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Showing 1553 articles

April, 2011  Volume (27 - 2)
Allelopathy, arrowhead, Bioassay, HPLC, phenolic acids, rice (Oryza sativaL.), Sagittaria trifolia.
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Screening for Iranian rice allelopathic varieties by HPLC and bioassays
  • Pages - 193-206
  • SAMAN BERENJI, JAFAR ASGHARI*, AMIR ABBAS MATIN1and HABIBOLLAH SAMIZADEH
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  • View Abstract  The study on rice allelopathy is very recent in Iran, hence, till now the Iranian varieties with allelopathic potential have not been identified and categorized. The effects of hull water extracts was evaluated onthe seedling growth of arrowhead (Sagittaria trifolia) weed. The extracts of varieties ‘Dinorado’ and ‘Neda’ were most suppressive to arrowhead seedling growth than othervarieties. High performance liquid chromatography (HPLC) was used to analyze six phenolic acids in rice hull water extracts. Among the tested varieties, Dinorado variety hull extract had maximum phenolic acids content. None of the six phenolic acids were detected in extracts of Line-229 , while, Dashti-sard had highest (p)-hydroxy benzoic acid content. Of the 46 tested varieties, 10 were chosenand grown in hydroponics system to study effects of their root exudates on seedlinggrowth of arrowhead weed. Root exudates of Dinorado, Neda and IR-60 showed higher inhibitory activities against arrowhead seedling growth than other tested varieties. Both hull water extracts and root exudates of Dinorado proved most inhibitory toarrowhead weed growth. From Iranian rice germplasm, Neda cultivar had high allelopathic potential against arrowhead weed.


April, 2011  Volume (27 - 2)
3-Oxo-a-ionol, 9-hydroxy-4-megastigmen-3-one, barnyardgrass, BR17 rice, cress, growth inhibition.
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Isolation and characterisation of two potent growth inhibitory substances from aqueous extract of Bangladeshi rice cultivar BR17
  • Pages - 207-216
  • MD ABDUS SALAM and HISASHI KATO-NOGUCHI*
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  • View Abstract  Allelopathy and allelopathic substances in high yielding Bangladeshi rice cultivar BR17 were investigated. An aqueous extractof BR17 rice (Oryza sativaL.) inhibited the seedling growth of cress (Lepidium sativumL.), lettuce (Lactuca sativaL.), alfalfa (Medicago sativaL.), timothy (Phleum pratenseL.), crabgrass (Digitaria sanguinalisL.), ryegrass (Lolium multiflorumL.), barnyardgrass (Echinochloa crus-galli[L.] Beauv.) and Echinochloa colonum(L.) Link. Increasing the extract concentration increased the inhibition. These results suggest that BR17 may possess allelopathic potential and allelopathic substances.The aqueous extract was purified and two growth inhibitory substances were isolated and identified by their 1H-NMR spectral data as 3-oxo-a-ionol and 9-hydroxy-4-megastigmen-3-one. The concentrations required for 50 % growth inhibition of 3-oxo-a-ionol were 2.51 and 2.15 µM for cress roots and hypocotyls, respectively, and 16.3 and 134 µM for barnyardgrass roots and shoots, respectively. The concentrations required for 50 % growth inhibition of 9-hydroxy-4-megastigmen-3-one were 0.49 and 0.25 µM for cress roots and hypocotyls, respectively, and 30.2 and 180 µM for barnyardgrass roots and shoots, respectively. These results suggest that 3-oxo-a-ionol and 9-hydroxy-4-megastigmen-3-one may contribute to thegrowth inhibitory effects of BR17 and may play important roles in allelopathy ofBR17.


April, 2011  Volume (27 - 2)
Allelopathy,Digitaria sanguinalis L., E. chinochloa crusgalli(L.), flower, GC-MS, leaf,Parthenium hysterophorusL., volatiles
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Allelopathic effects of Parthenium hysterophorusL. volatiles and its chemical components
  • Pages - 217-223
  • YEBING CHEN1,2, JINXIN WANG 1*, XIAOHU WU1, JIAN SUN1and NA YANG1
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  • View Abstract  We studied the allelopathic effects of volatiles from Parthenium hysterophorusL. on the seedling growth of Echinochloa crusgalli(L.) Beauv. and Digitaria sanguinalis L. under laboratory and field conditions. The chemical components of volatiles were analysed using headspace method and gas chromatography-mass spectrometry (GC-MS). The seedling growth ofE. crusgalli and D. sanguinalisintercropped withP. hysterophorusin the field was significantly inhibited. Fresh P. hysterophorusflower enclosed in a transparent box inhibited the seedling growth ofE. crusgalliand D. sanguinalis. The enclosed fresh leaves of P. hysterophorus inhibited the seedling growth ofD. sanguinalis. The volatiles fromP. hysterophorusflowers contained 17 components. The main component in volatiles was myrcene (56.67%) and the second component was ocimene (26.28%). There were 18 components in the volatiles fromP. hysterophorus leaves. The main component in fresh leaf was myrcene (28.07%), the second was ß-pinene (14.52%). The volatiles contained high content of terpenoids, indicating that P. hysterophorusreleased its allelochemicals through volatilization. The allelopathy of volatiles may play an important role in enhancing the invasiveness of P. hysterophorusand may suppress other plant species in vicinity.


April, 2011  Volume (27 - 2)
Allelochemicals, germination, greengram, Green manuring, growth, Helianthus annuus , P. hysterophorus, rhizosphere soil
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Allelopathic effects of sunflower (Helianthus annuus) on germination and growth of Parthenium hysterophorus
  • Pages - 225-236
  • L. S. RAWAT1*, S. S. NARWAL2, H.S. KADIAN2 and V.S. NEGI1
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  • View Abstract  Investigations were done to determine the effects of sunflower rhizosphere soil (SRS) in pot culture and of sunflower green manuring (SGM) in field studies at 75, 90,105 and 120 days after sowing (DAS) on the germination and growth of Parthenium hysterophorus weed. Two cover crops greengram [(GG) (Vigna radiata)] and Pearl millet [(PM) (Pennisetum glaucum)] were used. Field experiments revealed that all growth and yield attributes of P. hysterophoruswere inhibited maximum at 75 DAS old SGM and in SGM + PM. The inhibitory effectsof sunflower decreased at later stages. Likewise in Pot experiments, SRS at 75 DAS proved most inhibitory to growth and yield attributes of P. hysterophorusthan at later stages. Allelochemicals were identified in sunflower crop by paper chromatography and spectroscopic analysis. These results suggested that sunflower green manuring and its rhizosphere soil has herbicidal potential and may be used for biological control of weeds for sustainable agriculture and to safeguard the environment


April, 2011  Volume (27 - 2)
Allelochemical, germination inhibition, hairy vetch, seed size, seed weight, small seed sensitivity,Vicia villosa.
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Hairy vetch (Vicia villosa) seed size affects germination response to coumarin
  • Pages - 237-244
  • R.D. WILLIAMS* and P.W. BARTHOLOMEW
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  • View Abstract  The inhibition of seed germination by an allelochemical is generally greater in small seeds than in large seeds. This response may have significant impact on weed control by allelopathic cover crops, where the small-seeded weeds would be more effectively controlled than large-seeded species. The studies reporting these results used a large number of plant species that varied in seed size, which might have introduced differences in germination characteristics or various parameters required for growth and emergence. One approach to avoid factors associated with the use of a mixed seed size population is to separate a large population of seeds from a single species into various size classes. This allows theanalysis of the effects of a given allelochemical directly as a function of seed size.Here, hairy vetch (Vicia villosaRoth.) seeds were separated into three classes based on their seed weight (large, 54 mg; medium, 40 mg; and small, 26 mg) and compared their germination response to coumarin at 10-3 and 10-5M. There was no significant difference in germination to 10-5M coumarin with respect to seed size. However, germination was reduced and delayed in seeds exposed to 10-3 M coumarin, and this effect was more noticeable in the small seed class. Expressed as a percent of control, germination for large, medium and small seeds was 72, 76, and 55% respectively and germination of small seeds was also delayed by two days. These results confirm that small seeds are more sensitive to an allelochemical and this sensitivity is selectivewithin a species with respect to small versus large seed. If expressed by a cover crop, this selection pressure could have significant impact on the weed community over time.


April, 2011  Volume (27 - 2)
Autotoxicity, germination index, Picea schrenkianaFisch. et Mey., seedling growth.
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Biological activity and quantification of potential autotoxins from Picea schrenkiana leaves
  • Pages - 245-262
  • Z.H. LI, Q. WANG1,4*, X. RUAN1, C.D. PAN2, J.C. ZHANG3, D.A. JIANG*and G.G. WANG4
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  • View Abstract  We studied the potential autotoxicity of aqueous extracts fromP. schrenkianaleaves. Water extract was partitioned against diethyl ether, ethyl acetate, and n-butanol sequentially. Inhibitory effects of 3-organic fractions [original water extract and the residual water (after the organic solvent extraction)] were tested on seed germination and seedling growth of P. schrenkiana. All 5-fractions (original water extract, diethyl ether fraction, ethyl acetate fraction and n-butanol fraction) showed different phytotoxic effects on seed germination and seedling growth. Diethyl ether fraction was most phytotoxic and inhibited the seedgermination and seedling growth at low concentration of 0.1 mg/mL. The chemical natureof the three organic fractions was also determined using GC-MS-MS and NMR. 17 secondary metabolites [p-hydroxybenzoic acid, 2-keto-4a-methyl-8-methoxy-2,3, 4, 4a, 5, 6, 11, 12-octa- hydrochrysene (named as schrenkianaone), cinnamic acid, abscisic acid (ABA), quercetin, umbelliferone, ß-phenyllactic acid, vanillic acid, gallic acid, myristic acid, gentisic acid, ß-resorcylic acid, indole-3-carboxaldehyde, p-coumaric acid, ethyl hematommate, esculetin and caffeic acid] were identified and quantified. Schrenkianaone, which had been found but not reported as an allelochemical previously, was detected in the diethyl ether fraction.


April, 2011  Volume (27 - 2)
Achaea janata L, antifeedant, castor, Dichocrocis punctiferalis, herbivory, HPLC, phenolics, ,Ricinus communis, Spodoptera litura.
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Allelochemicals in castor (Ricinus communis L.) plants and their impact on pest larval feeding as anti-herbivore defensive
  • Pages - 263-275
  • PATHIPATI USHA RANI* and M. V. RAVIBABU
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  • View Abstract  Among the chemical defensive strategies developed by the plant, leaf phenolics generated due to insect herbivory play a major role in controlling the herbivore damage. This study deals with the quantitative and qualitative changes in castor (Ricinus communisL) plant leaf phenolics due to the feeding of its major pests, the castor semilooper [Achaea janata(L.)],, tobacco caterpillar [Spodoptera litura (Fabricus)] and the capsule borer [Dichocrosis punctiferalis (Guenee)]. The foliar phenolics extracted from the pest damaged leaves were compared between the pests having different modes of feeding. These experiments revealed the presence of elevated levels of phenolic acid in insect infestedplants than uninfested plants. Seven individual phenolic acids were monitored by high performance liquid chromatography (HPLC) in pest damaged and normal healthy castor plant leaves and an increase in vanillic, coumaric, ferulic and syringic acids was noted in the insect infested plants. The impact of increased phenolics on pest feeding behaviour and the growth were analysed through antifeedant assays. A significant difference in the modification of phenolic acids between specialist and generalist leaf feeders was found.


April, 2011  Volume (27 - 2)
Allelochemicals, Alphitobius diaperinus, antifeedants, essential oils, Illicum verum, lesser mealworm, star anise fruits.
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Insecticidal activity of star anise (Illicum verumHook. F.) fruits extracts against lesser mealworm, Alphitobius diaperinus Panzer (Coleoptera: Tenebrionidae)
  • Pages - 277-287
  • M. SZCZEPANIK* and A. SZUMNY1
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  • View Abstract  The insecticidal activity of star anise (Illicum verumHook. F.) fruits extracts was determined against the lesser mealworm(Alphitobius diaperinus Panzer). In laboratory tests, 25.0, 12.5, 6.25 and 3.12 mg/ml-1extract concentrations as acetone solutions were added to diet of larvae and adults. The antifeedant effects of extract were investigated using choice and no-choice tests.The most sensitive stage was 7 days old larvae followed by 14 days old. Thirty days old larvae were highly tolerant to test extract. All applied doses caused the 100% mortality of younger larvae, however, only higher concentrations (25.0 and 12.5 mg/ml-1) were toxic to older larvae, whereas 25.0 mg/ml-1dose caused no mortality in adults. At lower doses, some older larvae developed into pupae and adults, but their body weight was lower than control. The extract was a very good feeding deterrent against larvae, but only in choice test. In the no choice test, the antifeedant effect was very weak.


April, 2011  Volume (27 - 2)
Allelochemical, Asplanchna brightwellii, Asplanchna girodi, Asplanchna sieboldii, Brachionus calyciflorus,kairomone, morphometry, phenotype, predator-prey.
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Effects of predator (Asplanchna) type and density on morphometric responses of Brachionus calyciflorus (Rotifera)
  • Pages - 289-299
  • JOSÉ LUIS GAMA-FLORES*, MARÍA ELENA HUIDOBRO-SALAS, S.S.S. SARMA1and S. NANDINI1
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  • View Abstract  Asplanchnais a predatory rotifer that induces changes in themorphology of its prey, the brachionid rotifer Brachionus calyciflorusthrough the release of an allelochemical (kairomone asplanchnin) into the medium. We quantified the morphological changes (lorica size and posterolateral spine length) of B. calyciflorus in response to presence of 3-con-phyletic predators(Asplanchna girodi, Asplanchna brightwelliiand Asplanchna sieboldii). All 3-predators induced significantly large lorica size and longer posterolateral spines in B. calyciflorus. However, magnitude of spine induction and body size changes in rotifer depended on the predator species and the duration of culture. The magnitude of induced morphological changes was in the decreasing order: A. sieboldii> A. brightwellii> A. girodi. Depending on the predator species, the body size and posterolateral spines of B. calyciflorusincreased from 4 to 24% and 50 to 115% than control, respectively. The predator type and density also affected the ratio of posterolateral spine length to body length. This ratio ranged from 0.15 to 0.23 in control, but was higher (0.24 to 0.48) in the presence of any test species of Asplanchna.


April, 2011  Volume (27 - 2)
Allelochemical, amphibian, fish (Ameca spendens), frog tadpole (Hylaplicata), larval axolotl (Ambystoma mexicanum), population dynamics, rotifer, zooplankton.
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Effects of kairomones from predatory vertebrates on the population growth of rotifer Plationus patulus(Müller)
  • Pages - 301-308
  • S. S. S. SARMA*, GISELA C. GÓMEZ-CABRAL, ADRIANA GARCÍA-ARROYO and S. NANDINI
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  • View Abstract  Aquatic vertebrate predators (fish and amphibians) influence the diversity and abundances of their prey such as zooplankton. However, predators also indirectly affect the prey populations by releasing chemical cues into the medium. Most studies have focused on the indirect effects of fish but very few on amphibians. In this work, the allelopathic effects of conditioned-medium fromfish (Ameca spendens), larval axolotl (Ambystoma mexicanum), and frog tadpoles (Hyla plicata) on the population growth of the common rotifer Plationus patuluswere evaluated. Compared to controls (free from allelochemicals), P. patulusgrown in the presence of vertebrate-conditioned-medium had higher peak population abundances. Within the vertebrate predators, the conditioned medium from axolotl and tadpole resulted in a 10-day longer phase of P. patulus. In controls and in fish-conditioned medium, therewas no lag phase. The rate of population growth of P. patulusvaried from 0.09 to 0.17 per day, depending on the treatment; the lowest being in fish-conditioned medium. These results have been interpreted in relation to the predator species.


April, 2011  Volume (27 - 2)
Bird cherry, bird cherry-oat aphid, Dactylis glomerata,migration, orchard grass, phenolic compounds, triticale,Prunus padus, Rhopalosiphum padi.
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Effects of host plant phenolics on spring migration of bird cherry-oat aphid (Rhopalosiphum padiL.)
  • Pages - 309-316
  • P. CZERNIEWICZ*, B. LESZCZYNSKI, G. CHRZANOWSKI, C. SEMPRUCH and H. SYTYKIEWICZ
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  • View Abstract  Differences in the quantity and quality of phenoliccompounds between the primary and secondary hosts of bird cherry-oat aphid(Rhopalosiphum padiL.) during its spring migration were studied. The aphid population developed on the primary host, the highest concentration of total phenolics was found in the mature leaves of bird cherry (Prunus padusL.) and R. padimigration onto secondary hosts was observed. At the same time the secondary hosts, orchard grass (Dactylis glomerataL.) and winter triticale (x TriticosecaleWittm.) contained over 30% less of the identified total phenolics. However, a more important factor was qualitative difference in the phenols composition among the host plants. In particular, chlorogenic acid, (+)-catechin, p-hydroxybenzoic acid and tannic acid occurred in much higher concentration within the bird cherry leaves. Siringic acid, p-coumaric acid and ferulic acid were slightly higher within tissues of the primary host. Other phenolics such as vanilic acid, caffeic acid, sinapic acid, salicylicacid, coumarin and o-coumaric acid were present in higher concentration within secondary hosts. Our results suggest that spring host alternation might be connected with variation in level and composition of the phenolics within host plants of the bird cherry-oat aphid.


July, 2011  Volume (28 - 1)
Acceptor cells, allelochemicals, Artemisia absinthium, biosensors, cell-donors, DNA, Equisetum arvense, fluorescence, germination, Hippeastrum hybridum, Matricaria reticuta, model systems, Philadelphus grandiflorus, pollen, Ruta graveolens, seeds, Trifolium pratense, Vallota speciosa, vegetative microspores
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Coloured allelochemicals in modelling of cell-cell allelopathic interactions
  • Pages - 12-Jan
  • V.V. ROSHCHINA*, V.A. YASHIN, A.V. YASHINA and M.V. GOLTYAEV
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  • View Abstract 

    Modelling of cell-cell interactions using microscopy is based on the observations of direct interactions of acceptor cells as biosensors (unicellular plant generative and vegetative microspores) with pigmented and fluorescing components of secretions released by the donor cells of allelopathic plant species. Pigmented secretions enriched in red anthocyanins (glucosides of pelargonidin from Hippeastrum hybridum petals), blue azulenes (synthetic azulene and azulene extracted from leaves of Artemisia absinthium) and yellow alkaloids (rutacridone from Ruta graveolens roots) serve as tool to study the mechanisms of cell-cell interactions. The compounds may stimulate or inhibit the germination of pollens, vegetative microspores and seeds. Test allelochemicals penetrate into the acceptor cells and get bound with DNA-containing organelles (nuclei and chloroplasts) that change the colour or fluorescence of cellular structures. Coloured allelochemicals were used as histochemical dyes to determine the cellular mechanisms during the allelopathic interactions.


July, 2011  Volume (28 - 1)
Allelopathy, a- amylase activity, ginseng,Panax ginseng, root exudates, seed germination.
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Allelopathic effects of ginseng root exudates on the seeds germination and growth of ginseng and American ginseng
  • Pages - 13-20
  • ZHANG, AI-HUA, LEI, FENG-JIE, GUO, ZHONG-XIAO and ZHANG, LIAN-XUE*
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  • View Abstract  We investigated the allelopathic effects of ginsengroot exudates on seed germination and biomass of ginseng and American ginseng. Ginseng was cultivated in a sterilized composite substrate. Root exudates were collected in-situand then successively extracted with water and methanol. Thetwo eluates were combined and partitioned with ethyl acetate. The water and ethylacetate extract were recovered and assayed. Root exudates exhibited a stronger allelopathic effect on ginseng than on American ginseng. Water-extract was more inhibitoryto seed germination and a-amylase activity of both ginseng and American ginseng. Root exudates inhibited the radical elongation of ginseng and American ginseng.The ethyl acetate extract proved more allelopathic. The inhibitory effects were concentration dependent. Ginseng root exudates had variable effects on the hypocotyl growth of ginseng and American ginseng. All extracts from roots of ginseng inhibited the fresh and dry weight of ginseng and American ginseng.


July, 2011  Volume (28 - 1)
Bottlegoured, Fusarium oxysporumf.sp. niveum, grafting, pumpkin, root exudates, root stock, sugars, watermelon.
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Sugars in watermelon root exudates and their effects on Fusarium oxysporumf. sp. niveum
  • Pages - 21-28
  • SHOUWEI LIU1, XINGANG ZHOU1, BO LIU, KAI PAN, SHUQIN LIU and FENGZHI WU*
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  • View Abstract  Sugar contents in root exudates from different watermelon varieties (susceptible or resistant to Fusarium oxysporumf.sp.niveum) and their grafted seedlings (with bottle gourd or pumpkin as rootstock) were measured. Effects of sugars on the growth and development of Fusarium oxysporumf.sp. niveumwere also evaluated in this experiment. Glucose, sucrose and total soluble sugar in root exudates of ungrafted resistant watermelon seedling were significantly lower than in ungrafted susceptible cultivar (P<0.05); but there was no significant difference in sugar contents of bottle gourd and pumpkin rootstocks. Glucose, sucrose and total soluble sugar contents in root exudates of grafted susceptible cultivar were significantly lower than in ungrafted susceptible cultivar (P<0.05). Resistant cultivar seedling grafted on pumpkin rootstock had higher glucose, sucrose and total soluble sugar contents compared with ungrafted watermelon seedling (P<0.05). Total soluble sugar content in resistant cultivars grafted on bottle gourd was significantly higher than in ungrafted watermelon seedlings (P<0.05). Glucose and sucrose promoted the growth and development of Fusarium oxysporumf.sp. niveum,and the stimulatory effect increased with sugar concentration. Our results suggested that the resistance of grafting and resistant cultivars may be due to the differences in sugar contents in root exudates.


July, 2011  Volume (28 - 1)
Actinomycetes, allelopathy, cinnamic acid, eggplants, fungi, grafted eggplants, growth, soil enzymes, soil microbes, vanillin.
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Allelopathic effects of cinnamic acid and vanillin on soil microbes, soil enzymes activities and growth of grafted eggplants
  • Pages - 29-40
  • S.L. CHEN, B.L. ZHOU*, S.S. LIN, X. LI, H.J. XI, Y.L. YIN, and X.L. YE
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  • View Abstract  The contents of cinnamic acid and vanillin in eggplants root exudates and continuous cropping soil were determined by HPLC method. The results showed that the two allelochemicals excreted from the roots remained in soil and gradually accumulated in soil with the growth stage and continuously planting for many years. The allelopathy of cinnamic acid and vanillin on soil microbes, soil enzyme activities and growth of grafted eggplants was studied. Application of both allelochemicals (cinnamic acid, vanillin) changed the microbes population of grafted eggplants and increased the bacteria (1.80-9.00%), actinomycetes (0.89-17.19%), but, fungi was decreased (0.32-11.15%) over ungrafted eggplants. Compared with ungrafted eggplants, grafted eggplants had higher activities of soil enzymes (catalase, polyphenoloxidase, urease, protease and saccharase). After application of cinnamic acid and vanillin, the protease activity was enhanced markedly from 0.40 to 17.44%. The grafting affected the development of microbes and changed their relations between the bacteria, actinomycetes and fungi and made eggplants resistant to allelochemicals stress. The grafted eggplants grew taller, had larger stem diameter, increased the leaf chlorophyll content (3.90-16.0%), reduced the root relative conductivity and decreased the MDA content, while, the root SOD activity was enhanced over the ungrafted eggplants under cinnamic acid and vanillin stress. It may be possible that mechanism to resist allelochemicals stress in grafted eggplants improved the soil biological environment.


July, 2011  Volume (28 - 1)
Bioassay, fennel, Foeniculum vulgare, germination, interference, native, non-native invasive plant.
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Effects of fennel (Foeniculum vulgareL.) interference on germination of introduced and native plant species
  • Pages - 41-51
  • WESLEY I. COLVIN III* and STEPHEN R. GLIESSMAN2
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  • View Abstract  Allelopathy was proposed as one mechanism that allows introduced species to become invasive. With this examination being the first of a three-part series, we evaluated this concept for the invasive fennel plant (Foeniculum vulgare) whose allelopathic potential is recognized. Since the late 1980s, fennel has invaded grassland and soft chaparral vegetation communitieson Santa Cruz Island in Channel Islands National Park. Using a rapid bioassay technique, we evaluated the germination response of forb and grass functional groups from different centres of origin. The response of 34 California native and introduced Mediterranean species to water soluble fennel leaf leachate was determined in the laboratory between April 2005 and August 2006. In general, germination of native species was significantly inhibited at fennel leachate concentrations above 2.0%. For introduced species, there was no significant effect on germination with most speciesable to germinate in leachate concentrations of 5.0%. Native species were negatively impacted at the most critical stage in their development, whereas introduced species were able to germinate even at the highest treatment concentration of fennel leachate used in bioassay.


July, 2011  Volume (28 - 1)
Allelopathy, Cynodon dactylon, Digitaria sanguinalis, Festuca arundinacea, Tephrosia vogelii, weed control
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Allelopathic potential of Tephrosia vogelii Hook. f.: Laboratory and field evaluation
  • Pages - 53-61
  • RUILONG WANG1,2, XINYU YANG1,2, YUANYUAN SONG 1,2, MOXI ZHANG1,2, LINHU1,2, YIJUAN SU1,2 and RENSEN ZENG1,2*
  • View 
  • View Abstract  Tephrosia vogelii Hook. f. is legume plant used to produce insecticidal rotenoid and numerous ethno-medicines. However, little is known about its allelopathic effects. To find its allelopathic potential in weed control, bioassays were conducted with aqueous leachates of its fresh leaves, leaf volatiles and leaf litter leachates against the seed germination and growth of 3 weed species (Festuca arundinaceaSchreb., Cynodon dactylon(L.)Pers. andDigitaria sanguinalis (L.)Scop.). Field experiment was done using dry leaves ofT. vogeliias mulches on soil surface to evaluate their allelopathic potential on corn (Zea maysL.) and weeds. Bioassay showed that the aqueous leachates from fresh leaves at =0.05 g/mL and the volatiles of T. vogeliiat =0.03 g/cm3 significantly inhibited the seed germination and seedling growth of all three tested weed plants. Field experiment showed that T. vogeliimulching increased the biomass of corn by 14.0%, but also decreased the total biomass of weeds (15.8% at 200 g/m2). Both laboratory and field experiments showed that T. vogeliihad allelopathic effects on some weeds, suggestingthe possibility of using its allelopathic potential, insecticidal activity and nitrogen fixation of T. vogeliifor sustainable pest management and organic fertilizer.


July, 2011  Volume (28 - 1)
Allelopathic potential; germination index; growth; inhibitory response; Inula graveolens;plant parts.
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Allelopathic potential of Inula graveolenson crops and weeds
  • Pages - 63-76
  • F. OMEZZINE1, A. LADHARI1, A. RINEZ1 and R. HAOUALA1
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  • View Abstract  In Lab. bioassay, the effects of aqueous extracts (10, 20, 30 and 40 g/L) and organic extracts (hexane, chloroform and methanol at 3 and 6 mg/mL) of roots, shoots (stems + leaves) and flowers of Inula graveolens L. were tested on the seed germination and seedling growth of Lactuca sativaL., Raphanus sativusL., Peganum harmalaL. and Silybum marianumL. While in pot culture, powder of shoots and flowers at 1.25 and 2.5 g/100g was incorporated in soil to evaluate its allelopathic effect on test spp. PEG 4000 solutions with similarosmotic potentials to aqueous extracts at 40 g/L, neither affected the germination index nor growth of target species. Root extracts did not influence the germination index but shoot and flower extracts delayed and reduced the germination in all target seeds. Root extract at 10 g/L stimulated the seedlings growth of lettuce, radish and peganum, but was harmful to thistle. The organic extracts of shoot and flower at 6 mg/mL significantly inhibited the seedling growth especially in chloroform fractions.Soil incorporation of residues significantly decreased the root and shoot length of target species. Application of shoot and flower aqueous extracts in soil decreasedthe seedlings length, however, flower extract was more inhibitory than shoot.


July, 2011  Volume (28 - 1)
Allelopathy, Baccharis dracunculifolia, essential oils, Lactuca sativa, limonene,Lolium multiflorum, monoterpenes, phenolics, phytotoxicity, pinene, volatiles.
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Assessment of allelopathic properties of Baccharis dracunculifoliaDC in laboratory and field conditions
  • Pages - 77-85
  • F. IBÁÑEZ1*and R. ZOPPOLO
  • View 
  • View Abstract  In plantations of B. dracunculifolia, a noticeable decrease in diversity and development of monocots species was observed. Hence, phytotoxic studies were done to determine the in vitrotoxicity of essential oils of B. dracunculifoliaon monocot(Lolium multiflorum) and dicot (Lactuca sativa).The essential oil at concentration of 1000 mg/L drastically decreased the hypocotyl growth of L. multiflorum(90%) and L. sativa(60%). The analysis of essential oil by gas chromatography showed a high percentage of compounds with phytotoxic effects, such as limonene, aand ß-pinene. The field experiments showed that the inhibition under B. dracunculifoliawas not due to the effect of shading nor to nutrient competition. The reduction in germination of L. multiflorumunder B. dracunculifoliawas > 90%. In the soil under the plantation, a high concentration of phenolics was measured (15mg/100g of soil). These results indicate that allelopathic activity of B. dracunculifoliamay be explained through a combination of phytotoxic effects (emission of volatile compounds and the accumulation of phenolics in the soil profile).


July, 2011  Volume (28 - 1)
Allelopathy, annual ryegrass, barley grass,Eucalyptus dundasii, Hordeum spp., Lolium rigidum,weeds.
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Allelopathic effects of Eucalyptus dundasiion germination and growth of ryegrass and barley grass
  • Pages - 87-94
  • HANWEN WU, JINBIAO ZHANG*1, REX STANTON2, MIN AN3, DE LI LIU and DEIRDRE LEMERLE2
  • View 
  • View Abstract  To overcome the rapid development of herbicide resistance in weeds, there is an increasing demand for alternative weed control. There is limited understory vegetation within the dripline of Eucalyptus dundasiiMaiden in fields.We studied the allelopathic potential of E. dundasiion two important Australian weeds species: annual ryegrass (Lolium rigidumGaudin) and barley grass (Hordeum glaucum Steud.). Distillation of eucalyptus leaves yielded three bioactive fractions: essential oil fraction and the aqueous fractions A and B. These 3- fractions inhibited the germination and seedling growth of annual ryegrass and barley grass. Essential oils proved most inhibitory to germination and shoot growth of both test weeds, followed by the aqueous fraction B and fraction A. Both weeds had similar responses, when exposed to essential oils. However, the germination and seedling growth of barley grass were more sensitive than annual ryegrass to aqueous fraction A and the germination of annual ryegrass was more sensitive than barley grass when exposed to fraction B. The phytotoxicity was concentration-dependent. The phytotoxic effects identified in the aqueous fraction A indicated that significant rainfall could be washed off some of compounds of essential oils into the ground to provide natural chemical defense against understory vegetation. Further study on other Eucalyptus species, followed by the identification of bioactive compounds, might provide chemical leads for the development of new herbicides with new modes of action.


July, 2011  Volume (28 - 1)
Activity-guided fractionation, Allelochemicals, Antialgal compounds, Macrophyte, Potamogeton maackianus, Selenastrum capricornutum
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Isolation and identification of antialgal compounds from Potamogeton maackianusby activity-guided fractionation
  • Pages - 95-104
  • S.H. ZHANG, S.P. CHENG2, P.S. SUN, H.Q. WANG1and Z.B. WU1*
  • View 
  • View Abstract  Potamogeton maackianusis major submerged species in China. Its antialgal allelopathic activities have been demonstrated, butits antialgal compounds are not fully known. To investigate the antialgal chemicalsof P. maackianus, EtOH extracts of this macrophyte were further isolated by activity-guided fractionations. The antialgal bioassays of fractions were tested on algal specie, Selenastrum capricornutum. Through column chromatography (silica gel chromatography, ODS C18 P-HPLC, Sephadex LH-20) and preparative thin layer chromatography (P-TLC), six antialgal compounds (PK1-6) were isolated and their structures were determined by mass spectrum (EI-MS) and nuclear magnetic resonance (NMR) spectroscopy (1H, 13C, 13C-DEPT, H-H COSY, HSQC and HMBC). PK1-PK6 wereidentified as stigmasterol (PK1), 4-hydroxybenzoic acid (PK2), 6-hydroxy-a-ionone (PK3), (E)-4-(4-hydroxy-3,3,8-trimethyl-9- -oxa-bicycle[6.1.0]nonan-4-yl) but-3-en-2-one (PK4), 1H-indole-3-carbaldehyde (PK5) and lignan (+)-pinoresinol (PK6), respectively. All six compounds were isolated for the first time from P. maackianus, while, PK3 was isolated from natural plants for first time and PK4 is a new compound. The results of bioassay showed that algal growth were obviously inhibited by the six isolated compounds at 20 mg L-1, and antialgal activities followed the order: PK3,PK4 > PK6 > PK5 > PK2 > PK1. The PK3 and PK4 completely inhibited the growth of S. capricornutum but stigmasterol was less inhibitory (30.4%) to PK1.


July, 2011  Volume (28 - 1)
Alfalfa, coumarin, enzymes, Glutamate dehydrogenase (GDH), Glutamine synthase (GS), Nitrate reductase (NR), nitrogen metabolism, photosynthetic pigments, plant growth, soluble proteins
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Effects of coumarin application on plant growth and nitrogen metabolism in leaves of Medicago sativa
  • Pages - 105-114
  • YINPING CHEN1, LEI ZHANG3 and JINCHUANG WANG1,2,*
  • View 
  • View Abstract  The effects of coumarin application were investigated on growth, photosynthetic pigments, concentration of nitrate (NO3-), ammonium (NH4+), soluble proteins and Enzymes [nitrate reductase (NR), glutamine synthase (GS) and glutamate dehydrogenase (GDH)] activities in leaves of alfalfa (Medicago sativa). Five-day-old alfalfa seedlings were exposed to 0, 25 µM, 50 µM, 0.1 mM and 1 mM concentrations of coumarin. Up to 50 µM, coumarin did not affect the concentrations of N forms, key enzymes of nitrogen metabolism and plant growth. Above 0.1 mM concentrations, coumarin reduced the shoot and root fresh biomass, photosynthetic pigments, nitrate (NO3-), soluble proteins and NR activities and yet increased the ammonium (NH4+) concentration and GDH activities. Moreover, only 1 mM coumarin significantly reduced (32.64%) the activity of GS. Thus, it was concluded that coumarin at higher concentration adversely affects the plant growth and the key enzymes of nitrogen metabolism in alfalfa.


July, 2011  Volume (28 - 1)
Abscisic acid, cytokinins, indole-3-acetic acid, lichen metabolites, phytohormones, tomato, usnic acid
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Allelopathic effects of (+)-usnic acid on some phytohormone concentrations in tomato plants
  • Pages - 115-122
  • J. BIALCZYK, E. LATKOWSKA* and Z. LECHOWSKI
  • View 
  • View Abstract  Usnic acid (UA), the main phenolic secondary metabolite in some lichens, affected the phytohormone concentrations in tomato organs. Long-term cultivation of tomato plants in Hoagland media supplemented with 30 µM (+)-UA reduced the phytohormone concentrations than control levels in leaves and roots. The reduction in indole-3-acetic acid (IAA), in leaves and roots was61% and 66%; 62% and 36% for cytokinins (CKs), and 40% and 71% for abscisic acid(ABA) respectively. This may due to blocking or changing the direction of metabolic transformation of precursor(s) and/or increased activity of enzyme(s) engaged in catabolic pathways. UA also reduced the transport of phytohormones between the main site of their synthesis and other organs. This is evident from the changes in the root/leaf ratios of phytohormone molecular concentrations, which for IAA decreased from 3.0 in the control to 2.6 in plants grown in media with (+)-UA and for ABA from 0.35 to 0.16. The root /leaf ratio of cytokinins molar concentrations increased from 1.5 in control to 2.5 in plants cultivated in media with additional 30 µM (+)-UA supplement.


July, 2011  Volume (28 - 1)
Abelmoschus esculentus (lady’s finger), Capsicum annum (chilli), germination, Glycine max (soybean), inhibition, leaf extract, Oryza sativa (rice), root length, shoot length, stimulation, Zea mays (maize).
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Effects of leaf extracts of common home garden trees on food crops
  • Pages - 123-134
  • U.K. SAHOO*, K. VANLALHRIATPUIA, K. UPADHYAYA and S. ROY
  • View 
  • View Abstract  In Lab. bioassays and pot culture, the effects of aqueous leaf extract of 5 home garden trees [Artocarpus heterophyllus L.,Mangifera indica L.,Areca catechu L., Citrus indica Tanaka and Tamarindus indicaL.] were studied on the germination, shoot length and root length of 5 food crops [Capsicum annum L. (Chilli), Glycine max (L.) Merr. (Soybean), Zea mays L. (Maize), Oryza sativa L. (Rice), and Abelmoschus esculentus (L.) Moench (Lady’s finger)]. Air-dried fresh leaves of selected trees were crushed and soaked in water, diluted to prepare extracts concentrations for bioassay and pot culture. In bioassays, the inhibitory effects of leaf extracts on germination were upto 85.2% over control in chilli. Shoot length was most adversely affected in lady’s finger, while theroot elongation was suppressed in paddy. In pot culture, maximum inhibition in seed germination was exerted by T.indica(37%) followed by C. indica (19.5%),M. indica (13.1%),A. heterophyllus and A. catechu (12.4% each) of all the test crops, germination andseedling vigour was severely decreased in lady’s finger. Most of the food crops, except paddy were inhibited by Tamarindusleaf extract and hence, are incompatible. Soybean was also sensitive to Artocarpusextracts, while germination and growth of lady’s finger was inhibited by all tree species except Artocarpus. Paddy was resistant to allelopathic effects of all tree species.


October, 2011  Volume (28 - 2)
Activated carbon, autotoxicity, bioassay, Lycopersicon esculentum, physiological characteristics, tomato
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Autotoxicity effects of soils continuously cropped with tomato
  • Pages - 135-144
  • SUN YAN-YAN1, JIANG GUI-YING, WEI XIAO-CHUN2and LIU JIAN-GUO*
  • View 
  • View Abstract  A pot experiment was done to determine the effects of continuous cropping and application of activated charcoal in soil on the growth, antioxidant enzyme activity and physiological parameters of photosynthesis in tomato (Lycopersicon esculentum Miller). The yield and biomass of tomato were significantly inhibited with the continuous cropping. The 2, 3 and 4-years of continuous cropping inhibitory the yield and biomass of tomato by 5.34%, 21.5%, 29.3% and 11.7%, 16.3%, 38.8%. The increasing duration of continuous cropping, decreased the activity of superoxide dismutase (SOD), root vigour and chlorophyll content in tomato plants. However, the peroxidase (POD) activity declined after increasing, but malonyldialdehyde (MDA) content was increased. Application of activated charcoal in soil greatly improved the physiological characteristics (SOD activity and chlorophyll content), but MDA content was decreased in tomato plants grown in soil mixed with activated charcoal than in soil without activated charcoal. Besides, the net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) decreased with prolonged cropping time (4-years) to 58.7%, 45.8% and 55.1% than control (1-year), respectively. The addition of activated charcoal to soil, increased the Pn, Gsand Tr than their control (no activated charcoal), respectively by 236.9%, 106.6%and 161.9%. The results suggested that adding of activated charcoal to soilchanged the autotoxic effects of tomato, the antioxidant enzymes activities and decreased the physiological parameters.


October, 2011  Volume (28 - 2)
Autotoxicity, early seedling growth, GCMS, Panax ginseng, soil extract.
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Autotoxicity of Panax ginseng rhizosphere and non-rhizosphere soil extracts on early seedlings growth and identification of chemicals
  • Pages - 145-154
  • Y. LI,X. F. HUANG and W.L. DING*
  • View 
  • View Abstract  Laboratory experiments were conducted to study the allelopathy of Panax ginsenggrowing soil extracts on the growth of its own seedlings. Soil samples were extracted with methanol. P. ginsengseeds were incubated on water-soaked filter paper in Petri dishes containing 6-concentrations (50,100,150,200,250,300 µl per petri dish) of extracts. Each treatment was replicated thrice. After incubation at 20oC in darkness for 15 days, radicle and shoot length of ginseng seedlings were measured to determine the effects of soil extracts. The methanol extract from P. ginsengrhizosphere soil inhibited the growth of P. ginsengseedlings more than extracts from non-rhizosphere soils. Furthermore, chemicals in each soil extractswere analyzed by GC-MS, and more than 30 chemicals were identified.


October, 2011  Volume (28 - 2)
Autointoxication, autotoxins, Camellia sinensisL., old tea garden,phenolic compounds, regeneration problem, root exudates, tea.
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Autointoxication of tea (Camellia sinensis) and identification of its autotoxins
  • Pages - 155-165
  • PAN RONG CAO*,CHUN YAN LIU and DAN LI
  • View 
  • View Abstract  The regeneration in old tea gardens is a big problem. To understand its mechanism, the autointoxication of tea was investigated and the phenolic acids and total phenolics in the soil extracts and root exudates were analyzed. The aqueous extracts from different plant parts significantly inhibited the seed germination, root and shoot growth of tea seedlings. The seed germinationand seedling growth of tea were also inhibited by the aqueous extracts of rhizosphere soil of tea trees with different ages. the inhibition increased with the growing years. Nine phenolic acids (ferulic, cinnamic, vanillic, p-coumaric, benzoic, p-hydroxybenzoic, caffeic, chlorogenic and gallic) were identified in soil extracts. But the benzoic acids andp-hydroxybenzoic acids were not detected in the root exudates. The soil extraction contained bound or free forms of ferulic, cinnamic, vanillic, p-coumaric, caffeic, chlorogenic and gallic acids. Their concentrations varied with tea tree age. The relative contents of total phenolic acids in the soil extraction increased with the age of tea trees. These results suggested that the phenolic acids accumulate in old tea garden might result in tea autotoxicity and the problem of continuous cropping.


October, 2011  Volume (28 - 2)
Allelopathy, rice extracts, QTL, integrated weed management, cultivar screening
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Allelopathic potentials of rice (Oryza sativaL.) cultivars leaves, straw and hull extracts on seed germinationof barnyardgrass (Echinochloa crus-galliL.)
  • Pages - 167-178
  • H. MENNAN*, E. KAYA-ALTOP, M. NGOUAJIO1, M. SAHIN2 and D. ISIK3
  • View 
  • View Abstract  High crop competitive ability is an important component of integrated weed management. Allelopathic compounds released byrice (Oryza sativaL.) could help enhance its competitive ability and improve weed management. This study aimed to screen rice genotypes for allelopathic activity and to identify the potential parental lines for QTL analysis. Therefore, a total of 41 cultivars from germplasm collections in Turkey were evaluated for their allelopathic effects. Significant differences were found among the rice cultivars in their ability to reduce barnyardgrass (E. crus-galli) root growth and root dry weight accumulation. Root length inhibition ranged from 0.7% to 38.8%, respectively. The ‘Marateli’ and ‘Koral’ cultivars inhibited the root length by 38.8% and 31.2%, respectively. However, ‘Arko’, ‘Edirne’, ‘Kirkpinar’ and ‘Sumnu’ stimulated the root length and dry weight than control. Rice tissue extracts had variability to inhibit the E. crus-galligermination, the ‘Marateli’ leaf extracts were most inhibitory to germination. The ‘Kiziltan’, ‘Koral’ and ‘Marateli’ were identified for breeding of rice cultivars with higher allelopathic potential. Development of rice cultivar with proven allopathiccharacteristics could provide an environmentally friendly and low-cost approach for E. crus-gallicontrol.


October, 2011  Volume (28 - 2)
Allelochemicals, Calotropis gigantea (R.Br.), cyclopropene fatty acid, Datura metel (L.), growth inhibitors, herbicide,Parthenium hysterophorus (L.), Sterculia foetida(L.), Tridax procumbens (L.), weed control.
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Allelopathic effects of Sterculia foetida(L.) against four major weeds
  • Pages - 179-188
  • PATHIPATI USHA RANI*1, PALA RAJASEKHARREDDY1and K. NAGAIAH2
  • View 
  • View Abstract  Isolation and identification of allelopathic substances from plants is an important step to study allelopathy. The herbicidalpotential of crude, column fractions and an isolated pure compound of Sterculia foetida(L.) seeds were assessed against the 4-Indian major weeds: Calotropis gigantea (R.Br.),Parthenium hysterophorus (L.),Datura metel (L.) and Tridax procumbens (L.). The potent herbicidal constituent of S. foetidaseeds was characterized as a cyclopropene fatty acid structurally elucidated as (2n-octylcycloprop-1-enyl)-octanoic acid (I) by spectroscopic analysis. The foliar application of S. foetidaseed derived pure compound acted as a contact herbicide, causing initial chlorosis and necrosis followed by defoliation. The herbicidal potential of the isolated compounds were examined against seed germination, shoot and root length of the weed plants. The S. foetida seed derived crude, column fractions and isolated pure compound at 150, 75 and 10 mg/L, significantly inhibited the seed germination, shootand root length respectively.


October, 2011  Volume (28 - 2)
Allelopathy, aqueous extracts, Bothriochloa, inhibition, Poaceae, root growth, seed germination, shoot growth
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Allelopathic potential of South American Bothriochloa species (Poaceae: Andropogoneae)
  • Pages - 189-200
  • L. R. SCRIVANTI1*, A. M. ANTON and JULIO A. ZYGADLO
  • View 
  • View Abstract  In laboratory bioassays the aqueous extracts from different plant parts of six Bothriochloa species (B. barbinodis, B. edwardsiana, B. perforata, B. saccharoides,. var. saccharoidesand B. springfieldii) inhibited the seed germination and root and shoot growth of lettuce (Lactuca sativa L.), maize (Zea mays L.), wintergreen paspalum (Paspalum guenoarum Arechav.) and lovegrass [Eragrostis curvula (Schrad.) Nees)] test species. Aqueous extracts were more inhibitory to shoot and root elongation than to seed germination. Significant inhibition in shoot length at all concentrations indicated the phytotoxic activity ofextracts. The toxicity enhanced with increasing aqueous extract concentrations. Perhaps these extracts may contain allelochemicals, which interferes with seed germination and seedling growth of plants. Consequently, the study of these chemical interactions might be useful to develop new classes of environmentally safe herbicides.


October, 2011  Volume (28 - 2)
Aedes aegypti, allelopathic activity, bioautography, Cladosporium sphaerospermum,fungicidal, germination, Gomphrena elegans, insecticidal activity, Lactuca sativa, seedling growth, Sitophilus zeamais,wheat.
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Biological activity of Gomphrena elegansMart. Var. Elegans(Amaranthaceae)
  • Pages - 201-211
  • T. S. MAHMOUD1, M. R. MARQUES1, C. B. LEITE1, M. M. ANTONIO1, A. S. MAHMOUD1, A. P. DE SOUZA1, D. P. DE LIMA1and J. E. DE OLIVEIRA
  • View 
  • View Abstract  In this study, we evaluated the allelopathic, insecticidal and fungicidal activities of 16- extracts (different polarities) of Gomphrena elegansMart. (Amaranthaceae). The potential allelopathic of extracts of G. elegansobtained from leaves and stems were most inhibitory to the germination and seedlings growth L. sativa, in general, the extracts stimulated the growth ofseedlings. The insecticidal activity of extracts were evaluated using ten g of wheat sprayed with 1 mL of each extract at 10% (w/v), the grains were placed in containers with 20 Sitophilus zeamais adults and the assessments were made at 5 and 10 days. The most active were the hexane, chloroform and aqueous extracts; however, they showed no insecticidal activity against Aedes aegypti. All extracts were evaluated for antifungal activity against the plant pathogenic fungusCladosporium sphaerospermum using the direct bioautography. The most active was the aqueous extract of adventitious roots.


October, 2011  Volume (28 - 2)
Abutilon theophrasti, Amaranthus retroflexus, barnyardgrass, Common nandina, cucumber, Cucumis sativus, Echinochloa crusgalli,Lactuca sativa, lettuce, Nandina domestica., p-hydroxybenzaldehyde, phytotoxic activity, redroot amaranth, Triticum aestivum, wheat.
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p-hydroxybenzaldehyde, a growth inhibitory chemical extracted from common nandina (Nandina domesticaThunb.) leaf
  • Pages - 213-224
  • J. HAN, Y. J. AHN1 and X.Y.LUO*
  • View 
  • View Abstract  Phytotoxicity of active substances in common nandina (Nandina domestica Thunb.) was investigated. Bioassays were conducted using several weeds [(redroot amaranth (Amaranthus retroflexusL.), Abutilon theophrastiMedic. and barnyardgrass (Echinochloa crusgalli(L.) Beauv.)] and crops [(lettuce (Lactuca sativaL.), cucumber (Cucumis sativusL.) and wheat (Triticum aestivumL.)] as receptor plants by the method of grinded plant tissue powder mixed with agar (PPA). The inhibitory effects of leaf powders of common nandina at 10 g·L-1concentration on the seedling growth of lettuce were more pronounced than other plant parts. According to the EC50values of common nandina leaf powder on the different receptor plants, dicotyledon plants of redroot amaranth, lettuce, A.theophrastiand cucumber showed higher susceptibility than monocotyledon plants of wheat and barnyardgrass, with redroot amaranth showing the highest susceptibility. The common nandina leaves may possess phytotoxic potential and active substance. The methanol extract of its leaves was purified and one growth inhibitory substance was isolated and identified as p-hydroxybenzaldehyde by its 1H-NMR, 13C-NMR and EI-MS spectral data. The seedling growth of lettuce and redroot amaranth were strongly inhibited at 0.125 g·L-1and the roots died at 0.500 g·L-1concentrations. It suggested that p-hydroxybenzaldehyde may contribute to the phytotoxicity of common nandina.


October, 2011  Volume (28 - 2)
Allelochemicals, cinnamic acid, enzymes, ferulic acid, p-hydroxybenzoic acid, microorganisms, nitrogen, phenolic acids, phosphorus, potassium, salicylic acid, vanillic acid.
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Impact of applied phenolic acids on the microbes, enzymes and available nutrients in paddy soils
  • Pages - 225-236
  • R. Y. LIN1, H. B. WANG1, X. K. GUO1, C. Y. YE1, H. B. HE1, Y. ZHOU1 and W. X. LIN1*
  • View 
  • View Abstract  Phenolic acids are important compounds in plant allelopathy, hence the effects of 5-applied phenolic acids (p-hydroxybenzoic acid, ferulic acid, salicylic acid, vanillic acid, and cinnamic acid), were determined on the microbial community, enzyme activities and available nutrients in paddy soil. The application of phenolic acids significantly enhanced the soil microbial biomass carbon (MBC), soil microbial respiration rate (MBR), soil microbial populations,improved the soil enzyme activities and proved beneficial to the available nutrients (nitrogen, phosphorus and potassium) in soil. Three days after application ofphenolic acids in soil they increased the soil MBC by 23.4% to 110.1% and MBR by 37.6% to86.1% over the control, but these declined later on. The population of bacteriawas increased by 43.3% to 255.0%, 11.1% to 44.4%, for fungi, and 87.8% to 226.8 % foractinomycetes over the control. The activity of urease was 56.6% to 163.3%, protease activity was 75.0% to 162.5%, and sucrase activity was 109.3% to 220.9% higher than control. The available nitrogen, phosphorus and potassium in the soils were significantly increased by 99.0% to 168.5%, 134.6% to 241.7% and 11.5% to 12.9%, respectively. The promoting effects of applied phenolic acids followed the order: p-hydroxybenzoic acid > ferulic acid > vanillic acid > salicylic acid > cinnamic acid. Furthermore, all the bacteria, available phosphorus and potassium were significantly positively correlated with the five applied phenolic acids. While the actinomycetes, urease and nitrogen had significantly positive correlation with p-hydroxybenzoic acid; the fungi, actinomycetes and protease had significant correlation with ferulic acid, the urease, protease, sucrase and available nitrogen were significantly positively correlated with salicylic acid; the actinomycetes, urease, proteaseand nitrogen had significantly positive correlation with vanillic acid. The protease and sucrase had significantly positive correlation with cinnamic acid. It suggested that phenolic acids are useful carbon resources to establish soil microbial community, enhance the activities of soil enzyme, and accelerate the nutrients cycling in soil.


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