiao, Yu-jie; Wang, Ya-qi; Yuan, Ling

    2015-11-01

    The tuberous roots of Aconitum carmichaeli are largely used in traditional Chinese medicine and widely grown in Jiangyou, Sichuan, China. During the growth process, this medicinal plant releases a large amount of allelochemicals into soil, which retard the growth and development of near and late crops. Therefore, a pure culture experiment was thus carried out by seed soaking to study the allelopathic effects of extracts from tuberous roots of A. carmichaeli (ETR) on the seed germination and young seedling growth of Lolium perenne, Trifolium repens, and Medicago sativa, the late pasture grasses after cultivation of A. carmichaeli. The results showed that three pasture grasses varied significantly in seed germination and young seedling growth in response to ETR concentrations. Seed germination of M. sativa was stimulated by low ERT concentration (0.01 x g(-1)), while all of pasture grass seeds germinated poorly in solution with 1.00 g x L(-1). Seed soaking with 1.00 g x L(-1) also inhibited significantly the growth of pasture young seedlings, with M. sativa showing the highest seedling height reduction of 42.05% in seeding height, followed by T. repens (40.21%) and L. perenne with about 11%. Cultivation of L. perenne could thus be beneficial to increase whole land productivity in A. carmichaeli-pasture grass cropping systems. In addition, hydrolysis of protein, starch, and inositol phosphates was blocked and free amino acids, soluble sugars and phosphorus were decreased in seeds by seed soaking with ETR, which could be one of the reason for the inhibition of seed germination. There was a significant reduction in root vigor, nitrate reductase, and chlorophyll after the seed treatment with ETR, indicating the suppression of nutrient uptake, nitrate assimilation, and photosynthesis by allelopathic chemicals in ETR, which could lead to the slow growth rate of pasture grass seedlings.

  7. 植物病原性连作障碍研究进展%Advances in Pathogenic Obstacles for Continuous Cropping of Crops

    Institute of Scientific and Technical Information of China (English)

    梁志怀; 魏林; 李世东; 李基光

    2012-01-01

    作物连作障碍日趋成为影响我国农业可持续发展的重要因素.简要介绍病原性连作障碍的概念,概述了连作栽培条件下根际微生物种群结构变化和根分泌物中碳水化合物及其诱导病原菌种群数量增殖的功能,总结了根分泌物中某些化感物质在增强病原物种群数量中的作用和土壤微生物间的化学通讯分子,展望了今后研究的方向与重点.%The obstacles for continuous cropping of crops had been an important factors which affecting sustainable development of agriculture and forestry in China. The concept of pathogenic obstacles for continuous cropping was briefly introduced at first. Then, the changes in structure of rhizosphere microorganism population, the carbohydrate in root exudates and the function of carbohydrate in root exudates that inducing proliferation of pathogen population under the conditions of continuous cropping were summarized. And then, the effect of soine allelochemicals in root exudates in proliferation of pathogen population and the chemical communication molecular among soil microorganisms were also summarized. In the end, the direction and emphases of the research in the future were prospected.

  8. Ecological shifts in Mediterranean coralligenous assemblages related to gorgonian forest loss.

    Directory of Open Access Journals (Sweden)

    Massimo Ponti

    Full Text Available Mediterranean gorgonian forests are threatened by several human activities and are affected by climatic anomalies that have led to mass mortality events in recent decades. The ecological role of these habitats and the possible consequence of their loss are poorly understood. Effects of gorgonians on the recruitment of epibenthic organisms were investigated by manipulating presence of gorgonians on experimental panels at 24 m depth, for Eunicella cavolinii, and at 40 m depth, for Paramuricea clavata, at two sites: Tavolara Island (Tyrrhenian Sea and Portofino Promontory (Ligurian Sea. After 4 months, the most abundant taxa on the panels were encrusting green algae, erect red algae and crustose coralline algae at 24 m depth and encrusting brown algae and erect red algae at 40 m depth. Assemblages on the panels were significantly affected by the presence of the gorgonians, although effects varied across sites and between gorgonian species. Species diversity and evenness were lower on panels with gorgonian branches. Growth of erect algae and recruitment of serpulid polychaetes were also affected by the presence of the gorgonians, primarily at Tavolara. Crustose coralline algae and erect sponges were more abundant on E. cavolinii panels at 24 m depth, while encrusting bryozoans were more abundant on P. clavata panels at 40 m depth. Effects of gorgonians on recruited assemblages could be due to microscale modification of hydrodynamics and sediment deposition rate, or by a shading effect reducing light intensity. Gorgonians may also intercept settling propagules, compete for food with the filter-feeders and/or for space by producing allelochemicals. Presence of gorgonians mainly limits the growth of erect algae and enhances the abundance of encrusting algae and sessile invertebrates. Therefore, the gorgonian disappearances may cause a shift from assemblages characterised by crustose coralline algae to filamentous algae assemblages, decreasing

  9. In situ oxygen dynamics in coral-algal interactions.

    Directory of Open Access Journals (Sweden)

    Daniel Wangpraseurt

    Full Text Available BACKGROUND: Coral reefs degrade globally at an alarming rate, with benthic algae often replacing corals. However, the extent to which benthic algae contribute to coral mortality, and the potential mechanisms involved, remain disputed. Recent laboratory studies suggested that algae kill corals by inducing hypoxia on the coral surface, through stimulated microbial respiration. METHODS/FINDINGS: We examined the main premise of this hypothesis by measuring in situ oxygen microenvironments at the contact interface between the massive coral Porites spp. and turf algae, and between Porites spp. and crustose coralline algae (CCA. Oxygen levels at the interface were similar to healthy coral tissue and ranged between 300-400 µM during the day. At night, the interface was hypoxic (~70 µM in coral-turf interactions and close to anoxic (~2 µM in coral-CCA interactions, but these values were not significantly different from healthy tissue. The diffusive boundary layer (DBL was about three times thicker at the interface than above healthy tissue, due to a depression in the local topography. A numerical model, developed to analyze the oxygen profiles above the irregular interface, revealed strongly reduced net photosynthesis and dark respiration rates at the coral-algal interface compared to unaffected tissue during the day and at night, respectively. CONCLUSIONS/SIGNIFICANCE: Our results showed that hypoxia was not a consistent feature in the microenvironment of the coral-algal interface under in situ conditions. Therefore, hypoxia alone is unlikely to be the cause of coral mortality. Due to the modified topography, the interaction zone is distinguished by a thicker diffusive boundary layer, which limits the local metabolic activity and likely promotes accumulation of potentially harmful metabolic products (e.g., allelochemicals and protons. Our study highlights the importance of mass transfer phenomena and the need for direct in situ measurements of

  10. The cytochrome P450 superfamily: biochemistry, evolution and drug metabolism in humans.

    Science.gov (United States)

    Danielson, P B

    2002-12-01

    Cytochrome p450s comprise a superfamily of heme-thiolate proteins named for the spectral absorbance peak of their carbon-monoxide-bound species at 450 nm. Having been found in every class of organism, including Archaea, the p450 superfamily is believed to have originated from an ancestral gene that existed over 3 billion years ago. Repeated gene duplications have subsequently given rise to one of the largest of multigene families. These enzymes are notable both for the diversity of reactions that they catalyze and the range of chemically dissimilar substrates upon which they act. Cytochrome p450s support the oxidative, peroxidative and reductive metabolism of such endogenous and xenobiotic substrates as environmental pollutants, agrochemicals, plant allelochemicals, steroids, prostaglandins and fatty acids. In humans, cytochrome p450s are best know for their central role in phase I drug metabolism where they are of critical importance to two of the most significant problems in clinical pharmacology: drug interactions and interindividual variability in drug metabolism. Recent advances in our understanding of cytochrome p450-mediated drug metabolism have been accelerated as a result of an increasing emphasis on functional genomic approaches to p450 research. While human cytochrome p450 databases have swelled with a flood of new human sequence variants, however, the functional characterization of the corresponding gene products has not kept pace. In response researchers have begun to apply the tools of proteomics as well as homology-based and ab initio modeling to salient questions of cytochrome p450 structure/function. This review examines the latest advances in our understanding of human cytochrome p450s.

  11. Helicoverpa zea CYP6B8 and CYP321A1: different molecular solutions to the problem of metabolizing plant toxins and insecticides.

    Science.gov (United States)

    Rupasinghe, Sanjeewa G; Wen, Zhimou; Chiu, Ting-Lan; Schuler, Mary A

    2007-12-01

    Under continual exposure to naturally occurring plant toxins and synthetic insecticides, insects have evolved cytochrome P450 monooxygenases (P450s) capable of metabolizing a wide range of structurally different compounds. Two such P450s, CYP6B8 and CYP321A1, expressed in Helicoverpa zea (a lepidopteran) in response to plant allelochemicals and plant signaling molecules metabolize these compounds with varying efficiencies. While sequence alignments of these proteins indicate highly divergent substrate recognition sites (SRSs), homology models developed for them indicate that the two active site cavities have essentially the same volume with distinct shapes dictated by side-chain differences in SRS1 and SRS5. CYP6B8 has a narrower active site cavity extending from substrate access channel pw2a with a very narrow access to the ferryl oxygen atom. This predicted shape suggests that bulkier molecules bind further from the ferryl oxygen at positions that are not as effectively metabolized. In contrast, CYP321A1 is predicted to have a more spacious cavity allowing larger molecules to access the heme-bound oxygen. The metabolic profiles for several plant toxins (xanthotoxin, angelicin) and insecticides (cypermethrin, aldrin and diazinon) correlate well with these predictive models. The absence of Thr in the I helix of CYP321A1 and hydroxyl groups on many of its substrates suggests that this insect P450 mediates oxygen activation by a mechanism different from that employed by CYP107A1 and CYP158A1, which are two bacterial P450s also lacking Thr in their I helix, and most other P450s that contain Thr in their I helix.

  12. Indirect selection of industrial tomato genotypes that are resistant to spider mites (Tetranychus urticae).

    Science.gov (United States)

    Baier, J E; Resende, J T V; Faria, M V; Schwarz, K; Meert, L

    2015-01-01

    Acyl sugars present in the tomato Solanum lycopersicum 'LA-716' accession confer good levels of resistance to arthropod pests. The objective of the present study was to select F₂ plants from the interspecific cross Solanum pennellii 'LA-716' x Solanum lycopersicum 'Redenção' to assess resistance to spider mites (Tetranychus urticae) based on the leaf acyl sugar content and repellence tests. Four genotypes were selected with high leaflet acyl sugar content (RVTA-2010 pl#31, RVTA-2010 pl#75, RVTA-2010 pl#83, and RVTA-2010 pl#94), and an additional three genotypes with low acyl sugar content were also selected (RVTA-2010 pl#33, RVTA-2010 pl#39, and RVTA-2010 pl#73). The results from the in vivo tests used to confirm the selection of plants resistant to mites indicated that the genotypes with high acyl sugars content did not differ from the resistant parent LA-716. The negative correlation between acyl sugar content and the distance run by the mite along the leaflet surface confirmed the association between high and low allelochemical content and resistance. The medium degree of dominance (MDD) was estimated (MDD = -0.83), indicating that the high acyl sugar content was due to incomplete dominance of a recessive allele. A value of 81.85% was found for the broad sense heritability estimate, which suggests that most among-plant variation in the F2 generation is genetically based. Furthermore, 0.69 genes were estimated, which presumably confirms monogenic inheritance. Thus, indirect selection was an efficient method used to obtain industrial tomato plants that are resistant to spider mites.

  13. The ecological context of pyrrolizidine alkaloids in food, feed and forage: an overview.

    Science.gov (United States)

    Boppré, Michael

    2011-03-01

    Plant-produced 1,2-dehydropyrrolizidine ester alkaloids and their N-oxides (PAs) not only cause acute poisoning of humans and livestock, but also the likely harmful cryptic effects of chronic exposure pose particular food safety risks that need to be addressed for consumer protection. In natural contexts, however, PAs cause few or no problems. Rather, these plant secondary metabolites are important elements of ecosystems and plant-animal relationships; the existence and persistence of many PA-adapted organisms, in various ways, depends on the presence of PA-containing plants or even on PAs as such. PA plants are widely distributed among unrelated families of the plant kingdom; there is great structural diversity of PAs, and the amounts of PAs produced are subject to great variation due to multiple causes. These realities, coupled with many deficiencies in our scientific understanding, make the presence and roles of PAs in nature a subject with limited potential for valid generalisations and predictions, and complex and difficult to summarise. PAs, their producer plants and their users are integral parts of ecosystems worldwide, and we have to learn to live with these allelochemicals by accepting the presence of some harmful natural chemicals in the environment and by taking regulatory action to reduce health risks to humans. Regulations for consumer protection are long overdue. However, any such measures must be flexible enough to accommodate the findings of future research. Transdisciplinary efforts are required to fill gaps in the knowledge and to come up with additional means to monitor the presence of PAs in food and feed.

  14. Effects of climate warming on plant autotoxicity in forest evolution: a case simulation analysis for Picea schrenkiana regeneration.

    Science.gov (United States)

    Ruan, Xiao; Pan, Cun-De; Liu, Run; Li, Zhao-Hui; Li, Shu-Ling; Jiang, De-An; Zhang, Jing-Chi; Wang, Geoff; Zhao, Yin-Xian; Wang, Qiang

    2016-08-01

    In order to explore how plant autotoxicity changes with climate warming, the autotoxicity of P. schrenkiana needles' water extract, organic extract fractions, and key allelochemical DHAP was systemically investigated at the temperature rising 2 and 4°C based on the data-monitored soil temperature during the last decade in the stage of Schrenk spruce regeneration (seed germination and seedling growth). The results showed that the criterion day and night temperatures were 12°C and 4°C for seed germination, and 14°C and 6°C for seedling growth, respectively. In the presence of water extract, the temperature rise of 2°C significantly inhibited the germination vigor and rate of P. Schrenkiana seed, and a temperature rise of 4°C significantly increased the inhibition to the seedling growth (P < 0.05). Among the three organic fractions, the low-polar fraction showed to be more phytotoxic than the other two fractions, causing significant inhibitory effects on the seed germination and growth even at low concentration of 0.1 mg/mL, and the inhibition effect was enhanced as temperature increased. The temperature rise significantly enhanced the promotion effect of DHAP, while the inhibition effect of temperature rise became less important with increasing concentration of DHAP. This investigation revealed that autotoxicity of P. schrenkiana was affected by the climate warming. As expected, it provided an insight into the mechanism and effectiveness of allelopathy in bridging the causal relationship between forest evolution and climate warming.

  15. Effect of Alexandrium tamarense on three bloom-forming algae

    Science.gov (United States)

    Yin, Juan; Xie, Jin; Yang, Weidong; Li, Hongye; Liu, Jiesheng

    2010-07-01

    We investigated the allelopathic properties of Alexandrium tamarense (Laboar) Balech on the growth of Prorocentrum donghaiense Lu, Chattonella marina (Subrahmanyan) Hara et Chihara and Heterosigma akashiwo (Hada) Hada in a laboratory experiment. We examined the growth of A. tamarense, C. marina, P. donghaiense and H. Akashiwo in co-cultures and the effect of filtrates from A. tamarense cultures in various growth phases, on the three harmful algal bloom (HAB)-forming algae. In co-cultures with A. tamarense, both C. marina and H. akashiwo were dramatically suppressed at high cell densities; in contrast, the growth of P. donghaiense varied in different inoculative ratios of A. tamarense and P. donghaiense. When the ratio was 1:1 ( P. donghaiense: A. tamarense), growth of P. donghaiense was inhibited considerably, while the growth of P. donghaiense was almost the same as that of the control when the ratio was 9:1. The growth difference of P. donghaiense, C. marina and H. akashiwo when co-cultured with A. tamarense indicated that the allelopathic effect may be one of the important factors in algal competition and phytoplankton succession involving A. tamarense. In addition, the filtrate from A. tamarense culture had negative impacts on these three HAB algae, and such inhibition varied with different growth phases of A. tamarense in parallel with reported values of PSP toxin content in Alexandrium cells. This implied that PSP toxin was possibly involved in allelopathy of A. tamarense. However, the rapid decomposition and inactivation of PSP toxin above pH 7 weakened this possibility. Further studies on the allelochemicals responsible for the allelopathy of A. tamarense need to be carried out in future.

  16. Allelopathy is involved in the formation of pure colonies of the fern Gleichenia japonica.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Saito, Yoshihumi; Ohno, Osamu; Suenaga, Kiyotake

    2013-04-15

    The fern Gleichenia japonica is one of the most widely distributed fern and occurs throughout East to South Asia. The species often dominates plant communities by forming large monospecific colonies. However, the potential mechanism for this domination has not yet been described. The objective of this study was to test the hypothesis that allelochemicals are involved in the formation of G. japonica colonies. An aqueous methanol extract of G. japonica inhibited the growth of seedlings of garden cress (Lepidium sativum), lettuce (Lactuca sativa), ryegrass (Lolium multiflorum) and timothy (Phleum pratense). Increasing extract concentration increased the inhibition. These results suggest that G. japonica contain allelopathic substances. The extract was then purified by several chromatographies with monitoring the inhibitory activity and two growth inhibitory substances causing the allelopathic effect were isolated. The chemical structures of the two substances were determined by spectral data to be a novel compound 3-O-β-allopyranosyl-13-O-β-fucopyranosyl-3β-hydroxymanool (1) and 18-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl-13-epitorreferol (2). These compounds inhibited the shoot and root growth of garden cress, lettuce, alfalfa (Medicago sativa), timothy, ryegrass and barnyardgrass (Echinochloa crus-galli) at concentrations greater than 0.1-1.0mM. The concentrations required for 50% growth inhibition of root and shoot growth of these test plants ranged from 0.72 to 3.49mM and 0.79 to 3.51mM for compounds 1 and 2, respectively. Concentration of compounds 1 and 2 in soil under the pure colony of G. japonica was 4.9 and 5.7mM, respectively, indicating concentrations over those required for 50% growth inhibition are potentially available under monocultural stands of these ferns. Therefore, these compounds may contribute to the allelopathic effects caused by presence of G. japonica and may thus contribute to the establishment of monocultural stands by this

  17. TRANSFORMATION AND ALLELOPATHY OF NATURAL DISSOLVED ORGANIC CARBON AND TANNIC ACID ARE AFFECTED BY SOLAR RADIATION AND BACTERIA(1).

    Science.gov (United States)

    Bauer, Nadine; Zwirnmann, Elke; Grossart, Hans-Peter; Hilt, Sabine

    2012-04-01

    The aim of this study was to test whether abiotic and biotic factors may affect allelopathic properties. Therefore, we investigated how solar radiation and bacteria influence allelopathic effects of the plant-derived, polyphenolic tannic acid (TA) on microalgae. Using a block design, lake water samples with and without TA were exposed to solar radiation or kept in darkness with or without bacteria for 3 weeks. Dissolved organic carbon (DOC), specific size fractions of DOC analyzed by chromatography-organic carbon detection (LC-OCD), and concentrations of total phenolic compounds (TPC) were measured to follow the fate of TA in lake water with natural DOC exposed to photolytic and microbial degradation. DOC and TPC decreased in dark-incubated lake water with TA and bacteria indicating microbial degradation. In contrast, exposure to solar radiation of lake water with TA and bacteria did not decrease DOC. Chromatographic analyses documented an accumulation of DOC mean size fraction designated as humic substances (HS) in sunlit water samples with TA. The recalcitrance of the humic fraction indicates that photolytic degradation may contribute to a DOC less available for bacterial degradation. Subsequent growth tests with Desmodesmus armatus (Chodat) E. Hegewald showed low but reproducible difference in algal growth with lower algal growth rate cultured in photolytically and microbially degraded TA in lake water than cultured in respective dark treatments. This finding highlights the importance of photolytic processes and microbial degradation influencing allelopathic effects and may explain the high potential of allelochemicals for structuring the phytoplankton community composition in naturally illuminated surface waters.

  18. Identification and Phytotoxicity Assessment of Phenolic Compounds in Chrysanthemoides monilifera subsp. monilifera (Boneseed).

    Science.gov (United States)

    Al Harun, Md Abdullah Yousuf; Johnson, Joshua; Uddin, Md Nazim; Robinson, Randall W

    2015-01-01

    Chrysanthemoides monilifera subsp. monilifera (boneseed), a weed of national significance in Australia, threatens indigenous species and crop production through allelopathy. We aimed to identify phenolic compounds produced by boneseed and to assess their phytotoxicity on native species. Phenolic compounds in water and methanol extracts, and in decomposed litter-mediated soil leachate were identified using HPLC, and phytotoxicity of identified phenolics was assessed (repeatedly) through a standard germination bioassay on native Isotoma axillaris. The impact of boneseed litter on native Xerochrysum bracteatum was evaluated using field soil in a greenhouse. Collectively, we found the highest quantity of phenolic compounds in boneseed litter followed by leaf, root and stem. Quantity varied with extraction media. The rank of phenolics concentration in boneseed was in the order of ferulic acid > phloridzin > catechin > p-coumaric acid and they inhibited germination of I. axillaris with the rank of ferulic acid > catechin > phloridzin > p-coumaric acid. Synergistic effects were more severe compared to individual phenolics. The litter-mediated soil leachate (collected after15 days) exhibited strong phytotoxicity to I. axillaris despite the level of phenolic compounds in the decomposed leachate being decreased significantly compared with their initial level. This suggests the presence of other unidentified allelochemicals that individually or synergistically contributed to the phytotoxicity. Further, the dose response phytotoxic impacts exhibited by the boneseed litter-mediated soil to native X. bracteatum in a more naturalistic greenhouse experiment might ensure the potential allelopathy of other chemical compounds in the boneseed invasion. The reduction of leaf relative water content and chlorophyll level in X. bracteatum suggest possible mechanisms underpinning plant growth inhibition caused by boneseed litter allelopathy. The presence of a substantial quantity of free

  19. Functional characterization of wheat copalyl diphosphate synthases sheds light on the early evolution of labdane-related diterpenoid metabolism in the cereals.

    Science.gov (United States)

    Wu, Yisheng; Zhou, Ke; Toyomasu, Tomonobu; Sugawara, Chizu; Oku, Madoka; Abe, Shiho; Usui, Masami; Mitsuhashi, Wataru; Chono, Makiko; Chandler, Peter M; Peters, Reuben J

    2012-12-01

    Two of the most agriculturally important cereal crop plants are wheat (Triticum aestivum) and rice (Oryza sativa). Rice has been shown to produce a number of diterpenoid natural products as phytoalexins and/or allelochemicals--specifically, labdane-related diterpenoids, whose biosynthesis proceeds via formation of an eponymous labdadienyl/copalyl diphosphate (CPP) intermediate (e.g., the ent-CPP of gibberellin phytohormone biosynthesis). Similar to rice, wheat encodes a number of CPP synthases (CPS), and the three CPS characterized to date (TaCPS1-3) all have been suggested to produce ent-CPP. However, several of the downstream diterpene synthases will only react with CPP intermediate of normal or syn, but not ent, stereochemistry, as described in the accompanying report. Investigation of additional CPS did not resolve this issue, as the only other functional synthase (TaCPS4) also produced ent-CPP. Chiral product characterization of all the TaCPS then established that TaCPS2 uniquely produces normal, rather than ent-, CPP, thus, providing a suitable substrate source for the downstream diterpene synthases. Notably, TaCPS2 is most homologous to the similarly stereochemically differentiated syn-CPP synthase from rice (OsCPS4), while the non-inducible TaCPS3 and TaCPS4 cluster with the rice OsCPS1 required for gibberellin phytohormone biosynthesis, as well as with a barley (Hordeum vulgare) CPS (HvCPS1) that also is characterized here as similarly producing ent-CPP. These results suggest that diversification of labdane-related diterpenoid metabolism beyond the ancestral gibberellins occurred early in cereal evolution, and included the type of stereochemical variation demonstrated here.

  20. Effects of some sesquiterpenes on the stored-product insect Tenebrio molitor (Coleoptera: Tenebrionidae Efectos de algunos sesquiterpenos sobre el insecto de productos almacenados, Tenebrio molitor (Coleoptera: Tenebrionidae

    Directory of Open Access Journals (Sweden)

    Matías García

    2003-12-01

    Full Text Available In order to evaluate the allelochemical activity of some sesquiterpenes isolated from the native plant Tessaria absinthioides (Hook. et Arn. DC, and some semi synthetic derivatives against Tenebrio molitor L. larvae, we have developed bioassays directed to quantify repellency, larval mortality, and its effects on the development. Although costic aldehyde caused the maximum repellent effect, all the compounds showed a significant effect at some dose or time, indicating behavioral avoidance. The topical application of costic aldehyde produced the largest increase on the duration of the pupal stage. Tessaric acid exhibited the highest toxicity by topical application at the experiment closure. Both eremophilane-1(10,2,11(13-triene-12-oic, and -costic acids induced some morphological deformities.Con el objeto de evaluar sesquiterpenos aislados de la planta nativa Tessaria absinthioides (Hook et Arn y algunos derivados semisintéticos frente a larvas de Tenebrio molitor L., se desarrollaron bioensayos orientados a la cuantificación de la repelencia, mortalidad de larvas y efectos sobre el desarrollo. Aldehído cóstico produjo el mayor incremento en la duración del estado pupal por aplicación tópica. Acido tessárico exhibió el más alto porcentaje de mortalidad al finalizar el período de experimentación. Los productos eremophilan-1(10,2, 11(13-trien-12-oico y ácido -cóstico dieron lugar al mayor número de malformaciones. Si bien aldehído cóstico mostró la máxima actividad de repelencia, todos los compuestos evaluados produjeron efectos significativos en el ensayo de elección.

  1. Glutathione-S-transferase profiles in the emerald ash borer, Agrilus planipennis.

    Science.gov (United States)

    Rajarapu, Swapna Priya; Mittapalli, Omprakash

    2013-05-01

    The emerald ash borer, Agrilus planipennis Fairmaire is a recently discovered invasive insect pest of ash, Fraxinus spp. in North America. Glutathione-S-transferases (GST) are a multifunctional superfamily of enzymes which function in conjugating toxic compounds to less toxic and excretable forms. In this study, we report the molecular characterization and expression patterns of different classes of GST genes in different tissues and developmental stages plus their specific activity. Multiple sequence alignment of all six A. planipennis GSTs (ApGST-E1, ApGST-E2, ApGST-E3, ApGST-O1, ApGST-S1 and ApGST-μ1) revealed conserved features of insect GSTs and a phylogenetic analysis grouped the GSTs within the epsilon, sigma, omega and microsomal classes of GSTs. Real time quantitative PCR was used to study field collected samples. In larval tissues high mRNA levels for ApGST-E1, ApGST-E3 and ApGST-O1 were obtained in the midgut and Malpighian tubules. On the other hand, ApGST-E2 and ApGST-S1 showed high mRNA levels in fat body and ApGST-μ1 showed constitutive levels in all the tissues assayed. During development, mRNA levels for ApGST-E2 were observed to be the highest in feeding instars, ApGST-S1 in prepupal instars; while the others showed constitutive patterns in all the developmental stages examined. At the enzyme level, total GST activity was similar in all the tissues and developmental stages assayed. Results obtained suggest that A. planipennis is potentially primed with GST-driven detoxification to metabolize ash allelochemicals. To our knowledge this study represents the first report of GSTs in A. planipennis and also in the family of wood boring beetles.

  2. Antioxidant genes of the emerald ash borer (Agrilus planipennis): gene characterization and expression profiles.

    Science.gov (United States)

    Rajarapu, Swapna Priya; Mamidala, Praveen; Herms, Daniel A; Bonello, Pierluigi; Mittapalli, Omprakash

    2011-06-01

    Phytophagous insects frequently encounter reactive oxygen species (ROS) from exogenous and endogenous sources. To overcome the effect of ROS, insects have evolved a suite of antioxidant defense genes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GPX). The emerald ash borer (Agrilus planipennis Fairmaire), an exotic invasive insect pest from Asia has killed millions of ash trees and continues to invade North America at a rapid pace. From an on-going expressed sequence tag (EST) project of A. planipennis larval tissues, we identified ESTs coding for a Cu-Zn SOD (ApSOD1), a CAT (ApCAT1) and a GPX (ApGPX1). A multiple sequence alignment of the derived A. planipennis sequences revealed high homology with other insect sequences at the amino acid level. Phylogenetic analysis of ApSOD1 grouped it with Cu-Zn SODs of other insect taxa. Quantitative real time PCR (qRT-PCR) analysis in different larval tissues (midgut, fat body, Malpighian tubule and cuticle) revealed high mRNA levels of ApCAT1 in the midgut. Interestingly, high mRNA levels for both ApSOD1 and ApGPX1 were observed in the Malpighian tubules. Assay of mRNA levels in developmental stages (larva, prepupa and adults) by qRT-PCR indicated high transcript levels of ApCAT1 and ApGPX1 in larval and prepupal stages with a decline in adults. On the other hand, the transcript levels of ApSOD1 were observed to be constitutive in all the developmental stages assayed. Results obtained reflect a plausible role of these A. planipennis antioxidant genes in quenching ROS from both diet (ash allelochemicals) as well as endogenous sources. These studies further help in understanding the adaptation/invasiveness of A. planipennis.

  3. Fish Welfare in Aquaponic Systems: Its Relation to Water Quality with an Emphasis on Feed and Faeces—A Review

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    Hijran Yavuzcan Yildiz

    2017-01-01

    Full Text Available Aquaponics is the combination of aquaculture (fish and hydroponic cultivation of plants. This review examines fish welfare in relation to rearing water quality, fish feed and fish waste and faeces to develop a sustainable aquaponic system where the co-cultured organisms, fish, bacteria in biofilters and plants, should be considered holistically in all aquaponics operations. Water quality parameters are the primary environmental consideration for optimizing aquaponic production and for directly impacting fish welfare/health issues and plant needs. In aquaponic systems, the uptake of nutrients should be maximised for the healthy production of the plant biomass but without neglecting the best welfare conditions for the fish in terms of water quality. Measures to reduce the risks of the introduction or spread of diseases or infection and to increase biosecurity in aquaponics are also important. In addition, the possible impacts of allelochemicals, i.e., chemicals released by the plants, should be taken into account. Moreover, the effect of diet digestibility, faeces particle size and settling ratio on water quality should be carefully considered. As available information is very limited, research should be undertaken to better elucidate the relationship between appropriate levels of minerals needed by plants, and fish metabolism, health and welfare. It remains to be investigated whether and to what extent the concentrations of suspended solids that can be found in aquaponic systems can compromise the health of fish. Water quality, which directly affects fish health and well-being, is the key factor to be considered in all aquaponic systems.

  4. Analysis of phenolic acids and terpenoids in rhizosphere soils of different allelopathic rice varieties under dry field conditions%田间旱育条件下不同化感潜力水稻根际土壤酚酸类和萜类物质分析

    Institute of Scientific and Technical Information of China (English)

    孙小霞; 王海斌; 何海斌; 陆锦池; 林文雄

    2014-01-01

    Although phenolic acids and secondary terpenoid metabolites respectively from shikimate pathway and isoprene metabolic pathway are the main plant allelochemicals, it is far from conclusion in academic circles on what allelochemicals cause rice allelopathy. Thus far, most studies on rice root exudates have been conducted in laboratory conditions. Furthermore, few reports have been made on the changes in allelopathic substances in the rhizoshpere soil of different allelopathic potential rice cultivars especially under stressful field conditions. This paper studied the differences in allelopathic compounds including phenolic acids and terpenoids extracted from the rhizosphere soils of strong allelopathic rice cultivar‘PI312777’ and its counterpart ‘Lemont’ and those from the control soil without any plants under dry and wet soil conditions in the seedling nursery. Putative allelochemicals of rhizosphere soil extracts were then identified via GC-MS (Gas Chromatograph-Mass Spectrometer-computer) and HPLC (High-performance liquid chromatography). The results showed that the compositions of phenolic acids and terpenoid compounds were similar but the contents of them were different in different treated rhizosphere soils and controls. Under moderate drought stress, the total content of five phenolic acids such as caffeic acid, 4-hydroxybenzoic acid, vanillic acid, ferulic acid and cinnamic acid, increased in all treated rhizosphere soils, and allelopathic rice‘PI312777’ showed the highest increases in the total content of the five phenolic acids, which was 2.84 times higher than that of control soil under wet treatment. In addition, among 27 detected and identified terpenoids, 17 were oxygenic monoterpenoid compounds in the extracts of rhizosphere soil samples. Under drought stress, the contents of monoterpenes, oxygenated monoterpenes, oxygenated sesquiterpenes and total terpene showed the changing patterns with different extents and different trends in

  5. Progress of biological invasions research in China over the last decade

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    Chengjen Shih

    2012-09-01

    Full Text Available As one of the five major global environmental problems, invasive species have posed serious threats to native ecosystems, public health, and regional economies. Although much progress has been madein the field of biological invasions research in China over the last decade, there are still large knowledge gaps. This paper reviews progress in the field of biological invasions research since 2000 as it relates to China, covering the diversity, colonization and immigration patterns of invasive species, mechanisms and ecological effects of biological invasions, and management and control of invasive species. In China, 529 invasive alien species have been identified, which originated primarily from South and North America, and the major taxa included terrestrial plants, terrestrial invertebrates, and microorganisms. We found a higher prevalence of invasive species in the eastern and southern provinces, compared to the western and northern provinces in China. This pattern is likely due to the differences in the level of economic development and environmental suitability between the two regions. Moreover, with further economic development, China may face more serious biological invasions in the future. These invasions of alien species are largely the combined results of the interactions between the intrinsic traits of these species along with resource opportunities and disturbances by human beings. Many mechanisms are responsible for successful invasionsof alien species, but phenotypic plasticity, adaptive evolution, enemy release, interspecific mutualism or commensalism, and new allelochemicals may be primary causative factors. Biological invasions in China have caused serious impacts on native ecosystems, including biodiversity and ecosystem services, alteration of biogeochemical cycles, threats to agricultural and forestry production, traffic and shipping, environmental safety, and public facilities. China has also made progress in the detection and

  6. Germinação de sementes e crescimento de plântulas de soja (Glycine max L. Merrill sob cobertura vegetal = Soybean (Glycine max L. Merrill seed germination and plantlet growth under vegetation cover

    Directory of Open Access Journals (Sweden)

    Lúcia Helena Pereira Nóbrega

    2009-07-01

    Full Text Available A eficiência do sistema de rotação de cultura requer, entre outrostratamentos, a escolha adequada das espécies a serem instaladas. Culturas vegetais podem apresentar compostos aleloquímicos, os quais são liberados por meio de pelos radiculares, sementes, raízes, colmos e folhas, em quantidades variáveis, capazes de interferir nas culturas subsequentes, comprometendo a produção. Assim, este estudoanalisou o potencial alelopático de aveia-preta (Avena strigosa Schreb (AP, nabo forrageiro (Raphanus sativus L. (NF, ervilhaca (Vicia sativa L. (ER, azevém (Lolium multiflorum Lam. (AZ e consórcio (CO - AP+ER+NF na germinação de sementes e crescimento de plântulas de soja. O experimento foi em laboratório, com substrato deareia, onde foram cultivadas plantas de cobertura, por 30 dias, mantendo os restos radiculares das plantas com e sem restos de parte aérea. Observou-se redução na emergência de plântulas de soja sob CO, AZ e AP. O índice de velocidade de emergência (IVE, a porcentagem de emergência em areia (EA e a massa fresca de hipocótilo (MFH foram afetados negativamente pelas plantas de cobertura.In order to be efficient, the crop rotation system requires, among other factors, an adequate choice of species to be installed. Vegetalcultures can feature allelochemical compounds, released by root hairs, roots, stems and leaves in variable amounts, which are able to interfere on subsequent cultures, as well as cause a delay in their production. Thus, this study analyzed the allelopathic potentialof black oat (Avena strigosa Schreb (BO, forage turnip (Raphanus sativus L. (FT, vetch (Vicia sativa L. (V, ryegrass (Lolium multiflorum Lam. (RG and consortium (CO - BO+V+FT on soybean seed germination and plantlet growth. This trial was carried out in a laboratory, with sand substrate, where coverage plants were grown, during 30 days. The remaining root portions of plants were kept with and without the remaining aerial part portions

  7. Aspects of the ecology of mat-forming lichens

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    P. D. Crittenden

    2000-03-01

    Full Text Available Lichen species in the genera Cladonia (subgenus Cladina, Cetraria, Stereocaulon and Alectoria are important vegetation components on well-drained terrain and on elevated micro-sites in peatlands in boreal-Arctic regions. These lichens often form closed mats, the component thalli in which grow vertically upwards at the apices and die off in the older basal regions; they are therefore only loosely attached to the underlying soil. This growth habit is relatively unusual in lichens being found in <0.5% of known species. It might facilitate internal nutrienr recycling and higher growth rates and, together with the production of allelochemicals, it might underlie the considerable ecological success of mat-forming lichens; experiments to critically assess the importance of these processes are required. Mat-forming lichens can constitute in excess of 60% of the winter food intake of caribou and reindeer. Accordingly there is a pressing need for data on lichen growth rates, measured as mass increment, in order to help determine the carrying capacity of winter ranges for rhese herbivores and to better predict recovery rates following grazing. Trampling during the snow-free season fragments lichen thalli; mat-forming lichens regenerate very successfully from thallus fragments provided trampling does nor re-occur. Frequent recurrence of trampling creates disturbed habitats from which lichens will rapidly become eliminated consistent with J.P. Grime's CSR strategy theory. Such damage to lichen ground cover has occurred where reindeer or caribou are unable to migrate away from their winter range such as on small islands or where political boundaries have been fenced; it can also occur on summer range that contains a significant lichen component and on winter range where numbers of migrarory animals become excessive. Species of Stereocaulon, and other genera that contain cyanobacteria (most notably Peltigera and Nephroma, are among the principal agents of

  8. The allelopathic effects of invasive plant Solidago canadensis on seed germination and growth of Lactuca sativa enhanced by different types of acid deposition.

    Science.gov (United States)

    Wang, Congyan; Xiao, Hongguang; Zhao, Lulu; Liu, Jun; Wang, Lei; Zhang, Fei; Shi, Yanchun; Du, Daolin

    2016-04-01

    Invasive species can exhibit allelopathic effects on native species. Meanwhile, the types of acid deposition are gradually changing. Thus, the allelopathic effects of invasive species on seed germination and growth of native species may be altered or even enhanced under conditions with diversified acid deposition. This study aims to assess the allelopathic effects (using leaves extracts) of invasive plant Solidago canadensis on seed germination and growth of native species Lactuca sativa treated with five types of acid deposition with different SO4(2-) to NO3(-) ratios (1:0, sulfuric acid; 5:1, sulfuric-rich acid; 1:1, mixed acid; 1:5, nitric-rich acid; 0:1, nitric acid). Solidago canadensis leaf extracts exhibited significantly allelopathic effects on germination index, vigor index, and germination rate index of L. sativa. High concentration of S. canadensis leaf extracts also similarly exhibited significantly allelopathic effects on root length of L. sativa. This may be due to that S. canadensis could release allelochemicals and then trigger allelopathic effects on seed germination and growth of L. sativa. Acid deposition exhibited significantly negative effects on seedling biomass, root length, seedling height, germination index, vigor index, and germination rate index of L. sativa. This may be ascribed to the decreased soil pH values mediated by acid deposition which could produce toxic effects on seedling growth. Sulfuric acid deposition triggered more toxic effects on seedling biomass and vigor index of L. sativa than nitric acid deposition. This may be attributing to the difference in exchange capacity with hydroxyl groups (OH(-)) between SO4(2-) and NO3(-) as well as the fertilizing effects mediated by nitric deposition. All types of acid deposition significantly enhanced the allelopathic effects of S. canadensis on root length, germination index, vigor index, and germination rate index of L. sativa. This may be due to the negatively synergistic effects of

  9. Allelopathic evidence in Brachiaria decumbens and its potential to invade the Brazilian Cerrados

    Directory of Open Access Journals (Sweden)

    Elizabeth Gorgone Barbosa

    2008-08-01

    Full Text Available The aim of this study was to look for evidence of allelochemicals in B. decumbens, in parts of the plant from where they could easily be released to the environment. The germination inhibition of Phalaris canariensis, Lactuca sativa (standard species and Melinis minutiflora, another invasive African grass, was tested using B. decumbens germinating seeds and aqueous leachates of the roots, green and senescent leaves, at 5, 10 and 20% w/v. Both the germinating seeds and the aqueous leachates of B. decumbens reduced the germination of the species tested; the effectiveness of the aqueous leachates increased according to concentration. Apparently, the competitive advantage of B. decumbens in the cerrados could be amplified via allelopathy.Invasão biológica é uma das maiores causas atuais da perda de biodiversidade. Várias espécies que se tornam invasoras produzem substâncias fitotóxicas que aumentam sua capacidade competitiva; assim, a alelopatia é uma estratégia capaz de potencializar o sucesso de invasão. Brachiaria decumbens, uma gramínea africana, invadiu os cerrados brasileiros e representa, atualmente, uma séria ameaça à biota regional. Neste ensaio, verificamos a presença de aleloquímicos em partes de B. decumbens das quais poderiam ser facilmente liberados para o ambiente. Testamos a inibição da germinação de Phalaris canariensis, Lactuca sativa (espécies padrão e Melinis minutiflora (outra gramínea africana invasora usando sementes de B. decumbens e soluções aquosas lixiviadas de suas raízes, folhas verdes e folhas senescentes, a 5, 10 e 20% de peso do material por volume de água. Tanto as sementes como as soluções lixiviadas de decumbens reduziram a germinação das outras espécies; a eficiência dos lixiviados aumentou de acordo com a concentração da solução. Acreditamos que a grande vantagem competitiva de B. decumbens no cerrado possa ser amplificada pela alelopatia.

  10. 空心莲子草不同部位水浸提液对蚕豆、玉米化感作用机制的研究%The Study on Allelopathy Mechanism of Aqueous Extracts from the Different Organizations of Alternanthera philoxeroides Griseb on Vicia faba and Zea mays

    Institute of Scientific and Technical Information of China (English)

    熊勇; 屈睿; 王红斌; 熊开金; 姜传亮

    2011-01-01

    用空心莲子草为研究材料,以农作物蚕豆、玉米为受试植物,采用培养皿滤纸法测定空心莲子草对受试农作物种子萌发率的影响,并检测幼苗的生理指标丙二醛(MDA)含量、超氧化物歧酶(SOD)活性、过氧化物酶(POD)活力以及蚕豆根尖细胞微核率变化,来探讨化感作用机制.结果表明,空心莲子草根、茎、叶不同浓度水浸提液对受试农作物种子萌发率具有不同程度的抑制作用,且处理浓度越高抑制作用越强,水浸提液使受体幼苗体内的MDA含量增加,SOD活性、POD活性先增加后降低趋势,使蚕豆根尖细胞微核率上升.空心莲子草水溶性化感物质使受试农作物受到了氧化胁迫,抗氧化酶系统、蚕豆根尖细胞有丝分裂受到了抑制作用,从而影响了农作物幼苗的萌发和生长.%The study used Alternanthera philoxeroides as material, the subjects plants were Vicia faba and Zea may. The effects of Alternanthera philoxeroides Griseb on the seed germination of two species were studied by using culture dish filter paper method. The physiological index of tested crops MDA content, peroxidase (POD) activity changes, micronucleus rate changes of Vicia faba root-tip cell were detected. The result showed aqueous extracts form Alternanthera philoxeroides Griseb were affected to different degrees for the tested Vicia faba and Zea mays germination rate, made seedlings malondialdehyde (MDA) content to increase, made seedlings superoxide dismutase (SOD) and peroxidase (POD) activity firstly to increase and then to decrease trend, also made root tip cells of Vicia micronucleus rate to increase. The tested crops were oxidative stressed by water-soluble allelochemicals from Alternanthera philoxeroides Griseb. Antioxidant enzyme systems and root tip cells mitosis were inhibited. The aqueous extracts from the different organizations Alternanthera philoxeroides Griseb affected the germination and growth of Vicia faba and

  11. Metabolitos secundários como fontes de bioherbicidas: situação actual e perspectivas Secondary metabolites as sources of bioherbicides: present situation and perspectives

    Directory of Open Access Journals (Sweden)

    L.S. Dias

    2007-01-01

    Full Text Available Metabolitos secundários produzidos e libertados por plantas, bactérias e fungos estão envolvidos numa variedade de processos ecológicos, nomeadamente como semioquímicos e alelopatinos. Adicionalmente, e para além das suas possíveis funções ecológicas, muitos dos metabolitos secundários são fitotóxicos, constituindo uma fonte relativamente inexplorada de novos herbicidas. Solanum nigrum (erva-moira é uma infestante importante e muito bem sucedida num grande número de culturas, nomeadamente hortícolas e será usada como exemplo principal das utilizações actuais de aleloquímicos vegetais bem como das perspectivas de utilização deste tipo de compostos como bioherbicidas. Nesse âmbito revêem-se as principais estratégias de pesquisa de bioherbicidas e apresenta-se o estado da arte dos modos de acção de aleloquímicos já comercializados como herbicidas (Bialaphos e PPT, patenteados (AAL-toxina e em investigação, quer produzidos por plantas superiores (sorgoleona e derivados do cineol quer de origem bacteriana (hidantocidina e fúngica (fumonisinas, coletotriquina.Secondary metabolites produced and released by plants, bacteria, and fungi are involved in a number of ecological processes, namely as semiochemicals and allelopathins. In addition, and beside their possible ecological roles, a greater number of secondary metabolites are phytotoxic and represent a relatively unexplored source of new herbicides. Solanum nigrum (black nightshade is an important and successful weed in many crops, namely in horticulture, and will be used as a major example of actual and prospective uses of phytoallelochemicals as bioherbicides. Therefore, the main strategies for bioherbicides search are reviewed and the state of art of the modes of action of allelochemicals is presented, including those already in use as herbicides (Bialaphos and PPT, patented (AAL-toxin, and under investigation, whether produced by plants (sorgoleone and cineol

  12. Identification, Characterization, and Expression of P450 Gene Encoding CYP6BQ13v2 from the Red Flour Beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

    Institute of Scientific and Technical Information of China (English)

    XU Yong-qiang; WANG Jin-jun; JIANG Hong-bo; DOU Wei; TANG Pei-an; AN Feng-ming

    2009-01-01

    An allele of CYP6BQ13, named CYP6BQ13v2 (GenBank accession no. FJ209361), was isolated from the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) by RT-PCR. The cDNA sequence of CYP6BQ13v2, 1 563 bp in length, contains an open reading frame of 1 554 nucleotides encoding a putative protein of 518 amino acid residues with a predicted molecular weight of 59.92 kDa and a theoretical pI of 7.60. The putative protein contains the classic berne-binding sequence motif F××G×××C×G (residues 456-465) conserved among all P450 enzymes as well as other characteristic motifs of all cytochrome P450s. It shares 98% identity with the previously published sequence of CYP6BQ13 (GenBank accession no. XP_967146) from the T. castaneum genome project. Phylogenetic analysis of amino acid sequences from members of various P450 families indicated that there was closer phylogenetic relationship of CYP6BQ13v2 with CYP302A1 and CYP307A1 mediating synthesis of the insect molting hormone, distant relationship with CYP6B1 metabolizing plant allelochemicals, CYP6D1 linking to pyrethroid resistance and other members of CYP6 family. Expression test of the gene in the adults and immature stages of T. castaneum by quantitative real-time PCR revealed that CYP6BQ13v2 is expressed in all life stages investigated. The mRNA expression level in 1st instar larvae was 14.9-and 3.86-fold higher than those in pupae and adults, respectively. The CYP6BQ13v2 expression levels appeared in the order of 1st instar larvae, followed by 4th instar larvae, 7th instar larvae, adult, and pupae from high to low. The more bioinformation of CYP6BQ13v2 was also analyzed.

  13. Study on the mechanism of allelopathic influence on cyanobacteria and chlorophytes by submerged macrophyte (Myriophyllum spicatum) and its secretion

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Junying [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Liu Biyun [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Wang Jing; Gao Yunni [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Wu Zhenbin, E-mail: wuzb@ihb.ac.cn [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China)

    2010-06-10

    For revealing the mechanism of allelopathic influence on phytoplankton by aquatic macrophytes, the growth and photosynthetic activities of cyanobacteria Microcystis aeruginosa and the chlorophyte Selenastrum capricornutum were investigated when they coexisted with submerged macrophyte Myriophyllum spicatum and were exposed to allelopathic polyphenols: pyrogallic acid (PA), gallic acid (GA), ellagic acid (EA) and (+)-catechin (CA). According to the results of coexistence assays, the non-photochemical quenching (NPQ) and effective quantum efficiency (YII) of M. aeruginosa were affected earlier and more rapidly than the cell density. However, the influence of M. spicatum on S. capricornutum was not found. When the Toxicity Index (TI) was applied to evaluate the combined effects of binary and multiple mixtures of polyphenols, it was found that the four tested polyphenols with the proportion identified in the M. spicatum-cultured solution were observed to present synergistic effect (0.36-0.49) according to the cell density, NPQ and YII of M. aeruginosa. With the combined effects of polyphenols on S. capricornutum, only additive action (0.52-1.62) was found. On the other hand, PA (2.97 mg L{sup -1}), GA (2.65 mg L{sup -1}) caused significant reductions of photosystem II (PSII) and whole electron transport chain activities of M. aeruginosa by 71.43 and 18.37%, 70.95 and 40.77% (P < 0.05), respectively, after 24-h exposure, but no inhibition effect was found in S. capricornutum. The dark respiration and photosystem I (PSI) activities of M. aeruginosa were significantly increased by exposure to PA and GA (P < 0.05). Nevertheless, EA and CA had no influence on the electron transport activities of the tested organisms. These results indicate that the reduction in photosynthetic activity of M. aeruginosa and the synergistic effect of allelochemicals may be two important causes for the inhibition of undesired phytoplankton by submersed macrophytes in natural aquatic ecosystems

  14. Growth inhibition of cultured marine phytoplankton by toxic algal-derived polyunsaturated aldehydes.

    Science.gov (United States)

    Ribalet, François; Berges, John A; Ianora, Adrianna; Casotti, Raffaella

    2007-12-15

    . Concentrations used are in a significant range for affecting growth and performance of phytoplankton living in close vicinity of PUA-producing algae. Thus, PUAs may act as allelochemicals by mediating interactions among planktonic organisms.

  15. Potencial alelopático de Ipomoea fistulosa sobre a germinação de alface e tomate = Allelopathic potential of Ipomoea fistulosa on the germination of lettuce and tomato

    Directory of Open Access Journals (Sweden)

    Juliana Domingues Lima

    2008-07-01

    Full Text Available O objetivo do presente trabalho foi determinar o potencial alelopático de Ipomoea fistulosa na germinação e crescimento de plântulas. Em laboratório, sementes de alface e de tomate foram colocadas para germinar na presença de água ou extratos de folhasde Ipomoea fistulosa, nas concentrações de 5, 10 e 15% (p/v. Em casa-de-vegetação, as sementes foram colocadas para germinar em bandejas, contendo o substrato Plantmax® e o substrato Plantmax® + resíduo de folhas secas de Ipomoea fistulosa, na proporção 3% (p/p. Oextrato aquoso inibiu a germinação e elevou o tempo médio de germinação das sementes, além de reduzir o crescimento da radícula e hipocótilo em todas as concentrações utilizadas. Em casa-de-vegetação, a altura da planta, o número de folhas, o acúmulo de massa seca das plantas também foram reduzidos na presença dos resíduos de folhas no substrato. Os resultados sugerem a presença de aleloquímicos em Ipomoea fistulosa e demonstram maior sensibilidade da alface a esses compostos, quando comparada ao tomate.The objective of the present research was to determine theallelopathic potential of Ipomoea fistulosa plants on germination and growth of seedlings. In laboratory, lettuce and tomato seeds were placed to germinate in the presence of water or Ipomoea fistulosa leaf extract, in the concentrations of 5, 10 e 15% (p/v. In greenhouse, seeds were placed to germinate in trays containing Plantmax® substrate and Plantmax® substrate + Ipomoea fistulosa dry leaf residue, at 3% (w/w. The aqueous extract inhibited germination,raised the mean germination time of the seeds and reduced the radicle and hypocotyl growth in all used concentrations. In greenhouse, the plant height, leaf number, and dry mass accumulation also were reduced in the presence of the leaf residue in the substrate.The results suggest the presence of allelochemicals in Ipomoea fistulosa and demonstrate the highest sensitivity of lettuce that tomato

  16. Studies on the Allelopathy and GAP Management of Andrographis paniculata (Burm.f.) Nees%穿心莲化感作用与GAP栽培规范的研究

    Institute of Scientific and Technical Information of China (English)

    曾令杰; 刘意; 褚晨亮; 何洋

    2011-01-01

    目的 研究穿心莲的化感作用,为GAP栽培管理提供依据.方法 以表面皿培养法试验穿心莲根际土壤浸提液及穿心莲内酯对照品溶液对穿心莲种子及三叶鬼针草种子萌发的抑制作用:以HPLC法对穿心莲根际土壤浸提液进行了分析鉴定.结果 穿心莲根际土壤浸提液及穿心莲内酯对照品溶液均能显著抑制三叶鬼针草和穿心莲种子的萌发,其抑制作用随着浓度的增大而增强;结果表明,穿心莲内酯是其根际土壤浸提液中的一主要成分.结论 穿心莲在其生长过程中释放了化感物质进入了其根际土壤,对穿心莲和其他植物产生化感作用,穿心莲内酯为其中的主要化感物质之一.%Objective To investigate allelopathy of Andrographis paniculata (Burm.f.) Nees for its GAP management.Methods With watch glass culture, the inhibitory effects of andrographlide and the rhizosphere extract of Andrographis paniculata on seed germination of the herb itself and Bidens pilosa were conducted, and with HPLC method, the main constituents of the rhizosphere extract were analysed.Results The results showed that both of andrographlide and the rhizosphere extract had significant inhibitory effects on the germinations of Bidens pilosa seeds and itself; the effects strengthened with increasing of their concentrations.Andrographlide is one kind of main constituents in the rhizosphere extract indicated by HPLC analysis.Conclusion In the growth period, Andrographis paniculata release some alleochemicals into the soil, and andrographlide is one of the main allelochemical.

  17. Allelopathy of plants in space

    Science.gov (United States)

    Tomita-Yokotani, K.; Baba, K.; Fujii, Y.; Hashimoto, H.; Nakamura, T.; Yamashita, M.

    Allelopathy is a chemical way of interaction among many organisms living together on the earth, and forming ecological systems as the member of the biosphere. Biosynthesis of allelochemicals, their release, transport and sensing mechanism at the recipient organisms, which is associated with allelopathy, are under the influence of gravity in many aspects. Such gravitational action on the allelopathy could be ranged from perturbation on biochemical networks in the cells to macroscopic transportation phenomena around the organisms. If gravity is an environmental factor that governs those processes, allelopathy at the absence of gravity on space craft, or under the different magnitude of gravity on the outer planets might differ from allelopathy on the ground. Another important factor in allelopathy in space application is physical closure of living environment, and lack of natural process to decompose allelopathic chemicals or the sink among material circulation in the biosphere. Many organisms and ecological system may behave differently in spacecrafts or on outer planets, based on the modified inter-organisms and -species interactions associated with alleopahty. In order to examine allelopathy under exotic gravity and closed environment, we imposed pseudo-microgravity and physical closure on a plant-plant allelopathy system. Two plant species were co-cultured in a closed vessel, and gravity vector was randomized by the 3D-clinorotation. Velvet bean (Mucuna pruriens L.) is known to induce strong allelopathic action on many plant species. Velvet bean and lettuce was chosen as the pair. Growth of lettuce seedlings, co-cultured with velvet bean, was analyzed under the 3D-clinorotation, and compared it with growth of the ground control group. The degree of allelopathic suppression on the lettuce root growth was less on the 3D-clinorotation. L-DOPA (L-3,4-dihydroxy-phennylalanine), released from root is the major substance responsible to the allelopathy of velvet bean

  18. Allelopathy effect of rice straw on the germination and growth of Echinochloa crus-galli (L.) P. Beauv

    Science.gov (United States)

    Anuar, Fitryana Dewi Khairul; Ismail B., S.; Ahmad, Wan Juliana Wan

    2015-09-01

    to be conducted to determine the mode of action of the allelochemicals involved in rice allelopathy.

  19. Cross-resistance to alpha-cypermethrin after xanthotoxin ingestion in Helicoverpa zea (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Li, X; Zangerl, A R; Schuler, M A; Berenbaum, M R

    2000-02-01

    Cytochrome P450 monooxygenases (P450) are membrane-bound hemoproteins that play important roles in conferring protection against both naturally occurring phytochemicals and synthetic organic insecticides. Despite the potential for common modes of detoxification, cross-resistance between phytochemicals and synthetic organic insecticides has rarely been documented. In this study, we examined the responses of a susceptible strain of corn earworm, Helicoverpa zea (Boddie), a polyphagous noctuid, to exposure by an allelochemical infrequently encountered in its host plants and by an insecticide widely used for control purposes. Within a single generation, survivors of xanthotoxin exposure displayed higher levels of tolerance to alpha-cypermethrin than did unexposed control larvae. The F1 offspring of xanthotoxin-exposed survivors also displayed higher alpha-cypermethrin tolerance than did offspring of unexposed control larvae, suggesting that increased alpha-cypermethrin tolerance after xanthotoxin exposure represents, at least in part, heritable resistance. Administration of piperonyl butoxide, a P450 synergist, demonstrated that resistance to both xanthotoxin and alpha-cypermethrin is P450-mediated. Alpha-cypermethrin-exposed survivors, however, failed to show superior growth on xanthotoxin diets. Assays with control larvae, larvae induced by both xanthotoxin and alpha-cypermethrin, and survivors of LD50 doses of both compounds indicated that H. zea midgut P450s are capable of metabolizing both xanthotoxin and alpha-cypermethrin. Metabolism of each compound is significantly inhibited by the presence of the other compound, suggesting that at least one form of P450 in H. zea midguts degrades both compounds and may constitute the biochemical basis for possible cross-resistance. Compared with control larvae, xanthotoxin- and alpha-cypermethrin-induced larvae displayed 2- to 4-fold higher P450-mediated metabolism of both compounds. However, xanthotoxin- and alpha

  20. 韭菜水提液对3种蔬菜种子的化感作用%Allelopathy Efects of Water Extract from Allium tuberosum on Vegetable Seeds

    Institute of Scientific and Technical Information of China (English)

    江贵波; 陈少雄; 江晓玲; 杨银娇; 聂耀龙; 蔡玉玲

    2014-01-01

    为解决生产实践中的连作障碍问题,以韭菜(Allium tuberosum Rottler.ex Spreng.)为供体,以其地上部分的水提液为化感物质,分别以白菜(Brassica chinensis L.)、油菜(Brassica campestris L.)和萝卜(Raphanus sativus L.)种子为受体,采用培养皿滤纸法进行化感试验,测定韭菜的茎叶水提液对油菜、白菜和萝卜幼苗的根长、苗高和鲜重的影响。结果表明:韭菜的地上部分的水提液对油菜、白菜和萝卜种子的萌发及其幼苗生长有明显的化感作用,且不同浓度水提液对蔬菜幼苗生长的影响存在差异,浓度为0.50 g/mL时抑制作用最强。%In order to solve the problem of continuous cropping barrier in production practice,taking Allium tuberosum as the donor,water extract of its aerial parts as allelochemicals and Brassica chinensis , Brassica campestris and Raphanus sativus seeds as the receptor,the effects of water extract of A.tuberosum on root length, seedling height and fresh weight of B.chinensis,B.campestris and R.sativus were studied by filter paper method with culture dish.Results:aerial part water extract had significant allelopathy on seed germination and seedling growth.Difference was observed among different concentrations of water extract (0.10 g/mL,0.25 g/mL,0.50 g/mL).0.5 g/mL had the strongest inhibition effect.Root length of rape seedling of 0.10 g/mL,0.25 g/mL and 0.50 g/mL treatments was reduced by 98.3%,100.0% and 100.0% respectively compared with the control.And that of B.chinensis seedling was reduced by 97.1%,100.0% and 100.0% respectively,and R.sativus was reduced by 72.5%,91.2% and 98.7% separately.

  1. CYP99A3: Functional identification of a diterpene oxidase from the momilactone biosynthetic gene cluster in rice

    Science.gov (United States)

    Wang, Qiang; Hillwig, Matthew L.; Peters, Reuben J.

    2013-01-01

    SUMMARY Rice (Oryza sativa) produces momilactone diterpenoids as both phytoalexins and allelochemicals. Strikingly, the rice genome contains a biosynthetic gene cluster for momilactone production, located on rice chromosome 4, which contains two cytochromes P450 mono-oxygenases, CYP99A2 and CYP99A3, with undefined roles; although it has been previously shown that RNAi double knock-down of this pair of closely related CYP reduced momilactone accumulation. Here we attempted biochemical characterization of CYP99A2 and CYP99A3, which ultimately was achieved by complete gene recoding, enabling functional recombinant expression in bacteria. With these synthetic gene constructs it was possible to demonstrate that, while CYP99A2 does not exhibit significant activity with diterpene substrates, CYP99A3 catalyzes consecutive oxidations of the C19 methyl group of the momilactone precursor syn-pimara-7,15-diene to form, sequentially, syn-pimaradien-19-ol, syn-pimaradien-19-al and syn-pimaradien-19-oic acid. These are presumably intermediates in momilactone biosynthesis, as a C19 carboxylic acid moiety is required for formation of the core 19,6-γ-lactone ring structure. We further were able to detect syn-pimaradien-19-oic acid in rice plants, which indicates physiological relevance for the observed activity of CYP99A3. In addition, we found that CYP99A3 also oxidized syn-stemod-13(17)-ene at C19 to produce, sequentially, syn-stemoden-19-ol, syn-stemoden-19-al and syn-stemoden-19-oic acid, albeit with lower catalytic efficiency than with syn-pimaradiene. Although the CYP99A3 syn-stemodene derived products were not detected in planta, these results nevertheless provide a hint at the currently unknown metabolic fate of this diterpene in rice. Regardless of any wider role, our results strongly indicate that CYP99A3 acts as a multifunctional diterpene oxidase in momilactone biosynthesis. PMID:21175892

  2. Papel dos tricomas glandulares da folha do tomateiro na oviposição de Tuta absoluta Role of tomato leaf glandular trichomes on oviposition of Tuta absoluta

    Directory of Open Access Journals (Sweden)

    Elsa Gilardón

    2001-03-01

    Full Text Available Os tricomas glandulares presentes nas folhas e ramos das plantas do gênero Lycopersicon são responsáveis pela secreção de metabólitos de diferentes naturezas. A presença de alguns desses compostos tem sido associada à resistência do tomate a diferentes insetos. A traça-do-tomateiro, Tuta absoluta (Meyrick, é uma das pragas mais nocivas da América do Sul. O adulto oviposita sobre as folhas do tomate e suas larvas abrem galerias no mesófilo das folhas, ramos, flores e frutos. As espécies silvestres do tomate conservam a capacidade de biossintetizar compostos químicos que lhes conferem resistência a esta praga. No presente trabalho, foi avaliada a preferência para oviposição desse inseto sobre folhas com e sem tricomas glandulares de L. esculentum (Mill. cv. Uco Plata, suscetível, e de L. hirsutum f. glabratum (Mull. PI 134417, espécie silvestre afim ao tomate, e resistente à traça. Os resultados sugerem que as fêmeas ovipositam indistintamente sobre as folhas de ambas espécies, independentemente da presença, ou não, dos tricomas glandulares. E a presença destes e de seus exsudatos não têm efeito inibidor na oviposição do inseto.In the genus Lycopersicon, different metabolites are secreted by the glandular trichomes of leaves and stems. These compounds have been associated to different tomato pests resistance. The South American tomato pinworm, Tuta absoluta (Meyrick, is one of the most harmful pests in South America. The females oviposit on tomato leaves and the larvae mine the leaf mesophyl, stems, flowers and fruits. Some wild accessions of Lycopersicon keep their capacity to synthesize allelochemicals that protect them from the pest. In this paper a comparison was made between the tomato pinworm oviposition on leaves with and without trichomes of L. esculentum (Mill. cv. Uco Plata, a susceptible cultivar, and L. hirsutum f. glabratum (Mull. PI 134417, a resistant wild accession. Results suggest that the female

  3. 植物体中萜类物质化感作用的研究进展%Advances of research on allelopathic potencial of terpenoids in plants

    Institute of Scientific and Technical Information of China (English)

    张秋菊; 张爱华; 孙晶波; 张连学

    2012-01-01

    Terpenoids widely exist in higher plants as volatile oil, especially in Compositae family. They have the largest variety of plant secondary metabolization products and are classified into monoterpene, diterpene, sesquiterpene, triterpene and polyterpene according to their structures. Terpenoids are one of the main types of allelochemicals, of which monoterpene and sesquiterpene have stronger bioactivities. The synthesized terpenids are mainly released from plants into soil through volatilization or root exudation and disturb the growth and development of neighboring plants and selfish. Currently, the allelopathy on terpenoids had received increased attention in plant ecology field in China and abroad. This paper made a systematic discussion on the distribution of trpenoids, accumulation characteristic, releasing pathways in plants and its impact factors, etc. And it analyzed the allelopathic mechanism of trpenoids and summarized the research progress in this area in recent years. The paper considered that the trpenoids played a special role on allelopathic activity and exhibited a stronger inhibitory even though the concentration was lower. The complicated allelopathy of terpenoids may be due to their wide varieties. Moreover, many factors all influenced the releasing of terpenoids. Finally, the paper pointed out some key problems in current researches and also made a prospect for the research trends in the future on the allelopathy of terpenoids. It is suggested that further study should be focused on the collecting method of terpenoid allelochemicals and the influences of transformed medium such as soil or air on allelopathic activity. In addition, it is effective and feasible to study allelopathic mechanism of terpenoids through the solution of discipline-crossing.%萜类物质主要以挥发油的形式广泛存在于高等植物中,尤以菊科植物含量丰富.萜类是天然物质中种类最多的一类,按结构可分为单萜、双萜、倍半萜、三

  4. Relationship between potato continuous cropping obstacle and soil environmental factors%马铃薯连作障碍与土壤环境因子变化相关研究

    Institute of Scientific and Technical Information of China (English)

    徐雪风; 回振龙; 李自龙; 张俊莲; 李朝周

    2015-01-01

    This study aims to investigate the effect of potato continuous cropping on soil properties ,thus clarifying factors contributing to continuous cropping obstacles ,using pot culture experiments .We analyzed soil properties includ-ing microbiological compositions ,fertility ,physicochemical properties and contents of phenolic acid and allelochemicals of potato continuous cropping soil ,and performance of potato seedlings .The results indicated that soil salinity ,alkaline hydrolysis nitrogen content and soil bulk density increased ,as the continuous cropping prolonged .Activities of urease , catalase ,alkaline phosphatase and invertase decreased markedly when continuous cropping lasted for 5 and 7 years ,while the quantity of soil’s bacteria and actinomycetes decreased .The content of chlorophyll ,activities of antioxidase ,root ac-tivity and net photosynthetic rate decreased significantly when the continuous cropping lasted for 5 and 7 years .As a whole ,continuous cropping obstacle was not obvious when continuous cropping lasted for 3 years .But potato continuously cropping lasted for 5 and 7 years ,a series of biotic and abiotic stresses were triggered due to increasing of compositions of soil fungi ,and the activity of key enzyme ,the changes of physicochemical properties ,and phenolic acid and allelochemi-cals contents ,resulting in continuous cropping obstacle .%取不同连作年限(连作0、3、5、7年)的土壤测定其生物和非生物环境因子,并采用盆栽的方法获取不同连作年限的马铃薯幼苗,测定其生长发育指标及抗性生理指标,以探究马铃薯不同连作年限土壤生物和非生物环境因子的变化。结果表明:随着连作年限的增加,土壤含盐量、碱解氮含量和土壤容重逐年上升,在连作7年时分别比对照高348.31%、228.57%和5.39%;在连作5年和7年时,速效磷、速效钾和有机质含量显著下降,连作7年时比对照下降27.43

  5. The Changes and Degradation of Tobacco Root Exudates in Tobacco Field with Continuous Cropping%连作烟田土壤根系分泌物的变化和分解

    Institute of Scientific and Technical Information of China (English)

    于会泳; 申国明; 高欣欣

    2014-01-01

    We analyzed contents of tobacco root exudates in 0-20 cm and 20-40 cm soil where tobacco had grown for 1 year, 2 years, and 3 years in order to investigate variation of exudates in tobacco field and identify allelochemicals. The results showed that the content of benzoic acid, 4-hydroxyphenylacetic acid, 3-oxygen-4-hydroxyphenylacetic acid and phthalic acid dioctyl ester in tobacco field were high, of which 4-hydroxyphenylacetic acid was the highest, and the content of 4-hydroxybutyric acid and glycerin were low. Hydroxybutyric acid, 3-methyl-2-hydroxy butyric acid, 4-hydroxybutyric acid, cinnamic acid, oleic acid, stearic acid amide and nicotine had no direct allelopathic influence to tobacco. The decomposition rates of cinnamic acid, 3-methoxy-4-hydroxyphenyl acetic acid, phthalic acid, 3-hydroxy benzoic acid, dioctyl phthalate, 4-hydroxyphenyl acetic acid and myristic acid were less than 50%. We proposed that the following acids were allelochemicals, including benzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, lauric acid, oterephthalic acid, 3-methoxy-4-hydroxyphenyl acetic acid, 3,4-dihydroxybenzoic acid, myristic acid, palmitic acid, 9,12-octadecadienoic acid, acrylic acid, scopoletin, cinnamic acid, phthalic acid dioctyl phthalate and 4-hydroxyphenylacetic acid.%为阐明烟田土壤中根系分泌物的变化规律及确定具有化感作用的根系分泌物种类,研究分析了种烟1年、连作2年和连作3年0~20 cm、20~40 cm烟田土壤中根系分泌物的含量变化,并通过室内试验研究了烟草根系分泌物的分解转化。结果表明:(1)烟田土壤中含量较高的根系分泌物种类有苯甲酸、4-羟基苯乙酸、3-甲氧基-4-羟基苯乙酸和邻苯二甲酸二辛酯,其中4-羟基苯乙酸含量最高,含量较低的种类有4-羟基丁酸和甘油;(2)羟基丁酸、3-甲基-2-羟基丁酸、4-羟基丁酸、肉桂酸、油酸、硬脂酸酰胺和烟碱对烟草无直接化感作用;(3)

  6. Seleção para alto teor de acilaçúcares em genótipos de tomateiro e sua relação com a resistência ao ácaro vermelho (Tetranychus evansi e à traça (Tuta absoluta Selection towards high acylsugar levels in tomato genotypes and its relationship with resistance to spider mite (Tetranychus evansi and to the South American pinworm (Tuta absoluta

    Directory of Open Access Journals (Sweden)

    Guilherme Victor Nippes Pereira

    2008-06-01

    Full Text Available Uma das estratégias do melhoramento do tomateiro, no Brasil, visando à resistência a pragas, tem sido a utilização de aleloquímicos presentes nos folíolos. Objetivou-se no presente trabalho, estudar os níveis de resistência a dois artrópodos-pragas [traça do tomateiro (Tuta absoluta e ácaros (Tetranychus evansi], em genótipos previamente selecionados com base apenas no seu teor foliar de acilaçúcares. Foram selecionadas 11 plantas contrastantes quanto aos níveis de acilaçúcares nos folíolos, de uma população F3RC2, derivada do cruzamento interespecífico Lycopersicon esculentum Mill 'TOM-584' x Lycopersicon pennellii (Correll D'Arcy 'LA-716'. Esses genótipos, juntamente com os genitores TOM-584 e LA-716, foram submetidos a ensaios de repelência/resistência a artrópodos-pragas. No teste de repelência ao ácaro T. evansi, as plantas com altos teores de acilaçúcares se comportaram de forma semelhante ao genitor resistente LA-716. As magnitudes das correlações foram negativas e significativas, confirmando assim a associação entre altos teores do aleloquímico e a resistência (repelência ao ácaro, avaliada pela distância percorrida. No ensaio realizado com a traça do tomateiro, os genótipos foram avaliados para danos nas plantas e lesões nos folíolos. Os genótipos contendo alto teor de acilaçúcares, demonstraram bons níveis de resistência a Tuta absoluta, não diferindo significativamente do acesso selvagem LA-716. Em todas as épocas de avaliação, os teores de acilaçúcares mostraram-se alta e negativamente correlacionados com os níveis de dano causados pela traça. Os resultados obtidos comprovaram a eficiência da seleção de genótipos de tomateiro com elevados teores de acilaçúcares nos folíolos, visando à resistência a artrópodos-praga.Selection for high foliar levels of allelochemicals has been proposed as a suitable strategy for breeding tomatoes for arthropod pest resistance. In the

  7. Responses of Lactuca sativa and Festuca arundinacea to the allelopathy of water extracts from Jacaranda mimosifolia flowers%莴苣与高羊茅对蓝花楹花水浸液化感作用的响应

    Institute of Scientific and Technical Information of China (English)

    李青; 石锦安; 刘月婷; 孙莹; 邵小鹏

    2015-01-01

    In order to verify whether there are relevant substances in J acaranda mimosifolia that can produce the al-lelopathy to other plants.We studied the allelopathy of the concentration of 0.001,0.025,0.050 g·mL-1 water ex-tract of the flowers of J .mimosifolia for the seed germination and seedling growth,taking the complete single flow-ers of J .mimosifolia grown in Wenjiang region as materials,the seeds of Lactuca sativa and Festuca arundinacea as receptor materials,and the water treatment as the control CK .The results were as follows:firstly,the seed germi-nation of F .arundinacea and Lactuca sativa was suppressed by the water extract,especially performance on the ger-mination index,and the comprehensive allelopathies (SE 2 )were-0.13 and-0.27 respectively;secondly,the seedling height of L .sativa was promoted but its root length and root-shoot ratio were suppressed,and the values of SE 3 ,SE 4 ,SE 5 were 0.13,-0.36,-0.16,while the root-shoot ratio of Festuca arundinacea were promoted but its seedling height and root length were suppressed,and the values of SE 3 ,SE 4 ,SE 5 were-0.12,-0.08,0.16 respectively.Mean-while the MDA contents and root vigor of Lactuca sativa were also suppressed,whose values of SE 6 and SE 7 were-0.25 and-0.44,the values of Festuca arundinacea were 0.04 and 0.34 reversely.Most of all,when the concentration of the water extracts was 0.025 g·mL-1 ,it showed the RI peak and inflection point of some trend in many places, especially the changes in MDA contents and root vigor of receiver plant’s leaves.Thus,the experiment proved the existence of allelochemicals in water extract of J acaranda mimosifolia flowers,Lactuca sativa and Festuca arundi-nacea ,and they had different responses to the allelochemicals,which will provide the relevant theoretical basis to the plant landscape design and maintenance of J acaranda mimosifolia in the future.%为探明蓝花楹是否存在对其它植物产生化感作用的相关物质,以生长在四川温

  8. Biodiversity of understory vegetation in different-aged Manchurian walnut plantations%不同林龄胡桃楸林下植物多样性的差异

    Institute of Scientific and Technical Information of China (English)

    杨立学; 孙跃志

    2013-01-01

    Taking 16-, 23-, and 51 years old Manchurian walnut (Juglans mandshurica) plantations at Maoershan of Heilongjiang Province, Northeast China as test objects, and with the consideration of allelochemicals, this paper studied the differences in the understory vegetation biodiversity among the plantations. With the increasing age of the plantations, the understory shrub richness index (IMa) , diversity index (Isw) , and Pielou evenness index (J) all presented an increasing trend, while the understory herb IMa and Isw were decreasing, and the herb species number decreased from 14 to 10. The most important plant species in the different-aged plantations were Rubus kanayamensis, Erigeron annuus, Taraxacum officinale, and Potentilla centigrana in 16 years old plantation, Ulmus japonica, Syringare ticulata, and Diarrhena manshurica in 23 years old plantation, and Syringare ticulata, Hippochaete hiemale, and Brachybotrys paridiformis in 51 years old plantation. The plant biodiversity of the plantations was less affected by juglone, but the understory shrub biodiversity was more affected by soil available P and K. The understory shrubs and herbs adapted differently to various soil pH ranges. Other soil factors such as bulk density, moisture content, organic matter, and total N had opposite effects on the biodiversity of understory shrubs and herbs.%以黑龙江省帽儿山地区不同林龄胡桃楸(Juglans mandshurica)人工林为对象,在考虑化感物质影响的基础上,研究了不同林龄林分植物多样性的差异.结果表明:随着胡桃楸林龄的增加,林下灌木丰富度指数(IMa)、多样性指数(Isw)及Pielou均匀度指数(J)均呈现递增趋势;林下草本,除均匀度指数外,其他2个指数随着林龄的增长呈递减趋势;随着胡桃楸年龄的增加,草本种类由14种逐渐减少到10种;16年生的胡桃楸林分重要值较大的物种有蔷薇科的山楂叶悬钩子,菊科的一年蓬、蒲公英和

  9. Efeito alelopático de sabugueiro e capim-limão na germinação de picão-preto e soja = Allelophatic effect of Sambucus australis Cham. and Schltdl. and Cymbopogon citratus (DC Stapf. in the germination of Bidens pilosa L. and soybeans

    Directory of Open Access Journals (Sweden)

    Andréa Maria Teixeira Fortes

    2009-04-01

    Full Text Available As plantas invasoras são constantes e diminuem a produtividade das culturas por competirem por espaço, nutrientes e água. Dessa forma, os agricultores adotam, em grande escala, produtos químicos eficientes no controle da lavoura e com alta toxicidade ao meioambiente. Existem, no entanto, formas alternativas para o controle de invasoras, por meio de aleloquímicos presentes em algumas plantas, dentre elas, as medicinais. Este trabalho tem como objetivo analisar as propriedades alelopáticas dos extratos das plantas medicinais Cymbopogon citratus (DC Stapf. e Sambucus australis Cham. and Schltdl. em inibir a germinação de Bidens pilosa L., sem interferir na germinação de Glycine max L. Merrill. Os extratos foram obtidos triturandose 200 g de folhas com 1 L de água destilada. As sementes foram mantidas em B.O.D. à temperatura de 25°C, com fotoperíodo de 12h de luz. Nas condições em que foram realizados os experimentos, constatou-se que o extrato de capim-limão inibiu a germinação de picão-preto sem que este inibisse a germinação da soja, enquanto o extrato de sabugueiro inibiu a germinação de picão-preto e a germinação da soja. Assim, indica-se a utilização do capim-limão, como um herbicida natural para o picão-preto.Agriculture has been suffering adaptations throughout time, from hard hand labor to the most advanced sowing and harvesting techniques. Invasive plants are a constant, diminishing productivity by competing for space, nutrients, and water. Therefore, farmers have adopted, on alarge scale, the use of efficient synthetic chemicals, which are highly toxic to the environment, in order to control plant production. However, there are other alternative means to control those competitors: using allelochemicals present in some plants, such as medicinal ones. The objective of this paper is to analyze allelophatic properties of the medicinal plants Cymbopogon citratus (DC Stapf. and Sambucus australis Cham. and Schltdl

  10. Estudo fitoquímico de Senna alata por duas metodologias Phytochemical study of Senna alata using two methodologies

    Directory of Open Access Journals (Sweden)

    I.M.C. Rodrigues

    2009-01-01

    determine the main classes of potential allelochemicals of different fractions (stems, flowers, leaves, roots, seeds and pods of S. alata. The plant material was dried and submitted to exhaustive extraction with hydromethanolic solvent to obtain the crude extracts, with a small part being solubilized in methanol to obtain the test solutions. The following methods were used: thin-layer chromatography (TLC, to determine the qualitative chromatographic profile, and preliminary detection tests of the distinct chemical constituents, based on their extraction with appropriate solvents and application of color testing. The results of both methods showed few similarities, with the TLC being the simplest, most inexpensive, fastest, and most appropriate for preliminary analysis of plant-derived chemical compounds, despite being a qualitative method. This method was more sensitive for flavonoid detection, although the Bouchardat reactive was more sensitive to alkaloid detection than the Dragendorff. Ammonium hydroxide 10% was more sensitive to anthraquinones than Potassium hydroxide. The study showed the high diversity of the chemical compounds present in Senna alata, justifying its extensive use in popular medicine and even indicating its potential allelopathic use.

  11. Allelopathic activity of micropropagated Hyssopus officinalis L., Lamiaceae, water infusions Atividade alelopática de micropropagado Hyssopus officinalis L. infusãos aquosos

    Directory of Open Access Journals (Sweden)

    Asya P. Dragoeva

    2010-09-01

    Full Text Available The natural habitats of Hyssopus officinalis L. (Lamiaceae in Bulgaria are not sufficient to satisfy the needs of this herb. Micropropagation might be used for obtaining plants with desirable traits. Hyssopus is a medicinal aromatic plant that has not been studied very much. Recently aromatic plants were investigated as potent allelopathic plants. Determining the modes of action of allelochemicals is one of the challenging aspects in allelopathic studies. The objective of this study was to determine the allelopathic activity of micropropagated Hyssopus officinalis L. water infusions. We evaluated the influence of hot and cold infusions made from the aerial parts of hyssopus under laboratory conditions. For this purpose we tested the effects of infusions on germination and root elongation of Cucumis sativus L. and Triticum aestivum L. We determined also the effect on mitotic activity using Allium cepa L. chromosome aberration test. The results demonstrated the presence of water soluble allelopathic compounds in hyssopus tissue. Infusions exhibited growth depressive effect which was stronger at early stage of growth. The inhibitory effects on germination and root elongation were stronger in T. aestivum than in C. sativus. Hyssopus also exerted mitodepressive and genotoxic effect in Allium cepa root tip cells.Os hábitats naturais de Hyssopus officinalis L. (Lamiaceae na Bulgária não são suficientes para satisfazer as necessidades desta erva. A micropropagação poderia ser usada para obter plantas com características desejáveis. Hyssopus é uma planta aromática medicinal que não foi estudada muito. Recentemente plantas aromáticas foram investigadas como potentes plantas alelopáticas. A determinação dos modos da ação de aleloquímicos é um dos aspectos desafiantes em estudos alelopáticos. O objetivo deste estudo foi determinar a atividade alelopática de micropropagado Hyssopus officinalis L. infusãos aquosos. Foi avaliada a influ

  12. 不同供水水平下丁香酚和间作蚕豆对小麦光合特性的影响%Effects of eugenol and intercropped faba-bean on wheat photosynthetic characteristics under different water supplying conditions

    Institute of Scientific and Technical Information of China (English)

    赵财; 柴强

    2014-01-01

    Allelochemicals are mainly secondary substances of plant,which can influence plants growth by affecting membrane system,hormone level,minerals uptake,photosynthesis,and respiration.This exper-iment was conducted under controlled environments,and was to investigate the eugenol and intercropping effects on the photosynthetic characteristics of wheat under three water supplying conditions (75%,60%and 45% of field capacity).Results showed that eugenol at the rate of 300×10-6 mol/kg of soil negatively affected photosynthetic rate(Pn),stomata conductance(Gs)and transpiration rate(Tr)of wheat crops;the negative effect of eugenol enhanced with the decrease of irrigation rate,however,the intercropping system weakened the allelopathic effect with little negatively effect on photosynthetic characteristics of wheat un-der the same water supplying conditions.The Pn ,Gs and Tr in flag leaves of monoculture wheat decreased 13.29%,28.95% and 21.08% under eugenol treated,which decreased 7.41%,24.39% and 21.07% in the intercropping system respectively.The IWUE were significantly different between treated by eugenol and CK,and increased 17.96% in inter-cropping system.Therefore,this study demonstrated that the autotoxic-ity,often occurring with continuous cropping,could be weakened through optimizing cropping systems and improved water management.%研究以小麦根系分泌物丁香酚(2-甲氧基-3-烯丙基苯酚)为参试化感物质,研究了不同供水水平及间作蚕豆条件下丁香酚对小麦旗叶光合特性的影响.结果表明:丁香酚对单、间作小麦旗叶光合速率、气孔导度和蒸腾速率均具有抑制作用,且随供水水平的降低而增强;单作小麦旗叶光合速率、气孔导度和蒸腾速率日均值分别较对照降低13.29%、28.95%和21.08%,间作小麦降低7.41%、24.39%和21.07%,间作可弱化丁香酚的抑制作用.丁香酚处理下的单、间作小麦旗叶瞬时水分利用效率日均值分别提高10.37%

  13. 供水及丁香酚对间作小麦蚕豆生长速率及籽粒产量的影响%Effect of Eugenol and Water Application on Crop Growth Rate and Grain Yield of Wheat Fava Bean Intercropping Systems

    Institute of Scientific and Technical Information of China (English)

    朱静; 柴强; 赵财; 刘辉娟; 周海燕

    2012-01-01

    In order to provide theoretical basis for the manual control regulation of intercropping system that existed allelochemicals, pot experiment was carried out to research the effect of eugenol on crop growth rate and grain yield of wheat faba/bean intercropping system at water application of 75%, 60% and 45% field capacity. The results showed that eugenol could inhibite the crop growth rate (CGR)of fava bean in the seedling-beginning flower and pod setting-mature period of faba bean, except sole faba bean with 75% water supply level and the intercropped faba bean with 60% water supply level, increased water supply can alleviate the inhitory action of eugenol on the sole faba bean, but the inhitory action of eugenol on the intercropped fava bean exacerbate, intercropping planting pattern can alleviate the inhitory action; eugenol could inhibite the wheat CGR after seedling period, increasing water supply can not alleviate the inhitory action of eugenol, intercropping planting pattern can alleviate the inhitory action of eugenol on the wheat CGR at the stage of flowering to maturity. Compared to weighted average sole grain yield, intercropped grain yield was increased by 24.92%~52.74% under the same water supply. Other treatments showed mat allelopathy has inhibitory effect on the grain yield of two crops except 45%water supply level. Intercropping planting pattern can alleviate the allelopathy of eugeno on the wheat, fava bean grain yield.%为了寻求人工调控存在化感物质间作群体的理论依据,通过盆栽试验,探讨不同供水水平下(田问持水量的75%、60%和45%),小麦根系分泌物丁香酚对单作和间作蚕豆、小麦生长速率(Crop Growth Rate,CGR)及籽粒产量的影响.结果表明:在蚕豆苗期-始花期、结荚-成熟期2个生育阶段,丁香酚对蚕豆生长速率整体表现为抑制作用,但结荚-成熟期75%供水水平下的单作、60%供水水平下的问作除外,增加供水缓解了单作蚕豆的

  14. 巨桉凋落叶分解对假俭草生长及光合特性的影响%Effects of Eucalyptus grandis leaf litter decomposition on the growth and photosynthetic characteristics of Eremochola ophiuroides

    Institute of Scientific and Technical Information of China (English)

    李羿桥; 李西; 胡庭兴

    2013-01-01

    allelochemicals from E.grandis leaf litter decomposition can negatively affect the photosynthetic capacity and decrease the accumulation of biomass,and eventually inhibit the growth of E.ophiuroides.

  15. Hosting Capacity of Horticultural Plants for Insect Pests in Brazil Capacidad de Alojamiento de Plantas Hortícolas para Plagas de Insectos en Brasil

    Directory of Open Access Journals (Sweden)

    Germano L.D Leite

    2011-09-01

    Full Text Available Factors such as fertilization, allelochemicals, trichomes, weather, and natural enemies can influence pest populations. Thus, it is necessary to understand the factors that predispose vegetable species to pests and the role of polyculture, crop rotation, and neighboring plants. The objective of this research was to study the hosting capacity for pests of Abelmoschus esculentus (L., Brassica oleracea L. vars. acephala and capitata, Capsicum annuum L., Cucurbita moschata (Duchesne, Cucurbita maxima Duchesne and Cucumis sativus L., Lycopersicon esculentum Mill., Solanum gilo Raddi and Solanum melongena L., and Phaseolus vulgaris L. The higher density of Bemisia tabaci (Genn. adults on C. sativus can be due to the higher amount of pentacosane and octacosane in this plant. The occurrence of Brevicoryne brassicae (L. only in Brassica spp. can be accounted for by the nonacosane of these plants. The low trichome density and greater palmitic acid level can explain the greatest damage by Aphis gossypii Glover in A. esculentum. Empoasca sp. was more frequent in P. vulgaris followed by A. esculentum, which are plants with lower K content. Solanum melongena was attacked more by Hydrangea similis (Walker and Epitrix sp. perhaps because of higher palmitic acid and 11,14,17-eicosatrienoic methyl ester concentrations in their leaves. Frankliniella sp. exhibited more damage in C. sativus probably owing to higher pentacosane and octacosane in its leaves. Sistena sp. was more frequent in C. maxima and had higher octadecane levels and trichome density. The presence of ¥-humulene and hexacosane can explain the damage by Tuta absoluta (Meyrick on L. esculentum.Factores tales como la fertilización, aleloquímicos, tricomas, el clima y los enemigos naturales pueden influir en las poblaciones de plagas. Por lo tanto, es necesario comprender los factores que predisponen a las especies vegetales a las plagas y el papel de policultivos, rotación de cultivos y las plantas

  16. 不同生境中桂花叶的化感潜力研究%Compare the Allelopathic Potential of Osmanthus fragrans in Different Habitats

    Institute of Scientific and Technical Information of China (English)

    李富荣; 何桂银; 周巧劲; 阿锡英; 梁士楚

    2013-01-01

    To compare the allelopathy of Osmanthus fragrans in four different habitats,the allelopathic potential of aqueous extracts of the fresh and fallen leaves of O. fragrans to radish was studied by using indoor Petri dish bioassay method. The results showed that aqueous extracts from both the fresh and fallen leaves in the four habitats all had allelopathic effects. However,the differences of allelopathic potential existed under different situations. In the same habitat, the allelopathy inhibition of fresh leaves was usually stronger than that of fallen leaves,which may be relative to the contents and kinds of different allelochemicals. Except the fallen leaves in Qixing Park and Guilin Landscape Botanical Garden,the aqueous extracts of the other leaves significantly inhibited the seed germination of radish. In more cases, the allelopathy inhibition of the aqueous extracts of O. fragrans leaves on root growth was stronger than that on the stem length of radish seedlings. The allelopathy inhibition was beneficial to improve O. fragrans grow better in the competition with other plants. This study provided some theory basis to guide the widely cultivation and rationally arrangement of O. fragrans.%以萝卜种子为受体,采用培养皿法比较研究4种生境中桂花新鲜叶和凋落叶的化感潜力.结果表明:各生境中桂花叶片都具有一定的化感潜力,但不同情况下其化感效应有所差别.同一生境中,桂花新鲜叶比凋落叶浸提液的化感抑制作用要强,这可能与其化感物质的含量或种类有关.从植物浸提液对萝卜种子萌发率影响的结果来看,除七星公园和园林植物园桂花凋落叶对种子萌发抑制作用不明显外,其他情况下的浸提液都出现了明显的抑制效应.另外,除园林植物园桂花叶片浸提液以外,其他情况下的桂花叶片对萝卜根长的抑制效应都比对苗高的要强.桂花的化感抑制效应对其在与其他植物的竞争中获得更多资

  17. 栗与美国板栗化感作用的比较%Allelopathy comparison between Castanea mollissima and C.dentata

    Institute of Scientific and Technical Information of China (English)

    李晓娟; 王强; 倪穗; 阮晓; 王永红; 张焕; 王高峰

    2013-01-01

    intensity of water extract and 11 elution components that were separated by X-5 macropor-ous resins from water extract of C. dentata and C. mollissima. The strongest allelopathic fraction of C. dentata and C. mollissima was analyzed by liquid chromatograph-mass spectrometer technique and standard substance counterevidence experiment. Important findings Evidence of inhibition of seed germination and seedling growth of test plants indicated that water extract of C. mollissima leaf has allelopathic properties. Data on inhibition of seed germination and seedling growth in lettuce indicated that the allelopathy of C. mollissima leaves was stronger than C. dentata leaves. The allelochemicals of C. dentata and C. mollissima extracts are in 7:3, 6:4 and 5:5 elution fractions, as documented by the bioassay data. The strongest allelopathy fraction of C. dentata and C. mollissima extract (5:5 elution fraction) contained chlorogenic acid, p-hydroxybenzoic acid, protocatechuic acid, gallic acid, etc. Results suggest that the difference of chemical ecology characteristics between C. dentata and C. mollissima should not be ignored by restoration ecologists.

  18. 核桃根、茎、叶提取物对蚕豆的遗传毒性分析%Genetic toxicity of active ingredients extracted from roots,stems, and leaves of walnut on Vicia faba

    Institute of Scientific and Technical Information of China (English)

    黄元河; 潘乔丹

    2012-01-01

    increase. The experimental group's research results had significant difference compared with the controlled group's research results (P<0.05) and the concentration and time effects in the experimental concentration range (0.025-0.100 g/mL) was significant. [Conclusion]The walnut roots and leaves had allelochemicals genetic toxicity, which inhibited the division of plant cells and damaged the genetic materials of cells; this resulted in the irreversible genetic damage to the nearby plants.

  19. Phytotoxicity of the extracts of Lonchocarpus muehlbergianus Hassl. (Fabaceae leaflets and galls on seed germination and early development of lettuce Fitotoxidade diferencial dos extratos aquosos de folíolos e galhas de Lonchocarpus muelhbergianus Hassl. (Fabaceae na germinação e desenvolvimento inicial de alface

    Directory of Open Access Journals (Sweden)

    Denis Coelho de Oliveira

    2008-12-01

    Full Text Available Galls induced by Euphalerus ostreoides (Hemiptera: Psyllidae cause structural and chemical alterations on Lonchocarpus muehlbergianus leaflets. Healthy and galled leaflet tissues of this plant species are rich in secondary metabolites with potential allelopathic effects. This research compares the allelopathic effects of the aqueous extracts of L. muehlbergianus leaflets and galls on seeds and seedlings of Lactuta sativa, and evaluates the chemical impact produced by a gall-inducing insect on the other trophic levels associated with it. The extracts were obtained through static maceration in distilled water (5% p/v. The treatments consisted of aqueous crude extracts and those previously filtered in polyvinylpirrolidone (PVP. After seven days, seedling height was measured, and the radicles were fixed in FAA50 for anatomical analyses. Healthy leaflet and gall aqueous extracts, and those filtered in PVP, significantly inhibited seed germination, with no significant differences between the two groups. Treatments with aqueous extracts reduced seed germination speed and vegetative axis length. Plant tissue alterations confirm the phytotoxicity of allelochemical substances present in the extracts. The differences among the treatments indicated that gall formation altered L. muehlbergianus leaflet metabolism, and this could influence the other trophic levels associated with this gall inducing-host plant system.Galhas induzidas por Euphalerus ostreoides (Hemiptera: Psyllidae produzem alterações estruturais e químicas nos folíolos de Lonchocarpus muehlbergianus. As galhas, em geral, atuam como drenos de fotoassimilados podendo acumular tanto compostos do metabolismo primário, associados à alimentação do inseto quanto do metabolismo secundário, relacionados às inter-relações da planta-hospedeira com o galhador e demais níveis tróficos associados. Tecidos sadios e galhados de L. muehlbergianus são ricos em metabólitos com efeito alelop

  20. Allelopathic Effects of Cyanobacterial Filtrates on Baltic Diatom

    Science.gov (United States)

    Śliwińska, Sylwia; Latała, Adam

    2012-01-01

    Allelopathy may be one of the factors affecting the formation of massive and harmful algal blooms in aquatic environments. Recent studies indicate that blooms of cyanobacteria in the Baltic Sea has grown significantly in last decades, so it is important to determine the allelopathic interactions between the dominant species of cyanobacteria and microalgae. In this work we investigated the influence of allelopathic compounds on the growth of Skeletonema marinoi by addition of cell-free filtrate of the Baltic cyanobacterium Nodularia spumigena cultures grown under different temperature (15-25°C). Additionally the effects of filtrates of both an exponential and a stationary growing culture of N. spumigena were tested on diatom. These studies indicate that high temperature affected the donor species by increasing its production of allelochemicals. The highest drop of growth of analyzed diatom were observed after the addition of cell-free filtrate obtained from N. spumigena grown at 25°C and constituted 70% of their control. N. spumigena was only allelopathic in exponential growth phase, whereas the cyanobacteria filtrate from stationary phase have any effect on S. marinoi. These findings suggest that N. spumigena may reveal allelopathic activity and that the production of allelopathic substances is influenced by the temperature and growth phase of cyanobacteria. Allelopatia może być kluczowym czynnikiem wpływającym na tworzenie się masowych zakwitów sinic w wielu wodnych ekosystemach. Badania pokazują, że zakwity sinic w Morzu Bałtyckim w ostatnich dekadach znacznie się nasiliły, dlatego tak ważne jest określenie stopnia oddziaływania allelopatycznego dominujących w tym akwenie gatunków fitoplanktonu. W przeprowadzonych badaniach określono wpływ związków allelopatycznych produkowanych przez bałtycką sinicę Nodularia spumigena hodowaną w różnych temperaturach (15-25°C) na wzrost okrzemki Skeletonema marinoi. Dodatkowo w niniejszej pracy por

  1. Effects of water extracts from Solidago canadensis on the growth of maize seedlings and the underlying photosynthetic mechanisms%加拿大一枝黄花水提液对玉米幼苗生长的化感作用及其机理

    Institute of Scientific and Technical Information of China (English)

    叶小齐; 吴明; 邵学新; 梁雷

    2014-01-01

    植物化感物质普遍存在对其他植物生长的“低促高抑”现象,可能和植物对叶片资源投入或者单位叶面积光合能力有关。实验以具有较强化感作用的加拿大一枝黄花为材料,研究其提取物对玉米幼苗生长、光合能力和叶片资源分配的影响。结果表明,不同水提液浓度(0.00~0.25 g/mL)对玉米幼苗生长(总根长、株高、总叶面积和总叶长)存在着显著的影响(P <0.05),与对照处理(0.00 g/mL)相比,0.02~0.11 g/mL 内各浓度处理对玉米幼苗的茎、叶和根的生长和总生物量的积累都有促进效应,而在0.13~0.25 g/mL 内各浓度处理有抑制效应。不同浓度水提液处理对比叶面积和叶面积率有着相似的“低促高抑”效应(P <0.05),低浓度处理玉米幼苗对光合同化组织的资源投入增加,比叶面积和叶面积率提高,而叶生物量分配则无显著变化(P >0.05)。处理1~3 d 内,具有最大生长促进效应的0.02 g/mL 处理和最大生长抑制效应的0.20 g/mL 处理与对照处理的玉米幼苗最大净光合速率和表观量子效率没有显著差异(P >0.05)。不同浓度处理条件下,玉米幼苗生物量与比叶面积和叶面积率呈极显著正相关(P <0.001),这说明加拿大一枝黄花水提液对玉米幼苗生长的影响是通过改变对叶片资源投入,特别是叶面积生长的投入,而不是通过单位叶面积光合能力变化所导致的。低浓度化感物质对玉米幼苗生长的促进可能是细胞伸展性增强的结果。不同浓度化感物质可能是化感作用感知受体植物胁迫能力的一种信号,因此具有一定的生态适应意义。%Although hormesis is commonly observed with the effects of plant allelochemicals on plant growth, the mechanisms underlying this phenomenon are not clearly understood.Allelochemicals may affect

  2. Effects of Litter on the Seedling Regeneration and Seed Germination of Rhododendron agastum%凋落物对迷人杜鹃幼苗更新和种子萌发的影响

    Institute of Scientific and Technical Information of China (English)

    周艳; 陈训; 韦小丽; 伍庆; 李朝婵

    2015-01-01

    decreased by 83. 0% and 68. 8%,respectively,with the embryo root growth completely stopped. These present results suggested that litter would have a physical and allelopathy effect. The litter appeared to act as a physical obstacle that prevented seedlings from rooting, and also impeded their growth. Furthermore,the litter led to low-light conditions that suppressed seed germination. Allelochemicals present in the litter also inhibited seed germination and seedling formation,which was evidenced by the fact that the litter extractions by using diethyl ether,ethyl acetate,and n-butanol contained 29,16,and 4 allelochemicals,respectively by gas chromatography-mass spectrometry. [Conclusion]Thus, in Rhododendron forest tending management, reasonably cleaning up litters could promote the natural regeneration of Rh. agastum seedlings.

  3. 近十年中国生物入侵研究进展%Progress of biological invasions research in China over the last decade

    Institute of Scientific and Technical Information of China (English)

    鞠瑞亭; 李慧; 石正人; 李博

    2012-01-01

    the field of biological invasions research in China over the last decade, there are still large knowledge gaps. This paper reviews progress in the field of biological invasions research since 2000 as it relates to China, covering the diversity, colonization and immigration patterns of invasive species, mechanisms and ecological effects of biological invasions, and management and control of invasive species. In China, 529 invasive alien species have been identified, which originated primarily from South and North America, and the major taxa included terrestrial plants, terrestrial invertebrates, and microorganisms. We found a higher prevalence of invasive species in the eastern and southern provinces, compared to the western and northern provinces in China. This pattern is likely due to the differences in the level of economic development and environmental suitability between the two regions. Moreover, with further economic development, China may face more serious biological invasions in the future. These invasions of alien species are largely the combined results of the interactions between the intrinsic traits of these species along with resource opportunities and disturbances by human beings. Many mechanisms are responsible for successful invasions of alien species, but phenotypic plasticity, adaptive evolution, enemy release, interspecific mutualism or commensalism, and new allelochemicals may be primary causative factors. Biological invasions in China have caused serious impacts on native ecosystems, including biodiversity and ecosystem services, alteration of biogeochemical cycles, threats to agricultural and forestry production, traffic and shipping, environmental safety, and public facilities. China has also made progress in the detection and monitoring of invasive species, risk analysis, biological control, radical elimination, and ecological restoration of degraded ecosystems. We suggest several issues that need to be addressed in invasive species research in

  4. Research progress on Merremia boisiana%金钟藤研究述评

    Institute of Scientific and Technical Information of China (English)

    王伯荪; 彭少麟; 李代江; 周婷

    2009-01-01

    Recent researches demonstrated that Merremia boisiana is a photophilous heliophyte liana rather than a sciophyte, which has a wide ecological adaptability and contains the allelo-chemicals, one of invasion mechanisms of invasive species. In China, M. boisiana had a distri-bution in Yunnan, Guangxi, and Guangdong Provinces, but its distribution in Fujian Province has not been confirmed. Guangzhou City and its vicinity are becoming a new distribution area of M. boisiana due to its northward invasion from Hainan under global warming. However, M. boi-siana is not really a kind of tropical plants, but one of the tropical and subtropical elements. The tropic of cancer is the north boundary of M. boisiana distribution, and thereby, there is a high possibility that M. boisiana is a latent local species activated by global warming. M. boisiana causes widespread disaster in its holotype locality (Vietnam) and its original distribution center (Hainan Province), which is not consistent with the existing viewpoint that the invasive species cannot spread to be a disaster owing to the natural enemies in origin, while suggests that there are no fatal natural enemies in the origin. The widely spreading to be a disaster is originated from the intrinsic ecosystem being destroyed by disturbances, which causes the worsened, broken, and heterogeneous habitat. The reduced community biodiversity and functional group diversity intensi-fy the invasive possibility of exotic communities and provide chance for invasive species. There-fore, the viewpoint that the invasion of M. boisiana is non-selective should be modified, and the prevention measures of M. boisiana remain to be break through. Integrative control should be the first choice. Additionally, protecting the natural ecosystem from disturbance, and reconstructing and optimizing the destroyed ecosystem would be the necessary strategies and measures.%述评了近年来有关金钟藤的报道和研究成果,论证确认金钟藤是喜

  5. 紫茎泽兰叶片凋落物对入侵地4种草本植物的化感作用%Allelopathic effect of Ageratina adenophora(Spreng.)leaf litter on four herbaceous plants in invaded regions

    Institute of Scientific and Technical Information of China (English)

    万欢欢; 刘万学; 万方浩

    2011-01-01

    extract. For the growth of G parvifiora and M. sativa seedling, a significant promotion effect was noted at low water extract concentration. However, herbaceous plant seedling growth (except for L. perenne) was significantly inhibited at high water extract concentration. The effect of water extracts on L. perenne seedling growth was insignificant. Furthermore, pot experiments showed that T. repens seedling growth was significantly inhibited by 50 g · kg-1 leaf litter. T. repens biomass, however, increased by 71.25% with the addition of active carbon (AC). This further testified an obvious alteiopathic inhibition effect of leaf litter on herbaceous plant in invaded soils. By leaf litter decomposition and releasing allelochemicals into soils, A. adenophora inhibited seed germination and seedling growth of accompanying plants, created a favorable environment for invasion and expansion.

  6. Determination of Allelopathic Effect of Thalia dealbata—An Exotic Aquatic Plant%外来水生植物再力花的化感作用探析

    Institute of Scientific and Technical Information of China (English)

    缪丽华; 王媛

    2012-01-01

    Allelopathy is an important mechanism for exotic plants influencing on the growth of native plants. As an exotic aquatic plant, Thalia dealbata is widely used in landscape design during recent years. In order to testify whether Thalia dealbata would have negative effect on the growth of its surrounding plant species, extracts from different tissues of Thalia dealbata were isolated and, with the help of seed germination test, to determine their effects on seed germination and seedling growth among three sensitive species including turnip (Raphanus sati-vus), Chinese cabbage (Brassica chinensis) and cucumber (Brassica chinensis). The results indicated that the extracts from different parts of Thalia dealbata all had inhibition effect on the three test species, among which extract from leaf and rhizome tissue showed the most significant effect on seed germination and seedling growth, respectively. Leaf extract (50 mg/mL) significantly (p<0.05) affected seed germination of test plants, but the extract of other plant parts with an inhibition rate of 30.49% to 40.26% for turnip, 2.33% to 85.19% for Chinese cabbage and 0% to 10.53% for cucumber, respectively. Results also indicated that extracts from all parts of Thalia dealbata could inhibit seedling growth. Negative effects were detected in root length, shoot length, fresh mass and dry mass in the experiment on the three plants. And this effect of inhibition showed a positive correlation with the concentration of tissue extracts. High density extracts showed significantly (p<0.01) inhibition on seedling growth. Inhibition rate of 50 mg/mL extract solution on root length was 51.21% for turnip, 91.7% for Chinese cabbage and 45.71% for cucumber, and inhibition rate on shoot length was 51.21%, 69.66% and 45.71%, respectively. Also it could be concluded that allelochemicals existed in all part of Thalia dealbata and the strongest allelopathic effect came from rhizome, followed by root, leafstalk and leaf tissue

  7. Research advances in the relation between plant root exudates and rhizosphere micro-environment in the made-made wetlands%人工湿地植物根系分泌物与根际微环境相关性的研究进展

    Institute of Scientific and Technical Information of China (English)

    李稹; 黄娟; 姜磊; 徐文杰; 王其东; 陈曦

    2012-01-01

    physiological characteristics around the root. In addition, since many plants can release allelo-chemicals by different methods, bringing about some effects on the growth of surrounding plants, a lot of research articles have been dedicated to the analysis of the effects of plant root exudates on the rhizosphere micro-environment in the aspects of improving nutrients threatening, metal toxicity and the growth of rhizosphere microbes and allelopathy. And, finally, some comments are given intended to point out the research achievements on the plant rhizosphere in constructed wetlands. Hence, we would like to suggest that further research is needed on the inherent mechanism of plant-releasing exudates and its relation with the plant stress resistance.%人工湿地中植物发挥着至关重要的作用.植物根系能向基质中释放糖类、酸类等分泌物,从而影响根际微生物种类及分布等微环境特征,因此植物根系分泌物与根际微环境的关系逐渐受到关注.综述了近10年来植物根系分泌物组成与分泌机理等方面的研究进展,分析了温度、pH值、光照等环境因子及养分含量、微生物等对根系分泌物的影响,探讨了根系分泌物在养分胁迫的改善、金属毒性的改善、对根际微生物的影响及化感作用等方面对微环境的影响.在此基础上提出明确植物根系分泌内在机制及其与植物抗逆性的关系等研究方向.

  8. 影响植物竞争的因子%A review on factors affecting plant competition

    Institute of Scientific and Technical Information of China (English)

    薛立; 傅静丹

    2012-01-01

    The competition refers to the interactions of two or more individuals which compete for resources, and is a key process of plant populations and communities. A comprehensive and mechanistic understanding of plant competition is necessary to predict the responses of ecological systems to environmental changes. The inside factors affecting competition include plant density, biological factors and the biomass. The environmental factors related to competition include light, soil moisture, soil nutrient and altitude. High-density affects plant competition by controlling plant growth. Allelochemicals produced by plants directly affect their neighbors. Trees and grasses may compete for resources where their root systems overlap. Herbivorous animals chose to eat some plants, resulting in reduction of competition ability of the plants. Plants make morphological shifts and alter the competitive ability between above-ground and below-ground parts in response to the environmental changes. When shade-tolerant species are absent in mixed forest, less shade-tolerant species could maintain their dominance for a long period. In contrast, mixed forest with tolerant species would reduce the dominance of less-tolerant species, maintain and probably increase the dominance through the decline of less-tolerant species. Smaller plants should have longer survival time due to their smaller total water requirements when water is scarce, and the longer survival of plants with higher root allocation could be due to a relative reduction in transpiring surface per unit root length. In nutrient-deficient soils, plants are stressed directly by the lack of adequate nutrients and competitive interactions may be controlled by a plant's ability to efficiently take up available nutrients. In nutrient-sufficient soils, plants with the highest maximum growth rates may well be the superior competitors. Intensity of light competition declines with altitude. The future research about competition will focus