WorldWideScience

Sample records for allelopathy

  1. Proving allelopathy in crop-weed interactions

    Science.gov (United States)

    Allelopathy (plant/plant chemical warfare) is difficult to prove, especially when competition for resources is the dominant component of plant/plant interference (interference = allelopathy +competition). This paper describes experimental approaches for proving allelopathy and points out common pit...

  2. Phenolics and plant allelopathy.

    Science.gov (United States)

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

    2010-12-07

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

  3. 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.

  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. 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

  6. A Simple Demonstration of Allelopathy.

    Science.gov (United States)

    Marcus, Bernard A.; Burz, Judy

    1994-01-01

    Uses members of the Cruciferae family such as radishes (Sp. Raphanus), to describe a process termed allelopathy by which a plant uses a chemical compound that escapes into the environment to harm another plant. Tips are provided for easy use in the classroom. (ZWH)

  7. Sorghum allelopathy – from ecosystem to molecule

    Science.gov (United States)

    Sorghum allelopathy has been reported in a series of field experiments following sorghum establishment. In recent years, sorghum phytotoxicity and allelopathic interference have also been well-described in greenhouse and laboratory settings. Observations of allelopathy have occurred in diverse loca...

  8. The ecosystem and evolutionary contexts of allelopathy.

    Science.gov (United States)

    Inderjit; Wardle, David A; Karban, Richard; Callaway, Ragan M

    2011-12-01

    Plants can release chemicals into the environment that suppress the growth and establishment of other plants in their vicinity: a process known as 'allelopathy'. However, chemicals with allelopathic functions have other ecological roles, such as plant defense, nutrient chelation, and regulation of soil biota in ways that affect decomposition and soil fertility. These ecosystem-scale roles of allelopathic chemicals can augment, attenuate or modify their community-scale functions. In this review we explore allelopathy in the context of ecosystem properties, and through its role in exotic invasions consider how evolution might affect the intensity and importance of allelopathic interactions.

  9. Dose-response-a challenge for allelopathy?

    Science.gov (United States)

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

    2005-04-01

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

  10. Mathematical Modelling of Allelopathy: IV. Assessment of Contributions of Competition and Allelopathy to Interference by Barley.

    Science.gov (United States)

    Liu, De Li; An, Min; Johnson, I R; Lovett, J V

    2005-04-01

    One of the main challenges to the research on allelopathy is technically the separation of allelopathic effect from competition, and quantitatively, the assessment of the contribution of each component to overall interference. A simple mathematical model is proposed to calculate the contribution of allelopathy and competition to interference. As an example of applying the quantitative model to interference by barley (Hordeum vulgare cv. Triumph), the approach used was an addition of allelopathic effect, by an equivalent amount, to the environment of the test plant (white mustard, Sinapis alba), rather than elimination of competition. Experiments were conducted in glasshouse to determine the magnitude of the contributions of allelopathy and competition to interference by barley. The leachates of living barley roots significantly reduced the total dry weight of white mustard. The model involved the calculation of adjusted densities to an equivalent basis for modelling the contribution of allelopathy and competition to total interference. The results showed that allelopathy contributed 40%, 37% and 43% to interference by barley at 6, 12 and 18 white mustard pot(-1). The consistency in magnitude of the calculated contribution of allelopathic effect by barley across various densities of receiver plant suggested that the adjusted equivalent density is effective and that the model is able to assess the contribution of each component of interference regardless of the density of receiver plant.

  11. The role of momilactones in rice allelopathy.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Peters, Reuben J

    2013-02-01

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

  12. [Book reviews] The Science of Allelopathy, edited by A. R. Putnam and C. Tang; Allelopathy, by E .L. Rice

    Science.gov (United States)

    Keeley, J.E.

    1988-01-01

    Review of: Putnam, Alan R., and Chung-Shih Tang (eds.). 1986. The science of allelopathy. Wiley-Interscience Publications, John Wiley and Sons, New York. xi + 317 p. $52.50. Rice, Elroy L. 1984. Allelopathy. Second Edition. Academic Press, New York. xi + 422 p. $71.00.

  13. An Aromatic Adventure with Allelopathy: Using Garlic to Study Allelopathy in the Classroom

    Science.gov (United States)

    Shimabukuro, Mary A.; Haberman, Vickie

    2006-01-01

    In this paper, the authors explore the potential of garlic ("Allium sativum L.") to illustrate the concept of allelopathy and demonstrate the biological activity of plant volatiles. This article describes several classroom experiments involving garlic that can be used as a method of introducing students of various ages to the following important…

  14. The role of allelopathy in agricultural pest management.

    Science.gov (United States)

    Farooq, Muhammad; Jabran, Khawar; Cheema, Zahid A; Wahid, Abdul; Siddique, Kadambot H M

    2011-05-01

    Allelopathy is a naturally occurring ecological phenomenon of interference among organisms that may be employed for managing weeds, insect pests and diseases in field crops. In field crops, allelopathy can be used following rotation, using cover crops, mulching and plant extracts for natural pest management. Application of allelopathic plant extracts can effectively control weeds and insect pests. However, mixtures of allelopathic water extracts are more effective than the application of single-plant extract in this regard. Combined application of allelopathic extract and reduced herbicide dose (up to half the standard dose) give as much weed control as the standard herbicide dose in several field crops. Lower doses of herbicides may help to reduce the development of herbicide resistance in weed ecotypes. Allelopathy thus offers an attractive environmentally friendly alternative to pesticides in agricultural pest management. In this review, application of allelopathy for natural pest management, particularly in small-farm intensive agricultural systems, is discussed.

  15. Competing phytoplankton undermines allelopathy of a bloom-forming dinoflagellate.

    Science.gov (United States)

    Prince, Emily K; Myers, Tracey L; Naar, Jerome; Kubanek, Julia

    2008-12-07

    Biotic interactions in the plankton can be both complex and dynamic. Competition among phytoplankton is often chemically mediated, but no studies have considered whether allelopathic compounds are modified by biotic interactions. Here, we show that compounds exuded during Karenia brevis blooms were allelopathic to the cosmopolitan diatom Skeletonema costatum, but that bloom allelopathy varied dramatically among collections and years. We investigated several possible causes of this variability and found that neither bloom density nor concentrations of water-borne brevetoxins correlated with allelopathic potency. However, when we directly tested whether the presence of competing phytoplankton influenced bloom allelopathy, we found that S. costatum reduced the growth-inhibiting effects of bloom exudates, suggesting that S. costatum has a mechanism for undermining K. brevis allelopathy. Additional laboratory experiments indicated that inducible changes to K. brevis allelopathy were restricted to two diatoms among five sensitive phytoplankton species, whereas five other species were constitutively resistant to K. brevis allelopathy. Our results suggest that competitors differ in their responses to phytoplankton allelopathy, with S. costatum exhibiting a previously undescribed method of resistance that may influence community structure and alter bloom dynamics.

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

    OpenAIRE

    Fang eCheng; Zhihui eCheng

    2015-01-01

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

  17. Sorghum allelopathy--from ecosystem to molecule.

    Science.gov (United States)

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

    2013-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Fang eCheng

    2015-11-01

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

  19. 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

  20. Allelopathy--a natural alternative for weed control.

    Science.gov (United States)

    Macías, Francisco A; Molinillo, José M G; Varela, Rosa M; Galindo, Juan C G

    2007-04-01

    Allelopathy studies the interactions among plants, fungi, algae and bacteria with the organisms living in a certain ecosystem, interactions that are mediated by the secondary metabolites produced and exuded into the environment. Consequently, allelopathy is a multidisciplinary science where ecologists, chemists, soil scientists, agronomists, biologists, plant physiologists and molecular biologists offer their skills to give an overall view of the complex interactions occurring in a certain ecosystem. As a result of these studies, applications in weed and pest management are expected in such different fields as development of new agrochemicals, cultural methods, developing of allelopathic crops with increased weed resistance, etc. The present paper will focus on the chemical aspects of allelopathy, pointing out the most recent advances in the chemicals disclosed, their mode of action and their fate in the ecosystem. Also, attention will be paid to achievements in genomics and proteomics, two emerging fields in allelopathy. Rather than being exhaustive, this paper is intended to reflect a critical vision of the current state of allelopathy and to point to future lines of research where in the authors' opinion the main advances and applications could and should be expected.

  1. 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

  2. Potentials and Prospects of Sorghum Allelopathy in Agroecosystems

    Science.gov (United States)

    The promising allelopathic potential of sorghum [Sorghum bicolor L. (Moench)] opens a fruitful area of research to exploit this phenomenon in weed control and regulation of nutrient cycle. The data suggests that sorghum allelopathy can be exploited in different cropping practices such as cover crop,...

  3. [Allelopathy of different plants on wheat, cucumber and radish seedlings].

    Science.gov (United States)

    Shen, Huimin; Guo, Hongru; Huang, Gaobao

    2005-04-01

    By means of bioassay in laboratory and field, this paper studied the allelopathy of 18 kinds of plants in Gansu Province on the seedlings of wheat, cucumber and radish. The results showed that the aqueous extract of the stems and leaves of Artemisia annua, Solanum nigrum and Datura stramonium had the strongest allelopathy on test receptor plants, and their synthetic inhibitory effect (SE) was 47.66%, 32.89% and 26.63%, respectively. The SE of Xanthium sibiricum, Portulaca oleraca, Cephalanoplos segetum, and Chenopodium album was 21.71%, 20.93%, 20.83% and 20.2%, respectively, while Vicia amoena (SE 3.5%), Setaria viridis (SE 2.2%), and Cymamchum chinense (SE 1.97%) had a weaker allelopathy. Chenopodium ambrosioides (SE - 1.03%), Polygonum caespitosum (SE - 1.63%) and Avena fatua (SE 5.33%) had no evident allelopathy, but Artemisia annua affected the seedling height and fresh weight of radish, cucumber, wheat and maize, with the SE being 54.07%, 38.46%, 33.35% and 20.88%, respectively. Artemisia annua had a 44.70% of SE on wheat growth, and thus, had a certain value to develop and use.

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

    Science.gov (United States)

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

    2010-09-01

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

  5. Durum wheat and allelopathy: toward wheat breeding for natural weed management.

    Science.gov (United States)

    Fragasso, Mariagiovanna; Iannucci, Anna; Papa, Roberto

    2013-09-24

    Wheat-derived foodstuffs represent about one-fifth of the calories consumed by humans worldwide. Bread wheat (Triticum aestivum L.) is one of the most important crops throughout the world, and it has been extensively studied for its allelopathic potential. In contrast, for allelopathy in durum wheat (Triticum turgidum ssp. durum), our knowledge is partial and fragmentary. Through highlighting recent advances in using allelopathy as a crop-breeding tool, we provide an overview of allelopathy in Triticum spp., to stimulate further coordinated breeding-oriented studies, to favor allelopathy exploitation for the sustainable cultivation of wheat, and in particular, to achieve improved biological weed control.

  6. Allelopathy: Current Status of Research and the Future of the Discipline: A Commentary

    Science.gov (United States)

    The study of allelopathy as a discipline has a long and varied history. Since Hans Molisch coined the term before World War II, allelopathy research has grown from a trickle of papers before 1970 to a burgeoning subdiscipline of chemical ecology represented by hundreds of papers each year. Yet, al...

  7. [Study on medicinal plant allelopathy and soil sickness based on ecological niche].

    Science.gov (United States)

    Sun, Hao; Huang, Lu-ming; Huang, Lu-qi; Guo, Lan-ping; Zhou, Jie; Lv, Dong-mei; Zeng, Yan

    2008-09-01

    Based on the conception and theory of ecological niche, authors analyzed the cause of the allelopathy and soil sickness of medicinal plants and the relationship between them. Methods to resolve problems in the cultivating medicinal plant was found, that is to construct the ecological niche based on allelopathy theory and avoid the soil sickness.

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

    Science.gov (United States)

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

    2012-06-01

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

  9. Fate of allelopathic substances in space--allelopathy of velvet bean plant and gravity.

    Science.gov (United States)

    Tomita-Yokotani, Kaori; Hashimoto, Hirofumi; Fujii, Yoshiharu; Nakamura, Teruko; Yamashita, Masamichi

    2004-11-01

    Interactions between organisms and species have been long known. It has not been known that the interactive phenomena (allelopathy) may (or may not) differ in space from those on earth. We have studied the gravitational effects on allelopathy by exposing a plant-plant system to pseudo-microgravity, which was generated by a 3D-clinostat. We hypothesized that allelopathy would be modified under altered gravity. L-DOPA (L-3,4-dihydroxyphenylalanine) is known to be the major substance in the allelopathy of velvet bean, released from its root. It has been found that there have been some differences of the allelopathic action of velvet bean plant under pseudo-microgravity. Biosynthesis, release, transport and sensing mechanism associated with allelopathy might be affected by gravity.

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

    Science.gov (United States)

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

    2011-02-01

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

  11. Feedback control in a general almost periodic discrete system of plankton allelopathy.

    Science.gov (United States)

    Yin, Wenshuang

    2014-01-01

    We study the properties of almost periodic solutions for a general discrete system of plankton allelopathy with feedback controls and establish a theorem on the uniformly asymptotic stability of almost periodic solutions.

  12. Barnyard grass-induced rice allelopathy and momilactone B.

    Science.gov (United States)

    Kato-Noguchi, Hisashi

    2011-07-01

    Here, we investigated chemical-mediated interaction between crop and weeds. Allelopathic activity of rice seedlings exhibited 5.3-6.3-fold increases when rice and barnyard grass seedlings were grown together, where there may be the competitive interference between rice and barnyard grass for nutrients. Barnyard grass is one of the most noxious weeds in rice cultivation. The momilactone B concentration in rice seedlings incubated with barnyard grass seedlings was 6.9-fold greater than that in rice seedlings incubated independently. Low nutrient growth conditions also increased allelopathic activity and momilactone B concentrations in rice seedlings. However, the increases in the low nutrient-induced allelopathic activity and momilactone B concentration were much lower than those in barnyard grass-induced allelopathic activity and momilactone B concentration. Root exudates of barnyard grass seedlings increased allelopathic activity and momilactone B concentration in rice seedlings at concentrations greater than 30 mg/L of the root exudates, and increasing the exudate concentration increased the activity and momilactone B concentration. Therefore, barnyard grass-induced allelopathic activity of rice seedlings may be caused not only by nutrient competition between two species, but also by components in barnyard grass root exudates. As momilactone B shows strong allelopathic activities, barnyard grass-induced allelopathic activity of rice may be due to the increased concentration of momilactone B in rice seedlings. The present research suggests that rice may respond to the presence of neighboring barnyard grass by sensing the components in barnyard grass root exudates and increasing allelopathic activity by production of elevated concentration of momilactone B. Thus, rice allelopathy may be one of the inducible defense mechanisms by chemical-mediated plant interaction between rice and barnyard grass, and the induced-allelopathy may provide a competitive advantage for

  13. Genetic evidence for natural product-mediated plant-plant allelopathy in rice (Oryza sativa).

    Science.gov (United States)

    Xu, Meimei; Galhano, Rita; Wiemann, Philipp; Bueno, Emilio; Tiernan, Mollie; Wu, William; Chung, Ill-Min; Gershenzon, Jonathan; Tudzynski, Bettina; Sesma, Ane; Peters, Reuben J

    2012-02-01

    • There is controversy as to whether specific natural products play a role in directly mediating antagonistic plant-plant interactions - that is, allelopathy. If proved to exist, such phenomena would hold considerable promise for agronomic improvement of staple food crops such as rice (Oryza sativa). • However, while substantiated by the presence of phytotoxic compounds at potentially relevant concentrations, demonstrating a direct role for specific natural products in allelopathy has been difficult because of the chemical complexity of root and plant litter exudates. This complexity can be bypassed via selective genetic manipulation to ablate production of putative allelopathic compounds, but such an approach previously has not been applied. • The rice diterpenoid momilactones provide an example of natural products for which correlative biochemical evidence has been obtained for a role in allelopathy. Here, we apply reverse genetics, using knock-outs of the relevant diterpene synthases (copalyl diphosphate synthase 4 (OsCPS4) and kaurene synthase-like 4 (OsKSL4)), to demonstrate that rice momilactones are involved in allelopathy, including suppressing growth of the widespread rice paddy weed, barnyard grass (Echinochloa crus-galli). • Thus, our results not only provide novel genetic evidence for natural product-mediated allelopathy, but also furnish a molecular target for breeding and metabolic engineering of this important crop plant.

  14. Inference of allelopathy is complicated by effects of activated carbon on plant growth.

    Science.gov (United States)

    Lau, Jennifer A; Puliafico, Kenneth P; Kopshever, Joseph A; Steltzer, Heidi; Jarvis, Edward P; Schwarzländer, Mark; Strauss, Sharon Y; Hufbauer, Ruth A

    2008-01-01

    Allelopathy can play an important role in structuring plant communities, but allelopathic effects are often difficult to detect because many methods used to test for allelopathy can be confounded by experimental artifacts. The use of activated carbon, a technique for neutralizing allelopathic compounds, is now employed in tests for allelopathy; however, this technique also could produce large experimental artifacts. In three independent experiments, it was shown that adding activated carbon to potting media affected nutrient availability and plant growth. For most species tested, activated carbon increased plant biomass, even in the absence of the potentially allelopathic agent. The increased growth corresponded to increased plant nitrogen content, likely resulting from greater nitrogen availability. Activated carbon also affected nitrogen and other nutrient concentrations in soil media in the absence of plants. The observed effects of activated carbon on plant growth can confound its use to test for allelopathy. The detection of allelopathy relies on the difference between plant growth in medium with carbon and that in medium without carbon in the presence of the potentially allelopathic competitor; however, this difference may be biased if activated carbon alters soil nutrient availability and plant growth even in the absence of the focal allelopathic agent.

  15. [Allelopathy of decomposing pepper stalk on pepper growth].

    Science.gov (United States)

    Hou, Yongxia; Zhou, Baoli; Wu, Xiaoling; Fu, Yawen; Wang, Yueying

    2006-04-01

    With decomposing pepper stalk as test material, this paper studied its allelopathy on the growth of pepper plants. The results showed that after 60 days of decomposition, the decomposed pepper stalk could decrease the plant height, stem diameter, dry weights of above-and underground biomass, leaf area, and chlorophyll content of pepper plants by 0.0374 - 0.0646, 0.0020 - 0.0097, 0.0050 - 0.0355 and 0.0916 - 0.3584, 0.0016 - 0.0251, and 0.0043 - 0.0242 respectively. These inhibitory effects were enhanced after 120 days of decomposition, but the difference with CK was not significant. The root vigor and its SOD, POD and CAT activities of pepper plants were decreased, while the MDA content and relative conductivity were increased with the increasing concentration of decomposed pepper stalk and with the prolong of treating time. The allelopathic effects of decomposed pepper stalk on the physiological indices of pepper root activity ranged from 0.0163 to 0.6507, which was significantly higher than that of plant growth index.

  16. Models for the directed evolution of bacterial allelopathy: bacteriophage lysins

    Directory of Open Access Journals (Sweden)

    James J. Bull

    2015-04-01

    Full Text Available Microbes produce a variety of compounds that are used to kill or suppress other species. Traditional antibiotics have their origins in these natural products, as do many types of compounds being pursued today in the quest for new antibacterial drugs. When a potential toxin can be encoded by and exported from a species that is not harmed, the opportunity exists to use directed evolution to improve the toxin’s ability to kill other species—allelopathy. In contrast to the typical application of directed evolution, this case requires the co-culture of at least two species or strains, a host that is unharmed by the toxin plus the intended target of the toxin. We develop mathematical and computational models of this directed evolution process. Two contexts are considered, one with the toxin encoded on a plasmid and the other with the toxin encoded in a phage. The plasmid system appears to be more promising than the phage system. Crucial to both designs is the ability to co-culture two species/strains (host and target such that the host is greatly outgrown by the target species except when the target species is killed. The results suggest that, if these initial conditions can be satisfied, directed evolution is feasible for the plasmid-based system. Screening with a plasmid-based system may also enable rapid improvement of a toxin.

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

    Science.gov (United States)

    Slattery, Marc; Lesser, Michael P

    2017-02-18

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

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

    Science.gov (United States)

    Bacellar Mendes, Leonardo Brantes; Vermelho, Alane Beatriz

    2013-10-21

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

  19. Models for the directed evolution of bacterial allelopathy: bacteriophage lysins.

    Science.gov (United States)

    Bull, James J; Crandall, Cameron; Rodriguez, Anna; Krone, Stephen M

    2015-01-01

    Microbes produce a variety of compounds that are used to kill or suppress other species. Traditional antibiotics have their origins in these natural products, as do many types of compounds being pursued today in the quest for new antibacterial drugs. When a potential toxin can be encoded by and exported from a species that is not harmed, the opportunity exists to use directed evolution to improve the toxin's ability to kill other species-allelopathy. In contrast to the typical application of directed evolution, this case requires the co-culture of at least two species or strains, a host that is unharmed by the toxin plus the intended target of the toxin. We develop mathematical and computational models of this directed evolution process. Two contexts are considered, one with the toxin encoded on a plasmid and the other with the toxin encoded in a phage. The plasmid system appears to be more promising than the phage system. Crucial to both designs is the ability to co-culture two species/strains (host and target) such that the host is greatly outgrown by the target species except when the target species is killed. The results suggest that, if these initial conditions can be satisfied, directed evolution is feasible for the plasmid-based system. Screening with a plasmid-based system may also enable rapid improvement of a toxin.

  20. [Allelopathy effects of ferulic acid and coumarin on Microcystis aeruginosa].

    Science.gov (United States)

    Guo, Ya-Li; Fu, Hai-Yan; Huang, Guo-He; Gao, Pan-Feng; Chai, Tian; Yan, Bin; Liao, Huan

    2013-04-01

    The inhibitory effects and allelopathy mechanism of ferulic acid and coumarin on Microcystis aeruginosa were investigated by measuring the D680 value, the content of chlorophyll-a, the electrical conductivity (EC) and superoxide anion radical O*- value. Ferulic acid and coumarin had allelopathic effects on the growth of M. aeruginosa and promoted the physiological metabolism at low concentrations while inhibited the metabolism at high concentrations. Obvious inhibitory effects were observed when the concentration of ferulic acid or coumarin was over 100 mg x L(-1). The average inhibitory rates reached 80.3% and 58.0% after six days when the concentration of ferulic acid or coumarin was 200 mg x L(-1). The content of chlorophyll-a was decreased while the EC value and O2*- concentration were promoted by higher concentrations of ferulic acid or coumarin, suggesting that the growth of algae was inhibited probably by the damage of cell membrane, increase in the content of O2*- and decrease in the content of chlorophyll-a. In addition, seed germination test elucidated that Ferulic acid was safer than Coumarin.

  1. Weeds Cause Losses in Field Crops through Allelopathy

    Directory of Open Access Journals (Sweden)

    Tasawer ABBAS

    2016-03-01

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

  2. Periodic solutions for impulsive delay differential equations in the control model of plankton allelopathy

    Energy Technology Data Exchange (ETDEWEB)

    Jia Junguo [Department of Applied Mathematics, Xi' an Jiaotong University, Xi' an 710049 (China) and Department of Mathematics, Zhengzhou University, Zhengzhou, Henan 450001 (China)]. E-mail: jungjia2@zzu.edu.cn; Wang Miansen [Department of Applied Mathematics, Xi' an Jiaotong University, Xi' an 710049 (China); Li Meili [Department of Applied Mathematics, Xi' an Jiaotong University, Xi' an 710049 (China)

    2007-05-15

    In this paper, a two-dimensional non-autonomous system with impulse that arises in plankton allelopathy involving discrete time delays and periodic environmental factors is studied. By the theory of the coincidence degree we obtain the conditions for the existence of periodic solution of this system.

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

    Science.gov (United States)

    Rasher, Douglas B; Hay, Mark E

    2014-02-22

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

  4. Contribution of momilactone A and B to rice allelopathy.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Hasegawa, Morifumi; Ino, Takeshi; Ota, Katsumi; Kujime, Hiroya

    2010-07-01

    Eight cultivars of rice (Oryza sativa L.) inhibited shoot and root growth of Echinochloa crus-galli when co-cultured with rice seedlings in a bioassay medium. Momilactone A and B were found in the bioassay medium of all rice cultivars, and concentrations of momilactone A and B in the medium were 0.21-1.5 and 0.66-3.8 micromol/L, respectively, indicating that all rice cultivars may secrete momilactone A and B into the medium. Exogenously applied momilactone A and B inhibited the growth of shoots and roots of E. crus-galli at concentrations greater than 30 and 1 micromol/L, respectively. The concentrations required for 50% growth inhibition of E. crus-galli shoots and roots, respectively, were 146 and 91 micromol/L for momilactone A and 6.5 and 6.9 micromol/L for momilactone B. Considering the growth inhibitory activity and concentrations found in the bioassay medium, momilactone A may have caused only 0.8-2.2% of the observed growth inhibition of E. crus-galli roots and shoots by rice. However, momilactone B in the medium was estimated to be able to cause 59-82% of the observed growth inhibition of E. crus-galli roots and shoots by the rice seedlings. In addition, the concentrations of momilactone B in the medium reflected the observed differences in the growth inhibition of E. crus-galli by the eight rice cultivars investigated. This suggests that the allelopathic activity of rice may depend primarily on the secretion level of momilactone B. Therefore, momilactone B may play a very important role in rice allelopathy.

  5. Competition and allelopathy with resource storage: two resources.

    Science.gov (United States)

    Grover, James P; Wang, Feng-Bin

    2014-06-21

    Allelopathy is added to a familiar mathematical model of competition between two species for two essential resources in a chemostat environment. Both species store the resources, and each produces a toxin that induces mortality in the other species. The corresponding model without toxins displays outcomes of competitive exclusion independent of initial conditions, competitive exclusion that depends on initial conditions (bistability), and globally stable coexistence, depending on tradeoffs between competitors in growth requirements and consumption of the resources. Introducing toxins that act only between, and not within species, can destabilize coexistence leading to bistability or other multiple attractors. Invasibility of the missing species into a resident׳s semitrivial equilibrium is related to competitive outcomes. Mutual invasibility is necessary and sufficient for a globally stable coexistence equilibrium, but is not necessary for coexistence at a locally stable equilibrium. Invasibility of one semitrivial equilibrium but not the other is necessary but not sufficient for competitive exclusion independent of initial conditions. Mutual non-invasibility is necessary but not sufficient for bistability. Numerical analysis suggests that when competitors display bistability in the absence of toxin production, increases in the overall magnitude of resource supply cause bistability to arise over a larger range of supply ratios between the two resources. When competitors display coexistence in the absence of toxin production, increases in overall resource supply destabilize coexistence and produce bistability or other configurations of multiple attractors over large ranges of supply ratios. The emergence of multiple attractors at high resource supplies suggests that blooms of harmful algae producing allelopathic toxins could be difficult to predict under such rich conditions.

  6. 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.

  7. Karlodinium veneficum in India: Effect of fixatives on morphology and allelopathy in relation to Skeletonema costatum

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, R.K.; Chitari, R.R.; Anil, A.C.

    CURRENT SCIENCE, VOL. 99, NO. 8, 25 OCTOBER 2010 1112 *For correspondence. (e-mail: acanil@nio.org) Karlodinium veneficum in India: effect of fixatives on morphology and allelopathy in relation to Skeletonema costatum R. K. Naik, R. R. Chitari...-dependence), its relation with nutrient concentra- tion, and the role of predation-induced defensive metabo- lites need to be elucidated in future experiments. 1. Ballantine, D., Two new marine species of Gymnodinium isolated from the Plymouth area. J. Mar...

  8. Separation of allelopathy from resource competition using rice/barnyardgrass mixed-cultures.

    Directory of Open Access Journals (Sweden)

    Hai Bin He

    Full Text Available Plant-plant interference is the combined effect of allelopathy, resource competition, and many other factors. Separating allelopathy from resource competition is almost impossible in natural systems but it is important to evaluate the relative contribution of each of the two mechanisms on plant interference. Research on allelopathy in natural and cultivated plant communities has been hindered in the absence of a reliable method that can separate allelopathic effect from resource competition. In this paper, the interactions between allelopathic rice accession PI312777, non-allelopathic rice accession Lemont and barnyardgrass were explored respectively by using a target (rice-neighbor (barnyardgrass mixed-culture in hydroponic system. The relative competitive intensity (RCI, the relative neighbor effect (RNE and the competitive ratio (CR were used to quantify the intensity of competition between each of the two different potentially allelopathic rice accessions and barnyardgrass. Use of hydroponic culture system enabled us to exclude any uncontrolled factors that might operate in the soil and we were able to separate allelopathy from resource competition between each rice accession and barnyardgrass. The RCI and RNE values showed that the plant-plant interaction was positive (facilitation for PI312777 but that was negative (competition for Lemont and barnyardgrass in rice/barnyardgrass mixed-cultures. The CR values showed that one PI312777 plant was more competitive than 2 barnyardgrass plants. The allelopathic effects of PI312777 were much more intense than the resource competition in rice/barnyardgrass mixed cultures. The reverse was true for Lemont. These results demonstrate that the allelopathic effect of PI312777 was predominant in rice/barnyardgrass mixed-cultures. The most significant result of our study is the discovery of an experimental design, target-neighbor mixed-culture in combination with competition indices, can successfully

  9. Separation of allelopathy from resource competition using rice/barnyardgrass mixed-cultures.

    Science.gov (United States)

    He, Hai Bin; Wang, Hai Bin; Fang, Chang Xun; Lin, Zhi Hua; Yu, Zheng Ming; Lin, Wen Xiong

    2012-01-01

    Plant-plant interference is the combined effect of allelopathy, resource competition, and many other factors. Separating allelopathy from resource competition is almost impossible in natural systems but it is important to evaluate the relative contribution of each of the two mechanisms on plant interference. Research on allelopathy in natural and cultivated plant communities has been hindered in the absence of a reliable method that can separate allelopathic effect from resource competition. In this paper, the interactions between allelopathic rice accession PI312777, non-allelopathic rice accession Lemont and barnyardgrass were explored respectively by using a target (rice)-neighbor (barnyardgrass) mixed-culture in hydroponic system. The relative competitive intensity (RCI), the relative neighbor effect (RNE) and the competitive ratio (CR) were used to quantify the intensity of competition between each of the two different potentially allelopathic rice accessions and barnyardgrass. Use of hydroponic culture system enabled us to exclude any uncontrolled factors that might operate in the soil and we were able to separate allelopathy from resource competition between each rice accession and barnyardgrass. The RCI and RNE values showed that the plant-plant interaction was positive (facilitation) for PI312777 but that was negative (competition) for Lemont and barnyardgrass in rice/barnyardgrass mixed-cultures. The CR values showed that one PI312777 plant was more competitive than 2 barnyardgrass plants. The allelopathic effects of PI312777 were much more intense than the resource competition in rice/barnyardgrass mixed cultures. The reverse was true for Lemont. These results demonstrate that the allelopathic effect of PI312777 was predominant in rice/barnyardgrass mixed-cultures. The most significant result of our study is the discovery of an experimental design, target-neighbor mixed-culture in combination with competition indices, can successfully separate

  10. Effects of ocean acidification on the potency of macroalgal allelopathy to a common coral

    Science.gov (United States)

    Del Monaco, Carlos; Hay, Mark E.; Gartrell, Patrick; Mumby, Peter J.; Diaz-Pulido, Guillermo

    2017-01-01

    Many coral reefs have phase shifted from coral to macroalgal dominance. Ocean acidification (OA) due to elevated CO2 is hypothesised to advantage macroalgae over corals, contributing to these shifts, but the mechanisms affecting coral-macroalgal interactions under OA are unknown. Here, we show that (i) three common macroalgae are more damaging to a common coral when they compete under CO2 concentrations predicted to occur in 2050 and 2100 than under present-day conditions, (ii) that two macroalgae damage corals via allelopathy, and (iii) that one macroalga is allelopathic under conditions of elevated CO2, but not at ambient levels. Lipid-soluble, surface extracts from the macroalga Canistrocarpus (=Dictyota) cervicornis were significantly more damaging to the coral Acropora intermedia growing in the field if these extracts were from thalli grown under elevated vs ambient concentrations of CO2. Extracts from the macroalgae Chlorodesmis fastigiata and Amansia glomerata were not more potent when grown under elevated CO2. Our results demonstrate increasing OA advantages seaweeds over corals, that algal allelopathy can mediate coral-algal interactions, and that OA may enhance the allelopathy of some macroalgae. Other mechanisms also affect coral-macroalgal interactions under OA, and OA further suppresses the resilience of coral reefs suffering blooms of macroalgae. PMID:28145458

  11. Effects of ocean acidification on the potency of macroalgal allelopathy to a common coral

    Science.gov (United States)

    Del Monaco, Carlos; Hay, Mark E.; Gartrell, Patrick; Mumby, Peter J.; Diaz-Pulido, Guillermo

    2017-02-01

    Many coral reefs have phase shifted from coral to macroalgal dominance. Ocean acidification (OA) due to elevated CO2 is hypothesised to advantage macroalgae over corals, contributing to these shifts, but the mechanisms affecting coral-macroalgal interactions under OA are unknown. Here, we show that (i) three common macroalgae are more damaging to a common coral when they compete under CO2 concentrations predicted to occur in 2050 and 2100 than under present-day conditions, (ii) that two macroalgae damage corals via allelopathy, and (iii) that one macroalga is allelopathic under conditions of elevated CO2, but not at ambient levels. Lipid-soluble, surface extracts from the macroalga Canistrocarpus (=Dictyota) cervicornis were significantly more damaging to the coral Acropora intermedia growing in the field if these extracts were from thalli grown under elevated vs ambient concentrations of CO2. Extracts from the macroalgae Chlorodesmis fastigiata and Amansia glomerata were not more potent when grown under elevated CO2. Our results demonstrate increasing OA advantages seaweeds over corals, that algal allelopathy can mediate coral-algal interactions, and that OA may enhance the allelopathy of some macroalgae. Other mechanisms also affect coral-macroalgal interactions under OA, and OA further suppresses the resilience of coral reefs suffering blooms of macroalgae.

  12. Breeding cereal crops for enhanced weed suppression: optimizing allelopathy and competitive ability.

    Science.gov (United States)

    Worthington, Margaret; Reberg-Horton, Chris

    2013-02-01

    Interest in breeding grain crops with improved weed suppressive ability is growing in response to the evolution and rapid expansion of herbicide resistant populations in major weeds of economic importance, environmental concerns, and the unmet needs of organic producers and smallholder farmers without access to herbicides. This review is focused on plant breeding for weed suppression; specifically, field and laboratory screening protocols, genetic studies, and breeding efforts that have been undertaken to improve allelopathy and competition in rice, wheat, and barley. The combined effects of allelopathy and competition determine the weed suppressive potential of a given cultivar, and research groups worldwide have been working to improve both traits simultaneously to achieve maximum gains in weed suppression. Both allelopathy and competitive ability are complex, quantitatively inherited traits that are heavily influenced by environmental factors. Thus, good experimental design and sound breeding procedures are essential to achieve genetic gains. Weed suppressive rice cultivars are now commercially available in the U.S. and China that have resulted from three decades of research. Furthermore, a strong foundation has been laid during the past 10 years for the breeding of weed suppressive wheat and barley cultivars.

  13. Stochastic periodic solution of a non-autonomous toxic-producing phytoplankton allelopathy model with environmental fluctuation

    Science.gov (United States)

    Zhao, Yu; Yuan, Sanling; Zhang, Tonghua

    2017-03-01

    Phytoplankton allelopathy is an ecological phenomenon that concerns the interaction among toxic-producing phytoplankton. Recently, researchers pay great attention to whether the cyclic outbreaks of the harmful algal blooms are related with the allelopathy in a random fluctuating environment. In this paper, we are particularly interested in a non-autonomous toxic-producing phytoplankton allelopathy model with environmental fluctuation. For the model, we first consider the existence of the global positive solution and the boundary periodic solution. Then, by using Khasminskii's method and Lyapunov function, we derive the sufficient conditions for the existence of the nontrivial positive stochastically periodic solution. Our results show that the allelopathic effect plays an important role in the existence of the stochastic periodic solution, for example it can lead to the decrease of the peaks of the cyclic outbreaks of the harmful algal blooms. Numerical simulations are carried out to support our theoretical results.

  14. A Study of Allelopathy of Some Shade Trees to Coffea arabicaL. Seedlings

    Directory of Open Access Journals (Sweden)

    Adi Prawoto

    2006-05-01

    Full Text Available Because of social economic judgment, many coffee planters nowadays grow Cassia spectabilisand in the certain regions used Cinnamomum burmani, Macadamia integrifolia, Tectona grandisand Cassia siameaas shade trees or intercrops. Before being used in large scale, allelopathy study is appropriate to be done because this effect is much more difficult to be overcome than competiton as growing factor. Research on allelopathy of those species had been conducted in glasshouse of Indonesian Coffee and Cocoa Research Institute using Salisbury & Ross method. Leachate of Cassia spectabilis Cinnamomum burmani, Macadamia integrifolia, Tectona grandisand Cassia siamea, pure media (without plant and control (well water were used as treatments. Planting material of Cinnamomum burmani, Macadamia integrifolia, Tectona grandisand Cassia siameawere as seedlings of one year old, whereas C. spectabiliswas 3 months old. Those materials were planted in polybags 20 cm x 30 cm and replicated five times. The media was a mixture of top soil, manure and sand 1 : 1 : 1 (v/v. After those species were maintained for one months and Arabica seedlings for three month old, watering of coffee seedlings then using leachate from shade trees media. Every two days, each seedling was applied with 200 ml. Control was applied with well water. Pure media was used to study the effect of nutrient supply contained in the leachate. The experiment was stopped at seven month old of the coffee seedlings. The result showed that C. spectabilisreleased chemicals which showed allelopathic effect to Arabica coffee, their growth was inhibited 10% to control. The growth decreament from Cassia siameaand D. zibethinustreatment mainly caused by lower mineral content in the leachate and indicated by weak allelopathic. On the other hand M. integrifoliaand C. burmanidid not show allelopathic to Arabica coffee. Thus, based on allelopathy aspect, it can be included that C. spectabilisand C. siamea were not

  15. Dynamics of a Model of Allelopathy and Bacteriocin with a Single Mutation.

    Science.gov (United States)

    Zou, Lan; Chen, Xingwu; Ruan, Shigui; Zhang, Weinian

    2011-02-01

    In this paper we discuss a model of allelopathy and bacteriocin in the chemostat with a wild-type organism and a single mutant. Dynamical properties of this model show the basic competition between two microorganisms. A qualitative analysis about the boundary equilibrium, a state that microorganisms both vanish, is carried out. The existence and uniqueness of the interior equilibrium are proved by a technical reduction to the singularity of a matrix. Its dynamical properties are given by using the index theory of equilibria. We further discuss its bifurcations. Our results are demonstrated by numerical simulations.

  16. Dynamic Behaviors of a General Discrete Nonautonomous System of Plankton Allelopathy with Delays

    Directory of Open Access Journals (Sweden)

    Yaoping Chen

    2008-01-01

    Full Text Available We study the dynamic behaviors of a general discrete nonautonomous system of plankton allelopathy with delays. We first show that under some suitable assumption, the system is permanent. Next, by constructing a suitable Lyapunov functional, we obtain a set of sufficient conditions which guarantee the global attractivity of the two species. After that, by constructing an extinction-type Lyapunov functional, we show that under some suitable assumptions, one species will be driven to extinction. Finally, two examples together with their numerical simulations show the feasibility of the main results.

  17. Relative contributions of allelopathy and competitive traits to the weed suppressive ability of winter wheat lines against Italian ryegrass

    Science.gov (United States)

    Allelopathy and competitive ability have been identified as independent factors contributing to the weed suppressive ability of crop cultivars; however, it is not clear whether these factors have equal influence on weed suppression outcomes of winter wheat (Triticum aestivum L.) lines in the field. ...

  18. Perspectives on allelopathy in mexican traditional agroecosystems: A case study in tlaxcala.

    Science.gov (United States)

    Anaya, A L; Ramos, L; Cruz, R; Hernández, J G; Nava, V

    1987-11-01

    Agroecosystems in Tlaxcala, Mexico, are surrounded by trees and water channels and have a great variety of cultivated and noncultivated plants. The main results of a study carried out on a traditional agroecosystem in Santa Inés, Tlaxcala are presented. Some ecological aspects of polycultures, plant covers (dry leaves ofAlnus firmifolia, Berula erecta, andJuncus sp.), and the allelopathic potential of crops and noncultivated plants (fresh and dry material) were analyzed. The main plants (trees, shrubs, and herbs) present in the agroecosystem were identified. The total number of weeds in plots where plant covers were added was reduced. The number of nodules ofRhizobium phaseoli and the production of bean and squash increased with plant covers. Corn, beans, and squash showed a clear allelopathic effect, as well asChenopodium murale, Tradescantia crassifolia, Melilotus indicus, andAmaranthus hybridus, among other weeds. The contribution of allelopathy in studies of traditional agroecosystems is of great importance for the management of species in space and time. Allelopathy can be the basis of biological control of pests and weeds and of the discovery of new useful substances.

  19. The coevolution of two phytoplankton species on a single resource: allelopathy as a pseudo-mixotrophy.

    Science.gov (United States)

    Roy, Shovonlal

    2009-02-01

    Without the top-down effects and the external/physical forcing, a stable coexistence of two phytoplankton species under a single resource is impossible - a result well known from the principle of competitive exclusion. Here I demonstrate by analysis of a mathematical model that such a stable coexistence in a homogeneous media without any external factor would be possible, at least theoretically, provided (i) one of the two species is toxin producing thereby has an allelopathic effect on the other, and (ii) the allelopathic effect exceeds a critical level. The threshold level of allelopathy required for the coexistence has been derived analytically in terms of the parameters associated with the resource competition and the nutrient recycling. That the extra mortality of a competitor driven by allelopathy of a toxic species gives a positive feed back to the algal growth process through the recycling is explained. And that this positive feed back plays a pivotal role in reducing competition pressures and helping species succession in the two-species model is demonstrated. Based on these specific coexistence results, I introduce and explain theoretically the allelopathic effect of a toxic species as a 'pseudo-mixotrophy'-a mechanism of 'if you cannot beat them or eat them, just kill them by chemical weapons'. The impact of this mechanism of species succession by pseudo-mixotrophy in the form of alleopathy is discussed in the context of current understanding on straight mixotrophy and resource-species relationship among phytoplankton species.

  20. Seaweed allelopathy against coral: surface distribution of a seaweed secondary metabolite by imaging mass spectrometry.

    Science.gov (United States)

    Andras, Tiffany D; Alexander, Troy S; Gahlena, Asiri; Parry, R Mitchell; Fernandez, Facundo M; Kubanek, Julia; Wang, May D; Hay, Mark E

    2012-10-01

    Coral reefs are in global decline, with seaweeds increasing as corals decrease. Although seaweeds inhibit coral growth, recruitment, and survivorship, the mechanism of these interactions is poorly understood. Here, we used field experiments to show that contact with four common seaweeds induces bleaching on natural colonies of Porites rus. Controls in contact with inert, plastic mimics of seaweeds did not bleach, suggesting seaweed effects resulted from allelopathy rather than shading, abrasion, or physical contact. Bioassay-guided fractionation of the hydrophobic extract from the red alga Phacelocarpus neurymenioides revealed a previously characterized antibacterial metabolite, neurymenolide A, as the main allelopathic agent. For allelopathy of lipid-soluble metabolites to be effective, the compounds would need to be deployed on algal surfaces where they could transfer to corals on contact. We used desorption electrospray ionization mass spectrometry (DESI-MS) to visualize and quantify neurymenolide A on the surface of P. neurymenioides, and we found the molecule on all surfaces analyzed, with highest concentrations on basal portions of blades.

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

    Science.gov (United States)

    Tharayil, Nishanth

    2009-07-01

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

  2. Flavonoids: their structure, biosynthesis and role in the rhizosphere, including allelopathy.

    Science.gov (United States)

    Weston, Leslie A; Mathesius, Ulrike

    2013-02-01

    Flavonoids are biologically active low molecular weight secondary metabolites that are produced by plants, with over 10,000 structural variants now reported. Due to their physical and biochemical properties, they interact with many diverse targets in subcellular locations to elicit various activities in microbes, plants, and animals. In plants, flavonoids play important roles in transport of auxin, root and shoot development, pollination, modulation of reactive oxygen species, and signalling of symbiotic bacteria in the legume Rhizobium symbiosis. In addition, they possess antibacterial, antifungal, antiviral, and anticancer activities. In the plant, flavonoids are transported within and between plant tissues and cells, and are specifically released into the rhizosphere by roots where they are involved in plant/plant interactions or allelopathy. Released by root exudation or tissue degradation over time, both aglycones and glycosides of flavonoids are found in soil solutions and root exudates. Although the relative role of flavonoids in allelopathic interference has been less well-characterized than that of some secondary metabolites, we present classic examples of their involvement in autotoxicity and allelopathy. We also describe their activity and fate in the soil rhizosphere in selected examples involving pasture legumes, cereal crops, and ferns. Potential research directions for further elucidation of the specific role of flavonoids in soil rhizosphere interactions are considered.

  3. The Impact of Competition and Allelopathy on the Trade-Off between Plant Defense and Growth in Two Contrasting Tree Species.

    Science.gov (United States)

    Fernandez, Catherine; Monnier, Yogan; Santonja, Mathieu; Gallet, Christiane; Weston, Leslie A; Prévosto, Bernard; Saunier, Amélie; Baldy, Virginie; Bousquet-Mélou, Anne

    2016-01-01

    In contrast to plant-animal interactions, the conceptual framework regarding the impact of secondary metabolites in mediating plant-plant interference is currently less well defined. Here, we address hypotheses about the role of chemically-mediated plant-plant interference (i.e., allelopathy) as a driver of Mediterranean forest dynamics. Growth and defense abilities of a pioneer (Pinus halepensis) and a late-successional (Quercus pubescens) Mediterranean forest species were evaluated under three different plant interference conditions: (i) allelopathy simulated by application of aqueous needle extracts of Pinus, (ii) resource competition created by the physical presence of a neighboring species (Pinus or Quercus), and (iii) a combination of both allelopathy and competition. After 24 months of experimentation in simulated field conditions, Quercus was more affected by plant interference treatments than was Pinus, and a hierarchical response to biotic interference (allelopathy allelopathy + competition) was observed in terms of relative impact on growth and plant defense. Both species modulated their respective metabolic profiles according to plant interference treatment and thus their inherent chemical defense status, resulting in a physiological trade-off between plant growth and production of defense metabolites. For Quercus, an increase in secondary metabolite production and a decrease in plant growth were observed in all treatments. In contrast, this trade-off in Pinus was only observed in competition and allelopathy + competition treatments. Although Pinus and Quercus expressed differential responses when subjected to a single interference condition, either allelopathy or competition, species responses were similar or positively correlated when strong interference conditions (allelopathy + competition) were imposed.

  4. 东北百里香化感作用%Allelopathy of Thymus mandschuricus

    Institute of Scientific and Technical Information of China (English)

    王玲; 马喜娟; 张秀珍

    2012-01-01

    An experiment was conducted to study the allelopathy of Thymus mandschurricus Ronn. on Jive receptor plants, namely Pinus sylvestris var. mongolica, Larix gmelini, Betula platyphylla, Tagetes erecla and Petunia hybrid by the method of biological test. Results showed that stem-leaf and root extracts of T. mandschuricus had some inhibitory effects on seed germination of B. platyphylla and P. hyhrida, and the inhibitory effects weakened with decreasing extract concentration. Lower concentration of extract had a stimulative effect on seed germination of P. sylvestris var. mongolica to a certain degree. Stem-leaf and root extracts of T. mandschuricus had no harmful effect on the seedling growth of T. erecla and P. hybrida. Extract with a volume ratio of 1 : 1 had certain inhibitory effect on seeding growth of P. sylvestris var. mongolica and L gmelini. The allelopathy effect of stem-leaf extract was stronger than that of root extract. Root length of the receptor plants received a stronger allelopathy effect than seedling height.%通过生物测定法研究了东北百里香茎叶和根水浸液对樟子松、兴安落叶松、白桦、万寿菊、矮牵牛的种子萌发及幼苗生长的化感作用.结果表明,东北百里香茎叶和根水浸液对白桦、矮牵牛的种子萌发有一定抑制作用,抑制效应随水浸液母液与水的体积比降低而减弱;母液与水的体积比低的水浸液对樟子松的种子萌发有一定促进作用.东北百里香茎叶和根水浸液对万寿菊和矮牵牛幼苗生长无明显不良影响,V(母液)∶V(水)=1∶1的水浸液对樟子松、兴安落叶松的幼苗生长有一定抑制作用.东北百里香茎叶水浸液对受体植物的化感作用强于根水浸液.受体植物幼苗的根长受到的化感作用强于苗高.

  5. Taraxacum officinale pollen depresses seed set of montane wildflowers through pollen allelopathy

    Directory of Open Access Journals (Sweden)

    Deirdre Loughnan

    2014-08-01

    Full Text Available Plant species that share pollinators can suffer from interspecific pollen deposition. Male reproductive success is inevitably reduced by the loss of pollen to flowers of another species. Female reproductive success can be affected by reduced stigmatic area or, more strongly, through allelopathic effects by which the admixture of some foreign pollen reduces seed or fruit set. We tested for allelopathic effects of Taraxacum officinale (Asteracaeae pollen on the seed set of montane wildflowers Erythronium grandiflorum (Liliaceae and Erysimum capitatum (Brassicaceae, by hand-pollinating plants with pollen mixtures. Taraxacum is a common invasive species, which produces allelopathic chemicals in its root and vegetative tissue, making it a likely candidate for pollen allelopathy. Flowers of both species produced fewer well-developed seeds when pollinated with pollen mixtures containing Taraxacum pollen. The pollen-allelopathic potential of weedy dandelion may add to its ability to disrupt communities that it invades.

  6. The stationary distribution and ergodicity of a stochastic phytoplankton allelopathy model under regime switching

    Science.gov (United States)

    Zhao, Yu; Yuan, Sanling; Zhang, Tonghua

    2016-08-01

    The effect of toxin-producing phytoplankton and environmental stochasticity are interesting problems in marine plankton ecology. In this paper, we develop and analyze a stochastic phytoplankton allelopathy model, which takes both white and colored noises into account. We first prove the existence of the global positive solution of the model. And then by using the stochastic Lyapunov functions, we investigate the positive recurrence and ergodic property of the model, which implies the existence of a stationary distribution of the solution. Moreover, we obtain the mean and variance of the stationary distribution. Our results show that both the two kinds of environmental noises and toxic substances have great impacts on the evolution of the phytoplankton populations. Finally, numerical simulations are carried out to illustrate our theoretical results.

  7. Allelopathy of the invasive plant Bidens frondosa on the seed germination of Geum japonicum var. chinense.

    Science.gov (United States)

    Wang, X F; Hassani, D; Cheng, Z W; Wang, C Y; Wu, J

    2014-12-12

    Five gradient concentrations (0.02, 0.04, 0.06, 0.08, and 0.10 g/mL) of leaching liquors from the roots, stems, and leaves of the invasive plant Bidens frondosa were used as conditioning fluid to examine its influence on seed germination conditions of the native plant Geum japonicum var. chinense in Huangshan. All leaching liquors of organs suppressed the seed germination of Geum japonicum var. chinense and reduced the final germination percentage and rate, and increased the germination inhibition rate, with a bimodal dependence on concentration. The leaching liquor inhibited the seed germination significantly at the concentration of 0.02 g/mL respectively. The seed germination was also inhibited as the concentration reached to 0.04 g/mL and beyond. Hence the allelopathic effects of the organs were significantly enhanced respectively. This phenomenon represented the presence of allelopathy substances in the root, stem and leaf of Bidens frondosa.

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

    Science.gov (United States)

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

    2016-01-01

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

  9. 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

  10. Prymnesium parvum revisited: relationship between allelopathy, ichthyotoxicity, and chemical profiles in 5 strains.

    Science.gov (United States)

    Blossom, Hannah E; Rasmussen, Silas A; Andersen, Nikolaj G; Larsen, Thomas O; Nielsen, Kristian F; Hansen, Per J

    2014-12-01

    Bioassay-guided discovery of ichthyotoxic algal compounds using in vivo fish assays is labor intensive, costly, and highly regulated. Since the mode of action of most known algal-mediated fish-killing toxins is damage to the cell membranes in the gills, various types of cell-based bioassays are often used for bioassay guided purification of new ichthyotoxins. Here we tested the hypothesis that allelopathy is related to ichthyotoxicity and thus that a microalgal bioassay can be used as a proxy for ichthyotoxicity by comparing the toxicity of five strains of Prymnesium parvum toward rainbow trout (Oncorhynchus mykiss, 10 g) and the microalga Teleaulax acuta. No relationship between median effective concentrations (EC50s) on fish and median lethal concentrations (LC50s) on algae was observed in the 5 strains showing that a microalgal bioassay cannot be used as a proxy for ichthyotoxicity. Fish were more sensitive to P. parvum with EC50s ranging from 6×10(3) to 40×10(3) cells ml(-1), compared to the test alga where LC50s ranged from 30×10(3) to nearly non-toxic at 500×10(3) cells ml(-1). In addition, the cellular concentrations of two recently suggested ichthyotoxins produced by P. parvum, the "golden algae toxins", GAT 512 and a novel GAT 510, did not show any relationship to either ichthyotoxicity or allelopathy, and are not the biologically relevant toxins, but are simply lipids found in algal chloroplasts. Finally, we demonstrate that the recently suggested ichthyotoxin, oleamide, could not be detected in any of the five P. parvum strains above the limit of detection, nor was it found in a (13)C-labeled strain. Instead we document that oleamide can easily be extracted from plastic materials, which may have been the source of oleamide reported previously.

  11. 苔藓植物化感作用研究综述%Review on the Study of Allelopathy Effects of Bryophytes

    Institute of Scientific and Technical Information of China (English)

    刘俊华; 王书平; 马海玲

    2014-01-01

    化感作用是自然界广泛存在的一种物种克生现象,对各生态系统类型具有重要影响。苔藓植物广泛分布于陆地生态系统中,已有的苔藓化感作用研究主要为化感作用的生物测定,整体上尚处起步阶段。该文简要阐述了苔藓植物化感研究的基础,介绍了近年来取得的主要进展,并重点就苔藓植物化感作用研究中存在的问题和今后的发展进行了探讨。%Allelopathy refers to the chemical inhibition of one species by another species,with releasing the inhibitory chemicals into the environment where it affects the development and growth of neighboring plants,and the plant allelopathy has an important influence on all ecosystems. Bryophytes are widespread in terrestrial ecosystems,but the researches on plant allelopathy are just beginning,which rest on the bioas-say of allelopathy. This paper introduced the feasibility of bryophytes allelopathy research ,elucidated the progress of research on the bryophytes allelopathy in the past decades,discussed the existing problems and direction in the field of bryophytes allelopathy.

  12. Identification and comparative analysis of microRNAs in barnyardgrass (Echinochloa crus-galli) in response to rice allelopathy.

    Science.gov (United States)

    Fang, Changxun; Li, Yingzhe; Li, Chengxun; Li, Biliang; Ren, Yongjie; Zheng, Haiping; Zeng, Xiaomei; Shen, Lihua; Lin, Wenxiong

    2015-07-01

    Rice allelopathy is a hot topic in the field of allelopathy, and behaviour of donor allelopathic rice has been well documented. However, few study addresses response of receiver barnyardgrass (BYG). We found that expression of miRNAs relevant to plant hormone signal transduction, nucleotide excision repair and the peroxisome proliferator-activated receptor and p53 signalling pathways was enhanced in BYG co-cultured with the allelopathic rice cultivar PI312777, the expression levels of these miRNAs in BYG plants were positively correlated with allelopathic potential of the co-cultured rice varieties. Treatment of BYG plants with rice-produced phenolic acids also increased miRNA expression in BYG, while treatment with rice-produced terpenoids had no obvious effect on miRNA expression. In the hydroponic system, the largest number of Myxococcus sp. was found in the growth medium containing rice with the highest allelopathic potential. The addition of phenolic acids in the hydroponic medium also increased the number of Myxococcus sp. More interestingly, inoculation with Myxococcus xanthus significantly increased miRNA expression in the treated BYG. Jointed treatments of ferulic acid and M. xanthus led to strongest growth inhibition of BYG. The results suggest that there exist involvement of Myxococcus sp. and mediation of miRNA expression in rice allelopathy against BYG.

  13. Prymnesium parvum revisited: Relationship between allelopathy, ichthyotoxicity, and chemical profiles in 5 strains

    Energy Technology Data Exchange (ETDEWEB)

    Blossom, Hannah E., E-mail: hblossom@bio.ku.dk [Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør (Denmark); Rasmussen, Silas A. [Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 221, 2800 Kgs Lyngby (Denmark); Andersen, Nikolaj G. [Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør (Denmark); Larsen, Thomas O.; Nielsen, Kristian F. [Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Building 221, 2800 Kgs Lyngby (Denmark); Hansen, Per J. [Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør (Denmark)

    2014-12-15

    Highlights: • Five strains of P. parvum were tested for toxicity towards rainbow trout and microalgae. • Toxicity towards microalgae was not correlated to toxicity towards fish. • A microalgal bioassay cannot be used as a reliable proxy for ichthyotoxicity. • Concentrations of GATs were low and not correlated to effects on fish or on algae. • P. parvum does not produce oleamide based on {sup 13}C labeling and extraction in glass. - Abstract: Bioassay-guided discovery of ichthyotoxic algal compounds using in vivo fish assays is labor intensive, costly, and highly regulated. Since the mode of action of most known algal-mediated fish-killing toxins is damage to the cell membranes in the gills, various types of cell-based bioassays are often used for bioassay guided purification of new ichthyotoxins. Here we tested the hypothesis that allelopathy is related to ichthyotoxicity and thus that a microalgal bioassay can be used as a proxy for ichthyotoxicity by comparing the toxicity of five strains of Prymnesium parvum toward rainbow trout (Oncorhynchus mykiss, 10 g) and the microalga Teleaulax acuta. No relationship between median effective concentrations (EC{sub 50}s) on fish and median lethal concentrations (LC{sub 50}s) on algae was observed in the 5 strains showing that a microalgal bioassay cannot be used as a proxy for ichthyotoxicity. Fish were more sensitive to P. parvum with EC{sub 50}s ranging from 6 × 10{sup 3} to 40 × 10{sup 3} cells ml{sup −1}, compared to the test alga where LC{sub 50}s ranged from 30 × 10{sup 3} to nearly non-toxic at 500 × 10{sup 3} cells ml{sup −1}. In addition, the cellular concentrations of two recently suggested ichthyotoxins produced by P. parvum, the “golden algae toxins”, GAT 512 and a novel GAT 510, did not show any relationship to either ichthyotoxicity or allelopathy, and are not the biologically relevant toxins, but are simply lipids found in algal chloroplasts. Finally, we demonstrate that the recently

  14. 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.

  15. Effects of selenium hyperaccumulation on plant-plant interactions: evidence for elemental allelopathy?

    Science.gov (United States)

    El Mehdawi, Ali F; Quinn, Colin F; Pilon-Smits, Elizabeth A H

    2011-07-01

    • Few studies have investigated plant-plant interactions involving hyperaccumulator plants. Here, we investigated the effect of selenium (Se) hyperaccumulation on neighboring plants. • Soil and litter Se concentrations were determined around the hyperaccumulators Astragalus bisulcatus and Stanleya pinnata and around the nonhyperaccumulators Medicago sativa and Helianthus pumilus. We also compared surrounding vegetative cover, species composition and Se concentration in two plant species (Artemisia ludoviciana and Symphyotrichum ericoides) growing either close to or far from Se hyperaccumulators. Then, Arabidopsis thaliana germination and growth were compared on soils collected next to the hyperaccumulators and the nonhyperaccumulators. • Soil collected around hyperaccumulators contained more Se (up to 266 mg Se kg(-1) ) than soil collected around nonhyperaccumulators. Vegetative ground cover was 10% lower around Se hyperaccumulators compared with nonhyperaccumulators. The Se concentration was higher in neighboring species A. ludoviciana and S. ericoides when growing close to, compared with far from, Se hyperaccumulators. A. thaliana showed reduced germination and growth, and higher Se accumulation, when grown on soil collected around Se hyperaccumulators compared with soil collected around nonaccumulators. • In conclusion, Se hyperaccumulators may increase the surrounding soil Se concentration (phytoenrichment). The enhanced soil Se contents around hyperaccumulators can impair the growth of Se-sensitive plant species, pointing to a possible role of Se hyperaccumulation in elemental allelopathy.

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

    Science.gov (United States)

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

    2011-10-01

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

  17. Allelopathy as an emergent, exploitable public good in the bloom-forming microalga Prymnesium parvum.

    Science.gov (United States)

    Driscoll, William W; Espinosa, Noelle J; Eldakar, Omar T; Hackett, Jeremiah D

    2013-06-01

    Many microbes cooperatively secrete extracellular products that favorably modify their environment. Consistent with social evolution theory, structured habitats play a role in maintaining these traits in microbial model systems, by localizing the benefits and separating strains that invest in these products from 'cheater' strains that benefit without paying the cost. It is thus surprising that many unicellular, well-mixed microalgal populations invest in extracellular toxins that confer ecological benefits upon the entire population, for example, by eliminating nutrient competitors (allelopathy). Here we test the hypotheses that microalgal exotoxins are (1) exploitable public goods that benefit all cells, regardless of investment, or (2) nonexploitable private goods involved in cell-level functions. We test these hypotheses with high-toxicity (TOX+) and low-toxicity (TOX-) strains of the damaging, mixotrophic microalga Prymnesium parvum and two common competitors: green algae and diatoms. TOX+ actually benefits from dense populations of competing green algae, which can also be prey for P. parvum, yielding a relative fitness advantage over coexisting TOX-. However, with nonprey competitors (diatoms), TOX- increases in frequency over TOX+, despite benefiting from the exclusion of diatoms by TOX+. An evolutionary unstable, ecologically devastating public good may emerge from traits selected at lower levels expressed in novel environments.

  18. Mixed, short rotation culture of red alder and black cottonwood: growth, coppicing, nitrogen fixation, and allelopathy

    Energy Technology Data Exchange (ETDEWEB)

    Heilman, P.; Stettler, R.F.

    1985-01-01

    Alnus rubra seedlings were grown in a 1:1 mixture at a spacing of 1.2 x 1.2 m with 28 Populus clones (25 clones pf P. trichocarpa, 2 of P. deltoides x P. trichocarpa, and one P. deltoides x P. nigra) in a study established in W. Washington in March 1979. Trees were harvested at 4 yr old. At harvest, average heights were: pure Populus, 10.2 m; Populus in the mixed stand 11.0 m; and alder 8.4 m. Most Populus sprouted satisfactorily after harvest (6.6 shoots/plant when pure, 7.6 shoots/plant in the mixture), but alder sprouted poorly (3.6 shoots/plant). Above-ground biomass at harvest was 15.9 t/ha p.a. for the mixture and 16.7 t/ha p.a. for pure Populus, although the mixture had been more productive at 2 yr. Nitrogenase activity (nitrogen fixation as measured by acetylene reduction) of alder declines in the 4th season; competition was the most important factor influencing this decline. Soil N content had no effect on fixation. A pot study showed that ground Populus leaf and litter material inhibited the growth of red alder seedlings, although soil collected from Populus plots had no effect. Results indicated that allelopathy is probably a minor factor under field conditions, at most, and that growing mixed stands may, on balance, be beneficial. 20 references.

  19. Positive periodic solution of a general discrete non-autonomous difference system of plankton allelopathy with delays

    Science.gov (United States)

    Liu, Zhijun; Chen, Lansun

    2006-12-01

    The main purpose of this paper is to investigate a discrete time non-autonomous difference system of plankton allelopathy with delays. By employing continuous theorem proposed by Gains and Mawhin and some new techniques, a set of verifiable sufficient criteria are established for the existence of at least one strictly positive (componentwise) periodic solution, and as an application, we also examine some special case, showing that these conditions are similar to those of continuous differential system. It is also shown that the time delays are harmless for the existence of positive periodic solutions of system.

  20. Seaweed-coral interactions: variance in seaweed allelopathy, coral susceptibility, and potential effects on coral resilience.

    Directory of Open Access Journals (Sweden)

    Roberta M Bonaldo

    Full Text Available Tropical reefs are in global decline with seaweeds commonly replacing corals. Negative associations between macroalgae and corals are well documented, but the mechanisms involved, the dynamics of the interactions, and variance in effects of different macroalgal-coral pairings are poorly investigated. We assessed the frequency, magnitude, and dynamics of macroalgal-coral competition involving allelopathic and non-allelopathic macroalgae on three, spatially grouped pairs of no-take Marine Protected Areas (MPAs and non-MPAs in Fiji. In non-MPAs, biomass of herbivorous fishes was 70-80% lower, macroalgal cover 4-9 fold higher, macroalgal-coral contacts 5-15 fold more frequent and 23-67 fold more extensive (measured as % of colony margin contacted by macroalgae, and coral cover 51-68% lower than in MPAs. Coral contacts with allelopathic macroalgae occurred less frequently than expected by chance across all sites, while contact with non-allelopathic macroalgae tended to occur more frequently than expected. Transplants of allelopathic macroalgae (Chlorodesmis fastigiata and Galaxaura filamentosa against coral edges inflicted damage to Acropora aspera and Pocillopora damicornis more rapidly and extensively than to Porites cylindrica and Porites lobata, which appeared more resistant to these macroalgae. Montipora digitata experienced intermediate damage. Extent of damage from macroalgal contact was independent of coral colony size for each of the 10 macroalgal-coral pairings we established. When natural contacts with Galaxaura filamentosa were removed in the field, recovery was rapid for Porites lobata, but Pocillopora damicornis did not recover and damage continued to expand. As macroalgae increase on overfished tropical reefs, allelopathy could produce feedbacks that suppress coral resilience, prevent coral recovery, and promote the stability of algal beds in habitats previously available to corals.

  1. Allelopathy in a leguminous mangrove plant, Derris indica: protoplast co-culture bioassay and rotenone effect.

    Science.gov (United States)

    Inoue, Aya; Mori, Daisuke; Minagawa, Reiko; Fujii, Yoshiharu; Sasamoto, Hamako

    2015-05-01

    To investigate allelopathic activity of a leguminous mangrove plant, Derris indica, the 'Protoplasts Co-culture Method' for bioassay of allelopathy was developed using suspension culture. A suspension culture was induced from immature seed and sub-cultured in Murashige and Skoog's (MS) basal medium containing 10 μM each of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzyladenine (BA). The protoplasts were isolated using the separate wells method with 2% each of Cellulase RS, Driselase 20 and Macerozyme R10 in 0.4 M mannitol solution. Protoplast cultures of D. indica revealed that high concentrations of cytokinins, BA and thidiazuron, were effective for cell divisions. The co-cultures of D. indica protoplasts with recipient lettuce protoplasts using 96 multi-well culture plates were performed in MS basal medium containing 0.4 M mannitol solution and 1 μM 2,4-D and 0.1 μM BA. The protoplast density of D. indica used in co-culturing varied from 6 x 10(3) - 10(5) / mL. Very strong inhibitory allelopathic effects of D. indica protoplasts on lettuce protoplast growth were found. A similar strong inhibitory allelopathic activity of dried young leaves on lettuce seedling growth was also observed by using the sandwich method. Rotenone, which is a component of Derris root, dissolved in DMSO, was highly inhibitory on the growth of lettuce protoplasts in culture and this could be one of the causes of the strong allelopathic activity of D. indica.

  2. Seaweed-coral interactions: variance in seaweed allelopathy, coral susceptibility, and potential effects on coral resilience.

    Science.gov (United States)

    Bonaldo, Roberta M; Hay, Mark E

    2014-01-01

    Tropical reefs are in global decline with seaweeds commonly replacing corals. Negative associations between macroalgae and corals are well documented, but the mechanisms involved, the dynamics of the interactions, and variance in effects of different macroalgal-coral pairings are poorly investigated. We assessed the frequency, magnitude, and dynamics of macroalgal-coral competition involving allelopathic and non-allelopathic macroalgae on three, spatially grouped pairs of no-take Marine Protected Areas (MPAs) and non-MPAs in Fiji. In non-MPAs, biomass of herbivorous fishes was 70-80% lower, macroalgal cover 4-9 fold higher, macroalgal-coral contacts 5-15 fold more frequent and 23-67 fold more extensive (measured as % of colony margin contacted by macroalgae), and coral cover 51-68% lower than in MPAs. Coral contacts with allelopathic macroalgae occurred less frequently than expected by chance across all sites, while contact with non-allelopathic macroalgae tended to occur more frequently than expected. Transplants of allelopathic macroalgae (Chlorodesmis fastigiata and Galaxaura filamentosa) against coral edges inflicted damage to Acropora aspera and Pocillopora damicornis more rapidly and extensively than to Porites cylindrica and Porites lobata, which appeared more resistant to these macroalgae. Montipora digitata experienced intermediate damage. Extent of damage from macroalgal contact was independent of coral colony size for each of the 10 macroalgal-coral pairings we established. When natural contacts with Galaxaura filamentosa were removed in the field, recovery was rapid for Porites lobata, but Pocillopora damicornis did not recover and damage continued to expand. As macroalgae increase on overfished tropical reefs, allelopathy could produce feedbacks that suppress coral resilience, prevent coral recovery, and promote the stability of algal beds in habitats previously available to corals.

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

    Science.gov (United States)

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

    2006-05-01

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

  4. Allelopathy in saline agricultural land: Vegetation successional changes and patch dynamics.

    Science.gov (United States)

    Mahmood, K; Malik, K A; Sheikh, K H; Lodhi, M A

    1989-02-01

    allelopathy may be a factor in determining growth and distribution of plants in saline or sodic soils.

  5. Study on Allelopathy of Narcissus pseudonarcissus%几种荷兰水仙的化感作用初探

    Institute of Scientific and Technical Information of China (English)

    刘小磊; 马晓红; 史益敏

    2011-01-01

    Four narcissus varieties, Delibes, Dutch Master, Mount Hood, Pinza were used to study allelopathy. The results showed that the allelopathy responses of four narcissus varieties are in the following order :Delibes>Dutch Master>Mount Hood>Pinza. The water extract from Delibes bulb could affect root and shoot elongation of Chinese cabbage, radish, lettuce, tall fescue and ryegrass. Besides, it reduces the chlorophyll content in tall fescue and ryegrass. Alcohol, acetone and methanol were tested as the solvent and their extracts could inhibit development of radish seeds, in which alcohol extract has the most obvious effect, followed by methanol extract and acetone extract.%对“德拉勃”、“荷兰船长”、“头巾”、“滨莎”4个荷兰水仙品种进行了化感作用研究.结果表明荷兰水仙具有化感作用,化感作用强度顺序为:德拉勃>荷兰船长>头巾>滨莎,鳞茎片水提液对白菜、萝卜、生菜、高羊茅、黑麦草种子胚根和胚芽生长均有抑制作用,对发芽期的高羊茅和黑麦草的叶绿素合成产生抑制作用.以乙醇、丙酮、甲醇作为提取剂,鳞茎片乙醇提取液的化感抑制作用最强,甲醇次之,丙酮最弱.

  6. 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.

  7. The Allelopathy of Eucalyptus on Several Crops and Weeds%桉树对几种农作物和杂草的化感作用研究

    Institute of Scientific and Technical Information of China (English)

    田雪晨; 陈贤兴

    2014-01-01

    通过培养皿法和盆栽法对巨桉(Eucalyptus grandis Hill ex Maiden)、邓恩桉(Eucalyptus dunnii Maiden)的浸出溶液的化感作用进行了研究。研究结果表明,其对玉米(Zea mays)、小麦(Triticum aestivum),萝卜(Raphanus sativus)、绿豆(Vigna radiata)四种农作物的发芽指数和发芽率都有不同程度的抑制作用,但对幼苗生长的抑制作用不太明显;同时,还对土壤种子库中的杂草种子萌发有明显的抑制作用。这说明化感作用是这两种桉树的林下很少有其他植物,容易造成水土流失的原因之一。%The wuthors analyzed the allelopathy of the leaching liquor of Eucalyptus grandis Hill ex Maiden and Eucalyptus dunnii Maiden by the culture dish method and pot-culture method. According to the research,it is found that the Allelopathy restrict in a certain degree the pullulation index and pullulation rate of Zea mays, Triticum aestivum,Raphanus sativus and Vigna radiata,while the restriction effect doesn’t evident for the growing of young seeding. Meanwhile,the allelopathy keeps down the sprouting why of weed seeds in soil seed bank. So the allelopathy is one of the reasons that there are few other plants living under these two eucalyptus where mudslide happens frequently.

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

    Directory of Open Access Journals (Sweden)

    Madalin Parepa

    2012-05-01

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

  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.

  10. 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.

  11. 瑞香狼毒化感作用研究%Study on Allelopathy of Stellera chamaejasme

    Institute of Scientific and Technical Information of China (English)

    韩国君; 夏继桥

    2012-01-01

    The extracting solution from Stellera chamaejasme L. Was used to study its effects on seed germination and seedling growth of five plants, Chenopodium album L., Portulaca oleracea L., Leonurus heterophyllus Sweet., Amaranthus hypochondriacus L. And Celosia cristata L.. The results revealed the existance of allelopathy of 5. Chamaejasme L., which had different levels of affection on seed germination when using distinctive extracting solvents such as distilled water, ethanol and acetone. All the three kinds of extracting solution from S. Chamaejasme L. Had significant inhibition effect on the seedling growth of L. Heterophyllus Sweet. There was obvious inhibitive influence on the fresh weight of shoot roots, plumules and seedlings of Chenopodium album L., L. Heterophyllus Sweet and Celosia cristata L., except the slight increase on the radicle growth of Portulaca oleracea L. And seedling growth of Amaranthus hypochondriacus L. By the extracting solvent of distilled water.%研究了瑞香狼毒(Stellera chamaejasme L.)提取液对藜(Chenopodium album L.)、马齿苋(Portulaca oleracea L.)、益母草(Leonurus heterophyllus Sweet.)、籽粒苋(Amaranthus hypochondriacus L.)、鸡冠花(Celosia cristata L.)等5种植物种子萌发和幼苗生长的影响.结果表明,瑞香狼毒化感作用是存在的,并且瑞香狼毒的水、乙醇、丙酮提取液对种子萌发的影响不同.3种瑞香狼毒提取液对益母草幼苗生长的影响强度一直最大,除瑞香狼毒水提取液对马齿苋幼根生长和籽粒苋幼苗生长略有促进外,其他溶剂提取液对其他几种植物苗根、幼芽和幼苗鲜重均有明显抑制作用.

  12. 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.

  13. Alelopatia e homeopatia no manejo da tiririca (Cyperus rotundus Allelopathy and homeopathy in the management of nutsedge (Cyperus rotundus

    Directory of Open Access Journals (Sweden)

    H.R.O. Silveira

    2010-01-01

    weed of difficult control, causing reduction of stand and yield of a wide variety of commercial crops. Due to its aggressiveness, reproduction capacity, high dispersion and rusticity, its control is difficult and costly. The aim of this work was to evaluate alternative methods of nutsedge control based on allelopathy and homeopathy. In the management with allelopathy, aqueous extracts of jack bean (Canavalia ensiformes, black velvet bean (Stizolobium aterrimum, rosemary pepper (Lippia sidoides and lemon grass (Cymbopogon citratus were tested. With homeopathy, the Hahnemannian centesimal scale was used, testing the 3CH, 6CH, 9CH and 12CH dynamizations. Both experiments were conducted in transparent Gerboxes containing washed coarse sand, 1 to 3 mm thick grains, and 10 healthy nutsedge tubers, distributed evenly within the container. After the application of the treatments, the containers were placed in a BOD germination chamber at 25 oC with a 12 hour photoperiod, where they remained for 15 days until the final evaluation. The extract presenting the best nutsedge management was rosemary pepper, which reduced plantlet emergence percentage and vigor, with the extract of this species causing a length reduction in the nutsedge plant higher than that of 2.5 kg ha-1 a.i. of atrazine, the herbicide used for comparison. The homeopathy treatment did not present a significant difference, not exhibiting the expected effect with its nutsedge control dynamizations. The lemon grass, black velvet bean and jack bean extracts did not present allelopathic effects. However the rosemary pepper extract was found to be promising as a nutsedge alternative management, with further studies being necessary to elucidate the chemical principles involved and its true action in the metabolism of the plant.

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

    Institute of Scientific and Technical Information of China (English)

    王广印; 韩世栋; 陈碧华; 杨和连

    2012-01-01

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

  15. 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.

  16. An inverse relationship between allelopathic activity and salt tolerance in suspension cultures of three mangrove species, Sonneratia alba, S. caseolaris and S. ovata: development of a bioassay method for allelopathy, the protoplast co-culture method.

    Science.gov (United States)

    Hasegawa, Ai; Oyanagi, Tomoya; Minagawa, Reiko; Fujii, Yoshiharu; Sasamoto, Hamako

    2014-11-01

    A bioassay method for allelopathy, the 'protoplast co-culture method' was developed to study the relationship between salt tolerance and allelopathy of three mangrove species, Sonneratia alba, S. caseolaris, and S. ovata. Plants of S. alba grow in the seaward-side high salinity region and plants of the latter two species grow in upstream-side regions of a mangrove forest, respectively. Effects of five sea salts (NaCl, KCl, MgCl2, MgSO4 and CaCl2) on the growth of the suspension cells of the latter two species were first investigated by a small-scale method using 24-well culture plates. S. ovata cells showed higher tolerance than S. caseolaris cells to NaCl and other salts, but were not as halophilic as S. alba cells. Protoplasts isolated from suspension cells were co-cultured with lettuce protoplasts in Murashige and Skoog's (MS) basal medium containing 1 μM 2,4-dichlorophenoxyacetic acid, 0.1 μM benzyladenine, 3% sucrose and 0.6-0.8 M osmoticum. S. caseolaris protoplasts had a higher inhibitory effect on lettuce protoplast cell divisions than S. alba protoplasts at any lettuce protoplast density, and the effect of S. ovata was intermediate between the two. These results were similar to those obtained from a different in vitro bioassay method for allelopathy, the 'sandwich method' with dried leaves. The inverse relationship between allelopathic activity and salt tolerance in suspension cells of Sonneratia mangroves is discussed.

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

    Institute of Scientific and Technical Information of China (English)

    李晓娟; 王强; 倪穗; 阮晓; 王永红; 张焕; 王高峰

    2013-01-01

    以种子发芽率和发芽势为种子萌发参数,以胚根、胚芽长度和鲜重变化为幼苗生长参数,研究了栗(Castanea mollissima)叶水提取物对双子叶植物莴苣(Lactuca sativa)、萝卜(Raphanus sativus)、黄瓜(Cucumis sativus),和单子叶植物洋葱(Alliumcepa)、水稻(Oryza sativa)、小麦(Triticum aestivum)的化感作用;比较了美国板栗(Castanea dentata)与栗叶水提取物及经X-5大孔树脂分离获得的11个洗脱组分间的化感作用强弱;利用液相色谱-质谱联用技术结合标准物质的反证实验,解析了美国板栗与栗化感作用最强分离组分的物质结构.研究结果表明,栗叶化感效应强于美国板栗;美国板栗与栗化感作用最强分离组分中(5:5洗脱组分)存在绿原酸、对羟基苯甲酸、原儿茶酸和没食子酸等物质.在利用栗基因恢复美国板栗种群时,有必要考虑美国板栗与栗植物化学生态特性的差异.%Aims Castanea mollissima and C. dentata are typical chestnut species in Asia and North America, respectively. They play important roles in the ecology and economy in their existing forest ecosystems. Chestnut blight has caused catastrophic losses of C. dentata populations since 1904. It is especially important to understand the differences in chemical ecology characteristics between C. dentata and C. mollissima when scientists try to make use of blight resistance of C. dentata to help the recovery of C. mollissima populations in North America. The objective of this research is to compare the allelopathy effect of C. dentata and C. mollissima by leaf water extract bioassay method. Methods Using germination rate and vigor as seed germination parameters and radicle, plumule elongation and fresh weight change of seedling as seedling growth parameters, we studied the effect of water extract of C. mollissima leaves on dicotyledons lettuce, radish and cucumber and monocotyledons onion, rice and wheat. We compared the allelopathic

  18. Allelopathy of Spirogyra communis on Three Submerged Plants%水绵对3种沉水植物的化感作用研究

    Institute of Scientific and Technical Information of China (English)

    马剑敏; 马顷; 苏秀燕; 王程丽; 董文静; 代克岩; 郭萌

    2011-01-01

    The influence of allelopathy of Spirogyra communis was investigated on the chlorophyll content, the activity of some antioxidant enzymes and the relative growth rate of three submerged plants,Potamogeton crispu ,Myriophyllum spicatum and Elodea nuttallii. The results indicated that under co-culture condition,the content of chlorophyll a and chlorophyll b decreased obviously in the three submerged plants,decreasing the largest in E. Nuttallii and the least in M. Spicatum. The activities of POD,CAT and SOD were obviously higher in the three submerged macrophytes than those of the control group. The relative growth rate of the three submerged plants was lower than the control group. E. Nuttallii had the biggest drop of the relative growth rate,while M. Spicatum was the smallest one. On the whole,the influence of S. Communis allelopathy was the greatest on E. Nuttallii and the lowest on M. Spicatum.%研究了水绵(Spirogyra communis)化感作用对菹草(Potamogeton crispu)、狐尾藻(Myriophyllum spicatum)、伊乐藻(Elodea nuttallii)3种沉水植物叶绿素含量、部分抗氧化酶活性和相对生长速率的影响.结果表明:在共培养条件下,处理组3种受试沉水植物的叶绿素a、b含量均明显降低,降幅最大的是伊乐藻,最小的是狐尾藻;3种植物的过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)的活性明显高于对照组(无水绵共培养组);在生物量的增长上,3种沉水植物的相对生长率均低于对照组,其中降幅最大的是伊乐藻,最小的是狐尾藻.总的来看,对水绵的化感胁迫,伊乐藻受到的抑制最大,狐尾藻受到的抑制最小.

  19. Effect of seasonal variation in Sálvia allelopathy potential / Efeito da variação sazonal no potencial alelopático de Sálvia

    Directory of Open Access Journals (Sweden)

    Claudia Tatiana Araujo da Cruz-Silva

    2009-07-01

    Full Text Available The biosynthesis and the accumulation of the chemical composites that have allelopathy characteristics in Salvia officinalis L. (Lamiaceae are resulting from the secondary plant metabolism. The present work had as objective to analyze the allelopathic effects of aqueous extracts of fresh leaves of Sálvia collected during the seasons, obtained by decoction, static infusion and grinding, on the germination and development of seedlings of lettuce (Lactuca sativa L.. The experiment had 20 treatments (concentrations 0; 7.5; 15; 22.5 and 30%. The results had been submitted to the Tukey test, to the level at 5% probability. The appraised variables, germination percentage, the germination speed index (GSI, the growth of shoot and roots and abnormality formation of seedlings did not present a pattern of allelopathy in the different seasons, indicating a possible alteration in the plant metabolism in function of the seasonal variation in the plant ambient.A biossíntese e o acúmulo dos compostos químicos que conferem a característica alelopática em Salvia officinalis L. (Lamiaceae são resultantes do metabolismo secundário do vegetal. O presente trabalho teve como objetivo analisar os efeitos alelopáticos de extratos aquosos de folhas frescas de Sálvia coletadas durante as estações do ano, obtidos por decocção, maceração estática, infusão e trituração sobre a germinação e o desenvolvimento de plântulas de alface (Lactuca sativa L., totalizando 20 tratamentos nas concentrações 0; 7,5; 15; 22,5 e 30%. Os resultados obtidos foram submetidos ao teste de Tukey, ao nível de 5% de probabilidade. As variáveis avaliadas, porcentagem de germinação, índice de velocidade de germinação (IVG, crescimento da parte aérea e das raízes e formação de plântulas anormais não apresentaram um padrão de resposta alelopática nas diferentes estações do ano, indicando possível alteração no metabolismo vegetal em função da varia

  20. 牛尾蒿水浸液对几种植物种子萌发的化感作用%Allelopathy of Artemisia roxburghiana extract to plant seeds germination

    Institute of Scientific and Technical Information of China (English)

    李彦刚; 陈静; 张付斗

    2012-01-01

      Allelopathy is common in higher plants. Appling allelopathy to control farmland weeds is a new research trend. Artemisia species has been commonly used as medicinal plants in traditional Chinese medicine in China for a long time. To explore the application of Artemisia plants in weed control, the water extract of Artemisia roxburghiana Bess. was used to study the allelopathic effects on the germination of lettuce, amaranth, radish, ryegrass, and wild oat seed. The results show that it obviously inhibited the germination of seeds. Allelopathy of Artemisia roxburghiana Bess. has a significant different effects on dicotyledonous and monocotyledonous plants.%  植物化感作用在高等植物中普遍存在,而应用植物化感作用防除农田杂草是目前较为新颖的研究方向。蒿属植物早就是我国中医中常用的药用植物,为探究蒿属植物在农田生态除草方面的应用,选择资源较为丰富的牛尾蒿为研究对象,通过用牛尾蒿水浸提液对莴笋、小米菜、萝卜、黑麦草、野燕麦等植物种子发芽率的试验,表明牛尾蒿对这几种植物有明显的化感作用,并且对双子叶植物和单子叶植物的化感作用有明显的差异

  1. 6种杂草对紫花苜蓿的化感作用%A Study of Allelopathy on Alfalfa with Six Variety of Weeds

    Institute of Scientific and Technical Information of China (English)

    王毅民

    2012-01-01

    This is a study of two alfalfa(Medicago sativa) seeds on seed germination and shoots growing by using water and ethanol extract from six kinds of weeds.The results show that Descuminia Sophia,Ex Prantl,Carduusnutans Linn,Chorispora tenella DC,Capsella bursa-pastoris,Trigonotis peduncularis,and Artemisia frigida Willd.Sp.Pl.all have different degrees of allelopathic effects on alfalfa.Water extracts from CarduusnutansLinn and Chorispora tenella(Pall.) DC,could significantly reduce stem lenghth,dry weight and seed germination rate of Longdong alfalfa and AErGangJin alfalfa.Allelopathy of weeds on AErGangJin alfalfa is greater than that on Longdong alfalfa.%以6种杂草水提液、醇提液对两种紫花苜蓿Medicago sativa品种种子萌发及幼苗生长的影响进行了研究.结果显示:播娘蒿Descuminia sophia(L.)webb.Ex Prantl、飞廉CarduusnutansLinn、离子草Chorisporatenella(Pall.)DC.、荠菜Capsella bursa-pastoris、附地菜Trigonotis peduncularis(Trev.)Benth.和冷蒿Artemis-ia frigida Willd.Sp.Pl.对紫花苜蓿均表现出不同程度的化感作用.飞廉和离子草的水提液显著降低了陇东苜蓿Longdong sativa和阿尔冈金Algonquin幼苗苗长、干质量以及种子的萌发率,播娘蒿的醇提液显著降低了阿尔冈金幼苗苗长、干物质以及种子的萌发率.阿尔冈金品种受杂草的化感作用的影响大于陇东苜蓿品种.

  2. 百合根系分泌物中不同组分的化感作用%Allelopathy of different fractions of lily root exudates

    Institute of Scientific and Technical Information of China (English)

    徐鹏; 程智慧; 梁静; 孟庆玲

    2011-01-01

    【Objective】 The experiment was done to investigate the allelopathy of different components of lily root exudates.【Method】 Lily root exudates were collected with the method of hydroponic cultivation.Petroleum ether,ethyl ether,ethyl acetate,chloroform and methanol were used to isolate lily root exudates by extracting or column chromatography,which was tested by bioassay with radish as the receiver crop.【Result】 All fractions showed inhibitory effect on germination rate,shoot length and shoot fresh mass of radish,but promotion effect on root fresh mass.The fractions of methanol,chloroform,petroleum ether showed inhibitory effect on germination index,germination potentiality and root length,but the fractions of ethyl acetate and ethyl ether showed promotion.On the allelopathic index the fractions of methanol,chloroform,petroleum ether and ethyl ether showed inhibitory effect on seed germination and seedling growth of radish,but the ethyl acetate fraction showed promotion effect.At the same time,the allelopathy order of different fractions was methanol,chloroform,petroleum ether,ethyl acetate and ethyl ether.All fractions led to the increase of MDA content and the activity of IAA oxidase,then the change of protective enzymes SOD and POD activities did not show obvious tendency.【Conclusion】 All fractions of lily root exudates have allelopathy,however the methanol fraction and chloroform fraction have stronger effect.%【目的】明确百合根系分泌物不同组分的化感作用,为揭示百合连作障碍产生的机理奠定理论基础。【方法】通过水培法收集百合根系分泌物,分别用石油醚、乙醚、乙酸乙酯、氯仿萃取及甲醇层析2种方法分离百合根系分泌物,获得不同组分;采用生物测试法,以萝卜为受体检测百合根系分泌物不同组分的化感作用。【结果】各组分对萝卜发芽率、苗高和苗鲜质量均表现出抑制效应,而对根鲜质量均表现出促进效应;甲

  3. Effect of Cinnamomum longepaniculatum allelopathy on the mitosis of Vicia faba root tip cells%宜宾油樟的化感作用对蚕豆根尖细胞有丝分裂的影响

    Institute of Scientific and Technical Information of China (English)

    邓骛远; 罗通; 郑田喜

    2011-01-01

    利用油樟水浸提液作用蚕豆根尖研究了油樟化感作用对蚕豆根尖细胞有丝分裂的影响.结果表明:油樟对蚕豆根尖细胞有丝分裂的化感作用和浸提液浓度、作用时间有密切关系.在实验设计的范围内,随油樟水浸提液浓度的加大,蚕豆根尖细胞有丝分裂指数显著减小,而细胞微核率显著提高;油樟浸提液作用48 h时,对蚕豆根尖细胞有丝分裂的化感作用最强;油樟水浸提液诱导蚕豆根尖细胞产生染色体断片和滞后染色体等多种畸变染色体,并使有丝分裂各时期的分裂相减少.说明油樟化感物质抑制了细胞的有丝分裂,促进微核的产生,从而影响蚕豆根尖的生长和细胞的遗传稳定性.%The effect of Youzhang [Cinnamomum longepaniculatum (Gamble), N.Chan]allelopathy on the mitosis of Vicia faba root tip cells was studied with Youzhang water extracts acting Vicia faba root tips.The result shows the allelopathy has a close relation to the extract concentration and treating time.Within designed range of the experiment, the mitosis index of Vicia faba root tip cells decreases obviously, and the micronucleus frequency rises remarkably along with the increase of Youzhang extract concentrations.When acting time comes to 48 hours, the allelopathy of Youzhang extracts on the mitosis of Vicia faba root tip cells is the strongest.Youzhang water extracts induce a variety of aberrant chromosomes, such as chromosome fregments and delaying chromosomes, and inhibit mitosis different phases.It is implied that Youzhang's allelopthy matter inhibits cell mitosis, and promotes micronucleus generation of cells, and finally affects the growth of Vicia faba root tips and the genetic stability of cells.

  4. Allelopathy of winter cover straws on the initial maize growthAlelopatia de palhadas de coberturas de inverno sobre o crescimento inicial de milho

    Directory of Open Access Journals (Sweden)

    Jaqueline Senen

    2011-07-01

    Full Text Available In agricultural crops is common planting the main crop on the remains of straw harvesting the crop earlier due to no-tillage system. The straw remaining in the soil can exert positive or negative influence on the main crop through the release of organic compounds that carry allelopathy on plants of the subsequent growing. This experiment consisted of mixing and blending of different types of turnip (Brassica rapa L., oats (Avena sativa L., crambe (Crambe abyssinica Hochst. Ex RE Fries, Safflower (Carthamus tinctorius L. and rapeseed (Brassica napus L . var in soil and placed in plastic trays where they planted the seeds of maize. The experimental design was completely randomized design with six treatments and three repetições. As ratings were: emergence, rate of emergence, shoot length, root length, root dry weight, dry weight of shoots. The cover crops canola and safflower showed a positive effect, as crambe, turnips and oats had a negative effect on initial growth of maize seedlings, are not suitable for cover crop to maize sowing.Nas lavouras agrícolas é comum o cultivo da cultura principal sobre os restos de palha da colheita do cultivo anterior em decorrência do sistema de plantio direto. A palhada remanescente no solo pode exercer influência positiva ou negativa sobre a cultura principal pela liberação de compostos orgânicos que exercem alelopatia sobre as plantas da cultura subsequente. Este experimento constou da mistura e homogeneização das palhas de nabo (Brassica rapa L., aveia (Avena sativa L., crambe (Crambe abyssinica Hochst. ex R. E. Fries, cartamo (Carthamus tinctorius L. e canola (Brassica napus L.var no solo, que foi colocado em bandejas plásticas onde semeou-se o milho. O delineamento experimental foi inteiramente casualizados com seis tratamentos e três repetições. As características analizadas foram: emergência, índice de velocidade de emergência, comprimento de parte aérea, comprimento de raiz, massa

  5. 入侵植物马缨丹对4种农作物的化感作用%Allelopathy of Invasive Plant Lantana camara on four Receiver Plants

    Institute of Scientific and Technical Information of China (English)

    卢向荣; 谭忠奇; 林益明; 柴纬明; 周海超

    2013-01-01

    Lantana camara , Verbenaceae family, is one of the invasive alien plants. Previous study about the allelopathy of L. camara mainly focused on exudates from stem and leaf,however,few study analysed the allelopathy of root exudates. At present,with the increasing of L. camara invasion expands scales,the plant has been expanded into farmland gradually. The aims of this study is to determine the allelopathy of different concentrations of water extracts from L. camara leaf and root on the germination and seedling growth of Vigna radiata ,Brassica campestris , Triticum aestivum and Oryza sativa. Different parts and concentrations of water extracts from L. camara had different allelopathic effects on four receiver plants. Except the lowest concentration (2 mg/mL) had slight facilitation effects,other higher concentrations (20,50,100,200 mg/mL)showed significant inhibition effects and the inhibition increased with concentrations. The sensitivity of water extracts from L. camara was different among four tested species,B. campestris was sensitive to allelopathy of L. camara,while O. sativa was not. This study gave theoretical support for improving the competitiveness of crops aroud L. camara,and also provide a scientific foundation for control of current invasions and prevention of future invasions.%马缨丹(Lantana camara)是马鞭草科中一种入侵性极强的外来植物,为了明确马缨丹对入侵地农作物的化感作用,研究了不同浓度马缨丹叶片及根系水浸液对绿豆(Vigna radiata)、油菜(Brassica campestris)、小麦(Triticum aestivum)和水稻(Oryza sativa)种子萌发和幼苗生长的影响.结果表明,马缨丹不同部位及不同浓度水浸液对4种农作物化感效应不同,马缨丹水浸液对4种农作物的种子萌发及幼苗生长具有低质量浓度(2 mg/mL)轻微促进、中高质量浓度(20,50,100和200 mg/mL)较强烈的抑制作用,且随着水浸液浓度的升高其抑制效应不断增强.不同作物对马缨丹

  6. 红花酢浆草提取液对3种草花种子萌发的影响%Allelopathy Effects of Oxalis corymbosa on Seed Germination of Three Herbaceous Flowers

    Institute of Scientific and Technical Information of China (English)

    章玉平; 彭燕燕

    2011-01-01

    In order to study the allelopathy effect on seed germination and seedling growth of the aqueous extracts from leaves and leafstalks of Oxalis corymbosa, probing the invasive mechanism of alien species, the aqueous extracts of O. Corymbosa were used as the test material in this paper. Its purpose was to study the influence of the aqueous extracts of 0. Corymbosa to Tagetes patula, Calendula officinalis and Celosia cristata three herbaceous flowers seed germination and seedling growth. The concentration of the aqueous extracts from leaves and leafstalks of 0. Corymbosa was 0 (CK), 0.625%, 1.25%, 2.5%. The results showed that sensitivity to the aqueous leaf extract of O. Corymbosa differed among the three species. Concentration at 0.625% of the O. Corymbosa aqueous extracts from leaves and leafstalks promoted the germination and seedling growth of Tagetes patula, however, concentration at 1.25%, 2.5% inhibited the germination and seedling growth of Tagetes patula. Concentration at 0.625%, 1.25%, 2.5% of the O. Corymbosa aqueous extracts from leaves and leafstalks inhibited the germination and seedling growth of Calendula officinalis and Celosia cristata, but the inhibition of concentration gradient was not remarkable. The test showed the allelopathy of O. Corymbosa to Tagetes patula was stronger, the allelopathy to Calendula officinalis and Celosia cristata was weaker.%为研究红花酢浆草叶片和叶柄水提取液对3种草花种子萌发的影响,探明外来物种入侵的机制,以红花酢浆草叶片和叶柄的不同浓度水提取液为材料,研究不同浓度(0.625%、1.25%、2.5%)的水提取液浸种对金盏菊、羽状鸡冠花、孔雀草种子萌发的影响.结果表明:不同草花种子对红花酢浆草水提取液的敏感程度不同.0.625%的红花酢浆草水提取液对金盏菊种子萌发具有促进作用,1.25%、2.5%的水提取液对其具有抑制作用.0.625%、1.25%和2.5%的红花酢浆草水提取液对孔雀

  7. Alelopatia de duas espécies de braquiária em sementes de três espécies de estilosantes Allelopathy of two brachiaria species in seeds of three species of stylosanthes

    Directory of Open Access Journals (Sweden)

    Adriana Paula D'Agostini Contreiras Rodrigues

    2012-10-01

    Full Text Available A alelopatia é muito comum em gramíneas como a Brachiaria brizantha e B. decumbens, podendo representar um problema em pastagens consorciadas com Stylosanthes, já que, nessa situação, a perpetuação da leguminosa depende da ressemeadura natural. Apesar da grande quantidade de sementes de estilosantes produzidas anualmente, nessas pastagens consorciadas, observa-se, em campo, pequena quantidade de plantas jovens, o que pode ser atribuído a um possível efeito alelopático da gramínea. Considerando a importância da alelopatia no consórcio de braquiárias com estilosantes, testou-se o potencial alelopático de extratos de Brachiaria brizantha e B. decumbens na germinação de sementes de três espécies de estilosantes. Verificou-se que há efeito alelopático negativo de B. brizantha e B. decumbens na germinação de sementes de Stylosanthes guianensis e somente de B. decumbens na germinação de S. capitata; há efeito alelopático positivo de B. brizantha nas sementes de S. macrocephala; não há efeito alelopático de B. brizantha na germinação de sementes de S. capitata e nem de B. decumbens em S. macrocephala.The allelopathy is very common in grasses such as Brachiaria brizantha and Brachiaria decumbens, could represent a problem in pastures consortium with Stylosantes since, in this situation, the perpetuation of the legume dependent natural reseed. In spite of the great amount of estilosantes seed produced annually in those pastures consortium, it is observed in field, small amount of young plants, which can be attributed to a possible allelopathic effect of the grass. Considering the importance of allelopathy in the consortium of Brachiaria with estilosantes, we tested the allelopathic potential of extracts of B. brizantha and B. decumbens on seed germination of three estilosantes species. It was found that there allelopathic negative effect of B. brizantha and B. decumbens on seed germination of Stylosanthes guianensis and

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

    Institute of Scientific and Technical Information of China (English)

    张海燕; 罗鑫; 张敏

    2015-01-01

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

  9. 麦冬水提液对莴苣等3种植物化感作用的初步研究%Preliminary Study on the Allelopathy of Ophiopogon japonicus Extracts on Lactuca sativa and 2 Other Plants

    Institute of Scientific and Technical Information of China (English)

    徐莹梅; 田胜尼

    2011-01-01

    In this paper the experiments were carried out to study the allelopathy of Ophiopogon japonicus extracts on Lactuca sativa,Cucumis sativus and Raphanus sativus.The results showed that the water extracts of underground and aboveground parts of Ophiopogon japonicus had significant inhibiting effects on the seed germination rate of Cucumis sativus and Raphanus sativus,but no obvious inhibiting effects on that of Lactuca sativa.The extracts also had inhibiting effects on the growth of the main roots of the tested plants,while accelerating the stem growth of Cucumis sativus.%通过麦冬水提液对莴苣、黄瓜、萝卜3种不同植物的化感作用试验研究,结果表明:麦冬地下和地上部分水提液对供试种子黄瓜、萝卜的萌发表现显著的抑制作用,但对莴苣的抑制作用不明显;麦冬水提液对供试植物主根的生长产生抑制作用,而对黄瓜茎的生长表现促进作用。

  10. Allelopathy of two kinds of terraneous plant extracts on Scenedesmus quadricauda%2种陆生植物浸提液对四尾栅藻的化感作用

    Institute of Scientific and Technical Information of China (English)

    郭沛涌; 李庆华; 江中央; 田美燕; 苏东娇

    2011-01-01

    通过合果芋(Syngonium podoph yllum)和榕树(Ficus microcarpa)2种陆生植物不同质量浓度、不同部位浸提液对四尾栅藻(Scenedesmus quadricauda)化感作用的研究,结果表明:合果芋叶和茎浸提液对四尾栅藻表现出促进作用,仅浸提液高质量浓度(50 g· L-1)处理组分别在实验前3d和1d表现出微弱的抑制作用.合果芋叶浸提液对四尾栅藻的促进作用强于茎浸提液.除浸提液30 g· L-1处理组第2d之外,各质量浓度的榕树叶浸提液作用下的四尾栅藻密度均低于对照组,显示了较强的抑制作用.与榕树叶浸提液对四尾栅藻化感作用相似,榕树气生根浸提液对四尾栅藻显示了一定的抑制作用,且随投加浸提液质量浓度的升高对四尾栅藻的抑制作用增强.榕树叶和气生根浸提液对四尾栅藻的EC50.96 h值分别为11.17和47.97 g·L-1,榕树叶浸提液对四尾栅藻的抑制效果好于榕树气生根浸提液.%Allelopathy of two kinds of terraneous plant extracts with different concentrations and different parts on Scenedesmus quadricauda was studied in this paper. The results showed that leaf and stem extracts of Syngonium podo-phyllum had promotive effects on Scenedesmus quadricauda. Only treatment group of high concentration (50 g ? L-1 ) showed slightly inhibitory effect in the 1st day and 3rd day, separately. Besides, the allelopathy of leaf extract was stronger than that of stem extract. In contrast, leaf extract of Ficus microcarpa showed fairly stronger inhibitory effect. Except the treatment group of 30 g ? L-1 in the 2nd day, the densities of Scenedesmus quadricauda in treatment groups of leaf extract with different concentrations were all lower than the controlling group, which had no extract. Similar to leaf extract of Ficus microcarpa , its aerial root extract also showed some inhibitory effect on Scenedesmus quadricauda and the effect became stronger with the rising extract concentration. In addition, the

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

    Institute of Scientific and Technical Information of China (English)

    李青; 石锦安; 刘月婷; 孙莹; 邵小鹏

    2015-01-01

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

  12. 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.

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

    Institute of Scientific and Technical Information of China (English)

    江贵波; 陈少雄; 江晓玲; 杨银娇; 聂耀龙; 蔡玉玲

    2014-01-01

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

  14. 葫芦瓜叶水浸液对蔬菜种子的化感作用%Allelopathy Effects of Water Extract from Leaves of Lagenaria siceraria var. hispida on Vegetable Seeds

    Institute of Scientific and Technical Information of China (English)

    张耀辉; 张丽华; 周娜娜; 陈忠荫; 吕能标

    2012-01-01

    以黄瓜、萝卜和番茄种子为受体材料,采用室内培养皿生物测定方法研究葫芦瓜叶水浸液的化感作用影响,为解决生产实践中的连作障碍问题提供科学依据。结果表明:10 g/L、50 g/L、90 g/L葫芦瓜叶水浸液对黄瓜、萝卜种子萌发率均具有一定的抑制作用,受体材料发芽率均比对照低;对番茄种子萌发率表现为低浓度促进、高浓度抑制;对黄瓜幼苗株高和鲜重都表现抑制作用,对萝卜和番茄幼苗株高和鲜重则表现为,在浓度90 g/L时为抑制作用,在浓度为10 g/L、50 g/L时为促进作用;对黄瓜和萝卜幼苗的根长都表现抑制作用,对番茄幼苗的根长在浓度为10 g/L时表现促进作用,在浓度为50 g/L、90 g/L时表现抑制作用。因此,在蔬菜栽培制度中,葫芦瓜可与番茄和萝卜进行合理的轮作与间套作,但不适宜与黄瓜进行轮作或间套作。%The allelopathy of water extract from the leaves of Lagenaria siceraria var.hispida on the seed germination of cucumber,radish and tomato were investigated by adopting indoor petri dish bioassay in order to provide the scientific basis of continuous cropping barrier solution in production practice.It is found that the water extract at the concentrations of 10,50 and 90 g/L had significant inhibiting effects on the seed germination rates of cucumber and radish.The germination rates of cucumber and radish were lower in the treatments with 10,50 and 90 g water extract/L than in the control with distilled water.The seed germination rate of tomato was increased at lower concentrations,and decreased at higher concentration.The plant height and the fresh weight of cucumber were inhibited at all the concentrations.The plant height and the fresh weight of radish and tomato were inhibited at 90 g/L,and stimulated at 10 g/L and 50 g/L.The water extract had significant inhibiting effects at all the concentrations on the roots of cucumber and radish.The roots of

  15. Elevated Temperature and Allelopathy Impact Coral Recruitment.

    Science.gov (United States)

    Ritson-Williams, Raphael; Ross, Cliff; Paul, Valerie J

    2016-01-01

    As climate change continues to alter seawater temperature and chemistry on a global scale, coral reefs show multiple signs of degradation. One natural process that could facilitate the recovery of reef ecosystems is coral recruitment, which can be influenced by the benthic organisms in a local habitat. We experimentally tested both a global stressor (increased seawater temperature) and a local stressor (exposure to microcolin A, a natural product from a common marine benthic cyanobacterium) to determine how these stressors impacted coral larval sublethal stress, survival and settlement. Larvae of Porites astreoides had the same survival and settlement as the controls after exposure to increased temperature alone, but elevated temperature did cause oxidative stress. When exposed to natural concentrations of microcolin A, larval survival and settlement were significantly reduced. When larvae were exposed to these two stressors sequentially there was no interactive effect; but when exposed to both stressors simultaneously, there was a synergistic reduction in larval survival and an increase in oxidative stress more than in either stressor treatment alone. Increased seawater temperatures made larvae more susceptible to a concurrent local stressor disrupting a key process of coral reef recovery and resilience. These results highlight the importance of understanding how interactive stressors of varying spatial scales can impact coral demographics.

  16. Allelopathy of the invasive plant Alternanthera philoxeroides to radish and lettuce%入侵植物空心莲子草对生菜和萝卜的化感效应

    Institute of Scientific and Technical Information of China (English)

    张志忠; 石秋香; 孙志浩; 蓝茂锋

    2013-01-01

    Alternanthera philoxeroides is a worldwide weed. After invasion of A. philoxeroides,the local ecosystem can be irreversibly damaged and agricultural production seriously affected. Allelopathy is an effective chemical weapon in the invasion process of exotic weeds. With radish {Raphanus salivas) and lettuce (Lactuca sativa) as receptor materials, the allelopathic effect of plant aqueous extract of A. philoxeroides was studied u-sing a Petri dish bioassay. In this process, plant protective enzyme activity was also measured to clarify the allelopathic mechanism. Seed germination rates of lettuce and radish showed significant allelopathic inhibition which gradually increased with an increase of the A. philoxeroides plant aqueous extract concentration. This inhibition in lettuce was significantly greater than in radish. A. philoxeroides plant aqueous extracts caused a general inhibition of the radish and lettuce seedlings growth. Inhibition on radicle growth was significantly greater than on the hypocotyl. At low concentrations (0. 01 g/mL), A. philoxeroides plant aqueous extracts promoted growth of hypocotyls but as the concentration increased, this promotion gradually diminished. Radish and lettuce hypocotyl growth were significantly inhibited at a concentration of 0. 04 g/mL. The degree of inhibition of radicle length and fresh weight gradually increased with increasing concentrations. The radicle growth of radish and lettuce seedlings was almost inhibited at a concentration of 0. 04 g/mL. The degree of inhibition of plant fresh weight in lettuce was more serious than in radish. Changes in protective enzyme activity were more complex. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities increased at low concentrations but as the concentration increased, SOD activity gradually decreased, while POD and CAT activities initially decreased and then increased. Malondialdehyde (MDA) content of radish and lettuce seedlings increased with increased

  17. Allelopathy of aqueous extract from Caragana intermedia root on seven kinds of shrubs and herbs and its chemical component analysis%中间锦鸡儿根水浸提液对7种灌草的化感作用及其化学成分分析

    Institute of Scientific and Technical Information of China (English)

    陈林; 杨新国; 宋乃平; 翟德苹; 赵伟; 刘学东

    2016-01-01

    为了揭示中间锦鸡儿( Caragana intermedia)在人工复合系统以及植被演替中的作用,研究了中间锦鸡儿根水浸提液对荒漠草原7种常见植物(苦豆子、沙打旺、草木樨、披碱草、苏丹草、柠条锦鸡儿和小叶锦鸡儿)的种子萌发和幼苗生长的影响。结果表明:一定质量浓度中间锦鸡儿根水浸提液处理对苦豆子、草木樨、苏丹草、柠条锦鸡儿和小叶锦鸡儿的种子萌发和幼苗生长有抑制作用,而对沙打旺和披碱草起到促进作用;此外,中间锦鸡儿根水浸提液在同一质量浓度处理下对苦豆子、苏丹草和小叶锦鸡儿的种子萌发具有抑制作用,而对其幼苗生长起到一定程度的促进作用。采用气相色谱质谱联用技术分析中间锦鸡儿根水浸提液,共鉴定出21种主要化合物,包括醇、酮、醚、酯、萜类、有机酸、卤代烷以及含氮化合物等8类物质。%Summary Allelopathy played an important role in interspecific relationships of plants . Effects of aqueous extract from Caragana intermedia root on seed germination and seedling growth of plant species in desert steppe were investigated , to reveal the function of C . intermedia in artificial compound system and vegetation succession . Seven common species were selected , including Sophora alopecuroides , Astragalus adsurgens , Melilotus of ficinalis , Elymus dahuricus , Sorghum sudanense , Caragana korshinskii and Caragana microphylla . Laboratory bioassays were conducted , and gas chromatography‐mass spectrometry (GC‐MS) was used to analyze the compounds in the aqueous extract from C . intermedia root . The results showed that allelopathic effects were observed for aqueous extract from C . intermedia root , but showed distinct influences on different species . Seed germination and seedling grow th of five species ( S . alopecuroides , M . of f icinalis , S . sudanense , C . korshinskii and C . microphylla) were

  18. Quantitative Trait Loci Analysis of Allelopathy in Rice

    DEFF Research Database (Denmark)

    Jensen, L B; Courtois, B; Olofsdotter, M

    2008-01-01

    the population phenotype was normally distributed. Two quantitative trait loci (QTLs) were located on chromosomes 4 and 7, explaining 20% of the phenotypic variation. A second relay seeding experiment was set up, this time including charcoal in the perlite. This screening showed that the allelopathic rice...

  19. Seasonality effect on the allelopathy of cerrado species

    Directory of Open Access Journals (Sweden)

    AB Gatti

    Full Text Available The Brazilian cerrado presents strong climate seasonality. During the dry season, plants may be exposed to stressful situations, such as a soil surface water deficit, that stimulate their chemical defenses. However, the seasonality effect on the production of allelopathic compounds of cerrado plant species is poorly understood. In this study, the phytotoxic activities of common native cerrado plants were evaluated during rainy and dry seasons. Crude leaves extracts (10% concentration: weight/volume, with dry leaves and distilled water from eleven species were tested on lettuce and sesame germination. The negative effects on germination percentages, rates and informational entropies of the target species were higher when submitted to plant extracts from the dry season, where the germination rate was the most sensible parameter. The higher sensibility of lettuce and the germination rate parameter showed this difference. Only two exceptions had higher effects for rainy season extracts; one species showed higher negative effects on germination informational entropy of lettuce and another species on the germination rate of sesame. Thus, increases in the allelopathic activity were seen in the majority of the studied cerrado plant species during the dry season. These distinct responses to stressful situations in a complex environment such as the Brazilian cerrado may support the establishment and survival of some species.

  20. Biochar mitigation of allelopathy induced yield loss in continuous maize

    Science.gov (United States)

    Continuous maize yields are limited by the release of phytotoxic compounds as the previous year’s maize residue decomposes. We tested the hypothesis that soil biochar applications could help mitigate maize autotoxicity and the associated yield depression. Eighteen small field plots (23.7 m2) were es...

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

    Science.gov (United States)

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

    2016-09-19

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

  2. Seasonality effect on the allelopathy of cerrado species.

    Science.gov (United States)

    Gatti, A B; Takao, L K; Pereira, V C; Ferreira, A G; Lima, M I S; Gualtieri, S C J

    2014-08-01

    The Brazilian cerrado presents strong climate seasonality. During the dry season, plants may be exposed to stressful situations, such as a soil surface water deficit, that stimulate their chemical defenses. However, the seasonality effect on the production of allelopathic compounds of cerrado plant species is poorly understood. In this study, the phytotoxic activities of common native cerrado plants were evaluated during rainy and dry seasons. Crude leaves extracts (10% concentration: weight/volume, with dry leaves and distilled water) from eleven species were tested on lettuce and sesame germination. The negative effects on germination percentages, rates and informational entropies of the target species were higher when submitted to plant extracts from the dry season, where the germination rate was the most sensible parameter. The higher sensibility of lettuce and the germination rate parameter showed this difference. Only two exceptions had higher effects for rainy season extracts; one species showed higher negative effects on germination informational entropy of lettuce and another species on the germination rate of sesame. Thus, increases in the allelopathic activity were seen in the majority of the studied cerrado plant species during the dry season. These distinct responses to stressful situations in a complex environment such as the Brazilian cerrado may support the establishment and survival of some species.

  3. Allelopathy by extracts of Caatinga species on melon seeds

    Directory of Open Access Journals (Sweden)

    Andreya Kalyana de Oliveira

    2016-04-01

    Full Text Available The melon crop is of great socioeconomic importance in Brazil and some species from the Caatinga biome show allelopathic effects on other species. The aim of this study was to assess leaf and seed extracts of cumaru (Amburana cearensis (Allemao A.C. Sm., the jujube tree (Zizyphus joazeiro Mart., Jucá (Caesalpinia ferrea Mart. Ex. Tul. Var. Ferrea and mulungu (Erythrina velutina Willd. on the emergence of melon seeds (Cucumis melo L.. Leaves and seeds were used to produce extracts for each species at concentrations of a 1%, b 0.5% c 0.25%, d 0.125% and e 0% (control. The experiment was conducted with each extract type and its respective concentrations in a completely randomized design, with four replicates, each of 20 seeds. The percentage emergence and rate index, percentage of abnormal seedlings, seedling dry matter and seedling shoot and root length were assessed. Seed extracts of A. cearensis prevented melon germination, whereas the other extracts had no effect on this variable. Leaf extracts of A. cearensis and leaf and seed extracts of Z. joazeiro, C. ferrea and E. velutina resulted in abnormal melon seedlings. The percentage of abnormal melon seedlings exceeded 30% when treated with C. ferrea seed extract at the highest concentration. Most extracts did not affect seedling dry matter, but E. velutina leaf and seed extract increased the dry matter accumulation of melon seedlings and Z. joazeiro seed extract decreased dry matter accumulation at a concentration of 0.25%. The highest concentrations of mulungu and jucá leaf extracts promoted the shoot growth of melon seedlings. The extract from E. velutina seeds negatively affected root length compared to the control, similar to the effect of C. ferrea and E. velutina leaf extracts at the highest concentrations. Extracts of different organs of Caatinga plants can affect the emergence and characteristics related to seedling growth, depending on the concentration. Most extracts did not affect germination or the emergence rate index, but affected seedling growth.

  4. An allelopathy based model for the Listeria overgrowth phenomenon.

    Science.gov (United States)

    Fgaier, Hedia; Kalmokoff, Martin; Ells, Timothy; Eberl, Hermann J

    2014-01-01

    In a standard procedure of food safety testing, the presence of the pathogenic bacterium Listeria monocytogenes can be masked by non-pathogenic Listeria. This phenomenon of Listeria overgrowth is not well understood. We present a mathematical model for the growth of a mixed population of L. innocua and L. monocytogenes that includes competition for a common resource and allelopathic control of L. monocytogenes by L. innocua when this resource becomes limited, which has been suggested as one potential explanation for the overgrowth phenomenon. The model is tested quantitatively and qualitatively against experimental data in batch experiments. Our results indicate that the phenomenon of masked pathogens can depend on initial numbers of each population present, and on the intensity of the allelopathic effect. Prompted by the results for the batch setup, we also analyze the model in a hypothetical chemostat setup. Our results suggest that it might be possible to operate a continuous growth environment such that the pathogens outcompete the non-pathogenic species, even in cases where they would be overgrown in a batch environment.

  5. Allelopathy of plant species of pharmaceutical importance to cultivated species

    Directory of Open Access Journals (Sweden)

    Álisson Sobrinho Maranho

    2012-11-01

    Full Text Available This study aimed to identify possible allelopathic effects of leaf aqueous extracts of Baccharis dracunculifolia DC., Pilocarpus pennatifolius Lem., Cyperus rotundus L., Morus rubra L., Casearia sylvestris Sw., and Plectranthus barbatus Andr. on the germination and initial growth of Lactuca sativa L., Brassica oleracea L. cv. capitata, B. oleracea L. cv. italica, B. pekinenses L., B. campestris L., Lycopersicum esculentum Miller, and Eruca sativa L. To obtain the aqueous extracts, leaves previously dried at a 1g.10mL-1 concentration were used, diluted in six solutions (10, 30, 50, 70, 90, and 100% and compared to control, distilled water, with five replications of 10 seeds for all vegetable species. The aqueous extracts of all species showed allelopathic potential for germination of seeds, the germination speed index, and the initial growth of shoots and roots of vegetable crops. The aqueous extracts of C. rotundus and P. barbatus promoted lower and higher allelopathic effects, respectively, and the vegetal structure mostly affected by the extracts was the primary root. The results indicate the existence of allelopathic potential in the species tested, so there’s a need for adopting care procedures when cultivating vegetables with them.

  6. Allelopathy in two species of Chenopodium -inhibition of germination and seedling growth of certain weeds

    Directory of Open Access Journals (Sweden)

    Subhash C. Datta

    2014-01-01

    Full Text Available The activity of washed leaf and inflorescence material of Chenopodium ambrosioides and C. murale, decaying leaves and inflorescences, and field soils collected beneath Chenopodium plants were examined in terms of the inhibition of seed germination and seedling growth of five weeds, viz. Abutilon indicum, Cassia sophera var. purpurea, C. tora, Evolvulus numularius and Tephrosia hamiltonii. The allelopathic pattern varied in each of the two test species and this depended on the type of test matter. However, the germination as well as the root and hypocotyl growth of A. indicum and E. nummularius were more hampered by phytotoxins or inhibitors from Chenopodium than were the other weeds. Since the leaf and inflorescence of Chenopodium formed the source of inhibitors, the respective plant-parts from the two species were chemically analysed and the presence of three terpenes (p-cymene, ascaridole and aritazone from C. ambrosioides and an organic acid (oxalic acid from C. murale were implicated in the allelopathic effect.

  7. Leucaena allelopathy on weeds and soybean seed germination / Alelopatia de Leucena sobre soja e plantas invasoras

    Directory of Open Access Journals (Sweden)

    Raquel Leszczynski

    2009-07-01

    Full Text Available With the advance of agriculture, there was consequent rising in environment degradation. Therefore, It is interesting the use of plants which have in their chemical composition substances capable of helping in the control of weeds to minimize the use of pesticides. Hence, the objective of this paper was to evaluate solutions of leucena extract on weeds that are frequent on soybean crop. The treatments were leucena extracts at 0, 20, 40, 60, 80 and 100% at room temperature water and water heated to 80°C. The extracts were obtained by crushing 200g of leucena leaves and mixing them with one liter of distilled water with the help of a blender. Seeds were kept in B.O.D. at a temperature of 25°C, with a photoperiod of 12 hours of light. Evaluations were done on a daily basis, from the first to the last day of the experiment, varying according to the species. Results show a negative interference of the extracts, both hot and cold, in the root length of Ipomoea grandifolia, in the percentage of germination and in the root length of Arrowleaf sida and Hair beggarticks. There was no negative interference in the analyzed parameters for soybean seeds. Thus, the results indicate allelopatic potential of Leucaena leuucocephala as an alternative for the management of weeds without interfering on the development of the soybean crop.Com o desenvolvimento da agricultura surgiram os conseqüentes aumentos na degradação ambiental. Assim, estuda-se a utilização de plantas que possuam em sua composição química substâncias capazes de auxiliar no controle de plantas invasoras, amenizando o uso de agrotóxicos. Desta forma, o objetivo do trabalho foi avaliar soluções de extratos de leucena sobre plantas invasoras que freqüentemente ocorrem na cultura da soja. Foram utilizados como tratamentos os seguintes extratos de leucena nas proporções de: 0, 20, 40, 60, 80 e 100% com água à temperatura ambiente e com água aquecida à 80°C. Os extratos foram obtidos triturando-se 200 g de folhas de leucena em um litro de água destilada, com auxílio de um liquidificador. As sementes foram mantidas em B.O.D. à temperatura de 25°C, com fotoperíodo de 12 horas de luz. As avaliações foram diárias, do primeiro ao último dia de experimento, este variando conforme a espécie. Os resultados demonstraram interferência negativa dos extratos, tanto quente quanto frio, no comprimento de raiz de corda de viola, na porcentagem de germinação e no comprimento de raiz de guanxuma e picão-preto. Não foram constatadas interferências negativas nos parâmetros analisados para as sementes de soja. Sendo assim, os resultados obtidos indicam potencial alelopático da espécie Leucaena leuucocephala como alternativa de manejo de plantas invasoras sem interferir no desenvolvimento da cultura da soja.

  8. The allelopathy of Flaveria bidentis (L.) Kuntze, an invasive weed species

    Institute of Scientific and Technical Information of China (English)

    Jiao XU; Wenehao XU; Yajun YANG; Bu TAO; Jinlin ZHANG

    2008-01-01

    To identify the allelopathic effect of Flaveria bidentis (L.) Kuntze (F, bMenti) on other plants, the effects of different extracts from F. bidentis on the growth of sev-eral plants were studied by bioassay. Results showed that the water extracts inhibited the growth of corn (Zea mays L.), wheat (Triticum aestivum L.), cotton (Gassypium Hirsutum L.), soybean (Glycine hispida L.), peanut (Arachi shypogaea L.), rice (Oryza sativa L.), crabgrass (Digitaria sanguinalis L.) and rigweed (Amaranthus retroflexus L.), with the most reactive indexes found in root and stem of cotton at -0.85 and -0.88, respectively, at a concentration growth of rice. In addition, the reactive indexes of the extracts of petroleum ether chloroform, ethyl acetate, acet and alcohol were higher than that of the water extracts, and that of the acet extracts was the highest. The melting point of the refined acetone extract ranged from 192.5℃ to 193.5℃, and its maximum absorbing wavelength was 220 nm. This extract was found to be herbicide-active and played an inhibitory role in the growth of crabgrass and

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

    Science.gov (United States)

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

    2003-01-01

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

  10. Multiple periodic solutions for a discrete time model of plankton allelopathy

    OpenAIRE

    Zhang Jianbao; Fang Hui

    2006-01-01

    We study a discrete time model of the growth of two species of plankton with competitive and allelopathic effects on each other N1(k+1) = N1(k)exp{r1(k)-a11(k)N1(k)-a12(k)N2(k)-b1(k)N1(k)N2(k)}, N2(k+1) = N2(k)exp{r2(k)-a21(k)N2(k)-b2(k)N1(k)N1(k)N2(k)}. A set of sufficient conditions is obtained for the existence of multiple positive periodic solutions for this model. The approach is based on Mawhin's continuation theorem of coincidence degree theory as well as some a priori estimates. Some...

  11. Alelopatia de cultivos de cobertura vegetal sobre plantas infestantes = Allelopathy of cover crop on weed plants

    Directory of Open Access Journals (Sweden)

    Luciene Kazue Tokura

    2006-07-01

    Full Text Available O presente trabalho avaliou o potencial alelopático de cultivos de cobertura vegetal de trigo, aveia preta, milheto, nabo forrageiro e colza sobre o desenvolvimento de plantas infestantes e verificou qual das coberturas vegetais exerce maior controle sobre as mesmas. Os cultivos de cobertura vegetal foram implantados sob preparo convencional (uma aração e uma gradagem no Núcleo Experimental de Engenharia Agrícola (NEEA, da Universidade Estadual do Oeste do Paraná (Unioeste, Cascavel, Estado do Paraná. Mensalmente, realizou-se o acompanhamento e identificação das plantas infestantes emersas nas áreas de cobertura vegetal no período de agosto de 2000 a agosto de 2001. Os resultados obtidos permitiram concluir que das espécies encontradas, o capim marmelada foi o que apresentou maior potencial alelopático e a erva-de-santa-maria o menor. As coberturasvegetais que apresentaram melhor controle do total de plantas infestantes presentes na área experimental, incluindo àquelas com reconhecido potencial alelopático, foram aveia preta, colza, nabo forrageiro e milheto.This work evaluated the cover crop allelopathic potential of wheat, black oat, pearl millet, turnip and rape on the development of weed plants. It also verified which cover crop has larger control on the weed plants. The cover crop was implanted under conventional tillage (one disk plowing plus one disk harrowing in the Experimental Nucleus of Agricultural Engineering (NEEA, of the State University of the West of Paraná (Unioeste, Cascavel, Paraná State. Monthly (from August 2000 to August 2001, weed plants identification in the cover crop area was made. Results showed that from the found species, the alexander grass was the one that presented larger allelopathic potential, and, the mexican-tea was the one that presented smaller control. The vegetable coverings that presented larger control of the total of weed plants in the experimental area, including those with recognized allelopathic potential, was black oat, rape, turnip and pearl millet.

  12. 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.

  13. 藨草化感作用的研究%Study on allelopathy of Scirpus triquetet

    Institute of Scientific and Technical Information of China (English)

    陈遂中; 谢慧琴; 王春娟; 吴晓峰

    2010-01-01

    采用室内生测和生理实验的方法,以小麦Triticum aestivum、萝卜Raphanus sativus、黄瓜Cucumis satirus作物为研究对象,探讨藨草Scirpus triquetet 的化感作用和作用机理.结果表明:藨草不同有机溶剂萃取液对3种作物均有化感效应,随着萃取组分极性的增加,对3种作物种子萌发的抑制效应逐渐增强;同时,不同萃取组分对作物幼苗生长均有不同程度的抑制,降低了根系活力,不同组分对作物幼苗根系的抑制作用表现为丙二醛(MDA)含量增加,过氧化物酶(POD)酶活性升高,过氧化氢酶(CAT)酶活性降低,叶绿素含量降低.表明藨草对小麦、萝卜、黄瓜均有化感作用.

  14. The Case Against (-)-Catechin Involvement in Allelopathy in Centaurea stoebe (spotted knapweed)

    Science.gov (United States)

    Proving allelopathic chemical interference is a daunting endeavor, in that production and movement of a phytotoxin from a donor plant to a receiving plant must be demonstrated in the substrate in which the plants grow, which is usually a complex soil matrix. The soil levels or soil flux levels of th...

  15. Developments in rice allelopathy: Searching for the balance between allelopathic activity, agronomic viability and commercial acceptability

    Science.gov (United States)

    Sustainable weed control is an ongoing challenge in rice production. Indica rice lines that suppress troublesome C4 grass weeds such as Echinochloa crus-galli and Leptochloa fusca ssp. fascicularis have been evaluated extensively in Arkansas. Earlier findings suggested that suppression likely incl...

  16. Benzoxazinoids in rye allelopathy - from discovery to application in sustainable weed control and organic farming.

    Science.gov (United States)

    Schulz, Margot; Marocco, Adriano; Tabaglio, Vincenzo; Macias, Francisco A; Molinillo, Jose M G

    2013-02-01

    The allelopathic potency of rye (Secale cereale L.) is due mainly to the presence of phytotoxic benzoxazinones-compounds whose biosynthesis is developmentally regulated, with the highest accumulation in young tissue and a dependency on cultivar and environmental influences. Benzoxazinones can be released from residues of greenhouse-grown rye at levels between 12 and 20 kg/ha, with lower amounts exuded by living plants. In soil, benzoxazinones are subject to a cascade of transformation reactions, and levels in the range 0.5-5 kg/ha have been reported. Starting with the accumulation of less toxic benzoxazolinones, the transformation reactions in soil primarily lead to the production of phenoxazinones, acetamides, and malonamic acids. These reactions are associated with microbial activity in the soil. In addition to benzoxazinones, benzoxazolin-2(3H)-one (BOA) has been investigated for phytotoxic effects in weeds and crops. Exposure to BOA affects transcriptome, proteome, and metabolome patterns of the seedlings, inhibits germination and growth, and can induce death of sensitive species. Differences in the sensitivity of cultivars and ecotypes are due to different species-dependent strategies that have evolved to cope with BOA. These strategies include the rapid activation of detoxification reactions and extrusion of detoxified compounds. In contrast to sensitive ecotypes, tolerant ecotypes are less affected by exposure to BOA. Like the original compounds BOA and MBOA, all exuded detoxification products are converted to phenoxazinones, which can be degraded by several specialized fungi via the Fenton reaction. Because of their selectivity, specific activity, and presumably limited persistence in the soil, benzoxazinoids or rye residues are suitable means for weed control. In fact, rye is one of the best cool season cover crops and widely used because of its excellent weed suppressive potential. Breeding of benzoxazinoid resistant crops and of rye with high benzoxazinoid contents, as well as a better understanding of the soil persistence of phenoxazinones, of the weed resistance against benzoxazinoids, and of how allelopathic interactions are influenced by cultural practices, would provide the means to include allelopathic rye varieties in organic cropping systems for weed control.

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

    Science.gov (United States)

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

    2011-10-24

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

  18. 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 fern.

  19. Seaweed allelopathy to corals: are active compounds on, or in, seaweeds?

    Science.gov (United States)

    Longo, G. O.; Hay, M. E.

    2017-03-01

    Numerous seaweeds produce secondary metabolites that are allelopathic to corals. To date, most of the compounds identified in this interaction are lipid-soluble instead of water-soluble. Thus, understanding whether these compounds are stored internally where they would not contact corals, or occur on external surfaces where they could be transferred to corals, is critical to understanding seaweed-coral interactions and to informing realistic experiments on chemically mediated interactions. We conducted field experiments assessing the effects of lipid-soluble extracts from macroalgal surfaces alone versus total lipid-soluble extracts from both internal and external tissues on the coral Pocillopora verrucosa. Extracts of the red algae Amansia rhodantha and Asparagopsis taxiformis, the green alga Chlorodesmis fastigiata, and the brown alga Dictyota bartayresiana suppressed coral photochemical efficiency; in these bioactive species, the total lipid-soluble extracts were not more potent than surface-only extracts despite the concentration of total extracts being many times greater than surface-only extracts. This suggests that previous assays with total extracts may be ecologically meaningful, but also that future assays should be conducted with the simpler, less concentrated, and more ecologically relevant surface extracts. Allelopathic effects of As. taxiformis and C. fastigiata were significantly greater than the effect of D. bartayresiana, with effects of Am. rhodantha intermediate between these groups. Neither surface-only nor total lipid-soluble extracts of the seaweed Turbinaria ornata were allelopathic, and its lack of potency differed significantly from all other species. Our results suggest that lipid-soluble, allelopathic compounds are usually deployed on seaweed surfaces where they can be effective in surface-mediated interactions against other species.

  20. Involvement of allelopathy in the formation of monospecific colonies of ferns.

    Science.gov (United States)

    Kato-Noguchi, Hisashi

    2015-05-01

    Some fern species often dominate plant communities by forming large monospecific colonies. However, the potential mechanism for this domination of the ferns remains obscure. Many plants secrete a wide range of compounds into the rhizosphere and change the chemical and physical properties of the rhizosphere soil. Through the secretion of compounds, such as allelopathic substances, plants inhibit the germination and growth of neighboring plants to compete more effectively for the resources. Ferns contain a variety of secondary metabolites and some of those compounds are released from the ferns into the rhizosphere soil, either as exudates from living ferns or by decomposition of fern residues in sufficient quantities to affect the germination and growth of neighboring plants as allelopathic substances. Therefore, allelopathic chemical interaction of the ferns with neighboring plants may play an important role in the formation of the monospecific colonies of the ferns.

  1. Herbivore exclusion drives the evolution of plant competitiveness via increased allelopathy.

    Science.gov (United States)

    Uesugi, Akane; Kessler, André

    2013-05-01

    The 'Evolution of Increased Competitive Ability (EICA)' hypothesis predicts the evolution of plant invasiveness in introduced ranges when plants escape from their natural enemies. So far, the EICA hypothesis has been tested by comparing plant vigor from native and invasive populations, but these studies are confounded by among-population differences in additional environmental factors and/or founder effects. We tested the major prediction of EICA by comparing the competitive ability (CA) of Solidago altissima plants originating from artificial selection plots in which we manipulated directly the exposure to above-ground herbivores. In a common garden experiment, we found an increase in inter-specific, but not intra-specific, CA in clones from herbivore exclusion plots relative to control plots. The evolutionary increase in inter-specific CA coincided with the increased production of polyacetylenes, whose major constituent was allelopathic against a heterospecific competitor, Poa pratensis, but not against conspecifics. Our results provide direct evidence that release from herbivory alone can lead to an evolutionary increase in inter-specific CA, which is likely to be mediated by the increased production of allelopathic compounds in S. altissima.

  2. Existence of almost periodic solution of a model of phytoplankton allelopathy with delay

    Science.gov (United States)

    Abbas, Syed; Mahto, Lakshman

    2012-09-01

    In this paper we discuss a non-autonomous two species competitive allelopathic phytoplankton model in which both species are producing chemical which stimulate the growth of each other. We have studied the existence and uniqueness of an almost periodic solution for the concerned model system. Sufficient conditions are derived for the existence of a unique almost periodic solution.

  3. Impact of submerged macrophytes including charophytes on phyto- and zooplankton communities: allelopathy versus other mechanisms

    NARCIS (Netherlands)

    Van Donk, E.; Van de Bund, W.J.

    2002-01-01

    Submerged macrophytes are crucial for the stabilization of the clear water state in shallow, mesotrophic and eutrophic lakes. Especially, charophytes often play an important role because they are typically rapid colonizers and because charophyte meadows are believed to have a particularly strong pos

  4. Contribution of a phytotoxic compound to the allelopathy of Ginkgo biloba.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Takeshita, Sayaka

    2013-11-01

    Ginkgo (Ginkgo biloba L.) has not changed over 121 million years. There may be unknown special strategy for the survival. Gingko litter inhibited the growth of weed species ryegrass (Lolium multiflorum L.). The inhibition was greater with the litter of the close position than that of the far position from the gingko tree. A phytotoxic substance, 2-hydroxy-6-(10-hydroxypentadec-11-enyl)benzoic acid (HHPEBA) was isolated in the litter. HHPEBA concentration was greater in the litter of the close position than that of the far position from the tree. HHPEBA inhibited the ryegrass growth at concentrations greater than 3 μM. HHPEBA was estimated to be able to cause 47-62% of the observed growth inhibition of ryegrass by the gingko litter. Therefore, HHPEBA may contribute to the inhibitory effect caused by ginkgo litter and may provide a competitive advantage for gingko to survive through the growth inhibition of the neighboring plants.

  5. Dynamic behaviors of a delay differential equation model of plankton allelopathy

    Science.gov (United States)

    Chen, Fengde; Li, Zhong; Chen, Xiaoxing; Laitochova, Jitka

    2007-09-01

    In this paper, we consider a modified delay differential equation model of the growth of n-species of plankton having competitive and allelopathic effects on each other. We first obtain the sufficient conditions which guarantee the permanence of the system. As a corollary, for periodic case, we obtain a set of delay-dependent condition which ensures the existence of at least one positive periodic solution of the system. After that, by means of a suitable Lyapunov functional, sufficient conditions are derived for the global attractivity of the system. For the two-dimensional case, under some suitable assumptions, we prove that one of the components will be driven to extinction while the other will stabilize at a certain solution of a logistic equation. Examples show the feasibility of the main results.

  6. Macrophyte-phytoplankton interactions: the relative importance of allelopathy versus other factors

    NARCIS (Netherlands)

    Mulderij, G.; Nes, van E.H.; Donk, van E.

    2007-01-01

    Submerged aquatic macrophytes are important in shallow aquatic ecosystems because they stabilize the macrophyte-dominated state by increasing water transparency in various ways. One of these is the excretion of allelopathic substances inhibitory to phytoplankton, but it is still controversial whethe

  7. Changes in rice allelopathy and rhizosphere microflora by inhibiting rice phenylalanine ammonia-lyase gene expression.

    Science.gov (United States)

    Fang, Changxun; Zhuang, Yuee; Xu, Tiecheng; Li, Yingzhe; Li, Yue; Lin, Wenxiong

    2013-02-01

    Gene expression of phenylalanine ammonia-lyase (PAL) in allelopathic rice PI312777 was inhibited by RNA interference (RNAi). Transgenic rice showed lower levels of PAL gene expression and PAL activity than wild type rice (WT). The concentrations of phenolic compounds were lower in the root tissues and root exudates of transgenic rice than in those of wild type plants. When barndyardgrass (BYG) was used as the receiver plant, the allelopathic potential of transgenic rice was reduced. The sizes of the bacterial and fungal populations in rice rhizospheric soil at the 3-, 5-, and 7-leaf stages were estimated by using quantitative PCR (qPCR), which showed a decrease in both populations at all stages of leaf development analyzed. However, PI312777 had a larger microbial population than transgenic rice. In addition, in T-RFLP studies, 14 different groups of bacteria were detected in WT and only 6 were detected in transgenic rice. This indicates that there was less rhizospheric bacterial diversity associated with transgenic rice than with WT. These findings collectively suggest that PAL functions as a positive regulator of rice allelopathic potential.

  8. Macrophyte-phytoplankton interactions: the relative importance of allelopathy versus other factors

    NARCIS (Netherlands)

    Mulderij, G.; van Nes, E.H.; Van Donk, E.

    2007-01-01

    Abstract Submerged aquatic macrophytes are important in shallow aquatic ecosystems because they stabilize the macrophyte-dominated state by increasing water transparency in various ways. One of these is the excretion of allelopathic substances inhibitory to phytoplankton, but it is still controversi

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

    Science.gov (United States)

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

    2003-01-01

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

  10. 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...

  11. Allelopathy of Coriander on Hot Pepper%芫荽对辣椒化感效应的研究

    Institute of Scientific and Technical Information of China (English)

    何建文; 耿广东

    2007-01-01

    以芫荽地上部和根部为试材,研究其不同浓度的水提液对辣椒种子发芽和幼苗生理特性的影响.结果表明,芫荽水提液对辣椒种子发芽表现出一定的抑制作用,且这种作用随水提液浓度的增加而加大;芫荽水提液可使辣椒幼苗的丙二醛含量增加,随着水提液浓度的增加,根系活力先增加后降低,地上部和根部水提液的化感效应相似.

  12. Allelopathy of Camelina sativa Boiss. (Brassicaceae) on germination and early development of Bidens pilosa (L.) and Glycine max (L.) Merr

    OpenAIRE

    Jéssica da Silva; Andréa Maria Teixeira Fortes; Fernanda Melo Gomes; Tassiane Terezinha Pinto; Thaliny Bonamigo; Nayara Parisoto Boiago

    2011-01-01

    This study evaluated the possible presence of allelopathic potential in camelina, as well as its effect on germination and early growth of soybean seedlings and beggarticks, in order, to verify the possibility of cultivating it with soybeans in a culture rotation system and its use as a herbicide. The experiments were carried out at the Laboratory of Plant Physiology of Universidade Estadual do Oeste do Paraná, Cascavel, Paraná, Brazil. The design was completely randomized and the evaluations...

  13. Allelopathy of Camelina sativa Boiss. (Brassicaceae on germination and early development of Bidens pilosa (L. and Glycine max (L. Merr

    Directory of Open Access Journals (Sweden)

    Jéssica da Silva

    2011-12-01

    Full Text Available This study evaluated the possible presence of allelopathic potential in camelina, as well as its effect on germination and early growth of soybean seedlings and beggarticks, in order, to verify the possibility of cultivating it with soybeans in a culture rotation system and its use as a herbicide. The experiments were carried out at the Laboratory of Plant Physiology of Universidade Estadual do Oeste do Paraná, Cascavel, Paraná, Brazil. The design was completely randomized and the evaluations were held daily. The parameters under analysis were: germination percentage, time and average speed of germination, and average root lenght. The data obtained underwent the F-Test and the mean values were compared through Tukey’s test, at a 5% probability level. The results confi rm the presence of allelopathic potential in camelina. It was found that this species can be considered an option for cultivating with soybean, due to the positive allelophatic interference caused in the culture and because it can be used in the control of weeds such as beggartick, having in mind that that it has delayed the development of the seedlings tested.

  14. Prymnesium parvum revisited: relationship between allelopathy, ichthyotoxicity, and chemical profiles in 5 strains

    DEFF Research Database (Denmark)

    Blossom, Hannah E.; Rasmussen, Silas Anselm; Andersen, Nikolaj Gedsted;

    2014-01-01

    Bioassay-guided discovery of ichthyotoxic algal compounds using in vivo fish assays is labor intensive,costly, and highly regulated. Since the mode of action of most known algal-mediated fish-killing toxinsis damage to the cell membranes in the gills, various types of cell-based bioassays are often...... (Oncorhynchusmykiss, 10 g) and the microalga Teleaulax acuta. No relationship between median effective concentrations(EC50s) on fish and median lethal concentrations (LC50s) on algae was observed in the 5 strains showingthat a microalgal bioassay cannot be used as a proxy for ichthyotoxicity. Fish were more sensitive...... to P.parvum with EC50s ranging from 6 × 103to 40 × 103cells ml−1, compared to the test alga where LC50sranged from 30 × 103to nearly non-toxic at 500 × 103cells ml−1. In addition, the cellular concentrationsof two recently suggested ichthyotoxins produced by P. parvum, the “golden algae toxins”, GAT...

  15. 紫花苜蓿化感作用的研究%Study on the allelopathy of alfalfa

    Institute of Scientific and Technical Information of China (English)

    李志华; 沈益新

    2005-01-01

    通过培养皿砂培法的生物检测方法研究3种浓度(5%,7.5%,10% w/v)的紫花苜蓿Medicago sativa茎叶浸提液对受体植物黑麦草Lolium multiflorum cv.barspectra,高羊茅Festuca arundinacea cv.vegas,白三叶Trifolium repeus cv.haifa,红三叶T.pratense cv.common,萝卜Raphanus sativus cv.sijihong和紫花苜蓿浸提液自身幼苗生长及发芽的影响,以探明紫花苜蓿的化感作用.结果表明:7.5%和10%的紫花苜蓿茎叶浸提液对受体苗长、根长均产生明显的抑制作用,且随浓度的升高,抑制作用加强;适宜浓度处理的紫花苜蓿茎叶浸提液对黑麦草、高羊茅、红三叶、白三叶种子萌发具有明显的影响,发芽率明显降低.

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

    Directory of Open Access Journals (Sweden)

    Fernando Bertol Carpanezzi

    2014-09-01

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

  17. Allelopathy of weed extracts on yield and its components in four cultivars of rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Ali MOHADESI

    2011-07-01

    Full Text Available Weeds are enemies to the crop plants and have harmful effects on agricultural crops due to several factors such as competition for space, light and nutrients. Allelopathic effects of weed extracts were studied on grain yield and yield components of rice. The experiment was carried out in the Rice Research Institute of Chaparsar, in 2006- 2007, in Tonekabon, Iran (latitude 36°54’ N, longitude 50° 40’E, level -20 m altitude, split plot on basis of randomized completely block design (RCBD with 4 replications. Results showed highly significant differences suggesting substantial to moderate phenotypic variability in most parameters evaluated except number of empty grain and 1000 -grain weight. Also, most yield of single plant obtained from umbrella sedge extract (28.5 g. It seems that umbrella sedge had least minerals in water; it could be affected positively on important factors such as yield of single plant compared to other treatments. Correlation coefficient analysis revealed significant and negative correlation between number of empty grain and yield of single plant (r=-0.42***. It’s implies that grain yield magnitude of Nemat cultivar exhibiting the least number of empty grain. Although yield of single plant was not affected neither by plant height nor number of tiller. In addition, irrigation water due to existence of high mineral and chemical pesticides in upstream of station farms severely was reduced yield. Also, results of this research showed that weed extracts haven’t very allelopathic effect on rice and in end of growing season, that’s better, plant leftover return and remain in field.

  18. Allelopathy of plasmid-bearing and plasmid-free organisms competing for two complementary resources in a chemostat.

    Science.gov (United States)

    Bhattacharyya, Joydeb; Smith, Hal L; Pal, Samares

    2012-01-01

    We consider a model of competition between plasmid-bearing and plasmid-free organisms for two complementary nutrients in a chemostat. We assume that the plasmid-bearing organism produces an allelopathic agent at the cost of its reproductive abilities which is lethal to plasmid-free organism. Our analysis leads to different thresholds in terms of the model parameters acting as conditions under which the organisms associated with the system cannot thrive even in the absence of competition. Local stability of the system is obtained in the absence of one or both the organisms. Also, global stability of the system is obtained in the presence of both the organisms. Computer simulations have been carried out to illustrate various analytical results.

  19. Expression of allelopathy in the soil environment: Soil concentration and activity of benzoxazinoid compounds released by rye cover crop residue

    Science.gov (United States)

    The activity of allelopathic compounds is often reduced in the soil environment where processes involving release from donor plant material, soil adsorption and degradation, and uptake by receptor plants naturally result in complex interactions. Rye (Secale cereale L.) cover crops are known to supp...

  20. Allelopathy in the tropical alga Lobophora variegata (Phaeophyceae): mechanistic basis for a phase shift on mesophotic coral reefs?

    Science.gov (United States)

    Slattery, Marc; Lesser, Michael P

    2014-06-01

    Macroalgal phase shifts on Caribbean reefs have been reported with increasing frequency, and recent reports of these changes on mesophotic coral reefs have raised questions regarding the mechanistic processes behind algal population expansions to deeper depths. The brown alga Lobophora variegata is a dominant species on many shallow and deep coral reefs of the Caribbean and Pacific, and it increased in percent cover (>50%) up to 61 m on Bahamian reefs following the invasion of the lionfish Pterois volitans. We examined the physiological and ecological constraints contributing to the spread of Lobophora on Bahamian reefs across a mesophotic depth gradient from 30 to 61 m, pre- and post-lionfish invasion. Results indicate that there were no physiological limitations to the depth distribution of Lobophora within this range prior to the lionfish invasion. Herbivory by acanthurids and scarids in algal recruitment plots at mesophotic depths was higher prior to the lionfish invasion, and Lobophora chemical defenses were ineffective against an omnivorous fish species. In contrast, Lobophora exhibited significant allelopathic activity against the coral Montastraea cavernosa and the sponge Agelas clathrodes in laboratory assays. These data indicate that when lionfish predation on herbivorous fish released Lobophora from grazing pressure at depth, Lobophora expanded its benthic cover to a depth of 61 m, where it replaced the dominant coral and sponge species. Our results suggest that this chemically defended alga may out-compete these species in situ, and that mesophotic reefs may be further impacted in the near future as Lobophora continues to expand to its compensation point.

  1. Effects of Cylindrospermopsin Producing Cyanobacterium and Its Crude Extracts on a Benthic Green Alga-Competition or Allelopathy?

    Science.gov (United States)

    B-Béres, Viktória; Vasas, Gábor; Dobronoki, Dalma; Gonda, Sándor; Nagy, Sándor Alex; Bácsi, István

    2015-10-30

    Cylindrospermopsin (CYN) is a toxic secondary metabolite produced by filamentous cyanobacteria which could work as an allelopathic substance, although its ecological role in cyanobacterial-algal assemblages is mostly unclear. The competition between the CYN-producing cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum, and the benthic green alga Chlorococcum sp. was investigated in mixed cultures, and the effects of CYN-containing cyanobacterial crude extract on Chlorococcum sp. were tested by treatments with crude extracts containing total cell debris, and with cell debris free crude extracts, modelling the collapse of a cyanobacterial water bloom. The growth inhibition of Chlorococcum sp. increased with the increasing ratio of the cyanobacterium in mixed cultures (inhibition ranged from 26% to 87% compared to control). Interestingly, inhibition of the cyanobacterium growth also occurred in mixed cultures, and it was more pronounced than it was expected. The inhibitory effects of cyanobacterial crude extracts on Chlorococcum cultures were concentration-dependent. The presence of C. ovalisporum in mixed cultures did not cause significant differences in nutrient content compared to Chlorococcum control culture, so the growth inhibition of the green alga could be linked to the presence of CYN and/or other bioactive compounds.

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

    Science.gov (United States)

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

    2012-04-01

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

  3. Proceedings, Annual Meeting, Aquatic Plant Control Research Program (20th) Held at Atlanta, Georgia on 18-21 November 1985.

    Science.gov (United States)

    1986-06-01

    terms of allelopathy and competitive plants. What I would like to see is some more comments on approaches by using beneficial species. The spikerush...potential allelopathy ? Ed Theriot: We were talking yesterday about new directions in our biological program: allelopathy and revegetation. The...that have the potential for infestation with problem species. We do not intend to concentrate mainly on allelopathy , although that will be one aspect

  4. Aquatic Plant Control Research Program. Allelopathic Aquatic Plants for Aquatic Plant Management: A Feasibility Study

    Science.gov (United States)

    1989-10-01

    block number) FIELD GROUP SUB-GROUP Allelopathy "Bioassay . Growth inhibition. Aquatic macrophytes. Biocontrol Lena minor 19. ABSTRACT (Continue on...Bibliography of Aquatic Plant Allelopathy ........ Al 2 ALLELOPATHIC AQUATIC PLANTS FOR AQUATIC PLANT MANAGEMENT; A FEASIBILITY STUDY Introduction Background 1...nutrients, water, and other biotic effects could have overriding effects that appear as competition or allelopathy . These biotic factors must be

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

    Institute of Scientific and Technical Information of China (English)

    韩彩霞; 彭瑞娟; 邰凤姣; 张弛; 邵华

    2015-01-01

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

  6. 多裂骆驼蓬对食荚豌豆的化感作用研究%Allelopathy of Peganum multisectum Maxim Bobr on edible podded pea

    Institute of Scientific and Technical Information of China (English)

    刘建新; 赵国林

    2007-01-01

    试验研究了多裂骆驼蓬醇提取物浸种对食荚豌豆种子萌发、幼苗生长及生理生化性状的影响.结果表明,多裂骆驼蓬醇提取物浸种显著抑制食荚豌豆种子的萌发和幼苗生长,萌发率、发芽指数和与萌发有关的淀粉酶活性降低,株高、根体积、根系和地上部干重减小,根茎比下降;多裂骆驼蓬醇提取物浸种处理的幼苗根系活力和叶片硝酸还原酶活性、叶绿素和可溶性蛋白质含量下降;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性降低,丙二醛(MDA)含量和过氧化物酶(POD)活性升高,根系过氧化物同工酶表达受抑.

  7. Allelopathy in agroforestry systems: the effects of leaf extracts ofCupressus lusitanica and threeEucalyptus spp. on four Ethiopian crops

    DEFF Research Database (Denmark)

    Lisanework N.; Michelsen, Anders

    1993-01-01

    The potential allelopathic effect ofCupressus lusitanica, Eucalyptus globulus, E. camaldulensis andE. saligna on seed germination, radicle and seedling growth was investigated with four crops:Cicer arietinum (chickpea),Zea mays (maize),Pisum sativum (pea) andEragrostis tef (teff). Aqueous leaf...

  8. 不同品种紫花苜蓿(Medicago sativa)的化感效应研究%Study on Allelopathy of Medicago sativa Stem Aqueous extracts

    Institute of Scientific and Technical Information of China (English)

    董晓宁; 高承芳; 李文杨; 张晓佩

    2009-01-01

    用砂培法研究紫花苜蓿(Medicago sativa)的六个品种苗期地上部分水浸提液对鸭茅(Dactylis glomerata L.)的化感效应.结果表明,紫花苜蓿六个品种茎叶水浸提液对鸭茅的化感效应在供试品种间差异显著.游客、苜蓿对鸭茅的种子发芽及幼苗生长有抑制作用,但游客却对鸭茅的苗干重有促进作用;三得利和赛迪对鸭茅的种子发芽、根长及根干重有抑制作用,却对苗生长的影响无显著差异.此外,供试紫花苜蓿浸提液对鸭茅的化感作用,随着浓度的升高,抑制作用随之增强.

  9. Preliminary Study on the Allelopathy of Piper nigrum L.%胡椒化感作用及其机理研究

    Institute of Scientific and Technical Information of China (English)

    占胜利; 朱朝华; 王兰英; 戴进用; 邓昌盛

    2009-01-01

    [目的]为建立合理的植物间套作机制、杂草的生物防治及研制新型植物源除草剂提供科学依据.[方法]通过测定胡椒叶水浸液对绿豆、萝卜、柱花草和刺苋种子萌发和幼苗生长的影响,对胡椒的化感作用及其机理进行研究.[结果]胡椒叶水浸液对萝卜、柱花草和刺苋的种子萌发表现出不同程度的抑制作用,且随着水浸液浓度的增加,抑制效应增大,达到0.05 g/ml时,抑制作用最强;对不同受体植物幼苗生长的影响表现为低浓度促进,高浓度抑制的双重效应.萝卜体内的超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性随着水浸液浓度的增加呈先升高后降低的趋势,丙二醛(MDA)含量增大.[结论]该研究为胡椒化感作用的开发和利用提供了科学的理论依据.

  10. Preliminary evaluation of the allelopathy of common garden plants%常见园林植物化感作用的初步评价

    Institute of Scientific and Technical Information of China (English)

    朱强; 邹梦辉; 安黎; 田曾元; 郭予琦

    2014-01-01

    以滤纸为基质初步评价了44种园林植物水浸液及最强抑制植物薄荷(Mentha haplocal yx)挥发油对萝卜(Raphanus sativus)的化感作用,以土壤为基质验证了白玉兰(Magnolia denudata)的化感作用,同时分析比较了化感作用离体测试的几种常用方法.结果表明,1)薄荷、白玉兰、枫杨(Pterocarla stenoptera)的化感抑制作用最强,综合效应(SE)分别为-0.72、-0.65、-0.38;海桐(Pittosporum tobira)、国槐(Sophora japonical)、银杏(Ginkgo biloba)的促进作用最强,SE值分别为0.47、0.41、0.26.2)薄荷挥发油具有极高的化感作用,在0.5mg· mL-1浓度下,显著抑制萝卜种子的萌发(P<0.05),极显著地抑制根和苗的生长(P<0.01),对苗高的抑制作用强于根长.3)盆栽试验证实白玉兰确实具有较强的化感作用.4)不同测试方法间存在较大差异,且差异程度还与受体植物的选择有关.研究结果为系统研究园林植物的化感作用奠定了基础.

  11. 黄花草木樨对杂草的化感作用研究%The Allelopathy of Yellow Sweet Clover on Weeds

    Institute of Scientific and Technical Information of China (English)

    邬彩霞; 刘苏娇; 赵国琦; 徐俊

    2015-01-01

    为探讨黄花草木樨(Melilotus officinalis)水浸提液对田间常见杂草的化感抑制作用以及利用黄花草木樨化感作用进行生物除草的可行性,采用生物检测法研究黄花草木樨水浸提液对藜(Chenopodium album)、臭草(Meli-ca scabrosa)、籽粒苋(Amaranthush ypochondriacus)、稗草(Echinochloa crus-galli)、萹蓄(Pol ygonum aviculare)、山苦荬(Ixeris chinensis)、车前草(Plantago asiatica)等7种杂草种子萌发和幼苗生长的化感效应;同时测定黄花草木樨干草粉对田间杂草生物量的抑制效应.结果表明:黄花草木樨茎叶水浸提液处理能显著抑制籽粒苋、山苦荬、藜、稗草及车前草的种子萌发(P<0.05);能显著抑制藜、籽粒苋、稗草、山苦荬、车前草的幼苗生长(P<0.05);黄花草木樨干草粉能有效降低田间杂草生物量,且对田间杂草的抑制效应随施用量的增加而增强,在施用量达90g·m-2时,对田间杂草数量和干重的抑制均达到显著水平(P<0.05).因此,黄花草木樨的抑草能力具有选择性,对不同种杂草的作用方式和作用强度存在差异;黄花草木樨干草粉的施用量在90g·m-2及以上时,能显著降低田间杂草的数量及重量.

  12. Alelopatia de Joanesia princeps Vell. e Casearia sylvestris Sw. sobre espécies cultivadas Allelopathy of Joanesia princeps Vell. and Casearia sylvestris Sw. on the cultivated species

    Directory of Open Access Journals (Sweden)

    Rafael Aguiar Capobiango

    2009-12-01

    Full Text Available Metabólitos secundários produzidos em algumas plantas podem provocar alterações no desenvolvimento de outras plantas ou até mesmo de outros organismos. O objetivo do trabalho foi avaliar o efeito alelopático de extratos aquosos de folhas de Joanesia princeps e Casearia sylvestris na germinação e no desenvolvimento inicial de plântulas de Brassica oleracea cv. capitata, Lactuca sativa cv. grand rapids e Lycopersicum esculentum. Foram testadas seis concentrações de cada extrato (10, 30, 50, 70, 90 e 100% além do controle água destilada. Os extratos aquosos de J. princeps e C. sylvestris reduziram e, ou inibiram significativamente o percentual de geminação das sementes, o crescimento inicial da parte aérea e do sistema radicular de todas as espécies cultivadas e causaram severas anormalidades nas plântulas. Os resultados indicam a existência de potencial alelopático de J. princeps e C. sylvestris.Secondary metabolites produced in some plant species can provoke development changes in other plants or even in other organisms. The objective of this work was to identify the possible allelopathic effects of the aqueous extracts of Joanesia princeps and Casearia sylvestris leaves in the germination and initial growth of Brassica oleracea cv. capitata, Lactuca sativa cv. grand rapids and Lycopersicum esculentum seedlings. Six concentrations of each extract (10, 30, 50, 70, 90 and 100% were tested besides distilled water control. The aqueous extracts of J. princeps and C. sylvestris significantly reduced the seed germination percentage, initial growth of the aerial section and root system of all cultivated species in which they caused severe seedlings damage. The results indicate existence of allelopathic potential in J. princeps and C. sylvestris.

  13. 清明菜的化感作用研究初探%Preliminary study on allelopathy of Gnaphlium affine D.Don

    Institute of Scientific and Technical Information of China (English)

    韩春梅

    2013-01-01

    Al elopathy of Gnaphlium af ine D.Don with dif erent parts (root, stem and leaf) aqueous extracts at dif erent concentrations (0、5、12.5、25 and 50 g/L) was studied and cabbage seeds were as the accepted bodies. The results showed that compared with the control, ef ects of root aqueous extracts of Gnaphlium af ine on germination rate and seedling growth of cabbage tended to the same tendency that lower concentration accelerated and higher concentration inhibited. While stem and leaf aqueous extract inhibited germination rate and seedling growth and inhibition increased with the increase in concentration of Gnaphlium af ine aqueous extracts. While under the same concentration, the order of ef ect of Gnaphlium af ine aqueous extracts on seed germination and seedling growth of radish was leaf>stem>root.%以白菜种子为受体,初步研究了清明菜不同部位(根、茎和叶)、不同浓度(0、5、12.5、25和50 g/L)的水浸液的化感作用。结果表明:与对照相比,根水浸液对白菜种子的萌发率及幼苗生长均表现为低浓度促进、高浓度抑制的作用,而茎和叶水浸液则一直表现为抑制作用,并且随着浓度的增加,其抑制效应在增强;而在同一浓度下,清明菜水浸液对白菜种子萌发及幼苗生长的影响强度顺序均为叶>茎>根。

  14. 毛白杨根系化感作用%Preliminary Study of Allelopathy of Root Aqueous Extracts from Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    朱美秋; 张丽丽; 王辉; 袁玉欣

    2014-01-01

    以杨-农复合经营中的3种主要间作物(紫花苜蓿、萝卜、小麦)及杨树种子为受体,研究8年生、45年生毛白杨根系水浸提液(0.001、0.020、0.050、0.100 g· mL-1)对4种受体种子萌发和幼苗生长的影响。结果表明,8年生和45年生毛白杨根系水浸提液在0.050、0.100 g· mL-1时,显著抑制4种受体种子的萌发(小麦发芽率除外)和幼苗的生长(杨树苗高生长除外),且随浓度的降低,抑制作用逐渐减小,低浓度时有时抑制作用不显著,甚至有促进作用。紫花苜蓿和萝卜种子的发芽率和发芽指数对毛白杨化感作用更敏感;小麦幼苗的高生长、杨树幼苗根生长对毛白杨化感作用更敏感。另外,8年生毛白杨根系水浸提液对4种受体种子萌发和幼苗生长的抑制作用强于45年生毛白杨,且差异显著。%We adopted root aqueous extracts from Populus tomentosa of different age (8 years and 45years) at different concentrations (0.001,0.020,0.050 and 0.100 g· mL-1 ) to deal with the seed germination and seedling growth of three common agronomic crops (Wheat,Alfalfa,Radish ) and Poplar.The results showed that the root aqueous extracts of P.tomentosa of both 8 years and 45 years had negative effects on seeds germination ,seedlings and roots growth of Wheat ,Alfalfa,Radish and poplar at higher concentration (0.050 and 0.100 g· mL-1),and the inhibited effects decreased gradually with decreasing concentration of root aqueous ex -tract.Occasionally their effects were not significant at lower concentration and even the root aqueous extracts increased seed germina -tion and seedling growth.However ,the root aqueous extract of 45 years had positive effects on the seedling growth of poplar ,and had no effects on the seed germination of Wheat.Variables related to seed germination were more susceptible for Alfalfa ,Radish than for Wheat and Poplar ,while seeding height-related variables more susceptible for Wheat than others , and root height-related variables more susceptible for Poplar.In general ,the inhibited effects of root aqueous extracts of 8 years on both seeds germination and seed-lings growth of plants tested were more intensive than root aqueous extracts of 45 years.The effects of different age root aqueous ex-tracts on seeds germination and seedlings growth of Wheat and Poplar were significantly different ,as well as on seeds germination of Alfalfa.

  15. 当归自毒作用和其对不同作物的化感效应%Autotoxicity of Angelica sinensis and Allelopathy on Tested Plants

    Institute of Scientific and Technical Information of China (English)

    王田涛; 王琦; 王惠珍; 张恩和

    2012-01-01

    In order to find the succession cropping obstacle of Angelica sinensis (a common traditional Chinese medicinal plant) planting, the effects of aqueous extract from Angelica sinensis root on the germination rates of Angelica sinensis , Brassica campestris , Triticum aestivum , Vicia faba were studied in this paper. Results showed that the autotoxicity of Angelica sinensis was high and increased with increased a-queous concentration. The germination rates of Angelica sinensis were 36. 25% , 5. 83% , 0. 83% and 0% when the concentrations of aqueous were 0. 0125, 0. 0250, 0. 0500 and 0. 1000 g ?mL-1 , respectively. Inhibiting effects of Angelica sinensis were ordered as Brassica campestris>Triticum aestivum>Vicia faba. At the same concentration of aqueous, the inhibiting effects of aqueous on root growth were higher than sprout growth of Brassica campestris and Triticum aestivum , but the effect on root growth were smaller than sprout growth of Vicia faba. And the germination rate and germination index of Vicia faba was higher than those of Brassica campestris and Triticum aestivum. It is concluded that autotoxicity of Angelica sinensis is an obstacle in succession cropping system, and inhibiting effects of Angelica sinensis on Vicia faba were smaller then on Brassica campestris and Triticum aestivum. Vicia faba is an alternative crop for rotation systems to reduce the autotoxicity of Angelica sinensis%为探讨当归(Angelica sinensis)连作障碍产生的原因和建立合理的轮作制度,在室内采用离体生测方法,研究当归水浸提物对当归、油菜(Brassica campestris)、小麦(Triticum aestivum)和蚕豆(Vicia faba)的化感效应.结果表明:当归具有较强的自毒作用,且自毒作用随浓度增加而增加;当归水浸液浓度为0.0125,0.0250,0.0500和0.1000 g·mL-1时,当归发芽率分别为36.25%,5.83%,0.83%和0%.当归水浸提物对3种植物种子萌发均表现为化感抑制作用,并且化感抑制作用随浓度增加而增加,种子萌发次序是油菜>小麦>蚕豆.在同一浓度处理下,对小麦和油菜胚根的化感抑制作用大于胚芽,而对蚕豆胚根的化感抑制作用小于胚芽.油菜和小麦的萌发率和萌发指数大于蚕豆.当归水浸提物对去胚乳小麦幼芽、幼根的平均抑制率分别为5.63%和18.01%;当归对黑暗条件下培养的油菜幼芽、幼根的抑制率分别为16.25%和50.36%,表明当归化感物质对植物非光合作用的抑制作用强于光合作用.因此,当归的自毒作用是造成连作障碍的原因之一;当归对蚕豆的化感作用小于油菜和小麦,蚕豆可以用于当归轮作体系,缓解因自毒作用而引起的连作障碍.

  16. Alelopatia em extratos de frutos de juazeiro (Ziziphus joazeiro Mart. - Rhamnaceae Allelopathy caused by fruit extract of juazeiro (Ziziphus joazeiro Mart. - Rhamnaceae

    Directory of Open Access Journals (Sweden)

    Andreya Kalyana de Oliveira

    2009-12-01

    Full Text Available O objetivo deste trabalho foi avaliar o potencial alelopático do extrato de frutos de juazeiro (Ziziphus joazeiro Mart. sobre as sementes de alface (Lactuca sativa. O experimento foi conduzido em delineamento inteiramente casualizado com 4 repetições e cinco tratamentos (0%, 25%, 50%, 75% e 100% de concentração do extrato bruto. O extrato bruto foi obtido após a extração manual da polpa do fruto e agitação com água em liquidificador utilizando-se 50g de polpa para 500ml de água, e o mesmo foi feito com a casca do fruto. Os resultados mostraram efeito do extrato dependendo da concentração. As maiores concentrações do extrato (100%, 75% e 50% da polpa dos frutos Z. joazeiro apresentaram efeito alelopático desfavorável sobre a germinação de alface, reduzindo-a em 100%, 98,75% e 82,5% respectivamente. O extrato das cascas dos frutos nas concentrações de 75% e 100% reduziu a germinação da alface em 28,75% e 78,75%.This study aimed to identify the allelopathic activity of extracts obtained from Ziziphus joazeiro fruits on the germination of Lactuca sativa L. A randomized design was used with four replications and five treatments (0%, 25%, 50%, 75% and 100% concentration of the crude extract. The crude extract was obtained after manual extration of the fruit pulp and agitation with water in a blender using 50g of pulp in 500ml of water. The same was done with the fruit rind. The results showed the effect of the extract depending on concentration. The greatest extract concentrations (100%, 75% and 50% of Z. joazeiro fruit pulp had an unfavorable allelopathic effect on lettuce germination, having reduced it by 100%, 98.75% and 82.5% respectively. The extract of the fruits rinds in concentrations of 75% and 100% reduced lettuce germination by 28.75% and 78.75%.

  17. Alelopatia de extratos aquosos de canela-sassafrás (Ocotea odorifera (Vell. Rohwer Allelopathy of Brazilian sassafras (Ocotea odorifera (Vell. Rohwer aqueous extracts

    Directory of Open Access Journals (Sweden)

    Flávia Maria da Silva Carmo

    2007-09-01

    Full Text Available Estudos de alelopatia investigam os efeitos positivos e negativos que metabólitos secundários de plantas, microrganismos ou fungos exercem sobre o desenvolvimento de indivíduos vizinhos. Nesse trabalho foram investigados os efeitos de extratos aquosos de folhas, cascas de tronco e cascas de raízes de canela-sassafrás (Ocotea odorifera (Vell. Rowher sobre a germinabilidade das sementes, desenvolvimento do sistema radicular e da parte aérea, teor de clorofila da parte aérea e respiração das células radiculares de plântulas de sorgo (Sorghum bicolor L. Moench cv. Embrapa BR 303. Os extratos foram preparados adicionando o material vegetal seco e moído oriundo de cada órgão à água destilada e deionizada na proporção 1:10 (p/v. Após agitação constante por 24 h, as soluções foram decantadas e filtradas através de papel de filtro sob vácuo, constituindo os extratos testados. Os extratos aquosos de cascas de tronco e de raízes causaram inibição do desenvolvimento do sistema radicular das plântulas de sorgo e a sua parte aérea teve o crescimento estimulado pelo extrato de cascas de raízes. Os extratos de folhas e de cascas de tronco induziram aumento da biomassa fresca do sistema radicular e diminuição significativa do teor de clorofila. Todos os extratos causaram efeitos negativos sobre a respiração radicular das plântulas de sorgo. Concluiu-se que metabólitos secundários da canela-sassafrás causaram alterações metabólicas e morfológicas nas plantas de sorgo e que, portanto, a presença de canela-sassafrás no ambiente pode desencadear efeitos similares sobre outras espécies vegetais na sua vizinhança.Allelopathic studies investigate the positive and negative effects of secondary metabolites of plants, microorganisms and fungi on the development of neighboring individuals. In this work, the allelopathic effects of aqueous extracts of leaves, bark and root bark of Brazilian sassafras (Ocotea odorifera (Vell. Rowher on seed germination, root and shoot growth, chlorophyll content and respiratory activity of the root cells of sorghum seedlings (Sorghum bicolor (L Moench cv. Embrapa BR 303 were analyzed. The extracts were prepared by adding dried, powdered plant material to distilled non-ionized water at 1:10 (w/v. After continuous agitation for 24 h, these solutions were decanted and vacuum-filtered through filter paper, thus constituting the tested extracts. Bark and root bark aqueous extracts caused root growth inhibition in sorghum seedlings while shoot growth was stimulated by the root bark extract. Leaf and bark extracts induced an increase in wet root biomass and a decrease in chlorophyll content. All extracts caused negative effects on sorghum seedling root cell respiration. We concluded that secondary metabolites from Brazilian sassafras caused metabolic and morphological alterations in the sorghum seedlings and the presence of these plants in the environment can cause similar effects on other neighboring plant species.

  18. Comparing susceptibility of eastern and western U.S. grasslands to competition and allelopathy from spotted knapweed (Centaurea stoebe L. subsp. micranthos (Gugler) Hayek)

    Science.gov (United States)

    Centaurea maculosa is native to Eurasia and is invasive in the western portion of the US. Negative impacts of C. maculosa present in the eastern US have not been recorded. In this study, we examine the effects of C. maculosa on species diversity on an eastern grassy bald, compare the competitive a...

  19. A less saline Baltic Sea promotes cyanobacterial growth, hampers intracellular microcystin production, and leads to strain-specific differences in allelopathy.

    Science.gov (United States)

    Brutemark, Andreas; Vandelannoote, Angélique; Engström-Öst, Jonna; Suikkanen, Sanna

    2015-01-01

    Salinity is one of the main factors that explain the distribution of species in the Baltic Sea. Increased precipitation and consequent increase in freshwater inflow is predicted to decrease salinity in some areas of the Baltic Sea. Clearly such changes may have profound effects on the organisms living there. Here we investigate the response of the commonly occurring cyanobacterium Dolichospermum spp. to three salinities, 0, 3 and 6. For the three strains tested we recorded growth, intracellular toxicity (microcystin) and allelopathic properties. We show that Dolichospermum can grow in all the three salinities tested with highest growth rates in the lowest salinity. All strains showed allelopathic potential and it differed significantly between strains and salinities, but was highest in the intermediate salinity and lowest in freshwater. Intracellular toxin concentration was highest in salinity 6. In addition, based on monitoring data from the northern Baltic Proper and the Gulf of Finland, we show that salinity has decreased, while Dolichospermum spp. biomass has increased between 1979 and 2013. Thus, based on our experimental findings it is evident that salinity plays a large role in Dolichospermum growth, allelopathic properties and toxicity. In combination with our long-term data analyses, we conclude that decreasing salinity is likely to result in a more favourable environment for Dolichospermum spp. in some areas of the Baltic Sea.

  20. ROLE OF ALLELOPATHY IN THE STIMULATORY AND INHIBITORY EFFECTS OF HAIRY VETCH COVER CROP RESIDUE IN NO-TILLAGE SUSTAINABLE PRODUCTION SYSTEMS

    Science.gov (United States)

    Cover crops can provide multiple benefits to sustainable cropping systems including building soil organic matter, controlling soil and nutrient losses from fields, moderating radiation and moisture exchange, releasing nutrients for subsequent crops, and suppressing weed and pest populations. Many o...

  1. A less saline Baltic Sea promotes cyanobacterial growth, hampers intracellular microcystin production, and leads to strain-specific differences in allelopathy.

    Directory of Open Access Journals (Sweden)

    Andreas Brutemark

    Full Text Available Salinity is one of the main factors that explain the distribution of species in the Baltic Sea. Increased precipitation and consequent increase in freshwater inflow is predicted to decrease salinity in some areas of the Baltic Sea. Clearly such changes may have profound effects on the organisms living there. Here we investigate the response of the commonly occurring cyanobacterium Dolichospermum spp. to three salinities, 0, 3 and 6. For the three strains tested we recorded growth, intracellular toxicity (microcystin and allelopathic properties. We show that Dolichospermum can grow in all the three salinities tested with highest growth rates in the lowest salinity. All strains showed allelopathic potential and it differed significantly between strains and salinities, but was highest in the intermediate salinity and lowest in freshwater. Intracellular toxin concentration was highest in salinity 6. In addition, based on monitoring data from the northern Baltic Proper and the Gulf of Finland, we show that salinity has decreased, while Dolichospermum spp. biomass has increased between 1979 and 2013. Thus, based on our experimental findings it is evident that salinity plays a large role in Dolichospermum growth, allelopathic properties and toxicity. In combination with our long-term data analyses, we conclude that decreasing salinity is likely to result in a more favourable environment for Dolichospermum spp. in some areas of the Baltic Sea.

  2. Potencial alelopático de duas neolignanas isoladas de folhas de Virola surinamensis (Myristicaceae Allelopathy potential of two neolignans isolated from Virola surinamensis (Myristicaceae leaves

    Directory of Open Access Journals (Sweden)

    F.C. Borges

    2007-03-01

    Full Text Available Este trabalho teve por objetivos isolar, identificar e caracterizar a atividade alelopática de substâncias químicas presentes nas folhas de Virola surinamensis. O processo de isolamento e identificação das substâncias químicas envolveu o uso de solventes orgânicos e de Ressonância Magnética Nuclear (RMN ¹H, RMN 13C e RMN 13C-DEPT, espectro de COSY e de HETCOR. A avaliação da atividade alelopática foi realizada em bioensaios de germinação de sementes, em condições de 25 ºC de temperatura constante e fotoperíodo de 12 horas, e de desenvolvimento da radícula e do hipocótilo, com 25 ºC de temperatura constante e fotoperíodo de 24 horas, empregando-se concentrações variando de 1,0 a 8,0 mg L-1. Como plantas receptoras, foram utilizadas as espécies daninhas Mimosa pudica, Senna obtusifolia e Senna occidentalis. Foram isoladas e identificadas duas neolignanas: a surinamensina e a virolina. A tendência geral observada nos resultados foi de aumento da intensidade dos efeitos alelopáticos inibitórios em função do aumento da concentração, com inibições máximas obtidas, sempre, na concentração de 8,0 mg L-1. A surinamensina apresentou maior potencial para inibir a germinação e o desenvolvimento da radícula e do hipocótilo do que a virolina, independentemente da espécie receptora e do fator da planta analisado. Considerando-se as intensidades dos efeitos promovidos sobre os três fatores das plantas, o desenvolvimento da radícula e o do hipocótilo foram mais intensamente inibidos pelas duas substâncias do que a germinação das sementes. À exceção dos efeitos verificados sobre o desenvolvimento do hipocótilo, malícia foi a espécie de maior sensibilidade aos efeitos alelopáticos das duas neolignanas, enquanto mata-pasto foi aquela que evidenciou inibições de menor magnitude.The objective of this research was to isolate, identify and characterize the allelopathic activity of chemical compounds in Virola surinamensis leaves. The process of isolation and identification of chemicals compounds involved the use of organic solvents and Magnetic Nuclear Resonance (MNR ¹H, MNR 13C and MNR 13C-DPT, HETCOR and COSY specter. Allelopathic activity was evaluated by bioassays, under constant temperature of 25 ºC and 12-h photoperiod for seed germination and 25 ºC of constant temperature and 24-hour photoperiod for radicle and hypocotyl elongation, at concentrations ranging from 1.0 mg L-1 to 8.0 mg L-1. The receiving plants used were the weeds Mimosa pudica, Senna obtusifolia and Senna occidentalis. Two neolignans were isolated and identified: surinamensin and virolin. The general trend observed was a positive relation between allelopathic effects and the concentration of the compounds, with maximum inhibition obtained at the concentration of 8.0 mg L-1. Surinamensin presented greater potential to inhibit seed germination and radicle/hypocotyl elongation than virolin, regardless of the receiving species or plant parameter. Radicle and hypocotyl elongation were more intensely inhibited than seed germination by the two compounds. Except for the effects promoted on hypocotyl elongation, the species M. pudica was the most sensitive to the allelopathic effects caused by the two neolignans.

  3. Allelopathy of decomposed maize straw products on three soil-born diseases of wheat and the analysis by GC-MS

    Institute of Scientific and Technical Information of China (English)

    QI Yong-zhi; ZHEN Wen-chao; LI Hai-yan

    2015-01-01

    In northern China, the soil-born diseases of wheat have been getting more and more serious under a new farming system that returns maize straw to the ifeld. In order to investigate the alelopathy of the decomposed maize straw products on three soil-born diseases of wheat, culture dish and pot experiments were conducted and the compounds in the products were identiifed by gas chromatography-mass spectrometry (GC-MS). Culture dish experiments showed that the mycelial growth, sclerotia formation amount and total weight ofRhizoctonia cerealiswere promoted at concentrations of 0.03, 0.06 and 0.12 g mL–1 and inhibited at concentration of 0.48 g mL–1 of the decomposed products. No signiifcant effects were found of the product concentrations on average weight of the sclerotia. Mycelial growth ofGaeumannomyces graminis was promoted at almost al concentrations except the highest one. Mycelial growth and spore germination ofBipolaris sorokiniana were signiifcantly inhibited by al concentrations of the decomposed products, with enhanced inhibition effects along with the increased concentrations. The length, number and dry weight of roots together with the root superoxide dismutase activity were promoted by the lowest concentration (0.03 g mL–1), with a synthetic effect index of 0.012, and inhibited by other concentrations. The ion leakage of roots was increased and the root peroxidase activity of roots was lowered by al the treatments. Pot experiments revealed that occurrence of the sharp eyespot was reduced by 0.03 and 0.06 g mL–1 of decomposed products after irrigation. However, the incidence rates and disease indexes were signiifcantly increased by 0.12, 0.24 and 0.48 g mL–1 of decomposed products. The results indicated that incidence rates and disease indexes of the take-al were signiifcantly promoted after being irrigated with the decomposed products, while occurrences of the common rot didn’t change, signiifcantly. GC-MS results showed that the compounds of the decomposed products included organic acids, esters, hydrocarbons, amides and aldehydes, with the proportions 25.26, 24.01, 17.22, 14.39 and 7.73%, respectively. Further analysis investigated that the alelochemicals identiifed in straw decomposed products contained p-hydroxybenzoic acid (9.21%), dibutyl phthalate (6.94%), 3-phenyl-2-acrylic (5.06%), 4-hydroxy-3,5-dimethoxybenzoic acid (2.26%), hexanoic acid (1.73%), 8-octadecenoic acid (1.06%), 3-(4-hydroxy-3-methoxy-phenyl)-2-propenoic acid (1.04%), 4-hydroxy-3-methoxy-benzoic acid (0.94%) and salicylic acid (0.94%).

  4. Golden Algae Control: Efficacy of Hydraulic Manipulations in Coves of Lake Granbury

    Science.gov (United States)

    2013-04-01

    phytoplankton through allelopathy , many ERDC/EL CR-13-1 45 zooplankton predators through toxicity, and preys on heterotrophic bacteria and some small...algal toxicity and allelopathy : A focus on historical Prymnesium parvum blooms in a Texas reservoir. Ecological Modelling 227:147-161. Grover, J. P...Brooks. 2012. Modeling of plankton community dynamics characterized by algal toxicity and allelopathy : A focus on historical Prymnesium parvum blooms

  5. Approaches to Golden Algae Control: In-Lake Mesocosm Experiments

    Science.gov (United States)

    2012-04-01

    2009), suppression of competitors through allelopathy (Fistarol et al. 2003, 2005; Granéli and Johansson 2003; Roelke et al. 2007; Errera et al. 2008...assessment of microcystin-LR: A case study of allelopathy to Prymnesium parvum. Journal of Plankton Research 33: 319-332. Johansson, N., and E...Lehtinen, C. Legrand, P. Kuuppo, and T. Tamminen. 2005. Haemolytic activity and allelopathy of the haptophyte Prymnesium parvum in nutrient- limited and

  6. Management of Florida Scrub for Threatened and Endangered Species

    Science.gov (United States)

    1998-12-01

    now known to be dissimilar in composition and structure based on differences in soils and disturbance regimes; allelopathy (the ability to produce...hearty enough to survive under this nutrient stress will grow on scrub soils. Some scrub plants may use allelopathy to avoid competition for scarce...seed and by rhizomes, which can be transported on equipment (e.g., bulldozers; FNAI 1994b, USFWS 1995). Rhizoma- tous spread and allelopathy aid

  7. Dinoflagellate Toxins Responsible for Ciguatera Food Poisoning

    Science.gov (United States)

    1989-12-20

    benthos under temperature stress, despite the presence of other faster- growing, more temperature-tolerant algae. The hypothesis regarding allelopathy is...density of a culture (Fig. 11) which in turn may regulate ammonium uptake (Fig. 12). This link also supports the hypothesis regarding allelopathy . An

  8. Integrated Control and Assessment of Knapweed and Cheatgrass on Department of Defense Installations

    Science.gov (United States)

    2005-01-01

    Vepachedu, R., Gilroy, S., Callaway, R.M., Vivanco, J. M., 2003. Allelopathy and exotic plant invasion: from molecules and genes to species interactions... allelopathy respectable. Science 301:1337-1338. Fitter, A. H., Graves, J. D., Watkins, H. K., Robinson, D., Scrimgeour, C. l998. Carbon transfer

  9. QTL Information Table: 417 [Q-TARO

    Lifescience Database Archive (English)

    Full Text Available Others Others allelopathy RFLP C)Interval RIL Zhong 156 Gumei 2 RZ395 RZ264 pha Xu,... Z., He, Y., Cui, S., Zhao, M., Zhang, X., and Li, D. (2003). Genes mapping on rice allelopathy against barnyardgrass. Ying Yong Sheng Tai Xue Bao 14, 2258-2260. ...

  10. A Review of the Growth Habits and Restoration Issues for Clitoria fragrans and Polygonella basiramia

    Science.gov (United States)

    2007-06-01

    Allelopathy by Florida rosemary may also play a role (Fisher et al. 1994). Most scrub species establish seedlings during winter. Fire kills seeds...1994. In search of allelopathy in the Florida scrub; the role of terpenoids. Journal of Chemical Ecology 20: 1355–1380. Hawkes, C.V., and E.S

  11. 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.

  12. Allelopathy of Ruppia Maritima on Chlorella Vulgaris in reclaimed wastewater%川蔓藻在再生水体中对普通小球藻的化感作用

    Institute of Scientific and Technical Information of China (English)

    王卫红; 季民; 王苗苗; 张楠; 唐运平; 张志杨

    2007-01-01

    采用川蔓藻植株体与普通小球藻在再生水中共培养和使用再生水种植川蔓藻的种植水纯培养普通小球藻的方法,在实验室条件下研究了在滨海再生水河道中生长的沉水植物川蔓藻对小球藻的化感作用.结果表明,川蔓藻对普通小球藻具有显著的抑制作用.在共培养实验中,96 h的抑制率为88.86%;在种植水纯培养实验中,96 h的抑制率为48.91%.川蔓藻的种植水对普通小球藻的化感作用系数平均为-0.2448.川蔓藻的叶和根的种植水对普通小球藻均有抑制效果,96 h的抑制率为叶34.71%,根14.12%;平均的化感作用系数叶为-0.1317,根为-0.0901;川蔓藻的根和叶均能释放化感物质,但抑制小球藻的化感物质主要通过叶释放.

  13. Comparative study of allelopathy effects of aqueous extract from different parts of coriander on rice seeds%芫荽不同部位浸提液对水稻种子化感效应比较研究

    Institute of Scientific and Technical Information of China (English)

    李仰锐; 吴秋燕; 吴艳波

    2011-01-01

    以芫荽为供体材料、水稻为受体材料,探讨芫荽不同部位不同浓度浸提液对水稻种子的化感作用,结果表明:不同浓度芫荽器官(根、茎、叶)浸提液对水稻种子萌发有较强的抑制作用,随处理浓度升高,抑制作用增强;在相同浓度下,不同芫荽器官的浸提液对水稻种子萌发和生长的化感作用强度依次为茎>叶>根.

  14. 不同发育期反枝苋对黄瓜根缘细胞的化感作用%The allelopathy of different development stages of Amaranthus retroflexus L.on root border cells of cucumber

    Institute of Scientific and Technical Information of China (English)

    刘爽; 马丹炜

    2009-01-01

    以黄瓜为实验材料,采用悬空气培养法研究了不同发育期反枝苋水浸提液对根缘细胞的化感效应.结果表明:在反枝苋水浸提液作用下,黄瓜根果胶甲基酯酶(PME)活性升高,但随着水浸提液浓度的升高,这种促进效应逐渐降低;而黄瓜根缘细胞存活率随着水浸提液浓度的升高而下降.相同发育期反枝苋不同部位的化感作用差异不显著,不同发育时期反枝苋化感作用差异较为明显,其化感作用以幼苗期最强,现蕾期次之,成熟期最弱.推测化感作用是反枝苋发育初期取得竞争优势,迅速占领生态位的原因之一.

  15. Allelopathie Effect of Water Extracts from Two Submerged Macrophytes on Growth of Scenedesmus obliquus%两种沉水植物浸提液对斜生栅藻的化感效应

    Institute of Scientific and Technical Information of China (English)

    杨琳; 吴伟; 胡庚东; 瞿建宏; 陈家长; 李成君

    2008-01-01

    采用玻璃水族箱及恒温光照培养箱,分别研究了两种沉水植物伊乐藻(Elodea canadensis)和蓖齿眼子菜(Potamogetonpectinatus L.)的浸提液对斜生栅藻(Scenedesmus obliquus)的化感效应.结果显示,这两种沉水植物的浸提液均对斜生栅藻的生长具有化感效应,且都表现为"低促高抑"的现象.伊乐藻和蓖齿眼子菜20%浸提液试验组对斜生栅藻有明显的促生长效应,试验第7 d时,其藻细胞浓度分别为同期对照组的237%和180%.伊乐藻和篦齿眼子菜50%~90%浸提液试验组对斜生栅藻的生长有不同程度地抑制,且抑制作用随着浸提液浓度的增加而逐渐增强.试验第7 d时,伊乐藻和蓖齿眼子菜90%浸提液试验组藻细胞浓度分别为同期对照组的38%和32%.从对藻类生长的抑制效果上看,伊乐藻浸提液对斜生栅藻的EC50(6 d)为70%,篦齿眼子菜浸提液对斜生栅藻的EC50(6 d)为55%,表明了眼子菜浸提液对斜生栅藻的抑制效果较伊乐藻浸提液好.

  16. 不同落叶提取液对豇豆种子化感效应的研究%Research of Allelopathy Effects of Dead Leaves on Vigna unguiculata

    Institute of Scientific and Technical Information of China (English)

    白雪梅; 伍秋琳; 汤津津; 孙杰; 李仰锐

    2011-01-01

    以豇豆种子为受体材料,研究5种落叶提取液对豇豆种子的化感作用.结果表明:不同浓度的落叶提取液对豇豆种子发芽和幼苗的生长有不同的影响,落叶提取液对种子萌发表现出高浓度抑制、低浓度促进的现象.对幼苗的生长有一定的促进作用,小叶榕、黄桷兰落叶提取液不同程度地抑制豇豆的干物质重,且随着浓度的增加,抑制作用逐渐增强;桂花落叶提取液对豇干物质重的影响呈现出低浓度促进、高浓度抑制现象.

  17. The Allelopathy of the Water Extract from Wedelia Trilobata on Several Economic Crops%南美蟛蜞菊对几种经济作物的生化他感作用

    Institute of Scientific and Technical Information of China (English)

    陈贤兴; 丁炳扬; 沈夕良; 何献武

    2005-01-01

    研究了外来植物南美蟛蜞菊(Wedelia trilobata(L.)A.S.Hitche)茎叶水浸提液对绿豆(Vigna radiata Linn.)、萝卜(Raphaus sativus Linn.)、青菜(Brassica chinensis Linn.)等经济作物的生化他感作用.结果表明,南美蟛蜞菊的茎叶水提液对几种供试植物种子的发芽指数、萌发率及幼苗的苗高和根长均有不同程度的抑制作用.

  18. Allelopathy of Flavonoid Extract from Carya catha yensis Exocarp on Wheat and Mung Bean Seedlings%山核桃外果皮黄酮提取液对小麦和绿豆幼苗的化感效应

    Institute of Scientific and Technical Information of China (English)

    陈向明; 马云飞

    2010-01-01

    以盆栽小麦和绿豆幼苗为材料,研究了7个浓度山核桃外果皮黄酮提取液(0.02~0.14 mg·L-1)处理对小麦和绿豆幼苗生长及其叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性、氧自由基(O2)、丙二醛(MDA)含量、相对电导率的影响.结果显示:在试验浓度范围内,各处理对小麦和绿豆生长具有促进作用;0.06~0.08 mg·L-1黄酮提取液对小麦苗高和根长的影响极显著(P<0.01),0.06 mg·L-1时根长和苗高的化感效应指数(RI)分别为0.136和0.120;0.12 mg·L-1黄酮提取液对绿豆胚根和胚轴具有极显著促进作用,对下胚轴和胚根的化感效应指数分别为0.147和0.123;适宜浓度黄酮提取液能显著提高小麦和绿豆幼苗叶片SOD、POD的活性,同时显著降低其O2产生速率、MDA含量和相对电导率.研究表明,适宜浓度的山核桃外果皮黄酮提取液具有促使小麦和绿豆幼苗生长、提高其叶片保护酶活性和增强细胞膜结构稳定性的作用.

  19. 假臭草等12种植物对白花鬼针草幼苗的化感作用%Allelopathy of 12 Species Including Eupatorium catarium on Bidens alba Seedlings

    Institute of Scientific and Technical Information of China (English)

    陈志云; 梁水凤; 李东文; 冯卓森; 李伟华; 彭长连; 田兴山; 周先叶

    2011-01-01

    用具有化感作用或潜在抑草活性的12种植物的叶片水浸液对白化鬼针草(Bidens alba)幼苗进行处理,对其幼苗的生长进行研究,以期筛选出对白花鬼针草生长有较强抑制作用的植物种类.结果表明,12种供体植物叶片水浸液(0.05 g DW mL-1)均能显著抑制白花鬼针草幼苗的生长(P<0.05),综合化感效应(SE)均为负值(≤-0.2),抑制强度依次为假臭草(Eup atorium catarium)>胜红蓟(Ageratum conyzoides>海芋(Alocasia macrorrhiza)>水茄(Solanum torvum)>马缨丹(Lantana camara)>薇甘菊(Mikania micrantha)>构树(Broussonetia papyrifera)>南美蟛蜞菊(Wedelia trilobata)>三裂叶薯(Ipomoea triloba)>葛藤(Pueraria lobata)>鸡矢藤(Paederia scandens)>五爪金龙(lpomoea cairica),其中假臭草叶水浸液浓度仅为0.04 g DW mL-1时就可以使白花鬼针草死亡.假臭草和胜红蓟的茎水浸液也可以显著抑制白花鬼针草的生长(P<0.05),抑制效果略低于叶水浸液.回归分析表明,假臭草叶水浸液浓度与白花鬼针草的生物量等指标之间有线性回归关系(R2> 0.85,P<0.001),随着水浸液浓度的增加,白花鬼针草的生物量等指标下降.防除白花鬼针草时使用假臭草和胜红蓟的茎、叶水浸液,其有效浓度低且资源丰富,可作为白花鬼针草天然除草剂的主要资源植物.

  20. Allelopathy Effects of Straw and Green Manure on Lettuce Seed%秸秆及绿肥浸提液对莴苣种子的化感作用

    Institute of Scientific and Technical Information of China (English)

    魏云霞; 鲁剑巍; 李小坤; 薛欣欣; 王素萍

    2013-01-01

    采用室内培养试验,通过测定稻草、油菜秸秆、紫云英及紫云英+油菜浸提液对莴苣种子发芽及幼苗生长的影响,研究秸秆及绿肥浸提液对莴苣种子的化感作用.结果表明:各秸秆及绿肥浸提液处理均会延迟莴苣种子的发芽速度,且高浓度抑制种子萌发;各浸提液处理对莴苣幼苗苗高表现为低促高抑,而对根长表现为抑制;莴苣幼苗鲜质量及于质量均随各浸提液浓度的增加先增加后降低,其中稻草、油菜秸秆、紫云英及紫云英+油菜浸提液对幼苗鲜质量的最大促进作用分别为27.33%、27.52%、1.28%、19.24%;不同浓度下,稻草、紫云英浸提液对莴苣的化感综合效应为抑制,油菜秸秆及紫云英+油菜为低促高抑;紫云英与油菜混合可作为改善紫云英、油菜单独使用效果的有效途径.%An experiment was conducted by indoor culture to study the allelopathic effects of straw and green manure on lettuce (Lactuca satiua L. ) germination and seedling growth. Results showed that straw and green manure extracts treatments could delay the progress of germination, even inhibit the germination rate at high concentration. In this study, low concentration of all extract treatments intensified the inhibit for seedling height, while for the root length they only expressed as normal inhibit. The fresh weight and dry weight reduced of lettuce seedlings increased as the concentration of extract treatments increased, then decreased afterwards. The extracts of rice straw, rape stalk, Chinese milk vetch and Chinese milk vetch mixed with rape stalk at different concentrations increased the seedling fresh weight by 27.33%, 27.52%, 1.28%, 19.24%, respectively. Under different concentrations, extracts of rice straw and Chinese milk vetch showed inhibit allelopathic effect on lettuce, while that of rape stalk and Chinese milk vetch mixed with rape stalk showed promotion allelopathic effect at low concentration. The mixture of Chinese milk vetch and rape stalk maybe an effective way to improve the effectiveness of Chinese milk vetch or rape stalk used alone.

  1. The Allelopathy of Plant Aqueous Extract of Oxalis corniculata to Radish and Lettuce%酢浆草(Oxalis corniculata)植株水浸提液对萝卜和生菜的化感效应

    Institute of Scientific and Technical Information of China (English)

    张志忠; 蒋云丹; 孙志浩; 蓝茂锋

    2012-01-01

    In order to explore the allelopathic effects of invasive plants Oxalis corniculata and its possible physiological mechanism, germination and seedling growth of radish and lettuce seeds and plant protection of enzyme activity were measured after treated with different concentrations plants aqueous extracts of Oxalis comiculata. Obvious allelopathic inhibition of plant aqueous extract of Oxalis comiculata to radish and lettuce was observed. Radish and lettuce seed germination and seedling growth were inhibited and.the degree of inhibition was enhanced with increase in plant aqueous extract concentration. This inhibition in radicle performance was stronger than hypocotyl. Different variation was observed in the activities of various protective enzymes of radish and lettuce seedling after treated with different concentrations plants aqueous extracts of Oxalis comiculata. POD and CAT activity continued to increase with increasing concentration; the low concentration of extract processing can be significantly enhanced CAT activity; POD activity continued to rise with increase in concentration; the activity of SOD did not show obvious regularity. MDA content continued to rise with increasing concentration.%通过采用不同浓度的酢浆草植株水浸提液处理萝卜和生菜种子与幼苗,测定其对不同受体材料种子发芽、幼苗生长和植株保护酶系统的影响,探讨酢浆草植株水浸提液对部分模式蔬菜植物的化感作用,推测其可能的生理机制.结果表明:酢浆草植株水浸提液对萝卜和生菜的种子萌发和幼苗生长表现出较为明显的化感抑制.酢浆草植株水浸提液处理后,萝卜和生菜的种子萌发、幼苗生长均被抑制,抑制程度随处理浓度增加而增强,对胚根的抑制强度大于胚轴.酢浆草植株水浸提液对幼苗各种保护酶活性的影响表现出不同的变化规律,POD和CAT的活性均随处理浓度的增加而持续上升,低浓度浸提液的处理即可显著增强CAT的活性;POD活性随处理浓度增加而均匀上升;SOD活性没有表现出明显的规律性;MDA含量均随酢浆草植株水浸提液浓度增加而持续升高.

  2. 喜马拉雅紫茉莉根水浸提液对五种植物的化感作用研究%Allelopathy of Water Extracts from Root ofMirabilis himalaica on Five Speices of Plants

    Institute of Scientific and Technical Information of China (English)

    马世尧; 刘胜利; 陈玉珍; 卢存福; 兰小中

    2015-01-01

    以采自西藏林芝地区的藏药植物喜马拉雅紫茉莉为试材,探讨其根部不同浓度(0.0125、0.025、0.05、0.1 g·mL-1)水浸提液对莴苣、绿豆、小麦、萝卜、油菜等5种植物的化感效应。结果表明,随着浸提液浓度的增加,受试植物的种子萌发及幼苗生长均受到不同程度的抑制,植株体内丙二醛含量持续升高,抗氧化酶活性及叶绿素含量逐渐下降,受试植物不同部位对浸提液敏感程度为地下部分>地上部分。另外,5种植物对浸提液敏感程度为莴苣>绿豆>小麦>萝卜>油菜。%To investigate the allelopathic effects ofMirabilis himalaicaroot,which was picked from Tibet Nyingchi region, on crop and vegetable plants, different concentrations (0.0125, 0.025, 0.05, 0.1 g·mL-1) of water extracts were used as treatment solutions to asses their effects on seed germination and seedling growth of five plant species (wheat, mung beans, lettuce, rape, and radish). The results showed that with the increase of the concentration of aqueous extract, the seed germination and seedling growth of the five plants were inhibited. Accordingly, antioxidant enzyme activity and chlorophyll content decreased, while the content of malondialdehyde was significantly increased. Allelopathic effects indicated that the underground part was more sensitive to theM. himalaica root water extracts than the aboveground part of the five plants. The results also conformed that allelopathic effects were species-specific and concentration- dependent. The sensitivity order was as follows: lettuce> mung beans>wheat> radish> rape.

  3. 分葱对黄瓜、萝卜和白菜的化感作用%Allelopathy of Allium fistulosum L.var.caespitosum Makino on Cucumis sativus L.,Raphanus sativus L. and Brassica chinensis L.

    Institute of Scientific and Technical Information of China (English)

    姜丽; 孙玉文; 刘景安

    2007-01-01

    以黄瓜(Cucumis sativus L.),萝卜(Raphanus satovis L.)和白菜(Brassica chinensis L.)3种蔬菜作物为受体,通过种子萌发试验及幼苗生长试验,对分葱(Allium fistulosum L.var.caespitosum Makino)根系及其地上部水浸液的化感作用进行了初步研究.结果表明:分葱根系和地上部水浸液对黄瓜、萝卜和白菜具有一定的化感作用.对黄瓜和萝卜的萌发有一定的抑制作用,而对其幼苗生长有一定的促进作用;对白菜的萌发表现为低浓度促进高浓度抑制,而对其幼苗生长有一定的抑制作用.因此,在蔬菜栽培制度中,分葱可与黄瓜和萝卜进行合理的轮作与间套作;但可能不适宜与白菜进行轮作或间套作.

  4. Alelopatia de Baccharis dracunculifolia DC. sobre a germinação e desenvolvimento de espécies cultivadas = Allelopathy of Baccharis dracunculifolia DC. on the germination and development of cultivated species

    Directory of Open Access Journals (Sweden)

    Grasielle Soares Gusman

    2008-04-01

    Full Text Available Metabótitos secundários produzidos em algumas plantas podem provocaralterações no desenvolvimento de outras plantas ou até mesmo de outros organismos. O objetivo deste trabalho foi identificar possíveis efeitos alelopáticos de extratos aquosos de folhas de Baccharis dracunculifolia na germinação e no crescimento de plântulas de Brassica campestris, B. oleracea cv. Capitata, Citrullus lanatus, Eruca sativa, Lactuca sativa cv. Branca Boston, L. sativa cv. Grand Rapids, L. sativa cv. Simpson, Lycopersicum esculentum, Raphanussativus e Zea mays L. Para a obtenção do extrato aquoso, foram utilizadas folhas previamente secas na concentração de 1 g 10 mL-1 (p/v e utilizadas sete concentrações deste extrato aquoso (100, 90, 70, 50, 30, 10 e 0%, em delineamento inteiramente casualizado, com cinco repetições de dez sementes das espécies cultivadas. Os extratos aquosos de B. dracunculifolia evidenciaram potencialidades alelopáticas sobre a germinação das sementes e no crescimento da parte aérea e do sistema radicular de todas espécies testadas, sendo que a redução na germinação e no crescimento inicial elevaram-se com o aumento das concentrações dos extratos aquosos utilizados. Os resultados indicam a existência de potencial alelopático de B. dracunculifolia.Secondary metabolites produced in some plant species can cause developmental changes in other plants or even in other organisms. Theobjective of this work was to identify the possible allelopathic effects of the aqueous extracts of Baccharis dracunculifolia leaves in the germination and growth of seedlings of Brassica campestris, B. oleracea cv. Capitata, Citrullus lanatus, Eruca sativa, Lactuca sativa cv. Branca Boston, L. sativa cv. Grand Rapids, L. sativa cv. Simpson, Lycopersicum esculentum, Raphanus sativus and Zea mays. The aqueous extracts were made out of dried leaves at 1g 10mL-1 (p/vconcentration and by using seven of those aqueous extract concentrations (100, 90, 70, 50, 30, 10 and 0%, arranged into a completely randomized design, with five repetitions of ten seeds of each cultivated species. The aqueous extracts of B. dracunculifolia revealed allelopathic potential in the germination of seeds and in the growth of the aerial part of the root system in all tested species, while the reduction in germination and initial growthintensified with the increase in the concentrations of the aqueous extracts used. The results indicate the existence of allelopathic potential in B. dracunculifolia.

  5. 小麦秸秆水浸提液对五种植物化感作用的研究%Allelopathy of wheat straw aqueous extract on five kinds of plants

    Institute of Scientific and Technical Information of China (English)

    郑曦; 杨茜茜; 李小花

    2016-01-01

    该文研究了不同浓度的小麦秸秆水浸提液对徐州地区2种玉米(郑单958和农大108)和3种常见玉米田间杂草(马唐、稗草和反枝苋)种子萌发和幼苗生长的影响。结果表明:当小麦秸秆浸提液浓度分别大于75、50和25 g•L-1时,马唐、稗草和反枝苋种子的萌发受到显著的抑制;当小麦秸秆浸提液浓度分别大于50和37.5 g•L-1时,玉米郑单958和农大108种子的萌发受到显著的抑制;但当小麦秸秆浸提液浓度大于37.5 g•L-1时,马唐、稗草和反枝苋幼苗根和芽的生长均受到明显的抑制;当小麦秸秆浸提液浓度小于75 g•L-1时,玉米郑单958和农大108幼苗根与芽的生长受到明显的促进,且郑单958幼苗叶片中叶绿素的含量以及郑单958的POD酶活性均得到提高。该研究结果表明较高浓度的小麦秸秆浸提液(50 g•L-1)会抑制杂草的生长,有利于玉米郑单958的生长,为小麦秸秆还田和玉米田杂草的生态防治提供了理论基础。%An experiment was carried out to explore effects of wheat straw aqueous extract on the seed germination and seedling growth of two kinds of maize ( Zhengdan 958 and Nongda 108) , large crabgrass ( Digitaria sanguinalis) , barn-yard grass (Echinochloa crusgalli) and redroot amaranth (Amaranthus retroflexus). The results showed that when the concentration of wheat straw aqueous extract was respective over 75, 50 and 37.5 g•L-1 , the seed germination rates of large crabgrass, barnyard grass and redroot amaranth were inhabited, while the concentration was over 50 and 37.5 g•L-1 , the seed germination rates of Zhengdan 958 and Nongda 108 were inhabited;but the root and shoot length of large crabgrass, barnyard grass and redroot amaranth decreased obviously when the extract concentration was over 37. 5 g•L-1;while the concentration of wheat straw aqueous extract was under 75 g•L-1 , the root and shoot length of these two kinds of maize were improved obviously, meanwhile the content of chlorophyll and the POD enzyme activity of maize ZD958 were enhanced, and the higher concentration of wheat straw aqueous extract (50 g•L-1) had an adverse impact on weeds growth, but it was good for the growth of maize Zhengdan 958.

  6. Alelopatia de extratos de diferentes órgãos de mulungu na germinação de alface Allelopathy of extracts of different organs of coral tree on the germination of lettuce

    Directory of Open Access Journals (Sweden)

    Andreya K Oliveira

    2012-09-01

    Full Text Available O mulungu (Erythrina velutina é uma árvore de crescimento rápido, com propriedades medicinais. O objetivo no presente trabalho foi avaliar o efeito alelopático do extrato aquoso de sementes, flores e cascas de mulungu na germinação e desenvolvimento de plântulas de alface cv. Mônica SF FI. O delineamento experimental utilizado foi inteiramente casualizado com sete tratamentos [extrato de sementes a 100°C, extrato de sementes a 25°C, extrato de cascas a 100°C, extrato de cascas a 25°C, extrato de flores a 100°C, extrato de flores a 25°C e água destilada (testemunha] com quatro repetições. Os extratos obtidos de sementes, independente da temperatura de extração reduziram a porcentagem e velocidade de germinação de sementes de alface e afetaram o desenvolvimento das plântulas. Os demais extratos não afetaram a germinação, mas causaram o aparecimento de plântulas anormais e mortas. Os extratos aquosos de sementes de mulungu têm potencial alelopático sobre as sementes de alface cv. Mônica SF FI.The coral tree (Erythrina velutina is a fast growing tree with medicinal properties. The aim of this study was to evaluate the allelopathic effects of aqueous extract of seeds, flowers and bark of coral tree on seed germination and seedling development of lettuce cv. Mônica SF FI. The experimental design was completely randomized with seven treatments [seed extract at 100°C, seed extract at 25°C, bark extract at 100°C, bark extract at 25°C, flower extract at 100°C, flower extract at 25°C and distilled water (control] with four replications. The extracts of seeds, independent of the extraction temperature decreased the percentage and speed of germination of lettuce and affected the development of the seedlings. The other extracts did not affect germination, but caused the appearance of abnormal seedlings and dead. The aqueous extract of seeds of coral tree has allelopathic potential in the seeds of lettuce cv. Mônica SF FI.

  7. Alelopatia de extratos voláteis na germinação de sementes e no comprimento da raiz de alface Allelopathy of plant volatile extracts on seed germination and radicle length of lettuce

    Directory of Open Access Journals (Sweden)

    Maria da Conceição Sampaio Alves

    2004-11-01

    Full Text Available O objetivo deste trabalho foi identificar possíveis efeitos alelopáticos de extratos voláteis de óleos essenciais na germinação e no comprimento da raiz de plântulas de alface. Foram utilizadas cinco concentrações de cada óleo (0,0, 0,001, 0,01, 0,1 e 1,0%, v/v, em delineamento inteiramente casualizado, com quatro repetições de 25 sementes de alface. Os extratos voláteis de óleos essenciais de canela, alecrim-pimenta, capim-citronela e alfavaca-cravo evidenciaram potencialidades alelopáticas na germinação e comprimento das raízes de plântulas de alface, efeitos que variaram de acordo com a concentração do óleo. O extrato volátil de óleo de jaborandi estimula o crescimento da radícula e não provoca inibição da germinação de sementes de alface, caracterizando-se como de efeito alelopático benéfico.The objective of this work was to identify allelopathic effects of volatile extracts of essential oils on germination and radicle length of lettuce seedlings. Five concentrations were utilized for each oil (0.0, 0.001, 0.01, 0.1 and 1.0%, v/v arranged into a completely randomized design with four replicates of 25 seeds. The volatile extracts of essential oils of cinnamon, alecrim-pimenta, capim-citronela and alfavaca-cravo revealed allelopathic potentialities on lettuce seed germination and radicle growth, effect which varied according to the oil concentration. The volatile extract of Jaborandi essential oil stimulates radicle growth and does not inhibit lettuce seeds germination, which is characterized as a beneficial allelopathic effect.

  8. Estudo fitoquímico de folhas de Solanum lycocarpum A. St.-Hil (Solanaceae e sua aplicação na alelopatia Phytochemistry of Solanum lycocarpum A.St.-Hil (Solanaceae leaves and their application in allelopathy

    Directory of Open Access Journals (Sweden)

    Sarah Christina Caldas Oliveira

    2012-09-01

    Full Text Available Solanum lycocarpum A.St.-Hil (Solanaceae é um arbusto típico da região central do Brasil (Cerrado. A atividade alelopática do extrato aquoso de folhas e frutos dessa espécie já foi verificada em estudos anteriores. O objetivo desse trabalho foi avaliar a atividade alelopática de diferentes extratos de S. lycocarpum na germinação e crescimento de quatro espécies-alvo. As folhas foram coletadas, secas e trituradas e submetidas a dois métodos distintos de extração: 1- líquido-líquido (acetato de etila e diclorometano do extrato aquoso das folhas e 2- com solventes em polaridade crescente (hexano, diclorometano, acetato de etila, acetona, metanol e água diretamente das folhas. Cada extração foi realizada com equipamento de ultrassom durante uma hora, filtrado e evaporado. Desses extratos, soluções de 800, 400 e 200 ppm foram preparadas, e água e Logran® foram usados como controle positivo e negativo, respectivamente. Cada solução, bem como os controles, foi dissolvida em DMSO para os bioensaios. As espécies alvo usadas foram: alface, agrião, tomate e cebola. Cada placa era composta de 20 sementes e foi adicionado 1 mL de solução teste com 4 repetições. As placas foram incubadas a 25 ºC no escuro. Posteriormente, as plântulas tiveram suas partes aéreas e raízes medidas e a porcentagem de germinação e inibição calculada para cada extrato. Tomate foi a espécie que mostrou maior sensibilidade para todos os extratos, seguido de agrião, cebola e alface. Os extratos que tiveram maior atividade foram o acetato de etila, acetona e as extrações líquido-líquido, indicando as frações que devem conter os princípios ativos da folha dessa espécie.Solanum lycocarpum A.St.-Hil (Solanaceae is a typical shrub in the Cerrado of central Brazil. The allelopathic activity of aqueous extracts of the leaves and fruits of this species has already been proven in previous studies. The goal of this work was to verify the allelopathic activity of different leaf extracts of S. lycocarpum on the germination and growth of four target species. The leaves were collected, dried, triturated and submitted to two distinct methods of extraction: 1- liquid-liquid (ethyl acetate and dichloromethane from the aqueous extract and 2- with solvents of increasing polarities (hexane, dichloromethane, ethyl acetate, acetone, methanol and water directly from the leaves. Each extraction was made with ultrasound equipment for one hour, filtered and evaporated. From these extracts, solutions of 800, 400 and 200 ppm were prepared, and water and Logran® were used as positive and negative controls, respectively. Each solution, as well as the controls, was dissolved in DMSO for the bioassays. The target species used were lettuce, watercress, tomato and onion. To each plate, 20 seeds were added and 1 mL of the tested solutions (with 4 repetitions. The plates were incubated at 25 ºC without light, and the shoots and roots of the seedlings were then measured and the percentage of germination and the inhibition of each extract were calculated. Tomato was the most sensitive to the extracts, followed by watercress, onion and lettuce. The extracts with stronger activity were AcOEt, acetone and the liquid-liquid extraction, indicating the fractions that may contain the active principles of the leaves in this species.

  9. 穿心莲连作土壤提取物对其种子的化感作用%Allelopathy of Continuously Cropped Soil Extracts on Andrographis paniculata Seed Germination

    Institute of Scientific and Technical Information of China (English)

    李俊仁; 陈秀珍; 刘凯频; 彭秋菊; 詹若挺; 何瑞

    2016-01-01

    [目的]考察不同质量浓度穿心莲连作土壤提取物对其种子的化感作用.[方法]制备连作0年、连作1年及连作2年的穿心莲栽培土壤水、醇提取物,稀释至不同试验浓度用于穿心莲种子发芽试验.[结果]穿心莲连作土壤的水提物及醇提物均对穿心莲种子的发芽指数、发芽势、发芽率及胚根长有不同程度的抑制作用,但其抑制作用与连作年限无明显关联,3个连作年限土壤的抑制效果比较,差异均无统计学意义(P>0.05).水提物中,以125 mg/mL的抑制效果最强.醇提物中,高浓度醇提物的抑制作用较强,尤以抑制胚根长度的作用最为明显.在水提物和醇提物作用下,穿心莲种子各萌发指标的化感效应指数(RI)均RI<0,并且化感综合效应(SE)也均SE<0.[结论]穿心莲连作土壤提取物对其种子萌发存在化感抑制作用,化感作用可能是造成穿心莲连作障碍的原因之一.

  10. 孔雀草、盐肤木对紫花苜蓿的化感效应研究%The Allelopathy Research on Medicago Sativa Resulting from Tagetes patula and Rhus chinensis

    Institute of Scientific and Technical Information of China (English)

    魏科梁; 夏振尧; 夏栋; 戴方喜

    2012-01-01

    通过种子萌发和幼苗生长试验,研究了孔雀草、盐肤木2种植物的叶、茎、根水浸提液对紫花苜蓿的化感作用,结果表明:孔雀草、盐肤木不同部位的水浸提液对紫花苜蓿的种子萌发和幼苗生长均有抑制作用,且浓度越大作用越明显.说明紫花苜蓿和孔雀草不宜混播;盐肤木作为灌木和紫花苜蓿混植,只要种植密度适当,是可行的.可为生态护坡的植物选择提供参考.

  11. Research on allelopathy of aqueous extract from Tagetes patula to four garden plants%孔雀草水浸提液对4种园林植物化感作用的研究

    Institute of Scientific and Technical Information of China (English)

    黄玉梅; 张杨雪; 刘庆林; 黄胜岚; 刘盼

    2015-01-01

    以4种园林植物石竹、千叶蓍、二月兰、鸡冠花作为受体,采用室内培养皿法,研究了不同浓度孔雀草水浸提液(0,12.5,25.0,50.0,100.0 mg/mL)对4种园林植物种子萌发及幼苗生长的化感作用,旨在为孔雀草在园林植物配置中的应用提供科学依据。结果表明,孔雀草水浸提液对4种园林植物种子萌发及生长有明显影响,且4种园林植物间存在一定差异。孔雀草水浸提液对石竹、二月兰、鸡冠花种子萌发均表现为抑制作用,对千叶蓍种子则表现为一定的促进作用;孔雀草水浸提液对石竹幼苗表现为抑制作用,而对二月兰和鸡冠花幼苗表现为“低促高抑”,浓度为100.0 mg/mL 时,抑制作用最强;千叶蓍幼苗生长在浸提液浓度为50.0 mg/mL 时仍表现为显著的促进作用,仅在100.0 mg/mL 时受到一定程度抑制;孔雀草水浸提液对石竹、鸡冠花和二月兰幼苗叶绿素含量基本都表现为抑制作用,千叶蓍仅在100.0 mg/mL 时表现为抑制;二月兰、鸡冠花幼苗 POD 活性在中低浓度时有不同程度升高,100.0 mg/mL 时呈下降趋势,石竹幼苗 POD 活性随浸提液浓度升高持续下降,千叶蓍则先下降后升高;石竹和鸡冠花幼苗 MDA 含量随浸提液浓度升高而升高,千叶蓍和二月兰则先下降后升高。%In order to provide scientific theoretical basis for the application of Tagetes patula in the garden plants configuration,the aqueous extracts from Tagetes patula was used to search the allelopathic effects on seed germination and seedling growth of Dianthus chinensis ,Achillea millefolium ,Orychophragmus viola-ceus ,Celosia cristata using petridishs with filter papers.Results showed that the aqueous extracts from Tagetes patula had significant allelopathic effects on seed germination and seedling growth of four garden plants.The aqueous extracts from Tagetes patula inhibited seed germination of D .chinensis ,O.violaceus and C.cristata,on the contrary,inceased seed germination of A.millefolium in a degree.The extracts also inhibi-ted seedling growth of D .chinensis at all concentrations,but promoted at the lower concentrations and inhibi-ted at the higher ones the seedling growth of O.violaceus and C.cristata.The inhibition was the most inten-sive by treatment with 100.0 mg/mL of the aqueous extracts.Whereas,the growth of A.millefolium was pro-moted significantly at 12.5,25.0,50.0 mg/mL,and inhibited only by treatment with 100.0 mg/mL.The chlorophyll content in these four garden plants were reduced by 23.46%,42.56%,14.75% and 58.28%, when the aqueous extracts concentration was 100.0 mg/mL.The extracts increased the activities of peroxidase(POD)of O.violaceus and C.cristata at the lower concentration,while decreased the activities of POD at 100.0 mg/mL.The activity of POD of D .chinensis declined at all concentrations,while A.millefolium de-clined earlier then ascended later.The content of MDA of D .chinensis and C.cristata ascended at all concen-trations,whereas A.millefolium and O.violaceus declined earlier then ascended later.It implied that T.pat-ula had different allelopathic effects on different garden plants and “concentration effect”was found in this research.

  12. Allelopathy of Extracted Solutions from Flax, Castor and Hemp on Soybean Cyst Nematode%亚麻、蓖麻和大麻浸提液对 SCN化感作用的研究

    Institute of Scientific and Technical Information of China (English)

    刘淑霞; 潘冬梅; 魏国江; 杜春玉; 高宇; 韩喜财; 姜颖

    2014-01-01

    The killing effect of extracted solutions from different tissues and organs in flax , castor and hemp acting on soybean cyst nematode was studied in this paper , the result showed that the extracted solution from flax root had a stimulatory function to the hatch of cysts and was most capable of killing the juveniles.The killing effect of the extracted solution from hemp leaves was better than that from roots.%利用亚麻、蓖麻和大麻三种植物不同器官浸提液对SCN卵和J2的室内毒力进行了测定,结果表明亚麻根提取物显著促进胞囊孵化,且对SCN J2毒杀效果最好;同一植物根提取物对SCN J 2毒杀效果随着浓度的增大而增强。

  13. 杂草科学管理——理论基础与实施途径%Scientific Management of Weed:Theory and Implementation

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    涂修亮; 陈英明

    2002-01-01

    Scientific management of weeds is theoretically based on ecology.The implementation methods inclade:Intensifying the weed biology and ecology research, especially those of the heavy weeds;Intensifying the research of developing competition between the crop and the weed;Utilizing a allelopathy the gene engineering and breeding against the weeds;Utilizing allelopathy between the crop and the weed, and utilizing biological and agricultural measurements to control the weeds.

  14. 玉米秸秆腐解液中酚酸的检测及对小麦土传病原菌的化感作用%Determination of Phenolic Acids in Decomposing Products of Maize Straw and their Allelopathy on Pathogens of Wheat Soil-borne Disease

    Institute of Scientific and Technical Information of China (English)

    梁春启; 甄文超; 张承胤; 尹宝重

    2009-01-01

    在不同时期提取玉米秸秆腐解液,利用高效液相色谱检测其中酚酸类物质及其含量,并测定检测到的不同酚酸类物质对小麦土传病原菌孢子萌发和茵丝生长的影响率.结果表明,在玉米秸秆腐解液中共检测到5种酚酸类物质.不同时期提取的腐解液中酚酸类物质的种类和含量有所不同,其中在同期腐解液中邻苯二甲酸和苯甲酸含量明显高于其它3种酚酸:5种酚酸类物质对3种病原茵的茵丝生长及对禾顶囊壳小麦变种(Gaeumannomyces graminis var.tritici)和平脐蠕孢茵(Bipolaris sorokiniana(Sacc.)Shoem.)的孢子萌发具有不同程度的促进或抑制作用,且随着浓度的增高而作用趋势增强.

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

    Institute of Scientific and Technical Information of China (English)

    熊勇; 屈睿; 王红斌; 熊开金; 姜传亮

    2011-01-01

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

  16. Allelopathy effects of leaf water extracts from an invasive species Leucaena leucocephala on the seed germinations of three brassicaceae vegetable species%银合欢叶片水提液对3种蔬菜种子萌发的化感效应

    Institute of Scientific and Technical Information of China (English)

    陶文琴; 林佳如; 郭艳霞; 黄丽宜; 缪绅裕; 王厚麟; 黎延阳; 宋健新

    2013-01-01

    研究外来入侵植物银合欢(Leucaena leucocephala)叶片的化感作用,为揭示潜在的生态危害提供参考.配置不同浓度的银合欢叶水提液处理3种十字花科蔬菜种子,按生物测定方法及公式计算其化感指数和综合效应.结果显示,随着银合欢叶水提液浓度的增加,对芥菜(Brassicajuncea)、菜心(B.parachinensis)和白菜(B.pekinensis)种子萌发和根长生长的抑制作用增强,且抑制作用大小整体表现为芥菜>菜心>白菜;不同浓度叶水提液对不同受体植物幼苗茎长生长的影响情况较复杂.综合效应指数表明,银合欢叶对3种十字花科蔬菜作物种子萌发均有较明显的化感作用.结果提示,银合欢作为外来入侵植物,因具较强的化感效应,需加强防治.

  17. 海洋底栖甲藻——利玛原甲藻(Prorocentrum lima)对三种赤潮藻的化感作用%Allelopathy of marine benthic dinoflagellate-Prorocentrum lima on three red tide algae

    Institute of Scientific and Technical Information of China (English)

    杨维东; 李丽璇; 刘洁生; 张剑军

    2008-01-01

    为明确利玛原甲藻(Prorocentrum lima)对其它生物可能存在的化感作用,考察了利玛原甲藻培养物、无藻细胞滤液以及腹泻性贝类毒素(diarrhetic shellfish poisoning,DSP)租提物对塔玛亚历山大藻(Alexandrium tamarense)、海洋卡盾藻(Chauondla marina)和东海原甲藻(Prorocentrum donghaiense)3种赤潮藻生长的影响.结果显示,共培养时利玛原甲藻对其它3种赤潮藻的生长有不同程度的抑制作用,其生长也受到3种赤潮藻的影响;无藻细胞滤液对东海原甲藻和海洋卡盾藻有抑制作用,其中对东海原甲藻的抑制作用更明显.但对塔玛亚历山大藻的影响不大;比较而言,DSP粗提物对3种藻的影响最为明显,甚至可完全抑制海洋卡盾藻的生长.这些结果提示.利玛原甲藻与赤潮藻间存在交互抑制作用,可能会通过分泌化感物质、细胞间接触抑制等途径抑制其它藻的生长;利玛原甲藻具有一定的化感作用,但DSP毒索并非利玛原甲藻发挥化感效应的主要原因.

  18. Effects of allelopathy of Ulva pertusa Kjellm on growth and antioxidant enzymatic activies of Heterosigma akashiwo (Hada) Hada%孔石莼克生作用对赤潮异弯藻生长和抗氧化系统活性的影响

    Institute of Scientific and Technical Information of China (English)

    蔡恒江; 李博; 孙禾琳

    2010-01-01

    通过实验生态学和生物化学的方法,研究了孔石莼(Ulva pertusa Kjellman)克生作用对赤潮异弯藻[Heterosigma akashiwo(nada)Hada]生长及其叶绿素a(Chl-a)含量、可溶性蛋白含量、丙二醛(MDA)含量、总抗氧化能力(T-AOC)、过氧化氢酶(CAT)活力、超氧化物歧化酶(SOD)活力和谷胱甘肽过氧化酶(GPX)活力的影响.结果表明:孔石莼的克生作用会明显抑制赤潮异弯藻的生长,且赤潮异弯藻抗氧化系统活性对其有明显的响应.克生作用会使T-AOC和SOD活力呈现降低的趋势;MDA含量和CAT活力呈现升高的趋势;GPX活力呈现先升高而后下降趋势;Chl-a含量和可溶性蛋白含量并无明显变化.推测孔石莼克生作用诱导赤潮异弯藻产生活性氧自由基,是藻体受损伤的主要原因.

  19. Alelopatia de Baccharis dracunculifolia DC. sobre a germinação e desenvolvimento de espécies cultivadas - DOI: 10.4025/actascibiolsci.v30i2.3592 Allelopathy of Baccharis dracunculifolia DC. on the germination and development of cultivated species - DOI: 10.4025/actascibiolsci.v30i3.3592

    Directory of Open Access Journals (Sweden)

    Alexandre Horácio Couto Bittencourt

    2008-05-01

    Full Text Available Metabótitos secundários produzidos em algumas plantas podem provocar alterações no desenvolvimento de outras plantas ou até mesmo de outros organismos. O objetivo deste trabalho foi identificar possíveis efeitos alelopáticos de extratos aquosos de folhas de Baccharis dracunculifolia na germinação e no crescimento de plântulas de Brassica campestris, B. oleracea cv. Capitata, Citrullus lanatus, Eruca sativa, Lactuca sativa cv. Branca Boston, L. sativa cv. Grand Rapids, L. sativa cv. Simpson, Lycopersicum esculentum, Raphanus sativus e Zea mays L. Para a obtenção do extrato aquoso, foram utilizadas folhas previamente secas na concentração de 1 g 10 mL-1 (p/v e utilizadas sete concentrações deste extrato aquoso (100, 90, 70, 50, 30, 10 e 0%, em delineamento inteiramente casualizado, com cinco repetições de dez sementes das espécies cultivadas. Os extratos aquosos de B. dracunculifolia evidenciaram potencialidades alelopáticas sobre a germinação das sementes e no crescimento da parte aérea e do sistema radicular de todas espécies testadas, sendo que a redução na germinação e no crescimento inicial elevaram-se com o aumento das concentrações dos extratos aquosos utilizados. Os resultados indicam a existência de potencial alelopático de B. dracunculifolia.Secondary metabolites produced in some plant species can provoke development changes in other plants or even in other organisms. The objective of this work was to identify the possible allelopathic effects of the aqueous extracts of Baccharis dracunculifolia leaves in the germination and growth of Brassica campestris, B. oleracea cv. Capitata, Citrullus lanatus, Eruca sativa, Lactuca sativa cv. Branca Boston, L. sativa cv. Grand Rapids, L. sativa cv. Simpson, Lycopersicum esculentum, Raphanus sativus and Zea mays seedlings. The aqueous extracts were made out of dried leaves at a 1g 10 mL-1 (p/v concentration and by using seven of those aqueous extract concentrations (100, 90, 70, 50, 30, 10 and 0%, arranged into a completely randomized design, with five repetitions of ten seeds of each cultivated species. The aqueous extracts of B. dracunculifolia revealed allelopathic potentialities on the germination of the seeds and in the growth of the aerial part of the root system in all tested species and the reduction in the germination and in the initial growth increased with the increase of the concentrations of the used aqueous extracts. The results indicate the existence of allelopathic potential in B. dracunculifolia.

  20. Potenciação alelopática de extratos vegetais na germinação e no crescimento inicial de picão-preto e alface Allelopathy of plant extracts on germination and initial growth of beggartick (Bidens pilosa L. and lettuce (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    Magda Cristiani Ferreira

    2007-08-01

    Full Text Available O picão-preto (Bidens pilosa L. é uma planta daninha muito agressiva, que está presente em quase todo Brasil. O principal método de controle é o químico, porém apresenta elevado impacto ambiental, risco de intoxicação humana e possibilidade de causar fitotoxicidade as culturas. O objetivo do trabalho foi avaliar o efeito alelopático de extratos etanólicos de Eucalyptus citriodora Hook. e Pinus elliottii L. na germinação e no crescimento inicial de picão-preto e alface (Lactuca sativa L.. Foram testadas quatro concentrações de cada extrato (0,25; 0,50; 1,0 e 2,0 % além do controle (0,0 % água destilada com Tween 20 a 0,08 %. O delineamento experimental foi o inteiramente casualizado, com quatro repetições em condições de laboratório. O extrato de P. elliottii não causou efeito alelopático sobre o picão-preto e o alface. O extrato de E. citriodora reduziu significativamente o índice de velocidade de germinação (IVG do picão-preto em todas as concentrações testadas quando comparadas com o controle (0,0%, porém para a alface o IVG foi significativo apenas na concentração de 2,0 %. Para o comprimento da raiz não foi possível observar diferença significativa entre os tratamentos para os dois extratos testados tanto para o alface como para o picão preto.Bidens pilosa L. is an aggressive weed found all over Brazil. The main control method for this species is chemical treatment however, causes strong environmental impact, and it has great human contamination risks, and may cause phytotoxity to crops. The objective of this study was to evaluate the effect of ethanolic extracts of Eucalyptus citriodora Hook. and Pinus elliottii L. on seed germination and initial growth of B. pilosa and lettuce (Lactuca sativa L.. Five concentrations of each extract (0.0; 0.25; 0.50; 1.0; 2.0% were tested in laboratory conditions using a randomized complete block design with four replicates. P. elliottii extract had no effect on B. pilosa and lettuce. However, E. citriodora extract, significantly reduced germination index (GI of B. pilosa, in all tested concentrations, when compared with the control composed by distilled water. Lettuce GI was affected only by 2,0% concentration of ethanolic extract. Extracts of both P. elliottii and E. citriodora had no significant effect on the root length parameter of both B. pilosa and lettuce.

  1. Variação sazonal na alelopatia de extratos aquosos de Coleus barbatus (A. Benth. sobre a germinação e o desenvolvimento de Lactuca sativa L. Seasonal variation in the allelopathy of aqueous extracts from Coleus barbatus (A. Benth. on the germination and development of Lactuca sativa L.

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    L.L. Pelegrini

    2012-01-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito alelopático de extratos de Coleus barbatus sobre a germinação e desenvolvimento de plântulas de alface. Os experimentos foram conduzidos em laboratório, em diferentes concentrações de extratos obtidos de folhas de falso-boldo (0; 7,5; 15; 22,5; 30%, coletadas nas quatro estações do ano, obtidos por trituração, maceração, infusão e decocção. As sementes de alface foram distribuídas sobre placas de petri umidecidas com 10 mL de solução. Os resultados mostraram que os extratos de folhas afetaram a germinabilidade de sementes de alface apenas na concentração de 30% do extrato preparado por decocção de folhas coletadas no inverno. O índice de velocidade de germinação apresentou redução significativa nos extratos triturados preparados no outono e inverno; na maceração de folhas coletadas no verão e outono e no extrato de decocção preparado no inverno. Os extratos estimularam o crescimento da parte aérea das plântulas de alface, ao passo que, o comprimento das raízes foi afetado pelos extratos, ora inibindo, ora estimulando o crescimento das mesmas. Os extratos de folhas de falso-boldo coletadas nas quatro estações do ano apresentaram efeito alelopático sobre a germinação e o desenvolvimento da alface, sendo que estes variaram em função da sazonalidade da coleta, da forma de obtenção dos extratos e das concentrações testadas.The aim of this study was to evaluate the allelopathic effects of extracts from Coleus barbatus on germination and seedling growth of lettuce. The experiments were conducted in the laboratory using different concentrations (0, 7.5, 15, 22.5, 30% of aqueous extracts from "falso-boldo" leaves harvested in all four seasons; extracts were obtained by grinding, maceration, infusion and decoction. Seeds were distributed on Petri dishes moistened with 10 mL solution. Results showed that the leaf extracts affected the germination of lettuce seeds only at the concentration of 30% extract prepared by decoction of leaves harvested in the winter. Germination speed index showed significant reduction for ground extracts prepared in the fall and winter, as well as for macerated leaves harvested in the summer and fall and for extracts prepared through decoction in the winter. The extracts stimulated the growth of shoots of lettuce seedlings, whereas root length was affected by the extracts, which either stimulated or inhibited its growth. Extracts of "falso-boldo" leaves harvested in all four seasons had allelopathic effect on germination and development of lettuce, and the latter varied depending on the harvest season, the form of preparing the extracts and the tested concentrations.

  2. Alelopatia do extrato aquoso e do óleo essencial de folhas do manjericão "Maria Bonita" na germinação de alface, tomate e melissa Allelopathy of aqueous extract and essential oil of leaves from basil "Maria Bonita" on lettuce, tomato and melissa germination

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    L.D.S. Rosado

    2009-01-01

    Full Text Available O objetivo deste trabalho foi estudar o efeito alelopático do extrato aquoso e do óleo essencial de folhas frescas de Ocimum basilicum L. 'Maria Bonita' no índice de velocidade de germinação, comprimento de raízes e porcentagem de germinação da alface (Lactuca sativa L., de tomate (Lycopersicum esculentum Mill., e de melissa (Melissa officinalis L.. Os extratos foram obtidos pela trituração das folhas frescas e o óleo essencial extraído por hidrodestilação das folhas durante 90 min. Foram utilizadas duas formas de aplicação, extrato aquoso e óleo essencial, cinco concentrações (0,0; 0,001; 0,01; 0,1 e 1,0% v/v, em delineamento inteiramente casualizado, com cinco repetições, com 25 sementes de cada espécie por placa, totalizando 25 parcelas para cada espécie. Através dos resultados obtidos pode-se concluir que os extratos aquosos de manjericão apresentaram efeito significativo apenas para o índice de velocidade de germinação das sementes de tomate e para comprimento de raízes da alface e da melissa. O óleo essencial do manjericão apresentou potencialidades alelopáticas inibitórias em sementes de alface, de tomate e de melissa afetando o índice de velocidade de germinação, o comprimento das raízes e a porcentagem de germinação.The aim of this work was to study the allelopathic effect of aqueous extract and essential oil of fresh leaves from Ocimum basilicum L. 'Maria Bonita' on germination velocity index, root length and germination percentage of lettuce (Lactuca sativa L., tomato (Lycopersicum esculentum Mill., and melissa (Melissa officinalis L.. The extracts were obtained by grounding fresh leaves and the essential oil was extracted through hydrodistillation of the leaves during 90 min. Two application forms were used, aqueous extract and essential oil, five concentrations (0.0; 0.001; 0.01; 0.1 and 1.0% v/v, in completely randomized design, with five replicates including 25 seeds of each species per plot, totaling 25 plots for each species. The obtained results indicated that the aqueous extracts of basil presented a significant effect only for the germination velocity index of tomato seeds, as well as for lettuce and melissa root length. Basil essential oil presented allelopathic inhibitory potential in lettuce, tomato and melissa seeds, affecting germination velocity index, germination percentage and seedling root length.

  3. ESTUDIO DE PREFORMULACIÓN PARA EL DESARROLLO DE UN GEL A BASE DE POLÍMEROS CON CAPACIDAD MUCOADHESIVA PARA ENSAYOS DE ALELOPATÍA EN INVERTEBRADOS MARINOS. Preformulation study for the development of a polymer-based gel with mucoadhesive propierties for its use in allelopathy assays in marine invertebrates

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    Jenny Patricia Andrade

    Full Text Available La investigación se desarrolló con el fin de implementar una metodología que permitiera la realización de ensayos de interacciones alelopáticas entre corales y esponjas, minimizando la interacción física provocada por el uso de dispositivos que producen roce y efecto abrasivo sobre los pólipos del coral. Se llevó a cabo un estudio de preformulación utilizando polímeros con características mucoadhesivas sobre mucus que recubre los pólipos de coral, con el fin de obtener un gel, incorporando en las formulaciones un extracto de la esponja Cliona delitrix. Se caracterizaron propiedades como extensibilidad y adherencia, así como la capacidad bioadhesiva de las formulaciones propuestas, considerando su comportamiento reológico. Estas mostraron una buena estabilidad física frente a las condiciones del medio marino tanto in vitro como in situ. De igual manera, se diseñó un dispositivo que facilitó la aplicación del gel sobre la superficie de los corales por parte de los buzos en el arrecife coralino. Finalmente se estudió el comportamiento de liberación al medio acuoso simulado del gel con el extracto de la esponja objeto de estudioThis study was carried out with the purpose of implementing a methodology to assess allelopathic interactions assays between corals and reef sponges reducing the physical interaction caused by the use of devices that involve abrasion and harm over the coral polyps. Was carried out a preformulation study using polymers with mucoadhesive on the mucus that cover the coral polyps, with the purpose of develop a gel, incorporating an extract from Cliona Delitrix into the formulations. Obtained formulations were characterized by properties such as extensibility, adherence and mucoadhesive capacity. These formulations showed great physical stability under prevalent marine conditions both in vitro and in situ. In the same way was designed a device that let the smearing of the gel over the coral surfaces carried out for the divers in the coral reefs. Finally, was studied the releasing behavior of the gel with the sponge´s extract into the sea water conditions

  4. Phyto chemical study and evaluation of allelopathy in Memora peregrina, 'ciganinha', Bignoniaceae, an invading species in pastures in Mato Grosso do Sul, Brazil; Estudo fitoquimico e avaliacao alelopatica de Memora peregrina - 'ciganinha' - Bignoniaceae, uma especie invasora de pastagens em Mato Grosso do Sul

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    Grassi, Rafaela Ferreira [Mato Grosso do Sul Univ., Campo Grande, MS (Brazil). Dept. de Quimica; Resende, Ubirazilda Maria [Mato Grosso do Sul Univ., Campo Grande, MS (Brazil). Dept. de Biologia; Silva, Walciane da; Macedo, Maria Ligia Rodrigues [Mato Grosso do Sul Univ., Campo Grande, MS (Brazil). Dept. de Ciencias Naturais; Butera, Ana Paola; Tulli, Elayne de Oliveira; Saffran, Francis Paes; Siqueira, Joao Maximo de [Mato Grosso do Sul Univ., Campo Grande, MS (Brazil). Dept. de Farmacia-Bioquamica]. E-mail: jmaximo@nin.ufms.br

    2005-04-01

    Memora peregrina (local name: 'ciganinha' - Bignoniaceae) is a weed that often invades pastures in the Brazilian state of Mato Grosso do Sul. From its leaves and subterranean parts, the following compounds were isolated: allantoin (20.7 w/w in subterranean parts), the iridoid 6{beta}-hydroxyipolamiide, hyperin, 3'-O-methylhyperin, 4-hydroxy-N-methylproline, {beta}-sitosterol, {alpha}-amirin and {beta}-amirin, and lupeol. Allantoin exhibited an activity of inducing germination in seeds of Lactuca sativa used as a biological model, and the iridoid showed moderate activity in the larval development of Anagasta kuehniella. These results, associated with this plant's behavior, are suggestive of the occurrence of adaptive and competitive strategies in relation to other plant species. (author)

  5. Estudo fitoquímico e avaliação alelopática de Memora peregrina - "ciganinha" - Bignoniaceae, uma espécie invasora de pastagens em Mato Grosso do Sul Phytochemical study and evaluation of allelopathy in Memora peregrina, 'ciganinha', Bignoniaceae, an invading species in pastures in Mato Grosso do Sul, Brazil

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    Rafaela Ferreira Grassi

    2005-03-01

    Full Text Available Memora peregrina (local name: 'ciganinha' - Bignoniaceae is a weed that often invades pastures in the Brazilian state of Mato Grosso do Sul. From its leaves and subterranean parts, the following compounds were isolated: allantoin (20.7 w/w in subterranean parts, the iridoid 6beta-hydroxyipolamiide, hyperin, 3'-O-methylhyperin, 4-hydroxy-N-methylproline, beta-sitosterol, alpha-amirin and beta-amirin, and lupeol. Allantoin exhibited an activity of inducing germination in seeds of Lactuca sativa used as a biological model, and the iridoid showed moderate activity in the larval development of Anagasta kuehniella. These results, associated with this plant's behavior, are suggestive of the occurrence of adaptive and competitive strategies in relation to other plant species.

  6. 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.

  7. Ecological Effects of Allelopathic Plants

    DEFF Research Database (Denmark)

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

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

  8. EPCOT, NASA and plant pathogens in space.

    Science.gov (United States)

    White, R

    1996-01-01

    Cooperative work between NASA and Walt Disney World's EPCOT Land Pavilion is described. Joint efforts include research about allelopathy in multi-species plant cropping in CELSS, LEDs as light sources in hydroponic systems, and the growth of plant pathogens in space.

  9. Chemical warfare in freshwater

    NARCIS (Netherlands)

    Mulderij, Gabi

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field expe

  10. Impact of kenaf extracts on germination of green bean, tomato, cucumber, and Italian ryegrass

    Science.gov (United States)

    The chemical interaction between plants, referred to as allelopathy, may result in the inhibition of plant growth and development. The objective of this research was to determine the impact of kenaf (Hibiscus cannabinus L.) plant extracts on the seed germination of five plant species. Four concentra...

  11. Methanol production from eucalyptus wood chips. Attachment VI. Florida's eucalyptus energy farm: the natural system interface

    Energy Technology Data Exchange (ETDEWEB)

    Fishkind, H.H.

    1982-05-01

    A review of pertinent literature covered the following: eucalypt background, the candidate species, biomass plantation considerations, effects of site production, leachate and allelopathy, and some exotic flora considerations. The comparative eucalypt field survey covers mined land stands, unmined south Florida stands, and Glade County eucalypt stands. The problem of eucalypt naturalization is discussed.

  12. Impact of kenaf (Hibiscus cannabinus L.) leaf, bark, and core extracts on germination of five plant species

    Science.gov (United States)

    The chemical interaction between plants, which is referred to as allelopathy, may result in the inhibition of plant growth and development. The objective of this research was to determine the impact of kenaf (Hibiscus cannabinus L.) plant extracts on the germination and post-germination development ...

  13. 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.

  14. Kenaf’s allelopathic impact on seedling growth

    Science.gov (United States)

    Allelopathy is the chemical interaction between plants, which may result in the inhibition of plant growth and development. Research was conducted to determine the impact of kenaf (Hibiscus cannabinus L.) plant extracts on the post-germination growth of five plant species. Four concentrations (0, 16...

  15. Allelopathic influence of a wheat or rye cover crop on growth and yield of no-till cotton

    Science.gov (United States)

    TECHNICAL ABSTRACT No-till planting cotton into small grain cover crops has many benefits including reducing soil erosion and allelopathic suppression of weeds. It is suggested that the potentials of allelopathy on cotton plants. Nevertheless, little is known about the actual effects of alleloche...

  16. Growth inhibition and colony formation in the cyanobacterium Microcystis aeruginosa induced by the cyanobacterium Cylindrospermopsis raciborskii

    NARCIS (Netherlands)

    Mello, M.M.; Soares, M.C.S.; Roland, F.; Lürling, M.F.L.L.W.

    2012-01-01

    In a tropical reservoir, the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii are the dominant species, with changes in dominance throughout the year. Since allelopathy has been suggested as a factor that could promote or stabilize harmful algal blooms, we investigated potenti

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

    Science.gov (United States)

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

    2013-07-01

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

  18. Kenaf (Hibiscus cannabinus L.) impact on post-germination seedling growth

    Science.gov (United States)

    The chemical interaction between plants, which is referred to as allelopathy, may result in the inhibition of plant growth and development. The objective of this research was to determine the impact of kenaf (Hibiscus cannabinus L.) plant extracts on the post-germination growth of five plant species...

  19. 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...

  20. Chemical warfare in freshwater. Allelpathic effects of macrophytes on phytoplankton

    NARCIS (Netherlands)

    Mulderij, G.

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field expe

  1. Searching for allelopathic effects of submerged macrophytes on phytoplankton-state of the art and open questions

    NARCIS (Netherlands)

    Gross, E.M.; Hilt (nee Körner), S.; Lombardo, P.; Mulderij, G.

    2007-01-01

    Allelopathy, here defined as biochemical interactions between aquatic primary producers, has always been intriguing as a process explaining the dominance of certain plant or algal species over others. Negative chemical interference has been invoked as one of the steering mechanisms behind mutual dom

  2. Cover crop-based ecological weed management: exploration and optimization

    NARCIS (Netherlands)

    Kruidhof, H.M.

    2008-01-01

    Keywords: organic farming, ecologically-based weed management, cover crops, green manure, allelopathy, Secale cereale, Brassica napus, Medicago sativa Cover crop-based ecological weed management: exploration and optimization. In organic farming systems, weed control is recognized as one of the mai

  3. Herinplantziekte en groeiproblemen in zomerbloemen

    OpenAIRE

    Slootweg, G.; Breeuwsma, S.J.; Helm, van der, F.P.M.

    2010-01-01

    In een bijeenkomst met kwekers en voorlichters zijn herinplantproblemen in de praktijk geïnventariseerd. Aangegeven werd dat vooral behoefte is aan inzicht in herinplantproblemen bij pioenrozen en groeiproblemen bij Campanula en Delphinium. Onderzoek heeft aangetoond dat aaltjes niet de oorzaak zijn. Zowel kwekers als voorlichters vermoeden een rol voor toxische stoffen uit de planten zelf bij het ontstaan van deze problemen (allelopathie).

  4. Bioavailability of Allelochemicals in Soil

    Science.gov (United States)

    2008-02-27

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

  5. 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.

  6. Physiological conjunction of allelochemicals and desert plants.

    Science.gov (United States)

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

    2013-01-01

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

  7. 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.

  8. [Plant hydroponics and its application prospect in medicinal plants study].

    Science.gov (United States)

    Zeng, Yan; Guo, Lan-Ping; Huang, Lu-Qi; Sun, Yu-Zhang

    2007-03-01

    This article introduced the theorem and method of hydroponics. Some examples of studies in agriculture and forestry were presented, the effects of elements, environmental stress and hormones on physiology of medicinal plants by using hydroponics were analyzed. It also introduced the feasibility and advantage of hydroponics in intermediate propagation and allelopathy of medicinal plant. And finally it made the conclusion that the way of hydroponics would be widely used in medicinal plant study.

  9. Harmful and beneficial aspects of Parthenium hysterophorus: an update

    OpenAIRE

    Patel, Seema

    2011-01-01

    Parthenium hysterophorus is a noxious weed in America, Asia, Africa and Australia. This weed is considered to be a cause of allergic respiratory problems, contact dermatitis, mutagenicity in human and livestock. Crop production is drastically reduced owing to its allelopathy. Also aggressive dominance of this weed threatens biodiversity. Eradication of P. hysterophorus by burning, chemical herbicides, eucalyptus oil and biological control by leaf-feeding beetle, stem-galling moth, stem-boring...

  10. 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.

    to drug discovery for sustainable utilization of marine natural resources with special reference to the marine sponges. 2. Strategies to compete for space Marine invertebrates acquire living space by using various offensive and defensive strategies... common in marine hard substratum communities [32]. Amongst above four defensive strategies discussed, allelopathy or chemical defence is the most important in case of soft–bodied sessile invertebrates such as sponges, octocorals and ascidians which...

  11. Effects of Eichhornia crassipes Growth on Aquatic Plants in Dianchi Lake

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The aim was to study the effects of Eichhornia crassipes as an invasive plant on aquatic plants in Dianchi Lake. [Method] Based on the determination of chlorophyll content of phytoplankton and submerged plant (Potamogeton pectinatus) in Dianchi Lake in different months, the effects of E. crassipes on aquatic plants in Dianchi Lake were studied, and the allelopathy effect of root culture solution of E. crassipes on Microcystis aquaticum was discussed. [Result] The growth of E. crassipes in Dianch...

  12. 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

  13. Impact de la compétition et de l'allélopathie sur le trade-off entre défense et croissance pour deux espèces contrastées d'arbre.

    OpenAIRE

    Catherine eFERNANDEZ; Yogan eMONNIER; Mathieu eSANTONJA; Christiane eGALLET; Leslie A. WESTON; Bernard ePREVOSTO; Amelie eSAUNIER; Virginie eBALDY; Anne eBOUSQUET-MELOU

    2016-01-01

    In contrast to plant-animal interactions, the conceptual framework regarding the impact of secondary metabolites in mediating plant-plant interference is currently less well defined. Here, we address hypotheses about the role of chemically-mediated plant-plant interference (i.e., allelopathy) as a driver of Mediterranean forest dynamics. Growth and defense abilities of a pioneer (Pinus halepensis) and a late-successional (Quercus pubescens) Mediterranean forest species were evaluated under th...

  14. Wuchsdepressionen von Gehölzarten im Baumschulbereich

    OpenAIRE

    Spethmann, Wolfgang; Wilstermann, Maike

    2003-01-01

    Im Rahmen des Projektes wurden wissenschaftliche und populäre Veröffentlichungen zum Themenbereich Wachstumsdepressionen, Nachbauprobleme, Bodenmüdigkeit und Allelopathie recherchiert und ausgewertet. Es wurden Praktiker, Berater und Wissenschaftler befragt und die jeweiligen Ergebnisse in 3 Workshops diskutiert. Rosaceae sind von den Nachbauproblemen am stärksten betroffen. Die größte wirtschaftliche Bedeutung haben dabei Rose und Apfel. Mit großer Sicherheit kann ein Zusammenhang zwischen e...

  15. Allelopathy—A Tool to Improve the Weed Competitive Ability of Wheat with Herbicide-Resistant Black-Grass (Alopecurus myosuroides Huds.

    Directory of Open Access Journals (Sweden)

    Nils-Ove Bertholdsson

    2012-10-01

    Full Text Available Controlling black-grass in winter wheat production in northern Europe is an increasing problem because of more frequent winter crops and development of herbicide resistance in weeds. Alternative weed management strategies are needed, e.g., use of more competitive cultivars. Factors that increase cultivar competitiveness include early vigor and straw length, but also allelopathy. Therefore, the allelopathic properties of wheat cultivars included in the Swedish national list or in the release pipeline were investigated using a bioassay with herbicide-resistant and herbicide-sensitive black-grass as receiver plants. Wheat-rye translocation lines were also included in this screening to identify possible sources of high allelopathic activity. The bioassay results were followed up in two-year field trials. The results revealed large variations in allelopathic activity between cultivars. Most cultivars showed interference with both herbicide-sensitive and herbicide-resistant black-grass, although the allelopathic effect was lower on the herbicide-resistant biotype. Cultivars with high allelopathic activity gave only half the black-grass biomass of low allelopathic cultivars. Dinaro, a triticale (wheat-rye hybrid cultivar and the new wheat cultivar Nimbus showed the highest allelopathy and inhibition of black-grass growth. Only a few wheat lines with rye chromatin, all or part of a rye chromosome, showed high allelopathy. Use of cultivars with high allelopathic activity can thus be important in integrated weed management of black-grass.

  16. Allelopathic interactions between the brown algal genus Lobophora (Dictyotales, Phaeophyceae) and scleractinian corals

    Science.gov (United States)

    Vieira, Christophe; Thomas, Olivier P.; Culioli, Gérald; Genta-Jouve, Grégory; Houlbreque, Fanny; Gaubert, Julie; de Clerck, Olivier; Payri, Claude E.

    2016-01-01

    Allelopathy has been recently suggested as a mechanism by which macroalgae may outcompete corals in damaged reefs. Members of the brown algal genus Lobophora are commonly observed in close contact with scleractinian corals and have been considered responsible for negative effects of macroalgae to scleractinian corals. Recent field assays have suggested the potential role of chemical mediators in this interaction. We performed in situ bioassays testing the allelopathy of crude extracts and isolated compounds of several Lobophora species, naturally associated or not with corals, against four corals in New Caledonia. Our results showed that, regardless of their natural association with corals, organic extracts from species of the genus Lobophora are intrinsically capable of bleaching some coral species upon direct contact. Additionally, three new C21 polyunsaturated alcohols named lobophorenols A–C (1–3) were isolated and identified. Significant allelopathic effects against Acropora muricata were identified for these compounds. In situ observations in New Caledonia, however, indicated that while allelopathic interactions are likely to occur at the macroalgal-coral interface, Lobophora spp. rarely bleached their coral hosts. These findings are important toward our understanding of the importance of allelopathy versus other processes such as herbivory in the interaction between macroalgae and corals in reef ecosystems.

  17. 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.

  18. Allelopathic effect of a native species on a major plant invader in Europe

    Science.gov (United States)

    Christina, Mathias; Rouifed, Soraya; Puijalon, Sara; Vallier, Félix; Meiffren, Guillaume; Bellvert, Floriant; Piola, Florence

    2015-04-01

    Biological invasions have become a major global issue in ecosystem conservation. As formalized in the "novel weapon hypothesis", the allelopathic abilities of species are actively involved in invasion success. Here, we assume that allelopathy can also increase the biotic resistance of native species against invasion. We tested this hypothesis by studying the impact of the native species Sambucus ebulus on the colonization of propagules of the invasive species Fallopia x bohemica and the subsequent development of plants from these. Achenes and rhizome fragments from two natural populations were grown in a greenhouse experiment for 50 days. We used an experimental design that involved "donor" and "target" pots in order to separate resource competition from allelopathy. An allelopathic treatment effect was observed for plant growth but not for propagule establishment. Treatment affected, in particular, the growth of Fallopia plants originating from achenes, but there was less influence on plants originating from rhizomes. By day 50, shoot height had decreased by 27 % for plants originating from rhizomes and by 38 % for plants originating from achenes. The number of leaves for plants originating from achenes had only decreased by 20 %. Leaf and above- and below-ground dry masses decreased with treatment by 40, 41 and 25 % for plants originating from rhizomes and 70, 61 and 55 % for plants originating from achenes, respectively. S. ebulus extracts were analysed using high-performance chromatography, and the choice of test molecules was narrowed down. Our results suggest native species use allelopathy as a biotic containment mechanism against the naturalization of invasive species.

  19. Chemical ecology of marine plankton.

    Science.gov (United States)

    Schwartz, Emily R; Poulin, Remington X; Mojib, Nazia; Kubanek, Julia

    2016-07-28

    Covering: January 2013 to online publication December 2014This review summarizes recent research in the chemical ecology of marine pelagic ecosystems, and aims to provide a comprehensive overview of advances in the field in the time period covered. In order to highlight the role of chemical cues and toxins in plankton ecology this review has been organized by ecological interaction types starting with intraspecific interactions, then interspecific interactions (including facilitation and mutualism, host-parasite, allelopathy, and predator-prey), and finally community and ecosystem-wide interactions.

  20. Allelopathic effects of extracts from Solidago canadensis L.against seed germination and seedling growth of some plants

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To investigate the potential role of allelopathy in plant interference and in the successful invasion of alien species Solidago canadensis, aqueous and ethanolic extracts from rhizomes, stems and leaves of S. canadensis were prepared and used as treatment solutions to assess their effects on seed germination and seedling growth in four target species, mulberry (Morus alba); morning glory (Pharbitis nil), wheat (Triticum aestivum) and rape (Brassica campestris). Reduction and/or growth in germination and growth of the target plant species in the presence of both aqueous and ethanolic extracts at different concentrations indicated that the responses were species-specific and concentration-dependent. Generally, ethanolic extracts (especially from leaves) imposed stronger effects on both seed germination and seedling growth. Extracts with lower concentration at 0.001 g/ml dw could stimulate the seedling growth of rape and morning glory, whereas extracts at any given concentrations have inhibitory effects on wheat and mulberry. It is suggested that the aqueous and ethanolic extracts of all the three parts ofS. canadensis have significant allelopathic effects. Although both inhibition and stimulation occurred in the germination and growth of the target species, extracts with higher concentrations definitely inhibit seed germination and seedling growth of all target plants. We suggest that allelopathy plays a more important role than other mechanisms do in the out-competition of S. canadensis over other plants, and make it invasive in new habitats.

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

    Science.gov (United States)

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

    2013-02-01

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

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

    Science.gov (United States)

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

    2014-10-01

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

  3. Bryophyte spore germinability is inhibited by peatland substrates

    Science.gov (United States)

    Bu, Zhao-Jun; Li, Zhi; Liu, Li-Jie; Sundberg, Sebastian; Feng, Ya-Min; Yang, Yun-He; Liu, Shuang; Song, Xue; Zhang, Xing-Lin

    2017-01-01

    Bryophyte substrates and species may affect spore germination through allelopathy. Polytrichum strictum is currently expanding in peatlands in north-eastern China - is this an effect of its superior spore germinability or do its gametophytes have a stronger allelopathic effect than do Sphagnum? We conducted a spore burial experiment to test the effect of species identity, substrate and water table depth (WTD) on spore germinability and bryophyte allelopathic effect with P. strictum and two Sphagnum species (S. palustre and S. magellanicum). After 5 months of burial during a growing season, the spores were tested for germinability. Allelopathic effect of bryophyte substrates was assessed by the difference between spore germinability after being stored inside or outside the substrates. After burial, more than 90% of the spores lost their germinability across all three species due to ageing and allelopathy. Spore germinability differed among species, where the spores in S. palustre had a higher germination frequency than those in P. strictum. The three bryophytes maintained a higher germinability in Sphagnum than in Polytrichum hummocks, probably due to a stronger allelopathic effect of P. strictum. Water table drawdown by 10 cm increased germinability by more than 60% across the three species. The study indicates that P. strictum does not possess an advantage regarding spore germination but rather its gametophytes have a stronger allelopathic effect. Due to the weaker inhibitive effect of Sphagnum gametophytes, P. strictum may have a potential establishment superiority over Sphagnum in peatlands, in addition to a better drought tolerance, which may explain its current expansion.

  4. The influence of extracellular compounds produced by selected Baltic cyanobacteria, diatoms and dinoflagellates on growth of green algae Chlorella vulgaris

    Science.gov (United States)

    Żak, Adam; Kosakowska, Alicja

    2015-12-01

    Secondary metabolites produced by bacteria, fungi, algae and plants could affect the growth and development of biological and agricultural systems. This natural process that occurs worldwide is known as allelopathy. The main goal of this work was to investigate the influence of metabolites obtained from phytoplankton monocultures on the growth of green algae Chlorella vulgaris. We selected 6 species occurring in the Baltic Sea from 3 different taxonomic groups: cyanobacteria (Aphanizomenon flos-aquae; Planktothrix agardhii), diatoms (Thalassiosira pseudonana; Chaetoceros wighamii) and dinoflagellates (Alexandrium ostenfeldii; Prorocentrum minimum). In this study we have demonstrated that some of selected organisms caused allelopathic effects against microalgae. Both the negative and positive effects of collected cell-free filtrates on C. vulgaris growth, chlorophyll a concentration and fluorescence parameters (OJIP, QY, NPQ) have been observed. No evidence has been found for the impact on morphology and viability of C. vulgaris cells.

  5. Strategies for transgenic manipulation of monoterpene biosynthesis in plants.

    Science.gov (United States)

    Mahmoud, Soheil S; Croteau, Rodney B

    2002-08-01

    Monoterpenes, the C(10) isoprenoids, are a large family of natural products that are best known as constituents of the essential oils and defensive oleoresins of aromatic plants. In addition to ecological roles in pollinator attraction, allelopathy and plant defense, monoterpenes are used extensively in the food, cosmetic and pharmaceutical industries. The importance of these plant products has prompted the definition of many monoterpene biosynthetic pathways, the cloning of the relevant genes and the development of genetic transformation techniques for agronomically significant monoterpene-producing plants. Metabolic engineering of monoterpene biosynthesis in the model plant peppermint has resulted in yield increase and compositional improvement of the essential oil, and also provided strategies for manipulating flavor and fragrance production, and plant defense.

  6. 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

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

    Science.gov (United States)

    Saxena, S; Pandey, A K

    2001-05-01

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

  8. 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.

  9. Potential of Root Exudates from Wetland Plants and Their Potential Role for Denitrification and Allelopathic Interactions

    DEFF Research Database (Denmark)

    Zhai, Xu

    chemicals to suppress the growth of native species. Phragmites australis is recognized as the most invasive species in wetland ecosystems in North America, and allelopathy has been reported to be involved in the invasion success of the introduced exotic P. australis. The composition of the root exudates may...... vary among different Phragmites haplotypes and consequently affect their invasion potential. The studies presented in this dissertation aimed at investigating the quantity and composition of the organic carbon released in root exudates from three common wetland species as affected by temperature...... plants contribute to nitrogen removal in high nitrate and low BOD wastewater. Also, the compositions and quantity of root exudates differed among the species of the Phragmites genus and the Phragmites haplotypes. The research could not confirm that gallic acid in root exudates is responsible...

  10. 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

  11. 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.

  12. Level of catechin, myricetin, quercetin and isoquercitrin in buckwheat (Fagopyrum esculentum Moench), changes of their levels during vegetation and their effect on the growth of selected weeds.

    Science.gov (United States)

    Kalinova, Jana; Vrchotova, Nadezda

    2009-04-01

    Buckwheat is well-known as a crop rich in flavonoids, however, attention has usually only been paid to the main flavonoid rutin as an important natural antioxidant or as a possible allelopathic compound. Therefore, some of the other constituents found within individual plant parts of buckwheat (isoquercitrin, quercetin, catechin, and myricetin), as well as changes of their level during the growing season, were determined by HPLC analysis. The effects of these compounds on plant growth were proved on seven plant species. In buckwheat, isoquercitrin represented the largest component of the selected compounds. The strongest inhibitive effects on the growth of those selected plants were produced by catechin. Quercetin and isoquercitrin had weak inhibitive effects. Myricetin did not show any influence on plant growth. Hence we suppose that myricetin, isoquercetin and quercetin do not have important function in allelopathy of buckwheat. Buckwheat as row material for functional foods could be a significant source of another antioxidant, isoquercitrin.

  13. Taking ecological function seriously: soil microbial communities can obviate allelopathic effects of released metabolites.

    Directory of Open Access Journals (Sweden)

    Harleen Kaur

    Full Text Available BACKGROUND: Allelopathy (negative, plant-plant chemical interactions has been largely studied as an autecological process, often assuming simplistic associations between pairs of isolated species. The growth inhibition of a species in filter paper bioassay enriched with a single chemical is commonly interpreted as evidence of an allelopathic interaction, but for some of these putative examples of allelopathy, the results have not been verifiable in more natural settings with plants growing in soil. METHODOLOGY/PRINCIPAL FINDINGS: On the basis of filter paper bioassay, a recent study established allelopathic effects of m-tyrosine, a component of root exudates of Festuca rubra ssp. commutata. We re-examined the allelopathic effects of m-tyrosine to understand its dynamics in soil environment. Allelopathic potential of m-tyrosine with filter paper and soil (non-sterile or sterile bioassays was studied using Lactuca sativa, Phalaris minor and Bambusa arundinacea as assay species. Experimental application of m-tyrosine to non-sterile and sterile soil revealed the impact of soil microbial communities in determining the soil concentration of m-tyrosine and growth responses. CONCLUSIONS/SIGNIFICANCE: Here, we show that the allelopathic effects of m-tyrosine, which could be seen in sterilized soil with particular plant species were significantly diminished when non-sterile soil was used, which points to an important role for rhizosphere-specific and bulk soil microbial activity in determining the outcome of this allelopathic interaction. Our data show that the amounts of m-tyrosine required for root growth inhibition were higher than what would normally be found in F. rubra ssp. commutata rhizosphere. We hope that our study will motivate researchers to integrate the role of soil microbial communities in bioassays in allelopathic research so that its importance in plant-plant competitive interactions can be thoroughly evaluated.

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

    Science.gov (United States)

    Yang, X-F; Kong, C-H

    2017-02-20

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

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

    Science.gov (United States)

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

    2010-07-01

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

  16. Allelopathic activity of some grass species on Phleum pratense seed germination subject to their density

    Directory of Open Access Journals (Sweden)

    Halina Lipińska

    2012-12-01

    Full Text Available Efficient utilization of allelopathy in the agricultural practice requires searching for some species and developmental stages when the allelopathic substances are generated in bioactive concentrations. That also requires the knowledge of allelopathy mechanisms and primarily its separation from the other aspects of plant activity, mainly from competition for environmental resources. This task, however, has remained vital in the studies on plant interference, being extremely difficult to perform under field conditions. Therefore, the studies were conducted in the laboratory. To determine the activity of an allelopathic agent of the selected grass species, the density dependent phytotoxicity model was employed. The model is based on the fact that an increase of acceptor plants density evokes a decrease of their response to the allelopathic compounds, whereas the negative effects of the competition become more intense. A higher rate of acceptor plants growth accompanying their density increase in the given object does not agree with the competition rules and thus, it may imply an allelopathic background of the observed changes. In the presented studies, the allelopathic properties of grasses - donors were evaluated by studying the effect of two densities of the emerging seeds and two- and four weeks aged seedlings of F. arundinacea, L. multiflorum, L. perenne and P. pratensis. The tested species - acceptor Ph. pratensis was sown in the density of 10 and 20 seeds in a pan. The results revealed that the germination of acceptor seeds was differentiated depending on their density in the pan, and on the species, density and the age of the donor. Inhibition of Ph. pratense seed germination in objects with a lover density may prove allelopathic effects of the studied donor grasses.

  17. 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

  18. Causes of alpine grassland degradation and its restoration strategy in Tianzhu County%天祝高寒草地退化原因分析与治理策略

    Institute of Scientific and Technical Information of China (English)

    徐长林; 鱼小军

    2011-01-01

    Tianzhu County with vast alpine grassland is one of Gansu province's important pastoral areas. This study reviewed the causes of grassland degradation at broad and home, and then proposed that the fragile ecological environment was the intrinsic factors, which caused alpine grassland to degrade in the Tianzhu County. The human activities such as disturbance and unreasonable utilization were the major driver for grassland degradation, and global warming accelerated the grassland degradation. This study also proposed that the loss of livestock manure, allelopathy among plants and self-allelopathy were important causes of grassland degradation. Finally, this study put forward some measures to restore the degraded alpine grassland, which included rational carrying capacity and the increase of marketing rate for livestock, and include fencing and establishment of artificial grassland for improvement grassland. Meanwhile, the rodents and pests integrated control, intellectual restoration , and extension of science and technology would be benefit the restoration of alpine grassland reviewed.%天祝高寒草地是甘肃省重要的牧区之一。借鉴国内外相关研究进展,综合认为脆弱的生态环境是天祝高寒草地退化的内因,人类不合理的利用和干扰是高寒草地退化的主要驱动力,气候变暖、变干加速了高寒草地的退化。并认为家畜粪便的流失、植物的化感作用和自毒作用也是导致天祝高寒草地退化的原因。提出了天祝高寒草地的整体治理策略,即以草定畜、提高出栏率,轻度和中度退化草地进行草地改良、围栏,重度退化草地进行栽培草地建植,同时结合草地鼠害综合治理、加强人才建设与加快科技成果推广和转化。

  19. 芦笋不同组织水浸提液对辣椒的化感效应%Allelopathic Effect of Water Extracts from Different Parts of Asparagus officinalis L.on Hot Pepper

    Institute of Scientific and Technical Information of China (English)

    严泽生; 徐冬梅; 贺忠群

    2011-01-01

    [目的]测定芦笋不同组织浸提液对辣椒的化感效应.[方法]以辣椒为侵体,通过测定芦笋不同部分水浸提液对辣椒种子萌芽和幼苗生长的影响,研究芦笋对辣椒的化感效应.[结果]芦笋地上部和地下部组织水浸提液对辣椒种子发芽率、发芽指数均表现出抑制作用;高浓度芦笋地上部和地下部组织水浸提液对辣椒幼苗的生长及叶绿素含量均具有抑制作用,而低浓度浸提液具有促进作用.芦笋不同组织部位水浸提液的化感作用强弱不同,地上部分水浸提液化感作用明显强于地下部分.[结论]该研究为选择芦笋的间作作物及其秸杆的再利用提供了依据.%[ Objective ] To discuss the allelopathic effect of water extracts from different parts of Allelopathy of Asparagus officinalis L. On hot pepper. [Method] Using hot pepper as the receptor, effect of water extracts from different parts of Asparagus officinalis L. On seed germination and seedling growth were determined, investigating the allelopathy of Asparagus officinalis L. To hot pepper. [ Result ] Water extracts of aboveground and underground parts of Asparagus officinalis L. Showed inhibitory effect on germination rate and germination index of hot pepper. High concentration water extracts all showed inhibitory effect on seedling growth and content of chlorophyll,while low concentration ones presented facilitating effect on them. In addition, ailelopathic effect of water extracts from above ground of Asparagus officinalis L. Was stronger than that from under ground. [ Conclusion] This work is of considerable value for selection of interculture of Asparagus officinalis L. And reuse of straw of it.

  20. 赤潮异弯藻对孔石莼生长及其某些生理特性的影响%Effects of Heterosigma akashiwo (Hada) Hada on the growth and physiological characteristics of Ulva pertusa Kjellm

    Institute of Scientific and Technical Information of China (English)

    蔡恒江; 李博; 刘长发

    2012-01-01

    通过实验生态学和生物化学的方法,研究了赤潮异弯藻[ Heterosigma akashiwo (Hada) Hada]对孔石莼(Ulva pertusa Kjellman)生长及其叶绿素a(Chl-a)含量、丙二醛(MDA)含量、总抗氧化能力(T-AOC)、过氧化氢酶(CAT)活力、超氧化物歧化酶(SOD)活力和谷胱甘肽过氧化酶(GPX)活力的影响.结果表明:孔石莼的克生作用会明显抑制赤潮异弯藻的生长,同时赤潮异弯藻也会抑制孔石莼的生长,且孔石莼生理生化特性对其有明显的响应.赤潮异弯藻会使孔石莼CAT活力和MDA含量呈现升高的趋势;GPX活力呈现下降的趋势;T-AOC和T-SOD活力呈现先下降后升高趋势;Chl-a含量并无明显变化.推测赤潮异弯藻克生作用诱导孔石莼产生活性氧自由基,是藻体受损伤的主要原因.%The effects of Heterosigma akashiwo ( Hada) Hada on the growth,physiological characteristics including Chl-a content,MDA content,T-AOC,CAT activity,SOD activity and GPX activity of Ulva pertusa Kjellman were studied by experimental ecology and biochemical methods.The results demonstrated that U.pertusa could inhibit the growth of H.akashiwo,and H.akashiwo could inhibit the growth of U.pertusa simultaneously.The effects of U.perlusa on physiological characteristics were obvious.The MDA content and,CAT activity showed increasing trend,but GPX activity showed decreasing trend while T-AOC and T-SOD showed decreasing trend from 3d to 6d and increasing trend from 9d to 12d under allelopathy from H.akashiwo.The change of Chl-a content was not obvious.Superfluous reactive oxygen species produced by allelopathy from H.akashiwo was main reasons for the damage of U.pertusa.

  1. Emerging Insights on Brazilian Pepper Tree (Schinus terebinthifolius) Invasion: The Potential Role of Soil Microorganisms

    Science.gov (United States)

    Dawkins, Karim; Esiobu, Nwadiuto

    2016-01-01

    Invasive plant species constitute a major ecological and economic problem worldwide, often distorting trophic levels and ecosystem balance. Numerous studies implicate factors ranging from environmental plasticity, competition for nutrient and space, and allelopathy in the success of invasive species in general. The Brazilian Pepper tree (BP) was introduced to the United States in the 1800s and has since become a category one invasive plant in Florida. It has aggressively spread to about 3000 km2 of terrestrial surface, fueled in part by the prevalence of the hybrid genotypes and environmental perturbations. It displays some of the well-established invasive mechanisms but there is a serious dearth of knowledge on the plant–microbe–soil interactions and whether the rhizobiome plays any roles in the displacement of native flora and the range expansion of BP. Several control measures, including chemical, mechanical, and biological antagonism have been used with limited success while restoration of natives in soils from which BP was removed has proved problematic partly due to a poorly understood phenomenon described as the “BP legacy effect.” Emerging evidence suggests that allelopathy, selective recruitment of beneficial soil microbes, disruption of microbial community structure and alteration of nutrient cycling, exhibited by many other invasive plant species may also be involved in the case of BP. This brief review discusses the well-established BP invasion mechanisms and highlights the current understanding of the molecular, below-ground processes. It also points out the gaps in studies on the potential role of microbial interactions in the success of BP invasion. These hitherto poorly studied mechanisms could further explain the aggressive spread of BP and could potentially contribute significantly to effective control measures and enable appropriate strategies for restoring native plants. The review advocates for the use of cutting-edge techniques in

  2. Efeito alelopático e toxicidade frente à Artemia salina Leach dos extatos do fruto de Euterpe edulis Martius Allelopathic effects and toxicity against Artemia salina Leach of extracts of the fruit of Euterpe edulis Martius

    Directory of Open Access Journals (Sweden)

    Cristina Peitz de Lima

    2011-06-01

    Full Text Available Alelopatia é um processo envolvendo metabólitos secundários produzidos por plantas que infl uenciam o crescimento e desenvolvimento de sistemas agrícolas. Devido à toxicidade dos herbicidas sintéticos para o meio ambiente e para a saúde humana tem-se aumentado o interesse na exploração da alelopatia como uma alternativa para o controle de plantas daninhas. O presente trabalho avaliou efeito dos extratos dos frutos de Euterpe edulis Martius sobre o desenvolvimento de cipselas e plântulas de Lactuca sativa Linné, foram determinados o índice de velocidade de germinação, o crescimento da radícula e do hipocótilo. Para a avaliação da toxicidade dos extratos foi realizado o ensaio de toxicidade frente ao microcrustáceo Artemia salina Leach determinando-se a CL50 e percentual de mortalidade. A fração remanescente demonstrou efeito alelopático, pois todas as concentrações alteraram os valores do índice de velocidade de germinação e as concentrações de 0,2 e 0,4 mg inibiram tanto o crescimento da radícula quanto o crescimento do hipocótilo. No ensaio de toxicidade todos os extratos apresentaram CL50 superior a 1000 ppm e 0% de mortalidade das artemias, indicando a não toxicidade dos extratos.Allelopathy is a process involving secondary metabolites produced by plants that influence growth and development of agricultural systems. Because of the toxicity of synthetic herbicides to the environment and human health, there has been increased interest in exploiting allelopathy as an alternative for weed control. This study evaluated the eff ect of extracts of Euterpe edulis Martius fruits on the development of cypselae and seedlings of Lactuca sativa Linné; the germination speed index, radicle and hypocotyl growth were determined. To evaluate the toxicity of the extracts the toxicity test against Artemia salina Leach was used, where the LC50 and mortality rate were determined. Th e remaining fraction showed allelopathic effect

  3. Allelopathic Sensitivity of Five Economic Species to Aqueous Leaf Extract of Eucalyptus urophylla × E.grandis with Different Ages%5种经济植物对幼龄尾巨桉叶片提取液的化感敏感性

    Institute of Scientific and Technical Information of China (English)

    王小雪; 刘芸; 邵呈龙; 唐小荐; 黄小辉; 吴艳冰; 唐吉芳; 何炳辉

    2011-01-01

    近几年,随着重庆"森林工程"全面启动,重庆西部主要区县充分利用当地有利自然条件,大规模发展速生桉树人工用材林.种植桉树需5年以上才能产生经济效益,因此,开展幼龄林林下种植成为以短养长、提高桉农收益的有效途径.但很多研究发现:桉树不仅具有较强的水、肥竞争力,而且作为一种外来树种,化感作用为其在新生境的生长和繁殖提供了"Novel weapon"(Bais et al.,2003;Hierro et al.,2003;吴锦容等,2005).%In order to guide scientifically planting on forest floor in eucalyptus plantations, screen suitable plants, and understand allelopathic effects of eucalyptus trees with different young ages (1 a, 2 a and 3 a) on the understory species and growth germination rate and seedling growth of five species widely planted in the local region were measured after treatments with different concentration of aqueous leaf extract of Eucalyptus urophylla × E. Grandis treatments with different concentration. The results showed that the leaf extract reduced seed germination rate and inhibited seedling growth of all five species, and had a stronger inhibiting effect on radical than hypocotyl growth. The species tested in this study had different sensitivity to the leaf extract. The inhibition rate of Lolium perenne, Sorghum sudanense, Phaseolus aureus, Phaseolus vulgaris and Glycine max was 56. 85% , 54. 58% , 33. 48% , 20. 81% , 16. 01% , respectively, among which Giycine max and Phaseolus vulgaris were the most insensitive to the leaf extract. The allelopathy of the leaf extract was concentration dependent, increasing with increase of the concentration, and low concentration (0.01 g · mL-1 ) had no significant influence on the species. Furthermore, the allelopathy aqueous leaf extract of E. Urophylla × E. Grandis to the five species had no significant difference with increase of their ages.

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

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    Ribas Antonio Vidal

    1997-06-01

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

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

    Science.gov (United States)

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

    2008-06-01

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

  6. Lily Cultivars Have Allelopathic Potential in Controlling Orobanche aegyptiaca Persoon.

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    Min Chai

    Full Text Available As a devastating holoparasitic weed, Orobanche aegyptiaca Persoon. (Egyptian broomrape causes serious damage to agricultural production and threatens economic development, which has raised widespread concern. The present study was conducted to determine whether lilies have the potential to be used as 'trap crops' for controlling O. aegyptiaca Persoon. In the experiments, the ability of three popular lily cultivars (Lilium Oriental hybrids 'Sorbonne', Lilium LA (Longiflorum hybrids x Asiatic hybrids hybrids 'Ceb Dazzle', and Lilium Longiflorum hybrids (L. formosanum x L. longiflorum 'L. formolongo' to induce O. aegyptiaca Persoon. seed germination was assessed. Parts of the three lily cultivars, including the rhizosphere soil and underground and above-ground organs, all induced "suicidal germination" of parasitic O. aegyptiaca Persoon. seed at four growth stages. Specifically, Sorbonne and Ceb Dazzle behaved with similar allelopathy, and the bulb, scale leaf and aerial stem exhibited stronger allelopathic effects on O. aegyptiaca Pers. germination compared to other organs. Aqueous L. formolongo leaf extracts may contain more stable, effective stimulants given that they induced the highest germination rate at 76.7% even though the extracts were serially diluted. We speculate that these organs may be advantageous in further isolating and purifying economical active substances that can be substitutes for GR24. These results indicate that lilies have the potential to be used as a trap crops or can be processed into green herbicide formulations that can be applied in agriculture production to rapidly deplete the seed bank of O. aegyptiaca Persoon. parasitic weeds in soil.

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

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    Amir MOOSAVI

    2011-05-01

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

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

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    Dong Xu

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

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

    Science.gov (United States)

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

    2012-01-01

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

  10. Allelopathic Effects of Invasive Woody Plant Species in Hungary

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    CSISZÁR, Ágnes

    2009-01-01

    Full Text Available Allelopathy may play an important role in the invasion success of adventive plant species.The aim of this study was to determine the allelopathic potential of invasive woody plant species occurringin Hungary. Juglone index of fourteen invasive woody plant species in Hungary was determined by themethod of Szabó (1997, comparing the effects of juglone and substance extracted of plant species withunknown allelopathic potential on the germination rate, shoot length and rooth length of white mustard(Sinapis alba L. used as receiver species. Results have proven a more or less expressed allelopathicpotential in case of all species. The juglone index at higher concentration extracts (5 g dry plant materialextracted with 100 ml distilled water of almost every studied species approaches to 1 or is above 1, thismeans the effect of the extracts is similar to juglone or surpasses it. In terms of juglone index, theallelopathic potential of false indigo (Amorpha fruticosa L., tree-of-heaven (Ailanthus altissima (Mill.Swingle and hackberry (Celtis occidentalis L. were the highest. Besides these species the treatment withthe extracts of black walnut (Juglans nigra L., black cherry (Prunus serotina Ehrh. and green ash(Fraxinus pennsylvanica MARSH. var. subintegerrima (Vahl Fern. reduced extremely significantly thegermination rate, shoot and root length, compared to the control.

  11. Rutin-Mediated Priming of Plant Resistance to Three Bacterial Pathogens Initiating the Early SA Signal Pathway.

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    Wei Yang

    Full Text Available Flavonoids are ubiquitous in the plant kingdom and have many diverse functions, including UV protection, auxin transport inhibition, allelopathy, flower coloring and insect resistance. Here we show that rutin, a proud member of the flavonoid family, could be functional as an activator to improve plant disease resistances. Three plant species pretreated with 2 mM rutin were found to enhance resistance to Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Pseudomonas syringae pv. tomato strain DC3000 in rice, tobacco and Arabidopsis thaliana respectively. While they were normally propagated on the cultural medium supplemented with 2 mM rutin for those pathogenic bacteria. The enhanced resistance was associated with primed expression of several pathogenesis-related genes. We also demonstrated that the rutin-mediated priming resistance was attenuated in npr1, eds1, eds5, pad4-1, ndr1 mutants, and NahG transgenic Arabidopsis plant, while not in either snc1-11, ein2-5 or jar1 mutants. We concluded that the rutin-priming defense signal was modulated by the salicylic acid (SA-dependent pathway from an early stage upstream of NDR1 and EDS1.

  12. Rutin-Mediated Priming of Plant Resistance to Three Bacterial Pathogens Initiating the Early SA Signal Pathway.

    Science.gov (United States)

    Yang, Wei; Xu, Xiaonan; Li, Yang; Wang, Yingzi; Li, Ming; Wang, Yong; Ding, Xinhua; Chu, Zhaohui

    2016-01-01

    Flavonoids are ubiquitous in the plant kingdom and have many diverse functions, including UV protection, auxin transport inhibition, allelopathy, flower coloring and insect resistance. Here we show that rutin, a proud member of the flavonoid family, could be functional as an activator to improve plant disease resistances. Three plant species pretreated with 2 mM rutin were found to enhance resistance to Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Pseudomonas syringae pv. tomato strain DC3000 in rice, tobacco and Arabidopsis thaliana respectively. While they were normally propagated on the cultural medium supplemented with 2 mM rutin for those pathogenic bacteria. The enhanced resistance was associated with primed expression of several pathogenesis-related genes. We also demonstrated that the rutin-mediated priming resistance was attenuated in npr1, eds1, eds5, pad4-1, ndr1 mutants, and NahG transgenic Arabidopsis plant, while not in either snc1-11, ein2-5 or jar1 mutants. We concluded that the rutin-priming defense signal was modulated by the salicylic acid (SA)-dependent pathway from an early stage upstream of NDR1 and EDS1.

  13. Cruciferous plants: phytochemical toxicity versus cancer chemoprotection.

    Science.gov (United States)

    Assayed, Mohamed E; Abd El-Aty, A M

    2009-11-01

    The Cruciferae (also known as the Brassicaceae) are the family of plants that include the various familiar members of the species Brassica oleracea (e.g., broccoli, cabbage, cauliflower, kale, Brussels sprouts) as well as many other plants that are widely consumed in various parts of the world. Forage and root brassicas are widely used as winter feeds for cattle and sheep. A striking and characteristic chemical property of cruciferous plants is their high content of glucosinolates (more than 120 types), which often approaches 1% or more of their dry weight. The interest devoted to this group of natural products is caused by the appreciable biological effects of both the intact glucosinolates (GSLs) and especially the complex group of glucosinolate transformation products produced in non-enzymatic and enzymatic reactions. Depending on the concentration and structural types of these compounds, their biological effects can be toxic, anti-nutritional or beneficial to health. Most serious economic problems in livestock seem to result from rapeseed meal; arising from GSLs or their breakdown products. In contrast, GSLs and their isothiocyanate (ITC) hydrolysis products are reportedly well-known protectors against carcinogenesis. GSLs play further protective and evolutionarily important roles in plants. These include allelopathy (suppression of growth of neighboring plants), specific positive and negative feeding cues for some insects and broad antibiotic properties including nematocidal, antimicrobial, antifungal, antiprotozoal and insecticidal activities. The controversy in the referred actions contributed to crucifers' phytochemicals has been exclusively discussed.

  14. A phytotoxic active substance in the decomposing litter of the fern Gleichenia japonica.

    Science.gov (United States)

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

    2015-03-15

    The fern Gleichenia japonica often dominates plant communities by forming large monospecific stands throughout the temperate to tropical Asia. The objective of this study was the investigation of allelopathic property and substances of the decomposing litter of the fern to evaluate the possible involvement of its allelopathy in the domination. An aqueous methanol extract of G. japonica litter inhibited the growth of garden cress (Lepidium sativum), lettuce (Lactuca sativa), barnyard grass (Echinochloa crus-galli), and ryegrass (Lolium multiflorum). This result suggests that G. japonica litter contains growth inhibitory substances. The extract was purified by chromatography while monitoring the inhibitory activity, and a growth inhibitory substance was isolated. The chemical structure of the substance was determined by spectral data to be a novel compound, 13-O-β-fucopyranosyl-3β-hydroxymanool. This compound inhibited root and shoot growth of garden cress and barnyard grass at concentrations ranging from 89.7 to 271 μM for 50% inhibition. In addition, the compound had potent growth inhibitory activity with the soil taken from near the colony. The concentration of the compound in soil under a pure colony of G. japonica was 790 μM, suggesting that the compound may contribute to the establishment of monocultural stands by this fern.

  15. Phenolic Phytoalexins in Rice: Biological Functions and Biosynthesis

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    Man-Ho Cho

    2015-12-01

    Full Text Available Phytoalexins are inducible secondary metabolites possessing antimicrobial activity against phytopathogens. Rice produces a wide array of phytoalexins in response to pathogen attacks and environmental stresses. With few exceptions, most phytoalexins identified in rice are diterpenoid compounds. Until very recently, flavonoid sakuranetin was the only known phenolic phytoalexin in rice. However, recent studies have shown that phenylamides are involved in defense against pathogen attacks in rice. Phenylamides are amine-conjugated phenolic acids that are induced by pathogen infections and abiotic stresses including ultra violet (UV radiation in rice. Stress-induced phenylamides, such as N-trans-cinnamoyltryptamine, N-p-coumaroylserotonin and N-cinnamoyltyramine, have been reported to possess antimicrobial activities against rice bacterial and fungal pathogens, an indication of their direct inhibitory roles against invading pathogens. This finding suggests that phenylamides act as phytoalexins in rice and belong to phenolic phytoalexins along with sakuranetin. Phenylamides also have been implicated in cell wall reinforcement for disease resistance and allelopathy of rice. Synthesis of phenolic phytoalexins is stimulated by phytopathogen attacks and abiotic challenges including UV radiation. Accumulating evidence has demonstrated that biosynthetic pathways including the shikimate, phenylpropanoid and arylmonoamine pathways are coordinately activated for phenolic phytoalexin synthesis, and related genes are induced by biotic and abiotic stresses in rice.

  16. Pequi leaves incorporated into the soil reduce the initial growth of cultivated, invasive and native species

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    LAÍSA N. ALLEM

    2014-12-01

    Full Text Available Studies have identified the phytotoxicity of many native species of the Cerrado; however, most of them were conducted either in inert substrates, or using exaggerate proportions of plant material. We investigated the phytotoxicity of pequi leaves added to substrate soil in quantities compatible with the litter produced by this species. Pequi leaves were triturated and added to red latosol in concentrations of 0.75%, 1.5% and 3%; the control was constituted of leafless soil. These mixtures were added to pots and irrigated daily to keep them moist. Germinated seeds of the cultivated sorghum and sesame, of the invasive brachiaria and of the native purple ipê, were disposed in the pots to grow for five to seven days at 30°C within a photoperiod of 12 h. Seedlings of all the species presented a reduction in their initial growth in a dose-dependent way. In general, the root growth was more affected by the treatments than the shoot growth; moreover, signs of necrosis were observed in the roots of the sorghum, sesame and brachiaria. The phytotoxic effects generated by relatively small quantities of leaves, in a reasonable range of species within a soil substrate, suggest potential allelopathy of pequi leaves under natural conditions.

  17. Molecular and structural changes induced by essential oils treatments in Vicia faba roots detected by genotoxicity testing.

    Science.gov (United States)

    Sturchio, Elena; Boccia, Priscilla; Zanellato, Miriam; Meconi, Claudia; Donnarumma, Lucia; Mercurio, Giuseppe; Mecozzi, Mauro

    2016-01-01

    Over the last few years, there has been an increased interest in exploiting allelopathy in organic agriculture. The aim of this investigation was to examine the effects of essential oil mixtures in order to establish their allelopathic use in agriculture. Two mixtures of essential oils consisting respectively of tea tree oil (TTO) and clove plus rosemary (C + R) oils were tested. Phytotoxicity and genotoxicity tests on the root meristems of Vicia faba minor were performed. A phytotoxic influence was particularly relevant for C + R mixture, while genotoxicity tests revealed significant results with both C + R oil mixture and TTO. Phenotypic analysis on Vicia faba minor primary roots following C + R oil mixture treatment resulted in callose production, an early symptom attributed to lipid peroxidation. The approach described in this study, based on genotoxicity bioassays, might identify specific DNA damage induced by essential oil treatments. These tests may represent a powerful method to evaluate potential adverse effects of different mixtures of essential oils that might be useful in alternative agriculture. Future studies are focusing on the positive synergism of more complex mixtures of essential oils in order to reduce concentrations of potentially toxic components while at the same time maintaining efficacy in antimicrobial and antifungal management.

  18. Sesquiterpenoids Lactones: Benefits to Plants and People

    Directory of Open Access Journals (Sweden)

    Carol Wagstaff

    2013-06-01

    Full Text Available Sesquiterpenoids, and specifically sesquiterpene lactones from Asteraceae, may play a highly significant role in human health, both as part of a balanced diet and as pharmaceutical agents, due to their potential for the treatment of cardiovascular disease and cancer. This review highlights the role of sesquiterpene lactones endogenously in the plants that produce them, and explores mechanisms by which they interact in animal and human consumers of these plants. Several mechanisms are proposed for the reduction of inflammation and tumorigenesis at potentially achievable levels in humans. Plants can be classified by their specific array of produced sesquiterpene lactones, showing high levels of translational control. Studies of folk medicines implicate sesquiterpene lactones as the active ingredient in many treatments for other ailments such as diarrhea, burns, influenza, and neurodegradation. In addition to the anti-inflammatory response, sesquiterpene lactones have been found to sensitize tumor cells to conventional drug treatments. This review explores the varied ecological roles of sesquiterpenes in the plant producer, depending upon the plant and the compound. These include allelopathy with other plants, insects, and microbes, thereby causing behavioural or developmental modification to these secondary organisms to the benefit of the sesquiterpenoid producer. Some sesquiterpenoid lactones are antimicrobial, disrupting the cell wall of fungi and invasive bacteria, whereas others protect the plant from environmental stresses that would otherwise cause oxidative damage. Many of the compounds are effective due to their bitter flavor, which has obvious implications for human consumers. The implications of sesquiterpenoid lactone qualities for future crop production are discussed.

  19. Bioscreening of Oxypeucedanin, a Known Furanocoumarin

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    Seyed Mehdi Razavi

    Full Text Available Objective(sAs an important class of natural products, coumarins exhibit many biological activities and the diversity of their bioactivity is so huge that the pharmacological promiscuity has been applied on their case. Oxypeucedanine also named as prangolarin is a linear furanocoumarin with an oxygenated prenylated substitution at C-5 of the nucleus. To our knowledge, there are few reports on pharmacological and biological activities of this compound. In the present work, we focused on some bioactive aspects of it.Materials and MethodsIn the present work, the compound was purified from Prangos uloptera using TLC and its phytotoxic, antibacterial, antifungal, antioxidant and cytotoxic effects were evaluated by Lettuce assay, disc diffusion method, mycelia radial growth, DPPH and MTT assays, respectively.Results Our results revealed that oxypeucedanin exhibit considerable phytotoxic activity and might play an allelopathic role for plants. The compound indicated high cytotoxic activity with IC50 value of 314 µg/ml. No antipathogenic and antioxidant activity were found for oxypeucedanin in this study. ConclusionWe conclude that oxypeucedanin (found in some vegetables can be considered as an antiproliferative agent. Keywords: Allelopathy, Antiproliferative agent, Cytotoxic activity, Oxypeucedanin, Phytotoxic activity, Prangos uloptera

  20. Allelopathic control of cyanobacterial blooms by periphyton biofilms.

    Science.gov (United States)

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

    2011-03-01

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

  1. Phytotoxic effects of Calotropis procera (Ait. R. Br. extract on three weed plants

    Directory of Open Access Journals (Sweden)

    Gulzar, A.

    2014-11-01

    Full Text Available A study was conducted to determine the potential and nature of allelopathic interference of Calotropis procera on seed germination and seedling growth of three weed species (Ageratum conyzoides L., Cannabis sativa L. and Trifolium repens L. Aqueous extracts of Calotropis procera at 0.5, 1.0, 2.0 and 4.0% concentrations were applied to determine their effect on seed germination and seedling growth of test plants under laboratory conditions. The aqueous extracts had retardary effect on seed germination, root length and shoot length. Germination percentage, root length and shoot length of weed species decreased progressively when treated with increasing extract concentration (0.5, 1, 2 and 4%. The pH values did not increase at all extract concentrations. Therefore, the change in pH values in this experiment is not responsible for the inhibition of test species growth.The phenolic content analysed show more pronounced increase in its contents at 4% concentrations. The study concludes that C. procera releases phenolics into the extract and these are probably involved in the growth inhibitory effect, which causes allelopathy operative in the community dominated by C. procera and provide an advantage to the weed.

  2. Vermicomposting eliminates the toxicity of Lantana (Lantana camara) and turns it into a plant friendly organic fertilizer.

    Science.gov (United States)

    Hussain, N; Abbasi, Tasneem; Abbasi, S A

    2015-11-15

    In evidently the first study of its kind, vermicompost derived solely from a weed known to possess plant and animal toxicity was used to assess its impact on the germination and early growth of several plant species. No pre-composting or supplementation of animal manure was done to generate the vermicompost in order to ensure that the impact is clearly attributable to the weed. Whereas the weed used in this study, Lantana (Lantana camara), is known to possess strong negative allelopathy, besides plant/animal toxicity in other forms, its vermicompost was seen to be a good organic fertilizer as it increased germination success and encouraged growth of all the three botanical species explored by the authors - green gram (Vigna radiata), ladies finger (Abelmoschus esculentus) and cucumber (Cucumis sativus). In terms of several physical, chemical and biochemical attributes that were studied, the vermicompost appeared plant-friendly, giving best results in general when employed at concentrations of 1.5% in soil (w/w). Fourier transform infrared spectrometry revealed that the phenols and the sesquiterpene lactones that are responsible for the allelopathic impact of Lantana were largely destroyed in the course of vermicomposting. There is also an indication that lignin content of Lantana was reduced during its vermicomposting. The findings open up the possibility that the billions of tons of phytomass that is generated annually by Lantana and other invasives can be gainfully utilized in generating organic fertilizer via vermicomposting.

  3. Zebrafish Embryo Toxicity Microscale Model for Ichthyotoxicity Evaluation of Marine Natural Products.

    Science.gov (United States)

    Bai, Hong; Kong, Wen-Wen; Shao, Chang-Lun; Li, Yun; Liu, Yun-Zhang; Liu, Min; Guan, Fei-Fei; Wang, Chang-Yun

    2016-04-01

    Marine organisms often protect themselves against their predators by chemical defensive strategy. The second metabolites isolated from marine organisms and their symbiotic microbes have been proven to play a vital role in marine chemical ecology, such as ichthyotoxicity, allelopathy, and antifouling. It is well known that the microscale models for marine chemoecology assessment are urgently needed for trace quantity of marine natural products. Zebrafish model has been widely used as a microscale model in the fields of environment ecological evaluation and drug safety evaluation, but seldom reported for marine chemoecology assessment. In this work, zebrafish embryo toxicity microscale model was established for ichthyotoxicity evaluation of marine natural products by using 24-well microplate based on zebrafish embryo. Ichthyotoxicity was evaluated by observation of multiple toxicological endpoints, including coagulation egg, death, abnormal heartbeat, no spontaneous movement, delayed hatch, and malformation of the different organs during zebrafish embryogenesis periods at 24, 48, and 72 h post-fertilization (hpf). 3,4-Dichloroaniline was used as the positive control for method validation. Subsequently, the established model was applied to test the ichthyotoxic activity of the compounds isolated from corals and their symbiotic microbes and to isolate the bioactive secondary metabolites from the gorgonian Subergorgia mollis under bioassay guidance. It was suggested that zebrafish embryo toxicity microscale model is suitable for bioassay-guided isolation and preliminary bioactivity screening of marine natural products.

  4. [Inhibitory effect of Gracilaria lemaneformis (Bory) Weber Bosse on the co-cultured Scrippsiella trochoidea (Stein) Loeblich III under controlled laboratory conditions].

    Science.gov (United States)

    Zhang, Shan-dong; Song, Xiu-xian; Cao, Xi-hua; Yu, Zhi-ming

    2008-08-01

    The inhibitory effects of Grcilaria lemaneiformis on the co-cultured Scrippsiella trochoidea were determined under controlled laboratory conditions, and the possible mechanism was studied. Results showed that: (1) in the separating S. trochoiea-G. lemaneormis co-culture system when the initial cell density of C. lemaneaonis was set at 0.5 g x L(-1), the growth of S. trochoidea was obviously inhibited and its maximum cell density and exponential phase were decreased compared with the control; however, the inhibitory effect was not as strong as that in the direct cell-cell contact co-culture. Result showed that allelopathy basing on the direct cell contact was the most possible reason leading to the observed result; (2) when the initial cell density of G. lemaneiformis was set at 0.2 g'L-' in the direct cell-cell contact co-culture, the intracellular nitrate concentration of S. trochoidea in monoculture system was 1.5 times of that in co-culture. It seemed that G. lemaneiformis could competitively absorb the environmental nitrate and ultimately led to the decrease of the stock of intracellular nitrate of S. trochoidea.

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2006-02-01

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

  7. 尾巨桉纯林土壤化感效应的生物评价%Bioassay of Allelopathic Effects of Pure Forest Soil of Eucalyptus urophylla × E.grandis

    Institute of Scientific and Technical Information of China (English)

    郝建; 王凌晖; 秦武明

    2011-01-01

    用不同浓度的尾巨桉(Eucalyptus urophylla×E.grandis)纯林土壤水浸提液处理菜心(Brassica parachinensis)、白菜(B.pekineinsis)、水稻(Oryza sativa)、萝卜(Raphanus sativus)的种子和幼苗,综合评价尾巨桉纯林土壤的化感作用.结果表明,尾巨桉纯林土壤对所选作物有化感作用,浸提液浓度不同,其化感效应不同,受体植物不同,化感效应差别也较大,浓度越低化感作用越小,而随着溶液浓度的增大化感抑制作用逐渐增强.%Solutions of water extract of the soil of pure Eucalyptus urophylla × E. grandis forest were applied on the seeds and seedlings of Brassica parachinensis, B. pekinensis, Oryza sativa, and Raphanus sativus to comprehensively evaluate the allelopathic effects of the soil. Allelopathic effects of the soil to the selected crops were found, and exhibited concentration dependency. Differences in the degrees of allelopathy among different crops were also found.

  8. Interspecific variation in the allelopathic potential of the family Myrtaceae

    Directory of Open Access Journals (Sweden)

    Maristela Imatomi

    2013-03-01

    Full Text Available Allelopathy is a type of biotic interference wherein a plant releases bioactive metabolites into an environment, thereby affecting the adjacent biota. Stressful environments stimulate the production of these metabolites. The present study tests the novel weapons hypothesis, which postulates that species belonging to the same genus and from the same environment have similar allelopathic effects. The aim of this study was to assess the allelopathic effects that the aqueous leaf extracts of 15 species belonging to five genera of the Myrtaceae family have on the seed germination and initial seedling growth of lettuce (Lactuca sativa L., tomato (Solanum lycopersicum L. and onion (Allium cepa L.. Germination rates, average germination times, informational entropy of germination and allelopathic effects, as quantified with a response index, were calculated. A taxonomic distance matrix based on Gower dissimilarity and a Euclidean distance matrix were constructed. The results revealed that all extracts from donor species significantly increased average germination time or reduced the germination rate of eudicotyledonous plant species. The only extracts that showed no effect on monocotyledonous seeds were those of Campomanesia pubescens O. Berg and Psidium cinereum Mart. We conclude that eudicotyledonous and monocotyledonous plants were both significantly affected by the presence of all extracts tested. Our results make it clear that each species behaves distinctly in relation to allelopathic activity, with no apparent grouping by genus or subtribe. Therefore, the hypothesis was rejected, because plants from the same environment and with taxonomic proximity do not necessarily display similar production of secondary metabolites.

  9. The effect of environmental parameters and cyanobacterial blooms on phytoplankton dynamics of a Portuguese temperate lake

    DEFF Research Database (Denmark)

    De Figueiredo, Daniela R.; P. S. Reboleira, Ana Sofia; Antunes, Sara C.

    2006-01-01

    The increasing occurrence of cyanobacterial blooms in freshwaters is of great concern due to the ability of many cyanobacteria to produce cyanotoxins. In the present work, the eutrophied Vela Lake (Central Portugal), used for recreational purposes and as a water source for agriculture, was monito......The increasing occurrence of cyanobacterial blooms in freshwaters is of great concern due to the ability of many cyanobacteria to produce cyanotoxins. In the present work, the eutrophied Vela Lake (Central Portugal), used for recreational purposes and as a water source for agriculture...... (particularly phosphorus). Diatoms were dominant during winter months (inferior temperatures and higher nutrients availability) followed by green algae in early spring and then cyanobacteria from late spring until early autumn (less nutrient availability and higher temperatures). A massive cyanobacterial bloom...... for the phytoplanktonic assemblage during the study period was increased in about 7% achieving a total of 61.0%, indicating a correlation that may be due to the known competitive advantage and/or allelopathy of the bloom-forming cyanobacteria towards microalgae. © Springer 2006....

  10. Release from belowground enemies and shifts in root traits as interrelated drivers of alien plant invasion success: a hypothesis.

    Science.gov (United States)

    Dawson, Wayne

    2015-10-01

    Our understanding of the interrelated mechanisms driving plant invasions, such as the interplay between enemy release and resource-acquisition traits, is biased by an aboveground perspective. To address this bias, I hypothesize that plant release from belowground enemies (especially fungal pathogens) will give invasive plant species a fitness advantage in the alien range, via shifts in root traits (e.g., increased specific root length and branching intensity) that increase resource uptake and competitive ability compared to native species in the alien range, and compared to plants of the invader in its native range. Such root-trait changes could be ecological or evolutionary in nature. I explain how shifts in root traits could occur as a consequence of enemy release and contribute to invasion success of alien plants, and how they could be interrelated with other potential belowground drivers of invasion success (allelopathy, mutualist enhancement). Finally, I outline the approaches that could be taken to test whether belowground enemy release results in increased competitive ability and nutrient uptake by invasive alien plants, via changes in root traits in the alien range.

  11. Allelopathic evidence in exotic guava (Psidium guajava L.

    Directory of Open Access Journals (Sweden)

    Tatiani Elisa Chapla

    2010-12-01

    Full Text Available The allelopathic activity of the leaf aqueous extract of guava (Psidium guajava L. on seed germination and root growth in lettuce (Lactuca sativa L. was studied in an experiment consisting of four replicates with 10 seeds each and extract concentrations of 5, 10, and 20%. Guava allelopathic activity occurred during the germination and growth of lettuce roots at 20% extract concentration, as shown by ANOVA. This result suggested the allelopathic potential of the species. Therefore, the success of P. guajava in invading environments could be partially due to allelopathy. Further studies using other plant parts and field experiments should be conducted.Com a finalidade de avaliar a atividade alelopática do extrato aquoso de folha da goiabeira (Psidium guajava L. sobre a germinação e crescimento de raiz de alface (Lactuca sativa L. foi aplicado um experimento com concentrações de extrato à 5, 10 e 20%, com 4 repetições e 10 sementes cada uma. Por meio de uma ANOVA, foi verificado atividade alelopática da goiabeira sobre a germinação e crescimento da raiz de alface na concentração de 20%, indicando o potencial alelopático da espécie. Desta forma, o sucesso de Psidium guajava em invadir ambientes pode ser atribuído, em parte, à alelopatia. Recomendamos mais estudos com outras partes da planta e experimentos em campo.

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

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    Alejandro Flores-Palacios

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

  13. Investigating a Potential Auxin-Related Mode of Hormetic/Inhibitory Action of the Phytotoxin Parthenin.

    Science.gov (United States)

    Belz, Regina G

    2016-01-01

    Parthenin is a metabolite of Parthenium hysterophorus and is believed to contribute to the weed's invasiveness via allelopathy. Despite the potential of parthenin to suppress competitors, low doses stimulate plant growth. This biphasic action was hypothesized to be auxin-like and, therefore, an auxin-related mode of parthenin action was investigated using two approaches: joint action experiments with Lactuca sativa, and dose-response experiments with auxin/antiauxin-resistant Arabidopsis thaliana genotypes. The joint action approach comprised binary mixtures of subinhibitory doses of the auxin 3-indoleacetic acid (IAA) mixed with parthenin or one of three reference compounds [indole-3-butyric acid (IBA), 2,3,5-triiodobenzoic acid (TIBA), 2-(p-chlorophenoxy)-2-methylpropionic acid (PCIB)]. The reference compounds significantly interacted with IAA at all doses, but parthenin interacted only at low doses indicating that parthenin hormesis may be auxin-related, in contrast to its inhibitory action. The genetic approach investigated the response of four auxin/antiauxin-resistant mutants and a wildtype to parthenin or two reference compounds (IAA, PCIB). The responses of mutant plants to the reference compounds confirmed previous reports, but differed from the responses observed for parthenin. Parthenin stimulated and inhibited all mutants independent of resistance. This provided no indication for an auxin-related action of parthenin. Therefore, the hypothesis of an auxin-related inhibitory action of parthenin was rejected in two independent experimental approaches, while the hypothesis of an auxin-related stimulatory effect could not be rejected.

  14. 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.

  15. Biosynthesis and molecular actions of specialized 1,4-naphthoquinone natural products produced by horticultural plants

    Science.gov (United States)

    Widhalm, Joshua R; Rhodes, David

    2016-01-01

    The 1,4-naphthoquinones (1,4-NQs) are a diverse group of natural products found in every kingdom of life. Plants, including many horticultural species, collectively synthesize hundreds of specialized 1,4-NQs with ecological roles in plant–plant (allelopathy), plant–insect and plant–microbe interactions. Numerous horticultural plants producing 1,4-NQs have also served as sources of traditional medicines for hundreds of years. As a result, horticultural species have been at the forefront of many basic studies conducted to understand the metabolism and function of specialized plant 1,4-NQs. Several 1,4-NQ natural products derived from horticultural plants have also emerged as promising scaffolds for developing new drugs. In this review, the current understanding of the core metabolic pathways leading to plant 1,4-NQs is provided with additional emphasis on downstream natural products originating from horticultural species. An overview on the biochemical mechanisms of action, both from an ecological and pharmacological perspective, of 1,4-NQs derived from horticultural plants is also provided. In addition, future directions for improving basic knowledge about plant 1,4-NQ metabolism are discussed. PMID:27688890

  16. Screening Green Manure Cover Crops for their Allelopathic Effects on Some Important Weeds Found in Zimbabwe

    Directory of Open Access Journals (Sweden)

    Runzika, M.

    2013-08-01

    Full Text Available Weed control is a serious problem in smallholder conservation agriculture farming areas in Zimbabwe. Green Manure Cover Crops (GMCCs, which improve soil fertility and reduce weeds through allelopathy, are likely to reduce the cost of weed control in these areas. A laboratory study was conducted at the University of Zimbabwe to investigate the effect of extracts of eleven GMCCs on the germination percentage, radicle and plumule length of Bidens pilosa, Eleusine indica and Pennisatum glaucum (pearl millet. A green house experiment was also done to determine the allelopathic potential of these GMCC extracts applied as soil incorporated residues on the emergence and dry matter production of E. indica, B. pilosa and Acanthospermum hispidum. GMCC extracts significantly reduced germination, radicle and plumule length of Pennisatum glaucum (P < 0.05 except for Crotalaria grahamiana and Raphanus sativas which had no effect on germination of Pearl millet. The emergence and dry matter of B. pilosa, E. indica and A. hispidum were significantly reduced by these legumes (P < 0.05 with the exception of common vetch (Vicia sativa which stimulated the emergence of A. hispidum. Most of the legumes that were used in this study have allelopathic effects on B. pilosa, E. indica and A. hispidum.

  17. 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.

  18. Allelopathic effects of Knotweed (Polygonum avicular on emergence and seedling growth of tomato and corn

    Directory of Open Access Journals (Sweden)

    ebrahim kazerooni monfared

    2009-06-01

    Full Text Available In recent years, allelopathy has received special attention by scientists in integrated weed management (IWM. To study the effect of different amount of Knotweed residue on emergence and growth of tomato and corn seedlings, two experiments were conducted at Ferdowsi University of Mashhad. The type of design was completely randomized, with 5 and 4 replications for tomato and corn, respectively. The Knotweed residues (zero, 0.33, 0.67, 1 and 1.33 %( W/W were added to the pot soil. Seedlings showed different response to different amount of Knotweed residues. Increasing residues increased the emergence percentage of tomato but decreased corn emergence. Increasing residues resulted in increasing 33.9% and 39.3% of leaf area in tomato and corn, respectively. Knotweed residues resulted in 36.5% and 46.7% increase in shoot dry matter of tomato and corn, respectively. Increasing dry matter resulted in increasing up to 67.2% and 54.5% root dry matter of tomato and corn, respectively. Different doses of Knotweed had stimulatory effect on emergence of tomato but had inhibiting effect on corn. Knotweed residues had stimulating effect on seedling growth of corn and tomato. Root dry matters of both species were more influenced by Knotweed residue than foliage.

  19. Chemically-mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

    Science.gov (United States)

    Paul, Valerie J.; Kuffner, Ilsa B.; Walters, Linda J.; Ritson-Williams, Raphael; Beach, Kevin S.; Becerro, Mikel A.

    2011-01-01

    Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment.

  20. ATIVIDADE ALELOPÁTICA DE EXTRATOS DE PLANTAS DE COBERTURA SOBRE SOJA, PEPINO E ALFACE

    Directory of Open Access Journals (Sweden)

    JOSELI VIVIANE DITZEL NUNES

    2014-01-01

    Full Text Available Allelopathy can be defined as any effect , direct or indirect, beneficial or harmful, a plant on the other, through the release of chemical compounds into the environment. Thus, this study aimed at evaluat- ing, in the laboratory, allelopathic effects of aqueous extracts from cover crops as canola (Brassica napus L. var, crambe (Crambe abyssinica Hochst, sunn hemp (Crotalaria juncea, linseed (Linum usitatissimum L. and forage turnip (Raphanus sativus L. at 0, 12.5, 25, 50 and 100% concentrations. The plants used in aqueous extracts were collected during their flowering period of each studied species. Germination tests were performed on seeds gerbox, fresh and dry seedlings biomass, root and shoots seedlings length. The experimental design was completely randomized (CRD in factorial (5x5 with four replicates per treatment. According to these results, it can be concluded that the tested extracts showed allelopathic effect on seedlings of lettuce, cucumber and soybean on almost all parameters, but for soybean germination and dry mass percentage, this effect was not significant. The sunn hemp extract, despite concentration, contributed the most to increased germination and seedling growth. However, linseed extract showed opposite effect for these parameters in 100% concentrations.

  1. 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.

  2. Effets allélopathiques des Brassicacées via leurs actions sur les agents pathogènes telluriques et les mycorhizes : analyse bibliographique. Partie II

    Directory of Open Access Journals (Sweden)

    Reau Raymond

    2005-07-01

    Full Text Available Brassicas contain glucosinolates (GSL which decomposition is able to reduce the growth of populations of soil-borne fungi, bacterias or nematodes. These biocid effects on soil-borne microorganisms make a form of allelopathy phenomenon. The allelopathic properties depends on the GLS composition of the Brassicas: Indian mustard and in a lower extend Oilseed rape culd have the most powerfull action, White mustard would have a weaker action. These properties also depends on crop residues: green manure with quick decomposition would result with a higher action than crop residues after grain harvest.The main mechanisms are known. In vitro, isothiocyanates obtained from the GSL decomposition inhibit all the phases of the cycle of Aphanomyces eutiches, the fungus responsible for root rot of peas. The mycelian growth of Gaeumannomyces graminis tritici, the fungus responsible for the wheat take all is inhibited by some isothyocyanates at low concentration. Furthermore, several studies give the evidence that the incorporation of Brassicas residues into the soil does inhibit the growth of both soil-borne pathogens. At last, the presence of roots of Brassicas inhibits the germination of the mycorhizes known to improve the mineral nutrition of its host plant. This phenomenon could explain the depressive effect of oilseed rape on the nutrition of a subsequent maize.This knowledge of Brassicas effects into cropping systems offers issues for a better management of precedent effects of Brassicas; these effects being positive (integrated cop protection or negative (management of subsequent crop nutrition after Brassicas.

  3. Transformation of toxic and allelopathic lantana into a benign organic fertilizer through vermicomposting

    Science.gov (United States)

    Hussain, Naseer; Abbasi, Tasneem; Abbasi, S. A.

    2016-06-01

    In a first study of its kind, the composition of vermicompost derived solely from the toxic and allelopathic weed lantana has been investigated using UV-visible and Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) and differential scanning calorimetry (DSC), gas chromatography-mass spectometry (GC-MS), and scanning electron microscopy (SEM). The studies reveal that a sharp reduction in humification index, substantial mineralization of organic matter and degradation of complex aromatics such as lignin and polyphenols into simpler carbohydrates and lipids occur in the course of vermicomposting. GC-MS analysis shows significant fragmentation, bio-oxidation and molecular rearrangements of chemical compounds in vermicompost in comparison to those in lantana. SEM micrographs of vermicompost reflect strong disaggregation of material compared to the much better formed lantana matrices. The phenols and sesquiterpene lactones which are specifically responsible for the toxicity and allelopathy of lantana are seen to get significantly degraded in the course of vermicomposting - turning it into a plant-friendly organic fertilizer. The study leads to the possibility that the millions of tons of phytomass that is generated annually by lantana can be gainfully utilized in producing organic fertilizer via vermicomposting.

  4. 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.

  5. Differential allelopathic effects of Japanese knotweed on willow and cottonwood cuttings used in riverbank restoration techniques.

    Science.gov (United States)

    Dommanget, Fanny; Evette, André; Spiegelberger, Thomas; Gallet, Christiane; Pacé, Marine; Imbert, Marika; Navas, Marie-Laure

    2014-01-01

    Using bioengineering techniques to restore areas invaded by Fallopia japonica shows promising results. Planting tree cuttings could allow both rapidly re-establishing a competitive native plant community and reducing F. japonica performance. However, F. japonica has been shown to affect native plant species through different mechanisms such as allelopathy. This article investigates the phytotoxic effect of F. japonica on the resprouting capacity and the growth of three Salicaceae species with potential value for restoration. An experimental design which physically separates donor pots containing either an individual from F. japonica or bare soil from target pots containing cuttings of Populus nigra, Salix atrocinerea or Salix viminali was used. Leachates from donor pots were used to water target pots. The effects of leachates were evaluated by measuring the final biomass of the cuttings. F. japonica leachates inhibited the growth of cuttings, and this effect is linked to the emission of polyphenol compounds by F. japonica. Leachates also induced changes in soil nitrogen composition. These results suggest the existence of allelopathic effects, direct and/or indirect, of F. japonica on the growth of Salicaceae species cuttings. However, the three species were not equally affected, suggesting that the choice of resistant species could be crucial for restoration success.

  6. ALELOPATIA DO NIM NOS ASPECTOS FISIOLÓGICOS DA GERMINAÇÃO DE SEMENTES DE MARACUJÁ EM DISTINTOS PERÍODOS DE ARMAZENAMENTO

    Directory of Open Access Journals (Sweden)

    Naedja Nara de Araujo Neves

    2008-01-01

    Full Text Available The passion fruit tree (Passiflora edulis Sims f. flavicarpa Deg. is a fruitful tree whose the propagation usually is made for seeds. With the objective to study the possible effects allelopathy of neem in the physiologic aspects in germination of seeds of passion fruit in the different periods of storage. Was carried at UFERSA. For the acquisition of powder of neem, it was used plants located in institution. In the obtaining of seeds of passion fruits, it was used in natura fruits bought in the local supermarket; this seeds were extracted of fruits for fermentation. It was placed 50g of seeds of passion fruits together with each measure of powder of leaves of neem (0; 0,25; 0,50; 0,75; 1,0 g of powder of leaves of neem / 50 g of seeds of passion fruits. It was utilized the randomized design in esquire of portions subdivides, where the portions was composed of five dosages of powder of leaves neem.

  7. 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.

  8. The Effect of Dissolved Polyunsaturated Aldehydes on Microzooplankton Growth Rates in the Chesapeake Bay and Atlantic Coastal Waters

    Directory of Open Access Journals (Sweden)

    Peter J. Lavrentyev

    2015-05-01

    Full Text Available Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA. Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists on their impact on key herbivores in the ocean, microzooplankton. This study examined the effects of dissolved 2E,4E-octadienal and 2E,4E-heptadienal on the growth rates of natural ciliate and dinoflagellate populations in the Chesapeake Bay and the coastal Atlantic waters. The overall effect of PUA on microzooplankton growth was negative, especially at the higher concentrations, but there were pronounced differences in response among common planktonic species. For example, the growth of Codonella sp., Leegaardiella sol, Prorodon sp., and Gyrodinium spirale was impaired at 2 nM, whereas Strombidium conicum, Cyclotrichium gigas, and Gymnodinium sp. were not affected even at 20 nM. These results indicate that PUA can induce changes in microzooplankton dynamics and species composition.

  9. Allelopathic Potential of Switchgrass ( Panicum virgatum L.) on Perennial Ryegrass ( Lolium perenne L.) and Alfalfa ( Medicago sativa L.)

    Science.gov (United States)

    Shui, Junfeng; An, Yu; Ma, Yongqing; Ichizen, Nobumasa

    2010-10-01

    This study investigated allelopathy and its chemical basis in nine switchgrass ( Panicum virgatum L.) accessions. Perennial ryegrass ( Lolium perenne L.) and alfalfa ( Medicago sativa L.) were used as test species. Undiluted aqueous extracts (5 g plant tissue in 50 ml water) from the shoots and roots of most of the switchgrass accessions inhibited the germination and growth of the test species. However, the allelopathic effect of switchgrass declined when extracts were diluted 5- or 50-fold. Seedling growth was more sensitive than seed germination as an indicator of allelopathic effect. Allelopathic effect was related to switchgrass ecotype but not related to ploidy level. Upland accessions displayed stronger allelopathic potential than lowland accessions. The aqueous extract from one switchgrass accession was separated into phenols, organic acids, neutral chemicals, and alkaloids, and then these fractions were bioassayed to test for allelopathic potential. Alkaloids had the strongest allelopathic effect among the four chemical fractions. In summary, the results indicated that switchgrass has allelopathic potential; however, there is not enough evidence to conclude that allelopathic advantage is the main factor that has contributed to the successful establishment of switchgrass on China’s Loess Plateau.

  10. Effets allélopathiques des Brassicacées via leurs actions sur les agents pathogènes telluriques et les mycorhizes : analyse bibliographique. Partie 1

    Directory of Open Access Journals (Sweden)

    Reau Raymond

    2005-05-01

    Full Text Available Brassicas contain glucosinolates (GSL which decomposition is able to reduce the growth of populations of soil-borne fungi, bacterias or nematodes. These biocid effects on soil-borne microorganisms make a form of allelopathy phenomenon. The allelopathic properties depends on the GLS composition of the Brassicas: Indian mustard and in a lower extend Oilseed rape could have the most powerfull action, White mustard would have a weaker action. These properties also depends on crop residues: green manure with quick decomposition would result with a higher action than crop residues after grain harvest. The main mechanisms are known. In vitro, isothiocyanates obtained from the GSL decomposition inhibit all the phases of the cycle of Aphanomyces eutiches, the fungus responsible for root rot of peas. The mycelian growth of Gaeumannomyces graminis tritici, the fungus responsible for the wheat take all is inhibited by some isothyocyanates at low concentration. Furthermore, several studies give the evidence that the incorporation of Brassicas residues into the soil does inhibit the growth of both soil-borne pathogens. At last, the presence of roots of Brassicas inhibits the germination of the mycorhizes known to improve the mineral nutrition of its host plant. This phenomenon could explain the depressive effect of oilseed rape on the nutrition of a subsequent maize. This knowledge of Brassicas effects into cropping systems offers issues for a better management of precedent effects of Brassicas; these effects being positive (integrated cop protection or negative (management of subsequent crop nutrition after Brassicas.

  11. Study of freshwater red tide control measures; Tansui akashio taisaku ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, M.; Hatamochi, K. [Kansai Electric Power Co. Inc., Osaka (Japan)

    1997-09-30

    Basic research of biological measures for which the accumulation of basic findings is mandatory and the applied research of chemical and physical measures that are higher in feasibility are conducted for the establishment of measures to counter freshwater red tides. In the basic research, natural enemies, algaecidal microbes, conjugation inhibiting substances, and allelopathy are studied, but none of them is found feasible at the current stage. In the basic research, however, factors are discovered that inhibit the multiplication of Peridinium bipes or perish the same. In the applied research, chemical algaecidal methods, UV-aided algaecidal methods, and various red-tide constituent collection methods are studied. Collection methods are compared, and it is concluded that a method of Toray Industries, Inc., efficiently collects red-tide constituents. In this method, red-tide constituents are screened by and condensed on a cloth filter provided on the internal wall of a drum, and are dehydrated and then transferred. The applied research further involves the prediction of red tide outbreak and the raising of fish on a food containing substances extracted from red tides, and it is suggested that these are feasible. 18 refs., 15 figs., 3 tabs.

  12. Competition for one nutrient with internal storage and toxin mortality.

    Science.gov (United States)

    Grover, James P; Wang, Feng-Bin

    2013-08-01

    This study presents a mathematical model of two species competing in a chemostat for one resource that is stored internally, and who also compete through allelopathy. Each species produces a toxin to that increases mortality rate of its competitor. The two species system and its single species subsystem follow mass conservation constraints characteristic of chemostat models. Persistence of a single species occurs if the nutrient supply of an empty habitat allows it to acquire a threshold of stored nutrient quota, sufficient to overcome loss to outflow after accounting for the cost of toxin production. For the two-species system, a semitrivial equilibrium with one species resident is unstable to invasion by the missing species according to a similar threshold condition. The invader increases if acquires a stored nutrient quota sufficient to overcome loss to outflow and toxin-induced mortality, after accounting for the cost of the invader's own toxin production. If both semitrivial equilibria for the two-species system are invasible then there is at least one coexistence equilibrium. Numerical analyses indicate another possibility: bistability in which both semitrivial equilibria are stable against invasion. In such a case there is competitive exclusion of one species, whose identity depends on initial conditions. When there is a tradeoff between abilities to compete for the nutrient and to compete through toxicity, the more toxic species can dominate only under nutrient-rich conditions. Bistability under such conditions could contribute to the unpredictability of toxic algal blooms.

  13. Chemically mediated interactions between macroalgae Dictyota spp. and multiple life-history stages of the coral Porites astreoides

    Science.gov (United States)

    Paul, V.J.; Kuffner, I.B.; Walters, L.J.; Ritson-Williams, R.; Beach, K.S.; Becerro, M.A.

    2011-01-01

    Competition between corals and macroalgae is often assumed to occur on reefs, especially those that have undergone shifts from coral to algal dominance; however, data examining these competitive interactions, especially during the early life-history stages of corals, are scarce. We conducted a series of field and outdoor seawater-table experiments to test the hypothesis that allelopathy (chemical inhibition) mediates interactions between 2 common brown macroalgae, Dictyota pulchella and D. pinnatifida, and the coral Porites astreoides at different life-history stages of the coral. D. pinnatifida significantly reduced larval survival and larval recruitment. The extracts of both D. pinnatifida and D. pulchella significantly reduced larval survival, and the extract of D. pulchella also negatively influenced larval recruitment. There was no measurable effect of the crude extracts from Dictyota spp. on the photophysiology of adult corals. Our results provide evidence that these Dictyota species chemically compete with P. astreoides by negatively affecting larval settlement and recruitment as well as the survival of larvae and new recruits. Macroalgae may perpetuate their dominance on degraded reefs by chemically inhibiting the process of coral recruitment. ?? 2011 Inter-Research.

  14. An allelopathic substance in red pine needles (Pinus densiflora).

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Fushimi, Yoshiko; Shigemori, Hideyuki

    2009-03-01

    Aqueous methanol extracts of red pine (Pinus densiflora) needles inhibited the growth of roots and shoots of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), ryegrass (Lolium multiflorum), timothy (Pheleum pratense), Digitaria sanguinalis and Echinochloa crus-galli. Increasing the extract concentration increased inhibition, suggesting that the pine needles may have growth inhibitory substances and possess allelopathic potential. The aqueous methanol extract of the pine needles was purified, and a main inhibitory substance was isolated and determined by spectral data as 9alpha,13beta-epidioxyabeit-8(14)en-18-oic acid. This substance inhibited root and shoot growth of cress and Echinochloa crus-galli seedlings at concentrations greater than 0.1 mM. The endogenous concentration of the substance was 0.13 mmol/kg pine needle. These results suggest that 9alpha,13beta-epidioxyabeit-8(14)en-18-oic acid may contribute to the growth inhibitory effect of the pine needles and may play an important role in the allelopathy of red pine.

  15. Interactions between Ipomoea aquatica and Microbial Populations

    Institute of Scientific and Technical Information of China (English)

    Kan; Yuanqing; Sun; Ling; Zhang; Ying

    2014-01-01

    [Objective]This paper was to research the water purification mechanism of Ipomoea aquatica and its correlation with algae and rotifer. [Methods]Taking I. aquatica as the test material,Chlorella vulgaris,Scenedesmus obliquus,Microcystis aeroginosa and rotifer Adineta vaga with different densities were added to the hydroponics nutrients solutions of I. aquatica by the hydroponic ecological simulation method. The growth characteristics of I. aquatica,changes of microbial populations and the consumption status of nutrients in the nutritional solution were determined. And the interactions between the plant and the microbial populations were researched. [Results]When I. aquatica seedlings grew to a certain stage,growth of principal root stopped; while the lateral roots emerged greatly; and the nutrition absorption efficiency enhanced. As the inoculation concentration of C. vulgaris increased,root length of I. aquatica increased relatively great due to the competition for nutrients. The competition and allelopathy of M. aeroginosa and S. obliquus restricted the development of root system of I. aquatica. The grazing pressure of Chlorella vulgaris had little effects on M. aeroginosa,but restricted the rapid growth of S. obliquus. [Conclusions]This research provided data support for the application of fish-shrimp-vegetable aquaculture system.

  16. Effects of Allelochemicals from Ficus microcarpaon Chlorella pyrenoidosa

    Directory of Open Access Journals (Sweden)

    Zhongyang Jiang

    2014-08-01

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

  17. How do bryophytes govern generative recruitment of vascular plants?

    Science.gov (United States)

    Soudzilovskaia, Nadejda A; Graae, Bente J; Douma, Jacob C; Grau, Oriol; Milbau, Ann; Shevtsova, Anna; Wolters, Loes; Cornelissen, Johannes H C

    2011-06-01

    Interactions between vascular plants and bryophytes determine plant community composition in many ecosystems. Yet, little is known about the importance of interspecific differences between bryophytes with respect to their effects on vascular plants. We compared the extent to which species-specific bryophyte effects on vascular plant generative recruitment depend on the following underlying mechanisms: allelopathy, mechanical obstruction, soil moisture and temperature control. We sowed 10 vascular plant species into monospecific mats of six chemically and structurally diverse bryophytes, and examined 1-yr seedling recruitment. Allelopathic effects were also assessed in a laboratory phyto-assay. Although all bryophytes suppressed vascular plant regeneration, there were significant differences between the bryophyte species. The lack of interactions indicated the absence of species-specific adaptations of vascular plants for recruitment in bryophyte mats. Differences between bryophyte species were best explained by alterations in temperature regime under bryophyte mats, mostly by reduced temperature amplitudes during germination. The temperature regime under bryophyte mats was well predicted by species-specific bryophyte cushion thickness. The fitness of established seedlings was not affected by the presence of bryophytes. Our results suggest that climatically or anthropogenically driven changes in the species' composition of bryophyte communities have knock-on effects on vascular plant populations via generative reproduction.

  18. Allelopathic effects of essential oil from Eucalyptus grandis × E.urophylla on pathogenic fungi and pest insects

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This study on the allelopathic effects and chemical components of the essential oil from Eucalyptus grandis × E.urophylla shows that the leaf oil emulsion of E.grandis × E.urophylla can inhibit the proliferation of pathogenic fungi Fusarium oxysporum,Pyriculerie grisea,Glorosprium musa rum and Phytophthora capsici.Pupation and feeding of the pest insects Spodopteralitura Fabricius and Helicoverpa armigera Hubner are shown to be affected with restraining effects which increase with the increasing levels of oil concentration.A GC/MS analysis of the leaf oil indicated that the main components,with a relative content of≥3%,were alloocimene (43.22%),α-pinene (13.63%),γ-terpinene (5.49%),(E)-3,7-dimethyl-2,6-octadien-1-ol (3.58%),β-fenchyl alcohol (4.58%),and 2-amino-3,5-dicyano-6-(4-methoxyphenoxy)-pyridine (3.67%).Terpenes played an important role in the inhibitory effects of E.grandis × E.urophylla essential oil on pathogenic fungi and pest insects.Poor biodiversity of eucalyptus plantations is a function of allelopathy.

  19. 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

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

    Institute of Scientific and Technical Information of China (English)

    周健; 马丹炜; 陈永甜; 袁立娜; 黄雪婷; 瞿欢欢

    2016-01-01

    化感作用是外来植物土荆芥( Chenopodium ambrosioides)成功入侵的机制之一。为了探讨土荆芥挥发油的化感作用机制,该文以蚕豆( Vicia faba)叶的下表皮为材料,将表皮条孵育在分别含土荆芥挥发油、α-萜品烯和对伞花素的MES [2-( N-morpholino) ethanesulfonic acid]缓冲液中,25℃下光照培养30 min,采用吖啶橙/溴乙锭( AO/EB)双荧光染色法和Feulgen染色法,研究土荆芥挥发油、α-萜品烯和对伞花素对保卫细胞活性和细胞核形态的影响。结果表明:在土荆芥挥发油、α-萜品烯和对伞花素的作用下,蚕豆气孔保卫细胞活性降低,细胞核出现固缩、畸形或降解等细胞凋亡特征。随着处理剂量增加,保卫细胞活性显著下降,核异常率显著增加,表明土荆芥挥发油、α-萜品烯和对伞花素均对蚕豆保卫细胞具有细胞毒性,其中,挥发油毒性最大,α-萜品烯的毒性次之,对伞花素的毒性最小;Caspase抑制剂Z-VAD-FMK可缓解挥发油、α-萜品烯和对伞花素对保卫细胞的毒性,提高细胞活性,这种缓解效应随着抑制剂浓度的增加而增大。由此可见,土荆芥挥发油、α-萜品烯和对伞花素诱导蚕豆保卫细胞发生了Caspase依赖性的细胞凋亡。%Chenopodium ambrosioides, an aromatic herbnative to tropical Central and South America, has become a major invasive plant in China. Allelopathy plays a crictical role in the successful invasion of C. ambrosioides, and has an allelopathic stress on neighbor plants. To explore the allelopathy mechanism, the effects of volatile oil from C. am-brosioides,α-terpinene and cymene on guard cell viabilities and nucleus morphology in Vicia faba leaves were investi-gated using epidermal strips bioassay, AO/EB fluorescent staining and conventional Feulgen staining. Epidermal strips of leaves were incubated in 2-( N-morpholino) ethanesulfonic acid ( MES) buffer containing volatile oil, α-terpinene and cymene for

  1. 干旱胁迫与外源激素PDJ对不同基因型小麦化感潜力的诱导调控%Inducible regulation of allelopathic potential in different wheat genetypes under drought and prohydrojasmon (PDJ) treatment

    Institute of Scientific and Technical Information of China (English)

    支金虎; 马永清; 左胜鹏

    2009-01-01

    盆载条件下对4个不同基因型小麦品种于播种前以外源激素PDJ(10 mg·L~(-1))浸种处理和返青期始干旱胁迫,测定其光合特性、水分利用和化感抗草差异.结果表明:水分胁迫(田间持水量的45%)和PDJ处理均能增强几种供试小麦的化感抗草诱导效应,两者均通过降低杂草生物量从而抑制杂草生长.水分胁迫和PDJ处理均能增强"兰考95-25"、"小偃6号"拔节期的叶片光合速率,降低气孔限制值和提高水分利用率;"豫麦66"PDJ处理下可增强光合作用而降低水分利用率,但干旱胁迫下则相反;"兰考217"经PDJ处理光合速率和水分利用率均降低.典范对应分析发现供试小麦受到干旱胁迫和外源激素PDJ处理后会引起植物形态和光合生理的变化,从而影响其化感抗草特性.小麦整体化感潜势与以杂草生物量(杂草鲜重/盆)表示的抗草指标显著相关,而小麦的整体抗草特性主要与其水分利用率、光合速率和蒸腾速率显著正相关,与植物地上生物量、株高、节间距离和气孔导度显著负相关.%In a pot experiment, growth adaptation of four winter wheat (Triticum aestivum L.) accessions was investigated following seed pretreatment by soaking with prohydrojasmon (a kind of exogenous hormone at 10 mg · L~(-1)) before sowing. The seeds were subjected to artificial soil water regulation at 75% and 45% field capacity at the start of greening. Also in the experiment, the photosynthesis level, water use, variation of weed-controlling effect of allelopathy of wheat under acclimatized soil water and PDJ treatment was conducted. Soil drought and PDJ were used to stimulate the overall allelopathic inhibition and weed-resistance of wheat in the pot trial. The study shows that physiological response of "Lankao 95-25" and "Xiaoyan 6" to water shortage and PDJ is significant due to enhanced leaf net photosynthetic rate, water use efficiency and stoma capacity. Under PDJ

  2. Efeito de cascas de café e de arroz dispostas nas camadas do solo sobre a germinação e o crescimento inicial do caruru-de-mancha Allelopathic effect of coffee and rice husks arranged in soil layers on the germination and initial growth of Amaranthus viridis

    Directory of Open Access Journals (Sweden)

    J.C.F. Santos

    2001-08-01

    Full Text Available Estudos dos efeitos dos resíduos de plantas pela utilização de coberturas mortas no controle das plantas daninhas têm apresentado dificuldade de determinar a diferenciação entre alelopatia e competição. Atualmente, muitas pesquisas têm se referido a critérios que propõem evidência à alelopatia. Este trabalho em casa de vegetação visou determinar os efeitos alelopáticos proporcionados pelas cascas de café e de arroz sobre o caruru-de-mancha, por meio das disposições desses resíduos nas camadas do solo. O delineamento experimental foi o de blocos casualizados, com os tratamentos em quatro repetições e organizados num esquema fatorial (3x3, sendo cascas de café e de arroz e vermiculita expandida como um fator e suas disposições, com resíduos depositados no topo, incorporados na superfície e incorporados no fundo, como segundo fator. Como testemunha foi usado um tratamento adicional sem cobertura. De modo geral, resíduos de cascas proporcionaram inibição da germinação e estímulo ao crescimento do caruru-de-mancha. A casca de arroz proporcionou menor índice de velocidade de emergência e germinação de sementes do que a casca de café. A casca de café depositada no topo proporcionou maior crescimento e maior peso da matéria seca do caruru-de-mancha, seguido pela mesma casca incorporada na superfície do solo.Studies of plant residue effects involving mulches to control weeds in perennial crops are difficult to carry out due to the need to differentiate between allelopathy and competition. Many researches, nowadays, refer to criteria proving allelopathy. This work was established under greenhouse conditions to determine the allelopathic effects of coffee and rice husks on Amaranthus viridis through their arrangements in soil layers. The experimental design was a randomized block with four replications, arranged in a 3 x 3 factorial scheme, with coffee and rice husks and expanded vermiculite being one factor and

  3. Activity of Hydroxamic Acids from Secale cereale Against the Plant-Parasitic Nematodes Meloidogyne incognita and Xiphinema americanum.

    Science.gov (United States)

    Zasada, I A; Meyer, S L F; Halbrendt, J M; Rice, C

    2005-10-01

    ABSTRACT Cyclic hydroxamic acids are secondary metabolites found in the family Poaceae and have been implicated in the allelopathy of rye (Secale cereale). The toxicity of these compounds against plant-parasitic nematodes is unknown. DIBOA (2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one), DIMBOA (2,4-hydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one), and their degradation products BOA (benzoxazolin-2(3H)-one) and MBOA (6-methoxy-benzoxazolin-2(3H)-one) were screened in vitro against Meloidogyne incognita second-stage juveniles (J2) and eggs and mixed-stages of Xiphinema americanum. Xiphinema americanum was more sensitive to DIBOA and DIMBOA than M. incognita J2, with a maximum apparent mortality of 96 and 92% compared to 73 and 72% at 90 mug/ml. Eggs of M. incognita were less sensitive to the hydroxamic acids than J2; only DIBOA resulted in a 50% reduction in egg hatch, with a lethal concentration (LC(50)) of 74 mug/ml compared to 21 mug/ml for J2. When M. incognita J2 were exposed to DIBOA for 48 h and the compound was removed and replaced with water, the LC(50) value increased from 21.0 to 40.7 mug/ml. MBOA was not toxic to X. americanum or M. incognita eggs, but was toxic to M. incognita J2, with LC(50) values of 44 and 20 mug/ml before and after the compound was removed and replaced with water. BOA was the least toxic hydroxamic acid tested; it did not reduce M. incognita egg hatch after 1 week of exposure or increase X. americanum mortality after 24 h of exposure. While in vitro studies provide a valuable starting point in determining the toxicity of the chemical component of rye, the relevance of the data to soil remains to be determined.

  4. ENHANCEMENT OF NUTRITIONAL QUALITY OF WHEAT (TRITICUM AESTIVUM BY METABOLIC ENGINEERING OF ISOFLAVONE PATHWAY

    Directory of Open Access Journals (Sweden)

    Ahmed Mohamed El-Shehawi

    2013-01-01

    Full Text Available Isoflavones are large group of secondary metabolites produced in legumes such as soybeans. They have essential biological functions as nutraceutical and health functions for human. They are involved in plant resistance to biotic and abiotic stresses, symbiotic relationship with nitrogen-fixing organisms and plant competition (allelopathy. In this report, isoflavonoids were expressed in wheat (Triticum aestivum via introducing the key enzymes Isoflavone Synthase (IFS. Transgenic callli induced from wheat immature embryos were propagated and prepared for bombardment. Five gene constructs were prepared; the binary vector (plasmid pAHC25, 35S-CRC, 35S-IFS, Oleocin-IFS, Oleocin-IFS-CHI and were used for wheat calli transformation. Putative transgenic calli were used to regenerate transgenic wheat plants. Evaluation of recovered transgenic plants was carried out using PCR, southern bloting of PCR products and IFS-specific probe and HPLC analysis of transgenic plant tissue extracts. Genistein and naranigenin were detected in transgenic plants carrying IFS gene, indicating that the introduced IFS was able to use the endogenous substrate from wheat. IFS showed activity under 35S promoter as well as oleocin promoter. The activity of oleocin promoter in monocots provides a good tool to use plant promoters to drive plant gene expression in plants. This also represents promoter compatibility that the cis acting elements of the oleocin promoter represent binding targets for trans acting elements of wheat. Engineering the isoflavone pathway in wheat would lead to enhancement of nutraceutical value of wheat grains and improvement of wheat resistance to diseases.

  5. Complex effects of fertilization on plant and herbivore performance in the presence of a plant competitor and activated carbon.

    Directory of Open Access Journals (Sweden)

    Nafiseh Mahdavi-Arab

    Full Text Available Plant-herbivore interactions are influenced by host plant quality which in turn is affected by plant growth conditions. Competition is the major biotic and nutrient availability a major abiotic component of a plant's growth environment. Yet, surprisingly few studies have investigated impacts of competition and nutrient availability on herbivore performance and reciprocal herbivore effects on plants. We studied growth of the specialist aphid, Macrosiphoniella tanacetaria, and its host plant tansy, Tanacetum vulgare, under experimental addition of inorganic and organic fertilizer crossed with competition by goldenrod, Solidago canadensis. Because of evidence that competition by goldenrod is mediated by allelopathic compounds, we also added a treatment with activated carbon. Results showed that fertilization increased, and competition with goldenrod decreased, plant biomass, but this was likely mediated by resource competition. There was no evidence from the activated carbon treatment that allelopathy played a role which instead had a fertilizing effect. Aphid performance increased with higher plant biomass and depended on plant growth conditions, with fertilization and AC increasing, and plant competition decreasing aphid numbers. Feedbacks of aphids on plant performance interacted with plant growth conditions in complex ways depending on the relative magnitude of the effects on plant biomass and aphid numbers. In the basic fertilization treatment, tansy plants profited from increased nutrient availability by accumulating more biomass than they lost due to an increased number of aphids under fertilization. When adding additional fertilizer, aphid numbers increased so high that tansy plants suffered and showed reduced biomass compared with controls without aphids. Thus, the ecological cost of an infestation with aphids depends on the balance of effects of growth conditions on plant and herbivore performance. These results emphasize the importance

  6. Complex effects of fertilization on plant and herbivore performance in the presence of a plant competitor and activated carbon.

    Science.gov (United States)

    Mahdavi-Arab, Nafiseh; Meyer, Sebastian T; Mehrparvar, Mohsen; Weisser, Wolfgang W

    2014-01-01

    Plant-herbivore interactions are influenced by host plant quality which in turn is affected by plant growth conditions. Competition is the major biotic and nutrient availability a major abiotic component of a plant's growth environment. Yet, surprisingly few studies have investigated impacts of competition and nutrient availability on herbivore performance and reciprocal herbivore effects on plants. We studied growth of the specialist aphid, Macrosiphoniella tanacetaria, and its host plant tansy, Tanacetum vulgare, under experimental addition of inorganic and organic fertilizer crossed with competition by goldenrod, Solidago canadensis. Because of evidence that competition by goldenrod is mediated by allelopathic compounds, we also added a treatment with activated carbon. Results showed that fertilization increased, and competition with goldenrod decreased, plant biomass, but this was likely mediated by resource competition. There was no evidence from the activated carbon treatment that allelopathy played a role which instead had a fertilizing effect. Aphid performance increased with higher plant biomass and depended on plant growth conditions, with fertilization and AC increasing, and plant competition decreasing aphid numbers. Feedbacks of aphids on plant performance interacted with plant growth conditions in complex ways depending on the relative magnitude of the effects on plant biomass and aphid numbers. In the basic fertilization treatment, tansy plants profited from increased nutrient availability by accumulating more biomass than they lost due to an increased number of aphids under fertilization. When adding additional fertilizer, aphid numbers increased so high that tansy plants suffered and showed reduced biomass compared with controls without aphids. Thus, the ecological cost of an infestation with aphids depends on the balance of effects of growth conditions on plant and herbivore performance. These results emphasize the importance to investigate both

  7. Establishment and persistence of common ragweed (Ambrosia artemisiifolia L.) in disturbed soil as a function of an urban-rural macro-environment

    Energy Technology Data Exchange (ETDEWEB)

    ZISKA, L. H.; GEORGE, K.; FRENZ, D. A.

    2006-09-28

    No data are available on whether rising carbon dioxide concentration [CO2] or increased air temperature can alter the establishment and persistence of common ragweed (Ambrosia artemisiifolia L.) within a plant community following soil disturbance. To determine ragweed longevity, we exposed disturbed soil with a common seed bank population to an in situ temperature and [CO2] gradient along an urban-rural transect beginning in early 2002. No other consistent differences in meteorological variables (e.g. wind speed, humidity, PAR, tropospheric ozone) as a function of urbanization were documented over the course of the study (2002-2005). Above-ground measurements of biomass over this period demonstrated that ragweed along the transect responded to urban induced increases in [CO2]/temperature with peak biomass being observed at this location by the end of 2003. However, by the Fall of 2004, and continuing through 2005, urban ragweed populations had dwindled to a few plants. The temporal decline in ragweed populations was not associated with increased disease, herbivory or auto-allelopathy, but was part of a demographic reduction in the total number of annual plant species observed for the urban location. In a separate experiment, we showed that such a demographic shift is consistent with CO2/temperature induced increases in biomass and litter accumulation, with a subsequent reduction in germination / survival of annual plant species. Overall, these data indicate that [CO2]/temperature differences associated with urbanization may increase initial ragweed productivity and pollen production, but suggest that long-term, multi-year persistence of ragweed in the urban macro-environment may be dependent on other factors.

  8. 我国桉树人工林现状及可持续经营对策研究%Current Situation and Sustainable Management Strategy of Eucalypt Plantations in China

    Institute of Scientific and Technical Information of China (English)

    王志超; 杜阿朋; 陈少雄

    2012-01-01

    本文阐述了目前桉树人工林的发展现状及人工林存在的稳定性差、生物多样性小、养分水分消耗过度、地力衰退、病虫害以及化感等生态问题,以及人工林经营中存在的若干问题,提出通过改良桉树人工林栽培、育种、森林经理等措施,建立可持续的遗传育种策略和桉树人工林可持续经营的技术体系,为我国桉树速生丰产林的可持续经营提供科学依据。%This paper expounds research progress and ecological challenges facing eucalypt plantations in Chi- na. Key problems discussed include poor stability, reduced biodiversity, inappropriate water and nutrient con- sumption, soil degradation, increasing pest and disease issues ; and plant allelopathy. In addition, some prob- lems in plantation operations are also revealed. From our study of these issues, suggestions are provided on how to improve the ecological situation for such plantations and these include: improvement of euca/ypt planta- tion land preparation and inter- rotation practices, enhanced silviculture and advancing genetic improve- ment. We conclude that fast - growing eucalypt plantation management in China needs to adopt a more scientif- ic approach in order to ensure both business and environmental sustainability will be achievable in the future for the benefit of China.

  9. 黄花菜根水浸提液对莴苣化感作用的初步研究%Allelopathic Study on Aqueous Extract From Daylily Root Plant on Lettuce

    Institute of Scientific and Technical Information of China (English)

    范适; 宋光桃; 刘飞渡; 郭锐

    2016-01-01

    Allelopathy of daylily root plant were studied by measuring the seed germination and seed-ling growth with lettuce watered with the aqueous extract of daylily root plant.The results were following:when concentration of 5 mg/mL, daylily root plant aqueous extract has strong stimualting effect on the seedling shoot length of lettuce,and inhibited the seed germination rate,germination index,seedling root length of lettuce;when concentration of 10 mg/mL,15 mg/mL and 20 mg/mL daylily root plant aqueous extract significanthy inhibited the seed germination rate,germination index,seedling root length and shoot length of lettuce.4figs.,1tabs,15refs.%以莴苣作为受体,通过测定黄花菜根水浸提液对莴苣种子萌发和幼苗生长的影响,对黄花菜化感物质进行了研究.结果表明:浓度为5 mg/mL时,黄花菜根水浸提液对莴苣幼苗苗长表现为促进作用,对莴苣发芽率,发芽指数,根长表现为抑制作用;浓度为10、15和20 mg/mL时,黄花菜根水浸提液对莴苣发芽率,发芽指数,根长和幼苗苗长均表现为抑制作用.图4,表1,参15.

  10. 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

    as small freshwater ponds may help to design innovative allelopathy-based aquatic ecotechnologies.

  11. Ryecyanatines A and B and ryecarbonitrilines A and B, substituted cyanatophenol, cyanatobenzo[1,3]dioxole, and benzo[1,3]dioxolecarbonitriles from rye (Secale cereale L.) root exudates: Novel metabolites with allelopathic activity on Orobanche seed germination and radicle growth.

    Science.gov (United States)

    Cimmino, Alessio; Fernández-Aparicio, Mónica; Avolio, Fabiana; Yoneyama, Koichi; Rubiales, Diego; Evidente, Antonio

    2015-01-01

    Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which represent serious weed problems causing heavy yield losses on important crops. Current control relies on the use of certain agronomic practices, resistant crop varieties, and herbicides, albeit success has been marginal. Agronomic practices such as the use of allelopathic species in intercropping or cover crops, or the use of direct seedling over residues of allelopathic species incorporate the principle of allelopathy exerted by molecules exuded from roots or released by crop residues to control broomrapes. In addition, the isolation of natural substances from root exudates of plants with potential to inhibit broomrape development opens the door to the design of new herbicides based on natural and benign sources. Ryecyanatines A and B and ryecarbonitrilines A and B, the first new substituted cyanatophenol, substituted cyanatobenzo[1,3]dioxole, and the latter two new substituted benzo[1,3]dioxolecarbonitriles were isolated from rye (Secale cereale L.) root exudates. They were characterized as 4-cyanato-2-methoxyphenol, 2-cyanato-benzo[1,3]dioxole, 2-methoxybenzo[1,3]dioxole-5-carbonitrile and benzo[1,3]dioxole-2-carbonitrile by spectroscopic (essentially NMR and HRESI MS spectra) methods. These compounds were investigated for allelopathic activity on Orobanche germination and development. Ryecarbonitriline A induced germination of Orobanche cumana seeds, and this germination can be considered as suicidal because O. cumana does not parasite rye roots and cannot survive without host resources beyond germination stage. In addition, ryecyanatine A promotes a rapid cessation of O. cumana, Orobanche crenata and Orobanche minor radicle growth with the promotion of a layer of papillae at the radicle tip in O. cumana and O. crenata hampering the contact of the parasite to the host. Ryecarbonitriline B also displayed the same activity although being less active than ryecyanatine A and

  12. Vermicomposting eliminates the toxicity of Lantana (Lantana camara) and turns it into a plant friendly organic fertilizer

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, N.; Abbasi, Tasneem; Abbasi, S.A., E-mail: prof.s.a.abbasi@gmail.com

    2015-11-15

    Highlights: • It is shown for the first time that Lantana can lose its toxicity when vermicomposted. • The Lantana vermicompost is shown to be a good organic fertilizer. • FTIR studies identified Lantana’s toxic constituents destroyed by vermicomposting. • The findings have far-reaching implications in the gainful use of harmful weeds. - Abstract: In evidently the first study of its kind, vermicompost derived solely from a weed known to possess plant and animal toxicity was used to assess its impact on the germination and early growth of several plant species. No pre-composting or supplementation of animal manure was done to generate the vermicompost in order to ensure that the impact is clearly attributable to the weed. Whereas the weed used in this study, Lantana (Lantana camara), is known to possess strong negative allelopathy, besides plant/animal toxicity in other forms, its vermicompost was seen to be a good organic fertilizer as it increased germination success and encouraged growth of all the three botanical species explored by the authors – green gram (Vigna radiata), ladies finger (Abelmoschus esculentus) and cucumber (Cucumis sativus). In terms of several physical, chemical and biochemical attributes that were studied, the vermicompost appeared plant-friendly, giving best results in general when employed at concentrations of 1.5% in soil (w/w). Fourier transform infrared spectrometry revealed that the phenols and the sesquiterpene lactones that are responsible for the allelopathic impact of Lantana were largely destroyed in the course of vermicomposting. There is also an indication that lignin content of Lantana was reduced during its vermicomposting. The findings open up the possibility that the billions of tons of phytomass that is generated annually by Lantana and other invasives can be gainfully utilized in generating organic fertilizer via vermicomposting.

  13. Uptake and translocation of phytochemical 2-benzoxazolinone (BOA) in radish seeds and seedlings.

    Science.gov (United States)

    Chiapusio, Geneviève; Pellissier, François; Gallet, Christiane

    2004-07-01

    The molecular aspects of phytochemical interactions between plants, especially the process of phytochemical translocation by the target plant, remain challenging for those studying allelopathy. 2-Benzoxazolinone (BOA) is a natural chemical produced by rye (Secale cereale) and is known to have phytotoxic effects on weed seeds and seedlings. The translocation of BOA into target plants has been poorly investigated. Therefore, the total absorption of [ring U 14C] BOA was estimated by oxidizing whole seedlings of Raphanus sativus cv. for 8 days and quantifying the radioactivity. Non-radiolabelled BOA in seedlings was also estimated by HPLC. BOA applied at 10(-3) M was readily taken up by germinated radish at a rate of 1556 nmol g(-1) FW. At these same concentrations, BOA reduced radish germination by 50% and caused a delay in radicle elongation. Exogenous BOA was responsible for the observed germination inhibition. At a concentration of 10(-5) M, BOA was taken up by germinated seeds (31 nmol g(-1) FW), but this quantity did not affect radish germination. Labelled BOA was not mineralized in the culture medium during seedling growth as no 14CO2 was recovered. Both 10(-3) and 10(-5) M BOA were translocated into radish organs, mainly into roots and cotyledons. These organs were then identified as potential physiological target sites. Cotyledons remained the target sink (44% of the total radioactivity). The kinetics of BOA uptake at 10(-3) and 10(-5) M in radish seedlings was identical: BOA accumulation was proportional to its initial concentration. A comparison between radioactivity and HPLC quantification for 10(-3) M BOA indicated that BOA (along with some metabolites) could effectively be recovered in radish organs using chromatography.

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

    Directory of Open Access Journals (Sweden)

    Motamedi Marzieh

    2016-12-01

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

  15. The impact of Pinus halepensis afforestation on Mediterranean spontaneous vegetation: do soil treatment and canopy cover matter?

    Institute of Scientific and Technical Information of China (English)

    Pasta Salvatore; Tommaso La Mantia; Juliane Rühl

    2012-01-01

    We investigated central Mediterranean Pinus halepensis plantations under semi-arid climate in order to evaluate the combined effect of soil treatment and afforestation practices on spontaneous plant species composition,richness and evenness,and on the trend and speed of vegetation dynamics.Phytosociological relevés of three different plot typologies,i.e.(1) soil-treatment and plantation,(2) only soil-treatment,(3) no soil-treatment and no plantation,were compared by (a) multivariate analysis and (b) with reference to species richness and evenness.Moreover,in order to compare vegetation dynamics within the plantations with those ones ongoing in semi-natural garrigue communities,we compared life form and syntaxonomic spectra between phytosociological relevés taken at 8 years of distance.DCA showed that floristic species composition and similarity are influenced by the canopy cover of Pine trees as well as by soil-treatment practices.Although species richness and evenness are not clearly related to neither soil treatment nor Pine afforestation,canopy cover clearly plays a major role:in fact,the highest Ph cover rates correspond to the lowest values of understory species richness.This is true also if only species of biogeographical/conservation interest are considered.Regarding vegetation dynamics,sites with dense Pine canopy cover evolve much slower than the adjacent garrigue communities.The same factors invoqued to explain the patterns of floristic composition and similarity (i.e.allelopathy and competition for light,water and nutrients) may also explain the lowering of diversity of therophytes and the strong decline of the cover perfomed by both therophytes and hemicryptophytes underneath the canopy of dense Ph plantations.Thus,in sites where Ph cover exceeds about 80%,thinning is recommended not only in order to accelerate succession,but also to give a natural 'shape' to afforestations.

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

    Science.gov (United States)

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

    2016-08-01

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

  17. Changes in gametophyte physiology of Pteris multifida induced by the leaf leachate treatment of the invasive Bidens pilosa.

    Science.gov (United States)

    Zhang, Kai-Mei; Shen, Yu; Fang, Yan-Ming; Liu, Ying

    2016-02-01

    In recent years, the response of fern gametophytes to environment has raised much attention. However, studies on the influence of plant invasion to fern gametophytes are scarce. Allelopathy plays an important role in biological invasion. Hence, it is necessary to study the allelopathic effects of invasive plants on fern gametophytes 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 spermatophyte growth. Field investigation shows that many ferns are threatened by the invasion of B. pilosa. The distribution of Pteris multifida overlaps with that of B. pilosa in China. To examine the potential involvement of allelopathic mechanisms of B. pilosa leaves, changes in the physiology in P. multifida gametophytes are analyzed. We found that cell membrane and antioxidant enzyme activities as well as photosynthesis pigment contents of the gametophytes were affected by B. pilosa leachates. Gametophytes of P. multifida exposed to B. pilosa had increased damages to cell membranes, expressed in thiobarbituric acid reacting substance (TBARS) concentrations, malondialdehyde (MDA), electrolyte leakage (membrane permeability), and degree of injury. Enzyme activities, assessed by superoxide dismutase (SOD) and catalase (CAT) as well as guaiacol peroxidase (GPX) enhanced with the increase in leachate concentration after 2-day exposure. Meanwhile, lower chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoid (Car), and the total chlorophyll were measured as leachate concentrations increased. At day 10, leaf leachates of B. pilosa exhibited the greatest inhibition. These results suggest that the observed inhibitory or stimulatory effects on the physiology studied can have an adverse effect on P. multifida and that allelopathic interference seems to have involved in this process.

  18. 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

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

    Science.gov (United States)

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

    2014-08-01

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

  20. Decline of Pseudodiaptomus hessei (Copepoda, Calanoida) in two water bodies located in the Senegal River hydrosystem (West Africa): Hypotheses and perspectives

    Science.gov (United States)

    Mendoza-Vera, Juana Mireya; Kâ, Samba; Cuoc, Corinne; Bouvy, Marc; Pagano, Marc

    2008-09-01

    Pseudodiaptomus hessei is a key species in many water bodies in the Senegal River hydrosystem but it became rare or completely disappeared from two ecosystems (Lake Guiers and Dakar Bango Reservoir; Senegal, West Africa) after major hydrological changes caused by human action, mainly impoundments on the river in 1985, and the opening of a new estuary mouth in 2003. Kâ et al. [Kâ, S., Pagano, M., Ba, N., Bouvy, M., Leboulanger, C., Arfi, R., Thiaw, O.T., Ndour, E.H.M., Corbin, D., Defaye, D., Cuoc, C., Kouassi, E., 2006. Zooplankton distribution related to environmental factors and phytoplankton in a shallow tropical lake (Lake Guiers, Senegal, West Africa). International Review of Hydrobiology 91(5), 389-405] put forward several hypotheses to explain the reasons for this decline: salinity and chemical changes in the water, predation by a cyclopid predator Mesocyclops ogunnus and/or the inhibiting effects of cyanobacteria and/or diatoms (allelopathy). This study assessed these hypotheses by studying the distribution of P. hessei in 13 stations (including the Dakar Bango reservoir and Lake Guiers) in relation to physical, chemical and biological (phyto- and zooplanktons) factors at each station. We produced a distribution pattern for this species in the Senegal River hydrosystem. Rank correlations and principal component analysis showed that P. hessei was not correlated with conductivity but was positively correlated with pH and alkalinity, suggesting chemical effects. The clear association with two filamentous cyanobacteria ( Cylindrospermopsis raciborskii and Anabaena sp.) did not appear to support the hypothesis of cyanobacteria inhibition but blooming conditions were never encountered during the study. Negative correlation with diatoms (especially with Fragilaria sp.) suggested that aldehyde producing diatoms had a negative effect. Negative correlations with cyclopids such as Mesocyclops supported the hypothesis of cyclopid predation to explain the decline of P

  1. Arbuscular mycorrhizal fungi facilitate the invasion of Solidago canadensis L. in southeastern China

    Science.gov (United States)

    Yang, Ruyi; Zhou, Gang; Zan, Shuting; Guo, Fuyu; Su, Nannan; Li, Jing

    2014-11-01

    The significance of arbuscular mycorrhizal fungi (AMF) in the process of plant invasion is still poorly understood. We hypothesize that invasive plants would change local AMF community structure in a way that would benefit themselves but confer less advantages to native plants, thus influencing the extent of plant interactions. An AMF spore community composed of five morphospecies of Glomus with equal density (initial AMF spore community, I-AMF) was constructed to test this hypothesis. The results showed that the invasive species, Solidago canadensis, significantly increased the relative abundance of G. geosperum and G. etunicatum (altered AMF spore community, A-AMF) compared to G. mosseae, which was a dominant morphospecies in the monoculture of native Kummerowia striata. The shift in AMF spore community composition driven by S. canadensis generated functional variation between I-AMF and A-AMF communities. For example, I-AMF increased biomass and nutrient uptake of K. striata in both monocultures and mixtures of K. striata and S. canadensis compared to A-AMF. In contrast, A-AMF significantly enhanced root nitrogen (N) acquisition of S. canadensis grown in mixture. Moreover, mycorrhizal-mediated 15N uptake provided direct evidence that I-AMF and A-AMF differed in their affinities with native and invading species. The non-significant effect of A-AMF on K. striata did not result from allelopathy as root exudates of S. canadensis exhibited positive effects on seed germination and biomass of K. striata under naturally occurring concentrations. When considered together, we found that A-AMF facilitated the invasion of S. canadensis through decreasing competitiveness of the native plant K. striata. The results supported our hypothesis and can be used to improve our understanding of an ecosystem-based perspective towards exotic plant invasion.

  2. Oxidation of phenolic acids by soil iron and manganese oxides

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, R.G.; Cheng, H.H.; Harsh, J.B.

    Phenolic acids are intermediary metabolites of many aromatic chemicals and may be involved in humus formation, allelopathy, and nutrient availability. Depending on their structures, six phenolic acids were shown to react at different rates with oxidized forms of Fe and Mn in a Palouse soil (fine-silty, mixed, mesic Pachic Ultic Haploxeroll). Increasing methoxy substitution on the aromatic ring of phenolic acids increased the reaction rate. Reaction rate was also increased for longer carboxyl-containing side chains. After 4 h reaction, little of the applied (10 mg kg/sup -1/ soil) p-hydroxybenzoic or p-coumaric acids had reacted, while 0 to 5, 70, 90, and 100% of the vanillic, ferulic, syringic, and sinapic acids, respectively, had reacted. After 72 h under conditions limiting microbial growth, none of the p-hydroxybenzoic, 30% of the p-coumaric, and 50% of the vanillic acids had reacted. The reaction was shown to be predominantly chemical, and not biological, since phenolic acid extractabilities were similar for Palouse soil and for Palouse soil pretreated with LiOBr to remove organic matter. When the Palouse soil was pretreated with a sodium dithionite-citrate solution to remove Fe and Mn oxides, none of the phenolic acids reacted after 1 h. The reaction of sinapic acid with Palouse soil was shown to produce Fe(II) and soluble Mn as reaction products. The reaction of phenolic acids with soil was thus shown to be an oxidation of the phenolic acids, coupled with a reduction of soil Fe and Mn oxides.

  3. Allelopathic assessment of selected common weeds in Malaysia

    Science.gov (United States)

    Nurul Ain, M. B.; Nornasuha, Y.; Ismail, B. S.

    2016-11-01

    A laboratory study was conducted to evaluate the allelopathic potential of eight common weed species in Malaysia, namely, Ageratum conyzoides, Tridax procumbens, Cyperus iria, Fimbristylis miliacea, Eleusine indica, Imperata cylindrica, Lygodium flexuosum and Nephrolepis biserrata of different morphological characteristics (broadleaves, sedges, grasses and ferns). The allelopathic study of these weeds was carried out by testing the leaf litter leachate through the Sandwich method and the volatile compounds of these weeds through the Dish pack method with three replicates for each donor species. The results obtained from both methods were statistically analyzed and the means had converted to percentage growth inhibition to determine the inhibition pattern on the radicle and hypocotyl growth of lettuce seedlings. Among the eight weed species tested, Ageratum conyzoides showed the strongest growth inhibition on lettuce radicle elongation (86%) in the sandwich bioassay compared to the control, followed by Tridax procumbens (71%), which both species being broadleaves weeds. In the dish pack bioassay Lygodium flexuosum (fern) demonstrated maximum inhibition on the growth the radicle and hypocotyl for each different distance from the source well. On the other hand, two weed species exhibited enhanced on the growth radicle and hypocotyl when compared to that of the control in dish pack bioassay. Nephrolepis biserrata and Fimbristylis miliacea were the species that showed the highest growth stimulatory effect. The results presented can be utilized as benchmark information for further research on the elucidation of leachates and volatile chemicals involved in allelopathy in nature. The information can also be helpful in the development of new bioactive chemicals from natural products in weed control strategies.

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

    Institute of Scientific and Technical Information of China (English)

    张秋菊; 张爱华; 孙晶波; 张连学

    2012-01-01

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

  5. 3个树种凋落叶水浸提液对三叶鬼针草生长及抗性生理的影响%Effect of Leaf Litter Water Extract of Three Species on Growth and Resistance Physiology of Bidens pilosa

    Institute of Scientific and Technical Information of China (English)

    廖梦雨; 胡庭兴; 邓承敏; 王茜; 龙华; 柏艺

    2014-01-01

    As an invasive plant, Bidens pilosa imposes great potential harm to agricultural production, biodiversity and safety of ecosystems. Making use of allelopathy to develop new herbicides, is a meaningful way to control and reduce nega⁃tive impact of chemical herbicides to the environment. It has been reported that leaf litters of common species, such as Eu⁃calyptus grandis, Cinnamomum camphora and Juglans regia, could generate secondary metabolites during their growing process, which show comparatively strong allelopathy to plants and microorganism, and might play an important role in the prevention of colonial invasion herbs. Selected leaf litters of E. grandis, C. camphora and J. regia, were made into differ⁃ent concentrations of water extracts. By combining the methods of indoor germination test and potted biological test, indexes such as germination rate, germination speed, aerial parts fresh weight, antioxidant enzyme activity, and osmotic regulation substance of B. pilosa were determined. Finally, comprehensive evaluation and comparison of allelopathy effects of the three species were completed. The water extracts of E. grandis leaf litter significantly inhibited the germination rate and germination speed of B. pilosa, while C. camphora and J. regia showed weaker inhibition. The leaf litter water extracts of the three tree species promoted the activity of peroxidase ( POD) , superoxide dismutase ( SOD) and inhibited the activ⁃ity of catalase ( CAT) in B. pilosa. The antioxidant enzyme system of B. pilosa treated with E. grandis leaf litter extract showed passivation response, and thus lead to obvious increase of malondialdehyde ( MDA) . When treated with leaf litter extracts of E. grandis and C. camphora, the soluble protein and soluble sugar in B. pilosa increased with increasing extract concentration. However, when treated by leaf litter extracts of J. regia, the soluble protein and soluble sugar in B. pilosa showed a trend of promotion at low

  6. 土荆芥挥发油对豌豆根边缘细胞的诱导和胁迫作用%Induced and stress effects of volatile oil from Chenopodium ambrosioide L. on root border cells of pea

    Institute of Scientific and Technical Information of China (English)

    何兵; 汪利沙; 王亚男; 张红; 李群; 马丹炜

    2013-01-01

      为探讨化感胁迫对根边缘细胞的诱导效应,实验采用悬空气培养法培养豌豆(Pisum sativum L.)露白种子,在保留根边缘细胞和去除根边缘细胞状态下,选取相对根长、根边缘细胞数量及死亡率、果胶甲基酯酶(PME)等指标研究了豌豆根边缘细胞对不同剂量土荆芥挥发油化感作用的响应。结果表明:1)与对照相比,随着挥发油处理剂量增加,根的伸长被显著抑制(P<0.05)。2)每个处理时间内,随着土荆芥挥发油剂量增加,根边缘细胞数量整体表现出先增加后减少的趋势,在低剂量2μL处理中达极大值。3)土荆芥挥发油诱导豌豆根边缘细胞死亡,随着处理时间的延长和处理剂量的增加,这种毒害效应程度加剧,除去边缘细胞实验组中10μL挥发油处理24 h时,根边缘细胞死亡率达到100%。在较低剂量挥发油作用下,保留根边缘细胞组的根边缘细胞死亡率高于去除根边缘细胞组,而在高剂量挥发油处理情况则相反。4)在同一处理时间,随挥发油剂量增加,各处理组PME活性持续升高,去处边缘细胞组处理24 h后不同剂量处理皆显著高于对照,而根边缘细胞数量总体表现先增加后减少。综合以上结果,保留根边缘细胞的根尖根边缘细胞的数量减少量较少,说明根边缘细胞能缓解土荆芥挥发油的化感胁迫;去除根边缘细胞组的PME活性升高较多,表明土荆芥化感胁迫诱导了根边缘细胞的产生。%The aim of this study was to investigate the inductive effect of root border cells (RBCs) of pea (Pisum sativum L.) under allelopathy related stress. Aeroponic method was used to cultivate the germinated pea seeds. Two types of samples were prepared, normal seed (control) and ones without root border cell (experimental group). Physiological indices, including relative root length, the number and mortality of RBCs, as well

  7. Effects of Watercress Extracts on Growth and Activities of Antioxidant Enzymes of Chlorella vulgaris%水芹水浸提液对小球藻生长及抗氧化酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    宰学明; 钦佩; 袁亚光; 吴向华; 周文宗

    2011-01-01

    [目的]研究水芹水浸提液对小球藻生长及其抗氧化酶活性的影响.[方法]采用小球藻在不同浓度的水芹水浸提液中纯培养的方法,测定小球藻生长速率、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性、·O2- 产生速率及丙二醛(MDA)含量的变化.[结果]10g/L水芹水浸提液处理下,SOD和POD活性逐步上升,至试验结束时都维持在较高的水平,·O2-产生速率和MDA含量与对照间无显著差异;20~50 g/L水芹水浸提液处理,藻细胞的SOD、POD活性、·O2-产生速率及MDA含量均呈先开高后降低的趋势,并且有浓度效应.[结论]水芹水浸提液对小球藻具有化惑效应.10 g/L水芹水浸提液对小球藻的生长具有明显的促进效应,20~50 g/L水芹水浸提液对小球藻有明显的克生作用.%[ Objective ] The effects of watercress extracts on the growth and activities of antioxidant enzymes of Chlorella vulgaris were studied.[ Method ] In pure culturing Chlorella vulgaris with different concentrations of watercress extract the growth, SOD and POD activity, · O2 -generating rate and MDA content of Chlorella vulgaris were determined. [ Result] Under the treatment of 10 g/L watercress extract the activity of SOD and POD increased gradually and maintained upper level in the whole process, · 02 - generating rate and the content of MDA didn' t have significant differences compared with control. Under the treatment of 20 - 50 g/L watercress extracts, the activity of SOD and POD, · O2 - generating rate and the content of MDA initially increased, then decreased, and intensified with time extension and concentration increase. [ Conclusion ] Watercress extracts had allelopathy on Chlorella vulgaris. On the whole,10 g/L watercress extracts promoted the growth of Chlorella vulgaris significantly, and 20 -50 g/L watercress extracts had obvious inhibition.

  8. Time-dependent alterations in growth, photosynthetic pigments and enzymatic defense systems of submerged Ceratophyllum demersum during exposure to the cyanobacterial neurotoxin anatoxin-a

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Mi-Hee; Pflugmacher, Stephan, E-mail: stephan.pflugmacher@tu-berlin.de

    2013-08-15

    Highlights: •We examined time-dependent metabolic changes in C. demersum exposed to anatoxin-a. •Biotransformation and antioxidative defense mechanisms responded positively to anatoxin-a. •Decline in chlorophylls contents was detected in company with irreversible plant growth inhibition during exposure to anatoxin-a. •Anatoxin-a exhibits phytotoxic allelopathy by provoking oxidative stress. •Macrophytes may have interactions with anatoxin-a in aquatic environments. -- Abstract: Recently, aquatic macrophytes have been considered as promising tools for eco-friendly water management with a low running cost. However, only little information is available thus far regarding the metabolic capacity of macrophytes for coping with cyanobacterial toxins (cyanotoxins) in the aquatic environment. Cyanotoxins have become emerging contaminants of great concern due to the high proliferation of cyanobacteria (cyanobacterial bloom) accelerated by eutrophication and climate change. Anatoxin-a, one of the common and major cyanotoxins, is suggested as a high priority water pollutant for regulatory consideration owing to its notoriously rapid mode of action as a neurotoxin. In this study, the time-course metabolic regulation of the submerged macrophyte Ceratophyllum demersum (C. demersum) was investigated during exposure to anatoxin-a at an environmentally relevant concentration (15 μg/L). Biotransformation and antioxidative systems in C. demersum responded positively to anatoxin-a through the promoted synthesis of most of the involved enzymes within 8 h. Maximum enzyme activities were exhibited after 24 or 48 h of exposure to anatoxin-a. However, an apparent decline in enzyme activities was also observed at longer exposure duration (168 and 336 h) in company with high steady-state levels of cell internal H{sub 2}O{sub 2}, which showed its highest level after 48 h. Meanwhile, irreversible inhibitory influence on chlorophyll content (vitality) was noticed, whereas the ratio of

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

    Directory of Open Access Journals (Sweden)

    Elizabeth Gorgone Barbosa

    2008-08-01

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

  10. 植物中SAMMtases基因研究进展%Progress of SAM Mtases Gene Study in Plants

    Institute of Scientific and Technical Information of China (English)

    穆红梅; 夏冰; 高俊平; 张秀省; 汪仁; 彭峰; 何树兰

    2012-01-01

    SAM Mtases是从多种植物中分离到的一类S-腺苷-L-甲硫氨酸依赖性氧位甲基转移酶基因,该基因对植物体内木质素、类苯基丙烷、类黄酮类、生物碱和脂肪族化合物等许多次生代谢产物合成有直接的影响,并且在植物抗病、抗紫外线、杀虫、抗菌、植物激素生长和信号调节、植物共生、花粉管伸长和花粉生长等生理过程中起重要作用.该文总结了国内外已经克隆到的SAM Mtases同源基因的分离、分类及其功能,为进一步研究SAM Mtases 基因在植物生理代谢调控中的地位及在植物抗性及药用成分育种上的应用提供参考.%SAMMtases was S-adenosyl-L-methionine dependent Omethyltransferase gene. The gene has a direct effect on plant lignin, class of phenyl propane, flavonoids, alkaloids and aliphatic compounds and many other secondary metabolite syntheses. It involved ir. plant disease resistance,UV resistance,insecticide, antiseptic, plant hormones,growth and signal conditioning,symbionts of plants,pollen tube elongation and pollen growth of plant allelopathy reaction. This review provides an overview on the research progress in separation,classification,and functions of SAM Mtases gene. It is helpful for better understanding of its position in plant physiological and metabolic regulation. We also highlight SAM Mtases gene as a candidate gene for plant resistance and plant secondary metabolism improvement.

  11. Effects of Solanum rostratum on seed germination and seedling growth of tomato%黄花刺茄浸提液对番茄种子萌发及幼苗生长的影响

    Institute of Scientific and Technical Information of China (English)

    平亚飞; 朱建雯; 张振国

    2012-01-01

    为明确入侵植物黄花刺茄对当地主栽经济作物番茄种子萌发和幼苗生长的影响,本文采用培养皿滤纸法,在智能光照培养箱的变温控制条件下,分别研究了黄花刺茄根、茎、叶浸提液对番茄种子发芽率、发芽指数及幼苗根长和苗高的影响.结果表明:(1)黄花刺茄不同器官的浸提液对番茄种子发芽率、发芽指数、幼苗根长和苗高的影响不同,其茎、叶浸提液的化感作用较为显著(P<0.01).(2)黄花刺茄同部位浸提液对番茄种子发芽率、发芽指数、幼苗根长和苗高不同指标的影响也不同.根漫提液对种子发芽率、幼苗根长影响不显著(P>0.05),但对种子发芽指数的影响极显著(P<0.01).茎和叶浸提液各浓度对种子发芽指数的影响比种子发芽率、幼苗根长和苗高的影响显著(P<0.01).%Solatium rostratum is a invasive weed, while tomato is a main local cultivated crop. We used the filter paper method in petri dish under variable temperature in illumination box to study the effects of the root, stem and leaf extract of Solarium rostratum on seed germination rate, germination speed, root length and seedling height of tomato. The results showed that: (1) The extract of different organs of Solarium rostratum had different effects on seed germination rate, germination speed, root length and seedling height of tomato, among which the allelopathy effects of the extract of stem and leaf were more significant ( P 0.05 ) for the seed germination rate and root length of tomato, but the effect was more significant on germination speed ( P < 0.01) . The effect of the extract of stem and leaf of Solarium rostratum on germination speed was the most significant ( P < 0.01) .

  12. 浒苔生物抗藻剂的研究和应用进展%On the Research and Application Progress of Bio-Algicide from Enteromorpha

    Institute of Scientific and Technical Information of China (English)

    刘海燕; 马栋; 单俊伟

    2016-01-01

    富营养化是指氮、磷等营养物质大量进入流动缓慢的水体,引起藻类及其他浮游生物大量繁殖和生长,使水中溶解氧含量迅速下降,最终导致鱼类和其他水生生物死亡。近年来,沿海赤潮频发,对海洋生态环境和水产养殖带来不利影响,如何有效地控制赤潮的发生已成为当前研究的热点之一。文章简要介绍水体富营养化的现状,包括引起水体富营养化的原因、富营养化防治措施,引出利用浒苔化感物质即浒苔生物抗藻剂进行生物防治赤潮的想法,治标治本,且不会对环境造成污染,为浒苔资源化利用及赤潮防治开辟新的方向。%Eutrophication is the phenomenon that large amount of nitrogen,phosphorus and other nutrient enter into the slowly flowing water,which causes algae and other plankton to propagate and grow,and makes the dissolved oxygen content in water drops rapidly,eventually leads to the death of fish and other aquatic organisms.In recent years,red tide has occurred frequently and have brought negative impact on marine environment and aquiculture.It has become one of hot spots of research on how to effectively control the red tide.This paper briefly introduced the sta-tus of eutrophication,including the causes,the prevention and control measures,and led to the use of enteromorpha allelopathy to control the red tide with a foundation solution,which is pollution-free for environment.It had opened up a new direction of enteromorpha resource utilization and the prevention and control of red tide.

  13. Molecular Identification of the Fungi in the Rhizospheric Soil of Soybean%大豆根际土壤真菌分子生物学鉴定方法

    Institute of Scientific and Technical Information of China (English)

    接伟光; 张勇; 蔡柏岩; 白莉; 王丽阳; 李二平

    2011-01-01

    The fungi in the rhizospheric soil of soybean played a vital role in the formation of soil fertility, the spread of soilborne diseases, the occurrence of allelopathy, etc. In particularly, soybean root rot caused by soil fungi has became a major disease which result in soybean production declined dramatically in China. Therefore, the rapid identification of the fungi in rhizospheric soil of soybean has great significance in preventing and curing fungal diseases of soybean. In this study, the fungal spores were isolated from soybean rhizospheres following a procedure including wet sieving, decanting, and separation in a sucrose gradient. Nested-PCR was conducted to specifically amplify the large-subunit (28S) rDNA D1/D2 domain sequences. They were identified from sequencing, and phylogenetic analysis. It showed that sequence alignment of the DT-1 28S rDNA D1/D2 domain sequence to fungi sequences in the database revealed that DT-1 shared 97% homology with the corresponding DT-1 sequence; DT-2 clusters shared 99% homology with the corresponding Mucor racemosus(Y213713) sequence. Results demonstrate that the method can get results quickly and accurately, and is suitable for identification of fungi in rhizospheric soil of soybean.%以大豆根际土壤为研究对象,采用湿筛倾析-蔗糖离心法分离大豆根际土壤真菌孢子.应用Nested-PCR技术扩增其28S rDNA D1/D2区域,并结合DNA测序、系统发育分析,对其进行分类鉴定.结果表明:筛选出的大豆根际土壤真菌孢子DT-1与土壤真菌(AB438763)有较高的序列同源性,为97%;DT-2与Mucor racemosus (Y213713)有较高的序列同源性,为99%.此方法适用于大豆根际土壤真菌的鉴定,并且能够快速准确地得到试验结果.

  14. De novo sequencing and analysis of the Ulva linza transcriptome to discover putative mechanisms associated with its successful colonization of coastal ecosystems

    Directory of Open Access Journals (Sweden)

    Zhang Xiaowen

    2012-10-01

    Full Text Available Abstract Background The green algal genus Ulva Linnaeus (Ulvaceae, Ulvales, Chlorophyta is well known for its wide distribution in marine, freshwater, and brackish environments throughout the world. The Ulva species are also highly tolerant of variations in salinity, temperature, and irradiance and are the main cause of green tides, which can have deleterious ecological effects. However, limited genomic information is currently available in this non-model and ecologically important species. Ulva linza is a species that inhabits bedrock in the mid to low intertidal zone, and it is a major contributor to biofouling. Here, we presented the global characterization of the U. linza transcriptome using the Roche GS FLX Titanium platform, with the aim of uncovering the genomic mechanisms underlying rapid and successful colonization of the coastal ecosystems. Results De novo assembly of 382,884 reads generated 13,426 contigs with an average length of 1,000 bases. Contiguous sequences were further assembled into 10,784 isotigs with an average length of 1,515 bases. A total of 304,101 reads were nominally identified by BLAST; 4,368 isotigs were functionally annotated with 13,550 GO terms, and 2,404 isotigs having enzyme commission (EC numbers were assigned to 262 KEGG pathways. When compared with four other full sequenced green algae, 3,457 unique isotigs were found in U. linza and 18 conserved in land plants. In addition, a specific photoprotective mechanism based on both LhcSR and PsbS proteins and a C4-like carbon-concentrating mechanism were found, which may help U. linza survive stress conditions. At least 19 transporters for essential inorganic nutrients (i.e., nitrogen, phosphorus, and sulphur were responsible for its ability to take up inorganic nutrients, and at least 25 eukaryotic cytochrome P450s, which is a higher number than that found in other algae, may be related to their strong allelopathy. Multi-origination of the stress related proteins

  15. Potencial alelopático de espécies nativas na germinação e crescimento inicial de Lactuca sativa L. (Asteraceae Allelopathic potential of native species in Lactuca sativa L. (Asteraceae germination and initial growth

    Directory of Open Access Journals (Sweden)

    Fabiana Maraschin-Silva

    2006-03-01

    Full Text Available A alelopatia caracteriza-se pelos efeitos danosos ou benéficos sobre o desenvolvimento da vegetação, causados por substâncias químicas produzidas e liberadas para o ambiente por uma planta. Com o objetivo de avaliar o potencial alelopático de espécies brasileiras, foram testados extratos foliares de Cecropia pachystachya Trec. (Urticaceae, Peltophorum dubium (Spreng. Taub. (Fabaceae, Psychotria leiocarpa Cham. & Schltdl (Rubiaceae, Sapium glandulatum (Vell. Pax (Euphorbiaceae e Sorocea bonplandii (Baill. Burg., Lanj. & Boer (Moraceae, utilizando-se bioensaios de germinação e crescimento e alface (Lactuca sativa L. como planta alvo. Nesses bioensaios, foram usados extratos foliares aquosos nas concentrações de 2 e 4%, preparados por maceração estática com água fria e quente. Os extratos das cinco espécies causaram atraso na germinação dos aquênios da alface, bem como efeitos tóxicos no crescimento das plântulas, com redução e enfraquecimento das raízes. Os resultados obtidos mostraram a presença de substâncias químicas inibidoras nos extratos, revelando potencial alelopático para as cinco espécies avaliadas.Allelopathy is characterized by harmful or beneficial effects on vegetation development, caused by chemical substances produced and released into the environment by the plant. Aiming to assess the allelopathic potential of Brazilian species, aqueous leaf extracts of Cecropia pachystachya Trec. (Urticaceae, Peltophorum dubium (Spreng. Taub. (Fabaceae, Psychotria leiocarpa Cham. & Schltdl (Rubiaceae, Sapium glandulatum (Vell. Pax (Euphorbiaceae, and Sorocea bonplandii (Baill. Burger, Lanj. & Boer (Moraceae were tested on lettuce using germination and growth bioassays. In these bioassays, aqueous leaf extracts were used at concentrations of 2 and 4%, prepared by static maceration with cold and hot water. The five species extracts delayed lettuce germination and produced toxic effects on seedling growth, with root

  16. Atividade alelopática de extrato de sementes de juazeiro Allelopatic activity of juazeiro seed extract

    Directory of Open Access Journals (Sweden)

    MFB Coelho

    2011-03-01

    Full Text Available Alelopatia é a liberação de substâncias vegetais inibidoras ou estimulantes no ambiente, podendo estar presente nas sementes de algumas espécies. O objetivo neste trabalho foi avaliar o potencial alelopático do extrato de sementes de juazeiro (Ziziphus joazeiro Mart. na germinação de sementes de alface (Lactuca sativa L. O experimento foi conduzido em delineamento inteiramente casualizado com quatro repetições e cinco tratamentos (0, 25, 50, 75 e 100% de concentração do extrato bruto. O extrato bruto foi obtido após a extração de 50 g de sementes e agitação em liquidificador com 500 mL de água. Os resultados mostraram efeito alelopático do extrato dependendo da concentração. As maiores concentrações do extrato de sementes de juazeiro afetaram a percentagem e velocidade de germinação e as menores proporcionaram plântulas anormais. Portanto, o extrato apresentou efeito alelopático desfavorável à germinação de sementes de alface.Allelopathy is the release of plant substances that inhibit or act as stimulants in the environment, and may be present in the seeds of some species. The objective of this work was to evaluate the allelopatic activity of the extract of juazeiro (Ziziphus joazeiro Mart. seeds on the germination of lettuce (Lactuca sativa L. seeds. We utilized the randomized design with four replications and five treatments (0, 25, 50, 75 and 100% of concentration of the crude extract. The crude extract was obtained after the extraction of 50 g of seeds, shaking them with 500 mL of water in a blender. The results showed allelopatic effect, proportional to the increase of the concentration of the extract. The highest concentrations of seed extract of juazeiro affected the percentage and speed of germination and the lowest concentrations caused abnormal seedlings on lettuce seed germination. Therefore, the extract presented an allelopatic effect, unfavorable to the germination of lettuce seeds.

  17. Biogenic volatile organic compounds - small is beautiful

    Science.gov (United States)

    Owen, S. M.; Asensio, D.; Li, Q.; Penuelas, J.

    2012-12-01

    While canopy and regional scale flux measurements of biogenic volatile organic compounds (bVOCs) are essential to obtain an integrated picture of total compound reaching the atmosphere, many fascinating and important emission details are waiting to be discovered at smaller scales, in different ecological and functional compartments. We concentrate on bVOCs below ground to allelopathy. A gradient of monoterpene concentration was found in soil around Pinus sylvestris and Pinus halepensis, decreasing with distance from the tree. Some compounds (α-pinene, sabinene, humulene and caryophyllene) in mineral soil were linearly correlated with the total amount of each compound in the overlying litter, indicating that litter might be the dominant source of these compounds. However, α-pinene did not fall within the correlation, indicating a source other than litter, probably root exudates. We also show that rhizosphere bVOCs can be a carbon source for soil microbes. In a horizontal gradient from Populus tremula trees, microbes closest to the tree trunk were better enzymatically equipped to metabolise labeled monoterpene substrate. Monoterpenes can also increase the degradation rate in soil of the persistant organic pollutants, likely acting as analogues for the cometabo-lism of polychlorinated biphenyls (PCBs) Flowers of a ginger species (Alpinia kwangsiensis) and a fig species (Ficus hispida) showed different bVOC signals pre- and post pollination. For Ficus hispida, there are three floral stages of a fig-wasp dependency mechanism: receptive, post pollinator and interfloral. Of 28 compounds detected, transcaryophyllene with trans-β-farnesene were the most important at the receptor stage, trans-caryophyllene was the most abundant at the post-pollinator stage, and isoprene was the most abundant in the interfloral stage. Alpinia kwangsiensis presents two morphologies for the reproductive parts of the flower. The "anaflexistyle" morphology has the flower style lowered in the

  18. Cover crop management in the weed control and productive performance in cornManejo de plantas de cobertura no controle de plantas daninhas e desempenho produtivo da cultura do milho

    Directory of Open Access Journals (Sweden)

    Pedro Valério Dutra de Moraes

    2013-05-01

    Full Text Available Objetivou-se avaliar espécies vegetais com potencial alelopático, associados às práticas de manejo e ao uso de herbicida nicosulfuron, no controle de plantas daninhas e nos componentes de produtividade da cultura do milho. O delineamento experimental utilizado foi em blocos ao acaso, com quatro repetições. O experimento foi composto por três fatores: espécies de cobertura, manejo das coberturas e aplicação ou não de herbicida nicosulfuron em pós-emergência. As variáveis avaliadas foram: número de plantas daninhas, número de fileiras de grãos, número de grãos por fileira, número de grãos por espiga e produtividade de grãos de milho. A cobertura de azevém, em geral, reduz o número de plantas daninhas emergidas e favorece o desempenho produtivo do milho. O manejo das plantas de cobertura com roçada e retirada da palha reduz a produtividade do milho. A maior produtividade do milho, foi observada com a aplicação de nicosulfuron em pós-emergência, independente da cultura de cobertura ou do manejo adotado. The objective of the study was evaluate the allelopathy of cover species, associated to management practices and use of nicosulfuron herbicide on the productive performance of corn. The experimental design consisted of complete randomized block with four replications. The treatments were: cover species, cover management and application or not of post-emergence herbicide. The variables evaluated were: number of weeds, number of rows kernels, number of kernels rows, number of kernels ear and grain yield of corn. Lolium multiflorum, reduced the number of emerged weeds and provides the best results in productive performance. The management simulated grazing, does not favor the yield of corn. The application of nicosulfuron in post-emergence, along with the allelopathic activity increases the productive performance of corn, regardless of cover crop or soil management.

  19. Miscanthus plants used as an alternative biofuel material. The basic studies on ecology and molecular evolution

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Chang-Hung [Graduate Institute of Ecology and Evolutionary Biology, College of Life Sciences, China Medical University, Taichung 404 (China)

    2009-08-15

    Miscanthus Anderss, widely distributed in Asia and Pacific Islands, possesses 20 species. Of which 8 species and 1 variety were recorded in Chinese Mainland; 6 species and 1 variety found in Japan; 5 species and 3 varieties distributed in Taiwan; 3 species documented in the Philippines; and rest of species have been recorded in Jawa, eastern Himalaya, and Sikkim. The plant is a C{sub 4} perennial grass with high productivity of biomass. In the 19th and early 20th centuries in Taiwan, Miscanthus was a very important crop used for forage grass, clothing, and shelter, etc. The relatively high germination, and high yield of biomass made the plant available for people of Taiwan including aboriginal. The taxonomic study of Miscanthus plants was much done by several scientists, and its ecological study has been only taken by the present author since 1972. Chou and his associates paid a great attention to elucidate the mechanism of dominance of Miscanthus vegetation and found that allelopathy plays an important role. In addition, the population biology of Miscanthus taxa by using polyacrylamide gel electrophoreses technique to examine the patterns of peroxidase and esterase among populations (over 100) of Miscanthus in Taiwan were conducted. They also elucidated the phylogenetic relationship among species and varieties in Taiwan. Chou and Ueng proposed an evolutionary trend of Miscanthus species, indicating that the Miscanthus sinensis was assumed to be the origin of Miscanthus Anderss, which evolved to M. sinensis var. formosana, and M. sinensis var. flavidus, and M. sinensis var. transmorrisonensis, and Miscanthus floridulus was thought to be an out group of M. sinensis complex. Moreover, molecular phylogeny was attempted to clarify the population heterogeneity of M. sinensis complex, resulting in a substantial information. It would be available for making hybridization between Miscanthus species and its related species, such as Saccharum (sugar cane) spp. which is a

  20. 旱地农业区危害大豆的鸟类及保护性预防%Birds Harm to Soybean in Dryland Agricultural Areas and Protective Prevention

    Institute of Scientific and Technical Information of China (English)

    降云峰; 刘学义

    2013-01-01

    With the improvement of living environment,the number of birds associated with soybean production in the northern China have been restored.As a member of the food chain,birds have close allelopathy relationship with soybean.Soybean seedlings are threatened by some birds of Columbidae and Phasianidae families in dry land area,which often results in soybean seedlings deficiency.These birds include rock pigeon,rock dove,gray turtledove,powder head turtledove,chukar,big chukar,pheasant and quail,most of them are national protected animals,hunting is strictly prohibited.Protective control measures based on the characteristics of these birds hazards soybean has proposed.Including(i) choose varieties with strong drought resistance,small grain,green cotyledon,and purple flower,so as to circumvent the hazard of birds;(ii) adopt cultivation techniques with fast centralized emergence targets to reduce bird hazards ; (iii) adopt bird repellents and apparatus measures to keep away the pest birds.%随着我国鸟类生存环境的改善,北方地区与大豆生产相关的鸟类数量得到恢复.鸟类与大豆具有十分密切的相生相克关系,是自然生态环境中食物链之一.旱地大豆苗期主要受鸠鸽科和雉科中部分鸟类威胁,常常导致大豆缺苗断垄或毁苗情况出现.这些鸟类包括岩鸽、原鸽、灰斑鸠、粉头斑鸠、石鸡、大石鸡、雉鸡和鹌鹑8个主要种类,它们多数为国家级保护动物,严禁猎杀.依据这些鸟类危害大豆的特点提出保护性防治措施,主要包括:(1)选择抗旱性强、籽粒小、子叶青色、紫花类型大豆品种,规避鸟类危害;(2)采用以快速集中出苗目标的栽培技术,减轻鸟类危害;(3)采用驱鸟剂和驱鸟器等保护性措施,防治鸟类危害.

  1. A new mechanism of invader success: Exotic plant inhibits natural vegetation restoration by changing soil microbe community

    Institute of Scientific and Technical Information of China (English)

    YU Xingjun; YU Dan; LU Zhijun; MA Keping

    2005-01-01

    Since the 1950s of the last century, the exotic plant, Eupatorium adenophorum, has spread rapidly across southwest China, damaging native ecosystems and causing great economic losses. We examined the pH, N, P, K, and organic matter concentrations, and the bacterial community character (by Biolog EcoPlateTM) in soils from sites heavily and lightly invaded by this exotic species. Also, soil from the lightly invaded site was treated with a water extract of E. adenophorum roots to examine the effect of the plant on soil properties. We grew three plant species, one native and two exotic, in pot experiment using soil from heavily invaded site to examine the effects of the soil on these plants growth. The soil analysis demonstrated that the pH, organic matter, total N, total P and total K in soils from the heavily invaded site were only slightly different from those of the lightly invaded site, but concentrations of NH4+, NO3? and available P and K in the heavily invaded site were greater than those in the lightly invaded site. The catabolic activity of soil bacterial community in the heavily invaded site was different from that in the lightly invaded site. The catabolic activity of bacterial community in soils treated by the water extract of E. adenophorum roots changed and became similar to that in soils from the heavily invaded site. The pot experiment showed that the exotic plants growth in heavily invaded soil were not different from in lightly invaded soil; however, the native plant biomass decreased dramatically when grown in soil from the heavily invaded site as compared to soil from the lightly invaded site; and the same phenomenon was found when any potential allelopathic effects by E. adenophorum were eliminated by added activated carbon to those soils. Difference in soil nutrient availability and allelopathy could not explain this phenomenon of the native plant in the soils from the heavily and lightly invaded sites. Changes observed in the soil bacterial

  2. Allelopathic effect of lemongrass and sabugueiro on Cuban jute germination/ Efeito alelopático de capim limão e sabugueiro sobre a germinação de guanxuma

    Directory of Open Access Journals (Sweden)

    Andréa Maria Teixeira Fortes

    2007-08-01

    Full Text Available The invasive species Cuban jute (Sida rhombifolia L. is common in no-till areas. It is an important competitor of crops because of a quite effective root system. For this reason, Cuban jute control commonly is made on large-scale applications of chemicals. This study seeks to make a contribution to the control of Cuban jute via allelopathy using hot aqueous extracts of the medicinal species lemongrass (Cymbopogon citratus Stapf. and sabugueiro (Sambucus australis Cham & Schltdl.. The experiment was carried out in two complementary steps: first we attempted to overcome dormancy of the invasive species, and then we investigated the effect of the medicinal species lemongrass and sabugueiro on Cuban jute germination. The seeds were placed in Petri dishes previously autoclaved for 20 minutes at 121°C and then taken to a germination chamber with a photoperiod of 12 hours at 25°C. A potential allelopathic, inhibitory effect was identified on Cuban jute seed germination when the weed was exposed to the hot aqueous extract of both medicinal species.A espécie invasora guanxuma (Sida rhombifolia L. é comum em áreas de plantio direto e destaca-se na competição com a cultura agrícola por apresentar um sistema radicular bastante eficiente; para tanto, seu controle depende comumente de aplicações químicas em larga escala. O presente estudo teve como objetivo avaliar o efeito alelopático do extrato aquoso quente das espécies medicinais capim limão (Cymbopogon citratus Stapf. e sabugueiro (Sambucus australis Cham & Schltdl. sobre a germinação da espécie invasora guanxuma. O experimento foi realizado em duas etapas complementares: primeiramente visou-se à quebra de dormência da espécie invasora e depois, verificou-se o efeito de capim limão e sabugueiro sobre a germinação de guanxuma. O acondicionamento das sementes foi realizado em placas de Petri previamente autoclavadas por 20 minutos a 121°C, dispostas em Câmara de Germinação com

  3. Response of Root Border Cells of Vicia faba L.to Volatile Oil from Erigeron canadensis L.%蚕豆根缘细胞对加拿大蓬挥发油的响应

    Institute of Scientific and Technical Information of China (English)

    张红; 贾贵芳; 王亚男; 李群; 马丹炜

    2011-01-01

    Allelopathy is one of the mechanisms by which an invasive alien species, Erigeron canadensis L.(horseweed) invades successfully and spreads rapidly.In order to further explore allelopathic and invasion mechanisms of this species, allelopathic effects ofvolatile oil from this species on root border cells and the activity of pectin methylesterase(PME) of broad bean were studied by aeroponic culture.The results showed that the volatile oil from E.canadensis inhibited the root growth, and the survival rate of root border cells decreased, and the activity of root pectin methylesterase increased.But the stimulating effect gradually lowered down along with the increasing doses of the volatile oil and treatment times.These results suggested that volatile oil from this species caused root border cells death and inhibited the growth of ambient plants.%化感作用是入侵植物加拿大蓬(Erigeron canadensis L.)成功入侵和快速扩散的机制之一.为了深入探讨加拿大蓬的化感机制和入侵枧制,以蚕豆为材料,采用悬空气法研究了加拿大蓬挥发油对根边缘细胞和果胶甲基酯酶的化感效应.结果表明在加拿大蓬挥发油作用下,蚕豆根的生长受到抑制,根缘细胞存活率下降,根果胶甲基酯酶活性升高,但随着挥发油剂量增大和作用时间延长,这种促进效应逐渐降低.这些结果说明加拿大蓬挥发油对根边缘细胞具有致死效应,从而抑制了周围植物的生长发育.

  4. 马铃薯对瓜列当种子萌发的化感作用研究%Allelopathic effect of potato on Orabanche aegyptiaca Pers.seed germination

    Institute of Scientific and Technical Information of China (English)

    王钟; 马永清; 贾锦楠; 董淑琦; 叶晓馨

    2013-01-01

    Orobanche aegyptiaca is a national-class quarantine species in China which is seriously harmful to melons and other economic crops.In this study, four commercial potato varieties ("Xiabodi", "Qingshu 168", "Jizhangshu No.5" and "Kexin No.1") were planted at a pot experiment, and their rhizosphere soils and plant organs (roots, stems and leaves) sampled at different growth stages (seedling, blossoming and tuber forming stages).Allelopathy potential of extracts (methanol and distilled water) of the above samples was measured in terms of germination rates of O.aegyptiaca seeds treated.The potatoes varieties with O.aegyptiaca seed high germination rates were chosen to prevent and kill off O.aegyptiaca seeds on croplands.The results showed that potato stimulated O.aegyptiaca germination, and the allelopathy potential differed with potato variety.The germination rates of O.aegyptiaca seeds treated with extracts of potato rhizosphere soil increased with potato growth.This suggested that potato secreted O.aegyptiaca germination stimulants at certain period of growth which in turn reduced O.aegyptiaca seed bank in the soil.At seedling stage of potato, the germination rate of O.aegyptiaca seeds treated with 10-fold diluted methanol extracts from potato roots was higher than those from the shoot system.Seeds treated with "Xiabodi" showed the highest germination rate (48.5%).At blossoming stage of potato, the germination rate of O.aegyptiaca seeds treated with 10-fold diluted methanol extracts from stems was highest, followed by those treated with root extracts and leaf extracts.Seeds treated with "Jizhangshu No.5" had the highest germination rate (33.0%).At tuber forming stage of potato, the germination rate of O.aegyptiaca seeds treated with 10-fold diluted methanol extracts from shoot system was higher than those from roots.Also seeds treated with "Xiabodi" gave the highest germination rate (51.2%).While the germination rate of O.aegyptiaca seeds treated with root extracts

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

    Institute of Scientific and Technical Information of China (English)

    孙海燕; 王炎

    2012-01-01

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

  6. Research Progress in the Volatile Organic Compounds of Plant%植物挥发性有机化合物研究方法进展

    Institute of Scientific and Technical Information of China (English)

    李军

    2016-01-01

    植物产生的挥发性有机化合物在调节植物与周围环境间的信息交流中起着重要作用,是生态系统中重要的化学信号物质。植物挥发性有机化合物在植物间的化学通讯、植物化感作用,植食性昆虫的寄主选择及天敌对植食性昆虫的定位等生态过程中发挥着重要的作用,是植物和昆虫长期协同进化、互相适应的结果。文章主要介绍植物挥发性有机化合物的收集方法——固相微萃取法和固体吸附法的原理、方法和应用注意事项等,比较了不同收集方法的优缺点。同时介绍了植物挥发性有机物化合物常用的气相色谱或气相色谱-质谱联用分析测定方法及植物挥发性有机化合物对昆虫和天敌行为的影响等,并在此基础上展望了今后植物挥发性有机化合物研究方法方向,为下一步开展植物挥发性有机化合物研究方法提供参考依据。%Volatile organic compounds (VOCs) released from plant play an important role in mediating plants to communicate and interact with the environment. VOCs are one of the important chemical signals in the ecosystem. VOCs acting as signal chemicals also played an important role in plant communication, plant allelopathy, host selection of phytophagous insects, host orientation of natural enemies and so on. VOCs are consequences of long-term plant-insect interactions and coevolution. In this paper, we introduced and analyzed the two techniques for the collection of VOCs, the solid-phase microextraction (SPME) method and the absorbent method. We compared the principles, procedures, key points and examples of the two collection methods and pointed out their advantages and disadvantages. At the same time, we introduced analysis method of gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) for analysis the chemical compounds of VOCs. At last, research methods related to analysis and determination the influence of

  7. 空心莲子草水浸提液对水稻根缘细胞的化感作用%Allelopathic Effect of Aqueous Extracts of Alternanthera philoxeroides on Root Border Cells of Oryza sativa

    Institute of Scientific and Technical Information of China (English)

    王桂芹; 郑玉华; 张晓娟

    2012-01-01

    increases, and then inhibites, but that from stems was contrary to the effect of leaves, roots and rhizome. Synthesis effect of water - solubility allelopathie substance from differences vegetative organs of A. philoxeroides are arranged as follows: leaves 〉 root and rhizome 〉 stem.

  8. Chemical Composition and Allelopathyc Activity of Essential Oil of Lippia sidoides Cham Composición química y actividad alelopática del aceite esencial de Lippia sidoides Cham

    Directory of Open Access Journals (Sweden)

    Cláudia Araújo Marco

    2012-03-01

    Full Text Available The allelopathy is a process for which products of the secondary metabolism, as terpenes phenolic, of a certain vegetal intervene significantly, generally of antagonistic form, in the development of other species of plants. The objective of this work was to chemically characterize the essential oil of Lippia sidoides Cham. growing in the Cariri cearense region, Brazil, and evaluate the allelopathyc effect of this oil on the germination of lettuce (Lactuca sativa L., arugula (Eruca sativa Mill., and cauliflower (Brassica oleracea L., in pre-plantation application. The monoterpene thymol (84.90% has been identified as the principal constituent in the essential oil. The experiment was done in randomized complete block, in 4 x 3 factorial; being used four essential oil combinations applied in three different species in pre-plantation applications. Emergence velocity index (EVI, germination percentage and mean time to germination (MTG, had been analyzed through daily counting carried out until the 14th day after sowing. Through qualitative analysis performed by gas chromatography coupled with mass spectrometry (GC/MS were identified seven chemical constituents representing 97.82% of essential oil of L. sidoides, being that the constituent present in greater concentration in oil was the thymol (84.90%. Could be verified the occurrence of the negative allelopathyc effect of lettuce crop, because its present low EVI and greater MTG, for the other vegetable species there were no allelopathic effect.La alelopatía es un proceso mediante el cual productos metabólicos secundarios, tales como terpenos fenoles, producidos por una planta en particular interfieren significativamente, y de manera antagónica, en el desarrollo de otras especies vegetales. Nuestros objetivos fueron caracterizar químicamente el aceite esencial de Lippia sidoides Cham., cultivada en la región de Cariri Ceará, y evaluar el efecto alelopático del aceite aplicado en pre-siembra en

  9. 杂草抗药性及其治理策略研究进展%Research Progress on Weed Resistance to Herbicides and Control Methods

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The mechanisms and factors that influence the evolution of herbicide resistance in weeds are reviewed along with the weed control practices available for the control of herbicide -resistant weeds.Weed resistance to herbicides can be of two types,namely target -site resistance that includes the alteration of the site of action,gene amplification and over-expression,and non -target -site resistance that includes enhancement of metabolic detoxification,limited uptake and translocation,and compartmentalization.The evolution of weed resistance is influenced by many factors,such as resistance mutation frequency,herbicide selective pressure,weed fitness and weed seed bank life.Additionally,gene mutation and genetic characteristics are directly related to its evolution.It is advisable to investigate and identify resistant weeds in fields regularly,apply herbicides properly (with rotation or mixture of active ingredients),and to integrate agronomic man-agement practices to prevent evolution of weed resistance to herbicides in the future.Additionally,fundamental research on allelopathy in plants should be emphasized for providing theoretical bases for developing safer herbicides.%综述了杂草抗药性产生机理、杂草抗药性演化影响因素,并对其治理途径进行阐述,为杂草抗药性治理提供参考。除草剂抗药机制分为靶标抗性、非靶标抗性,其中靶标抗性包括除草剂作用位点改变、基因倍增及过量表达;非靶标抗性主要包括代谢解毒能力增强、屏蔽作用或与作用位点的隔离作用等。杂草抗药性演化受多种因素共同影响,不仅包括抗药性突变频率、除草剂选择压、杂草适合度及杂草种子库寿命四大因素,还与基因突变和遗传特征直接相关。在未来的杂草治理中,要经常进行田间杂草调查与鉴定,正确使用除草剂(交替使用、混用),并辅以合理的农艺管理措施来减缓杂草抗药性的演化速

  10. 红小豆根系水浸提液对4种受体作物的化感作用%Allelopathic Effect of Adzuki Bean Root Aqueous Extracts on Four Crops

    Institute of Scientific and Technical Information of China (English)

    连慧达; 裴红宾; 张永清; 秦成

    2014-01-01

    For choosing suitable summer-planting adzuki bean crop, this experiment adopted the method of indoor petri dish bioassay to study the allelopathy effect of adzuki bean, radish, cabbage and wheat under different concentrations of adzuki bean root aqueous extracts. The result showed that the adzuki bean had a strong inhibition towards its germination rate and germination index. With the increasing of adzuki bean root aqueous extracts concentration, the seed germination rate and germination index of the three kinds of receptor crops presented a decreasing trend. From the root length, young leaves length, the number of lateral roots, plant height, fresh weight and other forms indicators of seedlings, it was concluded that with the increase of adzuki bean root aqueous extracts concentration, only wheat presented a promoting effect while the other two kinds of receptor crops show inhibitory effect, which were not significant at low concentrations. With the increase of adzuki bean root extracts concentration, the SOD and POD activity of radish and wheat also increased, but the two kinds of enzyme activity of cabbage showed a decreasing trend. The MDA content in seedlings of radish and wheat decreased, but the MDA content in cabbage increased significantly, which showed that receptor crop wheat could be used as rotation crop of adzuki bean, radish also had a great application potential in adzuki bean crop rotation.%为选择适合红小豆的接茬作物,采用室内培养皿生物测定方法,对不同浓度的红小豆根系水提液下红小豆、萝卜、白菜、小麦的化感效应进行了研究。结果表明:红小豆水提液对自身种子发芽率、发芽指数具有极强的化感抑制作用;随着红小豆根系水提液浓度的增大,3种受体作物的种子发芽率和发芽指数均呈现降低趋势;从幼苗的根长、幼叶长、侧根数、株高及鲜质量等形态指标上来看,只有小麦随着红小豆根系水提液浓度

  11. Effects of forest litter layer on regeneration of Populus cathayana natural population in Xiaowutai Mountains in China%小五台山森林落叶层对天然青杨种群更新方式的影响

    Institute of Scientific and Technical Information of China (English)

    李霄峰; 胥晓; 王碧霞; 黄尤优; 王志峰; 李俊钰

    2012-01-01

    通过野外样方调查和室内种子萌发实验两种方法,对河北小五台山天然青杨(Populus cathayana)种群的更新方式进行了研究,以揭示落叶层的化感作用和机械阻挡作用对青杨种子萌发的干扰机理.结果显示:1)种群样方中的幼苗都为无性繁殖的克隆分株,种子繁殖的幼苗年自然存活率为0%;2)落叶层对种子幼苗的存活率有显著影响.50 mg·mL-1浓度的落叶水浸液可使青杨种子发芽率降低41%,使主根长度减少95%,100 mg·mL-1浓度的落叶水浸液则完全抑制种子萌发;单层和多层落叶对种子萌发产生的影响差异不显著,都能完全阻碍种子的根系正常生长,导致幼苗脱水干枯死亡.结果表明,在高海拔山区的青杨天然林中,由于不断积累的落叶层通过化感作用和机械阻挡作用严重影响种子的萌发、定根以及上正常生长,从而导致种子更新的途径受阻,而只能通过无性繁殖来完成正常的种群更新.%Aims Populus cathayana, a typical riparian tree in northern China, can produce substantial seeds and numerous clones. Several studies in the last few years indicated that the proportion of seedlings and clones in the population was correlated with factors such as river flooding, soil substrates and slope gradient. Our objective was to investigate the regeneration mode of Populus cathayana located in high-elevation woodland of Xiaowutai Mountains, revealing why there was such a phenomenon.Methods From 2010 to 2011, we excavated 1 284 small P. Cathayana saplings along an elevational gradient in high-elevation woodland of Xiaowutai Mountains to determine their method of origin. The influence of allelopathy and mechanical effects of litter layer on seedling regeneration was investigated by a series of controlled experiments.Important findings Regeneration was overwhelmingly from clonal propagation. Litter layer had a negative effect on recruitment from seed. Under treatment of

  12. 模拟酸雨对紫茎泽兰种子萌发和幼苗生长及化感作用的影响%Effects of simulated acid rain on seed germination,seedling growth and allelopathic potential of Eupatorium adenophorum

    Institute of Scientific and Technical Information of China (English)

    朱繤之; 刘莎; 阳从魏; 唐凯; 高婷

    2016-01-01

    酸雨作为全球环境问题中的一个重要议题,但与生物入侵的关系常常被人们忽视.文中利用外来入侵植物紫茎泽兰(Eupatorium adenophorum)作为研究对象,研究模拟酸雨(pH分别为2.5、4.0和5.6,并且H2 SO4与HNO3摩尔浓度比为5.17∶1的混合酸溶液)对其种子萌发和幼苗生长的影响.同时将酸雨污染与生物入侵通过化感作用联系起来,用模拟酸雨浸提紫茎泽兰叶片化感物质,考察其对受体植物旱稻(Oryza sativa L.)、黑麦草(Lolium perenne)、紫花苜蓿(Medicago sativa)和小麦(Triticum aestivum L.)种子萌发和幼苗生长的影响.结果表明:酸雨存在时,紫茎泽兰种子萌发和幼苗生长受到明显抑制,尤其在pH 2.5的模拟酸雨下,紫茎泽兰已完全不能发芽.对于紫茎泽兰化感作用来说,当以旱稻和小麦为受体植物时,模拟酸雨并未增强紫茎泽兰浸提液的抑制作用;但当以黑麦草和紫花苜蓿为受体植物时,模拟酸雨显著增强了紫茎泽兰浸提液的化感作用效果.%As one of the most important issues of global environmental problems,acid rain may have a close rela-tionship with biological invasions.Here we used Eupatorium adenophorum,the most destructive alien plant spe-cies in China,to study the effects of simulated acid rain (mixed acid solution made of H2 SO4 and HNO3 , 5.17 ∶1 )on its germination and seedling growth.Since allelopathy serves as“bridge”in connection of acid rain pollution and biological invasion,we also used simulated acid rain to leach E.adenophorum leaves to study its impact on germination and seedling growth of four plant species,Oryza sativa L.,Lolium perenne,Medicago sati-va,and Triticum aestivum L.The results showed that the germination and seedling growth of E.adenophorum were significantly inhibited by simulated acid rain.Especially when pH 2.5 simulated acid rain applied,E.ade-nophorum could not

  13. Lake Granbury and Lake Whitney Assessment Initiative Final Scientific/Technical Report Summary

    Energy Technology Data Exchange (ETDEWEB)

    Harris, B. L. [Texas AgriLife Research, College Station, TX (United States); Roelke, Daniel [Texas AgriLife Research, College Station, TX (United States); Brooks, Bryan [Texas AgriLife Research, College Station, TX (United States); Grover, James [Texas AgriLife Research, College Station, TX (United States)

    2010-10-11

    blooms. Our numerical modeling results support the idea that cyanobacteria, through allelopathy, control the timing of golden algae blooms in Lake Granbury. The in-lake experiments in Lake Whitney and Lake Waco also revealed that as golden algae blooms develop, there are natural enemies (a species of rotifer, and a virus) that help slow the population growth. Again, better characterization of these organisms is a high priority as it may be key to managing golden algae blooms. Our laboratory and in-lake experiments and field monitoring have shown that nutrient additions will remove toxicity and prevent golden algae from blooming. In fact, other algae displace the golden algae after nutrient additions. Additions of ammonia are particularly effective, even at low doses (much lower than what is employed in fish hatchery ponds). Application of ammonia in limited areas of lakes, such as in coves, should be explored as a management option. The laboratory experiments and field monitoring also show that the potency of toxins produced by P. parvum is greatly reduced when water pH is lower, closer to neutral levels. Application of mild acid to limited areas of lakes (but not to a level where acidic conditions are created), such as in coves, should be explored as a management option. Finally, our field monitoring and mathematical modeling revealed that flushing/dilution at high enough levels could prevent P. parvum from forming blooms and/or terminate existing blooms. This technique could work using deeper waters within a lake to flush the surface waters of limited areas of the same lakes, such as in coves and should be explored as a management option. In this way, water releases from upstream reservoirs would not be necessary and there would be no addition of nutrients in the lake.

  14. 作物格局、土壤耕作和水肥管理对农田杂草发生的影响及其调控机制%Effects of crop pattern,tillage practice and water and fertilizer management on weeds and their control mechanisms

    Institute of Scientific and Technical Information of China (English)

    赵玉信; 杨惠敏

    2015-01-01

    Field weeds pose significant threats to agricultural production.Weed occurrence is affected by many factors,both natural and artificial.Crop pattern,tillage practices and the management of water and fertiliser are three fundamental factors.In this review paper,we summarize the effects of crop species and the temporal and spatial patterns of cropping.We describe the weed control outcomes of different planting modes,and com-pare changes in weed communities under different tillage practices and fertiliser applications.Possible control mechanisms are identified by considering the competition for resources between crops and weeds,crop allelopa-thy and changes in soil seed banks.Reasonable crop rotation,intercropping and mixed intercropping signifi-cantly restrain weed occurrence.No-tillage can increase weed community diversity.Straw mulch can reduce weed density and biomass.The effects of fertiliser application on weeds vary due to differences in crop species, fertiliser amount and type.Long-term balanced fertilisation can reduce weed density but increase weed commu-nity diversity.Irrigation and improved efficiency of natural precipitation use can inhibit upland weeds,and deep water management at appropriate times can effectively control some weeds in paddy fields.We conclude with some suggestions and prospects for future research on weed control.%农田杂草的危害是阻碍农业生产快速、健康发展的主要因素之一。农田杂草的发生受到诸多自然因素的影响和人工措施的调控,而作物格局、土壤耕作和水肥管理是除施用除草剂外最基本的人工干扰措施。本文综述了作物种类和时空格局对杂草的影响,阐述了主要的作物种植模式防治杂草的效果,并比较了不同土壤耕作和水肥管理措施下杂草群落的变化,重点剖析了杂草发生的调控机制,探讨了通过作物与杂草的资源竞争、作物的他感作用及土壤种子库的变化来调控杂草发生

  15. 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

  16. Allelopathic effect of aqueous extracts of Eucalyptus globulus Labill. and of Casearia sylvestris Sw. on cropsEfeito alelopático de extratos aquosos de Eucalyptus globulus Labill. e de Casearia sylvestris Sw. sobre espécies cultivadas

    Directory of Open Access Journals (Sweden)

    Grasielle Soares Gusman

    2011-10-01

    Full Text Available Allelopathy is characterized by the harmful or benefic effects caused by secondary metabolites, that are produced by plants, microorganisms or fungi and are released in the environment, on the development of natural biological systems or implemented ones. This study aimed to evaluate the allelopathic effects of aqueous extracts of eucalypt (Eucalyptus globulus Labill. and wild coffee (Casearia sylvestris Sw. on the germination and initial development of mustard (Brassica campestris L., cabbage (Brassica oleracea L. cv. capitata, broccoli (Brassica oleracea L. cv. italica, kale (Brassica pekinensis L., lettuce (Lactuca sativa L. cv. grand rapids, tomato (Lycopersicum esculentum Miller, turnip (Brassica rapa L., rucola (Eruca sativa L. and radish (Raphanus sativus L.. Six concentrations of each aqueous extract were tested (10, 30, 50, 70, 90 and 100% and compared to control (distilled water, with five replicates of each concentration, being ten seeds of each crop distributed in each replicate. The aqueous extracts of E. globulus and C. sylvestris reduced significantly the percentage of seed germination, the index of germination speed and the initial growth of the above ground part and roots of all cultivated species, being the reduction of these parameters higher with the increment of the aqueous extracts concentration, which led to thicker and atrophied roots with a higher number of absorbent hairs. Therefore, the results indicate an existence of allelopathic potential of E. globulus and C. sylvestris.A alelopatia caracteriza-se pelos efeitos danosos ou benéficos que metabólitos secundários produzidos por plantas, microrganismos ou fungos liberados no ambiente exercem sobre o desenvolvimento de sistemas biológicos naturais ou implantados. O objetivo do trabalho foi avaliar o efeito alelopático de extratos aquosos de eucalipto (Eucalyptus globulus Labill. e guaçatonga (Casearia sylvestris Sw. na germinação e no crescimento inicial de

  17. Atividade alelopática de extratos de diferentes orgãos de Caesalpinia ferrea na germinação de alface Allelopathic activity of extracts from different organs of Caesalpinia ferrea on lettuce germination

    Directory of Open Access Journals (Sweden)

    Andreya Kaliana de Oliveira

    2012-08-01

    Full Text Available A alelopatia pode afetar muitos aspectos da ecologia das plantas, incluindo a ocorrência, crescimento, sucessão de plantas, estrutura das comunidades, dominância, diversidade e produtividade. Neste trabalho, o objetivo foi avaliar o potencial alelopático de diversos órgãos de jucá (Caesalpinea ferrea sobre a germinação de sementes e desenvolvimento de plântulas de alface (Lactuca sativa. Foi usado o delineamento experimental inteiramente casualizado no esquema fatorial 2x5, com dois métodos de extração (25 e 100°C e cinco concentrações do extrato bruto (0, 25, 50, 75 e 100% para cada órgão avaliado: folhas, cascas e vagens maduras de C. ferrea, em quatro repetições de 25 sementes da alface 'Mônica SF FI'. As características avaliadas foram porcentagem de germinação (PG, índice de velocidade de germinação (IVG, porcentagem de plântulas normais (PN e anormais (PA, comprimentos da parte aérea (CPA e da raiz (CR de plântulas de alface. Os extratos de folhas e de vagens de C. ferrea obtidos a quente (100°C reduziram a porcentagem de germinação de L. sativa em relação à testemunha (0%. Nas maiores concentrações dos extratos de todos os órgãos, houve alta PA (atrofiamento da raiz, queima e escurecimento da radícula, encurvamento do caulículo, geotropismo negativo e menor CPA e CR, comparado à testemunha. Os extratos dos diferentes órgãos de C. ferrea apresentam atividade alelopática inibindo o desenvolvimento de plântulas de alface.Allelopathy can affect many aspects of plant ecology, including the occurrence, growth, plant succession, community structure, dominance, diversity and productivity of plants. The aim of this study was to evaluate the allelopathic potential of various organs of jucá (Caesalpinea ferrea on seed germination and seedling development of lettuce (Lactuca sativa. It was used in a completely randomized 2x5 factorial arrangement, with two extraction methods (25 and 100°C and

  18. Monte Carlo method based radiative transfer simulation of stochastic open forest generated by circle packing application

    Science.gov (United States)

    Jin, Shengye; Tamura, Masayuki

    2013-10-01

    Monte Carlo Ray Tracing (MCRT) method is a versatile application for simulating radiative transfer regime of the Solar - Atmosphere - Landscape system. Moreover, it can be used to compute the radiation distribution over a complex landscape configuration, as an example like a forest area. Due to its robustness to the complexity of the 3-D scene altering, MCRT method is also employed for simulating canopy radiative transfer regime as the validation source of other radiative transfer models. In MCRT modeling within vegetation, one basic step is the canopy scene set up. 3-D scanning application was used for representing canopy structure as accurately as possible, but it is time consuming. Botanical growth function can be used to model the single tree growth, but cannot be used to express the impaction among trees. L-System is also a functional controlled tree growth simulation model, but it costs large computing memory. Additionally, it only models the current tree patterns rather than tree growth during we simulate the radiative transfer regime. Therefore, it is much more constructive to use regular solid pattern like ellipsoidal, cone, cylinder etc. to indicate single canopy. Considering the allelopathy phenomenon in some open forest optical images, each tree in its own `domain' repels other trees. According to this assumption a stochastic circle packing algorithm is developed to generate the 3-D canopy scene in this study. The canopy coverage (%) and the tree amount (N) of the 3-D scene are declared at first, similar to the random open forest image. Accordingly, we randomly generate each canopy radius (rc). Then we set the circle central coordinate on XY-plane as well as to keep circles separate from each other by the circle packing algorithm. To model the individual tree, we employ the Ishikawa's tree growth regressive model to set the tree parameters including DBH (dt), tree height (H). However, the relationship between canopy height (Hc) and trunk height (Ht) is

  19. Potential phytotoxic and shading effects of invasive Fallopia (Polygonaceae taxa on the germination of native dominant species

    Directory of Open Access Journals (Sweden)

    Lenka Moravcová

    2011-08-01

    riparian-like habitats where it often encounters U. dioica populations, while F. ×bohemica tends to occur more often in ruderal sites with a high representation of C. epigejos; this might imply that each of the knotweed species exhibits a stronger effect on native species that are dominant in habitats they typically invade. The weakest phytotoxic effect of F. japonica corresponds to the results of previous studies that found this species to be generally a weaker competitor than its two congeners. Although the results of our experiments cannot be taken as a direct evidence for allelopathic effects acting in the field, the demonstrated potential phytotoxic effect of invasive Fallopia species on the germination of native species suggests that allelopathy may play a role in the strong impact of knotweed invasion on species diversity of invaded communities observed in the field.

  20. Soil microbial activities beneath Stipa tenacissima L. and in surrounding bare soil

    Science.gov (United States)

    Novosadová, I.; Ruiz Sinoga, J. D.; Záhora, J.; Fišerová, H.

    2010-05-01

    Open steppes dominated by Stipa tenacissima L. constitute one of the most representative ecosystems of the semi-arid zones of Eastern Mediterranean Basin (Iberian Peninsula, North of Africa). These steppes show a higher degree of variability in composition and structure. Ecosystem functioning is strongly related to the spatial pattern of grass tussocks. Soils beneath S. tenacissima grass show higher fertility and improved microclimatic conditions, favouring the formation of "resource islands" (Maestre et al., 2007). On the other hand in "resource islands" and in surrounding bare soil exists the belowground zone of influence. The competition for water and resources between plants and microorganisms is strong and mediated trough an enormous variety of exudates and resource depletion intended to regulate soil microbial communities in the rhizosphere, control herbivory, encourage beneficial symbioses, and change chemical and physical properties in soil (Pugnaire et Armas, 2008). Secondary compounds and allelopathy restrict other species growth and contribute to patchy plant distribution. Active root segregation affects not only neighbourś growth but also soil microbial activities. The objective of this study was to assess the effect of Stipa tenacissima on the key soil microbial activities under controlled incubation conditions (basal and potential respiration; net nitrogen mineralization). The experimental plots were located in the province Almería in Sierra de los Filabres Mountains near the village Gérgal (southeast Spain) in the small catchment which is situated between 1090 - 1165 m a.s.l. The area with extent of 82 000 m2 is affected by soil degradation. The climate is semiarid Mediterranean. The mean annual rainfall is of about 240 mm mostly concentrated in autumn and spring. The mean annual temperature is 13.9° C. The studied soil has a loam to sandy clay texture and is classified as Lithosol (FAO-ISRIC and ISSS, 1998). The vegetation of these areas is an

  1. Estudo fitoquímico e alelopático do extrato de caule de sucupira-branca (Pterodon emarginatus Phytochemistry and allelophatic study of Pterodon emarginatus stem extract

    Directory of Open Access Journals (Sweden)

    M.G. Hernández-Terrones

    2007-12-01

    Full Text Available A alelopatia é um dos fenômenos pouco estudados no Cerrado. Trata-se de uma ocorrência natural, resultante da liberação de substâncias capazes de estimular ou inibir o desenvolvimento de outras plantas. Objetivou-se neste trabalho avaliar a ação alelopática de extratos da sucupira-branca (Pterodon emarginatus sobre a germinação e o desenvolvimento da raiz e parte aérea do capim-colonião (Panicum maximum. Bioensaios de germinação realizados em placas de Petri comprovaram que o extrato metanólico do tronco dessa planta, a 150 ppm, inibiu 83% do desenvolvimento da raiz, 75% da parte aérea e 30% da germinação de sementes de capim-colonião. Em casa de vegetação, os resultados de inibição foram de 83% para a parte aérea, 80% para a raiz e 63% para a germinação, mas somente na concentração de 400 ppm. Frações do extrato metanólico bruto obtidas por cromatografia de coluna cromatográfica não reproduziram os resultados de inibição obtidos inicialmente. A fração mais ativa (diclorometano/clorofórmio foi analisada por CG/EM. Ela é constituída fundamentalmente por substâncias alifáticas de cadeia longa: fitol (13,5%, ácido oléico (12,8%, linoleiladato de metila (10,9% e ácido palmítico (6,9%. Foram detectados, também, os compostos 1,2,4-trimetil e isopropilbenzenos (12,2% e as cetonas isoméricas isopropenilmetilcetona e 3-penten-2-ona (7,3%. Três compostos desconhecidos também se destacaram: um de baixa massa molar (98 Da, 13,5% e dois de massa molar elevada (13,6%.Allelopathy is one of the natural phenomena little studied in the cerrado. It is the result of the release of substances capable of stimulating or inhibiting the growth of other plants. The objective of this work was to evaluate the allelophatic action of the white sucupira (Pterodon emarginatus stem extract on the germination and development of colonião grass (Panicum maximum under germination, root and aerial part development of coloni

  2. 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

  3. Effects of Tagetes patula Mixed Planted with Rosa chinensis on Macrosiphum rosirvorum Zhang%孔雀草与月季混栽对月季长管蚜的影响

    Institute of Scientific and Technical Information of China (English)

    冯丹; 杨斌

    2011-01-01

    研究了孔雀草与月季混栽后对月季长管蚜的影响.结果表明,月季与孔雀草混栽对蚜虫控制作用明显,与未混栽的月季相比,混栽组月季长管蚜种群数量减少55.90%~77.27%.嗅觉行为试验显示,混栽后月季叶片有32%~45%蚜虫选择,未混栽的有55%~65%选择,显然,通过孔雀草的化感作用,月季叶片挥发性成分改变,时月季长管蚜引诱能力降低:嗅觉行为试验还显示,孔雀草散发的气味物质对月季长管蚜寄主选择有明显干扰或者掩盖作用,孔雀草与月季叶片混合后,月季长管蚜选择混合气味的最高比例为36.16%,最低比例仅为20.00%.而选择纯月季叶片的比例最高可迭80.03%,最低也达到63.84%.%The influence of mixed planting of Rosa chinensis (Hotpink) and Tagetes patula on Macrosiphum rosirvorum Zhang was investigated. It was confirmed that Hotpink planted with T. patula could obviously control the number of M. rosirvorum.The population of M. rosirvorum on mixed planted Hotpink group reduced by 55.90%~77.27% compared with the sole planted Hotpink. Olfactory test showed that the leaves of the Hotpink mixed planted with T. patula were selected by 32%~45% aphids; while the sole planted Hotpink were selected by 55%~65% aphids. Obviously, interaction of Hotpink and T. patula via allelopathy could change the volatile of Hotpink and lower its attraction to M. rosirvorum. The olfactory test also indicated that the odor substances came from T. patula had conspicuously interferential or masking effects on host selection of M.rosirvorum. After the mixing of T. patula and Hotpink leaves. the proportion that the mixed leaves were selected by M.rosirvorum was 20.00%~36.16%. Meanwhile, the proportion that sole planted Hotpink leaves were selected bv M. rosirvorumwas as high as 63.84%~80.03%.

  4. Study on Germination Characteristics of Perilla frutescens under Simulation Environment of Acid Rain and Bryophyta%模拟酸雨及苔藓植物化感条件下紫苏种子萌发特性的研究

    Institute of Scientific and Technical Information of China (English)

    谢天; 江安娜; 王曼君; 颜凤; 方元平; 项俊

    2012-01-01

    通过模拟酸雨胁迫及苔藓化感作用两种不同的生长环境,初步探讨了模拟酸雨及3种苔藓凤尾藓(Fissidens bryoides)、提灯藓(Mnium hornum)、缩叶藓(Ptychomitrium)种植水对紫苏(Perilla frutescens)种子萌发特性的影响.结果表明,pH为5.0及以上的低浓度模拟酸雨环境对紫苏种子的萌发及幼苗生长影响不大,但随着酸化程度的加深,对紫苏种子萌发的抑制作用明显增加,当pH降到1.0时种子不发芽.紫苏幼苗叶片POD活力随胁迫时间的延长呈先升后降的趋势.而叶片MDA含量除pH为5.0处理组与对照组相近外,其他胁迫浓度下均有显著增加,说明pH低于5.0紫苏幼苗生长受到较严重损害.在苔藓种植水培养环境中,与对照组相比,紫苏种子发芽率、发芽指数、活力指数均随苔藓植物种植水浓度的升高而升高,在浓度为100%时对种子萌发的促进效果最为显著.%By simulating two different growth environment, acid rain stress and moss allelopathy, the effects of acid rain and three bryophyte cultivate water (Fissidens bryoides ,Mnium hornum,Ptychomitrium) on Perilla frutescens seed germination was studied. The results showed that the simulated acid rain with pH lower than 5.0 had little effect on P. frutescens seed germination and seedling growth; as the increasing of acidification, there was a significant inhibition of seed germination, and the seed could not germinate under the pH lower than 1.0. The POD activity in P. frutescens blade increased firstly and then decreased as the stress time prolonged, and the MDA content was decreased when pH was lower than 5.0, suggesting that P. frutescens seedling growth was affected by pH lower than 5.0. In the culture water environment, compared to the control, P. frutescens germination rate, germination index, vigor index increased as the bryophyte planting concentration increasing, and the treatment with the most significant effect was 100% bryophyte planting

  5. The Interactions between Prorocentrom micans and Skeletonema costatum in Laboratory Cultures%实验条件下原甲藻与中肋骨条藻种间相互作用研究

    Institute of Scientific and Technical Information of China (English)

    钟恢明; 张健; 刘力章

    2011-01-01

    Algal allelopathy is a manifold ecological/physiological phenomenon which plays a crucial role in explaining microalgae distribution,community structure and the dynamics of populations within an ecosystem.In this article,interactions between Prorocentrum micans and Skeletonema costatum,causative red tide dinoflagellates,were investigated using bi-algal cultures under stable environmental conditions(temperature,light and illuminating periodicity,etc.) and sufficient nutrition supply by f/2 enrichment.The results showed that the growth of P.micans was not significantly different when cultured with S.costatum both in 1×104 cells/mL cell densities(F=0.004 48,P=0.947 960.05),whereas the growth of S.costatum was not inhibited when cultured with P.micans in 1×104 cells/mL inoculation density(F=5.116 63,P=0.047 210.05).Culture filtrate of P.micans induced no inhibitory effect on the growth of S.costatum,and similarly when separated by a membrane filter,S.costatum grew well when cultured in filtrate of P.micans-S.costatum,which implies that the inhibitory effect of P.micans on S.costatum in the bi-algal cultures occurred mainly by direct cell contact.The growth of P.micans and S.costatum in bi-algal cultures was simulated using a mathematical model(Lotka-Volterra) to quantify the interaction.It is indicated that P.micans outcompeted S.costatum over time.The algal interactions between P.micans and S.costatum may play an important role during the process of red tides algal species singularity and succession.%微藻化感作用是一种极其复杂的生理、生态学现象,其在解释微藻藻种分布、群落结构及种群动力学方向起着关键作用。选择我国典型常见赤潮优势种原甲藻(Prorocentrum micans)与中肋骨条藻(Skeletonemacostatum)作为对象,研究实验室共培养条件下2种微藻种间相互作用关系。结果表明:两者以1×104 cells/mL的密度接种共培养时,原甲藻的生长状况

  6. Factors affecting seedling regeneration of Liquidambar formosana in the L.formosana forests in hilly regions of Southeast Hubei,China%鄂东南低丘地区枫香林下枫香幼苗更新限制因子

    Institute of Scientific and Technical Information of China (English)

    王传华; 李俊清; 陈芳清; 杨莹

    2011-01-01

    Aims Liquidambarformosana is an important canopy tree species widely distributed in the plains and mountains from the north-subtropical zone to the tropical zone in China. Full understanding of the natural regeneration processes of tree seedling and limiting factors is important for plant population conservation and forest management. Our objective is to investigate the factors that limit seedling regeneration ofL. formosana under canopies of Formosan sweetgum forests in hilly regions of Southeast Hubei, China.Methods Seedling regeneration of L. formosana occurs sporadically under canopies of mixed pine forests but poorly under Formosan sweetgum canopy. In 2008, we carried out a series of experiments to study factors limiting seedling regeneration of L. formosana under mixed pine forests and Formosan sweetgum forests and tested: (1) effects of lower temperature and soil moisture on seed longevity, (2) effects of forest type, soil type and litter cover on seed survival, (3) litter allelopathy effects on seed longevity and germination, and (4) effects of light intensity under canopies on seedling survival.Important findings Dispersed seeds of L. formosana could germinate immediately at lower temperatures (4-8℃), although such temperatures were fatal to seedling establishment. Contrary to our prediction, soil type, litter leachate and litter cover had no effects on L. formosana seed viability and could not be used to explain poor seedling regeneration under canopies of Formosan sweetgum forest. We also did not find any litter leachate inhibition or promotion effects on seed germination, although a short germination lag effect was found with leachate of pine needles and sweetgum leaves. Shading first-year seedlings of L. formosana indicated that about 90% would die under the canopy of the Formosan sweetgum forest (with its 3% transmittance of open-sky light). In general, our experiments suggested that non-dormant seed and shade-intolerant seedlings of L

  7. Advances in the research of methane oxidation in forest soils%森林土壤氧化(吸收)甲烷研究进展

    Institute of Scientific and Technical Information of China (English)

    邓湘雯; 杨晶晶; 陈槐; 黄志宏; 项文化; 彭长辉

    2012-01-01

    Methane (CH4) is an important greenhouse gas, which is second only to carbon dioxide and about 25% contribution to global warming. Atmospheric methane can be oxidized by methanotrophic bacteria under aerobic condition. There are numerous reports of atmospheric CH4 oxidation and absorption in forest soils. Methanotrophic bacteria are a group of bacteria physiologically defined by their ability to use methane as sole source of carbon and energy for growth. However, it remains considerable uncertainty about the amounts of CH4 released from forest soils to the atmosphere, which depended on the abundance and relative activity of methanogenus and methanotrophic bacteria in forest ecosystems. Most studies have been focused on the environmental effects on the oxidizability and the biochemical properties of methanotrophic bacteria. The oxidation processes were a kind of high capacity and low affinity oxidation, affected by lots of factors, such as soil temperature, soil aeration, soil pH and nitrogen fertilizer. Generally, soil aeration was influenced by soil texture and soil moisture. And soil bulk density, soil structure and moisture were also influenced by land use types, and thereby affecting soil methane oxidation. Soil methane oxidation capacity also could be influenced by plants through changes in habitat or allelopathy. Few studies on soil animals, only termites in the emissions inventory is included in the global methane accounting. Starting from the classification of the methane-oxidizing bacteria, the methanotrophs on methane oxidation mechanism, the ecological distribution of the bacteria and methane oxidation factors, spatial and temporal heterogeneity, observation methods are reviewed. So, this review could provide a theoretical basis to correctly understand and accurately predict forest soil methane oxidation under the conditions of a certain type of climate and land use intensity.%甲烷是一种重要的温室气体,对全球气

  8. 紫茎泽兰入侵过程中生物群落的交互作用%The interaction between biological communities in the process of invasion of Ageratina adenophora

    Institute of Scientific and Technical Information of China (English)

    张红玉

    2013-01-01

    strong allelopathy. 3) Influences soil animal communities by changing the surface habitat and associated litter. 4) Due to changes in composition and function of soil microbial community,changes the form and quantity of available resources of soils , influences and reshapes the biological species interaction model, dynamic feedbacks to the formation of the new pattern of plant community. Then, the paper analyzed and pointed out: 1) In the process of biological invasion, the interaction effect plays an important role in the ecological change of plant community structure and function by the ecological process of multiple levels. 2) An ecological driving force was produced because of the impact of biological invasion on communities, then, it feedback effect to the remodeling of community interaction patterns and reconstruction of the new pattern of community and ecosystem. The complexity of biological invasion on community impact and future developments about the effects of biological invasion on communities and ecosystem were pointed out.

  9. 核桃凋落叶分解对3种作物生长、光合及抗性生理特性的影响%Effects of Decomposing Walnut (Juglans regia) Leaf Litter on Growth, Photosynthesis and Resistance Physiology of Three Recipient Plants

    Institute of Scientific and Technical Information of China (English)

    张如义; 胡红玲; 胡庭兴; 杨丽妹; 舒兰; 阮若玉

    2016-01-01

    采用盆栽试验,研究了核桃( Juglans regia)凋落叶在土壤中分解对3种受体作物萝卜( Raphanus sativus)、芥菜( Brassica juncea)和白菜( Brasicca pekinensis)生长、光合及抗性生理特性的影响,并比较不同受体作物对核桃凋落叶化感作用的敏感性,筛选可能与核桃套作的作物。试验设置4�5( T1)、9�0( T2)和18�0 g·盆-1( T3)3个凋落叶添加水平,对照( CK)不添加凋落叶。结果表明:(1)核桃凋落叶在其分解过程中对3种受体作物各项生长指标均表现出抑制作用,随着凋落叶量的增加抑制效应逐渐增强,而随着分解时间的延长抑制效应呈减弱趋势;(2)凋落叶分解80 d时,各处理3种受体作物叶片中的叶绿素和类胡萝卜素含量明显低于CK。各植物叶片净光合速率、气孔导度和蒸腾速率均显著低于CK;(3)与CK相比,各凋落叶处理3种受体作物叶片丙二醛含量增加,过氧化物酶和过氧化氢酶活性表现为受抑制作用,而超氧化物歧化酶活性表现为促进作用,可溶性糖含量增加,可溶性蛋白含量降低;(4)3种受体作物对核桃凋落叶化感综合抑制作用的敏感程度由大到小依次为白菜、萝卜和芥菜。综合各项指标可见,核桃凋落叶在分解初期(约80 d时)对3种受体作物产生了强烈的化感作用,主要通过氧化损伤、抑制叶绿素合成和降低其光合能力来阻碍其生长,之后随着凋落叶的进一步分解,释放的化感物质越来越少,对3种受体作物生长的抑制作用减弱。%A pot experiment was conducted to study effects of decomposing walnut leaf litter on growth, photosynthesis and resistant physiology of three recipient crops, i.e. radish (Raphanus sativus), mustard (Brassica juncea) and Chinese cab⁃bage ( Brasicca pekinensis) , and to compare the three crops in sensibility to allelopathy of the

  10. Research progress and prospect about exotic invasive species Phalaris minor Retz%外来入侵植物小子虉草研究进展与展望

    Institute of Scientific and Technical Information of China (English)

    徐高峰; 申时才; 张付斗; 张云; 毛佳; 金桂梅

    2015-01-01

    interested in studying this weed species and thus much progress has been made in understanding the biology and ecology of this species of weeds. However, research on P. minor in China has remained largely inadequate, resulting in difficulties in developing reliable early warning and control system for the weed. This paper reviewed some of the hot research issues on P. minor based on the abroad and domestic research results, including its distribution all across the world, the possible reasons for the damage it caused to crops (e. g. interspecific competition, allelopathy), the mechanisms underlying its invasion and spread, genetic variations in the weed population, and the highly adaptive ability and biological characteristics of the invasive weed to explain its highly successful rate of spread (e. g., morphological similarity of P. minor with wheat, small seed size and persistent soil seed bank). The paper also reviewed control methods of P. minor, which were divided into three general categories — manual, chemical and biological. Finally, three areas of future research were proposed: 1) multi-disciplinary mechanisms underlying its invasion and spread; 2) eco-physiological adaptation of the invasive species to global climate change;and 3) effective control of the invasive species. Thus it was very important to build an in-depth research on the invasive species in order to predict and prevent the successful invasion of P. minor, and to eventually lay the theoretical and technical support for the management of P. minor.

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

    Institute of Scientific and Technical Information of China (English)

    缪丽华; 王媛

    2012-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    李稹; 黄娟; 姜磊; 徐文杰; 王其东; 陈曦

    2012-01-01

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

  13. GC-MS identification of chemicals in lily root exudates%百合根系分泌物的GC-MS鉴定

    Institute of Scientific and Technical Information of China (English)

    程智慧; 徐鹏

    2012-01-01

    lower than 0.20%,11 organic compounds were identified in methanol component,mainly derivatives of parabens such as 1,2-benzenedicarboxylic acid,diisooctyl ester(52.11%) and bis(2-ethylhexyl) phthalate(40.95%),and the contents of other compounds were lower than 1%.Six derivatives of parabens were identified in petroleum ether component,such as 1,2-benzenedicarboxylic acid,diisooctyl ester(88.04%),bis(2-ethylhexyl) phthalate(9.06%),and the contents of other parabens were lower than 1%.There were abundant organic compounds identified in chloroform component,totally 19 compounds included esters,aldehyde,phenol,olefin,alkane,and so on.Among them,the contents of the following compounds were over than 1%:1,2-benzenedicarboxylic acid,diisooctyl ester(39.87%),Bis(2-ethylhexyl) phthalate(39.62%),hexadecane(1.36%),2-methoxy-1-(2-nitroethenyl)-3-(phenylmethoxy)-benzene(1.22%),phenol,2,4-bis(1,1-dimethylethyl)(1.02%).The allelopathy of diethyl ether component and the ethyl acetate component were weak and the organic compounds in the two components were not further identified.【Conclusion】 The organic compounds in lily root exudates identified by GC-MS are mainly esters.The higher level compounds in all the three components are the derivatives of parabens.Also there are few aldehyde,phenol and olefin.

  14. Effects of Applying Accumulator Straw in Soil on Growth and Cadmium Accumulation of Galinsoga parviflora%土施富集植物秸秆对牛膝菊生长及镉积累的影响

    Institute of Scientific and Technical Information of China (English)

    汤福义; 林立金; 廖进秋; 廖明安; 何静; 杨代宇; 张潇

    2015-01-01

    To study the allelopathy effects of accumulator straw on hyperaccumulator,a pot experiment was con-ducted to study the effects of applying accumulators (Conyza canadensis,Cardamine hirsuta,Eclipta prostrata and Nasturtium officinale)straws in soil on growth and cadmium accumulation of Galinsoga parviflora under cadmium pollution.The results were as follows:Compared with non-application (control),the application of C.canadensis and C.hirsute straws improved the roots,stems,leaves,shoots and whole plants biomasses of G.parviflora,and the plant height and antioxidant enzymes (SOD,POD and CAT)activity of G.parviflora also increased.The straws of E.pros-trate and N.officinale reduced the biomass,plant height and antioxidant enzyme activity of G.parviflora.The straws of C.canadensis,C.hirsuta,E.prostrata and N.officinale improved cadmium content in shoots of G.parviflora,which improved 1 2.01 %,9.55%,22.03% and 5.39% respectively compared with control,but only C.canadensis and C.hirsuta straws improved the cadmium accumulation in shoots of G.parviflora (which improved by 35.78% and 1 1 .77% respectively compared with control).C.canadensis and C.hirsuta straws increased soil catalase activity, soil urease activity and soil invertase activity,and the straws of E.prostrata and N.officinale reduced soil activity. Therefore,the applying C.canadensis and C.hirsuta straws in soil could improve cadmium contaminated soil remedy ability of G.parviflora,and C.canadensis straw was the best one.%为研究富集植物秸秆对超富集植物的化感作用,通过盆栽试验,研究了镉污染条件下,土施4种镉富集植物(小飞蓬、碎米荠、旱莲草和豆瓣菜)秸秆对牛膝菊生长及镉积累的影响。结果表明:与未施用相比,施用小飞蓬和碎米荠秸秆提高了牛膝菊根系、茎秆、叶片、地上部分及整株生物量,也提高了牛膝菊株高和抗氧化酶(SOD、POD 和CAT)活性,但施用旱莲草和豆瓣菜秸秆

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

    Institute of Scientific and Technical Information of China (English)

    孙小霞; 王海斌; 何海斌; 陆锦池; 林文雄

    2014-01-01

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

  16. Padrão de resposta de Mimosa pudica e Senna obtusifolia à atividade potencialmente alelopática de espécies de Poaceae Response pattern of Mimosa pudica e Senna obtusifolia to potentially allelopathic activity of Poaceae species

    Directory of Open Access Journals (Sweden)

    A.P.S. Souza Filho

    2010-01-01

    Full Text Available A alelopatia é um importante mediador de interferências que alteram a dinâmica de espécies de plantas em sistemas agrícolas. Neste trabalho, procurou-se determinar a existência de padrão de respostas das plantas daninhas Mimosa pudica e Senna obtusifolia a espécies da família Poaceae, via interação entre espécies e frações e ordenamento dos efeitos. Bioensaios de germinação de sementes e alongamento da radícula e do hipocótilo foram desenvolvidos, em condições controladas. Os testes foram realizados utilizando-se extratos hidroalcoólicos na concentração de 1,0% das frações folha, raiz e sementes de quatro espécies de Poaceae. Diferenças na intensidade dos efeitos para os fatores espécie e fração foram verificadas. O padrão de atividade observado foi de Paspalum maritimum apresentar as inibições mais intensas. Entre as espécies de Brachiaria, as inibições mais intensas foram produzidas por B. brizantha. Houve resposta efetiva para a especificidade entre espécies e fração para a germinação e alongamento da radícula, especialmente na espécie Mimosa pudica. Apenas para os extratos de P. maritimum foram observadas especificidade e efetividade em relação à germinação de sementes e alongamento da radícula da espécie Senna obtusifolia. A fração folha foi mais efetiva nas inibições, sobretudo na espécie P. maritimum. Comparativamente, a espécie Mimosa pudica foi mais sensível aos efeitos dos extratos, especialmente em relação ao desenvolvimento da radícula e do hipocótilo. A intensidade dos efeitos alelopáticos variou na seguinte ordem: alongamento da radícula > germinação de sementes > alongamento do hipocótilo. A ordenação dos resultados, para os indicadores de inibição, indicou discriminação no padrão para as espécies receptoras, o que sugere especificidade dos extratos.Allelopathy is an important device to measure interferences affecting the dynamics of plant species in

  17. Efeito alelopático de folhas de Solanum lycocarpum A. St.-Hil. (Solanaceae na germinação e crescimento de Sesamum indicum L. (Pedaliaceae sob diferentes temperaturas Allelopathic effect of Solanum lycocarpum A. St.-Hil. leaves on the germination and growth of Sesamum indicum L.(Pedaliaceae under different temperatures

    Directory of Open Access Journals (Sweden)

    Sarah C. Caldas Oliveira

    2004-09-01

    Full Text Available Alelopatia pode ser definida como o efeito maléfico ou benéfico que uma planta exerce sobre a outra por meio de compostos químicos liberados no ambiente. Diversas espécies do gênero Solanum apresentam evidências de propriedades alelopáticas. S. lycocarpum A. St.-Hil (lobeira é espécie de ampla distribuição em ambientes perturbados do Cerrado. No presente trabalho foram investigados efeitos alelopáticos de extratos de folhas de lobeira na germinação e no crescimento do gergelim (Sesamum indicum L.. Extratos aquosos das folhas foram preparados nas concentrações de 1%, 2%, 3%, 4% e 5% (p/v. A osmolaridade dos extratos foi medida e soluções de polietileno glicol (PEG 6000, de osmolaridade similar, foram preparadas para avaliar possíveis efeitos osmóticos dos extratos aquosos. Nos testes de germinação, as sementes de gergelim foram colocadas em placas de Petri forradas com papel de filtro com a solução a ser testada e observadas a cada 8h. Para os experimemtos de crescimento, sementes de gergelim foram germinadas em água e posteriormente dispostas para crescimento nos extratos. Após 5 dias, foram medidos os comprimentos da parte aérea e radicular das plântulas. Todos os experimentos foram conduzidos a 22 ºC, 30 ºC e 38 ºC. Observou-se que os extratos de folhas não afetaram a germinabilidade, mas aumentaram o tempo médio de germinação em uma relação próxima à dose-dependente, nas três temperaturas. Quanto ao crescimento, a parte radicular foi a mais afetada pelos extratos aquosos, apresentando redução no tamanho, necroses, ausência de pêlos absorventes e formação de raízes laterais. Os efeitos dos extratos no crescimento das plântulas foram mais evidentes a 38 ºC. Os experimentos conduzidos com soluções de PEG 6000 mostraram que os efeitos observados na presença dos extratos não são de natureza osmótica.Allelopathy should be defined as any stimulatory or inhibitory effect by one plant on another

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

    Institute of Scientific and Technical Information of China (English)

    周艳; 陈训; 韦小丽; 伍庆; 李朝婵

    2015-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    胡忠良; 王亚男; 马丹炜; 陈斌; 何亚强; 周健

    2015-01-01

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