WorldWideScience

Sample records for allelochemicals

  1. Probing Allelochemical Biosynthesis in Sorghum Root Hairs

    Science.gov (United States)

    Allelopathic interaction between plants is thought to involve the release of phytotoxic allelochemicals by one species, thus inhibiting the growth of neighboring species in competition for limited resources. Sorgoleone represents one of the more potent allelochemicals characterized to date, and its...

  2. 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.

  3. 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.

  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. PMID:27147531

  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. EVALUATION OF ALLELOPATHIC POTENTIAL OF RUMEX DENTATUS ROOT EXTRACT AND ALLELOCHEMICALS ON CICER ARIETINUM

    OpenAIRE

    Hamed M. El-Shora; Ahmed M. Abd El-Gawad

    2014-01-01

    The present study aimed to evaluate the allelopathic potential of root extract of Rumex dentatus L. and various allelochemicals on some physiological parameters in roots of Cicer arietinum L. The tested allelochemicals were benzoic, caffeic, cinnamic, ferulic, gallic, sinapic and vanillic acids. Seed germination of Cicer was inhibited by Rumex extract. Lipid peroxidation and hydrogen peroxide production increased gradually in response to extract concentration as well as allelochemicals treatm...

  7. Allelochemical Stress Can Trigger Oxidative Damage in Receptor Plants: Mode of Action of Phytotoxicity

    OpenAIRE

    Cruz-Ortega, Rocio; Lara-Núñez, Aurora; Anaya, Ana Luisa

    2007-01-01

    Plants can interact with other plants through the release of chemical compounds or allelochemicals. These compounds released by donor plants influence germination, growth, development, and establishment of receptor plants; having an important role on the pattern of vegetation, i.e as invasive strategy, and on crop productivity. This phytotoxic or negative effect of the released allelochemicals (allelochemical stress) is caused by modifying or altering diverse metabolic processes, having many ...

  8. 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...

  9. 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. PMID:27137194

  10. Allelochemicals from the Rhizosphere Soil of Cultivated Astragalus hoantchy.

    Science.gov (United States)

    Guo, Kai; He, Xiaofeng; Yan, Zhiqiang; Li, Xiuzhuang; Ren, Xia; Pan, Le; Qin, Bo

    2016-05-01

    Astragalus hoantchy, a widely cultivated medicinal plant species in traditional Chinese and Mongolian medicine, has been often hampered by replant failure during cultivation, like many other herbs of the genus Astragalus. Root aqueous extracts of Astragalus herbs were reported to exhibit allelopathic activity against other plants and autotoxic activity on their own seedlings, but the allelochemicals released by Astragalus plants have not been specified so far. Ten compounds were isolated from the rhizosphere soil extract of cultivated A. hoantchy and elucidated by spectroscopic analysis. Compounds 1-6 observably showed allelopathic activity against Lactuca sativa seedlings and autotoxic activity against A. hoantchy seedlings. The isolated compounds were further confirmed and quantified by high-performance liquid chromatography (HPLC) in the rhizosphere soil, with a total concentration of 9.78 μg/g (dry weight). These results specify and verify the allelochemicals released by cultivated A. hoantchy into the soil environment, which may provide new insights into the allelopathic mechanisms of this medicinal plant and probably assist in clarifying the replant problems of Astragalus plants. PMID:27074954

  11. Allelochemical, Eudesmane-Type Sesquiterpenoids from Inula falconeri

    Directory of Open Access Journals (Sweden)

    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. 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....... The most dominant dietary benzoxazinoid, 2-β-D-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one (DIBOA-Glc), was apparently reduced to 2-β-Dglucopyranosyloxy-1,4-benzoxazin-3-one (HBOA-Glc), the most dominant circulating benzoxazinoid in the plasma in all three experiments. Eight different...... benzoxazinoids and their derivatives including some glucuronide and sulfate conjugates were excreted through the urine, HBOA-Glc being the most dominant urinary benzoxazinoid. Interestingly, 2-amino-3H-phenoxazin-3-one, a potent antibiotic, was also detected in the bile and urine. These results indicate that...

  13. LC-MS based Metabolomics Analysis to Identify Potential Allelochemicals in Wedelia trilobata

    OpenAIRE

    Kamalrul Azlan Azizan; Sarah Ibrahim; Nurul Haizun Abdul Ghani; Mohammad Firdaus Nawawi

    2016-01-01

    Wedelia trilobata is a noxious invasive weed that has been widely cultivated as a decorative and groundcover plant. The plant has been reported to contain diverse bioactive compounds with a broad spectrum of biological activities including allelochemicals. Allelochemicals contribute to allelopathy interactions that suppress the growth and development of nearby plants. Several studies have reported the allelopathic potential of W. trilobata and its negative effects to crop plants. However, rel...

  14. 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.

  15. LC-MS based Metabolomics Analysis to Identify Potential Allelochemicals in Wedelia trilobata

    Directory of Open Access Journals (Sweden)

    Kamalrul Azlan Azizan

    2016-05-01

    Full Text Available Wedelia trilobata is a noxious invasive weed that has been widely cultivated as a decorative and groundcover plant. The plant has been reported to contain diverse bioactive compounds with a broad spectrum of biological activities including allelochemicals. Allelochemicals contribute to allelopathy interactions that suppress the growth and development of nearby plants. Several studies have reported the allelopathic potential of W. trilobata and its negative effects to crop plants. However, relatively little is known about the allelochemicals’ composition and how allelochemicals contribute to the allelopathic behavior of this plant. In order to prove allelopathy, the identification of the causative allelochemicals is required. The identification of potential allelochemicals that serve as biomarkers could be useful for assessing allelopathy interactions. In this study, a liquid chromatography (LC based metabolomics approach was applied to find biomarkers with allelopathic effects from W. trilobata. Ethanol and water were used to extract metabolites from the leaves of W. trilobata and analyzed using liquid chromatography coupled with quadrupole high-resolution time of flight mass spectrometry (LC-QTOF-MS. Using multivariate statistical analysis (MVA, we identified eight Rt-m/z pairs as candidate marker compounds for assessing allelopathy interactions of W. trilobata. The results highlight the application of metabolomics for understanding of the role of allelochemicals in allelopathy interactions of W. trilobata .

  16. 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.

  17. Variation of hairy vetch seed weight alters germination and seedling growth response to an allelochemical

    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 controlled more effectively than large-seeded species. In our...

  18. The fungal fast lane: common mycorrhizal networks extend bioactive zones of allelochemicals in soils.

    Directory of Open Access Journals (Sweden)

    E Kathryn Barto

    Full Text Available Allelopathy, a phenomenon where compounds produced by one plant limit the growth of surrounding plants, is a controversially discussed factor in plant-plant interactions with great significance for plant community structure. Common mycorrhizal networks (CMNs form belowground networks that interconnect multiple plant species; yet these networks are typically ignored in studies of allelopathy. We tested the hypothesis that CMNs facilitate transport of allelochemicals from supplier to target plants, thereby affecting allelopathic interactions. We analyzed accumulation of a model allelopathic substance, the herbicide imazamox, and two allelopathic thiophenes released from Tagetes tenuifolia roots, by diffusion through soil and CMNs. We also conducted bioassays to determine how the accumulated substances affected plant growth. All compounds accumulated to greater levels in target soils with CMNs as opposed to soils without CMNs. This increased accumulation was associated with reduced growth of target plants in soils with CMNs. Our results show that CMNs support transfer of allelochemicals from supplier to target plants and thus lead to allelochemical accumulation at levels that could not be reached by diffusion through soil alone. We conclude that CMNs expand the bioactive zones of allelochemicals in natural environments, with significant implications for interspecies chemical interactions in plant communities.

  19. Study on the release routes of allelochemicals from Pistia stratiotes Linn., and its anti-cyanobacteria mechanisms on Microcystis aeruginosa.

    Science.gov (United States)

    Wu, Xiang; Wu, Hao; Ye, Jinyun; Zhong, Bin

    2015-12-01

    Allelochemicals in Pistia stratiotes Linn. have a strong anti-cyanobacteria effect on Microcystis aeruginosa. To further determine the release routes of allelochemicals in P. stratiotes and understand their anti-cyanobacteria mechanisms, we aimed to systematically investigate the allelopathic effects of leaf leachates, leaf volatilization, root exudates, and residue decomposition of P. stratiotes on M. aeruginosa. The influences of P. stratiotes allelochemicals on the physiological properties of M. aeruginosa were also studied. Root exudates of P. stratiotes exhibited the strongest inhibitory effect on M. aeruginosa growth. The residue decomposition and leaf leachates exhibited a relatively strong inhibitory effect on M. aeruginosa growth. By contrast, the leaf volatilization stimulated M. aeruginosa growth. Therefore, root exudation was determined to be the main release route of allelochemicals from P. stratiotes. The mixed culture experiment of P. stratiotes root exudates and M. aeruginosa showed that the allelochemicals released from root exudation had no effect on the electron transfer of M. aeruginosa photosynthetic system II. However, it reduced the phycocyanin (PC) content and phycocyanin to allophycocyanin (PC/APC) ratio in the photosynthetic system. As the root exudates concentration increased, the electrical conductivity (EC) and superoxide anion radical (O2(*-)) values in the M. aeruginosa culture fluid increased significantly, indicating that the allelochemicals released from the root of P. stratiotes inhibited algae growth by affecting the PC and PC/APC levels in photosynthesis, destroying the cell membrane, and increasing O2(*-) content to result in oxidative damage of M. aeruginosa. PMID:26233747

  20. An Allelochemical from Myrica gale with Strong Phytotoxic Activity against Highly Invasive Fallopia x bohemica Taxa

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    Florence Piola

    2011-03-01

    Full Text Available We report the identification of the allelochemical 3-(1-oxo-3-phenylpropyl-1,1,5-trimethylcyclo-hexane-2,4,6-trione, known as myrigalone A, from the fruits and leaves of Myrica gale. The structure of the compound was confirmed by high-resolution techniques (UV, MS and NMR analysis. The compound is phytotoxic towards classical plant species used for allelochemical assays and also against Fallopia x bohemica, a highly invasive plant. Application of either powdered dry leaves or dry fruits of M. gale also showed in vitro phytotoxic activity. We hypothesize that M. gale could be used as a green allelopathic shield to control Fallopia x bohemica invasion, in addition to its potential use as an environmentally friendly herbicide.

  1. The Fungal Fast Lane: Common Mycorrhizal Networks Extend Bioactive Zones of Allelochemicals in Soils

    OpenAIRE

    Barto, E. Kathryn; Hilker, Monika; Müller, Frank; Mohney, Brian K.; Weidenhamer, Jeffrey D.; Rillig, Matthias C

    2011-01-01

    Allelopathy, a phenomenon where compounds produced by one plant limit the growth of surrounding plants, is a controversially discussed factor in plant-plant interactions with great significance for plant community structure. Common mycorrhizal networks (CMNs) form belowground networks that interconnect multiple plant species; yet these networks are typically ignored in studies of allelopathy. We tested the hypothesis that CMNs facilitate transport of allelochemicals from supplier to target pl...

  2. Evaluation of Allelopathic Potential of Rumex dentatus Root Extract and Allelochemicals on Cicer arietinum

    Directory of Open Access Journals (Sweden)

    Hamed M. El-Shora

    2014-03-01

    Full Text Available The present study aimed to evaluate the allelopathic potential of root extract of Rumex dentatus L. and various allelochemicals on some physiological parameters in roots of Cicer arietinum L. The tested allelochemicals were benzoic, caffeic, cinnamic, ferulic, gallic, sinapic and vanillic acids. Seed germination of Cicer was inhibited by Rumex extract. Lipid peroxidation and hydrogen peroxide production increased gradually in response to extract concentration as well as allelochemicals treatment. The total soluble protein decreased whereas the total phenol increased under the various treatments. The activities of superoxide dismutase (SOD: 1.15.1.1 and catalase (CAT: 1.11.1.6 increased continuously with increasing extract concentration. However, peroxidase (POD: 1.11.1.7 increased sharply at 2% (w/v followed by reduction at the higher concentrations and reached 1.1 U g-1 fresh weight at 10% (w/v which was still higher than that of the control value. Ferulic acid was the most effective inducer for SOD activity followed by cinnamic acid. The POD activity increased remarkably particularly with cinnamic, benzoic and gallic acids. Sinapic, ferulic and coumaric acids enhanced CAT activity by 150.4%, 139.5% and 124.4%, respectively. The results reveal the possible use of R. dentatus as bioherbicide.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Effects of allelochemical extracted from water lettuce (Pistia stratiotes Linn.) on the growth, microcystin production and release of Microcystis aeruginosa.

    Science.gov (United States)

    Wu, Xiang; Wu, Hao; Chen, Junren; Ye, Jinyun

    2013-11-01

    This study explored the optimisation of a method of extracting allelochemicals from Pistia stratiotes Linn., identified the optimal dose range for the allelochemicals' anti-algal effect and investigated their impact on the growth of Microcystis aeruginosa, as well as the production and release of microcystin-LR (MC-LR). Based on measured changes in algal cell density and chlorophyll a (Chl-a) content, the allelochemicals were confirmed to have the strongest anti-algal effect with the lowest half-effect concentration of 65 mg L(-1) when they were extracted using ethyl acetate as the extraction solvent, 1:20 g mL(-1) as the extraction ratio and 1 h as the extraction time. The allelochemicals extracted from P. stratiotes using this optimal method exhibited the strongest inhibitory effect on the growth of algae when used within a dose range of 60-100 mg L(-1); the relative inhibitory ratio reached 50-90%, and Chl-a content reduced 50-75% in algae cell cultures within 3-7 days. In addition, the extracted allelochemical compounds demonstrated no significant impact on the extracellular release of MC-LR during the culturing period. The amount of intracellular MC-LR per 10(6) algal cells increased depending on the increasing dose of allelochemicals from P. stratiotes after 7 days of culturing and maintained stability after 16 days. There was no increase in the total amount of MC-LR in the algal cell culture medium. Therefore, the application of allelochemicals from P. stratiotes to inhibit M. aeruginosa has a high degree of ecological safety and can be adopted in practical applications for treating water subjected to algae blooms because the treatment can effectively inhibit the proliferation of algal cells without increasing the release of cyanotoxin. PMID:23653319

  5. Antioxidant enzyme level response to prooxidant allelochemicals in larvae of the southern armyworm moth, Spodoptera eridania.

    Science.gov (United States)

    Pritsos, C A; Ahmad, S; Elliott, A J; Pardini, R S

    1990-01-01

    Larvae of the southern armyworm, Spodoptera eridania, are highly polyphagous feeders which frequently encounter and feed upon plants containing high levels of prooxidant allelochemicals. While ingestion of moderate quantities of prooxidants can be tolerated by these larvae, ingestion of larger quantities can result in toxicity. Studies were conducted to assess the role of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) in the protection of S. eridania against redox active prooxidant plant allelochemicals. Dietary exposure of mid-fifth-instar larvae to either quercetin (a flavonoid) or xanthotoxin (a photoactive furanocoumarin), which generate superoxide radical, and singlet oxygen, respectively, resulted in an increase in SOD levels. CAT levels increased in all groups of S. eridania including control insects. This may have been due to the sudden exposure to food following an extended fast of 18 h (to insure that larvae would not reject the diet because of the prooxidants' bitter taste) with an eventual lowering of CAT values with time. GR activities did not significantly change except for a slight inhibition at the highest prooxidant concentrations used at 12-h post-ingestion. The data from these studies suggest that SOD responds to prooxidant challenges in these insects and together with CAT and GR contributes to the insect's defense against potentially toxic prooxidant compounds. PMID:2161387

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

    Directory of Open Access Journals (Sweden)

    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.

  7. 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. PMID:25736610

  8. 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.

  9. Isolation of bioactive allelochemicals from sunflower (variety Suncross-42) through fractionation-guided bioassays.

    Science.gov (United States)

    Anjum, Tehmina; Bajwa, Rukhsana

    2010-11-01

    Plants are rich source of biologically active allelochemicals. However, natural product discovery is not an easy task. Many problems encountered during this laborious practice can be overcome through the modification of preliminary trials. Bioassay-directed isolation of active plant compounds can increase efficiency by eliminating many of the problems encountered. This strategy avoids unnecessary compounds, concentrating on potential components and thus reducing the cost and time required. In this study, a crude aqueous extract of sunflower leaves was fractionated through high performance liquid chromatography. The isolated fractions were checked against Chenopodium album and Rumex dentatus. The fraction found active against two selected weeds was re-fractionated, and the active components were checked for their composition. Thin layer chromatography isolated a range of phenolics, whereas the presence of bioactive terpenoids was confirmed through mass spectroscopy and nuclear magnetic resonance spectroscopy. PMID:20981619

  10. Effect of qualitative and quantitative variation in allelochemicals on a generalist insect: Iridoid glycosides and the southern armyworm.

    Science.gov (United States)

    Puttick, G M; Bowers, M D

    1988-01-01

    The behavioral and physiological effects of plant allelochemicals have been difficult to demonstrate; it is not often clear whether the compounds are deterrent, toxic, or both. In this study, we compared the qualitative and quantitative effects of several iridoid glycosides on a generalist lepidopteran herbivore,Spodoptera eridania (Noctuidae). Larval growth and survivorship and larval preference or avoidance were measured on artificial diets containing different iridoid glycosides at different concentrations. We also tested the toxicity/deterrence of these compounds. We found that iridoid glycosides retarded larval growth significantly at relatively low concentrations and that they were usually avoided in preference tests. The toxicity/ deterrence test did not always reflect the results of these other tests. The merits of using a variety of methods for determining deterrence and/or toxicity of plant allelochemicals are discussed. PMID:24277013

  11. Preliminary Characterization of Extracellular Allelochemicals of the Toxic Marine Dinoflagellate Alexandrium tamarense Using a Rhodomonas salina Bioassay

    OpenAIRE

    Allan Cembella; Bernd Krock; Haiyan Ma; Urban Tillmann

    2009-01-01

    Members of the marine dinoflagellate genus Alexandrium are known to exude allelochemicals, unrelated to well-known neurotoxins (PSP-toxins, spirolides), with negative effects on other phytoplankton and marine grazers. Physico/chemical characterization of extracellular lytic compounds of A. tamarense, quantified by Rhodomonas salina bioassay, showed that the lytic activity, and hence presumably the compounds were stable over wide ranges of temperatures and pH and were refractory to bacterial d...

  12. Volatile allelochemicals in the Ageratum conyzoides intercropped citrus orchard and their effects on mites Amblyseius newsami and Panonychus citri.

    Science.gov (United States)

    Kong, Chuihua; Hu, Fei; Xu, Xiaohua; Zhang, Maoxin; Liang, Wenju

    2005-09-01

    Ageratum conyzoides L. weed often invades cultivated fields and reduces crop productivity in Southeast Asia and South China. However, intercropping this weed in citrus orchards may increase the population of predatory mite Amblyseius newsami, an effective natural enemy of citrus red mite Panonychus citri, and keep the population of P. citri at low and noninjurious levels. This study showed that A. conyzoides produced and released volatile allelochemicals into the air in the intercropped citrus orchard, and these volatiles influenced the olfactory responses of A. newsami and P. citri. At test temperature (25 degrees C), A. conyzoides fresh leaves, its essential oil, and major constituents, demethoxy-ageratochromene, beta-caryophyllene, alpha-bisabolene, and E-beta-farnesene, attracted A. newsami and slightly repelled P. citri. Field experiments demonstrated that spraying A. conyzoides essential oil emulsion in an A. conyzoides nonintercropped citrus orchard increased the population density of A. newsami from below 0.1 to over 0.3 individuals per leaf, reaching the same level as in an A. conyzoides intercropped citrus orchard. However, this effect could not be maintained beyond 48 hr because of the volatility of the essential oil. In contrast, in the A. conyzoides intercropped citrus orchard, A. conyzoides plants continuously produced and released volatile allelochemicals and maintained the A. newsami population for a long time. The results suggest that intercropping of A. conyzoides not only made the citrus orchard ecosystem more favorable for the predatory mite A. newsami, but also that the volatile allelochemicals released from A. conyzoides regulated the population of A. newsami and P. citri. PMID:16132220

  13. Isolation and identification of allelochemicals produced by B. sonorensis for suppression of charcoal rot of Arachis hypogaea L.

    Science.gov (United States)

    Pandya, Urja; Saraf, Meenu

    2015-05-01

    Bacillus sonorensis MBCU2 isolated from vermicompost-amended soil from Gujarat, India showed most antagonistic activity against Macrophomina phaseolina by dual culture screening. The culture supernatant of MBCU2 completely suppressed the mycelia growth of pathogen, indicating that suppression was due to the presence of allelochemicals in the culture filtrate. Results of scanning electron microscopy revealed that MBCU2 caused morphological alteration in mycelia of M. phaseolina as evident by hyphal lysis and perforation. Lipopeptides (iturin A and surfactin) produced by MBCU2 were detected and identified by MALDI-TOF-MS as well as liquid chromatography coupled with ESI-MS/MS. Pot trial studies conducted by seed bacterization with MBCU2 resulted in statistically significant increase in Arachis hypogaea L. vegetative growth parameters such as root length (91%), shoot length (252%), fresh weight (71%), dry weight (57%), number of pod (128%), and number of seed (290%) in M. phaseolina infested soil over control as well as decreased M. phaseolina disease severity. We suggest that allelochemicals production can be linked to the mechanism of protection of A. hypogaea L. from M. phaseolina by B. sonorensis MBCU2. PMID:25346523

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

    Directory of Open Access Journals (Sweden)

    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

  15. Continuous-release beads of natural allelochemicals for the long-term control of cyanobacterial growth: Preparation, release dynamics and inhibitory effects.

    Science.gov (United States)

    Huang, Haomin; Xiao, Xi; Lin, Fang; Grossart, Hans-Peter; Nie, Zeyu; Sun, Lijuan; Xu, Chen; Shi, Jiyan

    2016-05-15

    The effects of allelochemicals on cyanobacterial blooms have been observed for more than 20 years; however, the use of these compounds, usually involving a "direct-added" mode, has clear disadvantages, such as a short activity period or temporarily excessive localized concentration. Here, a simulated-allelopathy mode to facilitate the application of allelochemicals was proposed and tested on Microcystis aeruginosa. The continuous-release beads of 5,4'-dihydroxyflavone (DHF) were constitutive of a polymer matrix and showed a high drug-loading rate (47.18%) and encapsulation efficiency (67.65%) with a theoretical release time of approximately 120 d. Cyanobacterial growth tests showed that the DHF beads had long-term inhibition effects (>30 d), whereas those of "direct-added" DHF to cells lasted a maximum of 10 d. The beads also continuously affected the superoxide dismutase, catalase, and lipid peroxidation of M. aeruginosa. The inhibitory effects of DHF beads on cyanobacterial growth increased as initial cell densities of M. aeruginosa decreased, suggesting that the beads inhibit cyanobacterial activity more effectively in the early bloom phase. Consequently, the anti-cyanobacterial beads represent a novel application mode of allelochemicals with long-term inhibitory effects on cyanobacterial growth. Our study demonstrates that the successful application of allelochemicals offers great potential to control harmful cyanobacterial blooms, especially at the initial stage of development. PMID:26986500

  16. 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. PMID:18814656

  17. 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

  18. Influence ofAmaranthus hybridus L. allelochemics on oviposition behavior ofSpodoptera exigua andS. eridania (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Mitchell, E R; Heath, R R

    1985-05-01

    Common pigweed,Amaranthus hybridus L., is a favorite host of the beet army worm (BAW),Spodoptera exigua L. Chemicals extracted from homogenized pigweed with distilled water, ethanol, or dichloromethane and sprayed back on pigweed deterred oviposition by the BAW. Similarly, water extracts of frass from conspecific larvae or southern armyworm (SAW) larvae,S. eridania (Cramer), fed pigweed leaves and sprayed back on pigweed plants also deterred BAW oviposition, thus confirming that deterrence was due to plant allelochemics rather than specific compounds associated with the metabolic or excretory products of the larvae. Confirmation of the presence of oviposition-deterring chemicals in pigweed was used to explain a previously observed seasonal displacement of BAW by SAW on pigweed in the field. PMID:24310126

  19. Soil microorganisms alleviate the allelochemical effects of a thyme monoterpene on the performance of an associated grass species.

    Directory of Open Access Journals (Sweden)

    Bodil K Ehlers

    Full Text Available BACKGROUND: Plant allelochemicals released into the soil can significantly impact the performance of associated plant species thereby affecting their competitive ability. Soil microbes can potentially affect the interaction between plant and plant chemicals by degrading the allelochemicals. However, most often plant-plant chemical interactions are studied using filter paper bioassays examining the pair-wise interaction between a plant and a plant chemical, not taking into account the potential role of soil microorganisms. METHODOLOGY/PRINCIPAL FINDINGS: To explore if the allelopathic effects on a grass by the common thyme monoterpene "carvacrol" are affected by soil microorganisms. Seedlings of the grass Agrostis capillaris originating from 3 different thyme sites were raised in the greenhouse. Seedlings were grown under four different soil treatments in a 2*2 fully factorial experiment. The monoterpene carvacrol was either added to standard greenhouse soil or left out, and soil was either sterilized (no soil microorganisms or not (soil microorganisms present in soil. The presence of carvacrol in the soil strongly increased mortality of Agrostis plants, and this increase was highest on sterile soil. Plant biomass was reduced on soil amended with carvacrol, but only when the soil was also sterilized. Plants originating from sites where thyme produces essential oils containing mostly carvacrol had higher survival on soil treated with that monoterpene than plants originating from a site where thyme produced different types of terpenes, suggesting an adaptive response to the locally occurring terpene. CONCLUSIONS/SIGNIFICANCE: The study shows that presence of soil microorganisms can alleviate the negative effect of a common thyme monoterpene on the performance of an associated plant species, emphasizing the role of soil microbes in modulating plant-plant chemical interactions.

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

    OpenAIRE

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

    2015-01-01

    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 re...

  1. The Use of Bio-Guided Fractionation to Explore the Use of Leftover Biomass in Dutch Flower Bulb Production as Allelochemicals against Weeds

    Directory of Open Access Journals (Sweden)

    Rob Verpoorte

    2013-04-01

    Full Text Available 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.

  2. 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

    2015-01-01

    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. PMID:26393579

  3. 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

  4. 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

  5. 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. PMID:27079356

  6. Preliminary characterization of extracellular allelochemicals of the toxic marine dinoflagellate Alexandrium tamarense using a Rhodomonas salina bioassay.

    Science.gov (United States)

    Ma, Haiyan; Krock, Bernd; Tillmann, Urban; Cembella, Allan

    2009-01-01

    Members of the marine dinoflagellate genus Alexandrium are known to exude allelochemicals, unrelated to well-known neurotoxins (PSP-toxins, spirolides), with negative effects on other phytoplankton and marine grazers. Physico/chemical characterization of extracellular lytic compounds of A. tamarense, quantified by Rhodomonas salina bioassay, showed that the lytic activity, and hence presumably the compounds were stable over wide ranges of temperatures and pH and were refractory to bacterial degradation. Two distinct lytic fractions were collected by reversed-phase solid-phase extraction. The more hydrophilic fraction accounted for about 2% of the whole lytic activity of the A. tamarense culture supernatant, while the less hydrophilic one accounted for about 98% of activity. Although temporal stability of the compounds is high, substantial losses were evident during purification. Lytic activity was best removed from aqueous phase with chloroform-methanol (3:1). A "pseudo-loss" of lytic activity in undisturbed and low-concentrated samples and high activity of an emulsion between aqueous and n-hexane phase after liquid-liquid partition are strong evidence for the presence of amphipathic compounds. Lytic activity in the early fraction of gel permeation chromatography and lack of activity after 5 kD ultrafiltration indicate that the lytic agents form large aggregates or macromolecular complexes. PMID:20098594

  7. Preliminary Characterization of Extracellular Allelochemicals of the Toxic Marine Dinoflagellate Alexandrium tamarense Using a Rhodomonas salina Bioassay

    Directory of Open Access Journals (Sweden)

    Allan Cembella

    2009-11-01

    Full Text Available Members of the marine dinoflagellate genus Alexandrium are known to exude allelochemicals, unrelated to well-known neurotoxins (PSP-toxins, spirolides, with negative effects on other phytoplankton and marine grazers. Physico/chemical characterization of extracellular lytic compounds of A. tamarense, quantified by Rhodomonas salina bioassay, showed that the lytic activity, and hence presumably the compounds were stable over wide ranges of temperatures and pH and were refractory to bacterial degradation. Two distinct lytic fractions were collected by reversed-phase solid-phase extraction. The more hydrophilic fraction accounted for about 2% of the whole lytic activity of the A. tamarense culture supernatant, while the less hydrophilic one accounted for about 98% of activity. Although temporal stability of the compounds is high, substantial losses were evident during purification. Lytic activity was best removed from aqueous phase with chloroform-methanol (3:1. A “pseudo-loss” of lytic activity in undisturbed and low-concentrated samples and high activity of an emulsion between aqueous and n-hexane phase after liquid-liquid partition are strong evidence for the presence of amphipathic compounds. Lytic activity in the early fraction of gel permeation chromatography and lack of activity after 5 kD ultrafiltration indicate that the lytic agents form large aggregates or macromolecular complexes.

  8. Effects of allelochemicals from first (brassicaceae) and second (Myzus persicae and Brevicoryne brassicae) trophic levels on Adalia bipunctata.

    Science.gov (United States)

    Francis, F; Lognay, G; Wathelet, J P; Haubruge, E

    2001-02-01

    Three Brassicaceae species, Brassica napus (low glucosinolate content), Brassica nigra (including sinigrin), and Sinapis alba (including sinalbin) were used as host plants for two aphid species: the generalist Myzus persicae and the specialist Brevicoryne brassicae. Each combination of aphid species and prey host plant was used to feed the polyphagous ladybird beetle, Adalia bipunctata. Experiments with Brassicaceae species including different amounts and kinds of glucosinolates (GLS) showed increased ladybird larval mortality at higher GLS concentrations. When reared on plants with higher GLS concentrations, the specialist aphid, B. brassicae, was found to be more toxic than M. persicae. Identification of GLS and related degradation products, mainly isothiocyanates (ITC), was investigated in the first two trophic levels, plant and aphid species, by high-performance liquid chromatography and gas chromatography-mass spectrometry, respectively. While only GLS were detected in M. persicae on each Brassicaceae species, high amounts of ITC were identified in B. brassicae samples (allyl-ITC and benzyl-ITC from B. nigra and S. alba, respectively) from all host plants. Biological effects of allelochemicals from plants on predators through aphid prey are discussed in relation to aphid species to emphasize the role of the crop plant in integrated pest management in terms of biological control efficacy. PMID:14768813

  9. 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. PMID:23572390

  10. Plant allelochemicals and insect parasitoids effects of nicotine onCotesia congregata (say) (Hymenoptera: Braconidae) andHyposoter annulipes (Cresson) (Hymenoptera: Ichneumonidae).

    Science.gov (United States)

    Barbosa, P; Saunders, J A; Kemper, J; Trumbule, R; Olechno, J; Martinat, P

    1986-06-01

    Parasitoids developing within tobacco hornworms or fall army-worms exhibit significant differences in development and survival depending on whether their hosts fed on nicotine-free or nicotine-containing diets. The effects of nicotine were more severe on the relatively less adapted parasitoid,H. annulipes than the specialist parasitoid,Cotesia congregata. Labeled alkaloid originally placed in herbivore diet was incorporated in several parasitoid tissues. These results suggest that interactions between plant allelochemicals and parasitoids should be considered in the development of theory on insect herbivory and plant defense. PMID:24307111

  11. Mechanism and Active Variety of Allelochemicals%植物化感物质活性变化及其作用机理研究进展

    Institute of Scientific and Technical Information of China (English)

    彭少麟; 文军; 郭勤峰

    2004-01-01

    本文综述了化感物质活性的变化、变化的原因及其功能机理.化感物质活性在自然过程中,由于温度、光周期、水和土壤等的不同而变化,在功能过程中随其初始浓度、化合物结构和混合程度不同而变化,在植物体内由于组织器官和成熟程度不同而变化,而研究技术和操作过程也影响化感物质的活性.文章还讨论了未来化感作用研究的发展方向.未来化感作用研究将集焦于如下五方面:(1)更有效地在实践中,特别是在农业生产过程中鉴定和提纯化感物质;(2)化感作用在分子结构水平的功能定位;(3)应用化感作用解释植物种间相互作用;(4)化感作用在植被演替过程中的驱动力作用;(5)化感作用在进化过程中的意义.%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.

  12. 大蒜根系分泌物化感作用及化感物质的比较%Comparative analysis of allelopathy and allelochemicals of the root exudates in garlic

    Institute of Scientific and Technical Information of China (English)

    周艳丽; 程智慧

    2012-01-01

    【目的】利用生物测定和GC-MS分析方法,研究大蒜根系分泌物的化感作用及化感物质。【方法】采用琼脂培和砂培2种栽培方式收集大蒜根系分泌物,分别采用乙醚、乙酸乙酯、三氯甲烷和正丁醇4种有机溶剂进行萃取分离,对各有机溶剂萃取液进行萝卜种子发芽试验,确定出强化感作用组分,并对其成分进行GC-MS分析。【结果】各有机溶剂萃取液的化感作用强弱顺序依次为:乙酸乙酯萃取液〉三氯甲烷萃取液〉正丁醇和乙醚萃取液,初步确定大蒜根系分泌物中的化感物质为2,6-二异丙基苯酚、2,6-二叔丁基对甲酚和二烯丙基二硫醚。【结论】2种栽培方式收集的大蒜根系分泌物的乙酸乙酯组分中的成分相似,但在含量上差异较大,表现为砂培〉琼脂培。%【Objective】 The allelopathy and major allelochemicals in root exudates of garlic were studied by bioassay and GC-MS methods.【Method】 The root exudates of garlic were collected from agar culture and sand culture in this experiment,and were extracted by ethyl ether,ethyl acetate,chloroform and n-butanol.【Result】 The results showed that allelopathy of ethyl acetate component was the strongest,followed by chloroform component,the allelopathy of ethyl ether component and n-butanol component.The component of ethyl acetate was analyzed by GC-MS,and the main allelochemicals were identified as 2,6-bis(1-methylethyl)-phenol,butylated hydroxytoluene and diallyl disulphide.【Conclusion】 The allelochemicals were similar in ethyl acetate fraction of two cultivation forms,but the quantity was different,and the varieties and quantities of allelochemicals in sand culture were higher than agar culture.

  13. 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.

  14. 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.

  15. 凤眼莲化感物质对铜绿微囊藻、斜生栅藻生长及细胞数相对比例的影响%Effects of Eichhornia crassipes allelochemicals on the growth of two mono-and co-cultured algae Microcystis aeruginosa and Scenedesmus obliquus

    Institute of Scientific and Technical Information of China (English)

    刘光涛; 周长芳; 孙利芳; 朱薇薇; 姜昊; 王涵兴; 安树青

    2011-01-01

    To explore the possibility of using allelochemicals in solving the problem of algal blooms in eutrophicated shallow lakes,five allelochemicals found from roots of Eichhornia crassipes(linoleic acid,1-linoleoyl-rac-glycerol,propionamide,N-phenyl-2-naphthylamine and nonanoic acid) were tested with mono-and co-cultured algae Microcystis aeruginosa and Scenedesmus obliquus.The results showed that components and doses of the allelochemicals,as well as culture modes,affected the growth of the two algae significantly(p 0.001).The allelochemicals generally promoted the growth of the algae when added at low concentrations(0.1 ~ 1.0 mg.L-1) and during early culture stages,while such effects turned into inhibition when allelochemical concentration was increased(10.0 mg.L-1) and the culture stage was extended.Among the fived allelochemicals tested,nonanoic acid had the strongest effect on both algae,whereas individually,M.aeruginosa was most affected by propionamide,and S.obliquus by linoleic acid.Cell number proportions of S.obliquus in co-cultures were also increased by nonanoic acid at a concentration of 0.1 ~ 1.0 mg.L-1 and the other allelochemicals at 10.0 mg.L-1(p 0.05).This research indicated a promising potential of the application of Eichhornia crassipes allelochemicals in control of aquatic algae.%为探索化感物质在蓝藻水华治理方面的应用潜力,选取在凤眼莲根系分泌物中发现的5种化感物质(亚油酸、亚油酸甘油酯、丙酰胺、N-苯基—2-萘胺和壬酸),研究了3种剂量下(0.1、1.0、10.0mg.L-1)其对单一、混合培养铜绿微囊藻和斜生栅藻生长的影响.结果发现,化感物质成分、剂量和藻类培养方式对铜绿微囊藻和斜生栅藻生长都具有极显著的影响(p〈0.001),化感物质剂量相对而言影响力最大.5种化感物质对两种藻类的生长总体上呈低剂量促进高剂量抑制和先促进后抑制的趋势.其中,壬酸对两种藻

  16. 不同暴露方式下水生植物化感物质抑藻效应的比较研究%Comparative Study on Antialgal Effects of Allelochemicals from Aquatic Plants under Different Exposure Protocols

    Institute of Scientific and Technical Information of China (English)

    高云霓; 葛芳杰; 刘碧云; 鲁志营; 何燕; 张甬元; 吴振斌

    2015-01-01

    为研究水生植物释放的化感物质在生态水平上的有效作用模式,选择水生植物释放的壬酸、N-苯基-1-萘胺和咖啡酸等不同类型化感物质,比较高剂量单次暴露与低剂量多次暴露对铜绿微囊藻(Microcystis aeruginosa)生长的影响,探讨化感物质不同投加频次、剂量和光暗条件等对多次暴露抑藻效果的影响。结果显示,3种化感物质以2 h为间隔、分5次、每次添加0.5 mg·L-1的方式暴露时均表现出比以总剂量2.5 mg·L-1单次暴露更强的抑藻效果,在实验的第7天壬酸、N-苯基-1-萘胺和咖啡酸的抑藻率是单次暴露组的1.8、1.1和1.6倍。以1 h间隔、10次暴露的壬酸和N-苯基-1-萘胺,抑制率随着单次添加量的减少而降低,但在单次暴露剂量低至0.1 mg·L-1时两种物质仍能显著抑制铜绿微囊藻的生长,第7天N-苯基-1-萘胺的平均生长抑制率仍可以达到50.25%。壬酸和N-苯基-1-萘胺在铜绿微囊藻生长的黑暗阶段多次暴露比在光照阶段的抑藻效果好,第3天的平均抑制率分别是是光照阶段的2.2和1.3倍。上述结果表明,水生植物释放的化感物质可以通过低剂量多次暴露实现比高剂量单次暴露更强的抑藻效果。因此,加强对化感物质多次暴露方式下抑藻作用的研究将推动自然环境中水生植物化感作用生态机制的进一步揭示,有利于指导水生植物化感作用的理论研究和实践应用。%To explore the effective pathway of how the allelochemicals released by aquatic plants work at ecological levels, three typical allelochemicals including nonanoic acid, N-phenyl-1-naphthylamine and caffeic acid, from different chemical classes, were selected to compare their inhibition effects at high-dose single exposure and low-dose repeated exposure on the growth of Microcystis aeruginosa. The influences of exposure frequency, dose and light conditions on the repeated exposure

  17. 嫁接西瓜根系分泌物的化感效应及其化感物质的鉴定%Allelopathic effects and identification of allelochemicals in root exudates of grafted watermelons

    Institute of Scientific and Technical Information of China (English)

    郑阳霞; 唐海东; 李焕秀; 严泽生; 郭学君

    2011-01-01

    In order to study the allelopathic effects of root exudates from the watermelons grafted with pumpkin and calabash as rootstocks,effects of root exudates from the watermelons grafted on the seed germination and seedling growth of watermelons were researched.The Allelochemicals of root exudates were detected by GC-MS.The results showed that the seed germination and seedling growth of watermelons were increased when the root exudates were in low concentration,but decreased in high concentration.The root exudates promoted the seed germination and seedling growth of watermelons at 2.5 μL·L-1.The root exudates began to restrain the seed germination and seedling growth of watermelons at 10 μL·L-1.When the concentrations were lower,the root exudates from grafted watermelons had more effects on the seed germination and seedling vegetal promotion than own-rooted watermelons.The inhibiting effect of grafted watermelons was less than that of own-rooted watermelon at high concentration of root exudates.And the identification of the allelochemicals in root exudates of grafted watermelons indicated that the categories and the relative contents were different from the own-root plants.The results showed that grafting changed the categories and the relative contents of root exudate components and changed allelopathic effects.Furthermore,there was obvious grafting superiority.So grafting was one of the effective methods for relieving the continuous cropping obstacles caused by autotoxicity.%为了研究嫁接西瓜根系分泌物的化感效应,采用南瓜、葫芦作砧木嫁接西瓜,研究了嫁接西瓜根系分泌物对西瓜种子萌发和幼苗生长的影响,并对嫁接西瓜根系分泌物中的化感物质进行了GC-MS检测。结果表明,各处理对西瓜种子发芽和幼苗生长均呈现出低促高抑的规律。在根系分泌物浓缩液浓度为2.5μL.L-1时,促进西瓜种子的发芽和幼苗的生长。在浓度为10μL.L-1、20μL.L-1

  18. Role of allelochemicals and trichome density in the resistance of tomato to whitefly Papel de aleloquímicos e densidade de tricomas na resistência de tomateiro à mosca-branca

    Directory of Open Access Journals (Sweden)

    Irã Pinheiro Neiva

    2013-02-01

    Full Text Available In Brazil, the tomato is cultivated in almost all geographic regions even though its yield is significantly reduced by pests and diseases. Among these pests and diseases, whitefly is a major problem that causes direct and indirect damage due to its role in transmission of geminiviruses. The aim of the present study was to compare the degree of resistance to the silverleaf whitefly of tomato plant lines rich in acyl sugars (AS, zingiberene (ZGB, and 2-tridecanone (2-TD and to establish whether selection for strains with higher densities of glandular trichomes promotes sufficient resistance to this insect pest. The investigated lines were developed by performing back-crossings in tomato (Solanum lycopersicum from the interspecific crossing of S. lycopersicum x S. habrochaites var. glabratum 'PI 134417'. Lines rich in AS, ZGB, and 2-TD were tested for their levels of resistance to B. tabaci biotype B. Two tomato plant lines (TOM-584 and TOM-679 with normal AS levels and one wild specimen (PI 134417 with high 2-TD content were used as controls. TOM-687, ZGB-703, and TOM-622 were less preferred by B. tabaci for oviposition, and nymphs exhibited a poorer survival rate on those plant lines than on the susceptible controls, TOM-584 and TOM-679. Allelochemical-rich lines exhibited pest resistance, whereas the controls did not, and the allelochemical-rich lines did not differ significantly from each other in the level of resistance. The results show that the development of tomato plant lines rich in 2-TD, ZGB and AS is an effective option for indirect selection for resistance to B. tabaci biotype B. All lines selected based on high trichome density except for BPX-365F-751-05-01-03 exhibited fewer nymphs than the susceptible controls, indicating that selection for more glandular trichomes was generally effective in promoting increased resistance to the silverleaf white flay.No Brasil, o tomate é cultivado em praticamente todas as regiões, embora seu

  19. 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

  20. Allelochemical phenolic acids from Gypsophila paniculata

    Science.gov (United States)

    Bioassay-guided fractionation of Gypsophila paniculata L. (Caryophyllaceae) resulted in the isolation of the phenolics p-coumaric acid (1), dihydroferulic acid (2), and syringic acid (3). In addition to their noted weak antimicrobial activity, compounds 1 and 3 are known to be potent exuded alleloc...

  1. 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.

  2. Syntheses of Allelochemicals for Insect Control

    OpenAIRE

    Smitt, Olof

    2002-01-01

    This thesis describes the synthetic preparation of somecompounds, which can serve as chemical signals for use in thedevelopment of control methods for pest insects. The compoundssynthesised are of the isoprenoid type and of two kinds:carvone derivatives and germacranes. The derivatives of carvoneare based on modifications of this compound, by reactions ofeither its endocyclic or its exocyclic double bond. One type ofmodifications was accomplished by chemoselective additions ofthiophenol. The ...

  3. Physiological Conjunction of Allelochemicals and Desert Plants

    OpenAIRE

    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...

  4. Synergistic allelochemicals from a freshwater cyanobacterium

    OpenAIRE

    Pedro N. Leão; Pereira, Alban R.; Liu, Wei-Ting; Ng, Julio; Pevzner, Pavel A; Dorrestein, Pieter C.; König, Gabriele M.; Vasconcelos, Vitor M.; Gerwick, William H

    2010-01-01

    The ability of cyanobacteria to produce complex secondary metabolites with potent biological activities has gathered considerable attention due to their potential therapeutic and agrochemical applications. However, the precise physiological or ecological roles played by a majority of these metabolites have remained elusive. Several studies have shown that cyanobacteria are able to interfere with other organisms in their communities through the release of compounds into the surrounding medium,...

  5. 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

  6. Potential allelochemicals from the essential oil of Ruta graveolens.

    Science.gov (United States)

    De Feo, Vincenzo; De Simone, Francesco; Senatore, Felice

    2002-11-01

    The essential oil of aerial parts of Ruta graveolens was obtained by hydrodistillation with a 0.74% yield on a dry weight basis. Thirty-eight components were identified by GC and GC-MS analyses. 2-Ketones predominated in the essential oil, with undecan-2-one (46.8%) and nonan-2-one (18.8%) as the main constituents. The essential oil and some of its constituents were tested for their allelopathic activity in vitro on radish germination and radicle growth in light and darkness. The essential oil and some of its minor constituents were effective and dose-dependent inhibitors of both the germination and radicle growth; 2-ketones are not active. The possible allelopathic activity of rue essential oil and some its isolated constituents is reported. PMID:12409025

  7. Allelochemicals in plants and the use of allelopathy in agronomy

    OpenAIRE

    Paulo Sérgio Siberti da Silva

    2012-01-01

    Within the plant kingdom, allelopathy occurs in forests and in agroecosystems, which can produce beneficial or harmful effects on plants that are related to the release of secondary metabolites. This phenomenon influences the formation of plant communities in natural environments and also serves as an important tool in agronomy because it can be used to control undesirable plants, maintain healthy cultures, and can help save failing crops. Furthermore, allelopathic bioassays contribute to the...

  8. Potential allelochemicals from an invasive weed Mikania micrantha H.B.K.

    Science.gov (United States)

    Shao, Hua; Peng, Shaolin; Wei, Xiaoyi; Zhang, Deqing; Zhang, Chi

    2005-07-01

    Phytotoxicity-directed extraction and fractionation of the aerial parts of Mikania micrantha H.B.K. led to the isolation and identification of three sesquiterpenoids: dihydromikanolide, deoxymikanolide, and 2,3-epoxy-1-hydroxy-4,9-germacradiene-12,8:15,6-diolide. These sesquiterpenoids inhibited both germination and seedling growth of tested species with deoxymikanolide possessing the strongest phytotoxicity. In a bioassay against lettuce (Lectuca sativa L.), deoxymikanolide reduced radicle elongation at low concentration (IC50 = 47 microg/ml); dihydromikanolide showed a weaker effect (IC50 = 96 microg/ml), and 2,3-epoxy-1-hydroxy-4,9-germacradiene-12,8:15,6-diolide exhibited the least effect (IC50 = 242 microg/ml). Deoxymikanolide caused yellowish lesions at the root tips of lettuce at a concentration of 50 microg/ml, and a 250 microg/ml solution killed lettuce seedlings. A bioassay against the monocot ryegrass (Lolium multiforum) revealed similar results on radicle elongation, which implied that the growth inhibition by these compounds was not selective. To evaluate their phytotoxicity to plants in natural habitats, three common companion tree species in south China, Acacia mangium, Eucalyptus robusta, and Pinus massoniana, were also tested and similar results were obtained. This is the first report on the isolation of 2,3-epoxy-1-hydroxy-4,9-germacradiene-12,8:15,6-diolide as a naturally occurring product. PMID:16222800

  9. Role of avian trigeminal sensory system in detecting coniferyl benzoate, a plant allelochemical.

    Science.gov (United States)

    Jakubas, W J; Mason, J R

    1991-11-01

    Coniferyl benzoate, a secondary metabolite found in quaking aspen (Populus tremuloides) and other plants, is an avian feeding deterrent of ecological and potential commercial importance. This study was conducted to determine if coniferyl benzoate is a trigeminal stimulant for birds and to ascertain if trigeminal chemoreception of coniferyl benzoate can mediate avian feeding behavior. Five European starlings (Sturnus vulgaris) with bilateral nerve cuts (ophthalmic branch of the trigeminal nerve) and four starlings that had sham surgeries were fed a commercial diet treated with coniferyl benzoate. Birds receiving bilateral nerve cuts ate significantly more feed than intact birds, indicating trigeminal detection of coniferyl benzoate and trigeminal mediation of feeding behavior. In the past, trigeminal chemoreception has not been recognized as important in the detection of plant secondary metabolites despite the irritant or astringent properties of a number of them. PMID:24258600

  10. 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. PMID:24974850

  11. Induction by carrot allelochemicals of insecticide-metabolising enzymes in the southern armyworm (Spodoptera eridania).

    Science.gov (United States)

    Brattsten, L B; Evans, C K; Bonetti, S; Zalkow, L H

    1984-01-01

    Carrot foliage monoterpenes induce cytochrome P-450 up to 2.9-fold, NADPH cytochrome c (P-450) reductase up to 1.6-fold, NADPH-oxidation up to 3.8-fold, aldrin epoxidation up to 1.5-fold in southern armyworm larval midgut tissues when incorporated in their diet at 0.2% for 3 days. Stigmasterol and ergosterol did not substantially induce microsomal oxidase activities and significantly inhibited GSH S-aryltransferase activity and sulfotransferase activity. Coumarin did not substantially affect microsomal oxidase and sulfotransferase activity but is the most potent inducer of GSH S-aryltransferase activity, increasing this activity 7-fold. None of the chemicals is acutely toxic to the sixth instar larvae or affect the larval weight gain except coumarin which significantly depressed the maximal body weight attained. PMID:6141878

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

    OpenAIRE

    R. N. Yadava* and Shirin Khan

    2013-01-01

    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...

  13. Do phytotoxic allelochemicals remain in ashes after burning Chrysanthemoides monilifera subsp. monilifera (boneseed)?

    Science.gov (United States)

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

    2016-06-01

    Australia is facing challenges in controlling Chrysanthemoides monilifera subsp. monilifera (boneseed). However, burning has achieved some success in this regard. We aimed to investigate the comparative phytotoxicity of boneseed dried powder and ashes (burnt at 450°C and 250°C). Phenolic compounds in powder and ashes were measured using Folin-Ciocalteu assay and HPLC. The phytotoxicity of boneseed powder and ash extracts was assessed through germination bioassay on Lactuca sativa and the phytotoxicity of litter and ashes was evaluated using field soil, both in growth chamber. Burning of boneseed reduced total phenolics in ashes of boneseed organs by 99% and 100% both at high and low temperatures. The four phenolic compounds that were detected in boneseed were either absent or at negligible levels in the ashes, with inversely related to temperature. Both boneseed ash extracts and litter ash-mediated soil significantly reduced phytotoxicity displaying increased germination, biometric and biochemical parameters of test species compared with unburnt powder extracts and litter powder-mediated soil respectively, with greater reduction of phytotoxicity found for ashes produced at the lower temperature. Interestingly, the ash extracts and litter ash-mediated soil were found to stimulate some of those parameters of the test species compared to control. There was no excessive reactive oxygen species (ROS) produced in test species exposed to ash extracts compared with unburnt powder extracts. These findings suggest that burning of boneseed is an appropriate method of weed control and that this approach will reduce phytotoxicity of this species on native plants. PMID:27266307

  14. Allelopathy in benthic and littoral areas : case studies on allelochemicals from benthic cyanobacteria and submersed macrophytes

    OpenAIRE

    Gross, Elisabeth

    1999-01-01

    Photosynthetic organisms in littoral and benthic habitats are in general situated in close proximity to their competitors. Benthic algae and cyanobacteria compete for space and grow adjacent to each other. Submersed macrophytes can be overgrown by epiphytic algae and are surrounded by other macrophytes and phytoplankton. The particular spatial setup in these habitats makes allelopathy a powerful strategy. Released compounds can more or less directly reach and act on target organisms. Allelopa...

  15. Metabolomics differentiation of canola genotypes: toward an understanding of canola allelochemicals

    OpenAIRE

    Asaduzzaman, M.; Pratley, James E.; An, Min; Luckett, David J.; Lemerle, Deirdre

    2015-01-01

    Allelopathy is one crop attribute that could be incorporated in an integrated weed management system as a supplement to synthetic herbicides. However, the underlying principles of crop allelopathy and secondary metabolite production are still poorly understood including in canola. In this study, an allelopathic bioassay and a metabolomic analysis were conducted to compare three non-allelopathic and three allelopathic canola genotypes. Results from the laboratory bioassay showed that there wer...

  16. Costs and benefits of plant allelochemicals in herbivore diet in a multi enemy world.

    Science.gov (United States)

    Reudler, J H; Lindstedt, C; Pakkanen, H; Lehtinen, I; Mappes, J

    2015-12-01

    Sequestration of plant defensive chemicals by herbivorous insects is a way of defending themselves against their natural enemies. Such herbivores have repeatedly evolved bright colours to advertise their unpalatability to predators, i.e. they are aposematic. This often comes with a cost. In this study, we examined the costs and benefits of sequestration of iridoid glycosides (IGs) by the generalist aposematic herbivore, the wood tiger moth, Parasemia plantaginis. We also asked whether the defence against one enemy (a predator) is also effective against another (a parasitoid). We found that the larvae excrete most of the IGs and only small amounts are found in the larvae. Nevertheless, the amounts present in the larvae are sufficient to deter ant predators and also play a role in defence against parasitoids. However, excreting and handling these defensive plant compounds is costly, leading to longer development time and lower pupal mass. Interestingly, the warning signal efficiency and the amount of IGs in the larvae of P. plantaginis are negatively correlated; larvae with less efficient warning signals contain higher levels of chemical defence compounds. Our results may imply that there is a trade-off between production and maintenance of coloration and chemical defence. Although feeding on a diet containing IGs can have life-history costs, it offers multiple benefits in the defence against predators and parasitoids. PMID:26296333

  17. Naphthoquinone spiroketal with allelochemical activity from the new endophytic fungus Edenia gomezpompae

    Science.gov (United States)

    Bioassay-guided isolation from the culture of Edenia gomezpompae, a new endophytic fungus isolated from the leaves of Callicarpa acuminata (Verbenaceae) from the ecological reserve El Eden, Quintana Roo, Mexico, led to the isolation of four naphthoquinone spiroketals, including three new compounds. ...

  18. Rumex obtusifolius L: Release of allelochemical agents and their influence on small-scale spatial distribution of meadow species.

    Science.gov (United States)

    Carral, E; Reigosa, M J; Carballeira, A

    1988-09-01

    DecomposingRumex obtusifolius L. leaves and their extracts were most toxic for germination and root growth of meadow speciesLolium perenne, Trifolium repens, Poa pratensis, andDactylis glomerata after seven days' decomposition, although the toxicity level was, in some cases, still high after 21 days. The hypothesis thatR. obtusifolius exerts allelopathic control over meadow species is supported by small-scale distribution of meadow species in the neighborhood ofR. obtusifolius plants. The area affected and the intensity of the effect both increase with the size of the individualR. obtusifolius plant. PMID:24276532

  19. EFFECT OF ALLELOCHEMICALS FROM CRESSA CRETICA L. ON IN VITRO POLLEN GERMINATION OF CAJANUS CAJAN (L. MILL SP

    Directory of Open Access Journals (Sweden)

    Kumbhar B. A.1 and Patel G. R. 2

    2012-06-01

    Full Text Available Cressa cretica L. belonging to family Convolvulaceae, commonly known as Boknu is a erect, small, dwarf shrub, usually grows in sandy or muddy saline habitats. Brew baker and Kwack's basal medium was used for germination of pollen grains. At low concentration (5% and 10% of water extract of Cressa cretica plant (WEC reported minimum inhibitory effect i.e., 57.84% 42.78% respectively on in vitro pollen germination of Cajanus cajan. The maximum reduced pollen germination was observed under 75% concentration of leaf extract (8.69% and pollens were no germinated on 100% of WEC as compared to control (70% after 15 minutes. The aerial parts of Cressa cretica L. yielded five flavonoids that were identified.

  20. 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. PMID:20211477

  1. 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.

  2. 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

  3. Tissue and Life Stage Specificity of Glutathione S-Transferase Expression in the Hessian Fly, Mayetiola destructor: Implications for Resistance to Host Allelochemicals

    OpenAIRE

    Mittapalli, Omprakash; Neal, Jonathan J.; Shukle, Richard H

    2007-01-01

    Two new Delta and Sigma glutathione S-transferases (GSTs) in the Hessian fly, Mayetiola destructor (Diptera: Cecidomyiidae), were characterized and transcription profiles described. The deduced amino acid sequences for the two M. destructor Delta GSTs (MdesGST-1 and MdesGST-3) showed high similarity with other insect Delta GSTs including the conserved catalytic serine residue. The deduced amino acid sequence for the M. destructor Sigma GST (MdesGST-2) showed high similarity with other insect ...

  4. 酚酸类化感物质抑藻作用的研究进展%RESEARCH PROGRESS ON THE INHIBITORY EFFECTS OF PHENOLIC ACID ALLELOCHEMICALS ON ALGAE

    Institute of Scientific and Technical Information of China (English)

    高李李; 郭沛涌

    2012-01-01

    阐述了酚酸类化感物质的分离与鉴定方法,探讨了酚酸对藻类的抑制作用机理及其藻类的响应.并对酚酸类化感物质用于工业水处理灭藻剂的前景进行了展望.酚酸对藻类的抑制作用机理包括对藻类细胞膜的破坏,对藻类多种酶活性与功能影响,对藻类光合作用与呼吸作用影响及对藻类基因表达的影响等方面.藻类对酚酸的累积与代谢作用使酚酸类化感物质残留较少,这使其开发为生态安全型灭藻剂成为可能.同时提出今后尚需从酚酸类化感物质的水环境行为与特性、生态安全性及抑藻特异性等方面做进一步深入研究.%This paper reviewed the methods of isolation and identification of phenolic acid compounds, their inhibition mechanism on algae, and the response of algae to phenolic acids. The prospects of phenolic acids applied as the aigicide of industrial water treatment were also discussed. The inhibition mechanisms of phenolic acids on algae included the damage of cell membrane, the impact on multi-enzyme activity and function, photosynthesis, respiration, gene expression, etc. The accumulation and metabolization of algae on phenolic acids made less residue, which made it possible to become a eco-fiiendly aigicide. Meanwhile, it suggested that it was necessary to keep on studying deeply the characters and actions, ecological safety and specificity of phenolic acids in aquatic environment.

  5. Allelic variation in the Depressaria pastinacella CYP6AB3 protein enhances metabolism of plant allelochemicals by altering a proximal surface residue and potential interactions with cytochrome P450 reductase.

    Science.gov (United States)

    Mao, Wenfu; Rupasinghe, Sanjeewa G; Zangerl, Arthur R; Berenbaum, May R; Schuler, Mary A

    2007-04-01

    CYP6AB3v1, a cytochrome P450 monooxygenase in Depressaria pastinacella (parsnip webworm), is highly specialized for metabolizing imperatorin, a toxic furanocoumarin in the apiaceous host plants of this insect. Cloning and heterologous expression of CYP6AB3v2, an allelic variant identified in D. pastinacella, reveals that it metabolizes imperatorin at a rate (V(max) of 10.02 pmol/min/pmol of cytochrome P450 monooxygenase (P450)) significantly higher than CYP6AB3v1 (V(max) of 2.41 pmol/min/pmol) when supplemented with even low levels of cytochrome P450 reductase. Comparisons of the NADPH consumption rates for these variants indicate that CYP6AB3v2 utilizes this electron source at a faster rate than does CYP6AB3v1. Molecular modeling of the five amino acid differences between these variants and their potential interactions with P450 reductase suggests that replacement of Val(92) on the proximal face of CYP6AB3v1 with Ala(92) in CYP6AB3v2 affects interactions with P450 reductase so as to enhance its catalytic activity. Allelic variation at this locus potentially allows D. pastinacella to adapt to both intraspecific and interspecific variation in imperatorin concentrations in its host plants. PMID:17244619

  6. Weeds Cause Losses in Field Crops through Allelopathy

    OpenAIRE

    Tasawer ABBAS; Tahira TABASSUM

    2016-01-01

    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 resid...

  7. 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...

  8. Phytochemical phytotoxins and hormesis - a commentary

    Science.gov (United States)

    The three papers (Hadacek et al., 2010; Liu et al., 2010; Sinkkonen et al., 2010) following this commentary are the result of an attempt by Regina Belz (Univ. Hohenheim) and me to generate a special issue dealing with dose-response aspects of allelochemicals. I use the term allelochemical to denote...

  9. The Emergence of Grass Root Chemical Ecology

    Science.gov (United States)

    This paper is an invited commentary on a paper to be published in this journal on the discovery of m-tyrosine as a potent allelochemical. Allelochemicals are natural herbicides produced by one type of plant to better compete with other plant species. In my commentary, I discuss the significance of...

  10. 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

  11. 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 biologica...

  12. Interactions between plants and microorganisms

    Science.gov (United States)

    Allelopathic microorganisms comprise rhizobacteria and fungi that colonize the surfaces of plant roots, and produce and release phytotoxic metabolites, similar to allelochemicals, that detrimentally affect growth of their host plants. The allelopathic microorganisms are grouped separately from typic...

  13. 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

    OpenAIRE

    Carlos Alberto Aragão; Bárbara França Dantas; Flávio Rodrigo Gandolfi Benites

    2002-01-01

    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 re...

  14. 水葫芦化感物质N-苯基-2-萘胺对铜绿微囊藻生长的影响%Effects of an allelochemical, N-phenyl-2-naphthylamine, from Eichhornia crassipes on the growth of Microcystis aeruginosa

    Institute of Scientific and Technical Information of China (English)

    耿小娟; 范勇; 王晓青; 傅华龙; 兰利琼

    2009-01-01

    以不同浓度的N-苯基-2-萘胺对铜绿微囊藻进行处理,研究铜绿微囊藻的生长曲线、叶绿素a的含量和抗氧化酶的活性.结果表明,N-苯基-2-萘胺对铜绿微囊藻的抑制效果比较明显,EC50,7d=5 mg/L、7 mg/L和10 mg/L的N-苯基-2-萘胺培养液在第10d抑制效果分别达到92.7%和96.8%.叶绿素a的含量随着培养液中N-苯基-2-萘胺浓度的升高而降低,在10 mg/L的培养液中,培养时间8 h和24 h的藻叶绿素a的含量与对照相比分别降低了67.4%和75.9%;超氧化物歧化酶、过氧化物酶和过氧化氢酶的活性都随着N-苯基-2-萘胺浓度的升高呈现先上升后下降的趋势,低浓度表现出促进作用,高浓度则表现出抑制作用.

  15. Phenolics and Plant Allelopathy

    OpenAIRE

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

    2010-01-01

    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 ...

  16. Cinnamic Acid Increases Lignin Production and Inhibits Soybean Root Growth

    OpenAIRE

    Victor Hugo Salvador; Rogério Barbosa Lima; Wanderley Dantas dos Santos; Anderson Ricardo Soares; Paulo Alfredo Feitoza Böhm; Rogério Marchiosi; Maria de Lourdes Lucio Ferrarese; Osvaldo Ferrarese-Filho

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean ( Glycine max ) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical in...

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

    OpenAIRE

    Tharayil, Nishanth

    2009-01-01

    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 ca...

  18. Allelopathy in Compositae plants. A review

    OpenAIRE

    Chon, S.-U.; Nelson, C J

    2010-01-01

    Allelopathy plays an major role in agricultural management such as weed control, crop protection, and crop re-establishment. Compositae plants have potent allelopathic activity, and the activity is confirmed through (a) bioassays with aqueous or various solvent extracts and residues, (b) fractionation, identification, and quantification of causative allelochemicals, and (c) mechanism studies on the allelochemicals. Most assessments of allelopathy involve bioassays of plant or soil extracts, l...

  19. Research on allelopathy in Portugal

    OpenAIRE

    Dias, L. S.; Pereira, I.P.; A. S. Dias

    1999-01-01

    The review shows that allelopathy is widespread in shrubs and trees of Portugal and hence, may play an important role in their ecology. The role of soil in the nature and intensity of allelopathy was demonstrated, and the potential of wheat straw and some aromatic plants to provide allelochemicals for herbicidal use has been found. Therefore, future lines of research should include I) the investigation of herbicidal potential of allelochemicals already identified in wheat straw, II) screening...

  20. Allelopathy in the Management of Plant-Parasitic Nematodes

    OpenAIRE

    Halbrendt, J. M.

    1996-01-01

    There are numerous reports of nematicidal chemicals in crude plant homogenates, leachates, and decomposing residues. These compounds are usually assumed to be secondary metabolites, which serve as chemical defenses against disease and parasites. When such compounds are released into the rhizosphere, they are known as allelochemicals. The possibility exists to exploit allelochemicals for nematode control, and there have been many attempts to use this approach either by rotation, intercropping,...

  1. The Impact of Microbial Biotransformation of Catechin in Enhancing the Allelopathic Effects of Rhododendron formosanum

    OpenAIRE

    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 i...

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

    OpenAIRE

    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 ...

  3. Allelopathic bacteria and their impact on higher plants.

    Science.gov (United States)

    Barazani, O; Friedman, J

    2001-01-01

    The impact of allelopathic, nonpathogenic bacteria on plant growth in natural and agricultural ecosystems is discussed. In some natural ecosystems, evidence supports the view that in the vicinity of some allelopathically active perennials (e.g., Adenostoma fasciculatum, California), in addition to allelochemicals leached from the shrub's canopy, accumulation of phytotoxic bacteria or other allelopathic microorganisms amplify retardation of annuals. In agricultural ecosystems allelopathic bacteria may evolve in areas where a single crop is grown successively, and the resulting yield decline cannot be restored by application of minerals. Transfer of soils from areas where crop suppression had been recorded into an unaffected area induced crop retardation without readily apparent symptoms of plant disease. Susceptibility of higher plants to deleterious rhizobacteria is often manifested in sandy or so-called skeletal soils. Evaluation of phytotoxic activity under controlled conditions, as well as ways to apply allelopathic bacteria in the field, is approached. The allelopathic effect may occur directly through the release of allelochemicals by a bacterium that affects susceptible plant(s) or indirectly through the suppression of an essential symbiont. The process is affected by nutritional and other environmental conditions, some may control bacterial density and the rate of production of allelochemicals. Allelopathic nonpathogenic bacteria include a wide range of genera and secrete a diverse group of plant growth-mediating allelochemicals. Although a limited number of plant growth-promoting bacterial allelochemicals have been identified, a considerable number of highly diversified growth-inhibiting allelochemicals have been isolated and characterized. Some species may produce more than one allelochemical; for example, three different phyotoxins, geldanamycin, nigericin, and hydanthocidin, were isolated from Streptomyces hygroscopicus. Efforts to introduce naturally

  4. 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.

  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. 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.

  7. Allelopathy in pigweed (a review

    Directory of Open Access Journals (Sweden)

    Pedro Luis da Costa Aguiar Alves

    2011-09-01

    Full Text Available Amaranthus spp. are plants with proven allelopathic potential. The release of allelochemicals from Amaranthus spp. in the environment can influence seed germination, photosynthesis rate, reduce growth and, consequently, the productivity of various plant species. Among the species with allelopathic potential are Amaranthus blitoides, Amaranthus gracilis, Amaranthus hybridus, Amaranthus palmeri, Amaranthus retroflexus, Amaranthus spinosus and Amaranthus viridis, with A. retroflexus being the most studied species and A. spinosus being the species with the greatest allelopathic potential. Due to the large quantities of allelochemicals produced by Amaranthus spp. these plants stand out as future suppliers of chemical molecules for bioherbicides and semisynthetic herbicides.

  8. Allelopathy in pigweed (a review)

    OpenAIRE

    Pedro Luis da Costa Aguiar Alves; Leonardo Bianco de Carvalho; Marcelo Claro de Souza; Paulo Roberto Fidelis Giancotti

    2011-01-01

    Amaranthus spp. are plants with proven allelopathic potential. The release of allelochemicals from Amaranthus spp. in the environment can influence seed germination, photosynthesis rate, reduce growth and, consequently, the productivity of various plant species. Among the species with allelopathic potential are Amaranthus blitoides, Amaranthus gracilis, Amaranthus hybridus, Amaranthus palmeri, Amaranthus retroflexus, Amaranthus spinosus and Amaranthus viridis, with A. retroflexus being the mo...

  9. 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...

  10. Experience-based behavioral and chemosensory changes in the generalist insect herbivore Helicoverpa armigera exposed to two deterrent plant chemicals

    NARCIS (Netherlands)

    Zhou, D.; Loon, van J.J.A.; Wang, C.Z.

    2010-01-01

    Behavioral and electrophysiological responses of larvae of the polyphagous moth species Helicoverpa armigera to two plant-derived allelochemicals were studied, both in larvae that had been reared on a diet devoid of these compounds and in larvae previously exposed to these compounds. In dual-choice

  11. 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; Olry, Alexandre; Kamo, Tsunashi; Taboureau, Olivier; Weitzel, Corinna; Bourgaud, Frederic; Hehn, Alain; Simonsen, Henrik Toft

    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 plant...

  12. 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...

  13. Associating rice root morphology and physiological traits with grain mineral concentrations of 24 varieties with extreme mineral compositions

    Science.gov (United States)

    The first step towards mineral accumulation in plant seeds is the absorption/uptake of minerals from the soil by roots. Root physiological activities, such as root respiration and metabolism, modify physical (soil temperature), chemical (soil pH, redox potential, root exudates, allelochemicals, and ...

  14. 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.

  15. Current Research Status of Allelopathy

    OpenAIRE

    AHMAD JUNAEDI; MUHAMMAD AHMAD CHOZIN; KWANG HO KIM

    2006-01-01

    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 screen...

  16. Study of Allelopathic Interaction of Wheat (Triticum Aestivum L. and Rye (Secale Cereal L. Using Equal-Compartment-Agar Method

    Directory of Open Access Journals (Sweden)

    M. Fariba

    2009-10-01

    Full Text Available There are many methods for weed management one of them is using allelopathy in weedmanagement programs. Equal-compartment-agar method was used for studying allelopathic interaction ofwheat and rye. In order to studying of sowing time (delayed sowing, synchronic sowing on allelopathicinteraction of wheat cultivars (Shiraz, Roshan, Tabasi, Niknejad and rye (Secale cereale on primary growthof rye and wheat, an experiment was done as factorial arrangement in a completely randomized design with4 replications. According to the results, the inhibitory effect of w heat on rye was more than in synchronicsowing, compared to delayed sowing. Roshan had the highest allelopathic potential on rye, compared to otherwheat cultivars. On the other hands, Roshan cultivar showed the highest sensitivity in the presence of rye. Rootlength showed the most sensitivity to released allelochemicals from wheat cultivars, because root has the mostcontact with allelochemicals.

  17. 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.

  18. 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. PMID:26530086

  19. Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors[OPEN

    Science.gov (United States)

    Venturelli, Sascha; Belz, Regina G.; Kämper, Andreas; Berger, Alexander; von Horn, Kyra; Wegner, André; Böcker, Alexander; Zabulon, Gérald; Barneche, Fredy; Lauer, Ulrich M.; Bitzer, Michael

    2015-01-01

    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. PMID:26530086

  20. Phytotoxic studies of medicinal plant species of Pakistan

    International Nuclear Information System (INIS)

    Allelopathic screening of 81 medicinal plant species, collected from North West Frontier Province (NWFP) Pakistan, was carried out to identify significantly higher allelopathic species for future phyto chemical analyses. For this purpose, sandwich method was used to test allelopathic potentials of leaf leachates of these plant species against lettuce seeds (Lactuca sativa L.). Two different concentrations of 10 mg and 50 mg of leaf leachates were used in the study. The radicle and hypocotyl growths were measured and compared with control treatments. It was observed that an endemic species Seriphidium kurramense, Andrachne cordifolia and Rhazya stricta were the stronger phyto toxic plants as compared to the other test species. Based on the current screening, three potential medicinal plants are recommended for future bioassay guided isolation of allelochemicals and for genetic diversity studies. It would also be interesting to see correlation between genetic markers and isolated allelochemicals. (author)

  1. Influence of barley straw and submerged macrophytes on fishpond wastewater quality

    OpenAIRE

    Ghobrial, M.G.; Okbah, M.A.; Gharib, S.M.; A. M. Soliman

    2007-01-01

    Barley straw has received, recently, considerable attention as an algicide, which could be used to control algal growth in fishponds. It is regarded as cost-effective, user friendly and environmentally sounds. On the other hand, the submerged wetland macrophytes are crucial for the stabilization of clear water state in shallow lakes, by their active production of anti-algal compounds (allelochemicals) through allelopathy. Microcosm experiments using barley straw and the submerged macrophytes:...

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

    OpenAIRE

    Shearer, TL; Rasher, DB; Snell, TW; Hay, ME

    2012-01-01

    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 survi...

  3. 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

  4. The Role of Detoxification Enzymes in Coral-Consuming Butterflyfish of Different Feeding Strategies From Hawaii and the Indo Pacific

    OpenAIRE

    Maldonado, Aileen

    2015-01-01

    A primary mechanism reef predators use to cope with dietary toxins is through detoxification. Detoxification enzyme cytochrome P450 (CYP) (specifically CYP3 and CYP2) was found in higher concentration in butterflyfish that preferentially feed on allelochemically rich corals. Butterflyfish (Chaetodon sp.) have unique feeding strategies with some species being generalist feeders and others feeding on several species of chemically-defended coral. This research elucidates the coevolutionary relat...

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

    OpenAIRE

    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 myco...

  6. Models Analyses for Allelopathic Effects of Chicory at Equivalent Coupling of Nitrogen Supply and pH Level on F. arundinacea, T. repens and M. sativa

    OpenAIRE

    Quanzhen Wang; Bao Xie; Chunhui Wu; Guo Chen; Zhengwei Wang; Jian Cui; Tianming Hu; Pawel Wiatrak

    2012-01-01

    Alllelopathic potential of chicory was investigated by evaluating its effect on seed germination, soluble sugar, malondialdehyde (MDA) and the chlorophyll content of three target plants species (Festuca arundinacea, Trifolium repens and Medicago sativa). The secretion of allelochemicals was regulated by keeping the donor plant (chicory) separate from the three target plant species and using different pH and nitrogen levels. Leachates from donor pots with different pH levels and nitrogen conce...

  7. Interactions of Bacillus Mojavensis and Fusarium Verticillioides With a Benzoxazolinone (Boa) and Its Transformation Product, Apo

    OpenAIRE

    Bacon, C.W.; Hinton, D M; Glenn, A. E.; Macías Domínguez, Francisco Antonio; Marín Mateos, David

    2007-01-01

    The benzoxazolinones, specifically benzoxazolin-2(3H)-one (BOA), are important transformation products of the benzoxazinones that can serve as allelochemicals providing resistance to maize from pathogenic bacteria, fungi, and insects. However, maize pathogens such as Fusarium verticillioides are capable of detoxifying the benzoxazolinones to 2-aminophenol (AP), which is converted to the less toxic N-(2-hydroxyphenyl) malonamic acid (HPMA) and 2-acetamidophenol (HPAA). As biocontrol strategies...

  8. Embryo growth, testa permeability, and endosperm weakening are major targets for the environmentally regulated inhibition of Lepidium sativum seed germination by myrigalone A

    Czech Academy of Sciences Publication Activity Database

    Voegele, A.; Graeber, K.; Oracz, K.; Tarkowská, Danuše; Jacquemoud, D.; Turečková, Veronika; Urbanová, Terezie; Strnad, Miroslav; Leubner-Metzger, G.

    2012-01-01

    Roč. 63, č. 14 (2012), s. 5337-5350. ISSN 0022-0957 R&D Projects: GA ČR GD522/08/H003; GA AV ČR KAN200380801 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional research plan: CEZ:AV0Z50380511 Keywords : Allelochemical * apoplastic superoxide * embryo growth Subject RIV: CE - Biochemistry Impact factor: 5.242, year: 2012

  9. Methods of collection of plant root exudates in relation to plant metabolism and purpose: A review

    Czech Academy of Sciences Publication Activity Database

    Vránová, V.; Rejšek, K.; Skene, K. R.; Janouš, Dalibor; Formanek, P.

    2013-01-01

    Roč. 176, č. 2 (2013), s. 175-199. ISSN 1436-8730 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:67179843 Keywords : allelochemical / CAM / C3 * C4 metabolism * retrieval * rhizodeposition * rhizosphere Subject RIV: EH - Ecology, Behaviour Impact factor: 1.663, year: 2013

  10. Feeding on resistant rice leads to enhanced expression of defender against apoptotic cell death (OoDAD1) in the Asian rice gall midge

    OpenAIRE

    Sinha, Deepak K.; Atray, Isha; Bentur, JS; Nair, Suresh

    2015-01-01

    Background The Asian rice gall midge (Orseolia oryzae) is a destructive insect pest of rice. Gall midge infestation in rice triggers either compatible or incompatible interactions leading to survival or mortality of the feeding maggots, respectively. In incompatible interactions, generation of plant allelochemicals/defense molecules and/or inability of the maggots to continue feeding on the host initiate(s) apoptosis within the maggots. Unraveling these molecular events, triggered within the ...

  11. Modeling the Effect of Density-Dependent Chemical Interference Upon Seed Germination

    OpenAIRE

    Sinkkonen, Aki

    2005-01-01

    A mathematical model is presented to estimate the effects of phytochemicals on seed germination. According to the model, phytochemicals tend to prevent germination at low seed densities. The model predicts that at high seed densities they may increase the probability of seed germination and the number of germinating seeds. Hence, the effects are reminiscent of the density-dependent effects of allelochemicals on plant growth, but the involved variables are germination probability and seedling ...

  12. Flavin-dependent monooxygenases as a detoxification mechanism in insects: new insights from the Arctiids (Lepidoptera)

    OpenAIRE

    Sehlmeyer, S.; Wang, L.(Universität Bochum, Institut für Experimentalphysik, Bochum, 44780, Germany); Langel, D.; Heckel, D.; Mohagheghi, H.; Petschenka, G.; Ober, D.

    2010-01-01

    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 (Le...

  13. Glutathione S-transferases of Aulacorthum solani and Acyrthosiphon pisum: partial purification and characterization.

    OpenAIRE

    Francis, Frédéric; Haubruge, Eric; Gaspar, Charles; Dierickx, P. J.

    2001-01-01

    Glutathione S-transferases (GST) play an important role in the detoxification of many substances including allelochemicals from plants. Brassicaceae plants contain glucosinolates and emit volatile isothiocyanates which affect the GST system. A comparison of the GST of two aphid species, the generalist Aulacorthum solani found on Brassicaceae and the Fabaceae specialist Acyrthosiphon pisum, was made to try to explain their respective feeding behaviour. Differences of GST were determined among ...

  14. Main Alkaloids of Peganum harmala L. and Their Different Effects on Dicot and Monocot Crops

    OpenAIRE

    Chi Zhang; Yuanming Zhang; Hua Shao; Xiaoli Huang

    2013-01-01

    Alkaloids with allelopathic activity are not as well-known as other allelochemicals. Our study revealed that total alkaloids from seeds of the medicinal plant Peganum harmala L. possessed significant growth inhibitory effect on four treated plants, with dicot plants (lettuce and amaranth) being more sensitive than the tested monocot plants (wheat and ryegrass). Further investigation led to the isolation of harmaline and harmine as the main active ingredients in the total alkaloids of P. harma...

  15. Allelopathic Potentialities of Gliricidia sepium and Acacia auriculiformis on the Germination and Seedling Vigour of Maize (Zea mays L.)

    OpenAIRE

    M. B. Oyun

    2006-01-01

    Decline in crop yield in cropping and agroforestry system in recent years has been attributed to allelopathic effects. Plants may favourably or adversely affect other plants through allelochemicals, which may be released directly or indirectly from live or dead plants. The objective of this study was to examine and quantify the nature of interference of leaf leachates of Gliricidia sepium and Acacia auriculiformis on seed germination and seedling vigour of maize and to identify morphological ...

  16. Mathematical Modeling of Plant Allelopathic Hormesis Based on Ecological-Limiting-Factor Models

    OpenAIRE

    Liu, Yinghu; Chen, Xiaoqiu; Duan, Shunshan; Feng, Yuanjiao; An, Min

    2010-01-01

    Allelopathy arises from the release of chemicals by one plant species that affect other species in its vicinity, usually to their detriment. Allelopathic effects have been demonstrated to be limiting factors for species distributions and ecological processes in some natural or agricultural communities. Based on the biphasic hormetic responses of plants to allelochemicals, ecological-limiting-factor models were introduced into the An-Johnson-Lovett hormesis model to improve modelling the pheno...

  17. The allelopathic effects of Festuca paniculata depend on competition in subalpine grasslands

    OpenAIRE

    Viard-Crétat, F.; Baptist, F.; Secher-Fromell, H.; Gallet, C.

    2012-01-01

    Allelopathy is recognized as an important process in plant-plant interactions, but how it affects plant communities growing in competitive conditions has not been assessed. This article investigates whether the allelopathic effect of Festuca paniculata is modified by competition between target plants in subalpine grasslands. We hypothesized that plants growing in mixed stands will be more affected by allelochemicals than the same species in monoculture. At Lautaret pass (Northern French Alps)...

  18. Can allelopathically active submerged macrophytes stabilise clear-water states in shallow lakes?

    OpenAIRE

    Hilt, Sabine; Gross, Elisabeth

    2008-01-01

    Inhibition of phytoplankton by allelochemicals released by submerged macrophytes is supposed to be one of the mechanisms that contribute to the stabilisation of clear-water states in shallow lakes. The relevance of this process at ecosystem level, however, is debated because in situ evidence is difficult to achieve. Our literature review indicates that allelopathically active species such as Myriophyllum, Ceratophyllum, Elodea and Najas or certain charophytes are among the most frequent subme...

  19. The chemical cross talk between rice and barnyardgrass

    OpenAIRE

    Kato-Noguchi, Hisashi

    2011-01-01

    The chemical cross talk between rice and barnyardgrass which is one of the most noxious weeds in rice cultivation was investigated. Allelopathic activity of rice was increased by the presence of barnyardgrass seedlings or barnyardgrass root exudates. Rice allelochemical, momilactone B, concentration in rice seedlings and momilactone B secretion level from rice were also increased by the presence of barnyardgrass seedlings or barnyardgrass root exudates. As momilactone B possesses strong growt...

  20. Dose-Response—A Challenge for Allelopathy?

    OpenAIRE

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

    2005-01-01

    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 no...

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

    OpenAIRE

    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 ...

  2. 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

  3. Seaweed allelopathy degrades the resilience and function of coral reefs

    OpenAIRE

    Rasher, Douglas B; Hay, Mark E.

    2010-01-01

    Coral reefs are in dramatic global decline due to a host of local- and global-scale anthropogenic disturbances that suppress corals and enhance seaweeds. This decline is exacerbated, and recovery made less likely, due to over-fishing of herbivores that normally limit seaweed effects on corals. Seaweeds were known to suppress coral reproduction and recruitment, but in a recent study, we demonstrated that numerous seaweeds also directly poison corals via lipid-soluble allelochemicals transferre...

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

    Science.gov (United States)

    Knuston, Sean; Slattery, Marc; Ankisetty, Sridevi; Goldstone, Jared V.; Watanabe, Kayo; Hoh, Eunha; Gadepalli, Rama S.; Rimoldi, John M.; Ostrander, Gary K.

    2016-01-01

    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. PMID:27136924

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

    OpenAIRE

    Asya P. Dragoeva; Zheni D. Nanova; Kalcheva, Vanya P.

    2010-01-01

    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 d...

  6. Ecología química y perspectivas de su aplicación en la conservación de la biodiversidad

    OpenAIRE

    Cortez, Vieyle

    2013-01-01

    Chemical ecology comprises the study of interactions of organisms with their environment that are mediated by the chemicals they produced. In general, chemicals that mediate interactions between organisms are called semiochemicals. Semiochemicals are divided into two major groups depending on whether the interactions are intraspecific (pheromones) or interspecific (allelochemics). The development of chemical ecology has been stimulated by the interest in knowing the details of the chemical in...

  7. Allelopathic Stress Produced by Bitter Gourd (Momordica charantia L.)

    OpenAIRE

    N.B. Singh; Sunaina

    2014-01-01

    The present study deals with in vitro effects of allelochemicals present in leaf and fruit leachate of Momordica charantia in vitro on plant growth and metabolism of Lycopersicon esculentum. Momordica was selected as a donor plant and tomato as recipient. Seeds of tomato were shown in pots and after germination different concentrations viz. 25, 50, 75 and 100% of leaf and fruit leachates were applied as treatment. Twenty days old seedlings were harvested for biophysical and biochemical analys...

  8. Significance of investigating allelopathic interactions of marine organisms in the discovery and development of cytotoxic compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, A.; Thakur, N.L.

    and Colombia reefs, aggressive sponge species Desmapsamma anchorata and Niphates erecta were abundant in regions with high diversity of other competitors such as regions with more than 25% coral cover [78]. The rapid growth rate and efficient regeneration... interactions; Allelochemicals; Cytotoxic compounds. 2 1. Introduction Living space is one of the basic requirements of any organism. In regions such as coral reefs and rocky intertidal areas, diverse sessile marine organisms share a limited space...

  9. 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.

  10. 植物间化感作用机理研究进展%Advances in Research on the Allelopathic of Plants

    Institute of Scientific and Technical Information of China (English)

    成钢; 张丹; 王伟亮; 朱伟玲; 琚淑明

    2015-01-01

    为了系统认识化感物质对植物作用的机理,从植物生长发育、生理生化代谢、基因表达3个方面对国内外植物化感作用的研究成果进行了综述。%Allelopathy can be widely found in the species.It is the main way of plants affect other plants and themselves.Also it is the important research direction to study the relationship between species.It help us learn more about the composition of the commu-nity and the process of succession.As the media of allelopathy ,allelochemical can play a role in itself and other plants.In order to understand the system of plant allelochemicals on the mechanism of action of plant rational allocation ,the correct choice of mixed species to create a healthy plant community systems provide a theoretical basis ,this article from allelochemicals on plant mineral ele-ment absorption , morphology ,physiology and biochemistry ,gene expression four on domestic and international aspects of plant allel-opathy studies were reviewed.

  11. Research Progress on Watermelon Allelopathy%西瓜化感作用研究进展

    Institute of Scientific and Technical Information of China (English)

    张小红; 赵依杰

    2013-01-01

    西瓜连作引起化感物质积累,导致产量下降,研究西瓜化感作用对揭示西瓜连作障碍机理、克服西瓜连作障碍具有重要的意义。本文对西瓜化感作用的研究进展进行了综述,包括西瓜化感现象的研究现状、化感物质及其释放途径、化感物质的作用特点、以及化感作用在西瓜生产实践中的应用,并提出西瓜化感作用未来的研究方向,旨在为制定增强西瓜抗逆性能和提高西瓜产量、品质的科学途径提供一定理论参考。%The continuous cropping of watermelon〔Citrullus lanatus(Thunb.)Matsum. et Nakai〕leads to the accumulation of allelochemicals,and causes the decrease of yield.It is of important significance to reveal the obstacle mechanism of allelopathic on watermelon continuous cropping,and overcome this obstacle.The paper reviewed the research progress on watermelon alle-lopathy,including the current research status on watermelon allelopathy,the allelochemicals and their releasing way,and the function characteristics of allelochemicals,and allelopathy application in pro-duction.The paper also prospected the future research directions on watermelon allelopathy,aiming at providing theoratical references for developing a scientific way to enhance watermelon resistance,and improving the yield and quality of watermelon.

  12. 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

  13. Gut microbes may facilitate insect herbivory of chemically defended plants.

    Science.gov (United States)

    Hammer, Tobin J; Bowers, M Deane

    2015-09-01

    The majority of insect species consume plants, many of which produce chemical toxins that defend their tissues from attack. How then are herbivorous insects able to develop on a potentially poisonous diet? While numerous studies have focused on the biochemical counter-adaptations to plant toxins rooted in the insect genome, a separate body of research has recently emphasized the role of microbial symbionts, particularly those inhabiting the gut, in plant-insect interactions. Here we outline the "gut microbial facilitation hypothesis," which proposes that variation among herbivores in their ability to consume chemically defended plants can be due, in part, to variation in their associated microbial communities. More specifically, different microbes may be differentially able to detoxify compounds toxic to the insect, or be differentially resistant to the potential antimicrobial effects of some compounds. Studies directly addressing this hypothesis are relatively few, but microbe-plant allelochemical interactions have been frequently documented from non-insect systems-such as soil and the human gut-and thus illustrate their potential importance for insect herbivory. We discuss the implications of this hypothesis for insect diversification and coevolution with plants; for example, evolutionary transitions to host plant groups with novel allelochemicals could be initiated by heritable changes to the insect microbiome. Furthermore, the ecological implications extend beyond the plant and insect herbivore to higher trophic levels. Although the hidden nature of microbes and plant allelochemicals make their interactions difficult to detect, recent molecular and experimental techniques should enable research on this neglected, but likely important, aspect of insect-plant biology. PMID:25936531

  14. Research advances in allelopathy of Quercus L.

    Institute of Scientific and Technical Information of China (English)

    Li Guang-de; Jia Li-ming; Li Xiao-wen

    2007-01-01

    The term allelopathy refers to biochemical interaction between all types of plants including microorganisms through production of chemical compounds that escape into the environment and exist widely in Quercus L. The development of investigations into types of allelochemicals,their compounding and spreading pathways,as well as expression of allelopathy in Quercus L. are reviewed in this paper:We have closely and systematically emphasized the functional mechanisms of allelopathy in forest plants for our next research project on allelopathy in Quercus L.

  15. 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.

  16. Cyanamide mode of action during inhibition of onion (Allium cepa L.) root growth involves disturbances in cell division and cytoskeleton formation

    OpenAIRE

    Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Gniazdowska, Agnieszka; Sliwinska, Elwira; Bogatek, Renata

    2011-01-01

    Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2–10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the enviro...

  17. Inhibition of tomato (Solanum lycopersicum L.) root growth by cyanamide is due to altered cell division, phytohormone balance and expansin gene expression

    OpenAIRE

    Soltys, Dorota; Rudzińska-Langwald, Anna; Gniazdowska, Agnieszka; Wiśniewska, Anita; Bogatek, Renata

    2012-01-01

    Cyanamide (CA) has been reported as a natural compound produced by hairy vetch (Vicia villosa Roth.) and it was shown also to be an allelochemical, responsible for strong allelopathic potential in this species. CA phytotoxicity has been demonstrated on various plant species, but to date little is known about its mode of action at cellular level. Treatment of tomato (Solanum lycopersicum L.) roots with CA (1.2 mM) resulted in inhibition of growth accompanied by alterations in cell division, an...

  18. Ecological Effects of Allelopathic Plants

    DEFF Research Database (Denmark)

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

    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. The...... 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...

  19. On the causality of the predisposition of conifers to the attack by needle eating insects with reference to Picea abies L. (Karst. ) and Gilpinia hercyniae Htg. (Hym. , Diprionidae). Zur Kausalanalyse der Disposition von Nadelbaeumen fuer den Befall durch nadelfressende Insekten am Beispiel Picea abies (L. ) Karst. und Gilpinia hercyniae Htg. (Hym. , Diprionidae)

    Energy Technology Data Exchange (ETDEWEB)

    Schopf, R.

    1986-01-01

    On the basis of biochemical needle analysis the predisposition of Norway spruce (Picea abies L. (Karst.)) to the attack by a needle eating insect (Gilpinia hercyniae Htg.; Hym., Diprionidae) is quantified. The physiological bond between the sawfly and spruce is divided in three different experimental levels: Synthesis of insect biomass by plant born nutrients; Physiological potency of the plant to inhibit the insect metabolism by allelochemicals; Physiological potency of the insect to break the plant defense. The importance of the predisposition of trees on the stability of forest ecosystems is discussed.

  20. Short-term effects of coumarin along the maize primary root axis

    OpenAIRE

    Lupini, Antonio; Sorgonà, Agostino; Miller, Anthony J.; Abenavoli, Maria Rosa

    2010-01-01

    The short-term effects of coumarin on three different maize primary root zones, transition zone (TZ, 3 mm) and two non-growing zones (NGZ1 and NGZ2 at 20 and 50 mm, respectively), were studied in order to investigate the effect of the allelochemical on maize root elongation rate (RER). The RER, plasma membrane (pm) H+-ATPase activity, quantitative pH changes and cell membrane potentials were evaluated. The results showed that coumarin caused at the TZ (1) an increased RER; (2) an enhancement ...

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

    OpenAIRE

    Kavita Yadav; Singh, N.B.

    2013-01-01

    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 ob...

  2. Brassinosteroids interact negatively with jasmonates in the formation of anti-herbivory traits in tomato.

    Science.gov (United States)

    Campos, Marcelo Lattarulo; de Almeida, Marcílio; Rossi, Mônica Lanzoni; Martinelli, Adriana Pinheiro; Litholdo Junior, Celso Gaspar; Figueira, Antonio; Rampelotti-Ferreira, Fátima Teresinha; Vendramim, José Djair; Benedito, Vagner Augusto; Peres, Lázaro Eustáquio Pereira

    2009-01-01

    Given the susceptibility of tomato plants to pests, the aim of the present study was to understand how hormones are involved in the formation of tomato natural defences against insect herbivory. Tomato hormone mutants, previously introgressed into the same genetic background of reference, were screened for alterations in trichome densities and allelochemical content. Ethylene, gibberellin, and auxin mutants indirectly showed alteration in trichome density, through effects on epidermal cell area. However, brassinosteroids (BRs) and jasmonates (JAs) directly affected trichome density and allelochemical content, and in an opposite fashion. The BR-deficient mutant dpy showed enhanced pubescence, zingiberene biosynthesis, and proteinase inhibitor expression; the opposite was observed for the JA-insensitive jai1-1 mutant. The dpy x jai1-1 double mutant showed that jai1-1 is epistatic to dpy, indicating that BR acts upstream of the JA signalling pathway. Herbivory tests with the poliphagous insect Spodoptera frugiperda and the tomato pest Tuta absoluta clearly confirmed the importance of the JA-BR interaction in defence against herbivory. The study underscores the importance of hormonal interactions on relevant agricultural traits and raises a novel biological mechanism in tomato that may differ from the BR and JA interaction already suggested for Arabidopsis. PMID:19734261

  3. 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.

  4. 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.

  5. 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.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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.

  9. Humic substances can modulate the allelopathic potential of caffeic, ferulic, and salicylic acids for seedlings of lettuce (Lactuca sativa L.) and tomato (Lycopersicon esculentum Mill.).

    Science.gov (United States)

    Loffredo, Elisabetta; Monaci, Linda; Senesi, Nicola

    2005-11-30

    The capacity of a leonardite humic acid (LHA), a soil humic acid (SHA), and a soil fulvic acid (SFA) in modulating the allelopathic potential of caffeic acid (CA), ferulic acid (FA), and salicylic acid (SA) on seedlings of lettuce (Lactuca sativa L.) and tomato (Lycopersicon esculentum Mill.) was investigated. Lettuce showed a sensitivity greater than that of tomato to CA, FA, and SA phytotoxicity, which was significantly reduced or even suppressed in the presence of SHA or SFA, especially at the highest dose, but not LHA. In general, SFA was slightly more active than SHA, and the efficiency of the action depended on their concentration, the plant species and the organ examined, and the allelochemical. The daily measured residual concentration of CA and FA decreased drastically and that of SA slightly in the presence of germinating seeds of lettuce, which were thus able to absorb and/or enhance the degradation of CA and FA. The adsorption capacity of SHA for the three allelochemicals was small and decreased in the order FA > CA > SA, thus suggesting that adsorption could be a relevant mechanism, but not the only one, involved in the "antiallelopathic" action. PMID:16302757

  10. Short-term effects of coumarin along the maize primary root axis.

    Science.gov (United States)

    Lupini, Antonio; Sorgonà, Agostino; Miller, Anthony J; Abenavoli, Maria Rosa

    2010-11-01

    The short-term effects of coumarin on three different maize primary root zones, transition zone (TZ, 3 mm), and two non-growing zones (NGZ1 and NGZ2 at 20 and 50 mm, respectively), were studied in order to investigate the effect of the allelochemical on maize root elongation rate (RER). The RER, plasma membrane (pm) H (+) -ATPase activity, quantitative pH changes and cell membrane potentials were evaluated. The results showed that coumarin caused at the TZ 1) an increased RER; 2) an enhancement of pm H (+) -ATPase activity and proton extrusion; and 3) a transient depolarization followed by a hyperpolarization of cell membrane potential. These observations were not evident in the NGZ1 and NGZ2 of the maize root. Coumarin-treatment in the NGZ1 did not change RER, but caused a membrane depolarization, while the NGZ2 was mostly insensitive to the allelochemical. These data suggested that the primary maize root was sensitive to coumarin within a 20 mm section from the root tip, but the more distal NGZ2 was not involved in coumarin-elicited physiological responses. PMID:21045563

  11. 烟草根系分泌物的GC-MS检测%Determination of tobacco root exudates by GC-MS

    Institute of Scientific and Technical Information of China (English)

    于会泳; 申国明; 高欣欣

    2013-01-01

    采用水培试验研究对连作障碍有重大影响的烟草根系分泌物中的化感物质,利用GC-MS检测出了K326和NC89两个烤烟品种移栽后40天根系分泌物中的酸溶性、碱溶性和中溶性组分种类,结果表明,两个烤烟品种共有的根系分泌物中可能是化感物质的种类包括有机酸类、酰胺类、酯类以及甘油和烟碱。%Hydroponic experiments were conducted to study allelochemicals released by tobacco root exudation. Acidic, neutral and alkaline soluble root exudates were extracted, separated and identified 40 days after K326 and NC89 plants were transplanted. Results showed that allelochemicals from root exudates of both cultivars were organic acids, lactam, esters, glycerol and nicotine.

  12. Cinnamic acid increases lignin production and inhibits soybean root growth.

    Directory of Open Access Journals (Sweden)

    Victor Hugo Salvador

    Full Text Available Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA oxidase and cinnamate 4-hydroxylase (C4H activities and lignin monomer composition in soybean (Glycine max roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H, guaiacyl (G, and syringyl (S lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth.

  13. Garlic Mustard (Alliaria petiolata) Glucosinolate Content Varies Across a Natural Light Gradient.

    Science.gov (United States)

    Smith, Lauren M

    2015-05-01

    Garlic mustard is a well-known invader of deciduous forests of North America, yet the influence of environmental factors on garlic mustard allelochemical production is not well understood. Three experiments were conducted to detect interactions between one garlic mustard allelochemical (glucosinolate) production and light availability. First, to detect patterns of glucosinolate production across a natural light gradient, leaves and roots of mature plants and first-year rosettes were sampled in patches ranging from 100 to 2 % of full sun within an Indiana forest. Second, to determine whether genetic variation drives observed correlations between glucosinolate content and light, seed collected across light gradients within six sites was grown in a common garden and glucosinolate production was measured. Finally, to understand whether local adaptation occurred in garlic mustard's response to light, seed collected from defined light environments across six sites was grown under four light treatments. Results of the field sampling showed that mature plants' root glucosinolate content was elevated in high compared to low light. In the common garden experiment, however, there was no correlation between light availability at seed origin and constitutive glucosinolate content. Additionally, in the common light treatments, there was no evidence for local adaptation to light environment. Overall, the results indicate that plasticity in response to light, not genetic variation among plants growing in different light environments, generates correlations between glucosinolate content and light in the field. Since mature garlic mustard populations in high light may exhibit increased glucosinolate content, it makes them potential targets for management. PMID:25912227

  14. 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. PMID:26625350

  15. Review of Studies on Allelopathy in Plants%植物化感作用研究动态

    Institute of Scientific and Technical Information of China (English)

    王春晴; 刘强; 李蕾

    2011-01-01

    In recent years, studies on allelopathy in plants were very active both at home and abroad. But most of the studies lack the in-depth study of the allelopathy mechanism. Hie species, release ways, influencing factors, function mechanism and mitigation methods of allel-ochemicals were reviewed based on the domestic and international researches.%近年来,国内外对植物化感作用的研究十分活跃.但是很多研究缺乏对化感作用机制的深入研究.结合国内外研究的现况,就化感物质的种类、作用途径、影响化感物质产生和释放的因素、化感物质的作用机理以及化感作用的缓解办法进行了综述.

  16. 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

  17. Allelopathy and Its Applications in Weed Control%化感作用及其在杂草防除中的应用

    Institute of Scientific and Technical Information of China (English)

    石旭旭; 王红春; 高婷; 娄远来

    2013-01-01

    Allelopathy is widely present in the plant kingdom and has great potential for weed control.We mainly discussed the determination of allelopathy,the release pathways of allelochemicals,the mechanism of action of allelopathic compounds,and the application and potential of allelopathy for weed control.%化感作用在植物界中广泛存在,在杂草防除方面潜力巨大.重点对化感作用的判定、化感物质的释放途径、化感作用的作用机制及其在杂草防除中的应用进行了讨论,并对化感作用在杂草防除中的应用方式和应用潜力进行了探讨.

  18. Analysis on Dynamic Heterosis for Allelopathy in Rice Under Different Environment Conditions

    Institute of Scientific and Technical Information of China (English)

    LIN Wen-xiong; DONG Zhang-hang; CHEN Xiang-xu; HE Hua-qin; SHEN Li-hua; GUO Yu-chun; LIANG Yi-yuan; CHEN Fang-yu; LIANG Kang-jing

    2003-01-01

    In this study, 5 parental rice varieties with different allelopathic potentials were employed indiallel cross [P(P+ 1)/2] to get a set of genetic materials including parental lines and two generations of F1 s.The dynamic heterosis for allelopathy in rice under different environmental conditions, was analyzed by usingadditive-dominant developmental genetic model. The results indicated that heterosis in both F1 and F2 showedinhibitory effects on shoot and root length of receiver plant (Lactuca sativa L. ). Heterosis over mid-parentbased on population mean(HMP) in F2 was lower than that in differental environmental conditions, showing1/2 HMP in F1. The heterosis in rice allelopathy was much higher under the field environmental conditionswith lower temperature and weaker sunlight than that under favorable environment, implying that the allel-opthic potential could be increased by stress environment. This finding interpreted the genetic reason thatplant could produce more allelochemicals under unfavorable environment.

  19. Allelopathy and Its Ecological Significance%植物化感作用及其生态学意义

    Institute of Scientific and Technical Information of China (English)

    席蓉; 郝建锋

    2011-01-01

    The paper introduces the concept of plant allelopathy,reviews the varieties, release path, mechanism and influencing factors of allelochemicals, summarizes the application of allelopathy in agriculture and forestry ecosystem, and at last predicts the development prospect of allelopathy.%介绍了植物化感作用的概念,综述了化感物质的种类和释放途径,分析了化感物质的作用机理及影响化感物质作用的因素,总结了植物化感作用在农林业、森林生态系统中的应用,并对化感作用的发展前景进行了展望.

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

    Science.gov (United States)

    Wang, Renjun; Wang, You; Tang, Xuexi

    2012-09-01

    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 Heterosigma akashiwo (Hada) Hada, Skeletonema costatum (Grev.) Grev, 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.

  1. Allelopathic potential of digera muricata, a desert summer annual

    International Nuclear Information System (INIS)

    Allelopathic potential of Digera muricata was tested on different crops by germinating them in different concentrations of D. muricata extract. It was observed that germination of all test species were highly affected in the higher concentration of D. muricata extract. Bulrush-millet was the most affected species. Decaying plant material of D. muricata was also found to be highly phytotoxic. Maximum reduction in growth of bulrush-millet was observed in the decaying root material. Phenolic compounds (Quercetin, sinapic and ferluic acid), alkaloids (cystine and berbine) and a terpenoid (limonene) were detected from roots and shoots of D. muricata, Greater quantities of all these allelochemicals were present in the roots followed by shoots. (author)

  2. Inhibition of tomato (Solanum lycopersicum L.) root growth by cyanamide is due to altered cell division, phytohormone balance and expansin gene expression.

    Science.gov (United States)

    Soltys, Dorota; Rudzińska-Langwald, Anna; Gniazdowska, Agnieszka; Wiśniewska, Anita; Bogatek, Renata

    2012-11-01

    Cyanamide (CA) has been reported as a natural compound produced by hairy vetch (Vicia villosa Roth.) and it was shown also to be an allelochemical, responsible for strong allelopathic potential in this species. CA phytotoxicity has been demonstrated on various plant species, but to date little is known about its mode of action at cellular level. Treatment of tomato (Solanum lycopersicum L.) roots with CA (1.2 mM) resulted in inhibition of growth accompanied by alterations in cell division, and imbalance of plant hormone (ethylene and auxin) homeostasis. Moreover, the phytotoxic effect of CA was also manifested by modifications in expansin gene expression, especially in expansins responsible for cell wall remodeling after the cytokinesis (LeEXPA9, LeEXPA18). Based on these results the phytotoxic activity of CA on growth of roots of tomato seedlings is likely due to alterations associated with cell division. PMID:22847024

  3. Cyanamide mode of action during inhibition of onion (Allium cepa L.) root growth involves disturbances in cell division and cytoskeleton formation.

    Science.gov (United States)

    Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Gniazdowska, Agnieszka; Sliwinska, Elwira; Bogatek, Renata

    2011-09-01

    Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2-10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the environment, but full recovery was observed only for tissue treated with this chemical at low concentration (2-6 mM). Cytological observations of root tip cells suggest that disturbances in cell division may explain the strong cyanamide allelopathic activity. Moreover, in cyanamide-treated onion the following changes were detected: reduction of mitotic cells, inhibition of proliferation of meristematic cells and cell cycle, and modifications of cytoskeleton arrangement. PMID:21573814

  4. 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.

  5. 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. PMID:25979966

  6. Current results on biological activities of lichen secondary metabolites: a review.

    Science.gov (United States)

    Molnár, Katalin; Farkas, Edit

    2010-01-01

    Lichens are symbiotic organisms of fungi and algae or cyanobacteria. Lichen-forming fungi synthesize a great variety of secondary metabolites, many of which are unique. Developments in analytical techniques and experimental methods have resulted in the identification of about 1050 lichen substances (including those found in cultures). In addition to their role in lichen chemotaxonomy and systematics, lichen secondary compounds have several possible biological roles, including photoprotection against intense radiation, as well as allelochemical, antiviral, antitumor, antibacterial, antiherbivore, and antioxidant action. These compounds are also important factors in metal homeostasis and pollution tolerance of lichen thalli. Although our knowledge of the contribution of these extracellular products to the success of the lichen symbiosis has increased significantly in the last decades, their biotic and abiotic roles have not been entirely explored. PMID:20469633

  7. 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.

  8. Role of drought in outbreaks of plant-eating insects. Drought's physiological effects on plant can predict it influence on insect populations

    Energy Technology Data Exchange (ETDEWEB)

    Mattson, W.J.; Haack, R.A.

    1987-02-01

    This paper presents a holistic conceptual model to explain how drought may provoke insect outbreaks. First, drought stress affects plant traits - gene expression and genomic change; plant growth and differentiation; spectral qualities, temperature, and acoustic emissions; osmolytes, minerals, nitrogen, and carbohydrates; allelochemicals and volatile stress metabolites. Second, drought, affects aspects of insect behavior and physiology: (1) drought provides a more favorable thermal environment for growth of phytophagous insects, (2) drought-stressed plants are behaviorally more attractive or acceptable for insects, (3) drought-stressed plants are physiologically more suitable for insects, (4) drought enhances insect detoxication systems and immunocompetence, and (5) drought favors mutualistic microorganisms but not natural enemies of phytophagous insects, and (6) drought may induce genetic changes in insects.

  9. 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. PMID:12590453

  10. Main Alkaloids of Peganum harmala L. and Their Different Effects on Dicot and Monocot Crops

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2013-02-01

    Full Text Available Alkaloids with allelopathic activity are not as well-known as other allelochemicals. Our study revealed that total alkaloids from seeds of the medicinal plant Peganum harmala L. possessed significant growth inhibitory effect on four treated plants, with dicot plants (lettuce and amaranth being more sensitive than the tested monocot plants (wheat and ryegrass. Further investigation led to the isolation of harmaline and harmine as the main active ingredients in the total alkaloids of P. harmala seeds. Harmaline exerted potent inhibitory effects on seedling growth of treated plants, especially dicots, inhibiting root elongation of lettuce and amaranth by 31% and 47% at a very low concentration (5 µg/mL, whereas harmine exhibited much weaker non-selective inhibitory effect on the plants. Considering the high yield and poor utilization of P. harmala in China, we anticipate that this plant could be exploited as an alternative weed management tool in the future.

  11. 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.

  12. 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.

  13. 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.

  14. Selection of processing tomato genotypes with high acyl sugar content that are resistant to the tomato pinworm.

    Science.gov (United States)

    Dias, D M; Resende, J T V; Faria, M V; Camargo, L K P; Chagas, R R; Lima, I P

    2013-01-01

    Acyl sugars are allelochemicals present at high concentrations in leaves of accessions of the wild tomato Solanum pennellii; they confer resistance to a large number of arthropod pests, including the tomato pinworm, Tuta absoluta (Lepidoptera, Gelechiidae). Accession 'LA716', with high contents of acyl sugars in the leaves, was used as a source of resistance to start a genetic breeding program of processing cultivated tomato, S. lycopersicum. We selected plants of the F₂ generation of an interspecific cross (S. lycopersicum cv. 'Redenção' x S. pennellii 'LA716') for extremes of concentrations (high and low) of acyl sugars in the leaves and evaluated the resistance of selected genotypes to the tomato pinworm, compared with plants of the parental and F₁ generations. The concentrations of acyl sugars present in the genotypes selected for high contents were close to those of S. pennellii 'LA 716', while the genotypes with low concentrations of acyl sugars were close to cultivar 'Redenção'. The F₁ hybrid ('Redenção' x 'LA716') had intermediate concentrations of acyl sugars, but was closer to Redenção, indicating that the inheritance of this type of character is due to a recessive major gene, along with minor genes with additive effects. There was a direct association between high contents of acyl sugars and non-preference for oviposition and suppression of larval development, indicating that the allelochemical acts through mechanisms of non-preference for oviposition and through antibiosis. Genotypes with high contents of acyl sugars were more effective in reducing the damage caused by the tomato pinworm. Genotypes RVTA-2010pl#94 and RVTA-2010pl#31, selected for high contents of acyl sugars, showed a good level of resistance to T. absoluta, similar to the wild genotype LA716. These genotypes are promising for use in a breeding program for developing commercial processing tomatoes. PMID:23420362

  15. 淡水生态系统中的他感作用研究进展%Development of Research of Allelopathy in Freshwater Ecosystem

    Institute of Scientific and Technical Information of China (English)

    金秋; 金则新; 奚立民

    2012-01-01

    综述了目前淡水生物间他感作用的相关报导,给出了他感作用来源生物、他感物质和他感作用结果.并对淡水生物所产生的他感物质的种类及其作用模式,包括抑制酶活性、抑制光合作用等以及影响淡水生物间他感作用的因子,包括营养盐、非营养因子和微生物作了叙述和分析.阐述了淡水生物间他感作用的应用前景和目前研究所存在的问题,并对本研究领域未来的发展提出了展望.%This article reviewed the relevant reports on allelopathy in freshwater organisms up to the present,and gave the donor organisms of allelopathy, allelochemicals and the results of allelopathy. The categories and active modes of al-lelochemicals including inhibition of activity of enzyme,inhibition of photosynthesis etc.,and factors which can influence the effectiveness of the allelopathy of freshwater organisms including nutrients, non-nutrient factors and microorganisms were specified and analyzed. The application perspectives of allelopathy in freshwater organisms and problems lied in the relevant research works were expatiated. The future development prospect of this research fields was brought forward.

  16. 林木种间的化感作用%Effects of Allelopathy Among Tree Species

    Institute of Scientific and Technical Information of China (English)

    林文欢; 詹潮安; 陈红跃

    2011-01-01

    Effects of allelopathy among plants are a common phenomenon in natural world.Allelopathic effects play important roles on crop cultivation,weed control,pest control and plantation building.Collocation of tree species is a key factor in mixed plantation building.Effects of allelopathy among tree species play a crucial role in selection of tree species.The paper reviewed the research advances on allelopathic effects among the common tree species in mixed plantation in terms of collection and extraction of allelochemicals,authentication of allelochemicals and expressions of allelopathic effects.The research on the allelopathic effects among the tree species was aimed at providing scientific basis for tree species composition of plantation and giving service support to non-commercial forest.%植物化感作用是自然界普遍存在的一种现象,在农作物耕作、杂草控制、病虫害防治以及林木营造等方面发挥着重要作用。树种搭配是成功营造人工混交林的关键,林木种间的化感作用在混交树种的选择上起着重要作用。文中从化感物质的收集与提取、化感物质的鉴定以及化感作用的表达等方面,对人工混交林常见树种间化感作用的研究情况和成果进行综述,以期为混交林选择树种组合提供科学依据,为生态公益林建设服务。

  17. Consumption and utilization of experimentally altered corn by southern armyworm: Iron, nitrogen, and cyclic hydroxamates.

    Science.gov (United States)

    Manuwoto, S; Scriber, J M

    1985-11-01

    The effects of differential leaf water, leaf nitrogen and cyclic hydroxamate (DIMBOA) concentrations in corn seedlings were analyzed for a polyphagous insect, the southern armyworm (Spodoptera eridania Cram.). Six different combinations of nutrients and allelochemicals [DIMBOA = 2,4-dihydroxy-7-methoxy(2H)-benzoxazin-3(4H)-one] were generated using two corn genotypes (WF9 and CI3IA) and three fertility regimes (complete nutrient, Fe-deficient, and N-deficient solutions) in the University Biotron. Poorest larval growth was observed in the low-nitrogen treatments (1.2% and 1.7% leaf N) and was the result of both low consumption rates and high metabolic costs (low efficiency of conversion of digested food, ECD). Fastest growth rates were observed forthe larvae fed leaves from the high-nitrogen treatments (4.6% and 4.4% leaf N). It is noteworthy that these treatments also contained the highest concentration of cyclic hydroxamates, which are generally believed to be the primary defensive chemicals mediating resistance against the European corn borer,Ostrinia nubilalis (Hubner). If these hydroxamates do have any deleterious or costly effects (perhaps accounting for a large portion of metabolic expenditures), the high digestibility of the leaf tissue and the increased consumption rates more than compensate, resulting in rapid growth (growth rate = consumption rate × approximate digestibility × efficiency of conversion of the digested food). These studies illustrate that variation in key nutrients and allelochemicals within a single plant species (Zea mays L.) may have significantly different effects upon various potential leaf-chewing caterpillars, such as these armyworms versus corn borers (which cannot handle the cyclic hydroxamates, even if provided with young nutritious leaf tissues). PMID:24311240

  18. 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 < C. album < P. oleracea ≤ A. retroflexus. The results were in agreement with recent findings of the suppression of these 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. PMID:22614450

  19. 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

  20. Germination tests for assessing biochar quality.

    Science.gov (United States)

    Rogovska, N; Laird, D; Cruse, R M; Trabue, S; Heaton, E

    2012-01-01

    Definition, analysis, and certification of biochar quality are crucial to the agronomic acceptance of biochar. While most biochars have a positive impact on plant growth, some may have adverse effects due to the presence of phytotoxic compounds. Conversely, some biochars may have the ability to adsorb and neutralize natural phytotoxic compounds found in soil. We evaluated the effects of biochars on seedling growth and absorption of allelochemicals present in corn ( L.) residues. Corn seeds were germinated in aqueous extracts of six biochars produced from varied feedstocks, thermochemical processes, and temperatures. Percent germination and shoot and radicle lengths were evaluated at the end of the germination period. Extracts from the six biochars had no effect on percent germination; however, extracts from three biochars produced at high conversion temperatures significantly inhibited shoot growth by an average of 16% relative to deionized (DI) water. Polycyclic aromatic hydrocarbons detected in the aqueous extracts are believed to be at least partly responsible for the reduction in seedling growth. Repeated leaching of biochars before extract preparation eliminated the negative effects on seedling growth. Biochars differ significantly in their capacity to adsorb allelochemicals present in corn residues. Germination of corn seeds in extracts of corn residue showed 94% suppression of radicle growth compared to those exposed to DI water; however, incubation of corn residue extracts with leached biochar for 24 h before initiating the germination test increased radicle length 6 to 12 times compared to the corn residue extract treatments. Germination tests appear to be a reliable procedure to differentiate between effects of different types of biochar on corn seedling growth. PMID:22751043

  1. 陆生植物化感作用的抑藻研究进展%Advance research on the allelopathy of terrestrial plants in inhibition of algae

    Institute of Scientific and Technical Information of China (English)

    倪利晓; 陈世金; 任高翔; 郝向阳

    2011-01-01

    Currently, it is a hot issue in environmental field to control algal bloom effectively and to treat the eutrophic water body. The allelochemical is the secondary metabolites what are produced by plants, bacteria, viruses and fungi. The allelopathy of aquatic autotrophs has drawn the most attention because it is believed to be high effective, low toxic and eco-friendly approach to control algal blooms. However, only a little research has been carried on the algicidal activity of the terrestrial plants. This paper made a systematic discussion on the evolution of the concept of the allelopathy, many kinds of biological inhibitions on algae and the mechanism of allelochemicals, ect. And it summarizes the research progress of the allelopathy of terrestrial plants in inhibition of algae by domestic and foreign scholars in recent years. The paper considered that the advantages of terrrstrial plants which were compared with aquatic ones embodied some aspects such as obvious allelopathy effect, rich allelopathy and noise immunity in aquatic biological environment, ect. And it also made a prospect for the research direction of the terrestrial plants in algal inhibition. The terrestrial plants and especially the compositae have a broad prospects in inhibition of algae. Finally, there are still some questions in several aspects such as a deep exploration and improvement of the allelopathy's extraction and identification, the research of the mechanism of allelochemicals, ecological safety and so on should be solved.%有效控制水华,治理富营养化水体是目前环境领域的研究热点和前沿.所谓化感物质,就是由植物、细菌、病毒和真菌所产生的二次代谢产物.利用水生植物的化感作用或化感物质抑制水体中藻类的爆发被认为是一种高效、低毒、环境亲合性好的方法而备受关注.然而,对于陆生植物应用于抑制藻类生长的研究却较少.文章在对化感作用的概念的演化、各种生物对

  2. Sementes como fonte alternativa de substâncias químicas com atividade alelopática Seeds as alternative source of chemical substances with allelopathic activity

    Directory of Open Access Journals (Sweden)

    A.P.S Souza Filho

    2011-09-01

    Full Text Available Na literatura mundial, observa-se predominância das folhas como meio preferencial de estudos de compostos químicos promissores, embora informações sobre outras frações da planta também sejam encontradas. Essa tendência se deve ao fato de que a maioria dos estudos mostra as folhas com atividade potencialmente alelopática de intensidade superior à das demais frações. Nesta revisão, procurou-se compilar e analisar as informações disponíveis sobre a importância das sementes como fonte alternativa de compostos químicos com atividade alelopática. São discutidas as variações na produção e na alocação de aleloquímicos em função do estádio ontogenético das sementes presentes no banco de sementes. É discutido também o papel dos aleloquímicos produzidos por sementes na repelência de insetos, na inibição do desenvolvimento de patógenos nas sementes, na inibição do desenvolvimento inicial de plantas daninhas e como sinalizador positivo para a simbiose com microrganismos do solo. Apresenta-se ainda a atividade alelopática de diversas substâncias isoladas de sementes, destacando-se os alcaloides, flavonoides, benzoxazinoides e resinas glicosídicas. Os estudos de aleloquímicos produzidos por sementes podem contribuir expressivamente para o melhor entendimento do papel ecológico que essas substâncias desempenham na ecologia química dos agro e ecossistemas.In the literature, leaves predominate as preferred source of studies of promising allelopathic compounds, but information on other plant fractions are also found. This trend is due to the fact that most studies show that leaves have higher allelopathic potential than other plant fractions. In this review, we compiled and analyzed the information available on the importance of seeds as an alternative source of chemical compounds with allelopathic activity. We discussed the variations in production and allocation of allelochemicals at different ontogenetic stages of

  3. Insecticide resistance mechanisms in the green peach aphid Myzus persicae (Hemiptera: Aphididae II: Costs and benefits.

    Directory of Open Access Journals (Sweden)

    Andrea X Silva

    Full Text Available BACKGROUND: Among herbivorous insects that have exploited agro-ecosystems, the peach-potato aphid, Myzus persicae, is recognized as one of the most important agricultural pests worldwide. Uses over 400 plant species and has evolved different insecticides resistance mechanisms. As M. persicae feeds upon a huge diversity of hosts, it has been exposed to a wide variety of plant allelochemicals, which probably have promoted a wide range of detoxification systems. METHODOLOGY/PRINCIPAL FINDINGS: In this work we (i evaluated whether insecticide resistance mutations (IRM in M. persicae can give an advantage in terms of reproductive fitness when aphids face two hosts, pepper (Capsicum annuum a suitable host and radish (Raphanus sativus the unfavorable host and (ii examined the transcriptional expression of six genes that are known to be up-regulated in response to insecticides. Our results show a significant interaction between host and IRM on the intrinsic rate of increase (r(m. Susceptible genotypes (not carrying insensitivity mutations had a higher r(m on pepper, and the transcriptional levels of five genes increased on radish. The r(m relationship was reversed on the unfavorable host; genotypes with multiple IRM exhibited higher r(m, without altering the transcriptional levels of the studied genes. Genotypes with one IRM kept a similar r(m on both hosts, but they increased the transcriptional levels of two genes. CONCLUSIONS/SIGNIFICANCE: Although we have studied only nine genotypes, overall our results are in agreement with the general idea that allelochemical detoxification systems could constitute a pre-adaptation for the development of insecticide resistance. Genotypes carrying IRM exhibited a higher r(m than susceptible genotypes on radish, the more unfavorable host. Susceptible genotypes should be able to tolerate the defended host by up-regulating some metabolic genes that are also responding to insecticides. Hence, our results suggest that

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

    Directory of Open Access Journals (Sweden)

    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

  5. 旋链角毛藻和中肋骨条藻间的他感作用%Allelopathic effects between Chaetoceros curvisetus and Skeletonema costatum

    Institute of Scientific and Technical Information of China (English)

    张议文; 王江涛

    2012-01-01

    选择两种常见硅藻——中肋骨条藻(Skeletonema costatum)和旋链角毛藻(Chaetoceros curvisetus)为研究对象,采用滤液培养的方法考察二者之间的他感效应,结果表明:f/2全营养培养条件下,旋链角毛藻指数后期无藻细胞滤液对中肋骨条藻的生长有显著抑制作用,抑制率随旋链角毛藻滤液比例的增大而增大,他感效应随作用时间消退后,中肋骨条藻生长速率提高,且随着旋链角毛藻滤液比例的增大,中肋骨条藻的细胞粒径有减小的趋势;中肋骨条藻指数后期无藻细胞滤液对旋链角毛藻的生长速率和细胞粒径均无影响,表明中肋骨条藻对旋链角毛藻无他感作用.本实验结果可为下一步提取他感物质、研究他感作用机理提供实验基础.%The two common types of diatom, respectively Chaetoceros curvisetus and Skeletonema costatum, were chosen to observe and study the allelopathic effect between them by means of cell-free filtrate culture. The observation showed that under the condition of enriched , cell-free filtrate of the C. curvisetus culture inhibited the growth of 5. costatum significantly in the later exponential growth phase. The inhibition rate was related to the proportion of C. curvisetus cell-free filtrate in the culture, in addition the diameter of S. costatum was affected as well. Allelochemical degraded as time went on, and then the relative growth rate of 5. costatum was increased. There was no influence on the relative growth rate and diameter of S. costatum by enriched C. cumsetus cell-free Citrate in the end of exponential growth phase, which showed that there was not allelopathic effect of S. costatum on C. curuisetus. The results provided the experimental basis for extracting allelochemical and researching allelopathic mechanism later.

  6. Allelopathic effect of Bromus spp. and Lolium spp. shoot extracts on some crops.

    Science.gov (United States)

    Lehoczky, E; Nelima, M Okumu; Szabó, R; Szalai, A; Nagy, P

    2011-01-01

    Allelopathy is an untapped resource for weed control in crops that could give good possibilities for environmentally sound, integrated crop production. Allelopathy is defined as the direct or indirect harmful or beneficial effects of one plant on another through the production of chemical compounds, called allelochemicals, which escape into the environment. Allelochemicals can be produced by weeds and affect crops, and the reverse is also true. Allelopathic interactions include weed-weed, weed-crop, and crop-crop. Allelopathy offers potential for selective biological weed control for instance weed-suppressing crops and the use of plant residues in cropping systems, allelopathic rotational crops, or companion plants with allelopathic potential. Bromus species occur in many habitats in temperate regions of the world, including America, Eurasia, Australia, and Africa. The genus Lolium is one of the most important forage grasses. The weed species usually grow in the same production zones as wheat and are considered weeds since they parasitize wheat fields. Some of the weed species in these two genus have been reported to have allelopathic effect. One of the methods that has been successful in studying allelopathic activity are bioassays. Laboratory experiments were conducted to determine allelopathic effect of watery shoot extracts of four weed species of the Poaceae family, namely Bromus rigidus, Bromus diandrus, Lolium multiflorum and Lolium temulentum on germination and growth of winter wheat (Triticum aestivum L.), spring barley (Hordeum vulgare L.), corn (Zea mays L), perennial ryegrass (Lolium perenne L.), bean (Phaseolus sp.) and sunflower (Helianthus annuus L.) and on each other. The experiment was carried out during the period March 2010 to October 2010. Twenty five seeds were put into one Petri-dish on filter paper, adding 15ml of extract to each in four repeats. The germination took place in a Binder-type thermostat in the dark. The timing of germination was

  7. Atividade alelopática da leucena sobre espécies de plantas daninhas Allelopathic activity of leucaena on weed species

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    Nádja de Moura Pires

    2001-03-01

    Full Text Available Alelopatia é o efeito direto ou indireto de uma planta sobre outra, por meio da produção de compostos químicos liberados no ambiente. Os metabólitos secundários ou produtos naturais envolvidos em alelopatia são denominados aleloquímicos e estão presentes nos tecidos de diferentes partes das plantas. O objetivo deste trabalho foi determinar o potencial alelopático da leucena (Leucaena leucocephala (Lam. de Wit. sobre as plantas daninhas Desmodium purpureum (desmódio, Bidens pilosa (picão-preto e Amaranthus hybridus (caruru. Os bioensaios foram conduzidos em laboratório e em casa de vegetação com extratos aquosos da parte aérea da leucena nas concentrações de 100, 50, 25, 12,5 % (v v-1. O extrato apresentou maior efeito quando aplicado em papel filtro. O potencial alelopático da leucena variou com a espécie de planta daninha, sendo o picão-preto e o caruru as espécies mais sensíveis ao extrato em ambos os bioensaios. A mimosina foi quantificada por HPLC em concentrações diretamente correlacionadas à concentração do extrato, indicando ser este aleloquímico o provável responsável pelo efeito sobre a germinação e o desenvolvimento das plantas daninhas.Allelopathy is the direct or indirect effect of one plant on another through substances liberated into the environment, and occurs widely in natural plant communities. The secondary metabolites or natural products involved in allelopathy are called allelochemicals and can be produced in different parts of the plants. The purpose of this study was to determine the allelopathic potential of the aerial part of Leucaena leucocephala on the weeds Desmodium purpureum, Bidens pilosa and Amaranthus hybridus. Bioassays were carried out in laboratory and in greenhouse with aqueous extracts of the aerial part of leucaena in concentrations of 100, 50, 25, 12.5 % (v v-1. The aqueous extract showed major effect over the weeds when applied to filter paper. The allelopathic potential of

  8. Hormesis in mixtures -- can it be predicted?

    Science.gov (United States)

    Belz, Regina G; Cedergreen, Nina; Sørensen, Helle

    2008-10-01

    Binary mixture studies are well established for mixtures of pollutants, pesticides, or allelochemicals and sound statistical methods are available to evaluate the results in relation to reference models. The majority of mixture studies are conducted to investigate the effect of one compound on the inhibitory action of another. However, since stimulatory responses to low concentrations of chemicals are gaining increased attention and improved statistical models are available to describe this phenomenon of hormesis, scientists are challenged by the question of what will happen in the low concentration range when all or some of the chemicals in a mixture induce hormesis? Can the mixture effects still be predicted and can the size and concentration range of hormesis be predicted? The present study focused on binary mixtures with one or both compounds inducing hormesis and evaluated six data sets of root length of Lactuca sativa L. and areal growth of Lemna minor L., where substantial and reproducible hormetic responses to allelochemicals and herbicides have been found. Results showed that the concentration giving maximal growth stimulatory effects (M) and the concentration where the hormetic effect had vanished (LDS) could be predicted by the most-used reference model of concentration addition (CA), if the growth inhibitory concentrations (EC50) followed CA. In cases of deviations from CA at EC50, the maximum concentration M and the LDS concentration followed the same deviation patterns, which were described by curved isobole models. Thus, low concentration mixture effects as well as the concentration range of hormesis can be predicted applying available statistical models, if both mixture partners induce hormesis. Using monotonic concentration-response models instead of biphasic concentration-response models for the prediction of joint effects, thus ignoring hormesis, slightly overestimated the deviation from CA at EC20 and EC50, but did not alter the general

  9. Fall armyworm sensitivity to flavone: Limited role of constitutive and induced detoxifying enzyme activity.

    Science.gov (United States)

    Wheeler, G S; Slansky, F; Yu, S J

    1993-04-01

    We used inhibition and induction of detoxifying enzymes to determine whether these enzymes allow a generalist species (Spodoptera frugiperda; fall armyworms) to cope with ingestion of the flavonoid, flavone. Flavone induces polysubstrate monooxygenases (PSMO), general esterases (GE), and glutathioneS-transferases (GST) inS. frugiperda, yet this species is affected deleteriously by low dietary concentrations of this allelochemical. First, in a series of experiments, larvae were fed artificial diets containing increasing concentrations of flavone, either alone or with known inhibitors of either PSMO, GE, or GST enzymes. In an additional treatment, flavone and inhibitors of all three enzyme systems were administered in diets simultaneously. PSMO and GE activities were reduced in vivo by their respective inhibitors, whereas that of GST was induced or unchanged. Significant synergism of flavone's growth-reducing activity occurred at the highest concentration tested (0.125% fresh mass, fm) when the PSMO inhibitor, piperonyl butoxide, or the GST inhibitor, diethyl maleate, was added to the diet, and at 0.08% fm flavone, when combined with the GE inhibitor, tri-tolyl phosphate. In many cases, however, the additive effect (i.e., reduction in growth owing to flavone alone + inhibitor alone) was greater than the synergistic effect, and no synergism occurred in the treatment with the three inhibitors combined. In the second approach, caterpillars were preexposed to a concentration of flavone (0.02% fm) that induced these enzymes ca. 1.5- to 2.5-fold, prior to switching larvae to a diet containing a higher (growth-reducing) flavone concentration (0.125% fm). The relative growth rates (RGR) of induced larvae were significantly greater (14%) than those of the uninduced larvae on the 0.125% fm flavone diet. Additionally, in two of the three experiments, relative consumption rate (RCR) was significantly greater (7-24%) in induced compared with uninduced larvae. The variable

  10. Development of Novel Drugs from Marine Surface Associated Microorganisms

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    Suhelen Egan

    2010-03-01

    Full Text Available While the oceans cover more than 70% of the Earth’s surface, marine derived microbial natural products have been largely unexplored. The marine environment is a habitat for many unique microorganisms, which produce biologically active compounds (“bioactives” to adapt to particular environmental conditions. For example, marine surface associated microorganisms have proven to be a rich source for novel bioactives because of the necessity to evolve allelochemicals capable of protecting the producer from the fierce competition that exists between microorganisms on the surfaces of marine eukaryotes. Chemically driven interactions are also important for the establishment of cross-relationships between microbes and their eukaryotic hosts, in which organisms producing antimicrobial compounds (“antimicrobials”, may protect the host surface against over colonisation in return for a nutrient rich environment. As is the case for bioactive discovery in general, progress in the detection and characterization of marine microbial bioactives has been limited by a number of obstacles, such as unsuitable culture conditions, laborious purification processes, and a lack of de-replication. However many of these limitations are now being overcome due to improved microbial cultivation techniques, microbial (meta- genomic analysis and novel sensitive analytical tools for structural elucidation. Here we discuss how these technical advances, together with a better understanding of microbial and chemical ecology, will inevitably translate into an increase in the discovery and development of novel drugs from marine microbial sources in the future.

  11. Some soybean cultivars have ability to induce germination of sunflower broomrape.

    Science.gov (United States)

    Zhang, Wei; Ma, Yongqing; Wang, Zhong; Ye, Xiaoxin; Shui, Junfeng

    2013-01-01

    Sunflower broomrape is a noxious parasitic weed which has caused severe damage to crop ecosystems. Trap crops can release a mixture of allelochemicals to induce the germination of sunflower broomrape. We studied the allelopathic effects of soybean on sunflower broomrape. Fourteen common soybean cultivars were grown in pots. Samples were collected from soybean plants and rhizosphere soil at five growth stages (V1, V3, V5, R2, and R4). The allelopathic effects of soybean reached highest at the V3 stage. Methanolic extracts of soybean roots induced higher broomrape germination than methanolic extracts of stems or leaves. The germination rates induced by root extracts (10-fold dilution) were positively correlated with germination rates induced by stem (10-fold dilution) and leaf extracts (10-fold dilution). The broomrape germination rates induced by root extracts were also positively correlated with soybean nodule diameter and dry weight. The results indicated that soybeans could induce sunflower broomrape germination. We conclude that soybean has the potential to be used as a trap crop for sunflower broomrape. PMID:23544089

  12. Some soybean cultivars have ability to induce germination of sunflower broomrape.

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    Full Text Available Sunflower broomrape is a noxious parasitic weed which has caused severe damage to crop ecosystems. Trap crops can release a mixture of allelochemicals to induce the germination of sunflower broomrape. We studied the allelopathic effects of soybean on sunflower broomrape. Fourteen common soybean cultivars were grown in pots. Samples were collected from soybean plants and rhizosphere soil at five growth stages (V1, V3, V5, R2, and R4. The allelopathic effects of soybean reached highest at the V3 stage. Methanolic extracts of soybean roots induced higher broomrape germination than methanolic extracts of stems or leaves. The germination rates induced by root extracts (10-fold dilution were positively correlated with germination rates induced by stem (10-fold dilution and leaf extracts (10-fold dilution. The broomrape germination rates induced by root extracts were also positively correlated with soybean nodule diameter and dry weight. The results indicated that soybeans could induce sunflower broomrape germination. We conclude that soybean has the potential to be used as a trap crop for sunflower broomrape.

  13. Studies on the antibacterial and nucleic acid degradation property of Cassia alata

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    Elangomathavan Ramaraj

    2014-03-01

    Full Text Available This study aimed to screen preliminary phytochemical profile of the leaf extract of Cassia alata (L,one of the ethnomedicinal plants used by the Kani tribes of the Western Ghats, Tamilnadu, India. To evaluate the antimicrobial potential of multiple solvent based crude leaf extracts of the selected plant species C. alataagainst the few target human pathogenic microorganisms.Multiple solvents were used for the extraction of allelochemicals from thedried leaf material. Crudeextracts were subjected to evaluate their efficacy in controlling the target microorganism’s growth at in vitrolevel. Variation in the total nucleic acid content was also assessed in both control and treated bacterial samples. C. alata leaf extract chemical profile revealed the presence of secondary metabolites like tannins, phlobatanins, saponins, flavonoids, steroids, terpenoids and alkaloids. Crude extracts prepared in the Soxhlet apparatus ceased the growth of Salmonella typhi andPseudomonas aeruginosa. Proteus vulgaris andKlebsiella pneumoniaewere resistant even while fortified with 3 mg/ml extract concentration. Extract treated bacteria lack the total nucleic acid content, which proves and supports the presence of antimicrobial potential. Multiple solvent based C. alata leaf crude extracts have the potential to control one ofthe most important human pathogens S. typhi. This plant could be exploited further for the analysis of active principles towards the optimization of drug, as an evidence for sustainable utilization of the traditional knowledge on medicinal plants used by the Kani tribes herbal healers.

  14. Allelopathic Stress Produced by Bitter Gourd (Momordica charantia L.

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    N.B. Singh

    2014-05-01

    Full Text Available The present study deals with in vitro effects of allelochemicals present in leaf and fruit leachate of Momordica charantia in vitro on plant growth and metabolism of Lycopersicon esculentum. Momordica was selected as a donor plant and tomato as recipient. Seeds of tomato were shown in pots and after germination different concentrations viz. 25, 50, 75 and 100% of leaf and fruit leachates were applied as treatment. Twenty days old seedlings were harvested for biophysical and biochemical analyses. The root and shoot length, fresh and dry weight of the seedlings decreased in dose dependent manner. The reduction in pigment and protein contents and nitrate reductase activity was concentration dependent. Membrane leakage increased as the concentration of leachates increased. Activities of antioxidant enzymes viz. superoxide dismutase (SOD, catalase (CAT and peroxidase (POX activities significantly enhanced under allelopathic stress. Inhibition of various metabolic activities under allelopathic stress resulted in decreased plant growth and development. The fruit leachate of Momordica was more inhibitory than leaf leachate.

  15. Changes in soft coral Sarcophyton sp. abundance and cytotoxicity at volcanic CO2 seeps in Indonesia

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    Hedi Indra Januar

    2016-04-01

    Full Text Available This study presents the relationship between benthic cover of Sarcophyton sp. living on coral reefs and their cytotoxicity (an assumption of soft coral allelochemical levels along acidification gradients caused by shallow water volcanic vent systems. Stations with moderate acidification (pH 7.87 ± 0.04, low acidification (pH 8.01 ± 0.04, and reference conditions (pH 8.2 ± 0.02 were selected near an Indonesian CO2 seep (Minahasa, Gunung Api Island, and Mahengetang Island. Cover of the dominant soft coral species (Sarcophyton sp. was assessed and tissue samples were collected at each site. The cytotoxicity tissue extracts were analyzed using the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolinon bromide (MTT method. Levels of cytotoxicity were strongly correlated with Sarcophyton sp. cover (p < 0.05; R2 = 0.60 at 30 ppm and 0.56 at 100 ppm, being highest at mean pH 8.01 where the soft corals were most abundant. This finding suggests that Sarcophyton sp. can be expected to survive ocean acidification near Indonesia in the coming decades. How the species might be adversely affected by further ocean acidification later in the century unless CO2 emissions are reduced remains a concern.

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

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    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.

  17. Rice brans, rice bran oils, and rice hulls: composition, food and industrial uses, and bioactivities in humans, animals, and cells.

    Science.gov (United States)

    Friedman, Mendel

    2013-11-13

    Rice plants produce bioactive rice brans and hulls that have been reported to have numerous health-promoting effects in cells, animals, and humans. The main objective of this review is to consolidate and integrate the widely scattered information on the composition and the antioxidative, anti-inflammatory, and immunostimulating effects of rice brans from different rice cultivars, rice bran oils derived from rice brans, rice hulls, liquid rice hull smoke derived from rice hulls, and some of their bioactive compounds. As part of this effort, this paper also presents brief summaries on the preparation of health-promoting foods including bread, corn flakes, frankfurters, ice cream, noodles, pasta, tortillas, and zero-trans-fat shortening as well as industrial products such bioethanol and biodiesel fuels. Also covered are antibiotic, antiallergic, anticarcinogenic, antidiabetic, cardiovascular, allelochemical, and other beneficial effects and the mechanisms of the bioactivities. The results show that food-compatible and safe formulations with desirable nutritional and biological properties can be used to develop new multifunctional foods as well as bioethanol and biodiesel fuel. The overlapping aspects are expected to contribute to a better understanding of the potential impact of the described health-promoting potential of the rice-derived brans, oils, and hulls in food and medicine. Such an understanding will enhance nutrition and health and benefit the agricultural and industrial economies. PMID:24175575

  18. 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.

  19. Research Advance on Allelopathy of Panax notoginseng%三七化感作用研究进展

    Institute of Scientific and Technical Information of China (English)

    李瑞博; 寻路路; 赵宏光; 崔秀明

    2012-01-01

    Allelopathy is one effective way to solve the continuous cropping obstacles ofpanax notoginseng. The development and progress of studies on the allelopathy ofpanax notoginseng in recent years and the allelopathy effect are reviewed from aspects of collecting and extracting methods,allelochemicals types currently known to exist and allelopathic extracts effects on panax notoginseng. The research progresses of allelopathy in panax notoginseng and the existing problems are discussed which will provide theoretical reference value for researchers working on allelopathy of panax notoginseng.%化感作用研究是解决三七连作障碍问题的有效途径之一.文章综述了近年来在三七化感方面的研究成果,从化感物质的收集提取方法到目前已知存在的化感物质种类、化感提取物对三七存在的化感效应.探讨了三七化感研究的发展现状及存在的不足,为进一步开展三七化感研究提供参考.

  20. Research Progress of Plant Allelopathy%植物化感作用研究进展

    Institute of Scientific and Technical Information of China (English)

    姚伶; 何开跃; 郭丽君; 郑纪伟

    2012-01-01

    Allelopathy universally exist in nature, involving botany, chemistry, ecology, physiology, microbiology and so on, which has significance on promoting agriculture sustainable development and eco-environment protection. At presenl there are many researches about plant allelopathy and most of the focus are harmful aspects. The species of allelochemical, action mode, mechanism, release ways and collection methods were reviewed, so as to provide reference value for the production practice.%化感作用普遍存在于自然界中,涉及植物学、化学、生态学、生理学和微生物学等学科,对促进农业可持续发展和生态环境保护有着十分重要的意义.目前,有关植物化感作用的研究报道较多,且大多偏重于植物化感作用的有害方面.该研究综述了化感物质的种类、作用方式、作用机制和化感物质的释放途径以及收集方法,以期为生产实践提供参考价值.

  1. 化感作用对土壤酶影响的研究进展%The Status on the Research of Allelopathy under the Influence of Soil Enzyme

    Institute of Scientific and Technical Information of China (English)

    方斯文; 张爱华; 贾明慧; 雷锋杰; 张连学

    2012-01-01

    Soil enzyme was the important part in soil ecosystem, studies on soil enzymes contribute to deepen our understanding of soil ecosystem degradation mechanism and material circulation and energy flow. Allelopathy has the important influence on soil micro ecology environment. This article reviewed the influence of allelochemicals on soil enzyme activity in recent years, and prospected the application of soil enzymology in allelopathy. In order to find more effective soil improvement program, it was raised from the perspective of allelopathy of soil enzyme activity.%土壤酶是土壤生态系统中的重要组成部分,土壤酶的研究有助于加深理解土壤生态系统的退化机理及其物质循环和能量流动.化感作用对土壤微生态环境有着重要影响.因此总结了近几年化感物质对土壤酶活性影响的主要研究成果,对土壤酶学在化感作用中的应用进行展望,提出从化感作用的角度研究土壤酶活性,从而找出更有效的土壤改良方案.

  2. 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

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    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.

  3. DISCUSS SEVERAL RESEARCHED PROBLEMS OF ALLELOPATHY IN SOYBEAN CONTINUOUS CROPPING BARRIER%论大豆连作障碍中有关化感作用(Allelopathy)研究的若干问题

    Institute of Scientific and Technical Information of China (English)

    阎飞; 韩丽梅; 杨振明

    2000-01-01

    本文着重地探讨了大豆连作障碍中有关化感作用研究应注意的若干问题,具体内容如下:(1)化感物质的提取源、提取剂及其收集方法的选取;(2)生物检测的参数、受体植物及其生长的环境基质的选用;(3)数据统计分析方法的选定等。以便为研究大豆连作障碍机理提供科学的方法。%Several problems as follow on allelopathic are mainly approached so as to supplyresearch methods on barrier mechanism of soybean continuous cropping (1) Selecting ex-traction sources, extracts and collection methods of allelochemicals; (2)Choose para-me-ters of bioassay, species of test plant and their growth ground substance; (3)Establish datastatistical analysis

  4. Study on Status of Allelopathy in Forestry%化感作用在林业中的研究现状

    Institute of Scientific and Technical Information of China (English)

    马艳丽

    2012-01-01

    The allelochemicals sources, types and collection methods were introduced in this paper. Allelopathic impact on tree growth and forest allelopathy manifestations of the two aspects described allelopathic effects of trees were studied. Then summarized the potential applications of allelopathy in forestry. Finally, the problems of allelopathy in forestry Research was point out. And the future research direction of allelopathy in forestry was prospected.%综合介绍了化感物质的来源、种类及收集方法,并分别从化感对林木生长的影响和林木化感作用表现形式两大方面阐述了林木的化感效应。接着对化感作用在林业上的应用潜力进行了归纳。最后指出目前林业研究化感作用所存在的问题,并对今后林业中化感作用的研究方向进行展望。

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Advances in studies on allelopathy of medicinal plants in China%我国药用植物化感作用研究进展

    Institute of Scientific and Technical Information of China (English)

    张爱华; 郜玉钢; 许永华; 雷锋杰; 张连学

    2011-01-01

    This review introduced the importance and significance of allelopathy in medicinal plant, analyzed the reasons for allelopathy in medicinal plant, described the types of allelochemicals, reviewed the research methods and clarified the mechanism of allelopathy, and investigated the main problems about allelopathic reaearches on medicinal plants. Based on those, the paper points out the problems in the current study on allelopathy of the medicinal plants.%介绍化感作用在药用植物研究中的重要性及意义,分析了药用植物产生化感作用的原因,综述药用植物中存在的化感物质种类及其化感作用研究方法,同时阐述了其化感作用产生的机制,并对药用植物化感作用研究中存在的主要问题进行了深入剖析,在此基础上指出药用植物化感作用研究需要加强的方向.

  7. 淡水水生植物化感控藻的研究进展%Research on Algalcontrol Ability of Allelopathy by Freshwater Macrophytes

    Institute of Scientific and Technical Information of China (English)

    胡建立; 周迟骏; 祈小丹; 周丽丽

    2012-01-01

    Algalcontrol ability of allelopathically is considered as one of the mechanisms that contribute to the stabilization of clear-water status in shallow lakes. The phylogeny of allelopathy on acquatic macrophytes was reviewed. The macrophyte species with anti-algal abilities were systematically summarized. The characteristics of anti-algal allelochemicals and the mechanism of the allelopathic of the allelopathic effect on algae were discussed. Subsequently, the algalcontrol mechanisms of allelopathy were explored, and the effects of environmental factors on phyto-allelopathic algae control were also demonstrated. Finally,application prospect of allelopathy in repair of aquatic ecological was prospected.%化感控藻是浅水湖泊保持清洁状态的机制之一.介绍了淡水高等水生植物化感作用的研究现状;总结了具有抑藻活性的水生植物种类;讨论了化感物质及其特性;对化感作用的抑藻机理进行了探索;阐述了环境因素对水生植物化感抑藻作用的影响;并且展望了化感作用在修复水生生态中的应用前景.

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

    Directory of Open Access Journals (Sweden)

    M. FARAVANI

    2008-08-01

    Full Text Available 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 materials with concentrations of 0, 50,100,150 and 200 gl-1 and at aqueous of oven dried materials extract with concentrations of 40,80,120,160,and 200 gl-1 .The crude methanol extracts were prepared using extract concentrations of 10.8,14.28 ,18 and 30 gl-1 of shoot and root materials. The extracts were tested with the widely used radish seed barnyard grass seed. Radish seed germination was inhibited at concentrations ranging from 200 gl-1 in the extract aqueous of dried materials and in the methanol extract concentrations of 14.28 and 30 gl-1 .The inhibition of root and shoot growth was also observed in the Barnyard grass seed. Both species were susceptible to allelopathy by extracts isolated from shoot and root of M. malabathricum and also their rate of germination, root length and shoot length in were decreased upon the application of both type of extractions. The results from this study strongly suggest that allelopathy may be a possible mechanism controlling the timing of barnyard grass germination and seedling establishment.

  9. Phytotoxic volatiles in the roots and shoots of Artemisia tridentata as detected by headspace solid-phase microextraction and gas chromatographic-mass spectrometry analysis.

    Science.gov (United States)

    Jassbi, Amir Reza; Zamanizadehnajari, Simin; Baldwin, Ian Thomas

    2010-12-01

    In the vicinity of big sagebrush (Artemisia tridentata), the growth of Nicotiana attenuata is negatively affected, in part due to the alleopathic effect of methyl jasmonate (MeJA) which is produced in large quantities by the aerial parts of sagebrush. Preliminary experiments suggested that growth-inhibiting substances were being emitted from the sagebrush roots. To identify the allelochemical secondary metabolites, we tested different root extracts in seedling growth bioassays with the naturally co-occurring native tobacco, Nicotiana attenuata, in a two-chamber Petri dish assay, optimized for tests of volatiles. Fractions rich in volatile compounds were particularly phytotoxic. We analyzed the volatiles emitted from the roots of intact Artemisia tridentata plants grown in soil, sand, and hydroponic cultures by using dynamic headspace extraction, headspace solvent-microextraction (HSME) and headspace solid-phase microextraction (HSPME), and GC-MS. Camphor, 1,8-cineol, nerol, and neryl isovalerate were phytotoxic and released as the major constituents. In addition to the phytotoxic monoterpenes, himachalenes, longifolene, caryophyllene, and acetylenic spiroethers, were found as characteristic components in the root's volatiles. The allelopathic potential of these root volatiles was compared with that of methyl jasmonate (MeJA), one of the most active compounds emitted from above-ground parts of the plant. PMID:21086024

  10. Phytotoxicity of umbelliferone and its analogs: Structure-activity relationships and action mechanisms.

    Science.gov (United States)

    Pan, Le; Li, Xiu-Zhuang; Yan, Zhi-Qiang; Guo, Hong-Ru; Qin, Bo

    2015-12-01

    Two coumarins, umbelliferone and daphnoretin, were isolated from roots of Stellera chamaejasme L; the former had been identified as one of the main allelochemicals in our previous studies. Both of them have the skeleton of 7-hydroxycoumarin, but showed different phytotoxic effects. Umbelliferone and its analogs were then prepared to investigate the structure-activity relationship of hydroxycoumarins and screened for phytotoxicity. The inhibitory effects varied observably in response to the coumarin derivatives, especially umbelliferone (1), 7-hydroxy-4-methylcoumarin (3) and coumarin (10) displayed strong inhibition of lettuce and two field weeds, Setaria viridis and Amaranthus retroflexus, and compounds 11 and 12 also exhibited phytotoxic activity with species specificity. The number and location of hydroxyl groups were importantly responsible for the phytotoxicity. A C7 hydroxyl group was considered to be a potentially active site and methyl substitution at the C4 position contributed significantly to the activity. The phytotoxic mechanism was briefly studied with umbelliferone by evaluating the reactive oxygen species (ROS) and chlorophylls level in lettuce seedlings. The results showed that umbelliferone induced the accumulation of ROS in the root tip and significantly decreased the chlorophyll content in the leaves. Thus, a ROS-mediated regulation pathway and the inhibition of photosynthesis were definitely involved in the phytotoxicity of umbelliferone. PMID:26509496

  11. 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

    2011-01-01

    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. PMID:22024957

  12. Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

    Science.gov (United States)

    Mallik, A. U.

    1995-09-01

    Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples of Calluna in western Europe, Kalmia in Newfoundland, and Gaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth of Calluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controlling Kalmia and Gaultheria, however, have yet to be developed. While the Kalmia- and Gaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range of Calluna heathlands of western Europe are being conserved as natural and seminatural vegetation.

  13. Allelopathic interference of aqueous extracts of chinaberry on the germination and initial growth of tomato

    Directory of Open Access Journals (Sweden)

    Lindamir Hernandez Pastorini

    2012-09-01

    Full Text Available Allelopathy effects vegetative development and is caused by chemical substances produced and released by surrounding plants. The objective of this work was to investigate the allelopathic activity of aqueous extracts of fresh and dried leaves and fruits of chinaberry (Melia azedarach L. – Meliaceae on the germination and initial growth of tomato. The extracts were prepared at concentrations of 1, 2 and 4% and analyzed for their pH and osmotic potential. The experiment consisted of four replications of 25 tomato seeds that were distributed in Petri dishes containing two sheets of germitest paper. Each plate received 2mL of an extract. The seeds were evaluated for percentage of germination (PG, germination rate (VG and germination speed index (IVG. The initial growth was assessed based on the length of the radicle, hypocotyl and leaf, and fresh and dry weight. All concentrations of the extracts exhibited inhibitory activity on germination and radicle growth, and the inhibitory effect increased as the concentration of the extract increased. Extracts from dried leaves had the greatest effects. The osmotic potential and pH of the extracts did not vary significantly compared to the control, indicating that the allelopathic effect was due to the allelochemicals in the extracts.

  14. Lutein sequestration and furanocoumarin metabolism in parsnip webworms under different ultraviolet light regimes in the montane west.

    Science.gov (United States)

    Carroll, Mark J; Berenbaum, May R

    2006-02-01

    Both biotic and abiotic selection pressures can contribute to geographic variation in allelochemical production in plants. We examined furanocoumarin production in western North American populations of Heracleum lanatum and Pastinaca sativa that, at different latitudes and altitudes, experience different ultraviolet (UV) light regimes. Total furanocoumarins and linear furanocoumarins of fruits were negatively correlated with UV irradiance, whereas amounts of angular furanocoumarins, which are generally less phototoxic, were not. Another factor potentially influencing furanocoumarin production is the presence of the parsnip webworm Depressaria pastinacella, (Lepidoptera: Oecophoridae), an herbivore that feeds on reproductive structures of both plant species. These insects sequester lutein from their host plants; this carotenoid acts to ameliorate furanocoumarin toxicity. Although the concentration of lutein in fruits did not vary with UV irradiance, lutein sequestration by sixth instars was positively correlated with UV irradiance. Webworm populations are variably infested with the polyembryonic webworm parasitoid Copidosoma sosares Walker (Hymenoptera: Encyrtidae). H. lanatum fruits from populations with webworms parasitized by C. sosares had lower concentrations of furanocoumarins, with the exception of sphondin, than fruits from plants infested with webworms free from parasitism. Lower levels of these furanocoumarins may reduce negative effects on the fitness of this parasitoid. In contrast with the variation in furanocoumarin content, the ability of webworms to metabolize furanocoumarins by cytochrome P450 did not differ significantly among populations from New Mexico to Alberta. PMID:16555136

  15. 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.

  16. 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.

  17. 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.

  18. Rhizobacteria activates (+)-δ-cadinene synthase genes and induces systemic resistance in cotton against beet armyworm (Spodoptera exigua).

    Science.gov (United States)

    Zebelo, Simon; Song, Yuanyuan; Kloepper, Joseph W; Fadamiro, Henry

    2016-04-01

    Gossypol is an important allelochemical produced by the subepidermal glands of some cotton varieties and important for their ability to respond to changing biotic stress by exhibiting antibiosis against some cotton pests. Plant growth-promoting rhizobacteria (PGPR) are root-colonizing bacteria that increase plant growth and often elicit defence against plant pathogens and insect pests. Little is known about the effect of PGPR on cotton plant-insect interactions and the potential biochemical and molecular mechanisms by which PGPR enhance cotton plant defence. Here, we report that PGPR (Bacillus spp.) treated cotton plants showed significantly higher levels of gossypol compared with untreated plants. Similarly, the transcript levels of the genes (i.e. (+)-δ-cadinene synthase gene family) involved in the biosynthesis of gossypol were higher in PGPR-treated plants than in untreated plants. Furthermore, the levels of jasmonic acid, an octadecanoid-derived defence-related phytohormone and the transcript level of jasmonic acid responsive genes were higher in PGPR-treated plants than in untreated plants. Most intriguingly, Spodoptera exigua showed reduced larval feeding and development on PGPR-treated plants. These findings demonstrate that treatment of plants with rhizobacteria may induce significant biochemical and molecular changes with potential ramifications for plant-insect interactions. PMID:26715260

  19. Research Progress on Garlic Allelopathy and Its Utilization%大蒜化感作用及其利用研究进展

    Institute of Scientific and Technical Information of China (English)

    丁海燕; 程智慧

    2014-01-01

    近年来关于大蒜化感作用的研究日益增多,它在农业生产中的利用潜力逐渐被人们发现。本文主要从大蒜化感现象的发现、化感作用机理、化感物质鉴定、化感作用利用以及化感作用研究方法等方面进行讨论,对大蒜化感作用研究存在的问题和发展方向进行综合评述。%In recent years,studies on Garlic(Allium sativum L.)allelopathic effect are increasing day by day. Its utilization in agricultural production has gradually been found out. This paper mainly focuses on the discussion about discovery of garlic allelopathy phenomena,allelopathy mechanism,identification of allelochemicals,allelopathy utilization,research methods,etc. The paper also conducts comprehensive review on existing problems and development direction of garlic allelopathy research.

  20. Development of a generalist predator, Podisus maculiventris, on glucosinolate sequestering and nonsequestering prey

    Science.gov (United States)

    van Geem, Moniek; Harvey, Jeffrey A.; Gols, Rieta

    2014-09-01

    Insect herbivores exhibit various strategies to counter the toxic effects of plant chemical defenses. These strategies include the detoxification, excretion, and sequestration of plant secondary metabolites. The latter strategy is often considered to provide an additional benefit in that it provides herbivores with protection against natural enemies such as predators. Profiles of sequestered chemicals are influenced by the food plants from which these chemicals are derived. We compared the effects of sequestration and nonsequestration of plant secondary metabolites in two specialist herbivores on the development of a generalist predator, Podisus maculiventris. Profiles of glucosinolates, secondary metabolites characteristic for the Brassicaceae, are known to differ considerably both inter- and intraspecifically. Throughout their immature (=nymphal) development, the predator was fed on larval stages of either sequestering (turnip sawfly, Athalia rosae) or nonsequestering (small cabbage white butterfly, Pieris rapae) prey that in turn had been feeding on plants originating from three wild cabbage ( Brassica oleracea) populations that have previously been shown to differ in their glucosinolate profiles. We compared survival, development time, and adult body mass as parameters for bug performance. Our results show that sequestration of glucosinolates by A. rosae only marginally affected the development of P. maculiventris. The effects of plant population on predator performance were variable. We suggest that sequestration of glucosinolates by A. rosae functions not only as a defensive mechanism against some predators, but may also be an alternative way of harmlessly dealing with plant allelochemicals.

  1. Allelopathic effects of aqueous extracts of sunflower on wheat (triticum aestivum l.) and maize (zea mays l.)

    International Nuclear Information System (INIS)

    Sunflower is a potent allelopathic plant which possesses important allelochemicals with known allelopathic activity on other plants. In this study, allelopathic effects of fresh aqueous extracts (FAE) and air dried aqueous extracts (DAE) of root, shoot and leaves of sunflower (Halianthus annuus L.) were investigated on germination and seedling growth of wheat (Triticum aestivum L.) and maize (Zea mays L.) in seed bioassay experiments carried out at Botany Department of Peshawar University during 2010. Results showed significantly inhibitory effects of aqueous extracts on seed germination, growth and dry biomass of seedlings of wheat and maize. In wheat seedlings, significant germination inhibition (15.21%), increased mean germination time (MGT) (57.76%), reduced plumule and radical growth (21.66 and 28.44%) and lowered seedlings dry biomass (31.05%) were recorded under dry aqueous extracts of leaf when compared to control. Germination percentage of maize was inhibited by dry aqueous extracts of leaf by 7.81%, germination index by 16.51%, increased MGT by 25.53%, decreased plumule and radical lengths by 29.00 and 36.12% respectively, and lowered maize seedling dry biomass by 34.02 %. In both experiments, dry aqueous extracts (DAE) were more phytotoxic than fresh aqueous extracts (FAE). Similarly, inhibitory effects of aqueous extracts of different parts of sunflower were recorded in the order leaf > shoot > root for both tested plants. (author)

  2. 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.

  3. 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. PMID:25075544

  4. Characterization of water dissolved organic matter under woody vegetation patches in semi-arid Mediterranean soils.

    Science.gov (United States)

    Cerdán, M; Sánchez-Sánchez, A; Jordá, J D; Amat, B; Cortina, J; Ruiz-Vicedo, N; El-Khattabi, M

    2016-05-15

    Woody patches in semiarid environments favor the establishment of other plants. Facilitation may be favored by an increase in soil fertility. Dissolved organic matter (DOM), is the most active fraction of soil organic matter and may contain compounds affecting plant establishment, as allelochemicals, hormone-like substances and metal carriers. However, information on DOM contents and composition in these environments is scarce. In this paper, we study the impact of woody patches on DOM in Stipa tenacissima L. steppes and discuss its implications for community dynamics. DOM under patch- and inter-patch areas, was analyzed for elemental composition, UV-Vis indices and organic acid content. Element concentration and composition in DOM, and organic acid concentration were similar in patch- and inter-patch areas. Yet, soils under patches were richer in DOC, aromatic species and organic acids (particularly fumaric acid) than soils in inter-patch areas. Dominant species affected organic matter concentration and quality in complex ways. Thus, patches dominated by Ephedra fragilis showed higher concentrations of TOC and aromatics than those dominated by other species. Rhamnus lycioides patches showed the highest accumulation of fumaric acid, which may contribute to its successful recruitment rate and expansion in the area. Our results show substantial differences in the amount and composition of DOM and specific compounds affecting soil functionality and plant dynamics. Further studies on the effects of such changes on seedling performance are needed to increase our understanding of plant-plant interactions in semiarid environments. PMID:26930307

  5. The carnivorous bladderwort (Utricularia, Lentibulariaceae): a system inflates.

    Science.gov (United States)

    Albert, Victor A; Jobson, Richard W; Michael, Todd P; Taylor, Derek J

    2010-01-01

    Carnivorous plants inhabit nutrient-poor environments, where prominent targets of prey capture are organic nitrogen and phosphorus. Some carnivorous plants also acquire carbon from their victims. A new report focusing on Utricularia, the bladderwort, demonstrates that carbon assimilated from photosynthesis is paradoxically secreted into the trapping environment, where it may help to support a mutualistic bacterial community. This bacterial community may also secrete allelochemicals that attract microcrustaceans which bear a strong overt resemblance to bladderwort traps. Furthermore, Utricularia and its sister genus Genlisea share anomalous molecular evolutionary features, such as highly increased rates of nucleotide substitution and dynamic evolution of genome size, from approximately 60-1500 megabases depending on the species or even population. A mechanistic hypothesis, based on the mutagenic action of reactive oxygen species (ROS) is proposed to underlie these phenomena, involving error-prone repair at the level of DNA bases and double-strand breaks. It is argued that these plants are prime candidates for further research on the complexities of plant physiology associated with carnivory, metagenomic surveys of trap microbial communities, novel plant nitrogen/nutrient utilization pathways, the ecology of prey attraction, whole-plant and trap comparative development, and, finally, evolution of the minimal angiosperm genome. PMID:20007200

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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).

  9. 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.

  10. Glutathione S-transferases of Aulacorthum solani and Acyrthosiphon pisum: partial purification and characterization.

    Science.gov (United States)

    Francis, F; Haubruge, E; Gaspar, C; Dierickx, P J

    2001-05-01

    Glutathione S-transferases (GST) play an important role in the detoxification of many substances including allelochemicals from plants. Brassicaceae plants contain glucosinolates and emit volatile isothiocyanates which affect the GST system. A comparison of the GST of two aphid species, the generalist Aulacorthum solani found on Brassicaceae and the Fabaceae specialist Acyrthosiphon pisum, was made to try to explain their respective feeding behaviour. Differences of GST were determined among the two aphid species based on purification by affinity chromatography, SDS-PAGE and on kinetic studies. Purification yields using an epoxy-activated Sepharose 6B column were highly different for the two aphid species (18% and 34% for A. solani and A. pisum, respectively). These variations were confirmed by SDS-PAGE. While only a 27-kDa band was observed for A. pisum, two bands of approximately 25-kDa were visualized for the generalist aphid, A. solani. Considering the kinetic results, differences of Km and Vmax were observed following the aphid species when a range of substrates (CDNB and DCNB) and GSH concentrations were tested. Studies on the detoxification enzymes of generalist and specialist herbivores would be undertaken to determine accurately the effect of the host plant on the organisms eating them, particularly in terms of biochemical and ecological advantages. PMID:11337260

  11. Effects of predation by Hydra (Cnidaria on cladocerans (Crustacea: Cladocera

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    Ligia Rivera-De la Parra

    2016-03-01

    Full Text Available Planktonic cladocerans have evolved different strategies to avoid predation from vertebrates; these include changes in morphology, behavior, physiology, and/or life-history traits. However, littoral cladocerans are better adapted to avoid invertebrate predation particularly from insect larvae by evolving morphological and physiological adaptations. Nevertheless, this has not been proven for some littoral predators such as Hydra. In this study, we provide quantitative data on how Hydra affects its zooplankton prey. We studied the predation behavior on Alona glabra, Ceridodaphnia dubia, Daphnia pulex, Daphnia cf. mendotae, Diaphanosoma birgei, Macrothrix triserialis, Moina macrocopa, Pleuroxus aduncus, Scapholeberis kingi, Simocephalus vetulus, Elaphoidella grandidieri, Brachionus rubens and Euchlanis dilatata. We also tested the indirect effect of allelochemicals from Hydra on the demography of Daphnia cf. mendotae. Littoral cladocerans are specially adapted to resist nematocyst injection and discharge of toxic substances from Hydra. A significant decrease in the population growth rate from 0.21 to 0.125 d-1 was observed at densities of 2 ind. ml-1. The role of carapace thickness as an adaptive strategy of littoral cladocerans against Hydra predation is discussed.

  12. Reduced herbicide doses in combination with allelopathic plant extracts suppress weeds in wheat

    International Nuclear Information System (INIS)

    Allelopathy is gaining popularity worldwide probably for decreasing the cost of production and environment friendly weed suppressing approach. Repeated field studies conducted during 2011-12 and 2012-13 at Agricutural Research Institute Tarnab, Peshawar, Pakistan where allelopathic water extracts of Oryza sativa, Parthenium hysterophorus, Phragmites australis and Datura alba along with reduced doses of phenoxaprop-p-ethyl and bromoxinil+MCPA were tested for controlling weeds in wheat. It was observed that weed density was encouragly suppressed whereas spike length (cm), number of spikelets spike-1 and 1000 grain weight (g) of the wheat were improved when the allelopathic plant water extracts were used in combination with lower doses of herbicides. Thus, allelochemicals provide weed suppressing option in wheat. However, more studies are required to fully explore the possibility of weed management and isolation of the chemicals involved in weed suppression for environment friendly weed management in wheat. Such studies may decrease the cost of crop production and total use of herbicides. (author)

  13. 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 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. PMID:27547360

  14. 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.

  15. 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.

  16. 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. PMID:17476467

  17. Assimilatory potential of Helicoverpa armigera reared on host (Chickpea) and nonhost (Cassia tora) diets.

    Science.gov (United States)

    Dawkar, Vishal V; Chikate, Yojana R; Gupta, Vidya S; Slade, Susan E; Giri, Ashok P

    2011-11-01

    Adaptation to plant allelochemicals is a crucial aspect of herbivore chemical ecology. To understand an insect ecology, we studied an effect of nonhost Cassia tora seed-based diet (Ct) on growth, development, and molecular responses in Helicoverpa armigera. We employed a comparative approach to investigate the proteomic differences in gut, hemolymph, and frass of H. armigera reared on a normal (chickpea seed-based, Cp) and Ct diet. In this study, a total of 46 proteins were identified by nano-LC-MS(E). Among them, 17 proteins were up-regulated and 29 proteins were down-regulated when larvae were exposed to the Ct diet. Database searches combined with GO analysis revealed that gut proteases engrossed in digestion, proteins crucial for immunity, adaptive responses to stress, and detoxification were down-regulated in the Ct fed larvae. Proteins identified in H. armigera hemolymph were found to be involved in defense mechanisms. Moreover, proteins found in frass of the Ct fed larvae were observed to participate in energy metabolism. Biochemical and quantitative real-time PCR analysis of selected candidate proteins showed differential gene expression patterns and corroborated with the proteomic data. Our results suggest that the Ct diet could alter expression of proteins related to digestion, absorption of nutrients, adaptation, defense mechanisms, and energy metabolism in H. armigera. PMID:21936543

  18. 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.

  19. Characterisation of aphid myrosinase and degradation studies of glucosinolates.

    Science.gov (United States)

    Francis, Frédéric; Lognay, Georges; Wathelet, Jean-Paul; Haubruge, Eric

    2002-08-01

    Myrosinase from Brevicoryne brassicae was purified by ammonium sulfate fractionation, dialysis, and chromatography on a DEAE column. The chromatography yielded a single peak and a 115.6-fold purification. Further FPLC gel filtration gave a single peak at 120 kDa. Denaturing SDS/PAGE of the protein revealed a single band at 60 kDa, indicating that the native B. brassicae myrosinase is a dimer. Kinetic parameters towards 8 glucosinolates were calculated. Strong differences of V(max) and K(m) were observed depending on the substrate. Degradation products of each glucosinolate were identified and quantified by GC-MS and GLC-FID, respectively. Using both crude aphid homogenates and purified myrosinase, two unique hydroxyglucosinolates, 3-butenyl- and benzyl-isothiocyanates were identified from progoitrin ((2S)-2-hydroxybut-3-enyl-glucosinolate) and sinalbin (4-hydroxybenzyl-glucosinolate) degradation respectively. Addition of ascorbic acid to the reaction mixtures containing sinalbin and progoitrin caused the production of hydroxylated degradation products usually associated with plant myrosinase metabolisation. The occurrence of the myrosinase system in B. brassicae is discussed in terms of similar allelochemical adaptation between the herbivore and its host plant. PMID:12125058

  20. Inhibition of insect glutathione S-transferase (GST) by conifer extracts.

    Science.gov (United States)

    Wang, Zhiling; Zhao, Zhong; Abou-Zaid, Mamdouh M; Arnason, John T; Liu, Rui; Walshe-Roussel, Brendan; Waye, Andrew; Liu, Suqi; Saleem, Ammar; Cáceres, Luis A; Wei, Qin; Scott, Ian M

    2014-12-01

    Insecticide synergists biochemically inhibit insect metabolic enzyme activity and are used both to increase the effectiveness of insecticides and as a diagnostic tool for resistance mechanisms. Considerable attention has been focused on identifying new synergists from phytochemicals with recognized biological activities, specifically enzyme inhibition. Jack pine (Pinus banksiana Lamb.), black spruce (Picea mariana (Mill.) BSP.), balsam fir (Abies balsamea (L.) Mill.), and tamarack larch (Larix laricina (Du Roi) Koch) have been used by native Canadians as traditional medicine, specifically for the anti-inflammatory and antioxidant properties based on enzyme inhibitory activity. To identify the potential allelochemicals with synergistic activity, ethanol crude extracts and methanol/water fractions were separated by Sephadex LH-20 chromatographic column and tested for in vitro glutathione S-transferase (GST) inhibition activity using insecticide-resistant Colorado potato beetle, Leptinotarsa decemlineata (Say) midgut and fat-body homogenate. The fractions showing similar activity were combined and analyzed by ultra pressure liquid chromatography-mass spectrometry. A lignan, (+)-lariciresinol 9'-p-coumarate, was identified from P. mariana cone extracts, and L. laricina and A. balsamea bark extracts. A flavonoid, taxifolin, was identified from P. mariana and P. banksiana cone extracts and L. laricina bark extracts. Both compounds inhibit GST activity with taxifolin showing greater activity compared to (+)-lariciresinol 9'-p-coumarate and the standard GST inhibitor, diethyl maleate. The results suggested that these compounds can be considered as potential new insecticide synergists. PMID:25270601

  1. A Stable-Isotope Mass Spectrometry-Based Metabolic Footprinting Approach to Analyze Exudates from Phytoplankton

    Directory of Open Access Journals (Sweden)

    Mark R. Viant

    2013-10-01

    Full Text Available 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 and analysed by high-resolution Fourier transform ion cyclotron resonance mass spectrometry. We used the harmful algal bloom forming dinoflagellate Alexandrium tamarense to prove the method. An algorithm was developed to automatically pinpoint just those metabolites with highly 13C-enriched isotope signatures, allowing us to discover algal exudates from the complex seawater background. The stable-isotope pattern (SIP of the detected metabolites then allowed for more accurate assignment to an empirical formula, a critical first step in their identification. This automated workflow provides an effective way to explore the chemical nature of the solutes exuded from phytoplankton cells and will facilitate the discovery of novel dissolved bioactive compounds.

  2. Evaluation of plant constituents associated with pecan phylloxera gall formation.

    Science.gov (United States)

    Hedin, P A; Neel, W W; Burks, M L; Grimley, E

    1985-04-01

    The weights of pecanCarya illinoensis Koch galls caused by several species ofPhylloxera (Homoptera: Phylloxeridae) were negatively correlated with leaf and nut weights and nut production. Several allelochemicals (isoquercitrin, juglone, and 2 proanthocyanidins) were isolated from galls, and their antibiotic potentials were estimated, based on their toxicity to the bacteriaPseudomones maltophilia (Hugh et Ryschenkow). Pecan proanthocyanidins (condensed tannins) were characterized for the first time, and their stereochemistry was elucidated. The protein and total sugar contents of total leaves and leaf surface washings were determined. The leaf surface sugar content was very low, suggesting that the puncturing strategy of this insect may be for the purpose of finding sugars. The plant growth hormones gibberellic acid, zeatin, zeatin riboside, kinetin, indole acetic acid, and abscisic acid were found in pecan leaves, stems, and their galls. Gibberellic and abscisic acids were present in highest concentrations in all tissues, but lower in galled tissues, suggesting that increased biosynthesis by pecan plant growth regulators did not occur in response to insect attack. PMID:24310069

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

    Science.gov (United States)

    Bacellar Mendes, Leonardo Brantes; Vermelho, Alane Beatriz

    2013-01-01

    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. PMID:24499580

  4. Allelopathic potential of oil seed crops in production of crops: a review.

    Science.gov (United States)

    Shah, Adnan Noor; Iqbal, Javaid; Ullah, Abid; Yang, Guozheng; Yousaf, Muhammad; Fahad, Shah; Tanveer, Mohsin; Hassan, Waseem; Tung, Shahbaz Atta; Wang, Leishan; Khan, Aziz; Wu, Yingying

    2016-08-01

    Agricultural production enhancement has been realized by more consumption of fossil energy such as fertilizer and agrochemicals. However, the production provides the present human with sufficient and diversified commodities, but at the same time, deprives in some extent the resources from the future human as well. In the other hand, it is known that synthetic herbicides face worldwide threats to human's health and environment as well. Therefore, it is a great challenge for agricultural sustainable development. The current review has been focussed on various oilseed crop species which launch efficient allelopathic intervention, either with weeds or other crops. Crop allelopathic properties can make one species more persistent to a native species. Therefore, these crops are potentially harmful to both naturalized as well as agricultural settings. On the other side, allelopathic crops provide strong potential for the development of cultivars that are more highly weed suppressive in managed settings. It is possible to utilize companion plants that have no deleterious effect on neighbor crops and can be included in intercropping system, thus, a mean of contributing to agricultural sustainable development. In mixed culture, replacement method, wherein differing densities of a neighbor species are planted, has been used to study phytotoxic/competitive effects. So, to use alternative ways for weed suppression has become very crucial. Allelochemicals have the ability to create eco-friendly products for weed management, which is beneficial for agricultural sustainable development. Our present study assessed the potential of four oilseed crops for allelopathy on other crops and associated weeds. PMID:27263104

  5. 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

    2016-01-01

    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). PMID:27173206

  6. 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.

  7. Allelopathic Potentialities of Gliricidia sepium and Acacia auriculiformis on the Germination and Seedling Vigour of Maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    M. B. Oyun

    2006-01-01

    Full Text Available Decline in crop yield in cropping and agroforestry system in recent years has been attributed to allelopathic effects. Plants may favourably or adversely affect other plants through allelochemicals, which may be released directly or indirectly from live or dead plants. The objective of this study was to examine and quantify the nature of interference of leaf leachates of Gliricidia sepium and Acacia auriculiformis on seed germination and seedling vigour of maize and to identify morphological trait for allelopathic interference assessment of maize seedlings. Leaf leachates of both Gliricidia and Acacia significantly decreased germination percentage and increased mean germination time (PGliricidia sepium perform the more inhibitory effect than Acacia auriculiformis. Shoot length (r = 0.792, root length (r = 0.920, shoot fresh weight (r = 0.873 and root dry weight (r = 0.828 were significantly correlated (P< 0.01 with SVI. Seedling root length appeared to be the strongest morphological trait for allelopathic assessment of maize seedling.

  8. Integrating novel chemical weapons and evolutionarily increased competitive ability in success of a tropical invader.

    Science.gov (United States)

    Zheng, Yu-Long; Feng, Yu-Long; Zhang, Li-Kun; Callaway, Ragan M; Valiente-Banuet, Alfonso; Luo, Du-Qiang; Liao, Zhi-Yong; Lei, Yan-Bao; Barclay, Gregor F; Silva-Pereyra, Carlos

    2015-02-01

    The evolution of increased competitive ability (EICA) hypothesis and the novel weapons hypothesis (NWH) are two non-mutually exclusive mechanisms for exotic plant invasions, but few studies have simultaneously tested these hypotheses. Here we aimed to integrate them in the context of Chromolaena odorata invasion. We conducted two common garden experiments in order to test the EICA hypothesis, and two laboratory experiments in order to test the NWH. In common conditions, C. odorata plants from the nonnative range were better competitors but not larger than plants from the native range, either with or without the experimental manipulation of consumers. Chromolaena odorata plants from the nonnative range were more poorly defended against aboveground herbivores but better defended against soil-borne enemies. Chromolaena odorata plants from the nonnative range produced more odoratin (Eupatorium) (a unique compound of C. odorata with both allelopathic and defensive activities) and elicited stronger allelopathic effects on species native to China, the nonnative range of the invader, than on natives of Mexico, the native range of the invader. Our results suggest that invasive plants may evolve increased competitive ability after being introduced by increasing the production of novel allelochemicals, potentially in response to naïve competitors and new enemy regimes. PMID:25367824

  9. Current research on plant allelopathy and its application in agricultural production%植物化感作用的研究现状及其在农业生产中的应用

    Institute of Scientific and Technical Information of China (English)

    杨田甜; 杜海荣; 陈刚; 邓鹏; 甄伟伟

    2012-01-01

    Allelopathy is commonly defined as the direct or indirect effects (stimulative or inhibitory) by one plant or another through production of chemical compounds that escape into environment, this phenomenon exists extensively in the agro-ecosystem, together with the plants' competition on light, water, nutrients and space, constitutes the interaction between different plants. In agricultural production, plant allelopathy influences the monoculture, crop rotation, crop cover, and takes an important role in getting rid of the obstacles of continuous cropping, regulating crops growth and preventing the pests and weeds and so on. In recent years, plant allelopathy was paid more attention by researchers all around the world. The categories, ways of releasing allelochemicals, and the research background, latest development, as well as the prospects of plant allelopathy applied in agricultural production were reviewed in this paper based on many references collected. Then the potential values in development of new varieties were also proposed. The further research in this field will be mainly focused on the cultivation of new allelopathic varieties which can avoid pests and suppress weeds as well as the application of plant-based pesticides. Furthermore, allelochemicals can be used as herbicides and the possibility of artificial synthesis will be investigated so that the pollution of chemical herbicides can be reduced. In the end, the existing problems and direction in the study on plants allelopathy were advanced.%植物化感作用体现了植物个体及群体之间生化相克相生的关系,它广泛地存在于农业生态系统之中,与植物对光、水分、养分和空间的竞争一起构成植物间以及与其他生物间的相瓦作用.文章在综合介绍植物化感作用研究背景、化感物质的种类、释放方式以及作用形式的基础上,系统地综述了近年来国内外有关植物化感现象的最新研究进展,并对植物化感作

  10. 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.

  11. 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.

  12. Research Advance on Allelopathy of Plant in Grassland Ecosystem%植物化感作用在草地生态系统中的研究进展

    Institute of Scientific and Technical Information of China (English)

    张玉娟; 唐士明; 邵新庆; 黄顶; 王堃

    2012-01-01

    植物的化感作用(allelopathy)是植物化学生态学研究的热点之一.在生态系统中化感植物通过淋溶、挥发、残体分解和根系分泌等过程,释放出化学物质,引起植物种间或种内的相互作用,产生有害或有利的影响.化感作用影响着群落的植物组成及分布格局、群落的演替、种子的保存和萌发以及氮循环等.主要对草地植物的化感物质种类、化感物质作用特点、释放途径、影响化感物质产生的因素以及化感物质提取方法进行了归纳和总结.同时,提出了草地植物化感研究存在的科学问题和应用前景.%Allelopathy of plant becomes one of hot topics in the field of plant chemical ecosystem. Chemical substances are released in environment via some processes, such as leaching, volatilization, residue decomposition and root exudation, producing interactions between plant species or in one species, which are positive or negative on surrounding plants and microorganisms. Allelopathy actions affect the community composition, distribution pattern, succession, the preservation and germination of seeds and the process of nitrogen circulation. The study mainly focused on the types, function characteristics, release ways, extract methods of allelochemical as well as the influence factors of production. It also proposed some scientific problems and application prospect in study on allelopathy of grassland plant.

  13. 陆生植物化感作用抑制藻类生长的研究进展%Review on Inhibition of Terrestrial Plant Allelopathy of Algae Growth

    Institute of Scientific and Technical Information of China (English)

    边归国

    2012-01-01

    Research of the plant allelopathy inhibition of algae growth is focused on aquatic plants, yet there are few researches on terrestrial plant. Terrestrial plants have the features of widely distributed, large biomass, easy cultivation, easy harvesting and easy processing. Many herbaceous and woody plants are rich in allelochemicals, which have prospect in the algae blooms inhibition and emergency response of the blooms. According to domestic and abroad research reports about terrestrial plant inhibition of algae growth, with sorting of herbaceous and woody, as well as classification of different plants, 15 families and 26Kinds of land plants allelopathy were evaluated.%目前关于植物化感抑制藻类生长的研究主要集中于水生植物,陆生植物对藻类化感作用的研究相对较少.陆生植物具有分布广泛、生物量大、便于培植、容易收割、加工方便等特点,许多草本植物和木本植物体内含有丰富的化感物质,在抑制水中藻类生长和应急处置水华等方面具有良好的应用前景.根据国内外近年来对陆生植物关于抑制藻类生长的研究报道,按草本和木本分类,并以植物的科划分,较全面地评述了15科26种陆生植物化感作用的研究进展.

  14. 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

  15. 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

  16. 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.

  17. Tritrophic effects of xanthotoxin on the polyembryonic parasitoid Copidosoma sosares (Hymenoptera: Encyrtidae).

    Science.gov (United States)

    Lampert, Evan C; Zangerl, Arthur R; Berenbaum, May R; Ode, Paul J

    2008-06-01

    Plant chemistry can have deleterious effects on insect parasitoids, which include the reduction in body size, increased development time, and increased mortality. We examined the effects of xanthotoxin, a linear furanocoumarin, on the polyembryonic encyrtid wasp Copidosoma sosares, a specialist parasitoid that attacks the parsnip webworm, Depressaria pastinacella, itself a specialist on furanocoumarin-producing plants. Furanocoumarins, allelochemicals abundant in the Apiaceae and Rutaceae, are toxic to a wide range of herbivores. In this study, we reared parasitized webworms on artificial diets containing no xanthotoxin (control) or low or high concentrations of xanthotoxin. Clutch sizes of both male and female C. sosares broods were more than 20% smaller when they developed in hosts fed the diet containing high concentrations of xanthotoxin. Xanthotoxin concentration in the artificial diet had no effect on the development time of C. sosares, nor did it have an effect on the body size (length of hind tibia) of individual adult male and female C. sosares in single-sex broods. Webworms fed artificial diets containing low or high concentrations of xanthotoxin were not significantly smaller, and their development time was similar to that of webworms fed a xanthotoxin-free diet. Mortality of webworms was not affected by xanthotoxin in their artificial diet. Therefore, dietary xanthotoxin did not appear to affect C. sosares via impairment of host health. However, unmetabolized xanthotoxin was found in D. pastinacella hemolymph where C. sosares embryos develop. Hemolymph concentrations were fourfold greater in webworms fed the high-xanthotoxin-containing diet than in webworms fed the low-xanthotoxin-containing diet. We failed to detect any xanthotoxin metabolism by either C. sosares embryos or precocious larvae. Therefore, the observed tritrophic effects of xanthotoxin are likely to be due to the effects of xanthotoxin after direct contact in the hemolymph rather than to

  18. 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. PMID:27522922

  19. 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.

  20. [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. PMID:27071248

  1. 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

  2. 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. PMID:27203687

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

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    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.

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

    Science.gov (United States)

    Sehlmeyer, Sven; Wang, Linzhu; Langel, Dorothee; Heckel, David G; Mohagheghi, Hoda; Petschenka, Georg; Ober, Dietrich

    2010-01-01

    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 and the

  5. cis-Cinnamic acid selective suppressors distinct from auxin inhibitors.

    Science.gov (United States)

    Okuda, Katsuhiro; Nishikawa, Keisuke; Fukuda, Hiroshi; Fujii, Yoshiharu; Shindo, Mitsuru

    2014-01-01

    The activity of cis-cinnamic acid (cis-CA), one of the allelochemicals, in plants is very similar to that of indole-3-acetic acid (IAA), a natural auxin, and thus cis-CA has long been believed to be an analog of auxin. We have reported some structure-activity relationships studies by synthesizing over 250 cis-CA derivatives and estimating their inhibitory activities on root growth inhibition in lettuce. In this study, the compounds that showed low- or no-activity on root growth inhibition were recruited as candidates suppressors against cis-CA and/or auxin and tested for their activity. In the presence of cis-CA, lettuce root growth was inhibited; however, the addition of some cis-CA derivatives restored control-level root growth. Four compounds, (Z)-3-(4-isopropylphenyl)acrylic acid, (Z)-3-(3-butoxyphenyl)acrylic acid, (Z)-3-[3-(pentyloxy)phenyl]acrylic acid, and (Z)-3-(naphthalen-1-yl)acrylic acid were selected as candidates for a cis-CA selective suppressor they allowed the recovery of root growth from inhibition by cis-CA treatment without any effects on the IAA-induced effect or elongating activity by themselves. Three candidates significantly ameliorated the root shortening by the potent inhibitor derived from cis-CA. In brief, we have found some cis-CA selective suppressors which have never been reported from inactive cis-CA derivatives for root growth inhibition. cis-CA selective suppressors will play an important role in elucidating the mechanism of plant growth regulation. PMID:24881667

  6. Experiments Testing the Causes of Namibian Fairy Circles.

    Directory of Open Access Journals (Sweden)

    Walter R Tschinkel

    Full Text Available The grasslands on the sandy soils of the eastern edge of the Namib Desert of Namibia are strikingly punctuated by millions of mostly regularly-spaced circular bare spots 2 to 10 m or more in diameter, generally with a margin of taller grasses. The causes of these so called fairy circles are unknown, but several hypotheses have been advanced. In October 2009, we set up experiments that specifically tested four hypothesized causes, and monitored these 5 times between 2009 and 2015. Grass exclusion in circles due to seepage of subterranean vapors or gases was tested by burying an impermeable barrier beneath fairy circles, but seedling density and growth did not differ from barrier-less controls. Plant germination and growth inhibition by allelochemicals or nutrient deficiencies in fairy circle soils were tested by transferring fairy circle soil to artificially cleared circles in the grassy matrix, and matrix soil to fairy circles (along with circle to circle and matrix to matrix controls. None of the transfers changed the seedling density and growth from the control reference conditions. Limitation of plant growth due to micronutrient depletion within fairy circles was tested by supplementing circles with a micronutrient mixture, but did not result in differences in plant seedling density and growth. Short-range vegetation competitive feedbacks were tested by creating artificially-cleared circles of 2 or 4 m diameter located 2 or 6 m from a natural fairy circle. The natural circles remained bare and the artificial circles revegetated. These four experiments provided evidence that fairy circles were not caused by subterranean vapors, that fairy circle soil per se did not inhibit plant growth, and that the circles were not caused by micronutrient deficiency. There was also no evidence that vegetative feedbacks affected fairy circles on a 2 to 10 m scale. Landscape-scale vegetative self-organization is discussed as a more likely cause of fairy circles.

  7. 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. PMID:26986929

  8. 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

  9. 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.

  10. Salivary proline-rich proteins in mammals: Roles in oral homeostasis and counteracting dietary tannin.

    Science.gov (United States)

    McArthur, C; Sanson, G D; Beal, A M

    1995-06-01

    We review information on the structure of proline-rich proteins (PRPs), their various functions related to oral homeostasis and dietary tannin, and the structural basis of these functions. Consideration of the multifunctional nature of these salivary proteins helps explain both the subtle and large variations found in structure and secretion rates both within individuals and between species. We propose that the ancestral function of PRPs is in maintaining oral homeostasis and that counteracting dietary tannins by binding with them is a derived function. PRPs are effective in oral homeostasis at low secretion levels, whereas counteracting tannin depends on high secretion levels. In the dietary habits ranging from carnivores through omnivores to exclusively planteaters, the dietary nitrogen level is progressively reduced, and plant allelochemical intake, including tannins, increases. We suggest that during this evolution from meat-eater to plant-eater, there was some point in omnivory at which selective pressure from nitrogen limitations, arising from a low nitrogen/high tannin diet, became sufficiently great for the evolution of increased secretion level and diversification of PRPs for dealing with tannin. If this hypothesis is correct, carnivorous mammals should secrete low levels of PRPs for oral homeostasis, but should never secrete high levels, unless they are secondarily carnivorous. Omnivores consuming a diet of very little animal tissue but higher levels of tannin-containing foliage or fruit should generally have the capacity to produce high levels of salivary PRPs. Browsers and frugivores should also produce high levels of PRPs, but grazers may have reduced secretion rates depending on the antiquity of the dietary habit. This hypothesis is consistent with the limited information available on the abundance, type, and distribution of PRPs in mammals. Studies are suggested which would test the functional and evolutionary arguments presented. PMID:24234312

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

    Directory of Open Access Journals (Sweden)

    Md Abdullah Yousuf Al Harun

    Full Text Available 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

  12. 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. PMID:26961755

  13. Effects of sorghum (sorghum bicolor L. root exudates on the cell cycle of the bean plant (phaseolus vulgaris L. root

    Directory of Open Access Journals (Sweden)

    Hallak Angela Maria Gattás

    1999-01-01

    Full Text Available Two experiments were conducted to test the allelopathic effect of sorghum (Sorghum bicolor L. root exudates on bean (Phaseolus vulgaris L. cell division. Research was conducted in the greenhouse of the Wistock Agricultural Research Institute of Minas Gerais State (EPAMIG and in a laboratory of the Federal University of Lavras (UFLA. Sorghum variety BR-601 and bean variety Carioca MG were used. The exudate, called sorgoleone (SGL, was obtained by methylene chloride and acetic acid extraction from sorghum roots seven days after sowing on Petri dishes, and refrigerated until use. Solutions of 0.01, 0.05, 0.10, and 0.15 mM were prepared using Johanson solution as the SGL solvent. Seven-day-old bean seedlings grown in vermiculite in a greenhouse were transplanted to the solution. Seven days after transplantation, the beans did not show any sign of phytotoxicity; however, cytogenetic observations showed that SGL reduced the number of cells in prophase, metaphase, and anaphase stages. Colchicine effects were observed among cells in metaphase on the third and fifth days after treatments and varied with SGL concentrations. By the seventh day, the colchicine effects were inversely proportional to concentration, which varied from 34.3% for 0.01 mM to 6.6% for 0.15 mM. SGL acts as a mitotic inhibitor. It probably depolymerizes the microtubular proteins and induces the formation of colchicine metaphases causing polyploid nuclei. A largest period of SGL treatment also induced chromosome breaks and bridge formation in anaphase and telophase. Although SGL cannot be used as a herbicide for bean cultures, its allelochemical effects on other cultures are the factors that will define the use of sorghum as a natural herbicide.

  14. 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.

  15. α-蒎烯对黄曲条跳甲的拒避作用%Repellency of α-pinene against stripped flea beetle,Hyllotreta striolata(F)

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    拒避性异种他感物质有可能作为21世纪对环境友好的植物保护剂用于农业害虫的防治.采用四臂嗅觉仪、室内笼罩试验和田间试验相结合的方法,研究了松节油的主要成份α-蒎烯,对黄曲条跳甲的拒避作用,并用干扰作用控制指数方法进行了评价.结果表明:在实验室,不同的浓度下,其拒避作用最大可达95.45%, 相应的干扰作用控制指数(IIPC)为0.05;在笼罩试验条件下,最大拒避作用的强度为91.60%,IIPC为0.09;而田间小区试验中,最大拒避作用下降到54.48%,IIPC则为0.46.拒避作用与浓度正相关.采用上述系列方法有助于开展拒避性植物保护剂的规范化研究.%Repellant allelochemicals could be the 21st century environmentally friend ly plant protectants applied in agricultural pest control. Α-pinene, a monoter pene,was evaluated for repellent activity against Phyllotreta striolata in a four-armed olfactometer, flight-chamber and field tests. In the laboratory, repellency reached 95.45% with a corresponding IIPC of 0.05 in olfactometry; in the flight-chamber trial,repellency and IIPC were 91.60% and 0.09, respectiviely. In the field, however, repellency and IIPC were reduced to 54.48% and 0.46, respectively. Overall, dilution-dependent repel lency was exhibited in all methods; and increasing dilution elicited decreased repellency and hence protection.

  16. 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

  17. IDENTIFITION AND STUDY ON ALLELOPATHY OF SOYBEAN ROOT EXUDATES%大豆根分泌物的鉴定及其化感作用的初步研究

    Institute of Scientific and Technical Information of China (English)

    韩丽梅; 李国权

    2000-01-01

    采用GC-MS分析法,鉴定了由水培试验方法获得的2周、8周大豆根分泌物的二氯甲烷提取物,并对其化感作用进行了初步研究。结果表明:能被二氯甲烷提取出来的根分泌物有有机酸类、醇类、酯类、酮类、醛类、酚类、苯类、烃类等有机化合物,其中包含一些资料报道过的化感物质。与对照比较,2周、8周大豆根分泌物对大豆种子萌发、8周根分泌物对胚根生长未表现出显著抑制作用,但2周根分泌物对胚根生长却表现出极显著的化感抑制作用。上述结果表明,大豆根分泌物中存在化感物质,2周与8周大豆根分泌物的种类和数量有所不同。本文还探讨了大豆根分泌物的化感作用及大豆根分泌物与大豆连作障碍的关系等问题。%Compounds extracted with dichloromethane from soybean rootexudates for two weeks, eight weeks in water-culture were identified and allelopathy were studied by GC-MS analysis. The results showed that: The soybean root exudates extracted with dichloromethane included organic acide, alcohol, ester, acetone, aldehyde, phenol, pheyl, hydrocarbon and so on. Many of which were reported as allelochemicale. Contrast with control, the influence of the soybean root exudates for two weeks, eight weeks on the germination of soybean seeds, for eight weeks on radicle growth did not show significant allelopathy inhibition. But the allelopathy of the soybean root exudates for two weeks on soybean radicle growth showed significant inhibition. The results showed that the allelochemicals exist in the soybean root exudates. The varieties and quantities of soypean root exudates for two weeks are different with those for eight weeks. In addition, the alleleopathy of soybean root exudates and the relationship between soybean root exudates and barrier on soybean continuous and alternate cropping were discussed.

  18. 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.

  19. 新千年的挑战:第三届世界植物化感作用大会综述

    Institute of Scientific and Technical Information of China (English)

    孔垂华

    2003-01-01

    @@ 1 引言 近30年来,化学生态学已逐步建立了独立的学科体系,并愈来愈受到重视和不断取得进展.1975年国际化学生态学会(International Society of Chemical Ecology, ISCE)成立,并正式出版会刊Journal of Chemical Ecology.国际化学生态学会关注的4个主要研究领域是:1)种内信息素(pheromone); 2)化学通讯(chemical communication);3)种间化学传导和化感物质 (Allelochemical);4)植物化感作用 (Allelopathy).因此,植物化感作用一直是化学生态学研究的主重要内容之一.1994年,世界从事植物化感作用研究的科学家成立了独立的国际植物化感作用学会(International Allelopathy Society, IAS), 出版会刊Allelopathy Journal, 并决定每三年在各大洲举行一次世界植物化感作用大会.1996年在欧洲西班牙召开了第一次大会,1999年在北美洲加拿大召开了第二次大会,第三届世界植物化感作用大会于2002年8月26~30日在亚洲日本科学城筑波举行,作者在国家自然科学基金和第三次世界植物化感作用大会组委会的资助下,应邀出席了大会.现将会议情况作一综述,并就国际植物化感作用研究中的问题和对策表明作者的看法和认识.

  20. Photosynthetic electron-transfer reactions in the gametophyte of Pteris multifida reveal the presence of allelopathic interference from the invasive plant species Bidens pilosa.

    Science.gov (United States)

    Zhang, Kai-Mei; Shen, Yu; Zhou, Xiao-Qi; Fang, Yan-Ming; Liu, Ying; Ma, Lena Q

    2016-05-01

    To date, the response of the fern gametophyte to its environment has received considerable attention. However, studies on the influence of plant invasion on the fern gametophyte are fewer. Allelopathy has been hypothesized to play an important role in biological invasion. Hence, it is necessary to study the allelopathy of invasive plant species to the fern gametophyte and elucidate the mechanisms by which invasive plants cause phytotoxicity. As one of the main invasive plants in China, Bidens pilosa exhibits allelopathic effects on the gametophytic growth of Pteris multifida. The root exudate plays an important role among various allelochemical delivery mechanisms in B. pilosa. The effect invasive plant species has on photosynthesis in native species is poorly understood. To elucidate this effect, the changes in photosynthesis in the gametophytes of P. multifida are analyzed to examine the mechanisms of the root exudates of B. pilosa. Meanwhile, a non-invasive plant, Coreopsis basalis, was also applied to investigate the effects on fluorescence and pigments in P. multifida gametophytes. We found that gametophytes exposed to both B. pilosa and C. basalis had decreased fluorescence parameters in comparison with the control, except for non-photochemical quenching. Furthermore, it was found that these parameters were markedly affected from day 2 to day 10 in the presence of both exudates at a concentration of 25% or above. B. pilosa exudate had a negative dose-dependent effect on chlorophyll a, chlorophyll b, carotenoid, and the total chlorophyll in the gametophyte. The inhibitory effects increased with increasing exudate concentrations of both species, exhibiting the greatest inhibition at day 10. In conclusion, B. pilosa irreversibly affected the photosynthesis of P. multifida on both PS I and PS II. Root exudates caused the primary damage with respect to the decrease of the acceptors and donors of photon and electron in photosynthetic units and the production and

  1. 化感作用在水土保持生物措施治理中的应用研究%Review on Allelopathy in the Application of Biological Measures of Soil and Water Conservation Management

    Institute of Scientific and Technical Information of China (English)

    陆茜; 张金池

    2013-01-01

    植物的化感作用是植被以小分子有机物为媒介调控种间和种内关系的机制,近年在水土保持生物措施中得到研究和应用。综述国内外化感作用在水土保持生物措施中的研究进展和应用潜力,重点评述化感作用在林地连栽障碍问题中的重要性和解决路径以及化感作用在优化植被结构中的应用;提出基于化感品种和化感物质数据库无缝对接基础数据库形成林草措施方案专家系统的设想。化感作用的研究方法和实验设计上需要充分模拟或结合实际生境,综合其它重要生态因子,使研究结果更可信和具有解释力。%Plant allelopathy is a sort of regulation mechanism for interspecific and intraspecific relations of vegetations with small molecule organic media ,which increasingly took place in the researches and applications of biological measures for soil and water conservation .The research developments and applicated potentials of plant allelopathy on biological measures in the soil and water conservation were reviewed ,underlining the vital role allelopathy plays in soil degradations ,its resolution and ,the optimizations of structure of vegetations .An en-vision about grass measures expert system was developed based on allelopathic species and allelochemicals da -tabases as well as their seamless connections to some basic databases .Plant allelopathy can not be separated as single significant factor from complex ecological processes .Research methods and experimental designs should be simulated or combine with natural habitats sufficiently and consolidate other important ecological factors to make the results more credible and explanatory .

  2. 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

  3. 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

  4. 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

  5. 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.

  6. Allelopathic potential of Crinum americanum under different extractions conditionPotencial alelopático de Crinum americanum L. sob diferentes condições de extração

    Directory of Open Access Journals (Sweden)

    Maria Inês Salgueiro Lima

    2011-07-01

    Full Text Available The long-term use reduces the efficiency of the traditional herbicides. The use of plant-extracted natural substances is an alternative more efficient and less aggressive to the environment. The allelochemicals of several species are considered to be possible plants for developing an organic herbicide. One of the major problems in this sense is obtaining botanical material in commercial quantities. Improving the extraction techniques is an important step, once it reduces the amount of botanical material needed. In this survey was tested several methods of aqueous extractions of dried leaves of Crinum americanum L., an Amarilidaceae with strong allelopathic properties. The time of extraction is not important for the allelopathic potential of the extracts. On the other hand, when the temperature during extraction was 40 e 60oC, leaded to extracts with stronger allelopathic potential. It is possible to improve the allelopathic potential using the filtered matter more than once.O uso prolongado torna os herbicidas tradicionais cada vez menos eficientes no combate às plantas daninhas. O uso de substâncias naturais extraídas das plantas é uma alternativa eficiente e menos agressiva ao meio ambiente. Os aleloquímicos de muitas espécies são possíveis matérias primas para o desenvolvimento de herbicidas orgânicos. Um dos principais problemas encontrados para a produção desses herbicidas é a obtenção de material botânico em quantidade comercial. Melhorar as técnicas de extração é um passo importante, uma vez que reduz a quantidade de matéria prima necessária. Nesse trabalho foram testados diversos tipos de extrações aquosas de folhas secas de Crinum americanum L., uma Amarilidacea com forte potencial alelopático. O tempo de extração é pouco importante para o potencial alelopático do extrato. Por outro lado, temperaturas de extração de 40 e 60oC levaram à produção de extratos que inibiram mais eficientemente a germina

  7. Ingredients for protist coexistence: competition, endosymbiosis and a pinch of biochemical interactions.

    Science.gov (United States)

    Müller, Johann P; Hauzy, Céline; Hulot, Florence D

    2012-01-01

    1. The interaction between mutualism, facilitation or interference and exploitation competition is of major interest as it may govern species coexistence. However, the interplay of these mechanisms has received little attention. This issue dates back to Gause, who experimentally explored competition using protists as a model [Gause, G.F. (1935) Vérifications expérimentales de la théorie mathématique de la lutte pour la vie. Actualités Scientifiques et Industrielles, 277]. He showed the coexistence of Paramecium caudatum with a potentially allelopathic species, Paramecium bursaria. 2. Paramecium bursaria hosts the green algae Chlorella vulgaris. Therefore, P. bursaria may benefit from carbohydrates synthesised by the algae. Studying endosymbiosis with P. bursaria is possible as it can be freed of its endosymbiont. In addition, C. vulgaris is known to produce allelochemicals, and P. bursaria may benefit also from allelopathic compounds. 3. We designed an experiment to separate the effects of resource exploitation, endosymbiosis and allelopathy and to assess their relative importance for the coexistence of P. bursaria with a competitor that exploits the same resource, bacteria. The experiment was repeated with two competitors, Colpidium striatum or Tetrahymena pyriformis. 4. Results show that the presence of the endosymbiont enables the coexistence of competitors, while its loss leads to competitive exclusion. These results are in agreement with predictions based on resource equilibrium density of monocultures (R*) supporting the idea that P. bursaria's endosymbiont is a resource provider for its host. When P. bursaria and T. pyriformis coexist, the density of the latter shows large variation that match the effects of culture medium of P. bursaria. Our experiment suggests these effects are because of biochemicals produced in P. bursaria culture. 5. Our results expose the hidden diversity of mechanisms that underlie competitive interactions. They thus support

  8. Mechanisms for regulating oxygen toxicity in phytophagous insects.

    Science.gov (United States)

    Ahmad, S; Pardini, R S

    1990-01-01

    The antioxidant enzymatic defense of insects for the regulation of oxygen toxicity was investigated. Insect species examined were lepidopterous larvae of the cabbage looper (Trichoplusia ni), southern armyworm (Spodoptera eridania), and black swallowtail (Papilio polyxenes). These phytophagous species are subject to both endogenous and exogenous sources of oxidative stress from toxic oxygen radicals, hydrogen peroxide (H2O2) and lipid peroxides (LOOH). In general, the constitutive levels of the enzymes superoxide dismutase (SOD), catalase (CAT), glutathione transferase (GT), and its peroxidase activity (GTpx), and glutathione reductase (GR), correlate well with natural feeding habits of these insects and their relative susceptibility to prooxidant plant allelochemicals, quercetin (a flavonoid), and xanthotoxin (a photoactive furanocoumarin). Induction of SOD activity which rapidly destroys superoxide radicals, appears to be the main response to dietary prooxidant exposure. A unique observation includes high constitutive activity of CAT and a broader subcellular distribution in all three insects than observed in most mammalian species. These attributes of CAT appear to be important in the prevention of excessive accumulation of cytotoxic H2O2. Unlike mammalian species, insects possess very low levels of a GPOX-like activity toward H2O2. Irrefutable proof that this activity is due to a selenium-dependent GPOX found in mammals, is lacking at this time. However, the activity of selenium-independent GTpx is unusually high in insects, suggesting that GTpx and not GPOX plays a prominent role in scavenging deleterious LOOHs. The GSSG generated from the GPOX and GTpx reactions may be reduced to GSH by GR activity. A key role of SOD in protecting insects from prooxidant toxicity was evident when its inhibition resulted in enhanced toxicity towards prooxidants. The role of antioxidant compounds in protecting these insects from toxic forms of oxygen has not been explored in

  9. Effect of Potato Continuous Cropping on Soil Physicochemical Properties and Soil Enzyme Activity%马铃薯连作对土壤理化性质及酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    杜茜; 马琨

    2013-01-01

      In order to reveal the mechanism of the potato continuous cropping obstacle ,maintain a healthy farm-land ecosystem environment ,thus to ensure the safety of the potato crop ,the influence of potato continuous cropping on soil physicochemical properties and enzyme activity were studied .The results showed that the con-tent of organic matter ,total nitrogen ,total phosphorus ,available potassium ,available P ,alkali solution nitrogen were all increased ,there were significant difference between them except for organic matter content and availa-ble P content ,and the soil pH significantly reduced .After soil steam sterilization ,the activity of soil urease , phosphatase and catalase were extremely significantly reduced .Soil urease activity and catalase activity were in -creased when soil adding potatoes residues .Thus the soil of potato continuous cropping might contain allelo-chemicals .%  为了揭示马铃薯连作障碍产生的机理,维护健康的农田生态系统环境,从而保障马铃薯的产量安全,采用盆栽试验研究马铃薯连作对土壤理化性质和酶活性的影响。结果表明:马铃薯连作土壤湿热灭菌添加马铃薯残茬后,有机质、全氮、全磷、速效钾、速效磷、碱解氮含量均有所提高,除有机质和速效磷含量差异不显著外,其余含量具有极显著差异,且土壤 pH 显著降低。连作土壤湿热灭菌后,土壤脲酶、磷酸酶、过氧化氢酶活性均极显著降低。连作土壤添加马铃薯残茬后,土壤脲酶和过氧化氢酶活性升高,由此说明马铃薯连作土壤中可能含有化感自毒物质。

  10. 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

  11. 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.

  12. 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

  13. 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

  14. Allelopathic effect of black mustard tissues and root exudates on some crops and weeds Efeito alelopático de tecidos de mostarda-preta e exsudatos da raiz de algumas culturas e plantas daninhas

    Directory of Open Access Journals (Sweden)

    E Al-Sherif

    2013-03-01

    Full Text Available Laboratory and greenhouse experiments were conducted to evaluate the phytotoxic effect of black mustard extracts and root exudates on two crops: Trifolium alexandrinum and Triticum aestivum, and two weeds: Phalaris paradoxa and Sisymbrium irio. The seeds were treated with aqueous and ethanolic extracts and chloroform for eight days, or subjected to root exudates of just harvested mustard in a greenhouse for five weeks. High-performance liquid chromatography (HPLC was used to quantify phytotoxins from plant tissues. Seed germination of P. paradoxa was reduced with the lowest concentration of the different extracts. However, the aqueous extract at 4% completely curtailed the germination of all the target species. In general, plant extracts had a concentration-dependent reduction of seedling growth of the target species. However, the ethanolic extract, at the lowest concentration, has stimulated the shoot length of both T. alexandrinum and T. aestivum, and the root length of the former. Mustard root exudates inhibited emergence and growth of the target species throughout the experiment. Ferulic and syringic acids were the dominant allelochemicals found when HPLC was used.Experimentos de laboratório e estufa foram realizados para avaliar o efeito fitotóxico dos extratos de mostarda-preta e exsudatos de raiz de duas culturas: Trifolium alexandrinum e Triticum aestivum, bem como de duas plantas daninhas: Phalaris paradoxa e Sisymbrium irio. As sementes foram tratadas com extratos aquosos, etanólicos e clorofórmio por oito dias, ou submetidas a exsudatos de raiz de mostarda recém-colhidaem estufa durante cinco semanas. A cromatografia líquida de alto desempenho (HPLC foi usada para a quantificação de fitotoxinas a partir de tecidos de plantas. Sementes de P. paradoxa apresentam germinação reduzida com a menor concentração dos diferentes extratos. No entanto, o extrato aquoso a 4% restringiu completamente a germinação de todas as esp

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

    International Nuclear Information System (INIS)

    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-1), GA (2.65 mg L-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, and PSII in

  16. 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

  17. 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

  18. N-苯基-2-萘胺对青菜生长及 AsA-GSH 循环影响研究%Effects of N-phenyl-2-naphthylamine on the Growth and AsA-GSH Circulation Metabolism in Chinese Cabbage

    Institute of Scientific and Technical Information of China (English)

    薛延丰; 冯慧芳; 石志琦; 严少华

    2013-01-01

    effect.The shoot height and fresh weight significantly increased compared with the control in the different sampling periods .However,when the concentration of N-phenyl-2-naphth-ylamine was more 0.50 mg/L,the shoot height and biomass remarkably decreased with the increase of N-phenyl-2-naphthylamine concentration.The contents of reduced ascorbate (AsA),dehydroascorbate(DHA),total Vc and ratio of AsA/DHA had the same trends.In the treatments of 0.50 mg/L,contents of AsA,DHA,total Vc and ratio of AsA/DHA significantly increased compared with the control .When the concentration of N-phenyl-2-naphthylamine was more 0.50 mg/L,the contents of total Vc,AsA,DHA and ratio of AsA/DHA remarkably decreased with the in-crease of N-phenyl-2-naphthylamine concentration .In the AsA cycle, the activities of ascorbic acid peroxidase (APX),dehydroascorbate reductase(DHAR)and monodehydroascorbate reductase (MDHAR) had the same change trends.All the activities showed the increase firstly and then showed the decrease with the increase of N -phenyl-2-naphthylamine concentration,especially,in the treatment of 0.50 mg/L,whereas the ascorbate oxidase(AAO) pres-ented the gradually decrease trend with the increase of N-phenyl-2-naphthylamine concentration.The treatment of 0.25 mg/L had the best effect about the AAO activity .The content of oxidized glutathione (GSSG) showed a little decrease compared with the control in the GSH cycle when the concentration was lower than 2.50 mg/L.It showed no difference compared with the control .But the reduced glutathione (GSH) content and the glutathione reductase (GR) appeared the increase firstly and then the decrease with the increase of N-phenyl-2-naphthylamine concentra-tion.The treatment of 0.50 mg/L had the best effect.All the results suggested that to reasonable use the allelochem-icals in Water hyacinth could promote the growth ,enhance AsA-GSH circulation metabolism and maintain higher antioxidative stress capacity in the Chinese cabbage .

  19. 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

  20. Allelopathic effect of Commelina benghalensis root exudates%火柴头根系分泌物的化感效应

    Institute of Scientific and Technical Information of China (English)

    杨田甜; 杜海荣; 陈刚; 邓鹏; 甄伟伟

    2011-01-01

    在农田生态系统中,作物晚发弱苗的部分原因是杂草向作物生长周围环境释放化感物质.本研究以疏水性根渗出液连续收集法(C RETS)收集火柴头根系分泌物,在室内采用培养皿滤纸和砂培法分别研究了火柴头根系分泌物对4种常见农作物种子萌发、幼苗生长的化感作用.结果表明:火柴头根系分泌物对高粱、玉米、绿豆和油菜具有不同程度的化感效应,化感效应响应强度由强到弱的顺序为:油菜>玉米>绿豆>高梁.对种子萌发和幼苗生长也存在明显的浓度效应,总体上呈现出低浓度(≤0.025 g·mL-1)促进,高浓度( ≥0.050 g·mL-1)抑制的现象,且随着处理浓度的增加抑制作用逐渐增强.%In the farmland ecosystem, one reason for the crop's postponed seed germination and weak seedling was attributed to the influence of allelochemicals released from the weeds. The root exudates of Commelina benghalensis were collected with a continuous trapping system. The allelopathic effects of the root exudates from Commelina benghalensis L on four crops - Sorghum vulgare, Zea mays, Vigna radiate and Brassica napus were investigated in seed germination and seedling growth with petri-dish and sand cultivation. The results showed that the root exudates from C. benghalensis had different allelopathic effects on the four crops, and varied with crop species in the descending order of Brassica napus > Zea mays > Vigna radiate > Sorghum vulgare. Allelopathic index of seed germination and seedling growth depended on the concentration of root exudates, that is, when the concentration was lower than 0. 025 g.mL-1 , the germination and seedling growth of acceptors were promoted. While the concentration was over 0. 050 g . mL-1~ , they were inhibited, and the level of inhibition was improved with the increase of the root exudates concentration. In conclusion, Brassica napus was inhibited more strongly than the other species at the same

  1. Seleção indireta para teor de 2-tridecanona em tomateiros segregantes e sua relação com a resistência à traça-do-tomateiro Indirect selection to 2-tridecanone content and its relation to tomato pinworm resistance

    Directory of Open Access Journals (Sweden)

    Cláudia Regina Gontijo Labory

    1999-05-01

    Full Text Available Este trabalho teve como objetivo verificar a relação entre o teor de 2-tridecanona (2-TD em materiais selecionados e o nível de resistência à traça-do-tomateiro (Tuta absoluta (Meyrick, 1917 (Lepidoptera: Gelechiidae em gerações avançadas de Lycopersicon spp. derivado de cruzamentos interespecíficos. Foi usada uma população de tomateiros segregantes (geração F4RC2 para 2-TD, uma metilcetona que confere resistência à traça-do-tomateiro. Genótipos foram selecionados e avaliados quanto à resistência do tipo não-preferência: três materiais com alto teor do aleloquímico 2-TD (HI1, HI2, HI3 e dois materiais com baixo teor (LO1, LO2, além das testemunhas. Após infestação controlada, foram avaliados: contagem do número de ovos postos, evolução da lesão nos folíolos, porcentagem de folíolos atacados, e índice geral de lesão causada pela traça. Plantas com alto teor de 2-TD (HI1 e HI3 tiveram uma baixa progressão das lesões ocasionadas pelo ataque de T. absoluta. A planta LO1 foi muito atacada pela praga, o mesmo não ocorrendo com a planta LO2, que foi infestada acidentalmente por ácaros do gênero Tetranychus, acarretando, provavelmente, uma disputa de nicho ecológico entre os dois artrópodes. Concluiu-se que altos teores de 2-TD estão ligados a mecanismos de resistência à traça-do-tomateiro do tipo não-preferência por oviposição e alimentação.This work had the objective to verify the relation between 2-tridecanone (2-TD in selected plants and resistance level to tomato pinworm (Tutaabsoluta (Meyrick, 1917 (Lepidoptera: Gelechiidae in advanced generations of Lycopersicon spp. interspecific crosses. It was used a tomato population (F4RC2 generation segregant for 2-TD, a methyl ketone that controls the resistance of the tomato pinworm. Materials were selected and evaluated for a non-preference mechanism of resistance. Three genotypes with high level of the allelochemic 2-TD (HI1, HI2, HI3, two with low

  2. 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

  3. 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

  4. 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

  5. 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%

  6. The effect of allelopathy on the competition and succession between Skeletonema costatum and Prorocentrum donghaiense%化感作用对中肋骨条藻与东海原甲藻竞争演替的影响

    Institute of Scientific and Technical Information of China (English)

    王江涛; 李慧; 曹婧; 张议文

    2012-01-01

    为了检验化感作用对赤潮藻类生长和竞争的影响,对中肋骨条藻滤液进行了培养实验,结果显示中肋骨条藻滤液对其自身的生长呈现出化感抑制现象,而且抑制作用在磷限制条件下尤为显著.自化感作用的程度与藻的生长阶段有关,指数期滤液对中肋骨条藻的抑制作用比衰亡期滤液略强.不同滤液添加比例实验进一步验证了中肋骨条藻自化感作用的存在.降解实验表明在某些机制的作用下,化感物质会随时间而发生降解.在所有的滤液培养实验中,中肋骨条藻对东海原甲藻的生长没有明显影响,这可能是由于东海原甲藻对滤液中的化学物质有较强的耐受能力.中肋骨条藻滤液的共培养实验结果显示,中肋骨条藻与东海原甲藻表现出演替现象,东海原甲藻最终获得竞争优势.实验结果表明化感作用可能会影响中肋骨条藻和东海原甲藻的竞争演替.%Culture filtrates of Skeletonema costatum were tested to verify the effects of allelopathy on the growth of algae. S. Costatum growth was inhibited, especially in P limiting cultures. The filtrates of S. Costatum in exponential phase exhibited significantly inhibitory effect on the growth of its own compared with the controls, which was stronger than that of declining phase filtrates, hence, allelopathic effect was connected with the growth phase of algae. The filtrates with different ratios showed different inhibitory degrees to S. Costatum itself, and the ratio was higher the inhibition was stronger. In degradation experiments, the dramatic decrease of inhibitory effect on S. Costatum was observed. A possible explanation for this might be that allelopathic compounds in S. Costatum cultures could be degraded. In addition, during all filtrate experiments, the growth of P. Donghaiense was not affected, which might because of the tolerance of P. Donghaiense to these allelochemicals in S. Costatum filtrates. Furthermore

  7. 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

  8. Behaviour and chemical ecology of Bactrocera flies

    International Nuclear Information System (INIS)

    . Semiochemicals are divided into ecomone and para-ecomone, the former is released naturally into the environment, the latter is not. An ecomone with intraspecies activity is known as a pheromone. One with interspecies activity is generally grouped under allelochemicals. It is specifically known as: 1) an allomone when it benefits the releaser with detrimental effect on the receiver, 2) a kairomone when it benefits the receiver with detrimental effect on the releaser, 3) a synomone when it benefits both the releaser and receiver, or 4) an apneumone when released from dead or decaying material caused by microbial action. A para-ecomone may be either a constituent of an organism or a synthetic chemical not released naturally. It should be emphasised that a chemical can be an ecomone and a para-ecomone and, as an ecomone, may act as a pheromone as well as an allomone or a kairomone. The study of an organism's ecomone in relation to the environment, interaction between individuals belonging to the same and/or different species, and how it affects behaviour constitutes the bulk of chemical ecology. Ecomones in applied entomology may be exploited as agents for 1) insect pest surveillance and monitoring, 2) trapping insect in population estimation or as an intervention technique such as the area-wide male annihilation technique, and 3) understanding and disrupting insect communication in a pest control or management programme. This paper presents an update of the behaviour within the context of chemical ecology of Bactrocera flies which is crucial in the understanding the flies' role in the complex communal interrelationships within Malaysian agro- and natural ecosystems as previously presented (Tan 1993)

  9. 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.

  10. 栽参土壤提取物活性组分筛选及其对人参幼苗生理效应研究%Study on Screening of Active Constituents from Extracts on Soil Cultivated Ginseng and Their Effects on Physiology of Ginseng Seedling

    Institute of Scientific and Technical Information of China (English)

    邵财; 郭靖; 许世泉; 王志清; 王英平

    2012-01-01

    Two methods were applied in the study that used different chemical reagents (Ethyl acetate, Water-saturated N-butanol) to extract aquatic extracts from cultivated ginseng soil and directly used different chemical reagents (Ethyl acetate, N-butanol, Methanol, Distilled water) to extract cultivated ginseng soil. Activity of each constituent was determined with ginseng seeds. Root vigor and MDA content of ginseng seedling was determined after treated with higher activity constituents. The results showed that each constituent of extracts from cultivated ginseng soil had effects on radicles growth of ginseng seeds in various degree, and inhibited effects were strengthened with concentration increasing. Both ethyl acetate phase of aquatic extracts and ethyl acetate extracts from cultivated ginseng soil manifested stronger inhibited effects, and both constituents had significant effects on rool vigor and MDA content of ginseng seedling. The content of MDA increased 23.8% and 37.5%, respectively, which was dramatically different from that of control(P<0.01). The root vigor decreased 17.2% and 27.1%, respectively, which was significantly lower than that of control (P<0.01). Thus, it is an effective approach that we extract cultivated ginseng soil with ethyl acetate to gain a part of ginseng allelochemicals, which could promote root cell membrane lipid peroxidation and increase membrane permeability, and reduce root activity of ginseng seedling and influence its growth and development.%研究了栽参土壤水提取液用不同化学试剂(乙酸乙酯、水饱和正丁醇)萃取和直接采用不同化学试剂(乙酸乙酯、正丁醇、甲醇和蒸馏水)提取,对所得各个组分以人参种子为试材进行生物活性测定,经筛选所得活性较强组分再以人参幼苗为试材进行其根系活力和丙二醛含量测定.结果表明:栽参土壤提取液不同组分均对人参种子胚根生长有不同程度的影响,抑制作

  11. 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

  12. Research Progress on Allelopathic Effects of Terrestrial Plants for Inhibitting Harmful Algae%陆生植物化感作用抑制有害藻应用研究进展

    Institute of Scientific and Technical Information of China (English)

    王聪; 张饮江; 李岩; 文晓峰; 董悦; 刘晓培; 马海峰

    2012-01-01

    The inhibitory allelopathy of plants on algae aroused extensive concern because of its high efficiency and selective character of inhibitting harmful algae,as well as harmless to the environment.lt is expected to be a valuable and safe ' alternative for algal bloom control with the intensive study .The progress of the inhibition on the harmful algae by allelopathy was introduced, the evaluation methodology of allelopathic effect were analyzed from aspects of algae cell density, chlorophyll content, growth and metabolism and ultrastmcture, antioxidant enzyme activities. The inhibition of water boom algae and red tide algae by terrestrial plants were mainly described, Some herbaceous plants such as crops and medicinal herb as well as some ligneous plants such as common trees were included in these terrestrial plants.The antialgal compounds in these terrestrial plants were explored and analyzed,which provide theoretical guidence for developing new algistat. The potential value of inhibiting filamentous algae by allelochemicals was further discussed, which achieved diversity of algal-inhibiting objects.The problem of allelopathy by terrestrial plants were pionted out and the prospect of allelopathic algae control was put forward.%植物化感物质由于对藻类抑制的高效性和选择作用性,以及对环境无污染等特点而备受关注,有望成为具有应用价值的安全性生物抑藻技术.文章探究了利用植物化感作用抑制有害藻类生长的进展,从藻细胞密度、叶绿素含量、超微结构及生长代谢、抗氧化酶活性等方面分析了化感抑藻作用效果的评价方法,重点阐述了陆生植物对水华藻、赤潮藻主要藻种的抑制作用,包括草本植物中一些农作物和药用植物以及木本植物中的常见树木,同时对这些陆生植物中所含抑藻物质开展了探索与分析,为开发新的抑藻制剂提供理论指导,深入讨论了陆生植物化感物质抑

  13. 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

  14. Up in smoke: II. Germination ofNicotiana attenuata in response to smoke-derived cues and nutrients in burned and unburned soils.

    Science.gov (United States)

    Baldwin, I T; Morse, L

    1994-09-01

    Nicotiana attenuata is a native tobacco that is commonly found usually one growing season after fires in the blackbrush, sagebrush and pinyon-juniper forests of the Great Basin desert of North America. This plant also occurs in isolated dry washes and roadsides for many consecutive seasons. Postfire annuals are thought to synchronize their germination from the seed bank with the postfire environment in response to increases in (1) fire-related cues or (2) nutrient supply rates resulting from the mineralization of nutrients by fire, or (3) the removal of allelochemicals produced by the dominant vegetation occupying the sites before the burn or the microbial community associated with the dominant vegetation. We examine the effect of these three changes on the germination ofN. attenuata seed from artificial seed banks made with burned and unburned soil taken in 1993 from under four dominant shrub species (Coleogyne ramosissima, Yucca baccata, Lycium andersonnii, Purshia tridentata) of an area that burned in 1992 and from two dry washes in whichN. attenuata populations have persisted since at least 1988. We utilize our recent discovery that aqueous extracts of wood smoke contain potent germination cue(s) for this species and the established observation that nitrate stimulates germination in manyNicotiana species. In two experiments, we added smoke-derived germination cues and nutrients separately and in combinations to the artificial seed banks, measured germination rates, and inferred the effect of burning by the response of the seed banks to these additions. Germination rates of seed in burned soil were consistently higher than those in unburned soil collected from under all species tested; concentrations of nitrate, P, Mn, and Ca were also higher in burned than unburned soils. Because the addition of more cue and nitrate to burned soil increased germination rates, these soil components may not be at concentrations sufficient to saturate the germination response one

  15. Effects of leachates from Casuarina equisetifolia on growth and physiological and biochemical characteristics of Terminalia catappa seedlings%木麻黄浸提液对榄仁树幼苗生长及生理生化的影响

    Institute of Scientific and Technical Information of China (English)

    冯剑; 刘强; 王瑾; 罗炘武; 阮长林; 张晓楠

    2016-01-01

    In this study, we tried to introduce Terminalia catappa into coastal Casuarina equisetifolia windbreak to form mixed forest as windbreak, so as to improve efficiency of wind sheltering and sand fixation and the regional ecological envi-ronment. We selected Terminalia catappa of seedling age of 15 d as experimental and irrigate allelochemicals of leachates of Casuarina equisetifolia of concentration of 125 g•L-1 from roots, rhizosphere soil and litter, and studied the effects of allel-opathy of C. equisetifolia on growth, photosynthesis, the damage of membrance system, antioxidant enzyme activity system and proline content of T. catappa seedlings in growing period of 60 d. The results showed that the leachates of roots, litter and rhizosphere soil reduced the survival rates and damaged seedlings of the beginning of the treatment, and significantly af-fected the plant height, leaves, roots biomass of Terminalia catappa seedlings. Therefore, we could deduce that influence plant growth by the composition of different leachates of Casuarina equisetifolia. All the three leachates significantly reduced the net photosynthesis(Pn), stomatal conductance(Ccond), inter cellular CO2 concentration(Ci),transpiration rate(Tr), but significantly increased the water use efficiency(WUE) of the seedlings after 15-45 d since the treatment beginning. No significant effect of leachates from C. equisetifolia on the leaf chlorophyll contents of Terminalia catappa seedling of treat-ment beginning, with the prolong of growth period, but the roots leachates of C. equisetifolia significantly reduced chloro-phyll content of seedling. The seedlings growth period of 60 d, all the three leachates significantly increased the cell mem-brane penetrability and proline content (Pro), but the roots leachate significantly increased the stomatal conductance, inter cellular CO2 concentration, superoxide dismutase in leaves and catalase in roots of T. catappa. The litter leachates increased the stomatal

  16. 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

  17. 外源酚酸类物质对马铃薯植株生长发育的影响及机制研究%Study on the Effects and Mechanism of Exogenous Phenolic Acids on Potato′s Growth and Development

    Institute of Scientific and Technical Information of China (English)

    李自龙; 回振龙; 张俊莲; 沈宝云; 李朝周

    2013-01-01

    探讨了外源酚酸类物质对马铃薯植株生长发育的影响及其机制。对羟基苯甲酸、香草酸和阿魏酸这3种酚酸类化合物是连作马铃薯土壤中重要的化感物质,分别浇灌这3种酚酸的溶液及其混合液对马铃薯植株的株高、茎粗、地上分茎数、匍匐茎数、根长和生物量皆有显著抑制作用,且混合酚酸溶液的抑制效果大于相同浓度的这3种酚酸溶液中任一溶液。结果还显示,外源酚酸处理显著降低了马铃薯植株的根系活力、叶片叶绿素含量和叶片净光合速率,且上述作用随着酚酸溶液质量浓度(从50 mg/L至200 mg/L)增加而显著增加,这些影响对于植株的生长发育可能具有直接且重要的作用。关于叶片脂质过氧化程度的检测表明,150,200 mg/L外源酚酸处理显著提高了叶片的MDA含量,并对应着抗氧化酶活性的整体下降,并以混合酚酸的效果最为显著;可见,150,200 mg/L的外源酚酸溶液处理可对马铃薯叶片产生持续而明显的胁迫,并造成抗氧化酶系统功能的下降及膜质过氧化程度的增加,这一结果与前述外源酚酸抑制植株的生长发育、根系活力和叶片光合速率是相对应的,上述研究结果对于从感化物质累积的角度理解及调控马铃薯连作障碍具有一定的价值。%This paper probed the effects and mechanism of exogenous phenolic acids on potato ′s growth and de-velopment .Para hydroxy benzoic acid ,vanillic acid and ferulic acid are the three most important allelochemicals ( phe-nolic acids ) in potato continuous cropping soil ,when the potato seedlings were irrigated with the three kinds of phe-nolic acids solution and its mixture respectively ,the plant height,stem diameter,aerial stem number,stolon number and root length were reduced significantly ,and at the same concentration of phenolic acid solution ,the inhibition of the their mixture was stronger than

  18. EFFECT OF N-PHENYL-2-NAPHTHYLAMINE ON THE GROWTH, ANTIOXIDATIVE ENZYME AND PSⅡINCYLINDROSPERMOPSIS RACIBORSKII%N-苯基-2-萘胺对拟柱胞藻生长、抗氧化酶及光合系统Ⅱ的影响

    Institute of Scientific and Technical Information of China (English)

    刘瑞; 白芳; 冉小飞; 杨燕君; 杨宋琪; 施军琼; 吴忠兴

    2015-01-01

    In this study, we investigated the effects of N-phenyl-2-naphthylamine, a type of allelochemical, on the inva-sive cyanobacteriaCylindrospermopsis raciborskii. We measured the growth, the activities of antioxidative enzymes, and polyphasic Chl.a fluorescence transients ofCylindrospermopsis raciborskii that was cultured in the presence of N-phenyl-2-naphthylamine at different concentrations (0, 0.05, 0.10, 0.50, 1.00 and 2.00 mg/L). When the concentration of N-phenyl-2-naphthylamine was higher than 0.50 mg/L, the Chl.a content was significantly lower than the control. This indicated that the level of Chl.a could be reduced by the increase in N-phenyl-2-naphthylamine. TheEC50 of N-phenyl-2-naphthylamine onC. raciborskii was 1.02 mg/L after a 72h exposure. At the concentration lower than 0.50 mg/L, N-phenyl-2-naphthylamine caused a significant increase in a variety of parameters of polyphasic Chl.a fluorescence transients, including the maximum quantum yield of primary photochemistry (φPo), the density of RCs(RC/CSo), the performance index on absorption basis (PIABS), and the performance index on cross section basis (PICS). One exception wasψo that declined in the presence of low concentration of N-phenyl-2-naphthylamine. On the other hand,φPo,RC/CSo,PIABS,PICS,andψo were all reduced when the concentration of N-phenyl-2-naphthylamine was higher than 0.50 mg/L (eg. 1.00 mg/L and 2.00 mg/L). These data suggested that low dose of N-phenyl-2-naphthylamine might promote the photosynthetic efficiency ofC. raciborskii, while high dose could reduce density of RCs and harm the PSⅡ and electron transfer, and thus result in the inhibition of photosynthetic efficiencyinC. raciborskii. Compared to the control, the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) were all obviously elevated along with the increase in N-phenyl-2-naphthylamine concentration. This implied thatC. raciborskii might counter the damage of N-phenyl-2

  19. Allelopathic Effects and Chemincal Components of the Volatiles from Cedrus deodara Leaves and Branches%雪松枝叶挥发性物质的化感作用及其化学成分分析

    Institute of Scientific and Technical Information of China (English)

    李晓凤; 焦慧; 袁艺; 田胜尼

    2015-01-01

    Allelopathy of the volatiles from isolated leaves and branches of C. deodara to seed germination of Brassica pekinensis, Raphanus sativus and Lactuca sativa were studied in a semi-closed container. The componenets of llelochemicals were determined by GC-MS. The results indicated that germination rate and dry weight of B. pekinensis, R. sativus and L. sativa were not significantly affected by the natural volatiles released by the leaves and branches of C. deodara, but seedling growth was significantly inhibited. The volatile oil from leaves and branches of C. deodara had significant inhibitory effects on the germination rate, germination index, root length and seedling length of seeds of these three vegetables. Germination rate and germination index of L. sativa were inhibited by 92.85%and 96.43%, respectively, while root length of B. pekinensis were inhibited by 51.3%, suggesting that there were potential allelochemicals in the natural volatiles released by the leaves and branches of C. deodara that inhibited seed germination, and that the allelopathic effect of volatile oil was stronger than natural volatile compounds. The chemical components of volatile oil and natural volatile were analyzed. In particular, 37 volatile chemical compounds were identified in volatile oil and 84.64%of these volatiles were α-pinene(24.72%), β-pinene(21.04%) and Caryophyllene(12.42%). 22 volatile chemical compounds were identified in the natural volatile and 52.81% of them were terpenes. The main components were α-pinene(17.16%), β-pinene(11.53%) and Bicyclo[3.1.0]hex-2-ene, 4-methyl-1-(1-methylethyl)-(13.06%). Both the volatile oil and natural volatile shared, but the volatile oil had relatively high terpene content. The components and chemical profile of volatile oil were both more than that of natural volatile, which might be a reason for the stronger allelopathic effect of volatile oil than than that of natural volatile. Seen from the results of analysis, terpenes were the

  20. Henosepilachna vigintioctopunctata susceptibility to Ttripterygium wilfordii and Datura stramonium extracts%茄二十八星瓢虫对雷公藤和曼陀罗提取物的敏感性

    Institute of Scientific and Technical Information of China (English)

    李保同; 闫超; 平新亮; 汤丽梅

    2012-01-01

    suppressed by T. Wilfordii and D. Stramonium extracts, that of AChE of larvae fed on eggplants and tomatoes was obviously suppressed and yet that of AChE activity of larvae fed on nightshades was relatively suppressed. CarE activity of larvae fed on nightshades, that of MFO of larvae fed on potatoes were significantly restrained by T. Wilfordii and D. Stramonium extracts. The induction or restraint of detoxification enzymes by allelochemicals in host plants were the main possible reasons for the differences in pesticide susceptibilities of H. Vigintioctopunctata larvae.%为研究寄主植物对茄二十八星瓢虫药剂敏感性及体内酶活力的影响,采用浸渍法分别测定了取食茄子、马铃薯、番茄和龙葵的茄二十八星瓢虫幼虫(以下简称幼虫)对雷公藤和曼陀罗提取物的敏感性,用生化方法测定了雷公藤和曼陀罗提取物对幼虫体内乙酰胆碱酯酶(AChE)和主要解毒酶活性的影响.结果表明,雷公藤提取物对取食茄子、马铃薯、番茄和龙葵的幼虫LC50值分别为1.407 9 mg·L-1、1.595 8 mg·L-1、1.464 7 mg·L-1和1.109 7 mg·L-1,相对毒力指数为78.82、69.54、75.76和100;曼陀罗提取物对取食茄子、马铃薯、番茄和龙葵的幼虫LC5o值分别为0.6417 mg·L-1、0.610 3 mg·L-1、0.758 0 mg·L-1和0.488 3 mg·L-1,相对毒力指数为76.09、80.01、64.42和100;取食龙葵的幼虫对2种植物提取物的敏感性显著高于取食茄子、马铃薯和番茄的幼虫.取食4种寄主植物的幼虫体内靶标酶AChE和主要解毒酶谷胱甘肽-S-转移酶(GST)、羧酸酯酶(CarE)、多功能氧化酶(MFO)活力顺序均为茄子>马铃薯>番茄>龙葵.其中,取食番茄和龙葵的幼虫体内AChE和GST活力显著低于取食茄子和马铃薯的幼虫,取食马铃薯、番茄和龙葵的幼虫CarE活力显著低于取食茄子的幼虫,取食4种寄主植物的幼虫MFO活力差异达极显著水平.雷公藤和曼陀罗提取物对幼虫体内AChE和GST