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1.
Plant allelochemical interference or soil chemical ecology? 总被引:1,自引:0,他引:1
While allelopathy has been defined as plant-plant chemical interference, there has been much confusion about what the concept encompasses and how important it is in nature. We distinguish between (1) direct plant-plant interference mediated by allelochemicals, and (2) the effects of secondary compounds released by plants on abiotic and biotic soil processes that affect other plants.It very difficult to demonstrate direct effects of chemicals released by a plant on nearby plants. Although soil ecology-mediated effects of secondary plant compounds do not fit the classical concept of allelopathy, we find support in the literature for the hypothesis that the most important effects of compounds released into the soil environment by plants on other plants occur through such indirect effects. The emphasis on, and skepticism of, direct plant-plant allelopathic interference has led some researchers to demand unreasonably high standards of evidence for establishing even the existence of allelopathic interactions, standards that are not demanded for other plant-plant interactions such as resource competition. While the complete elucidation of the mechanisms by which allelochemicals function in the field is many years away, such elucidation is not necessary to establish the existence of allelopathic interactions.We propose that most of the phenomena broadly referred to as allelopathic interference are better conceptualized and investigated in terms of soil chemical ecology. Even when direct plant-plant allelochemical interference occur, the levels of allelochemicals in the environment and their effects on plants are heavily influenced by abiotic and biotic components of the soil ecosystem. Putting allelopathy in the context of soil ecology can further research and reduce some of the less fruitful controversy surrounding the phenomenon. 相似文献
2.
植物化感物质及化感潜力与土壤养分的相互影响 总被引:10,自引:0,他引:10
植物化感作用与许多生态因子有关.土壤养分缺乏,影响着许多植物化感物质的产生,从而影响植物的化感潜力;反过来,植物化感物质也通过络合、吸附、酸溶解、竞争、抑制等方式影响土壤的养分形态和水平.本文总结了植物化感物质及化感潜力与土壤养分的相互影响,并提出了今后该领域值得进一步研究的问题.包括以下几方面:加强植物化感研究与土壤 植物营养学研究的结合,以更深入地阐明植物化感物质、化感作用与土壤养分变化的关系;加强植物化感研究与生态系统养分循环研究的结合,以类似自然(nature-like)的方式模拟自然界植物所受的养分干,使养分干扰的化感研究结果更加逼真、可靠;加强对养分过量及受污染时植物化感作用的研究,为揭示农业和林业生产中植物的相互作用机制和生物量变化机制提供新的思路,为生态保护提供科学依据. 相似文献
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Allelopathy is defined as mechanism of plant-plant, plant-microorganisms, plant-virus, plant-insect, and plant-soil-plant
interactions mediated by plant- or microorganism-produced chemicals released to the environment. The majority of allelochemicals
are secondary metabolites and among others belong to terpenoids, phenolic compounds, organic cyanides and longchain fatty
acids. The action of allelochemicals in target plant is diverse and affects a large number of biochemical reactions resulting
in modifications of different physiological functions. Thus the results of allelochemical action can be detected at different
levels of plant organization: molecular, structural, biochemical, physiological and ecological. Enzyme activities, cell division
and ultrastructure, membrane permeability, ion uptake and as a consequence plant growth and development are modified by allelochemicals.
Significant effects on photosynthesis and respiration are the best-characterized results of allelopathic interactions. Moreover
allelopathic compounds seem to induce a secondary oxidative stress expressed as enhanced free radical production and induction
of cellular antioxidant system. Plant survival under allelopathy stress conditions depends on plant defense leading to allelochemical
detoxication, the process which may go on in parallel to cell defense reaction to oxidative stress.
The article presents some aspects of the current knowledge regarding mechanisms of the allelopathy phenomenon. The allelopathy
is a complex problem, thus comprehensive understanding of allelochemical mode of action requires further investigation and
still remains an open question. 相似文献
5.
菊科植物化感作用研究进展 总被引:60,自引:3,他引:57
对菊科植物化感作用的研究进展进行了综述。菊科植物中至少有 39个属存在化感作用 ,特别是一枝黄花属、向日葵属、胜红蓟属、银胶菊属、蒿属植物等有较多的研究报道。鉴定出的化感物质多为萜类、聚乙炔类、酚类、有机酸类等 ,这些化感物质对多种受体植物表现出程度不同的抑制或促进的效应。其化感作用机理表现在破坏受体膜系统的稳定性及水分平衡关系、抑制氧化磷酸化、促进或阻滞叶绿素的合成、影响矿质元素的吸收利用等。并对菊科植物化感物质在植物生长调节剂、天然除草剂和生物杀虫剂 ,或人工合成除草剂和杀虫剂上应用的前景进行了探讨。本文显示菊科植物的化感作用将在控制外来恶性杂草及维护生态平衡上扮演重要的角色。在当前菊科植物化感作用研究的基础上 ,提出了进一步研究的 6个方向 :(1)化感物质的生物合成途径与关键酶的特性研究 ;(2 )具化感潜势物种资源的调查评价及利用研究 ;(3)化感作用在自然生态系统中的演变规律 ;(4 )菊科重要作物自毒的生化机制及克服途径 ;(5 )具应用前景的菊科植物化感关键酶的基因克隆和转基因 ,并对受体植物基因的表达与调控进行研究 ;(6 )化感作用在可持续发展农业应用上的研究与开发 ,特别是作为天然除草剂及杀虫剂 相似文献
6.
Plant phenolics in allelopathy 总被引:3,自引:0,他引:3
Inderjit 《The Botanical review》1996,62(2):186-202
Phenolics are one of the many secondary metabolites implicated in allelopathy. To establish that allelopathy functions in a natural ecosystem, the allelopathic bioassay must be ecologically realistic so that responses of appropriate bioassay species are determined at relevant concentrations. It is important to isolate, identify, and characterize phenolic compounds from the soil. However, since it is essentially impossible to simulate exact field conditions, experiments must be designed with conditions resembling those found in natural systems. It is argued that allelopathic potential of phenolics can be appreciated only when we have a good understanding of 1) species responses to phenolic allelochemicals, 2) methods for extraction and isolation of phenolic allelochemicals, and 3) how abiotic and biotic factors affect phenolic toxicity. 相似文献
7.
The fungal fast lane: common mycorrhizal networks extend bioactive zones of allelochemicals in soils
Allelopathy, a phenomenon where compounds produced by one plant limit the growth of surrounding plants, is a controversially discussed factor in plant-plant interactions with great significance for plant community structure. Common mycorrhizal networks (CMNs) form belowground networks that interconnect multiple plant species; yet these networks are typically ignored in studies of allelopathy. We tested the hypothesis that CMNs facilitate transport of allelochemicals from supplier to target plants, thereby affecting allelopathic interactions. We analyzed accumulation of a model allelopathic substance, the herbicide imazamox, and two allelopathic thiophenes released from Tagetes tenuifolia roots, by diffusion through soil and CMNs. We also conducted bioassays to determine how the accumulated substances affected plant growth. All compounds accumulated to greater levels in target soils with CMNs as opposed to soils without CMNs. This increased accumulation was associated with reduced growth of target plants in soils with CMNs. Our results show that CMNs support transfer of allelochemicals from supplier to target plants and thus lead to allelochemical accumulation at levels that could not be reached by diffusion through soil alone. We conclude that CMNs expand the bioactive zones of allelochemicals in natural environments, with significant implications for interspecies chemical interactions in plant communities. 相似文献
8.
Bioassays and Field Studies for Allelopathy in Terrestrial Plants: Progress and Problems 总被引:1,自引:0,他引:1
Bioassays are an integral part of allelopathy research. The unsuitability of laboratory bioassays to explain field situations is discussed previously. In this article, we discuss progress in bioassay experimental design and several unresolved problems associated with research on allelopathy. The objectives of this article are to discuss problems related to (1) collection of allelopathic material for bioassay, (2) allelochemical quantification in bioassays, (3) selection of concentration of allelochemicals in bioassay, (4) selection of appropriate control, (5) interaction between allelochemicals and other substances, and (6) in situ allelochemical bioassays. We concluded that new experimental designs for in situ bioassay are needed that can account for the large number of confounding factors in a complex field environment, and can be linked to physiological monitoring of target species and biochemical monitoring of the growth medium. Referee: Dr. Stella Elakovich, Dept. of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS 390406-5043 相似文献
9.
The impact of allelopathic, nonpathogenic bacteria on plant growth in natural and agricultural ecosystems is discussed. In some natural ecosystems, evidence supports the view that in the vicinity of some allelopathically active perennials (e.g., Adenostoma fasciculatum, California), in addition to allelochemicals leached from the shrub's canopy, accumulation of phytotoxic bacteria or other allelopathic microorganisms amplify retardation of annuals. In agricultural ecosystems allelopathic bacteria may evolve in areas where a single crop is grown successively, and the resulting yield decline cannot be restored by application of minerals. Transfer of soils from areas where crop suppression had been recorded into an unaffected area induced crop retardation without readily apparent symptoms of plant disease. Susceptibility of higher plants to deleterious rhizobacteria is often manifested in sandy or so-called skeletal soils. Evaluation of phytotoxic activity under controlled conditions, as well as ways to apply allelopathic bacteria in the field, is approached. The allelopathic effect may occur directly through the release of allelochemicals by a bacterium that affects susceptible plant(s) or indirectly through the suppression of an essential symbiont. The process is affected by nutritional and other environmental conditions, some may control bacterial density and the rate of production of allelochemicals. Allelopathic nonpathogenic bacteria include a wide range of genera and secrete a diverse group of plant growth-mediating allelochemicals. Although a limited number of plant growth-promoting bacterial allelochemicals have been identified, a considerable number of highly diversified growth-inhibiting allelochemicals have been isolated and characterized. Some species may produce more than one allelochemical; for example, three different phyotoxins, geldanamycin, nigericin, and hydanthocidin, were isolated from Streptomyces hygroscopicus. Efforts to introduce naturally produced allelochemicals as plant growth-regulating agents in agriculture have yielded two commercial herbicides, phosphinothricin, a product of Streptomyces viridochromogenes, and bialaphos from S. hygroscopicus. Many species of allelopathic bacteria that affect growth of higher plants are not plant specific, but some do exhibit specificity; for example, dicotyledonous plants were more susceptible to Pseudomonas putida than were monocotyledons. Differential susceptibility of higher plants to allelopathic bacteria was noted also in much lower taxonomical categories, at the subspecies level, in different cultivars of wheat, or of lettuce. Therefore, when test plants are employed to evaluate bacterial allelopathy, final evaluation must include those species that are assumed to be suppressed in nature. The release of allelochemicals from plant residues in plots of ‘continuous crop cultivation’ or from allelopathic living plants may induce the development of specific allelopathic bacteria. Both the rate by which a bacterium gains from its allelopathic activity through utilizing plant excretions, and the reasons for the developing of allelopathic bacteria in such habitats, are important goals for further research. 相似文献
10.
Weeds are known to cause enormous losses due to their interference in agroecosystems. Because of environmental and human health concerns, worldwide efforts are being made to reduce the heavy reliance on synthetic herbicides that are used to control weeds. In this regard the phenomenon of allelopathy, which is expressed through the release of chemicals by a plant, has been suggested to be one of the possible alternatives for achieving sustainable weed management. The use of allelopathy for controlling weeds could be either through directly utilizing natural allelopathic interactions, particularly of crop plants, or by using allelochemicals as natural herbicides. In the former case, a number of crop plants with allelopathic potential can be used as cover, smother, and green manure crops for managing weeds by making desired manipulations in the cultural practices and cropping patterns. These can be suitably rotated or intercropped with main crops to manage the target weeds (including parasitic ones) selectively. Even the crop mulch/residues can also give desirable benefits. Not only the terrestrial weeds, even allelopathy can be suitably manipulated for the management of aquatic weeds. The allelochemicals present in the higher plants as well as in the microbes can be directly used for weed management on the pattern of herbicides. Their bioefficacy can be enhanced by structural changes or the synthesis of chemical analogues based on them. Further, in order to enhance the potential of allelopathic crops, several improvements can be made with the use of biotechnology or genomics and proteomics. In this context either the production of allelochemicals can be enhanced or the transgenics with foreign genes encoding for a particular weed-suppressing allelochemical could be produced. In the former, both conventional breeding and molecular genetical techniques are useful. However, with conventional breeding being slow and difficult, more emphasis is laid on the use of modern techniques such as molecular markers and the selection aided by them. Although the progress in this regard is slow, nevertheless some promising results are coming and more are expected in future. This review attempts to discuss all these aspects of allelopathy for the sustainable management of weeds. Referee: Dr. Amrjits S. Basra, Central Plains Crop Technology, 5912 North Meridian Avenue, Wichita, KS 67204 相似文献
11.
Ana Luisa Anaya 《植物科学评论》1999,18(6):697-739
In modern agriculture, natural plant communities may be replaced by a single crop species. Weeds, some microorganisms, and viruses, as well as some herbivores are organisms that should be eliminated. Pesticides and fertilizers not only affect the pests and crops, but soil, non-pest species, water, food, and humans. In traditional agriculture weeds are components with an important ecological role in the maintenance of the system. Some weeds have been used as tools to control the growth of other weeds in traditional agroecosystems. Researchers on sustainable and organic agriculture get valuable information from traditional agriculture and currently are conducting research on plant breeding, soil fertility and tillage, crop protection, and cropping systems. Allelopathy and chemical ecology are directly involved in each of these fields and can play an important role in crop productivity, conservation of genetic diversity, and maintenance of ecosystems stability. Allelopathy has been shown to be related with problems of chemical interference between crops and weeds, crops and crops, toxicity of crops and weeds residues, and/or crops and weeds exudates. Problems of autotoxicity, orchard replanting, and forest regeneration are also referred as allelopathic. Allelopathy is strongly coupled with other stresses of the environment, including insects and disease, temperature extremes, nutrient and moisture variables, radiation, and herbicides. These stress conditions often enhance allelochemical production and increase the potential for allelopathic interference. Allelopathy offers potential for weed control through the production and release of allelochemicals from plants. Allelochemicals may impact the availability of nutrients through effects on the symbiotic microbes. Destruction and changes in the use of soils in the tropics have decreased biodiversity, bringing about the loss of valuable natural products. Many different types of useful products such as natural pesticides and drugs can arise from allelopathy studies. New methods must be generated for allelopathy as a part of the biotic resources management strategies. 相似文献
12.
小麦是世界第一大粮食作物,在农业生产中占有重要地位.然而,由于人们为保证小麦产量往往施用大量的除草剂和杀菌剂,对环境造成了极大的危害.小麦化感作用是利用小麦活体或残体向环境中释放次生代谢物质对自身或其他生物产生作用,它克服了除草剂和杀菌剂等引起的环境污染问题,具有抑制杂草控制病害的潜力.本文对已有的小麦化感作用的研究进展情况进行了综合评述.其中小麦对杂草、虫害及病害产生防御功能的主要化感物质为异羟肟酸和酚酸类物质.小麦化感物质活性的发挥除了取决于化感物质的种类外,还由小麦自身的遗传因素、环境因素和生物因素的共同作用所决定.小麦化感物质在根际土壤中的滞留、迁移和转化过程、小麦化感作用与土壤生物的关系以及相关的作用机理是小麦化感作用研究的薄弱环节,其研究方法还需进一步探索改进.小麦化感作用在植物保护、环境保护以及作物育种等方面具有广泛的应用前景,促进了小麦抗逆性的增强以及产量和品质的提高. 相似文献
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Can allelopathically active submerged macrophytes stabilise clear-water states in shallow lakes? 总被引:4,自引:0,他引:4
Inhibition of phytoplankton by allelochemicals released by submerged macrophytes is supposed to be one of the mechanisms that contribute to the stabilisation of clear-water states in shallow lakes. The relevance of this process at ecosystem level, however, is debated because in situ evidence is difficult to achieve. Our literature review indicates that allelopathically active species such as Myriophyllum, Ceratophyllum, Elodea and Najas or certain charophytes are among the most frequent submerged macrophytes in temperate shallow lakes. The most common experimental approach for allelopathic interference between macrophytes and phytoplankton has been the use of plant extracts or purified plant compounds. Final evidence, however, requires combination with more realistic in situ experiments. Such investigations have successfully been performed with selected species. In situ allelopathic activity is also influenced by the fact that phytoplankton species exhibit differential sensitivity against allelochemicals both between and within major taxonomic groups such as diatoms, cyanobacteria and chlorophytes. In general, epiphytic species apparently are less sensitive towards allelochemicals than phytoplankton despite living closely attached to the plants and being of key importance for macrophyte growth due to their shading. Light and nutrient availability potentially influence the sensitivity of target algae and cyanobacteria. Whether or not additional stressors such as nutrient limitation enhance or dampen allelopathic interactions still has to be clarified. We strongly propose allelopathy as an important mechanism in the interaction between submerged macrophytes and phytoplankton in shallow lakes based on the frequent occurrence of active species and the knowledge of potential target species. The role of allelopathy interfering with epiphyton development is less well understood. Including further levels of complexity, such as nutrient interference, grazing and climate, will extend this ecosystem-based view of in situ allelopathy. 相似文献
14.
Allelopathic substance in rice root exudates: rediscovery of momilactone B as an allelochemical 总被引:6,自引:0,他引:6
Kato-Noguchi H 《Journal of plant physiology》2004,161(3):271-276
Much research on rice allelopathy has been directed toward the selection of allelopathic rice strains and the identification of allelochemicals in rice. This paper briefly summarizes recent progress in the rice allelopathy and focuses on rediscovery of momilactone B as an allelochemical. A large number of rice varieties were found to inhibit the growth of several plant species when grown together under field and/or laboratory conditions. These findings suggest that rice probably produces and releases allelochemical(s) into the environment. The putative compound causing the inhibitory effect of rice was recently isolated from rice root exudates, and the chemical structure of the inhibitor was determined by spectral data as momilactone B. In addition, it has been found that momilactone B is released from rice roots into the neighboring environment, and the release level of momilactone B from rice may be sufficient to cause growth inhibition of neighboring plants. These findings suggest that momilactone B may play an important role in rice allelopathy. 相似文献
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小麦化感作用研究进展 总被引:31,自引:2,他引:29
小麦是世界第一大粮食作物,在农业生产中占有重要地位.然而,由于人们为保证小麦产量往往施用大量的除草剂和杀菌剂,对环境造成了极大的危害.小麦化感作用是利用小麦活体或残体向环境中释放次生代谢物质对自身或其他生物产生作用,它克服了除草剂和杀菌剂等引起的环境污染问题,具有抑制杂草控制病害的潜力.本文对已有的小麦化感作用的研究进展情况进行了综合评述.其中小麦对杂草、虫害及病害产生防御功能的主要化感物质为异羟肟酸和酚酸类物质.小麦化感物质活性的发挥除了取决于化感物质的种类外,还由小麦自身的遗传因素、环境因素和生物因素的共同作用所决定.小麦化感物质在根际土壤中的滞留、迁移和转化过程、小麦化感作用与土壤生物的关系以及相关的作用机理是小麦化感作用研究的薄弱环节。其研究方法还需进一步探索改进.小麦化感作用在植物保护、环境保护以及作物育种等方面具有广泛的应用前景,促进了小麦抗逆性的增强以及产量和品质的提高. 相似文献
17.
Yoshiharu Fujii 《Biological Sciences in Space》2003,17(1):6-13
We have studied on allelopathy of plants and developed methods to identify the effective substances in root exudates, leaf leacheate, and volatile chemicals emitted from plants. We found traditional cover plants that show allelopathic activity are useful for weed control. It could eliminate the use of synthetic chemicals for this purpose. Allelopathy is a natural power of plants to protect themselves by producing natural organic chemicals. Some endemic plants in Asia, already known by farmers in the region, as either cover crops used in intercropping, hedgerow, or agroforestry, were found to possess strong allelopathic abilities. Our group identified several allelochemicals from these plants. These allelopathic cover crops, mostly leguminous plants, provide protein rich food, and grow easily without artificial fertilizers, herbicides, insecticides and fungicides. In this regards, these allelopathic cover crops could save food shortage in rural area, and are useful for environmental conservation. Screenings of allelopathic plants by specific bioassays and field tests have been conducted. Hairy vetch (Vicia villosa) and Velvet bean (Mucuna pruriens) are two promising species for the practical application of allelopathy. An amino acid, L-DOPA, unusual in plants, plays an important role as allelochemical in Velvet bean (Mucuna pruriens). Hairy vetch is the most promising cover plant for the weed control in orchard, vegetable and rice production and even for landscape amendment in abandoned field in Japan. We have isolated "cyanamide", a well known nitrogen fertilizer, from Hairy vetch. This is the first finding of naturally produced cyanamide in the world. 相似文献
18.
探明野生杜鹃群落不同层次土壤浸提物的化学成分及其含量差异,为阐明杜鹃群落天然更新障碍与化感作用之间的关系提供基础数据,从化学生态学角度解释群落天然更新障碍的原因。通过种子发芽试验,比较凋落物层(L层)、腐殖质层(H层)和土壤表层(S层)浸提液对自身种子萌发的化感效应,采用内标法结合气相色谱-质谱(GC/MS)联用等技术鉴定土壤浸提液所含的有机化合物。(1)种子发芽试验显示,露珠杜鹃不同土壤层浸提液的化感效应不同。L层的抑制作用最为强烈,其浸提液显著抑制自身种子的萌发。H层和S层对自身具有一定的抑制作用,与对照相比不显著;(2)鉴定了不同层次土壤浸提液中所含的有机化合物,L层、H层和S层均检测出31种组分,其中相对含量大于5%的组分分别有6、8和8种。L层浸提液主要化感成分为丙三醇和棕榈酸,分别达到总量的19.56%和19.17%;H层主要化感成分为2-羟基丙酸和棕榈酸,分别达到总量的14.05%和12.48%;S层土壤浸提物的主要化感成分为棕榈酸和2-羟基乙酸,分别达到总量的14.91%和12.79%。野生露珠杜鹃不同土壤浸提物的化感物质含量以L层最高,L层作为群落土壤化感物质的主要来源;从化感物质组分来分,长链脂肪酸和有机酸类是H层和S层主要的化感物质种类,长链脂肪酸类和醇类是L层主要的化感物质种类。杜鹃群落林下土壤中存在的化感物质可能是其天然更新障碍的重要原因之一。 相似文献
19.
Chang-Hung Chou 《植物科学评论》1999,18(5):609-636
Allelopathic compounds are metabolites released from plants that might be beneficial or detrimental to the growth of receptor plants. These compounds are involved in the environmental complex of managed or natural ecosystems. Allelopathic compounds have been shown to play important roles in the determination of plant diversity, dominance, succession, and climax of natural vegetation and in the plant productivity of agroecosystems. The overuse of synthetic agrochemicals often causes environmental hazards, an imbalance of soil microorganisms, nutrient deficiency, and change of soil physicochemical properties, resulting in a decrease of crop productivity. The incorporation of allelopathic substances into agricultural management may reduce the use of synthetic herbicides, fungicides, and insecticides and lessen environmental deterioration. Scientists in many different habitats around the world have demonstrated the above examples previously. It is known that most volatile compounds, such as terpenoids, are released from plants in drought areas. In contrast, water-borne phytotoxins, such as phenolics, flavonoids, or alkaloids, are released from plants in humid zone areas. Both allelopathy and autointoxication play an important mechanism in regulating plant biodiversity and plant productivity. A unique case study of a pasture-forest intercropping system, which is particularly emphasized here, could be used as a model for forest management. After the deforestation of coniferous or hardwood forests, a pasture grass, kikuyu grass (Pennisetum clandestinum), was transplanted onto the land. The grass was quickly established within 6 months. Significant suppression of weed growth by the kikuyu grass was found; however, the growth of coniferous or hardwood plants was not suppressed but stimulated. This example as well as others described in this text clearly indicate that allelopathy plays a significant role in sustainable agriculture. Nevertheless, room for allelopathic research in the next century is available for biologists, biochemists, biotechnologists, and chemists. Future allelopathic research should focus on the following tasks: (1) a continuous survey of potential allelochemicals from natural vegetation or microorganisms, (2) the establishment of practical ways of using allelochemicals in the field, (3) to understand the mode of action of allelopathic chemicals in receptor organisms, (4) to understand the role of allelopathic chemicals in biodiversity and ecosystem function, (5) to explore advanced biotechnology for allocating allelopathic chemical genes in plants or microorganisms for biological control, and (6) to challenge the natural product chemists to develop a better methodology for isolating allelopathic compounds or their degraded compounds from the environment, particularly the soil environment. 相似文献
20.
Allelopathic potential in rice (Oryza sativa L.) germplasm 总被引:10,自引:0,他引:10