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Sample records for lefpa barnyardgrass echinochloa

  1. The Effects of Seed Burial and Flooding Depths on Emergence and Seedling Growth of Watergrass (Echinochloa oryzoides and Barnyardgrass (E. crus-galli

    Directory of Open Access Journals (Sweden)

    E Mohammadvand

    2013-04-01

    Full Text Available In order to determine the effects of seed burial and flooding depths on the emergence and seedling growth of watergrass (Echinochloa oryzoides and barnyardgrass (E. crus-galli, this experiment was conducted in a covered free air condition, at the Rice Research Institute of Iran, Rasht in summer of 2009. The treatments included four seeding depths (0.1 (seeds were mixed with the top soil, 2, 4 and 6 cm, and four flooding depths (0.1 (saturated soil with no standing water, 3, 6, and 9 cm arranged as a factorial arrangement in a randomized complete block design with three replications. After 28 days, number of emergent seedlings, weed seedlings height, root and shoot fresh weight, leaf and root area were measured, and emergence percentage and root/shoot ratio were calculated. Since no germination of seeds was observed at the 6 cm sowing depth, this treatment wasn’t presented in results. Measured or calculated variable per unit was significantly different between two species and between various levels of seed burial and flooding depths. These variables also influenced by the interactions of the mentioned factors with an exception of emergence percentage. Emergence percentage and growth characteristics except for plant height were higher in E. oryzoides than E. crus-galli when weed seeds were located in the depth of 0.1 centimeter. In seeds located in the depth of 2 centimeters, all variables were higher in E. oryzoides than E. crus-galli. In both species, the higher values for mentioned variables was observed in the saturated condition of soil, when weed seeds were located at the depth of 0.1 centimeter and reduced with increasing flooding and seed burial depth. Results indicated that flooding condition with adequate height caused major limiting effects on emergence, establishment and growth of two Echinochloa species, especially when the seeds were deeply buried; but at decreased height specially saturated soils, emergence and growth of E

  2. Seed germination and seedling emergence of velvetleaf (Abutilon theophrasti and Barnyardgrass (Echinochloa crus-galli Germinação de sementes e emergência de plântulas de Abutilon theophrasti e Echinochloa crus-galli

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    A. Sadeghloo

    2013-06-01

    Full Text Available Abutilon theophrasti and Barnyardgrass (Echinochloa crus-galli are major weeds that affect cropping systems worldwide. Laboratory and greenhouse studies were conducted to determine the effects of temperature, pH, water and salinity stress, and planting depth on seed germination and seedling emergence of Velvetleaf and Barnyardgrass. For Velvetleaf, the base, optimum and ceiling germination temperatures were estimated as 5, 35 and 48 ºC, respectively. Seed germination was sensitive to drought stress and completely inhibited by a potential of -0.6 MPa, but it was tolerant to salinity. Salinity stress up to 45 mM had no effect on the germination of Velvetleaf, but germination decreased with increasing salt concentration. Drought and salinity levels for 50% inhibition of maximum germination were -0.3 MPa and 110 mM, respectively. Seed germination of Velvetleaf was tolerant to a wide range of pH levels. For Barnyardgrass, the base, optimum and ceiling germination temperatures were estimated as 5, 38 and 45 ºC, respectively. Seed germination was tolerant to drought stress and completely inhibited by a potential of -1.0 MPa. Salinity stress up to 250 mM had no effect on seed germination. Drought and salinity levels for 50% inhibition of maximum germination were -0.5 MPa and 307 mM, respectively. A high percentage of seed germination was observed at pH=5 and decreased to 61.5% at acidic medium (pH 4 and to 11% at alkaline medium (pH 9. Maximum seedling emergence of Velvetleaf and Barnyardgrass occurred when the seeds were placed on the surface of the soil or at a depth of 1 cm.Abutilon theophrastie Echinochloa crus-galli são as principais plantas daninhas que afetam os sistemas de cultivo em muitas partes do mundo. Estudos em laboratório e em casa de vegetação foram conduzidos para determinar os efeitos da temperatura, pH da água e estresse salino e da profundidade de semeadura na germinação e na emergência das plântulas de A. theophrasti e E

  3. Mechanical and Chemical Integrated Management of Barnyardgrass (Echinochloa crus–galli (L. Beauv and Smallflower umbrella (Cyperus diformis L. in Rice

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    S. Mahzari

    2013-06-01

    Full Text Available To investigate the effects of integrated mechanical and chemical weed management on barnyardgrass, smallflower umbrella and some rice agronomic characteristics an experiment was conducted in Rice Research Institute of Iran, Deputy of Mazandaran (Amol during 2010 growing season. The experiment was performed in spilt-plot based Randomized Complete Block Design with three replications. Main plots consisted of three levels control (measures without weed control, one time and two times applications of cono-weeder and sub plots were seven herbicide applications (application of bentazon, bensulfuron-methyl, oxadiazone, butachlor, thiobencarb, hand weeding and control. The results indicated that the interaction of two mentioned factors did not have any significant effects on barnyardgrass and smallflower umbrella densities, but it had significant effect on weed total dry matter. The best method used to reduce weed total dry matter was hand weeding and two times application of cono-weeder without using herbicides. The highest grain yield was harvested in plots which treated by two times application of cono-weeder with or without herbicides applications, and hand weed control treatment.

  4. Improvement of barnyardgrass potential biocontrol fungus by NTG inducing and 60Co γ-ray irradiation

    International Nuclear Information System (INIS)

    Huang Shiwen; Yu Liuqing; Duan Guifang; Zhao Hang; Luo Kuan

    2004-01-01

    Helminthosporium gramineum Rabenh f.sp. echinochloae (HGE), the Barnyardgrass (Echinochloa spp.) potential biocontrol fungus was induced by nitrosoguanidine (NTG, C 2 H 5 N 5 O 3 ). The high yield of conidia production of inducing strain I 262 was obtained. Conidia production of I 262 increased 52.6% compared with its original fungus HGE. The experiments of nuclear irradiation were conducted by using I 262 as starting strain. I 262 was irradiated for 57 minutes by 60 Co γ-rays at the dose of 650 Gy. Among selecting mutants, there are 7.75% strains' conidia production higher than that of I 262 . Among them, conidia production of mutants F II 121 , F II 116 and F II 140 increased 54.4%, 51.5% and 41.7% compared with that of I 262 , respectively. Conidia yield of mutants F II 121 and F II 116 were doubled compared with their original fungus HGE when using chemical in combine with physical technologies to treat the barnyardgrass' pathogen. The pathogenicity and control efficacy to barnyardgrass of high yield conidia production mutants were as the same as their original fungus HGE. (authors)

  5. [Influence of weeds in Echinochloa on growth and yield of rice].

    Science.gov (United States)

    Zhang, Zi-Chang; Li, Yong-Feng; Zhang, Bin; Yang, Xia

    2014-11-01

    In order to investigate effects of different barnyardgrass species on growth and yiled of rice, two rice cultivars, Xinliangyou 6 hao (an indica hybrid cultivar) and Nanjing 46 (a japonica cultivar), were co-cultured with four barnyardgrass species grown at a density of six plants · m(-2) from 10 days after transplanting to maturity. The treatments were designed as follow: weed free (control), rice with Echinochloa crusgalli var. mitis (T1), rice with E. crusgalli (T2), rice with E. crusgali var. zelayensis (T3), and rice with E. colonum (T4). The result showed that barnyardgrass-induced reductions in grain yield of rice were obviously different among the four treatments. T1, T2 and T3 treatments reduced the grain yield of indicia cultivar by 19.2%, 10.8% and 21.9%, and the respective reductions in japonica cultivar were 39.7%, 25.3% and 47.3%, re- spectively. However, no significant difference was detected for T4 treatment. During rice co-culture with barnyardgrass, T1, T2 and T3 significantly reduced rice dry matter accumulation at maturity, flag leaf photosynthetic rate, root oxidation activity and the activity of adenosine triphosphate enzyme (ATPsse) in rice grains at the filling stage, and the magnitude of decrease was in the order of T3 > T1 > T2, while no significant difference was observed between T4 and CK. In addition, all treatments had no effects on the final tiller number and plant height of rice. It indicated that the negative effect of barnyardgrass on rice growth and yield differed among the four species of barnyardgrass, in the order of T3 > T1 > T2 > T4. Barnyardgrass reduced the flag leaf photosynthetic rate of rice, both root oxidation activity and ATPsse activity in grains, which resulted in the reduction in final productivity of rice when co-cultured with barnyardgrass.

  6. Effect of allelochemical tricin and its related benzothiazine derivative on photosynthetic performance of herbicide-resistant barnyardgrass.

    Science.gov (United States)

    Yang, Xue-Fang; Lei, Kang; Kong, Chui-Hua; Xu, Xiao-Hua

    2017-11-01

    Despite increasing knowledge of allelochemicals as leads for new herbicides, relatively little is known about the mode of action of allelochemical-based herbicides on herbicide-resistant weeds. In this study, herbicidal activities of a series of allelochemical tricin-derived compounds were evaluated. Subsequently, a benzothiazine derivative 3-(2-chloro-4-methanesulfonyl)-benzoyl-hydroxy-2-methyl-2H-1,2-benzothiazine-1,1-dioxide with 4-hydroxyphenyl-pyruvate dioxygenase (HPPD) inhibiting activity was identified as a target compound on photosynthetic performance of penoxsulam-resistant versus -susceptible barnyardgrass (Echinochloa crus-galli). Regardless of barnyardgrass biotype, the benzothiazine derivative greatly affected chlorophyll fluorescence parameters (Fv/Fm, ETR 1min and NPQ 1min ), reduced the chloroplast fluorescence levels and expression of HPPD gene. In particular, the benzothiazine derivative interfered with photosynthetic performance of resistant barnyardgrass more effectively than the allelochemical tricin itself. These results showed that the benzothiazine derivative effectively inhibited the growth of resistant barnyardgrass and its mode of action on photosynthesis system was similar to HPPD-inhibiting sulcotrione, making it an ideal lead compound for further development of allelochemical-based herbicide discovery. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Emergence dynamics of barnyardgrass and jimsonweed from two depths when switching from conventional to reduced and no-till conditions

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    Vasileios P. Vasileiadis

    2016-03-01

    Full Text Available A cylinder experiment was conducted in northern Greece during 2005 and 2006 to assess emergence dynamics of barnyardgrass (Echinochloa crus-galli (L. Beauv. and jimsonweed (Datura stramonium L. in the case of a switch from conventional to conservation tillage systems (CT. Emergence was surveyed from two burial depths (5 and 10 cm and with simulation of reduced tillage (i.e. by soil disturbance and no-till conditions. Barnyardgrass emergence was significantly affected by burial depth, having greater emergence from 5 cm depth (96% although even 78% of seedlings emerged from 10 cm depth after the two years of study. Emergence of barnyardgrass was stable across years from the different depths and tillage regimes. Jimsonweed seeds showed lower germination than barnyardgrass during the study period, whereas its emergence was significantly affected by soil disturbance having 41% compared to 28% without disturbance. A burial depth x soil disturbance interaction was also determined, which showed higher emergence from 10 cm depth with soil disturbance. Jimsonweed was found to have significantly higher emergence from 10 cm depth with soil disturbance in Year 2. Seasonal emergence timing of barnyardgrass did not vary between the different burial depth and soil disturbance regimes, as it started in April and lasted until end of May in both years. Jimsonweed showed a bimodal pattern, with first emergence starting end of April until mid-May and the second ranging from mid-June to mid-August from 10 cm burial depth and from mid-July to mid-August from 5 cm depth, irrespective of soil disturbance in both cases.

  8. Emergence dynamics of barnyardgrass and jimsonweed from two depths when switching from conventional to reduced and no-till conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vasileiadis, V.; Froud-Williams, R.J.; Loddo, D.; Eleftherohorinos, I.G.

    2016-11-01

    A cylinder experiment was conducted in northern Greece during 2005 and 2006 to assess emergence dynamics of barnyardgrass (Echinochloa crus-galli (L.) Beauv.) and jimsonweed (Datura stramonium L.) in the case of a switch from conventional to conservation tillage systems (CT). Emergence was surveyed from two burial depths (5 and 10 cm) and with simulation of reduced tillage (i.e. by soil disturbance) and no-till conditions. Barnyardgrass emergence was significantly affected by burial depth, having greater emergence from 5 cm depth (96%) although even 78% of seedlings emerged from 10 cm depth after the two years of study. Emergence of barnyardgrass was stable across years from the different depths and tillage regimes. Jimsonweed seeds showed lower germination than barnyardgrass during the study period, whereas its emergence was significantly affected by soil disturbance having 41% compared to 28% without disturbance. A burial depth x soil disturbance interaction was also determined, which showed higher emergence from 10 cm depth with soil disturbance. Jimsonweed was found to have significantly higher emergence from 10 cm depth with soil disturbance in Year 2. Seasonal emergence timing of barnyardgrass did not vary between the different burial depth and soil disturbance regimes, as it started in April and lasted until end of May in both years. Jimsonweed showed a bimodal pattern, with first emergence starting end of April until mid-May and the second ranging from mid-June to mid-August from 10 cm burial depth and from mid-July to mid-August from 5 cm depth, irrespective of soil disturbance in both cases. (Author)

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

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    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

  10. Co-composting of sewage sludge and Echinochloa pyramidalis (Lam.)

    African Journals Online (AJOL)

    Yaoundé-Cameroon) in order to assess the effect of three sewage sludge: Macrophyte ratios on the co-composting process and compost quality. The ratios were T1: 25 kg of plant material (Echinochloa pyramidalis) and 75 kg sludge; T2: 50 kg ...

  11. The economic potential of Echinochloa pyramidalis (Lam.) Hitchc ...

    African Journals Online (AJOL)

    Cameroon, like other developing countries, faces major problems in the urban centres such as high rate of population increase, food and ruminant feed shortages as well as inadequate access to sanitation. However, Echinochloa pyramidalis, well-known forage adapted to the drying vegetated beds for wastewater and ...

  12. Resistance to quinclorac caused by the enhanced ability to detoxify cyanide and its molecular mechanism in Echinochloa crus-galli var. zelayensis.

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    Gao, Yuan; Pan, Lang; Sun, Yu; Zhang, Teng; Dong, Liyao; Li, Jun

    2017-11-01

    Quinclorac, an auxin-type herbicide, is widely used to control barnyardgrass and some dicotyledon weeds. Echinochloa crus-galli var. zelayensis, a variety of E. crus-galli (L.) Beauv., is widespread in China and some populations have resistance to quinclorac. E. crus-galli var. zelayensis seeds with varying sensitivity to quinclorac were used in the present study. The expression of the ADP/ATP carrier protein (ANT) gene, which plays an important role in the maintenance of cellular energy balance, dramatically rose in the S biotype after exposure to quinclorac, while no change was found in two R biotypes. The activity of β-cyanoalanine synthase (β-CAS), which is the key enzyme for cyanide degradation, was higher in two R biotypes than in the S biotype before and after treatment with quinclorac. One single-nucleotide difference was detected in the EcCAS gene of two R biotypes compared with the S biotype. The nucleotide change, which caused one amino acid substitution, replacing Methionine (Met)-295 with Lysine (Lys)-295 in the two R biotypes, which are same as the rice β-CAS gene at this position. In addition, EcCAS gene expression was higher in the two R biotypes than in the S biotype. In conclusion, β-CAS may play a crucial role in the resistance of E. crus-galli var. zelayensis to quinclorac. EcCAS gene mutation and higher gene expression may enhance the activity of β-CAS to avoid the accumulation of toxic cyanide in resistant populations, thus contributing to the resistance mechanism of E. crus-galli var. zelayensis. to quinclorac. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. The effect of local population of Ustilago trichophora on Echinochloa crus-galli

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    Wojciech Pusz

    2014-08-01

    Full Text Available Ustilago trichophora is a pathogenic fungus infecting the grass of Echinochloa genus. The effect of this pathogen on the growth of Echinochloa was not yet described. Ustilago trichophora was found and described first time in Poland in 1998 on Echinochloa crus-galli specimen. ThenU. trichophora was found in several places in the region of Lower Silesia in the following years. The aim of the investigation was to study the effects of Ustilago trichophora on the biometric parameters of plants as well as of seeds of Echinochloa crus-galli. The infected specimens of barnyards grass were found lower, they displayed poorer tillering and they produced a smaller number of panicles than the healthy plants. Seeds from infected bunches weight, were characterized by lower germination and energy capacity than the control ones.

  14. Integration of C4-specific ppdk gene of Echinochloa to C3 upland ...

    African Journals Online (AJOL)

    Pyruvate orthophosphate dikinase (PPDK) plays a key role in C4 photosynthetic pathway. The enzymatic reaction is one of the rate-limiting steps of the C4 photosynthetic pathway. In this paper, the gene encoding Echinochloa pyruvate orthosphate dikinase (GenBank accession number: AB289641) was introduced into H65 ...

  15. Uso da água por plantas de arroz em competição com biótipos de Echinochloa crusgalli resistente e suscetível ao herbicida quinclorac Water use by rice plants under competition with Echinochloa crusgalli biotypes resistant and susceptible to quinclorac

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    G. Concenço

    2009-06-01

    de arroz quando em interação com outros fatores.The objective of this work was to evaluate the characteristics related to water use efficiency of rice plants, under competition with different densities of Echinochloa crusgalli plants. The trial was installed under greenhouse conditions, in a completely randomized block design, and factorial scheme 2 x 6 (two biotypes and six infestation densities, with four replications. The treatments consisted of one rice plant at the center of the plot, under competition with 0, 1, 2, 3, 4 or 5 plants of Echinochloa crusgalli, resistant or susceptible to quinclorac, at the periphery of the plot. Fifty days after emergence, water vapor stomatal conductance, sub-stomatal water pressure, leaf temperature and transpiration rate were evaluated, as well as water use efficiency. The plants were cut at the soil level and put into paper bags and dried at 70 ± 1 ºC until dry mass stabilization. Data were analyzed by the F-test and, in case of significance, submitted to the DMRT test to evaluate the effect of increasing competition with Echinochloa over the rice plants, and to DMS test to compare the rice plants submitted to the biotypes at each competition level. Rice plants were more affected as the barnyardgrass density increased, but differences related to the biotype were not observed. Important variables, such as water use efficiency, were more affected when rice plants were under competition with plants of the susceptible biotype. Under field conditions, this characteristic may not be relevant to rice plant development, when interacted with other factors.

  16. Comparison of physiological and anatomical changes of C3 (Oryza sativa [L.]) and C4 (Echinochloa crusgalli [L.]) leaves in response to drought stress

    Science.gov (United States)

    Hamim, Hamim; Banon, Sri; Dorly, Dorly

    2016-01-01

    The experiment aimed to analyse the different response of C3 (Oryza sativa L.) and C4 (Echinochloa crusgalli L.) species to drought stress based on physiological and anatomical properties. Seeds of rice (Oryza sativa) and Echinochloa (Echinochloa crusgalli) were grown in 15 cm (D) pot for 6 weeks under well-watered conditions. After 6 weeks the plants were divided into two groups, (1) well-watered which were watered daily, and (2) drought stress which were withheld from watering for 6 days. After 6 days of drought, the plants were then re-watered to analyse plant recovery. During drought period, the plants were analysed for growth, leaf relative water content (RWC), photosynthesis, and leaf anatomy. Drought stress significantly reduced leaf RWC of both species, but the reduction was bigger in rice than in Echinochloa. The maximum efficiency of photosynthesis (Fv/Fm) was decrease significantly in response to drought stress by about 48.04% in rice, while it was only 34.40% in Echinochloa. Anatomical analysis showed drought treatment tended to reduce leaf thickness in the area of bulliform cell, major- as well as intervein and xylem diameter, more in Echinochloa than in rice, suggesting that the decrease of vein and xylem diameter is among the anatomical parameters that is important to overcome from drought stress in Echinochloa. The number of chloroplast in the mesophyll cell and bundle sheath cell (BSC) was different between these two species, where in Echinochloa chloroplast was found in both mesophyll as well as BSC, while in rice it was only found in mesophyll cell, confirmed that Echinochloa is a C4 and rice is a C3 species. Interestingly, in Echinochloa, the number of chloroplast was significantly increased due to drought stress in BSC, but not in mesophyll cell. The number of starch granules also dramatically increased in response to drought in the mesophyll cells of rice and Echinochloa, and in the bundle sheath cell of Echinochloa which indicate that C3

  17. Anaerobiosis and ethanol effects on germination, growth, and protein synthesis of five Echinochloa species

    International Nuclear Information System (INIS)

    Dybiec, L.D.; Rumpho, M.E.; Kennedy, R.A.

    1989-01-01

    Five Echinochloa species, encompassing a spectrum from flood tolerant to flood intolerant, were studied to determine the mechanisms of anaerobic germination and growth. Seeds were germinated in air or N 2 , plus 0, 1 or 3% ethanol, and germination rates and growth measurements recorded for 7 days. In air or N 2 increasing ethanol levels did not affect total germination per se, although the rate of germination was delayed in N 2 . Shoot/root lengths in air were highest for tolerant species and increased with increasing ethanol, whereas, in intolerant species, shoot/root lengths decreased with increasing ethanol. Aerobic vs. anaerobic polypeptide profiles of each of the species were compared by SDS/PAGE. For all species, the number of polypeptides decreased under anaerobiosis and several quantitative differences were apparent relative to the aerobic profile. In addition, amino acid incorporation into protein was analyzed by [ 35 S]-Met labeling of 3 day old seedlings grown in air or N 2 . Significant protein synthesis was measured in tolerant seedlings under N 2 and several polypeptides were specifically induced. These results are being compared with labeling patterns of the other semi-tolerant and intolerant Echinochloa species to determine their importance in flooding tolerance

  18. Detecting ALS and ACCase herbicide tolerant accession of Echinochloa oryzoides (Ard.) Fritsch. in rice (Oryza sativa L.) fields

    DEFF Research Database (Denmark)

    Altop, Emine Kaya; Mennan, Husrev; Streibig, Jens Carl

    2014-01-01

    Inconsistent control of Echinochloa oryzoides has been reported repeatedly by farmers in the major rice growing area of Turkey. Greenhouse studies confirmed the existence of cross and multiple herbicide tolerance of E.oryzoides accessions including acetolactate synthase (penoxsulam, bispyribac-so...

  19. Toleransi Galur Harapan Padi Sawah (Oryza sativa L. pada Persaingan dengan Gulma Echinochloa crus-galli

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    Usman ,

    2016-10-01

    Full Text Available ABSTRACTBarnyard grass (Echinochloa crus-galli (L. P. Beauv. is a major weed competitor to rice production in Indonesia. In order to develop integrated weed management program, a research to select competitive rice lines to E. crus-galli was conducted in a green house of Indonesian Centre of Agricultural Biotechnology and Genetic Resource Research and Development Bogor. The research design was split plot with four replications, E. crus-galli was designed as the main plot (rice without E. crus-galli compared  rice with four E. crus-galli per pot, and the sub-plots were 25 genotypes (23 lines, 1 tolerant variety and 1 sensitive variety. Level of tolerance was determined by the reduction percentage of grains weight, the number of productive tillers and dry matter weight. The results showed that rice competition with E. crus-galli reduced plant height, productive tiller numbers, filled spikelet numbers per panicle, dry matter weight and dry grain weight. Three lines, i.e., IR10L-155, IR10L-133 and BIO-R84-1 were classified as tolerant, 19 lines were moderate and 3 lines were sensitive to E. crus-galli competition.Keywords: Barnyard grass, competition, sensitive line, yield reduction

  20. Antimicrobial and antioxidant activities of echinochloa colona (linn.) link and sporobolus coromandelianus (retz.) kunth

    International Nuclear Information System (INIS)

    Ajaib, M.; Khan, K.M.

    2013-01-01

    Antimicrobial and antioxidant activities of two plants Echinochloa colona (Linn.) Link and Sporobolus coromandelianus (Retz.) Kunth, were carried out. The results revealed that the extracts of both plants were active against Gram positive bacteria, i.e. Staphylococcus aureus and Streptococcus pneumoniae and Gram negative bacteria, i.e. Escherichia coli and Pseudomonas aeruginosa as well as the fungal strains Aspergillus oryzae and Aspergillus niger. The most significant results were obtained from the methanolic and petroleum ether extracts of E. colona, i.e. 24 +- 2.64 mm and 23 +- 2.64 mm against S. aureus, respectively. A significant inhibition zone of 23.66 +- 1.52 was observed by petroleum ether extract of S. coromandelianus. The chloroform extracts of S. coromandelianus showed an inhibition zone 72.33 +- 4.09 mm against A. oryzae and 66.33 +- 1.15 mm against A. niger. The antioxidant activity was evaluated using five approaches, i.e. 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulphonic acid (ABTS) method; ferric reducing antioxidant power (FRAP) assay, metal chelating assay, total phenolic contents (TPC) and flavonoid contents. The results showed that the methanolic extracts of both plants possessed significant antioxidant activity. The results also indicated that methanolic extract of E. colona had total phenolic and flavonoid contents, i.e. 734.25 and 7774.54 mg/ml, however, methanolic extract of S. coromandelianus had phenolic and flavonoid contents, i.e. 366.75 and 3010.90 mg/ml. (author)

  1. Accumulation and localization of cadmium in Echinochloa polystachya grown within a hydroponic system

    International Nuclear Information System (INIS)

    Solis-Dominguez, F.A.; Gonzalez-Chavez, M.C.; Carrillo-Gonzalez, R.; Rodriguez-Vazquez, R.

    2007-01-01

    Phytoremediation is a technology for extracting or inactivating pollutants. Echinochloa polystachya [(H.B.K.) Hitchcock] (Poaceae) is a fast-growing perennial grass that is common in tropical areas and is often found in oil-polluted soils that contain high concentrations of heavy metals. However, its tolerance to heavy metals, and its ability to accumulate them, has yet to be investigated. Here we test the hypothesis that E. polystachya is able to accumulate high concentrations of cadmium (Cd). Plants were grown hydroponically with different levels of Cd 2+ (0, 0.25, 1, 2, 10, 50, and 100 mg L -1 ), and were found to be tolerant to Cd 2+ at all levels. No metal-toxicity symptoms were observed at any Cd 2+ level. Root and leaves Cd concentrations were 299 ± 13.93 and 233 ± 8.77 mg kg -1 (on a dry weight basis), respectively. Scanning electron microscopy showed the inclusion of Cd within the xylem; this result was confirmed by energy dispersive X-ray spectrometry. Leaf tissues also accumulated Cd, especially within the bulliform cells of the epidermis. We conclude that E. polystachya is a hyperaccumulator of Cd. While data for other metals are not yet available, E. polystachya shows promise in the phytoextraction of Cd from polluted tropical sites

  2. Competitividade relativa entre cultivares de arroz irrigado e biótipo de capim-Arroz (Echinochloa spp.)

    OpenAIRE

    Agostinetto,D.; Galon,L.; Moraes,P.V.D.; Rigoli,R.P.; Tironi,S.P.; Panozzo,L.E.

    2008-01-01

    As espécies pertencentes ao gênero Echinochloa se destacam como principais infestantes das lavouras de arroz irrigado do Rio Grande do Sul, causando dano econômico à cultura devido à elevada competitividade pelos recursos do ambiente. O trabalho teve por objetivo comparar as habilidades competitivas relativas entre dois cultivares de arroz e um biótipo de capim-arroz. Para isso, foram realizados experimentos em casa de vegetação na estação de crescimento 2006/07, em delineamento experimental ...

  3. Glyphosate resistance in Echinochloa colona: phenotypic characterisation and quantification of selection intensity.

    Science.gov (United States)

    Goh, Sou Sheng; Vila-Aiub, Martin M; Busi, Roberto; Powles, Stephen B

    2016-01-01

    A population of Echinochloa colona infesting agricultural fields in the northern region of Western Australia evolved glyphosate resistance after 10 years of glyphosate selection. This study identified two phenotypic (susceptible S versus resistant R) lines from within a segregating glyphosate-resistant population. Estimation of survival, growth and reproductive rates of the phenotypes in response to glyphosate selection helped to characterise the level of resistance, fitness and the selection intensity for glyphosate in this species. Estimations of LD(50) (lethal dose) and GR(50) (growth rate) showed an eightfold glyphosate resistance in this population. The resistant index based on the estimation of seed number (SY(n50)) showed a 13-fold resistance. As a result of linear combination of plant survival and fecundity rates, plant fitness values of 0.2 and 0.8 were estimated for the S and R phenotypes when exposed to the low dose of 270 g glyphosate ha(-1). At the recommended dose of 540 g glyphosate ha(-1) , fitness significantly decreased (fivefold) in S plants but remained markedly similar (0.7) in plants of the R phenotype. Thus, the calculated selection intensity (SI) at 540 g glyphosate ha(-1) was much greater (SI = 17) than at 270 g glyphosate ha(-1) (SI = 4). The assessment of plant survival and fecundity in response to glyphosate selection in the S and R phenotypes allowed a greater accuracy in the estimation of population fitness of both phenotypes and thus of glyphosate selection intensity in E. colona. The estimation of seed number or mass of phenotypes under herbicide selection is a true ecological measure of resistance with implications for herbicide resistance evolution. © 2015 Society of Chemical Industry.

  4. Seed germination ecology of Echinochloa glabrescens and its implication for management in rice (Oryza sativa L.).

    Science.gov (United States)

    Opeña, Jhoana L; Chauhan, Bhagirath S; Baltazar, Aurora M

    2014-01-01

    Echinochloa glabrescens is a C4 grass weed that is very competitive with rice when left uncontrolled. The competitive ability of weeds is intensified in direct-seeded rice production systems. A better understanding is needed of factors affecting weed seed germination, which can be used as a component of integrated weed management in direct-seeded rice. This study was conducted to determine the effects of temperature, light, salt and osmotic stress, burial depth, crop residue, time and depth of flooding, and herbicide application on the emergence, survival, and growth of two populations [Nueva Ecija (NE) and Los Baños (IR)] of E. glabrescens. Seeds from both populations germinated at all temperatures. The NE population had a higher germination rate (88%) from light stimulation than did the IR population (34%). The salt concentration and osmotic potential required to inhibit 50% of germination were 313 mM and -0.24 MPa, respectively, for the NE population and 254 mM and -0.33 MPa, respectively, for the IR population. Emergence in the NE population was totally inhibited at 4-cm burial depth in the soil, whereas that of the IR population was inhibited at 8 cm. Compared with zero residue, the addition of 5 t ha(-1) of rice residue reduced emergence in the NE and IR populations by 38% and 9%, respectively. Early flooding (within 2 days after sowing) at 2-cm depth reduced shoot growth by 50% compared with non-flooded conditions. Pretilachlor applied at 0.075 kg ai ha(-1) followed by shallow flooding (2-cm depth) reduced seedling emergence by 94-96% compared with the nontreated flooded treatment. Application of postemergence herbicides at 4-leaf stage provided 85-100% control in both populations. Results suggest that integration of different strategies may enable sustainable management of this weed and of weeds with similar germination responses.

  5. Seed germination ecology of Echinochloa glabrescens and its implication for management in rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Jhoana L Opeña

    Full Text Available Echinochloa glabrescens is a C4 grass weed that is very competitive with rice when left uncontrolled. The competitive ability of weeds is intensified in direct-seeded rice production systems. A better understanding is needed of factors affecting weed seed germination, which can be used as a component of integrated weed management in direct-seeded rice. This study was conducted to determine the effects of temperature, light, salt and osmotic stress, burial depth, crop residue, time and depth of flooding, and herbicide application on the emergence, survival, and growth of two populations [Nueva Ecija (NE and Los Baños (IR] of E. glabrescens. Seeds from both populations germinated at all temperatures. The NE population had a higher germination rate (88% from light stimulation than did the IR population (34%. The salt concentration and osmotic potential required to inhibit 50% of germination were 313 mM and -0.24 MPa, respectively, for the NE population and 254 mM and -0.33 MPa, respectively, for the IR population. Emergence in the NE population was totally inhibited at 4-cm burial depth in the soil, whereas that of the IR population was inhibited at 8 cm. Compared with zero residue, the addition of 5 t ha(-1 of rice residue reduced emergence in the NE and IR populations by 38% and 9%, respectively. Early flooding (within 2 days after sowing at 2-cm depth reduced shoot growth by 50% compared with non-flooded conditions. Pretilachlor applied at 0.075 kg ai ha(-1 followed by shallow flooding (2-cm depth reduced seedling emergence by 94-96% compared with the nontreated flooded treatment. Application of postemergence herbicides at 4-leaf stage provided 85-100% control in both populations. Results suggest that integration of different strategies may enable sustainable management of this weed and of weeds with similar germination responses.

  6. Multifunctionalised benzoxazinones in the systems Oryza sativa-Echinochloa crus-galli and Triticum aestivum-Avena fatua as natural-product-based herbicide leads.

    Science.gov (United States)

    Macías, Francisco A; Chinchilla, Nuria; Arroyo, Elena; Varela, Rosa M; Molinillo, José M G; Marín, David

    2010-10-01

    Fifteen novel derivatives of D-DIBOA, including aromatic ring modifications and the addition of side chains in positions C-2 and N-4, had previously been synthesised and their phytotoxicity on standard target species (STS) evaluated. This strategy combined steric, electronic, solubility and lipophilicity requirements to achieve the maximum phytotoxic activity. An evaluation of the bioactivity of these compounds on the systems Oryza sativa-Echinochloa crus-galli and Triticum aestivum-Avena fatua is reported here. All compounds showed inhibition profiles on the two species Echinochloa crus-galli (L.) Beauv. and Avena fatua L. The most marked effects were caused by 6F-4Pr-D-DIBOA, 6F-4Val-D-DIBOA, 6Cl-4Pr-D-DIBOA and 6Cl-4Val-D-DIBOA. The IC(50) values for the systems Echinochloa crus-galli-Oryza sativa and Avena fatua-Triticum aestivum for all compounds were compared. The compound that showed the greatest selectivity for the system Echinochloa crus-galli-Oryza sativa was 8Cl-4Pr-D-DIBOA, which was 15 times more selective than the commercial herbicide propanil (Cotanil-35). With regard to the system Avena fatua-Triticum aestivum, the compounds that showed the highest selectivities were 8Cl-4Val-D-DIBOA and 6F-4Pr-D-DIBOA. The results obtained for 6F-4Pr-D-DIBOA are of great interest because of the high phytotoxicity to Avena fatua (IC(50) = 6 µM, r(2) = 0.9616). The in vitro phytotoxicity profiles and selectivities shown by the compounds described here make them candidates for higher-level studies. 8Cl-4Pr-D-DIBOA for the system Echinochloa crus-galli-Oryza sativa and 6F-4Pr-D-DIBOA for Avena fatua-Triticum aestivum were the most interesting compounds.

  7. Allelopathic potential of rice residues of selected rice varieties (Oryza sativa L. against Echinochloa crus-galli

    Directory of Open Access Journals (Sweden)

    AS Ranagalage

    2014-12-01

    Full Text Available Allelopathic potential of rice residues of selected rice varieties (Oryza sativa L. against Echinochloa crus-galliAbstract Allelopathic compounds will play a vital role in sustainable weed control in paddy cultivation in future. Exploitation and implementation of this technology in weed management has been considered as ecologically sound, resource conserving and economically viable method.  The objective of this study was to assess the allelopathic traits of rice residues of selected (Bg359, Ld365, Bg407, At401, Bg358, At362, At402, Bg450, Bg300, Herathbanda and Handiran rice cultivars to control of barnyard grass (Echinochloa crus-galli one of the most destructive weed in Sri  Lankan paddy ecosystem. Completely Randomize Design was used with three replicates for each cultivar. According to the research findings, significant differences (p≤0.05 were observed among cultivars and amount of residue mixed with sand (2.0, 4.0, 6.0g of ground residue per 500.0g of sand in terms of barnyard grass plant height, number of leaves, germination and total dry weight. Among those measured variables germination and dry matter of barnyard grass showed significant reduction when increasing amount of rice residue. Among different cultivars used Ld365 showed the highest inhibition % for all above measured variables and the lowest was the Herathbanda. As an example the inhibition percentages of plant height, seed germination and shoot dry weight of Ld365 were 60%, 56% and 65% respectively. In contrast, rice cultivar Herathbanda caused 27%, 26% and 26% inhibition respectively for above mentioned parameters. When comparing  three levels of rice residue mixture   63% dry weight reduction was observed  in 6.0g rice residue  and (51%  4.0g and 27% with  2.0g  mixture. Furthermore percentage germination also reduced with increased amount of rice residue mixture. It indicated that highest in 6.0g, which is 49% closely followed by 4.0g (41% and the lowest is

  8. Influence of growth regulators on somatic embryogenesis, plantlet regeneration, and post-transplant survival of Echinochloa frumentacea.

    Science.gov (United States)

    Sankhla, A; Davis, T D; Sankhla, D; Sankhla, N; Upadhyaya, A; Joshi, S

    1992-07-01

    After placement on Murashige and Skoog's basal medium supplemented with 3-5 mg/l 2,4-D, immature inflorescence expiants of Echinochloa frumentacea gave rise to three distinct types of callus: a) loosely arranged and soft; b) compact and translucent; c) compact, sticky and mucilaginous. Somatic embryo formation occurred in type 'b' callus in about 18-24 d. Callus types 'a' and 'c' did not produce somatic embryos. The highest percentage of cultures exhibiting somatic embryogenesis occurred on the medium containing 5 mg/l 2,4-D and 0.5 mg/l kinetin. Somatic embryos also formed directly on the inflorescence (without intervening callus formation) in about 15% of the expiants placed on this medium. The addition of paclobutrazol or uniconazole (0.25 or 1 mg/l) to the medium had no influence on the percentage of cultures exhibiting direct somatic embryogenesis, but paclobutrazol slightly increased the mean number of somatic embryos per culture. Many of the callus-derived somatic embryos germinated when subcultured on basal MS medium supplemented with kinetin. Addition of paclobutrazol or uniconazole to the culture medium at 0.25 or 1 mg/l decreased somatic embryo germination and shoot elongation but increased root length and leaf width. Both paclobutrazol and uniconazole increased survival of the plantlets following transplanting to soil. Increased post-transplant survival was accompanied by reduced water loss from plantlets produced on culture media containing triazoles.

  9. Construction of a comparative RFLP map of Echinochloa crus-galli toward QTL analysis of flooding tolerance.

    Science.gov (United States)

    Fukao, T; Paterson, A H; Hussey, M A; Yamasue, Y; Kennedy, R A; Rumpho, M E

    2004-04-01

    To analyze quantitative trait loci (QTLs) affecting flooding tolerance and other physiological and morphological traits in Echinochloa crus-galli, a restriction fragment length polymorphism (RFLP) map was constructed using 55 plants of the F(2) population ( E. crus-galli var. praticola x E. crus-galli var. formosensis). One hundred forty-one loci formed 41 linkage groups. The total map size was 1,468 cM and the average size of linkage groups was 35.8 cM. The average distance between markers was 14.7 cM and the range was 0-37.2 cM. Early comparisons to the genetic maps of other taxa suggest appreciable synteny with buffelgrass ( Pennisetum spp.) and sorghum ( Sorghum spp.). One hundred ninty-one F(2) plants were used to analyze QTLs of flooding tolerance, plant morphology, heading date, number of leaves, and plant height. For flooding tolerance, two QTLs were detected and one was mapped on linkage group 24. Other traits, including plant morphology, heading date, number of leaves, and plant height were highly correlated. Three genomic regions accounted for most of the mapped QTLs, each explaining 2-4 of the significant marker-trait associations. The high observed correlation between the traits appears to result from QTLs with a large contribution to the phenotypic variance at the same or nearby locations.

  10. Estabelecimento de Echinochloa polystachya (H.B.K. Hitchcock (Poaceae em solo de várzea contaminado com petróleo de Urucu Establishment of Echinochloa polystachya (HBK Hitchcock in varzea soil contaminated with Urucu's petroleum

    Directory of Open Access Journals (Sweden)

    Aline Lopes

    2009-09-01

    Full Text Available A utilização de plantas para fitorremediação do solo requer que a concentração do poluente esteja dentro dos limites de tolerância da planta para que o tratamento seja eficaz. O rebrotamento e crescimento da herbácea aquática Echinochloa polystachya em solo de várzea contaminado por petróleo de Urucu foram estudados por meio do plantio de propágulos em frascos com 2 L de solo contaminado pela mistura de 7 dosagens de petróleo, distribuídas entre 0 e 0,46 L m-2. O experimento foi realizado em Casa de Vegetação e as plantas foram monitoradas durante 70 dias. Em resposta ao aumento da dosagem do petróleo, houve diminuição da biomassa aérea, da proporção de biomassa aérea viva/aérea total, do comprimento da folha e do número de folhas. A interação entre dosagem e tempo de exposição levou à diminuição do número de folhas, comprimento da folha, altura de inserção da primeira folha e aumento do número de folhas com comprometimento fitossanitário. A utilização de E. polystachya para fitorremediação pode estar limitada a solos com baixas dosagens de petróleo de Urucu.The use of plants for the phytoremediation of contaminated soils requires that the concentrations of the pollutant lay within the limits of tolerance of the plant in order to ensure the efficacy of the treatment. The vegetative propagation and growth of the aquatic herbaceous plant Echinochloa polystachya were studied by planting parts of stems in 2 L of várzea soils previously contaminated by crude oil from Urucu, in 7 different dosages of oil ranging from 0 to 0.46 L m-2. The experiment took place in a green house and the plants were monitored during a 70 days period. Increasing the oil concentration lead to the decrease of the above-ground biomass, the ratio alive aerial biomass/total aerial biomass, leaf length and number of leaves. The interaction between dosage and time of exposition contributed for a reduction in the number and length of

  11. Método rápido para detecção de resistência de capim-arroz (Echinochloa spp. ao quinclorac A quick method for detecting resistance of Echinochloa spp. to quinclorac

    Directory of Open Access Journals (Sweden)

    G. Concenço

    2008-06-01

    Full Text Available Considerando-se que a resistência de capim-arroz ao quinclorac está amplamente distribuída nas lavouras do Rio Grande do Sul e de Santa Catarina e que o "teste-padrão" para distinção de biótipos resistentes a esse herbicida é demorado, torna-se necessário o desenvolvimento de um "teste rápido" para identificação de propágulos desses biótipos. Para isso, foram realizados dois experimentos: um em casa de vegetação (teste-padrão e o outro em laboratório (teste rápido. No ensaio em laboratório, sementes de quatro biótipos de capim-arroz, caracterizados como resistentes ou suscetíveis ao quinclorac, foram semeadas em papel germitest umedecido com soluções de 0; 3,75; 18,75; 37,5; 187,5; 375; e 1.875 mg L-1 do herbicida durante 14 dias a 25 ºC. Em casa de vegetação, os mesmos tratamentos foram avaliados cultivando-se os biótipos de capim-arroz em vasos com 10 L de solo. Neste ensaio foram avaliados massa seca e altura de plantas aos 25 dias após emergência (DAE, e no ensaio em laboratório, percentagem de sobrevivência aos 7 dias após semeadura (DAS, massa seca e comprimento da parte aérea das plantas aos 14 DAS. O teste em laboratório é mais rápido, exige menos tempo, recursos humanos e materiais, com a mesma eficiência que o teste em casa de vegetação e com a vantagem adicional de permitir aferições quanto ao nível de resistência entre biótipos resistentes. Sugere-se que a concentração de 375 mg L-1 de quinclorac seja usada como padrão no teste rápido, pois apresenta adequada margem de segurança como indicadora da presença de sementes resistentes, com porcentagem de sobrevivência igual a zero para plântulas dos biótipos suscetíveis ao quinclorac.Given that resistance of Echinochloa sp. to quinclorac is widely distributed in rice fields in the states of Rio Grande do Sul and Santa Catarina, and that the standard tests are relatively slow in showing resistance, a quick test must be developed to

  12. Efecto de la profundidad y manejo de la lámina de agua en la emergencia y crecimiento de Echinochloa crus-galli.

    OpenAIRE

    Jorge García de la Osa; Bárbara Odalis Gómez Fernández

    2007-01-01

    En el Centro internacional Tsukuba, Japón fueron realizados ensayos en condiciones de macetas con el propósito de evaluar el efecto que producen diferentes niveles y manejos de agua sobre la emergencia y crecimiento de Echinochloa crus-galli P. Beauv. var. crus-galli. Se determinó que el aumento de la lámina de agua ejerció dos efectos sobre E. crus-galli, el retraso en el crecimiento que se manifestó de forma significativa a partir de una lámina de 5 cm y el de disminución de la cantidad d...

  13. Interferência e nível de dano econômico de capim-arroz sobre o arroz em função do arranjo de plantas da cultura Interference and economic weed threshold (Ewt of barnyardgrass on rice as a function of crop plant arrangement

    Directory of Open Access Journals (Sweden)

    D. Agostinetto

    2010-01-01

    Full Text Available Na cultura do arroz irrigado ocorrem elevadas perdas de produtividade de grãos devido à interferência de plantas daninhas, pois estas também estão adaptadas ao ambiente inundado de cultivo do cereal. Objetivou-se avaliar a interferência e determinar o nível de dano econômico de populações de capim-arroz em arroz irrigado em função do arranjo de plantas da cultura. Foi realizado um experimento em campo, com cultivo de arroz em sistema convencional. Os tratamentos foram constituídos por três arranjos de plantas de arroz, cultivar BRS Pelota (17 e 32 cm e semeadura a lanço, e nove populações de capim-arroz em cada método de semeadura. O modelo de regressão não linear da hipérbole retangular estima adequadamente as perdas de produtividade do arroz irrigado na presença de plantas de capim-arroz. A cultura do arroz semeada a lanço apresenta maior habilidade competitiva com o capim-arroz em relação à semeadura em linha nos espaçamentos de 17 e 32 cm. A variável área foliar apresenta melhor ajuste ao modelo da hipérbole retangular, comparativamente às variáveis população de plantas, massa seca da parte aérea e cobertura do solo. A utilização de semeadura a lanço aumenta o nível de dano econômico, justificando a adoção de medidas de controle do capim-arroz em níveis mais elevados de população. Acréscimo na produtividade de grãos, no preço do arroz e na eficiência do herbicida e redução no custo de controle diminuem os valores do nível de dano econômico, justificando a adoção de medidas de controle em baixas populações de capim-arroz.High yield losses in irrigated rice occur due to weed interference, as weeds are also adapted to the flooded environment where the crop is cultivated. The objective of this study was to evaluate the degree of interference and determine the economic weed threshold of populations of barnyardgrass in irrigated rice, according to crop arrangement. Thus, an experiment was

  14. A New Ala-122-Asn Amino Acid Change Confers Decreased Fitness to ALS-Resistant Echinochloa crus-galli.

    Science.gov (United States)

    Panozzo, Silvia; Scarabel, Laura; Rosan, Valentina; Sattin, Maurizio

    2017-01-01

    Gene mutations conferring herbicide resistance may cause pleiotropic effects on plant fitness. Knowledge of these effects is important for managing the evolution of herbicide-resistant weeds. An Echinochloa crus-galli population resistant to acetolactate synthase (ALS) herbicides was collected in a maize field in north-eastern Italy and the cross-resistance pattern, resistance mechanism and fitness costs associated to mutant-resistant plants under field conditions in the presence or absence of intra-specific competition were determined. The study reports for the first time the Ala-122-Asn amino-acid change in the ALS gene that confers high levels of cross-resistance to all ALS inhibitors tested. Results of 3-year growth analysis showed that mutant resistant E. crus-galli plants had a delayed development in comparison with susceptible plants and this was registered in both competitive (3, 7, and 20 plants m -2 ) and non-competitive (spaced plants) situations. The number of panicles produced by resistant plants was also lower (about 40% fewer panicles) than susceptible plants under no-intraspecific competition. Instead, with the increasing competition level, the difference in panicle production at harvest time decreased until it became negligible at 20 plants m -2 . Evaluation of total dry biomass as well as biomass allocation in vegetative parts did not highlight any difference between resistant and susceptible plants. Instead, panicle dry weight was higher in susceptible plants indicating that they allocated more biomass than resistant ones to the reproductive organs, especially in no-competition and in competition situations at lower plant densities. The different fitness between resistant and susceptible phenotypes suggests that keeping the infestation density as low as possible can increase the reproduction success of the susceptible phenotype and therefore contribute to lowering the ratio between resistant and susceptible alleles. If adequately embedded in a

  15. A New Ala-122-Asn Amino Acid Change Confers Decreased Fitness to ALS-Resistant Echinochloa crus-galli

    Directory of Open Access Journals (Sweden)

    Silvia Panozzo

    2017-11-01

    Full Text Available Gene mutations conferring herbicide resistance may cause pleiotropic effects on plant fitness. Knowledge of these effects is important for managing the evolution of herbicide-resistant weeds. An Echinochloa crus-galli population resistant to acetolactate synthase (ALS herbicides was collected in a maize field in north-eastern Italy and the cross-resistance pattern, resistance mechanism and fitness costs associated to mutant-resistant plants under field conditions in the presence or absence of intra-specific competition were determined. The study reports for the first time the Ala-122-Asn amino-acid change in the ALS gene that confers high levels of cross-resistance to all ALS inhibitors tested. Results of 3-year growth analysis showed that mutant resistant E. crus-galli plants had a delayed development in comparison with susceptible plants and this was registered in both competitive (3, 7, and 20 plants m-2 and non-competitive (spaced plants situations. The number of panicles produced by resistant plants was also lower (about 40% fewer panicles than susceptible plants under no-intraspecific competition. Instead, with the increasing competition level, the difference in panicle production at harvest time decreased until it became negligible at 20 plants m-2. Evaluation of total dry biomass as well as biomass allocation in vegetative parts did not highlight any difference between resistant and susceptible plants. Instead, panicle dry weight was higher in susceptible plants indicating that they allocated more biomass than resistant ones to the reproductive organs, especially in no-competition and in competition situations at lower plant densities. The different fitness between resistant and susceptible phenotypes suggests that keeping the infestation density as low as possible can increase the reproduction success of the susceptible phenotype and therefore contribute to lowering the ratio between resistant and susceptible alleles. If adequately

  16. Competição entre plantas de arroz e biótipos de capim-arroz (Echinochloa spp. resistente e suscetível ao quinclorac Competition between rice plants and Echinochloa spp. biotypes resistant or susceptible to quinclorac

    Directory of Open Access Journals (Sweden)

    L. Galon

    2009-01-01

    Full Text Available Objetivou-se com este trabalho avaliar a competitividade interespecífica de biótipos de capim-arroz resistente (R e suscetível (S ao herbicida quinclorac com a cultura do arroz irrigado. O experimento foi instalado em casa de vegetação e os tratamentos consistiram em manter uma planta de arroz cv. BRS Pelota no centro da unidade experimental, variando-se na periferia as densidades de capim-arroz em: 0, 1, 2, 3, 4 ou 5 plantas do biótipo R (ITJ-13 ou S (ITJ-17 oriundos da região de Itajaí-SC. O delineamento experimental utilizado foi o completamente casualizado, em esquema fatorial 2 x 6 com quatro repetições. Aos 40 dias após a emergência, foram avaliados as massas fresca e seca e o conteúdo de água de folhas, colmos e total da parte aérea do arroz e do capim-arroz. Houve efeito significativo dos tratamentos para todas as variáveis estudadas quando a cultura do arroz foi cultivada na presença de biótipos de capim-arroz R ou S. Esse efeito foi aditivo na proporção de 1 planta m-2. Entretanto, a capacidade competitiva dos biótipos de capim-arroz resistente e suscetível ao quinclorac, com as plantas de arroz, apresentou comportamento similar quando se variou a densidade de plantas por área.This work aimed to evaluate the interspecific competitiveness of Echinochloa spp. biotypes resistant or susceptible to the herbicide quinclorac. The trial was installed under greenhouse conditions, with the biotypes resistant (ITJ-13 and susceptible (ITJ-17 to quinclorac under competition with the rice plants. The treatments consisted of maintaining one rice plant at the center of the experimental unit, surrounded by 0, 1, 2, 3, 4 or 5 Echinochloa plants, according to the treatment. The trial was arranged in a completely randomized blocks design and factorial scheme 2 x 6, with four replications. Forty days after emergence, fresh dry weights and water content of the shoots were evaluated. There was a significant effect for all the variables

  17. Disulfide-stabilized Helical Hairpin Structure and Activity of a Novel Antifungal Peptide EcAMP1 from Seeds of Barnyard Grass (Echinochloa crus-galli)*

    Science.gov (United States)

    Nolde, Svetlana B.; Vassilevski, Alexander A.; Rogozhin, Eugene A.; Barinov, Nikolay A.; Balashova, Tamara A.; Samsonova, Olga V.; Baranov, Yuri V.; Feofanov, Alexey V.; Egorov, Tsezi A.; Arseniev, Alexander S.; Grishin, Eugene V.

    2011-01-01

    This study presents purification, activity characterization, and 1H NMR study of the novel antifungal peptide EcAMP1 from kernels of barnyard grass Echinochloa crus-galli. The peptide adopts a disulfide-stabilized α-helical hairpin structure in aqueous solution and thus represents a novel fold among naturally occurring antimicrobial peptides. Micromolar concentrations of EcAMP1 were shown to inhibit growth of several fungal phytopathogens. Confocal microscopy revealed intensive EcAMP1 binding to the surface of fungal conidia followed by internalization and accumulation in the cytoplasm without disturbance of membrane integrity. Close spatial structure similarity between EcAMP1, the trypsin inhibitor VhTI from seeds of Veronica hederifolia, and some scorpion and cone snail toxins suggests natural elaboration of different functions on a common fold. PMID:21561864

  18. Disulfide-stabilized helical hairpin structure and activity of a novel antifungal peptide EcAMP1 from seeds of barnyard grass (Echinochloa crus-galli).

    Science.gov (United States)

    Nolde, Svetlana B; Vassilevski, Alexander A; Rogozhin, Eugene A; Barinov, Nikolay A; Balashova, Tamara A; Samsonova, Olga V; Baranov, Yuri V; Feofanov, Alexey V; Egorov, Tsezi A; Arseniev, Alexander S; Grishin, Eugene V

    2011-07-15

    This study presents purification, activity characterization, and (1)H NMR study of the novel antifungal peptide EcAMP1 from kernels of barnyard grass Echinochloa crus-galli. The peptide adopts a disulfide-stabilized α-helical hairpin structure in aqueous solution and thus represents a novel fold among naturally occurring antimicrobial peptides. Micromolar concentrations of EcAMP1 were shown to inhibit growth of several fungal phytopathogens. Confocal microscopy revealed intensive EcAMP1 binding to the surface of fungal conidia followed by internalization and accumulation in the cytoplasm without disturbance of membrane integrity. Close spatial structure similarity between EcAMP1, the trypsin inhibitor VhTI from seeds of Veronica hederifolia, and some scorpion and cone snail toxins suggests natural elaboration of different functions on a common fold.

  19. Competitividade de biótipos de capim-arroz resistente e suscetível ao quinclorac Competitiveness of echinochloa biotypes resistant and susceptible to quinclorac

    Directory of Open Access Journals (Sweden)

    G. Concenço

    2008-03-01

    Full Text Available Objetivou-se com este trabalho avaliar a competitividade de dois biótipos de capim-arroz, resistente e suscetível ao quinclorac, coletados em regiões orizícolas do Estado de Santa Catarina. O experimento foi instalado em ambiente protegido, e os tratamentos constaram de diferentes densidades de plantas dos biótipos de capim-arroz comprovadamente resistente (ITJ-13 e suscetível (ITJ-17 ao quinclorac, oriundos da região arrozeira de Itajaí/SC. No centro da unidade experimental, foram semeadas três sementes do biótipo de capim-arroz, considerado como o tratamento da unidade experimental. Na periferia foram semeadas dez sementes do biótipo oposto ao do tratamento (central. Dez dias após a germinação foi efetuado o desbaste, deixando-se apenas uma planta no centro da unidade experimental e um número variável de plantas do biótipo oposto, de acordo com o tratamento (0, 1, 2, 3, 4 ou 5 plantas por vaso. O delineamento experimental utilizado foi o completamente casualizado, em esquema fatorial 2 x 6, com quatro repetições. Aos 40 dias após a emergência, foram avaliados altura de plantas, número de afilhos e de folhas, área foliar, massa fresca e seca e conteúdo de água de colmos e folhas. Os dados foram analisados pelo teste F, sendo efetuado teste de Duncan para comparar o efeito de densidade de plantas e teste da Diferença Mínima Significativa (DMS para avaliar diferenças entre os biótipos resistente e suscetível, além de correlação linear simples entre as variáveis avaliadas. Nas análises, utilizou-se o nível de 5% de probabilidade. Os biótipos estudados de capim-arroz resistente e suscetível ao quinclorac são similares quando sob alta intensidade de competição, com vantagem em algumas variáveis para o biótipo suscetível sob baixa ou moderada intensidade competitiva.The objective of this research was to evaluate the competitive potential of two Echinochloa sp. biotypes, resistant and susceptible to

  20. Allelopathic Effect of Echinochloa colona L. and Cyperus iria L. Weed Extracts on the Seed Germination and Seedling Growth of Rice and Soyabean

    Directory of Open Access Journals (Sweden)

    Neha Chopra

    2017-01-01

    Full Text Available The present study was undertaken to assess the allelopathic effect of Echinochloa colona L. and Cyperus iria L. in relation to the germination and primary growth of Oryza sativa L. (rice and Glycine max L. (soyabean. Effects of dichloromethane (DCM and double distilled water soluble (DDW fractions of E. colona L. and C. iria L. root and aerial part extracts reduced germination and suppressed early seedling growth of rice and soyabean. With increase in extract concentration from 1 to 100 mg/mL, a gradual decrease in seed germination and seedling length occurred. The highest growth of G. max seedling was recorded in DDW fraction of E. colona aerial part extract at 1 mg/mL concentration with 94% germination and the lowest length was found in DCM fraction of C. iria root extract at 100 mg/mL concentration with 65% germination. In O. sativa, the highest length was noted at 1 mg/mL concentration in DDW fraction of E. colona aerial part extract with 82% germination and the lowest length was found in DCM fraction of C. iria and E. colona root extracts with germination 57% and 62%, respectively, at 100 mg/mL concentration. The results suggested that these weeds had good allelopathic potential which reduces germination and plant growth.

  1. Efecto de la profundidad y manejo de la lámina de agua en la emergencia y crecimiento de Echinochloa crus-galli.

    Directory of Open Access Journals (Sweden)

    Jorge García de la Osa

    2007-01-01

    Full Text Available En el Centro internacional Tsukuba, Japón fueron realizados ensayos en condiciones de macetas con el propósito de evaluar el efecto que producen diferentes niveles y manejos de agua sobre la emergencia y crecimiento de Echinochloa crus-galli P. Beauv. var. crus-galli. Se determinó que el aumento de la lámina de agua ejerció dos efectos sobre E. crus-galli, el retraso en el crecimiento que se manifestó de forma significativa a partir de una lámina de 5 cm y el de disminución de la cantidad de plántulas que sobresale la lámina de agua observado a partir de 10 cm. y que tomó un valor máximo con 20 cm. El establecimiento de una profundidad de agua inicial de 5 cm y posterior aumento a 10 y 15 cm cuando las plántulas de E. crus-galli alcanzaron 1-2 hojas y 2,5 cm de longitud provocaron un efecto similar sobre la emergencia y crecimiento de esta maleza que sus respectivos testigos con láminas permanentes de 10 y 15 cm. durante todo el ensayo.

  2. Quinclorac resistance induced by the suppression of the expression of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase genes in Echinochloa crus-galli var. zelayensis.

    Science.gov (United States)

    Gao, Yuan; Li, Jun; Pan, Xukun; Liu, Dingrong; Napier, Richard; Dong, Liyao

    2018-04-01

    We previously reported that the mechanism of quinclorac resistance in Echinochloa crus-galli var. zelayensis may be closely related to ethylene biosynthesis and the detoxification of cyanide. Differences in EcCAS gene sequences and expression levels may result in higher capacity to detoxify cyanide in resistant biotypes, which may avoid cyanide accumulation and avoid more ethylene and cyanide production and then avoid damage. In the present study, we focused on the mechanism of resistance related to ethylene biosynthesis in E. crus-galli var. zelayensis. The fresh weight of susceptible and moderately resistant biotypes were significantly reduced after treatment with quinclorac. However, AOA, an ethylene biosynthesis inhibitor, reduced the impact of quinclorac. On pretreatment with AOA, ethylene production was significantly reduced in the three biotypes. The highly resistant biotype produced less ethylene compared to the other two biotypes. Three ACS and seven ACO genes, which are the key genes in ethylene biosynthesis, were obtained. The expression levels of EcACS-like, EcACS7, and EcACO1 varied in the three biotypes upon treatment with quinclorac, which could be manipulated by AOA. In summary, it is inferred that the expression of EcACS-like, EcACS7, and EcACO1 can be stimulated to varying extent after quinclorac treatment in three E. crus-galli var. zelayensis biotypes, which consequently results in varying levels of ethylene production. Lower expression of these three genes results in more resistance to quinclorac, which may also be related to quinclorac resistance in E. crus-galli var. zelayensis. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Comparison of power output by rice (Oryza sativa) and an associated weed (Echinochloa glabrescens) in vascular plant bio-photovoltaic (VP-BPV) systems.

    Science.gov (United States)

    Bombelli, Paolo; Iyer, Durgaprasad Madras Rajaraman; Covshoff, Sarah; McCormick, Alistair J; Yunus, Kamran; Hibberd, Julian M; Fisher, Adrian C; Howe, Christopher J

    2013-01-01

    Vascular plant bio-photovoltaics (VP-BPV) is a recently developed technology that uses higher plants to harvest solar energy and the metabolic activity of heterotrophic microorganisms in the plant rhizosphere to generate electrical power. In the present study, electrical output and maximum power output variations were investigated in a novel VP-BPV configuration using the crop plant rice (Oryza sativa L.) or an associated weed, Echinochloa glabrescens (Munro ex Hook. f.). In order to compare directly the physiological performances of these two species in VP-BPV systems, plants were grown in the same soil and glasshouse conditions, while the bio-electrochemical systems were operated in the absence of additional energy inputs (e.g. bias potential, injection of organic substrate and/or bacterial pre-inoculum). Diurnal oscillations were clearly observed in the electrical outputs of VP-BPV systems containing the two species over an 8-day growth period. During this 8-day period, O. sativa generated charge ∼6 times faster than E. glabrescens. This greater electrogenic activity generated a total charge accumulation of 6.75 ± 0.87 Coulombs for O. sativa compared to 1.12 ± 0.16 for E. glabrescens. The average power output observed over a period of about 30 days for O. sativa was significantly higher (0.980 ± 0.059 GJ ha(-1) year(-1)) than for E. glabrescens (0.088 ± 0.008 GJ ha(-1) year(-1)). This work indicates that electrical power can be generated in both VP-BPV systems (O. sativa and E. glabrescens) when bacterial populations are self-forming. Possible reasons for the differences in power outputs between the two plant species are discussed.

  4. Desempenho do cultivar de arroz BRS pelota e controle de capim-arroz (Echinochloa spp. submetidos a quatro épocas de entrada d'água após aplicação de doses reduzidas de herbicidas Performance of rice cultivar BRS pelota and control of (Echinochloa spp. submitted to four flooding times after reduced herbicide dose application

    Directory of Open Access Journals (Sweden)

    A. Andres

    2007-12-01

    Full Text Available Este trabalho teve como objetivo avaliar a possibilidade de reduzir as doses de herbicidas na lavoura de arroz irrigado, com a supressão das plantas daninhas pela antecipação da entrada da lâmina de água, bem como avaliar o controle de capim-arroz (Echinochloa spp. em arroz irrigado, o desempenho da cultura e os efeitos dos herbicidas aplicados em pós-emergência sobre os atributos fisiológicos da cultura de arroz. O experimento foi conduzido em delineamento experimental de blocos ao acaso com parcelas subsubdivididas, com quatro repetições. As parcelas principais foram as entradas de água (A aos 5, 10, 15 e 20 dias após aplicação dos herbicidas; as subparcelas, os herbicidas (H bispyribac-sodium e bispyribac-sodium + clomazone; e as subsubparcelas, as doses de bispyribac-sodium (D de 32, 40 e 48 g ha-1 isoladas e em mistura com 300 g ha-1 de clomazone. O bispyribac-sodium foi eficiente no controle de capim-arroz, com três folhas, quando a entrada de água ocorreu até cinco dias após a aspersão e/ou até o perfilhamento do arroz irrigado, quando em mistura com clomazone. É possível trabalhar com doses inferiores à recomendada de bispyribac-sodium isoladamente, desde que a submersão seja imediata após a aplicação deste, ou até o perfilhamento quando em mistura com clomazone.The objectives of this work were to evaluate the possibility of reducing herbicide rates in flooded rice, using flooding as a tool to avoid weed emergence; to evaluate Echinochloa spp. control, culture establishment and growth and the effect of herbicides applied in pre-emergence on the physiological attributes of the rice culture. The experiment was conducted in a randomized block design with split-split plots, four floodings, two herbicides and three rates, with four replications. The plots were the floodings (A 5, 10, 15 and 20 days after herbicide application and the split plots were the herbicides (H bispyribac-sodium and bispyribac

  5. Studying of cellular interaction of hairpin-like peptide EcAMP1 from barnyard grass (Echinochloa crusgalli L.) seeds with plant pathogenic fungus Fusarium solani using microscopy techniques.

    Science.gov (United States)

    Vasilchenko, Alexey S; Yuryev, Mikhail; Ryazantsev, Dmitry Yu; Zavriev, Sergey K; Feofanov, Alexey V; Grishin, Eugene V; Rogozhin, Eugene A

    2016-11-01

    An interaction of recombinant hairpin-like cationic peptide EcAMP1 with conidia of plant pathogenic fungus Fusarium solani at the cellular level was studied by a combination of microscopic methods. EcAMP1 is from barnyard grass (Echinochloa crusgalli L.), and obtained by heterologous expression in Escherichia coli system. As a result, a direct relationship between hyphal growth inhibition and increasing active peptide concentration, time of incubation and fungal physiological condition has been determined. Dynamics of accumulation and redistribution of the peptide studied on fungal cellular cover and inside the conidia cells has been shown. The dynamics are dependent on time of coupling, as well as, a dissimilarity of EcAMP1 binding with cover of fungal conidia and its stepwise accumulation and diffuse localization in the cytoplasm. Correlation between structural disruption of fungal conidia and the presence of morphological changes has also been found. The correlation was found under the influence of peptide high concentrations at concentrations above 32 μM. The results indicate the presence of a binding of EcAMP1 with the surface of fungal conidia, thus, demonstrating a main specificity for its antifungal action at the cellular level. These results, however, cannot exclude the existence of attendant EcAMP1 action based on its intracellular localization on some specific targets. SCANNING 38:591-598, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

  6. Emergência e crescimento inicial de plantas de arroz e capim-arroz em função do nível de umidade no solo Initial emergence and growth of rice and Echinochloa sp. plants as a function of soil water level

    Directory of Open Access Journals (Sweden)

    G. Concenço

    2007-09-01

    Full Text Available Em anos de baixa precipitação durante o período pós-semeadura, as plantas de capim-arroz tendem a emergir primeiro que as de arroz, promovendo maior competição inicial com a cultura. O objetivo deste estudo foi avaliar o efeito do nível de umidade do solo, expresso em potenciais hídricos, no percentual e na velocidade de emergência, bem como no crescimento inicial de plantas de arroz e capim-arroz, em condições controladas. O experimento foi instalado em delineamento experimental de blocos casualizados, com quatro repetições. O solo utilizado foi Planossolo Hidromórfico eutrófico típico, para o qual foi previamente construída a curva de retenção de umidade. As unidades experimentais constaram de copos plásticos de 0,5 L, contendo exatamente 400 g de solo seco, e dos tratamentos dos seguintes potenciais hídricos (psiw: -0,03, -0,07, -0,1, -0,3 e -0,5 MPa, aos quais foram submetidas plantas de arroz e capim-arroz. Foi construída a curva de emergência para cada potencial hídrico e espécie; 20 dias após o início da emergência para cada espécie, três plantas de cada unidade experimental foram cortadas rente ao solo, sendo avaliados massa fresca e seca, conteúdo de água e emergência total. Plantas de capim-arroz foram mais eficientes na emergência sob potencial hídrico reduzido e menos eficientes no acúmulo de massa no início do desenvolvimento. As plantas não apresentaram estresse com potencial hídrico reduzido, e a faixa de umidade ótima para emergência do arroz foi mais estreita que para capim-arroz, situando-se ao redor de -0,07 MPa.In lower than expected rainfall years during the early post-sowing stage, Echinochloa seeds tend to germinate and emerge before rice, increasing the competition along the rice development. The objective of this work was to evaluate the effects of water level in soil, expressed as water potentials, on the emergence level and speed, as well as early growth of rice and Echinochloa

  7. Análisis de la evaluación del pasto alemán Echinochloa polystachya (H.B.K. Hicth cultivado en suelo arcilloso bajo cuatro frecuencias de corte

    Directory of Open Access Journals (Sweden)

    Manrique P. Luis Phanor

    1993-12-01

    Full Text Available

    En el experimento realizado en la hacienda Lucerna, Bugalagrande, Colombia, se utilizó un diseño de parcelas completamente al azar, con dos repeticiones para cuatro frecuencias de corte a los 21,35,49 y 63 días. La capacidad de enraizamiento varió entre 97.8 y 99.8% para los cortes realizados a los 21 y 63 días, respectivamente. La altura de las plantas aumentó en relación directa con la frecuencia de los cortes. El porcentaje de macollamiento se incrementó progresivamente con el aumento de las edades de los cortes y el porcentaje de floración se acrecentó sucesivamente para las frecuencias de 49 y 63 días. El promedio de producción de materia verde para las cuatro frecuencias de corte (8.5, 13.5, 19.5, 27.4 t/ha, presentó diferencias altamente significativas. Se presentaron diferencias estadísticas altamente significativas en materia seca (15.9, 23.1, 32.0 y 31.8 %, proteína bruta (13.0, 9.5, 7.1 y 5.2%, digestibilidad in vitro de la materia seca (61.8, 58.9, 56.6 y 54.6% y digestibilidad in vitro de la materia orgánica (64.8, 61.3, 58.5 y 57.7%.

    The main objective of this research was to study the agronomic performance and the nutritive value of German grass (Echinochloa polystachya, grown on clayed soil at Lucerna farm, located at Bugalagrande county in Cauca Valley of Colombia. The test was carried out, considering four cutting frequencies, 21,35,49 and 63 days. A complete random designed was utilized, in order to realize the statistical analysis. The analysis of rooting production capacity of the grass shows a variation of 97.8% and 99.8%, considering the cuttings done at 21 and 63 days, respectively. The plants height increase in a direct ratio to cutting frequency. On the other hand, the percent of grass clustering also increase progressively when the of cutting increase, and the percent of flowering also increase for the cutting done at 49 and 63 days. The mean production of green matter was 8.5, 13.5, 19.5 and 27

  8. Crescimento de raízes de biótipos de capim-arroz resistente e suscetível ao quinclorac em competição Root growth of Echinochloa biotypes resistant and susceptible to quinclorac under competition

    Directory of Open Access Journals (Sweden)

    L.O.B. Schuch

    2008-01-01

    Full Text Available Objetivou-se com este trabalho avaliar o potencial competitivo de biótipos de capim-arroz resistente e suscetível ao quinclorac no ambiente do solo, como forma de inferir qual deles possui maior potencial de extração de recursos. O experimento foi instalado em casa de vegetação, constando de diferentes populações de plantas dos biótipos de capim-arroz resistente (R e suscetível (S ao herbicida quinclorac, oriundos da região arrozeira de Itajaí/SC. Foi estabelecida uma planta do biótipo de capim-arroz considerado como tratamento, no centro da unidade experimental; na periferia, foram semeadas dez sementes do biótipo oposto ao do tratamento central, sendo posteriormente estabelecido o número de plantas de acordo com o tratamento (0, 1, 2, 3, 4 ou 5 plantas. O delineamento experimental foi o completamente casualizado, em esquema fatorial 2 x 6, com quatro repetições. Aos 40 DAE, foram avaliados o comprimento, volume, massa fresca, massa seca e conteúdo de água das raízes das plantas. Os dados obtidos foram submetidos à análise de variância e, em caso de significância, efetuou-se o teste de Duncan, para avaliar o efeito do aumento na população de plantas, e o teste da Diferença Mínima Significativa (DMS, para avaliar diferenças entre biótipo resistente e suscetível, além da matriz de correlação. A imposição de competição no ambiente das raízes pode afetar mais o biótipo resistente ao quinclorac que o suscetível, sendo esta característica essencial para a sobrevivência do biótipo, principalmente sob escassez do recurso.The objective of this work was to evaluate the competitive potential of Echinochloa plants resistant and susceptible to quinclorac in the soil, to evaluate whether there are potential differences in extracting nutrients from the soil. The trial was carried out under greenhouse conditions. The treatments consisted of amounts of Echinochloa plants resistant or susceptible to quinclorac. At the

  9. Growth and yield potential of Echinochloa pyramidalis (Lam.) Hitchc ...

    African Journals Online (AJOL)

    user

    Indeed, although E. pyramidalis has exhibited an excellent yielding potential in vertical-flow constructed wetlands, this treatment process faces numerous problems such as the variability of liquid waste compositions and clogging of the wetland treatment units. In Cameroon, the faecal sludge contains high organic matter ...

  10. Seed deterioration in flooded agricultural fields during winter

    Science.gov (United States)

    Nelms, C.O.; Twedt, D.J.

    1996-01-01

    We determined rate of seed deterioration for 3 crops (corn, rice, and soybean) and 8 weeds commonly found in agricultural fields and moist-soil management units in the Mississippi Alluvial Valley (MAV). The weeds were broadleaf signalgrass (Brachiaria platyphylla), junglerice barnyardgrass (Echinochloa colonum), morningglory (Ipomoea sp.), panic grass (Panicum sp.), bull paspalum (Paspalum boscianum), red rice (Oryza sativa), hemp sesbania (Sesbania exaltata), and bristlegrass (Setaria sp.). Weed seeds, except morningglory, deteriorated slower than corn and soybean, whereas rice decomposed slower than all weed seeds except red rice and bull paspalum. For land managers desiring to provide plant food for wintering waterfowl, rice is clearly the most persistent small grain crop in the MAV. Persistence of weed seeds under flooded conditions throughout winter makes them a cost-effective alternative to traditional crops on land managed for waterfowl.

  11. Fall and winter foods of northern pintails in the Sacramento Valley, California

    Science.gov (United States)

    Miller, Michael R.

    1987-01-01

    Food habits of northern pintails (Anas acuta) were investigated on 3 national wildlife refuges in the western portion of the Sacramento Valley, California, from August to March 1979-82. Pintails consumed 97% (aggregate % dry wt) plant food during diurnal foraging on national wildlife refuge rice, summer-irrigated, and summer-dry habitats from August through January. Invertebrate use increased to 28.9-65.6% of the diet in these habitats during February and March. Rice, swamp timothy (Heleochloa schoenoides), flatsedges (Cyperus spp.), common barnyardgrass (Echinochloa crusgalli), southern naiad (Najas guadalupensis), and smartweed (Polygonum spp.) seeds, miscellaneous vegetation, snails (Gastropoda), and midge (Diptera) and water beetle (Coleoptera) larvae were most important. These foods usually were taken proportional to or greater than availability. Rice was the most important food of pintails feeding nocturnally off the refuges in harvested rice fields from October through January (99.7%) and February and March (63%; barnyardgrass formed 31% of the diet). In August and October, some pintails consumed invertebrates or bulrush (Scirpus spp. ) seedlings in marshes soon after feeding in refuge rice (Aug) or harvested commercial rice fields (Oct), thereby increasing dietary protein. In late winter, females and males obtained similar (P > 0.05) percentages of invertebrates from refuge habitats. Important dietary seeds and invertebrates contained high protein or metabolizable energy content. Management should maintain adequate seed production in fall and mid-winter and invertebrate biomass in late winter.

  12. Comparative ability of northern pintails, gadwalls, and northern shovelers to metabolize foods

    Science.gov (United States)

    Miller, M.R.

    1984-01-01

    Feeding trials were used to compare the ability of northern pintails (Anas acuta), gadwalls (A. strepera), and northern shovelers (A. clypeata) to metabolize energy from a turkey starter ration, alfalfa pellets, and common barnyardgrass (Echinochloa crusgalli) seeds. No differences (P > 0.05) were detected among the three species for any of the three foods (kg body weight/day basis), for dry matter intake (DMI), body weight gain (BWG), apparent metabolizable energy (AME), or metabolized energy (MEE) on any given diet consumed in quantities large enough to promote body weight gain. The AME content of alfalfa was 57% less than the value for turkey starter and 50% less than for barnyardgrass seeds. All three species metabolized more energy and gained weight faster when fed turkey starter. Energy modeling may be facilitated if additional research verifies that all species of dabbling ducks have equal ability to obtain energy from foods available to them in the wild. Behavioral and morphological factors may be more important in defining feeding niches than digestive physiology, at least for the three duck species tested, at the time of year of the experiments, and within the limits of the quality of foods used.

  13. Optimization of foramsulfuron doses for post-emergence weed control in maize (Zea mays L.)

    Energy Technology Data Exchange (ETDEWEB)

    Pannacci, E.

    2016-11-01

    Four field experiments were carried out from 2011 to 2014 in order to evaluate the effects of foramsulfuron, applied at the recommended (60.8 g a.i./ha) and reduced doses (1/3 and 2/3), on the efficacy against several of the most important weeds in maize. For each “year-weed” combination, dose-response curves were applied to estimate the dose of foramsulfuron required to obtain 90% and 95% weed control (ED90 and ED95). Foramsulfuron phytotoxicity on maize and crop yield were assessed. Foramsulfuron at 1/3 of the recommended dose (20.3 g a.i./ha) provided 95% efficacy against redroot pigweed (Amaranthus retroflexus L.), green foxtail (Setaria viridis (L.) Beauv.), wild mustard (Sinapis arvensis L.) and black nightshade (Solanum nigrum L.). Velvetleaf (Abutilon theophrasti Medik.), common lambsquarters (Chenopodium album L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv.) were satisfactorily controlled (95% weed efficacy) with ED95 ranged from 20 to 50 g/ha of foramsulfuron (about from 1/3 to 5/6 of the recommended dose) depending on growth stage. The recommended dose was effective against pale smartweed (Polygonum lapathifolium L.) at 2-4 true leaves (12-14 BBCH scale), but this dose did not kill plants larger than 2-4 true leaves. The ranking among weed species based on their susceptibility to foramsulfuron was: redroot pigweed = green foxtail = wild mustard = black nightshade > velvetleaf = common lambsquarters = barnyardgrass > pale smartweed. Dose of foramsulfuron can be reduced below recommended dose depending on weed species and growth stage. Foramsulfuron showed a good crop selectivity and had no negative effect on maize yield. (Author)

  14. Allelopathic potential of Sapindus saponaria L. leaves in the control of weeds=Potencial alelopático de folhas de Sapindus saponaria L. no controle de plantas daninhas

    Directory of Open Access Journals (Sweden)

    Denise Garcia Santana

    2012-01-01

    Full Text Available The objective of this work was to evaluate the allelopathic potential of aqueous extracts of young and mature leaves from Sapindus saponaria on diaspore germination and seedling growth of barnyardgrass (Echinochloa crus-galli and morningglory (Ipomoea grandifolia. The aqueous extract was prepared in a proportion of 100 g of dried, ground leaves dissolved in 1000 mL of distilled water, resulting in a 10% extract concentrate. Dilutions of this concentrate were made with distilled water to 7.5, 5.0 and 2.5%. In seedling growth tests, we compared the effect of these extracts with the herbicide nicosulfuron. Both extracts of mature and young leaves caused delays and reductions in diaspore germination and seedling length of barnyardgrass and morningglory, with the most intense effects observed at a concentration of 10%. The effects of the young leaf extract were more similar to those observed with the herbicide, demonstrating that leaf maturation stage of S. saponaria affects its inhibitory effects on the growth of other plants and that this species is effective in controlling weeds.O objetivo deste trabalho foi avaliar o potencial alelopático do extrato aquoso de folhas jovens e maduras de Sapindus saponaria (sabão-de-soldado na germinação de diásporos e no crescimento de plântulas de capim-arroz (Echinochloa crus-galli e corda-de-viola (Ipomoea grandifolia. O extrato aquoso foi preparado na proporção de 100 g de folhas secas e trituradas dissolvidas em 1000 mL de água destilada, produzindo-se o extrato considerado concentrado (10%. A partir deste, foram feitas diluições em água destilada para 7,5; 5,0 e 2,5%. No teste de crescimento de plântulas comparou-se o efeito desses extratos com o herbicida nicosulfuron. Os extratos de folhas maduras e jovens causaram atraso e redução na germinação dos diásporos e no comprimento das plântulas de capim-arroz e corda-de-viola, com efeitos mais intensos na concentração de 10%. No entanto, os

  15. Integration of C4-specific ppdk gene of Echinochloa to C3 upland ...

    African Journals Online (AJOL)

    SERVER

    2008-03-18

    Mar 18, 2008 ... rice though increased photoinhibition was noted under high light intensity. Key words: Pyrurate ... PPDK is regarded as an important target in efforts to .... transgenic upland rice. The introduction of C4 photosynthetic enzyme into C3 plants was intended to improve the efficiency of solar energy utilization.

  16. Asparagus decline: Autotoxicity and autotoxic compounds in asparagus rhizomes.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Nakamura, Keisuke; Ohno, Osamu; Suenaga, Kiyotake; Okuda, Nobuyuki

    2017-06-01

    Asparagus (Asparagus officinalis L.) is a perennial vegetable, but its crop productivity and quality decrease gradually. One possible reason for "asparagus decline" is thought to be the autotoxicity of asparagus. However, the autotoxic property of asparagus rhizomes remains unknown. The objective of this study was to determine the potential role of rhizomes in the autotoxicity of asparagus. An aqueous methanol extract of asparagus rhizomes inhibited the growth of asparagus seedlings and six other test plants in a concentration-dependent manners: garden cress (Lepidum sativum L.), lettuce (Lactuca sativa L.), alfalfa (Medicago sativa L.), ryegrass (Lolium multiflorum Lam.), timothy (Phleum pratense L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv.). These results suggest that asparagus rhizomes contain autotoxic compounds. The extract was purified through several chromatographic steps with monitoring the autotoxic activity, and p-coumaric acid and iso-agatharesinol were isolated. These compounds inhibited the shoot and root growth of asparagus and two other test plants, garden cress and ryegrass, at concentrations higher than 0.1mM. The concentrations required for 50% inhibition of the root and shoot growth of these test plants ranged from 0.36 to 0.85mM and 0.41-1.22mM for p-coumaric acid and iso-agatharesinol, respectively. Therefore, these compounds may contribute to the autotoxicity caused by asparagus rhizomes and may be involved in "asparagus decline". Copyright © 2017 Elsevier GmbH. All rights reserved.

  17. Weed Control in Corn (Zea mays L. as Influenced by Preemergence Herbicides

    Directory of Open Access Journals (Sweden)

    Travis W. Janak

    2016-01-01

    Full Text Available Field studies were conducted in central and south-central Texas from 2013 through 2015 to evaluate crop tolerance and efficacy of various preemergence herbicides alone and in combination for weed control in field corn. Acetochlor and pendimethalin alone, S-metolachlor plus mesotrione, and the three-way combination of S-metolachlor plus atrazine plus mesotrione provided the most consistent control of annual grasses including browntop panicum (Panicum fasciculatum L., Texas millet (Urochloa texana L., barnyardgrass (Echinochloa crus-galli L., and sprawling signalgrass (Brachiaria reptans L.. Palmer amaranth [Amaranthus palmeri (S. Wats.] control was at least 90% with fluthiacet-methyl plus pyroxasulfone, atrazine plus either acetochlor, alachlor, dimethenamid-P, S-metolachlor, or S-metolachlor plus mesotrione, saflufenacil plus dimethenamid-P, and S-metolachlor plus mesotrione. Hophornbeam copperleaf (Acalypha ostryifolia L. was difficult to control; however, acetochlor, saflufenacil or pyroxasulfone alone, saflufenacil plus dimethenamid-P, and S-metolachlor plus mesotrione provided at least 90% control. Acetochlor or saflufenacil alone, thiencarbazone-methyl plus isoxaflutole, dimethenamid-P plus atrazine, rimsulfuron plus mesotrione, and saflufenacil plus dimethenamid-P controlled common sunflower (Helianthus annuus L. at least 90%. Corn injury was minimal (≤3% with all herbicides. In general, corn grain yield was greatest with herbicide treatments containing more than one active ingredient compared with a single active ingredient.

  18. Flavonoid glycosides from leaves and straw of Oryza sativa and their effects of cytotoxicity on a macrophage cell line and allelopathic on weed germination

    Directory of Open Access Journals (Sweden)

    Ill-Min Chung

    2018-03-01

    Full Text Available Five new flavonoids namely, 5-hydroxy-6-isoprenyl-7,4′-dimethoxyflavonol-3-O-β-d-arabinofuranoside (1, 5,7-dihydroxy-4′-methoxyflavone-7-O-β-d-arabinopyranosyl-2′′-n-decan-1′′′-oate (2, 3-butanoyl-5,6,8-trihydroxy-7,4′-dimethoxyflavonol--5-O-β-d-glucopyranoside (3, 7, 4′-dimethoxy-5-hydroxyflavone-5-O-α-d-arabinopyranosyl-(2′′ → 1′′′-O-α-d-arabinopyranoside (4, and 5,6-dihydroxy-7, 4′-dimethoxyflavone-5-O-α-d-glucopyranoside (5, together with two known compounds, were isolated from the methanol extract of Oryza sativa leaves and straw. Their structures of new compounds were elucidated by 1D and 2D NMR spectral methods, viz: COSY, HMBC and HSQC aided by mass techniques and IR spectroscopy. The cytotoxicity of these compounds (1–7 were assessed by using (RAW 264.7 mouse macrophages cell line, and allelopathic effects of compounds (1–7 on the germination characteristics of barnyardgrass (Echinochloa oryzicola and pigweed (Chenopodium album L. were also evaluated. The compounds 1, 6 and 7 showed cytotoxicity and compounds 1–7 exhibited significant inhibitory activity on the seed germination of two weed species.

  19. Comparative actions of clomazone on beta-carotene levels and growth in rice (Oryza sativa) and watergrasses (Echinochloa spp).

    Science.gov (United States)

    TenBrook, Patti L; Tjeerdema, Ronald S

    2005-06-01

    Seedlings of rice, early watergrass (thiobencarb-resistant and thiobencarb-susceptible biotypes, R and S, respectively), and late watergrass (thiobencarb-resistant and thiobencarb-susceptible biotypes, R and S, respectively) were hydroponically exposed to clomazone at concentrations ranging from 0.08 to 7.9 microM. Whole-plant growth (mg fresh wt) and beta-carotene concentrations (microg g(-1) fresh wt) were measured after a 7-day exposure period. For growth, the no observed effect concentrations (NOECs) were 7.9, 0.21, 0.21, 0.46 and 0.46 microM clomazone for rice, early watergrass (R), early watergrass (S), late watergrass (R) and late watergrass (S), respectively, while the concentrations causing 25% inhibition in response (IC25) were 5.6 (+/-1.6), 0.46 (+/-0.06), 0.42 (+/-0.08), 0.92 (+/-0.45) and 0.79 (+/-0.08) microM clomazone, respectively. Clomazone inhibits beta-carotene synthesis via inhibition of the non-mevalonate isoprenoid synthetic pathway. For assessment of clomazone effects, beta-carotene levels proved to be a more sensitive toxicological endpoint than growth. For rice, early watergrass (R), early watergrass (S), late watergrass (R) and late watergrass (S), the beta-carotene NOECs were 0.21, <0.08, <0.08, 0.08 and 0.46 microM clomazone respectively, while IC25 values were 0.42 (+/-0.26), 0.08 (+/-0.02), 0.08 (+/-0.02), 0.33 (+/-0.09) and 0.54 (+/-0.15) microM, respectively. No evidence was found that the thiobencarb-resistance mechanisms present in early and late watergrasses impart resistance to clomazone. Due to similar sensitivity between rice and late watergrass, use of clomazone in rice culture will require the use of a safening technique.

  20. Effect of Serjania lethalis ethanolic extract on weed control Efeito do extrato etanólico de Serjania lethalis no controle de plantas daninhas

    Directory of Open Access Journals (Sweden)

    P.U. Grisi

    2013-06-01

    Full Text Available The objective of this study was to evaluate the effect of the ethanolic extract of Serjania lethalis leaves and stems on the diaspore germination and seedling growth of wild poinsettia (Euphorbia heterophylla and barnyardgrass (Echinochloa crus-galli. The crude ethanolic extract was prepared from 100 g of dry plant material dissolved in 500 ml of ethanol. The extracts were solubilized in a buffer solution containing dimethyl sulfoxide (DMSO at concentrations of 10.0, 7.5, 5.0 and 2.5 mg mL-1. The effect of these extracts was compared with herbicide oxyfluorfen in bioassays. The ethanolic extracts of S. lethalis leaves and stems inhibited the germination and seedling growth of barnyardgrass and wild poinsettia in a concentration-dependent manner. The reduction in the root length of E. heterophylla seedlings might be attributed to the reduced elongation of metaxylem cells. The phytotoxicity of the extracts ranged according to the receptor species, and for some variables, the inhibitory effect was similar, and even superior, to that of the commercial herbicide. Thus, S. lethalis extracts might be a promising alternative for sustainable weed management.O objetivo deste estudo foi avaliar o efeito do extrato etanólico de folhas e caules de Serjania lethalis sobre a germinação dos diásporos e crescimento de plântulas de amendoim-bravo (Euphorbia heterophylla e capim-arroz (Echinochloa crus-galli. O extrato bruto etanólico foi preparado na proporção de 100 g de material vegetal seco para 500 mL de etanol. A partir deste, os extratos foram solubilizados em solução tampão e dimetil sulfóxido (DMSO nas concentrações 10,0, 7,5, 5,0 e 2,5 mg mL-1. Nos bioensaios comparou-se o efeito desses extratos com o herbicida oxyfluorfen. Os extratos etanólicos de folhas e caules de S. lethalisexerceram atividade inibitória no processo de germinação e no crescimento das plântulas de capim-arroz e amendoim-bravo, com efeito dependente da concentra

  1. Weed Suppressing Potential and Isolation of Potent Plant Growth Inhibitors from Castanea crenata Sieb. et Zucc

    Directory of Open Access Journals (Sweden)

    Phung Thi Tuyen

    2018-02-01

    Full Text Available This study isolated, determined, and quantified plant growth inhibitors in Japanese chestnut (Castanea crenata Sieb. et Zucc, a deciduous species native to Japan and Korea. In laboratory assays, C. crenata leaves showed strong inhibition on germination and seedling growth of Echinochloa crus-galli (barnyardgrass, Lactuca sativa (lettuce, and Raphanus sativus (radish. Laboratory and greenhouse trials showed that leaves of C. crenata appeared as a promising material to manage weeds, especially the dicot weeds. By GC-MS and HPLC analyses, gallic, protocatechuic, p-hydroxybenzoic, caffeic, ferulic, ellagic, and cinnamic acids were identified and quantified, of which ellagic acid was present in the highest quantity (2.36 mg/g dried leaves. By column chromatography and spectral data (1H- and 13C-NMR, IR, and LC-MS analysis, a compound identified as 2α,3β,7β,23-tetrahydroxyurs-12-ene-28-oic acid (1 was purified from the methanolic leaf extract of C. crenata (0.93 mg/g dried leaves. This constituent showed potent inhibition on growth of E. crus-galli, a problematic weed in agricultural practice. The inhibition of the compound 1 (IC50 = 2.62 and 0.41 mM was >5 fold greater than that of p-hydroxybenzoic acid (IC50 = 15.33 and 2.11 mM on shoot and root growth of E. crus-galli, respectively. Results suggest that the isolated the compound 1 has potential to develop natural herbicides to manage E. crus-galli. This study is the first to isolate and identify 2α,3β,7β,23-tetrahydroxyurs-12-ene-28-oic acid in a plant and report its plant growth inhibitory potential.

  2. Weed Suppressing Potential and Isolation of Potent Plant Growth Inhibitors from Castanea crenata Sieb. et Zucc.

    Science.gov (United States)

    Tuyen, Phung Thi; Xuan, Tran Dang; Tu Anh, Truong Thi; Mai Van, Truong; Ahmad, Ateeque; Elzaawely, Abdelnaser Abdelghany; Khanh, Tran Dang

    2018-02-07

    This study isolated, determined, and quantified plant growth inhibitors in Japanese chestnut ( Castanea crenata Sieb. et Zucc), a deciduous species native to Japan and Korea. In laboratory assays, C. crenata leaves showed strong inhibition on germination and seedling growth of Echinochloa crus-galli (barnyardgrass), Lactuca sativa (lettuce), and Raphanus sativus (radish). Laboratory and greenhouse trials showed that leaves of C. crenata appeared as a promising material to manage weeds, especially the dicot weeds. By GC-MS and HPLC analyses, gallic, protocatechuic, p -hydroxybenzoic, caffeic, ferulic, ellagic, and cinnamic acids were identified and quantified, of which ellagic acid was present in the highest quantity (2.36 mg/g dried leaves). By column chromatography and spectral data (¹H- and 13 C-NMR, IR, and LC-MS) analysis, a compound identified as 2α,3β,7β,23-tetrahydroxyurs-12-ene-28-oic acid ( 1 ) was purified from the methanolic leaf extract of C. crenata (0.93 mg/g dried leaves). This constituent showed potent inhibition on growth of E. crus-galli , a problematic weed in agricultural practice. The inhibition of the compound 1 (IC 50 = 2.62 and 0.41 mM) was >5 fold greater than that of p -hydroxybenzoic acid (IC 50 = 15.33 and 2.11 mM) on shoot and root growth of E. crus-galli , respectively. Results suggest that the isolated the compound 1 has potential to develop natural herbicides to manage E. crus-galli . This study is the first to isolate and identify 2α,3β,7β,23-tetrahydroxyurs-12-ene-28-oic acid in a plant and report its plant growth inhibitory potential.

  3. Determining the Optimum Concentration of Pretilachlor and Sunrice plus Herbicides for Weed control in Rice

    Directory of Open Access Journals (Sweden)

    A. Ebrahimpour Lish

    2017-02-01

    Full Text Available In order to determine the optimal rates of Pertilachlor and Sunrice­-plus herbicides for weed control of rice (Oryza sativa Var.Tarom Hashemi, a factorial experiment was conducted with a randomized complete block design with four replications in Rice Research Farm of Faculty of Agriculture, University of Guilan, Rasht, northern Iran. The first factor was weed control treatment which   consisted of lower than, equal, and more than recommended levels of Pertilachlor (i.e. 0.5, 0.75, 1 kg a.i ha-1 and Sun­rice plus (0.45, 0.9, 1.35 kg a.i ha-1 herbicides, along with unweeded and twice hand-weeded controls. The second factor consisted of two levels of nitrogen fertilizer (N application (i.e. 0 and 90 kg ha-1 of N. Barnyardgrass (Echinochloa crus-galli L. and Purple nutsedge (Cyperus rotandus L. were the most dominant weeds of the experimental plots. The highest number of filled panicles per plant, number of grains per panicle, and grain yield were found in recommended rate of Pertilachlor, Sun­rice plus and more than recommended rate of Sun­rice plus due to adequate weed control (>70% at the presence of 90 kg ha-1 of N. The lowest number of grains per panicle, number of panicles per plant and grain yield were observed in unweeded treatment, at both levels of nitrogen fertilizer application.  It was concluded that application of N is effective in increasing grain yield of the examined rice genotype only if weeds are effectively controlled by herbicides. Hence, application of N in the unweeded conditions does not lead to an increase in grain yield of rice, because the consumption of N by weeds decreased the effect of nitrogen on rice grain production.

  4. Path Analysis of Rice (Oryza sativa L. Grain Yield and its Related Components in Competition with Barnyard Grass [Echinochloa crus-galli (L. P. Beauv.

    Directory of Open Access Journals (Sweden)

    H. Aminpanah

    2013-10-01

    Full Text Available One component of integrated weed management is use of cultivars with high competitive ability against weeds. Balance between competitiveness and productivity of rice under condition of presence or absence of weeds, is complicated the breeding of rice cultivars to increase competitiveness against weeds. Path coefficient analysis has been widely used in crop breeding to determine the nature of relationships between the grain yield (GY and its contributing components. To study the weed-suppressive ability by rice, an experimental was conducted in a randomized complete block design with four replications in Chprsr, Tonekabon Rice Research Station at 2009. The experimental treatments include seven varieties (Daylamani, Khazar, Sepeedrud, Neamat, Dorfak, Fajr and Shiroodi and three lines (830, 841 and 843 of rice that were cultured in the presence of barnyard grass. The results of path analysis showed ability withstands competition (AWC, thousand grain weight (THGW, fertile tiller number m-2 (FT, filled grain number panicle-1 (FG and competitive index (CI as the first-order variables for GY. The traits such as specific leaf area of rice at 25 days after transplanting (Rsla25, ear length (EL, Filled grain percentage (FGP, specific leaf area of rice at heading stage (RslaHD were as the second-order variables for GY and influenced positively this response variable. Dry weight of barnyard grass biomass was negatively correlated with CI and RslaHD. However, these traits have a positive effect on grain yield, but fertile tiller number and specific leaf area at heading stage are measurable before maturity of grain. Thus, select of cultivar with high grain yield is possible before heading of grain, through these two traits. The variety of Shiroodi and line of 843 with highest value of specific leaf area at 25 days after transplanting and heading stage, high ability withstands competition and competitive index have a high capacity to compete with barnyard grass and can be considered as a suitable cultivar in selection processes and are also used as crosses parents.

  5. A large-scale field study of transgene flow from cultivated rice (Oryza sativa) to common wild rice (O. rufipogon) and barnyard grass (Echinochloa crusgalli).

    Science.gov (United States)

    Wang, Feng; Yuan, Qian-Hua; Shi, Lei; Qian, Qian; Liu, Wu-Ge; Kuang, Ba-Geng; Zeng, Da-Li; Liao, Yi-Long; Cao, Bin; Jia, Shi-Rong

    2006-11-01

    The introgression of transgenes into wild relatives or weeds through pollen-mediated gene flow is a major concern in environmental risk assessment of transgenic crops. A large-scale (1.3-1.8 ha) rice gene flow study was conducted using transgenic rice containing the bar gene as a pollen donor and Oryza rufipogon as a recipient. There was a high frequency of transgene flow (11%-18%) at 0-1 m, with a steep decline with increasing distance to a detection limit of 0.01% by 250 m. To our knowledge, this is the highest frequency and longest distance of gene flow from transgenic rice to O. rufipogon reported so far. On the basis of these data, an adequate isolation distance from both conventional and transgenic rice should be taken for in situ conservation of common wild rice. Meanwhile, there is no evidence of transgene introgression into barnyard grass, even when it has coexisted with transgenic rice containing the bar gene for five successive years. Thus, the environmental risk of gene flow to this weedy species is of little concern.

  6. Effect of enzymatic hydrolysis of starch on pasting, rheological and viscoelastic properties of milk-barnyard millet (Echinochloa frumentacea) blends meant for spray drying.

    Science.gov (United States)

    Kumar, P Arun; Pushpadass, Heartwin A; Franklin, Magdaline Eljeeva Emerald; Simha, H V Vikram; Nath, B Surendra

    2016-10-01

    The influence of enzymatic hydrolysis of starch on the pasting properties of barnyard millet was studied using a rheometer. The effects of blending hydrolyzed barnyard millet wort with milk at different ratios (0:1, 1:1, 1:1.5 and 1:2) on flow and viscoelastic behavior were investigated. From the pasting curves, it was evident that enzymatically-hydrolyzed starch did not exhibit typical pasting characteristics expected of normal starch. The Herschel-Bulkley model fitted well to the flow behaviour data, with coefficient of determination (R(2)) ranging from 0.942 to 0.988. All milk-wort blends demonstrated varying degree of shear thinning with flow behavior index (n) ranging from 0.252 to 0.647. Stress-strain data revealed that 1:1 blend of milk to wort had the highest storage modulus (7.09-20.06Pa) and an elastically-dominant behavior (phase angle <45°) over the tested frequency range. The crossover point of G' and G" shifted to higher frequencies with increasing wort content. From the flow and viscoelastic behavior, it was concluded that the 1:1 blend of milk to wort would have least phase separation and better flowability during spray drying. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Allelopathic activities of Jasminum officinale f. var. grandiflorum ...

    African Journals Online (AJOL)

    Allelopathic activities of Jasminum officinale f. var. grandiflorum (Linn.) Kob.: Inhibition effects on germination, seed imbibition, and α-amylase activity induction of Echinochloa crus-galli (L.) Beauv.

  8. Removal of faecal bacteria and nutrients from domestic wastewater ...

    African Journals Online (AJOL)

    The aim of this study was to evaluate the removal of faecal bacteria and nutrients from domestic wastewater, in surface flow wetlands vegetated with Echinochloa pyramidalis. Horizontal surface flow (HSF) wetlands were fed with primarily treated domestic wastewater at organic loading rates varying from 20.74 to 27.15 g ...

  9. Interference of five problematic weed species with rice growth and ...

    African Journals Online (AJOL)

    Five weed species namely, Cyperus rotundus L., Cyperus difformis L., Echinochloa colonum (L.) Link., Paspalum paspaloides (Mich.) Scribner, and Marsilea minuta L. were selected for the assessment of their level of competition with two commonly grown rice varieties viz. Basmati-385 and Super Basmati. Root and shoot ...

  10. Allelopathic activities of Jasminum officinale f. var. grandiflorum ...

    African Journals Online (AJOL)

    A methanolic extract in wettable powder from the leaves of Jasminum officinale f. var. grandiflorum (Linn.) Kob. (JWP) was inhibitory to germination and seedling growth of Echinochloa crus-galli (L.) Beauv. weeds. The inhibition percentages on E. crus-galli seed germination treated with 500 to 8,000 ppm for 7 days was ...

  11. Quantitative Trait Loci Analysis of Allelopathy in Rice

    DEFF Research Database (Denmark)

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

    2008-01-01

    The allelopathic potential of rice (Oryza sativa L.) against Echinochloa crus-galli (L.) Beauv. was investigated under both laboratory and greenhouse conditions. A population of 150 recombinant inbred lines (RILs) was derived through single-seed descent from a cross between the indica cultivar AC...

  12. Allelopathic potential of selected rice varieties | Karim | African ...

    African Journals Online (AJOL)

    Average percent inhibition (API) in lettuce due to allelopathic effect of different rice varieties/lines was estimated. Under greenhouse conditions, double-pot technique was followed using barnyard grass (Echinochloa crusgalli L.) as indicator plant. The changes in barnyard grass plant charcters due to allelopathic effect of ...

  13. Moist-Soil Impoundments for Wetland Wildlife.

    Science.gov (United States)

    1999-10-01

    Digitaria spp. Aster Aster spp. Cultivated rice Oryza sativa Barnyard grass Echinochloa crusgalli var. mitis Curltop ladysthumb Polygonum...Long-term pump costs will vary according to fuel prices, repair and maintenance, and spe- cific situations; however, long-term cost assessment

  14. 7 CFR 868.202 - Definition of other terms.

    Science.gov (United States)

    2010-01-01

    ... Rice Classes shall be based on the percentage of whole kernels, large broken kernels, and types of rice... which, after milling to a well-milled degree, contains more than 10 percent of “other types” as defined...-milled degree. (g) Objectionable seeds. Seeds other than rice, except seeds of Echinochloa crusgalli...

  15. Macrophyte community development and its implication for fisheries ...

    African Journals Online (AJOL)

    Agricultural activities, and poor management practices over the years have led to high siltation rates and consequent extensive growth of emergent aquatic macrophytes such as Typha australis, Nymphaea lotus, Echinochloa pyramidalis and Leersia hexandra, as well as marginal plants such as Mimosa pigra and Sesbania ...

  16. Rice field flora and vegetation in the provinces of Valencia and Tarragona

    Directory of Open Access Journals (Sweden)

    Carretero, J. L.

    1988-01-01

    Full Text Available Twenty nine emergent and twenty floating or submerged taxa , were found in the rice fields in Valencia and Tarragona provinces. Eleven of the se taxa, all them emergent, are alien Of introduced ones. Echinochloa oryzoides and E. oryzicola are the most important in both areas, together with Cyperus difformis and Echinochloa hispidula in Valencia. The remaining thirty eight taxa belong to the native flora. There are predominantly the emergent Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli and Paspalum distichum; the floating Lemna minor and L. gibba; the submersed Potamogeton nodosus; Zannichellia palustris and Najas minor; and the macroscopical algae Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme, Spirogyra spp., Pithophora oedogania and Hydrodictyon reticulatum. The flora evolution during the last years is analyzed and the present weed communities are studied. The contribution of the different phytosociological classes to the rice field weed flora is presented.

    De los 49 táxones registrados (29 emergentes y 20 flotantes o sumergidos 11 son exóticos introducidos, de los cuales los más importantes son Echinochloa oryzoides y E. oryzicolaen ambas zonas, además de Cyperus difformis y Echinochloa hispidula en Valencia, y el resto propios de la flora autóctona, predominando Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli y Paspalum distichum como emergentes, Lemna minor y L. gibba como flotantes, Potamogeton nodosus, Zannichellia palustris y Najas minor como sumergidos y Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme. Spirogyra spp., Pirhophora oedogonia e Hydrodictyon reticulatum como algas macroscópicas. Se analiza la evolución experimentada por la flora en los últimos años, además de estudiar las

  17. The Newly Isolated Endophytic Fungus Paraconiothyrium sp. LK1 Produces Ascotoxin

    Directory of Open Access Journals (Sweden)

    Sang-Mo Kang

    2012-01-01

    Full Text Available We have isolated five endophytic fungi from the roots of Capsicum annuum, Cucumis sativus and Glycine max. The culture filtrates (CF of these endophytes were screened on dwarf mutant rice (Waito-C and normal rice (Dongjin-byeo. Endophyte CAC-1A significantly inhibited the growth of Waito-C and Dongjin-byeo. Endophyte CAC-1A was identified as Paraconiothyrium sp. by sequencing the ITS rDNA region and phylogenetic analysis. The ethyl acetate fraction of Paraconiothyrium sp. suppressed the germination of Lactuca sativa and Echinochloa crus-galli seeds. The ethyl acetate fraction of the endophyte was subjected to bioassay-guided isolation and we obtained the phytotoxic compound ascotoxin (1 which was characterized through NMR and GC/MS techniques. Ascotoxin revealed 100% inhibitory effects on seed germination of Echinochloa crus-galli. Compound (1 was isolated for the first time from Paraconiothyrium sp.

  18. Macrophytes aquatiques dans les eaux "continentales" ivoiriennes

    OpenAIRE

    N'dah, E.; Arfi, Robert

    1996-01-01

    Inventory and socio-economic impacts of water weed are presented. Free-floating species (Eichhornia crassipes, Pistia strationes) floating leaves plants (Nymphaea lotus, Polygonum senegalense) as well as emerged species such as Echinochloa pyramidalis and Nelumbo nucifera are the most common species in the concerned aquatic environments. These plants have been colonizing these environments for about a decade and the colonized area are equivalent to 70 % of the whole of the water surface. Besi...

  19. Preliminary study of the aquatic macrophytes of selected fish ponds and reservoirs in Makurdi, Benue State, Nigeria

    OpenAIRE

    Okayi, R.G.; Abe, O.M.

    2003-01-01

    A five months survey was conducted to identify the aquatic macrophytes in fishponds and reservoirs in Makurdi (Benue State, Nigeria) between August and December 1999. A total of 3-prominent aquatic macrophytes were identified: Ipomoea aquatica, Nymphae lotus and Echinochloa pyramidalis at two-study sites (site 1, receives organic manure effluent from a cattle ranch, site 2, receives inorganic fertilizer through application). Ipomoea aquatica were found restricted to site l, while Nymphae lotu...

  20. Phytotoxic Activity of Stem Bark and Leaves of Blepharocalyx salicifolius (Myrtaceae on Weeds

    Directory of Open Access Journals (Sweden)

    Eduardo HABERMANN

    2015-01-01

    En este estudio se evaluó la fitotoxicidad de los extractos y fracciones de las cortezas del tallo (suber y de las hojas maduras de Blepharocalyx salicifolius Kuth O. Berg sobre el crecimiento inicial de Echinochloa crus- galli L. P. Beauv. (capim-arroz y Euphorbia heterophylla L. (amendoim-bravo. Estos extractos fueron obtenidos por extracción exhaustiva y fraccionamiento por coeficiente de partición con disolventes o

  1. Distribución e identificación de especies hospedantes de Heterodera glycines Ichinohe raza 3 en el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Varón de Agudelo Francia

    1988-06-01

    Full Text Available Se dividió la parte plana del Valle del Cauca en tres zonas (norte, centro y sur, habiéndose visitado 33 fincas. En la zona norte las malezas con mayor porcentaje de frecuencia y distribución en los cultivos de soya fueron Digitaria horizontalis, Echinochloa colonum y Leptochloa filiformis; en la zona centro Ipomoea hirta, Amaranthus dubius y Echinochloa colonum y en la zona sur predominaron Ipomoea hirta, Portulaca oleracea Cyperus rotundus. Los análisis de muestras de suelo y raíces indicaron que H. glycines se encuentra distribuido en todo el Valle del Cauca, presentando la zona sur (Candelaria, Palmira y Puerto Tejada las mayores poblaciones. Entre las especies evaluadas (malezas, cultivos, leguminosas forrajeras y silvestres, solamente Glycine max y Phaseolus vulgaris se consideraron como susceptibles a H. glycines raza 3. y P. angularis y P. multiflora permitieron muy poca infección y multiplicación del nemátodo.A nematode recognition of Heterodera glycines was focused on crops of soybean. Valle del Cauca was divided in three zones (northen, central and southern and 33 farms were visited. The results of the analysis on samples of soils and roots showe that Heterodera glycines is scattered throughout Valle del Cauca, being the southern zone (Palmira, Candelaria and Puerto Tejada the one having the highest standards in nematode population. Weeds showing a greater frequency percentage were : Digitaria horizontalis, Echinochloa colonum and Leptochloa filiformis, in the northen zone; Ipomoea hirta, Amaranthus dubius and Echinochloa colonum, in the central zone, and Ipomoea hirta, Portulaca oleracea and Cyperus rotundus, in the southern zone , From among the whole species evaluated (weeds, crops, leguminous a n d fodder plants, Glycine max and Phaseolus vulgaris were considered to be susceptible to H. Glycines race 3. Phaseolus angularis y P. multiflora let low population levels.

  2. Changes in weed infestations on plantations of sugar beet (Beta vulgaris L. subsp. vulgaris cultivated on black soil near Wrocław in 1989–1995 and 2006–2012

    Directory of Open Access Journals (Sweden)

    Krzysztof Domaradzki

    2016-03-01

    Full Text Available Field studies were carried out in 1989–1995 and 2006–2012 on plantations of sugar beet (Beta vulgaris L. subsp. vulgaris. During this period, 542 phytosociological relevés were made using the Braun-Blanquet method. In total, 46 weed species were found. In 1989–1995, the occurrence of 36 segetal species was reported. The highest cover indices were determined for Chenopodium album and Amaranthus retroflexus. Galium aparine, Echinochloa crus-galli, and Elymus repens were the dominant species, as well. Analysis of the frequency of occurrence revealed one constant species (Chenopodium album, two frequent species (Amaranthus retroflexus and Galium aparine, and two medium-frequent species (Echinochloa crus-galli and Matricaria maritima ssp. inodora. In 2006–2012, the occurrence of 40 weed species on the sugar beet plantations was recorded. The plantations were clearly dominated by Chenopodium album, accompanied by Polygonum persicaria and Polygonum lapathifolium ssp. lapathifolium. Other dominant species comprised Setaria viridis, Galinsoga parviflora, Brassica napus ssp. napus, and Fallopia convolvulus. The Chenopodium album was a constant component of the sugar beet plantations. In turn, no frequent species were observed and six medium-frequent species were found (Setaria viridis, Galinsoga parviflora, Brassica napus ssp. napus, Echinochloa crus-galli, Amaranthus retroflexus, and Capsella bursa-pastoris. Noteworthy, the presence of previously unreported species, e.g., Abutilon theophrasti, Hyoscyamus niger, or Artemisia vulgaris, was revealed. These species are rare components in sugar beet crops. A reverse phenomenon, i.e., the disappearance of some species such as Euphorbia helioscopia, Malva neglecta, Rumex acetosella, Sinapis arvensis, or Sisymbrium officinale, was also observed.

  3. EFFECTIVENESS OF SOME POST-EMERGENCE HERBICIDES IN SOYBEAN

    OpenAIRE

    Knežević, Mira; Antunović, Manda; Ranogajec, Ljubica; Baličević, Renata

    2008-01-01

    A three-year field experiment was conducted in soybean on lessive pseudogley soil at Čačinci locality (P.P. Orahovica d.d.) in North-eastern Croatia to evaluate the effectiveness of chemical weed control through single or multiple applications of post-emergence herbicides, alone or in combinations and their effects on soybean yields. Main weeds were summer annual species of Echinochloa crus-galli (140 - 269 shoots/m2), Ambrosia artemisiifolia (8-56 plants/m2) and Chenopodium album (3-12 plant...

  4. Differences in the Anaerobic Lactate-Succinate Production and in the Changes of Cell Sap pH for Plants with High and Low Resistance to Anoxia.

    Science.gov (United States)

    Menegus, F; Cattaruzza, L; Chersi, A; Fronza, G

    1989-05-01

    Anaerobically treated seedlings of Oryza sativa L. var arborio accumulated in their shoots more succinate than lactate and cell sap became alkaline. Conversely, in Triticum aestivum L. var MEK 86 lactate accumulation was far higher than that of succinate and cell sap was acidified. Anoxia clearly induced proton consumption in both species as an important means to prevent or counteract acidosis. Other species studied were: Echinochloa crus-galli L. Beauv., Zea mays L. var De Kalb XL75, Secale cereale L. var primizia and Hordeum vulgare L. var rondo. Changes in cell sap pH and succinate to lactate ratios distinguished resistant from nonresistant species.

  5. Características micromorfológicas de biótipos de capim‑arroz resistente e suscetível ao quinclorac

    OpenAIRE

    Ferreira,Evander Alves; Concenço,Germani; Galon,Leandro; Delgado,Marina Neves; Aspiazú,Ignacio; Silva,Alexandre Ferreira da; Ferreira,Francisco Affonso; Meira,Renata Maria Strozi Alves

    2012-01-01

    O objetivo deste trabalho foi avaliar o efeito do quinclorac nas características anatômicas de folhas e raízes de biótipos de capim‑arroz (Echinochloa spp.), resistente e suscetível a este herbicida, por meio de avaliações micromorfométricas. As plantas foram cultivadas em vasos de plástico com capacidade de 250 cm³. As imagens dos cortes foram obtidas com microscópio de luz equipado com sistema U‑Photo, acoplado à câmera digital conectada a microcomputador. Na seção transversal d...

  6. IDENTIFIKASI TUMBUHAN SUKU POACEAE SEBAGAI SUPLEMEN MATAKULIAH KEANEKARAGAMAN TUMBUHAN

    Directory of Open Access Journals (Sweden)

    Desy Yanuarita Wulandari

    2017-01-01

    Full Text Available Poaceae known as plants used as food ingredients in Indonesian. One area thas has high level diversity of plants Poaceae is Tahura R. Soerjo. Morphological characterization Poaceae in that region are still rare. The Goal for this research are to identify Poaceae tribes, and make photography Poaceae data that can be used as a supplement on Diversity of Plants course. This study included descriptive exploratory study with free cruising method. The species Poaceae has identified are Bambusa multiplex, Dendrocalamus asper, Digitaria radicosa, Echinochloa sp, Eragrostis unioloides, Lophatherum gracile, Oplismenus burmanni, Paspalidium flavidum, Pennisetum alopecuroides, Phragmites karka, Setaria parviflor. Suku Poaceae dikenal sebagai tumbuhan yang dimanfaatkan sebagai bahan pangan masyarakat Indonesia. Salah satu daerah yang memiliki tingkat keanekaragaman tumbuhan Poaceae adalah di Tahura R. Soerjo. Karakterisasi morfologi terkait suku Poaceae di daerah tersebut masih sedikit. Tujuan dalam penelitian ini adalah untuk identifikasi suku Poaceae, membuat data fotografi suku Poaceae sehingga dapat digunakan sebagai suplemen keanekaragaman tumbuhan. Penelitian ini termasuk penelitian deskriptif eksploratif dengan metode jelajah bebas. Sebelas spesies suku Poaceae yang telah teridentifikasi, yaitu Bambusa multiplex, Dendrocalamus asper, Digitaria radicosa, Echinochloa sp, Eragrostis unioloides, Lophatherum gracile, Oplismenus burmanni, Paspalidium flavidum, Pennisetum alopecuroides, Phragmites karka, Setaria parviflora.

  7. Fruiting phenology of some weed species in sowing of chosen cultivar plants

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    Marian Wesołowski

    2012-12-01

    Full Text Available In the paper, the percentage shares of the phases of fruiting and diaspore shedding of some weed species during fodder beet, spring wheat and faba bean harvest are presented. The results of the study were gathered in the years 2000-2003 on river alluvial soil made from light loam. The experimental scheme included mechanical and chemical control of the cultivated plants. On weed-free objects treated with herbicides, the following herbicides were used: fodder beet - Buracyl 80 WP (lenacyl 80% in dose 1 kg.ha-1; spring wheat - Chwastox Turbo 340 SL (MCPA + dicamba in dose 2l.ha-1; faba-bean - Afalon (linuron 50% in dose 1,5 kg.ha-1. Phenological observations were carried out at 10-day intervals beginning from the day of sowing the cultivated plant. It was proven that weeds had the most favourable conditions of fruiting and seed shedding in fodder beet and faba bean. Fruiting and shedding of most weed species were limited by herbicides, as well as cold years. The following weed species: fodder beet without herbicides - Lamium amplexicaule, Chenopodium polyspermum, Anagallis arvensis i Echinochloa crus-galli; fodder beet with herbicides - Convolvulus arvensis, Lamium purpureum i Echinochloa crus-galli; spring wheat without herbicides - Capsella bursa-pastoris i Fallopia convolvulus; spring wheat with herbicides - Avena fatua; faba been without herbicides - Galium aparine, Anagallis arvensis i Convolvulus arvensis; faba been with herbicides - Galium aparine, shed diaspores in the greatest degree.

  8. EXPLORATION UNDER SHADE PLANTS OF CASSAVA AND IT’S POTENTIAL AS FORAGE

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    Novia Qomariyah

    2014-01-01

    Full Text Available Utilization of forage plants growing among cassava (Manihot esculenta Crantz is not optimal. Potential for development of integration of both very large and mutually beneficial. Purpose of this study is to explore and identify types of forage that grows in shade of the cassava plant and potential for development as a source of forage. This study took place in March 2014 Month held at IPB Sinar Sari Complex Dramaga. This research method to define area of cassava plants as treatments that cassava plants were planted separately with another crop (monoculture and cassava crops are planted among crops and horticultural crops such as pariah plants, beans, squash and corn (polyculture. Furthermore, observed and forage samples taken were grown in both location and made herbarium and identified its kind. Results: forage crops are grown between cassava monoculture is more diverse than polyculture. Types of forage crops grown on cassava monoculture is Echinochloa colona, Setaria barbata, Family Juncaceae, Cyperus sp., Conjugatum paspalum, Cynodon dactylon, Stenotaphrum secundatum, Axonophus compressus (Swartz P. Beauv, Eleusine indica and Panicum maximum. Types of forage crops grown on cassava polyculture is colona Echinochloa, Setaria barbata, Family Juncaceae, Cyperus sp., Stenotaphrum secundatum, Eleusine indica and Leucaena leucephala.

  9. Weed populations and their buried seeds in rice fields of the MUDA area

    International Nuclear Information System (INIS)

    Ismail Sahid; Noor Faezah Zainuddin; Ho Nai Kin

    2002-01-01

    A total of 25 weed species belonging to 15 families were found in rice fields near Kampung Tandop, in the Muda Irrigation Scheme, Kedah, Malaysia. The dominant weeds in dry-seeded rice were Utricularia aurea Lour., Fimbristylis miliacea (L.) vahl., Echinochloa crusgalli (L.) Beauv., Monochoria vaginalis (Burm. Q Presl. and Najas graminea (Del.) Redl. In wet-seeded rice, the dominant species were N. graminea, Lemna minor L., Sphenoclea zeylanica Gaertn., U. aured, and Sagittaria guayanensis H. B. K., while in volunteer seedling rice fields, the dominant species were Echinochloa colonum (L.) Link., Fimbristylis alboviridis C. B. Clarke, E miliacea, Cyperus babakan Steud. and Fuirena umbellata Rottb. Dry-seeded rice fields contained the highest number of weed seeds (930 910/m 2 in the top 15 cm of soil); volunteer seedling rice fields contained 793.162/m 2 and wet-seeded rice fields 712 228/m 2 . In general, the seed numbers declined with increasing soil depth. At 1015 cm depth, seeds of U aurea and S. zeylanica were the most abundant in dry and wet-seeded rice fields, whilst seeds of Scirpusjuncoides Roxb. and E miliacea were most abundant in volunteer seedling fields. (Author)

  10. Isolation and characterization of culturable endophytic actinobacteria associated with Artemisia annua L.

    Science.gov (United States)

    Li, Jie; Zhao, Guo-Zhen; Huang, Hai-Yu; Qin, Sheng; Zhu, Wen-Yong; Zhao, Li-Xing; Xu, Li-Hua; Zhang, Si; Li, Wen-Jun; Strobel, Gary

    2012-03-01

    Endophytic actinobacteria isolated from Artemisia annua were characterized and evaluated for their bioactivities. A total of 228 isolates representing at least 19 different genera of actinobacteria were obtained and several of them seemed to be novel taxa. An evaluation of antimicrobial activity showed that more isolates possessed activity towards plant pathogens than activity against other pathogenic bacteria or yeasts. High frequencies of PCR amplification were obtained for type I polyketide synthases (PKS-I, 21.1%), type II polyketide synthases (PKS-II, 45.2%) and nonribosomal peptide synthetases (NRPS, 32.5%). The results of herbicidal activity screening indicated that 19 out of 117 samples of fermentation broths completely inhibited the germination of Echinochloa crusgalli. This study indicated that endophytic actinobacteria associated with A. annua are abundant and have potentially beneficial and diverse bioactivities which should be pursued for their biotechnical promise.

  11. The floristic changes on excluded from agricultural production field after single Roundup spraying

    Directory of Open Access Journals (Sweden)

    Wojciech Jabłoński

    2013-12-01

    Full Text Available The purpose of experiment conducting on the field, weedy by Agropyron repens (L. P. B. was established what is the degree of elimination of Agropyron repens plants from experimental plots by single Roundup spraying. The changes of the species composition on the fields with different clover-grass mixtures or with Phacelia tanacaetifolia Benth. were studied as well. The stand tables have been made in the first year of the conducting experiment, to determination the density of weeds, after different agricultural practices. It has been found the great elimination of Agropyron repens (L. P. B. plants after Roundup spraying and the great density of Echinochloa crus-galli (L. P. B. plants. It has been found the great density of Chenopodium album L. at VII treatment and Galinsoga parviflora Cav. at III, V, VII and VIII treatments as well (Table I.

  12. Underexploited tropical plants with promising economic value

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    The apparent advantages of staple plants over the minor tropical plants often result only from the disproportionate research attention they have been given. A world-wide inquiry resulted in a list of 400 promising but neglected species. The 36 most important species are described in compact monographs and concern cereals (Echinochloa turnerana, grain amaranths, quinua and Zosterea mazina), roots and tubers (Arrachacha, cocoyams and taro), vegetables (chaya, hearts of palms, wax gourd, winged bean), fruits (durian, mangosteen, naranjilla, pejibaye, pummelo, soursop, uvilla), oilseeds (babassu palm, buffalo gourd, Caryocar species, Hessenia polycarpa and jojoba), forage (Acacia albida, Brosimum alicastrum Cassia sturtii, saltbushes and tamarugo) and other crops (buriti palm, Calathea lutea, candelilla, guar, guayule, Paspalum vaginatum, ramie and Spirulina).

  13. Sementes nocivas que ocorreram em amostras de sementes de azevém (Lolium multiflorum, analisadas no Rio Grande do Sul nos anos de 1978 e 1979 Weed seeds in ryegrass seeds, analysed in Rio Grande do Sul, during 1978 and 1979

    Directory of Open Access Journals (Sweden)

    H. Giaretta

    1984-06-01

    Full Text Available Foram levantadas informações sobre a qualidade da semente de azevém utilizadas no Rio Grande do Sul e produzida no próprio Estado ou em outras uni dades da Federação e mesmo em outros Países, nos anos de 1978 e 1979. Estas informações foram obtidas através de fichas e Boletins de Análise de Sementes dos Laboratórios de Análise de Sementes (LAS do Rio Grande do Sul. Em 1978 analisou-se 2.319 t de azevém sendo 74% da semente oriunda do Rio Grande do Sul e 26% introduzida, enquanto que das 4.772 t analisadas em 1979 99,6% são do Rio Grande do Sul e 0,4% são introduzidas. O percentual de sementes de azevém, produzidas no Estado, contaminadas com sementes nocivas foi de 61,5% em 1978 e de 60,0% em 1979; e o de sementes int roduzidas no Estado foi de 45,6% em 1978 e de 29,4%em 1979. Foi observado que ent re as sementes originárias do RS destacaram -se com maior ocorrênci a em 1978 as espécies nocivas de Silene gallica, Setaria geniculata, Anthemis cotula, Digitaria adscendens e Echinochloa spp, enquanto que nas sementes int roduzidas desta caram-se Sida spp e Rumex spp; em 1979, na semente oriunda do Estado desta caram-se Amaranthus spp, Silene gallica e Setaria geniculata, enquanto que nas sementes introduzidas a maior ocorrência foi de Setaria geniculata, Echinochloa spp e Solanum spp.This paper presents a quality record of rye-grass seeds produced in Rio Grande do Sul or imported from other countries. It refers to the presence of weeds in ryegrass during 1978 and 1979. These record were obtained in the Analysis Bulletins at the Seed Analysis Laboratory of the Instituto de Pesquisas Agronômicas (IPAGRO Rio Grande do Sul°Brasil and in those from other institutions. This State produced 74% of 2.319 t analysed seeds and 26% come from other places in 1978. In 1979 4.772 t were registred, 99,6% from here and 0,4% from outside. The percentage of ryegrass seeds contaminated with weed seeds produced in the State, in 1978, were 61

  14. Evaluation of allelopathic, decomposition and cytogenetic activities of Jasminum officinale L. f. var. grandiflorum (L.) Kob. on bioassay plants.

    Science.gov (United States)

    Teerarak, Montinee; Laosinwattana, Chamroon; Charoenying, Patchanee

    2010-07-01

    Methanolic extracts prepared from dried leaves of Jasminum officinale f. var. grandiflorum (L.) Kob. (Spanish jasmine) inhibited seed germination and stunted both root and shoot length of the weeds Echinochloa crus-galli (L.) Beauv. and Phaseolus lathyroides L. The main active compound was isolated and determined by spectral data as a secoiridoid glucoside named oleuropein. In addition, a decrease in allelopathic efficacy appeared as the decomposition periods increased. The mitotic index in treated onion root tips decreased with increasing concentrations of the extracts and longer periods of treatment. Likewise, the mitotic phase index was altered in onion incubated with crude extract. Furthermore, crude extract produced mitotic abnormalities resulting from its action on chromatin organization and mitotic spindle. Copyright (c)2010 Elsevier Ltd. All rights reserved.

  15. Weed Hosts of Meloidogyne arenaria and M. incognita Common in Tobacco Fields in South Carolina.

    Science.gov (United States)

    Tedford, E C; Fortnum, B A

    1988-10-01

    Thirty-two weed species common in South Carolina and one cultivar of tobacco were evaluated as hosts of Meloidogyne arenaria race 2 and M. incognita race 3 in the greenhouse. Egg mass production and galling differed (P Rumex crispus, Amaranthus hybridus, Ambrosia artemisiifolia, lpomoea hederacea var. integriuscula, Setaria lutescens, Sida spinosa, Portulaca oleracea, and Rumex acetosella were moderate hosts. Taraxacum officinale, Ipomoea hederacea, Cyperus esculentus, Cynodon dactyIon, Echinochloa crus-galli, Eleusine indica, Sorghum halepense, Setaria viridis, Digitaria sanguinalis, and Datura stramonium were poor hosts for M. arenaria. Amaranthus palmeri, Amaranthus hybridus, Chenopodium album, Euphorbia maculata, Setaria lutescens, Vicia villosa, Sida spinosa, Rumex crispus, and Portulaca oleracea were moderate hosts and Ipomoea hederacea var. integriuscula, Xanthium strumarium, Cyperus esculentus, Cynodon dactylon, Paspalum notatum, Eleusine indica, Setaria viridis, and Rumex acetosella were poor hosts for M. incognita. None of the above were good hosts for M. incognita. Tobacco 'PD4' supported large numbers of both nematode species.

  16. New weed control strategies in maize considering narrow crop rotations with maize, greater ALSresistance in common weeds and application restrictions with regard to active substance

    Directory of Open Access Journals (Sweden)

    Ewert, Katrin

    2014-02-01

    Full Text Available Many herbicides with different HRAC-groups are available for weed control in maize. Because of narrow maize crop rotation summer weeds and warmth loving weeds are encouraged. On the other hand the new confirmed cases of an ALS target site resistance in the weed species Echinochloa crus-galli and Amaranthus retroflexus in Brandenburg, Stellaria media in Saxony and Matricaria recutita and Tripleurospermum perforatum in Brandenburg and Thuringia, warn that in the future the sulfonylureas must be used only according to the management of herbicide resistance. In this way the selection of resistant weed biotypes will be prevented. Moreover in protected water areas it may be a requirement to reduce and to substitute the input of some active substances, for example terbuthylazine and bentazon. The control of E. crus-galli and P. convolvulus with non-sulfonylurea or/and non-terbuthylazine herbicides according to management of herbicide resistance will be discussed.

  17. Características micromorfológicas de biótipos de capim-arroz resistente e suscetível ao quinclorac.

    OpenAIRE

    FERREIRA, E. A.; CONCENÇO, G.; GALON, L.; DELGADO, M. N.; ASPIAZÚ, I.; SILVA, A. F. da; FERREIRA, F. A.; MEIRA, R. M. S. A.

    2012-01-01

    O objetivo deste trabalho foi avaliar o efeito do quinclorac nas características anatômicas de folhas e raízes de biótipos de capim‑arroz (Echinochloa spp.), resistente e suscetível a este herbicida, por meio de avaliações micromorfométricas. As plantas foram cultivadas em vasos de plástico com capacidade de 250 cm³. As imagens dos cortes foram obtidas com microscópio de luz equipado com sistema U‑Photo, acoplado à câmera digital conectada a microcomputador. Na seção transversal da lâmina fol...

  18. Use of crop water stress index for monitoring water stress in some sinanthropic plant species

    Directory of Open Access Journals (Sweden)

    Marinela Roxana ROŞESCU

    2010-11-01

    Full Text Available The water stress indicator (crop water stress index, CWSI is a measure of the transpiration rate of a plant, influenced by the leaf and air temperature difference from the plant’s vicinity and the air pressure deficit of the water vapors from the atmosphere. The experiments were realized in July-August 2008 and 2009 for six species in the cities Pitesti, Mioveni and Maracineni: Cichorium intybus L., Conyza canadensis (L. Cronq., Erigeron annuus L. (Pers., Lactuca serriola Torn., Polygonum aviculare L. and Echinochloa crus-galli (L. Beauv. For those species we calculated the CWSI to estimate the water stress on the selected plants in the urban environment conditions. The analyzed species were exposed to a less accentuated water stress while vegetating in the soil and to a more intense one they were grown in the asphalt cracks. Cichorium intybus had the smallest CWSI value (0.26 while Lactuca serriola the highest one (0.44.

  19. Flora vascular de açudes de uma região do semi-árido da Bahia, Brasil Pond vascular flora in the semi-arid region of Bahia State, Brazil

    Directory of Open Access Journals (Sweden)

    Flávio França

    2003-12-01

    Full Text Available Foram selecionados seis açudes que margeiam a Estrada do Feijão (BA 052, nos municípios de Feira de Santana e Angüera, entre as coordenadas 39º30'-39º00'W e 12º00'-12º30'S. Com a finalidade de se conhecer a flora vascular dos mesmos, esses tipos de plantas foram coletadas de agosto/1996 a dezembro/1997. Registraram-se 121 espécies distribuídas em 46 famílias. As famílias mais representativas foram: Cyperaceae, com 18 espécies (14,9%, Poaceae, com 13 (10,7%, Asteraceae, com 10 (8,3%, Scrophulariaceae e Fabaceae, com 6 (5,0%. As espécies que ocorreram em todos os açudes foram Pistia stratiotes L. (Araceae, Echinochloa colona (L. Link (Poaceae, Nymphaea ampla (Salisb. DC. (Nymphaeaceae e Oxycarium cubense (Poepp. & Kunth. Lye (Cyperaceae.Six ponds were studied between August/1996 and December/1997 at the edge of State Highway BA 052, in the municipalities of Feira de Santana and Angüera, 39º30'-39º00'W and 12º00'-12º30'S.With the aim to know their vascular flora, one hundred and twenty-one species of vascular plants were collected, representing 46 families. The most frequent families were: Cyperaceae with 18 species (14.9%, Poaceae with 13 (10.7%, Asteraceae with 10 (8.3%, Scrophulariaceae and Fabaceae with 6 (5.0%. The species which were recorded in all lakes were: Pistia stratiotes L. (Araceae, Echinochloa colona (L. Link (Poaceae, Nymphaea ampla (Salisb. DC. (Nymphaeaceae and Oxycarium cubense (Poepp. & Kunth. Lye (Cyperaceae.

  20. Quantitative structure-activity relationship (QSAR) directed the discovery of 3-(pyridin-2-yl)benzenesulfonamide derivatives as novel herbicidal agents.

    Science.gov (United States)

    Xie, Yong; Peng, Wei; Ding, Fei; Liu, Shu-Jie; Ma, Hong-Juan; Liu, Chang-Ling

    2018-01-01

    Agrochemicals have been crucial to the production of food, and the need for the development of novel agrochemicals continues unceasing owing to the loss of existing produces via the growth of resistance and the desire for products with more propitious environmental and toxicological patterns. The results of both CoMFA and CoMSIA models indicated that biological activity can effectively be improved through the structural optimisation and molecular design of these synthetic compounds from the aspects of steric, electrostatic, hydrophobic, hydrogen bond donor and acceptor fields. Data of postemergence herbicidal activity in the greenhouse explained that most new 3-(pyridin-2-yl)benzenesulfonamide derivatives (4c-4 t) could control highly effectively against barnyardgrass, foxtail, vetleaf, and youth and old age (herbicidal activity ≥90%); for example, compounds 4q-4 t exhibit excellent biological activity equivalent/superior to commercial saflufenacil/sulcotrione at the low concentration of 37.5 g a.i./ha, and in particular, the herbicidal activity of compound 4 t for four experimental plant species is found to be notably greater than saflufenacil (3.75 g a.i./ha). Meanwhile, compound 4 t also has good crop selectivity for weed control in maize. The novel compounds such as 4 t have remarkable biological activity after the structural optimisation utilising the constructed 3D-QSAR models, i.e. such QSAR models have great accuracy. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. Food Plants Eaten by Amazonian Manatees (Trichechus inunguis, Mammalia : Sirenia

    Directory of Open Access Journals (Sweden)

    Ioni G. Colares

    2002-03-01

    Full Text Available To determine the feeding habits of the Amazonian manatee Trichechus inunguis in some Central Amazonian rivers and lakes, we compared plant epidermis found in the stomach contents and/or faeces of animals with a reference collection of plants present in the studied areas. Twenty five samples from digestive tracts of animals found dead and 25 faeces samples found floating were analyzed. From these samples, 24 aquatic macrophytes were identified. The Gramineae family was identified in 96% of the samples, Paspalum repens and Echinochloa polystachya being the most abundant in the samples. The second most frequent family was the Pontederiaceae primarily Eichhornia crassipes. During the high water period, the animals showed a more selective diet (eight identified species. In the low water period, when food was more scarce, the animals showed a larger diversity of species in their diet (21 species of plants. Differences in the diet among the two studied areas reflected the physiographics characteristics of the region. Amazonian manatees fed mostly on emergent plants.Para determinar o hábito alimentar do peixe-boi da Amazonia em alguns rios e lagos da Amazonia Central, nós comparamos as epidermes de plantas encontradas nos conteúdos alimentares e/ou fezes de animais com uma coleção de referência de epidermes de plantas presentes nas áreas de estudo. Foram analisadas 25 amostras de trato digestivo de animais encontrados mortos e 25 amostras de fezes . A familia Gramineae foi encontrada em 96% das amostras, com maior ocorrência das espécies Paspalum repens e Echinochloa polystachya. A segunda familia mais freqüente foi Pontederiaceae sendo Eichhornia crassipes a espécie predominante. Durante o período de água cheia, os animais apresentaram uma dieta mais seletiva (oito espécies identificadas. Já na água baixa, com menor oferta de alimentos, os animais apresentam uma maior diversidade de espécies em sua dieta (21 espécies de plantas

  2. EFICIÊNCIA DO HERBICIDA OXADIARGYL NO CONTROLE DE PLANTAS DANINHAS NA CULTURA DO ARROZ (Oryza sativa L. IRRIGADO WEED CONTROL EFFICIENCY OF THE HERBICIDE OXADIARGYL IN IRRIGATED RICE (Oryza sativa L.

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    Geraldo José Aparecido Dario

    1999-01-01

    Full Text Available Visando avaliar a eficiência agronômica do herbicida oxadiargyl no controle de plantas daninhas ocorrentes na cultura do arroz (Oryza sativa L. irrigado, semeado em solo drenado, instalou-se ensaio em condição de campo no município de Mococa, SP, em novembro de 1993. O produto foi aplicado em pré-emergência da cultura e das plantas daninhas, nas doses de 320, 400, 480 e 560 g/ha e como padrão utilizou-se duas formulações de oxadiazon, ambas em doses de 1.000 g./ha. Os resultados obtidos permitem concluir: o herbicida oxadiargyl é eficiente no controle da tiririca-do-brejo (Cyperus iria nas quatro doses testadas e do capim-arroz (Echinochloa colonum e capim-macho (Ischaemum rugosum nas três maiores doses; o herbicida oxadiargyl causa leve fitointoxicação à cultura quando aplicado nas duas maiores doses, com os sintomas desaparecendo aos 60 dias após a aplicação; em função do controle das plantas daninhas, o herbicida oxadiargyl aumenta significativamente a produção de grãos de arroz em relação à testemunha não-capinada.In order to evaluate the agronomical efficiency of the herbicide oxadiargyl on weed control in irrigated rice (Oryza sativa L., sowm in a drained field, an experiment was established in Mococa, SP, Brazil, in November 1993. The product was applied in pre-emergence conditions of the crop and weeds, at rates of 320, 400, 480 and 560g/ha, plus a control product (oxadiazon, used in two formulations at rates of 1,000g/ha. The results allowed to conclude that: oxadiargyl is highly efficient against Cyperus iria at all rates tested; and against Echinochloa colonum and Ischaemum rugosum at rates of 400, 480 and 560g/ha. Oxadiargyl caused light phytotoxicity to the rice plants, when applied at rates of 480 and 560g/ha, but the symptoms disappeared 60 days after application. Due to weed control, oxadiargyl caused an increase in rice yield as compared to the non-weeded control.

  3. Períodos de interferência das plantas daninhas na cultura do arroz de terras altas. II - cultivar Caiapó Interference periods of weeds in the upland rice - Caiapó variety

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    Maria Rosangela Malheiros Silva

    2009-01-01

    Full Text Available Os experimentos foram desenvolvidos nos anos agrícolas 2003/2004 e 2004/2005, em área experimental da Universidade Estadual Paulista, Campus de Jaboticabal (SP, com o objetivo de se determinarem os períodos de interferência das plantas daninhas na cultura do arroz de terras altas, cultivar Caiapó. O delineamento experimental foi em blocos ao acaso com quatro repetições e 16 tratamentos. Os tratamentos foram constituídos por períodos crescentes de controle ou de convivência das plantas daninhas após a emergência da cultura: 0-10, 0-20, 0-30, 0-40, 0-50, 0-60, 0-70 dias e 0-colheita. Nos dois anos, as famílias predominantes eram Poaceae, Asteraceae, Amaranthaceae e Malvaceae e as principais plantas daninhas presentes foram: Cyperus rotundus L., Cenchrus echinatus L., Digitaria spp Heist., Echinochloa crus-galli (L. P. Beauv., Brachiaria decumbens Stapf., Eleusine indica Gaertn e Alternanthera tenella Colla. A cultivar de arroz de terras altas Caiapó deve ser mantida sem plantas daninhas nos 30 dias após a emergência.The experiments were carried out in two growing seasons (2003/04 and 2004/05 in an experimental area at São Paulo State University - UNESP, Jaboticabal Campus, to evaluate the weed interference periods on the upland Caiapó rice variety. The experimental design was randomized blocks with 4 replicates and 16 treatments. The treatments consisted of increasing periods of control or coexistence after emergence of the culture: 0-10; 0-20; 0-30; 0-40; 0-50; 0-60; 0-70 days; 0-harvest. The predominant families were Poaceae, Asteraceae, Amaranthaceae and Malvaceae, and the main weeds present were Cyperus rotundus L., Cenchrus echinatus L., Digitaria spp Heist., Echinochloa crus-galli (L. P. Beauv., Brachiaria decumbens Stapf., Eleusine indica Gaertn e Alternanthera tenella Colla for both years. The upland rice cultivar Caiapó is to be kept free of weeds for 30 days after emergence.

  4. Differences in photosynthetic responses of NADP-ME type C4 species to high light.

    Science.gov (United States)

    Romanowska, Elżbieta; Buczyńska, Alicja; Wasilewska, Wioleta; Krupnik, Tomasz; Drożak, Anna; Rogowski, Paweł; Parys, Eugeniusz; Zienkiewicz, Maksymilian

    2017-03-01

    Three species chosen as representatives of NADP-ME C4 subtype exhibit different sensitivity toward photoinhibition, and great photochemical differences were found to exist between the species. These characteristics might be due to the imbalance in the excitation energy between the photosystems present in M and BS cells, and also due to that between species caused by the penetration of light inside the leaves. Such regulation in the distribution of light intensity between M and BS cells shows that co-operation between both the metabolic systems determines effective photosynthesis and reduces the harmful effects of high light on the degradation of PSII through the production of reactive oxygen species (ROS). We have investigated several physiological parameters of NADP-ME-type C4 species (e.g., Zea mays, Echinochloa crus-galli, and Digitaria sanguinalis) grown under moderate light intensity (200 µmol photons m -2  s -1 ) and, subsequently, exposed to excess light intensity (HL, 1600 µmol photons m -2  s -1 ). Our main interest was to understand why these species, grown under identical conditions, differ in their responses toward high light, and what is the physiological significance of these differences. Among the investigated species, Echinochloa crus-galli is best adapted to HL treatment. High resistance of the photosynthetic apparatus of E. crus-galli to HL was accompanied by an elevated level of phosphorylation of PSII proteins, and higher values of photochemical quenching, ATP/ADP ratio, activity of PSI and PSII complexes, as well as integrity of the thylakoid membranes. It was also shown that the non-radiative dissipation of energy in the studied plants was not dependent on carotenoid contents and, thus, other photoprotective mechanisms might have been engaged under HL stress conditions. The activity of the enzymes superoxide dismutase and ascorbate peroxidase as well as the content of malondialdehyde and H 2 O 2 suggests that antioxidant defense is not

  5. Diversity of segetal weeds in pea (Pisum sativum L. depending on crops chosen for a crop rotation system

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    Marta K. Kostrzewska

    2014-04-01

    Full Text Available This study, lasting from 1999 to 2006, was conducted at the Research Station in Tomaszkowo, which belongs to the University of Warmia and Mazury in Olsztyn. The experiment was set up on brown rusty soil classified as good rye complex 5 in the Polish soil valuation system. The analysis comprised weeds in fields sown with pea cultivated in two four-field crop rotation systems with a different first crop: A. potato – spring barley – pea – spring barley; B. mixture of spring barley with pea – spring barley – pea – spring barley. Every year, at the 2–3 true leaf stage of pea, the species composition and density of individual weed species were determined; in addition, before harvesting the main crop, the dry matter of weeds was weighed. The results were used to analyze the constancy of weed taxa, species diversity, and the evenness and dominance indices, to determine the relationships between all biological indicators analyzed and weather conditions, and to calculate the indices of similarity, in terms of species composition, density and biomass of weeds, between the crop rotations compared. The species richness, density and biomass of weeds in fields with field pea were not differentiated by the choice of the initial crop in a given rotation system. In the spring, the total number of identified taxa was 28 and it increased to 36 before the harvest of pea plants. Chenopodium album and Echinochloa crus-galli were the most numerous. Chenopodium album, Echinochloa crus-galli, Sonchus arvensis, Fallopia convolvulus and Viola arvensis were constant in all treatments, regardless of what the first crop in rotation was or when the observations were made. The species diversity and the evenness and species dominance indices varied significantly between years and dates of observations. Species diversity calculated on the basis of the density of weed species was higher in the rotation with a mixture of cereals and legumes, while that calculated on

  6. Levantamento da infestação de plantas aquáticas em Porto Primavera antes do enchimento final do reservatório Aquatic plant infestation assessment in Porto Primavera reservoir before final filling

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    D Martins

    2009-12-01

    Full Text Available O objetivo deste trabalho foi identificar as plantas aquáticas e os níveis de infestação de cada espécie em Porto Primavera antes do enchimento final do reservatório. Foram avaliados todos os focos de vegetação aquática no reservatório (72 pontos, sendo os pontos demarcados com um aparelho de GPS. As espécies foram identificadas e estimouse visualmente (tamanho da área a distribuição proporcional das plantas no foco de infestação. Após a identificação, foram encontradas 18 espécies de plantas aquáticas vegetando no reservatório, das quais foram determinadas a frequência de espécie de planta aquática e a distribuição dentro do sistema de geração de energia. As espécies encontradas no reservatório foram: Eichhornia crassipes, Eichhornia azurea, Pistia stratiotes, Paspalum repens, Cyperus brevifolius, Paspalum conspersum, Echinochloa polystachya, Egeria densa, Egeria najas, Polygonum hidropiperoides, Polygonum lapathifolium, Alternanthera philoxeroides, Eleocharis sellowiana, Nymphaea ampla, Pontederia cordata, Salvinia auriculata, Salvinia rotundifolia e Typha angustifolia. As maiores frequências relativas foram observadas em: E. azurea (36,11%, E. crassipes (16,67%, P. stratiotes (13,89%, S. auriculata (13,89%, C. brevifolius (11,11% e P. lapathifolium (6,94%.The objective of this work was to identify the aquatic plants and their infestation levels in Porto Primavera Reservoir in the state of São Paulo, Brazil, before the reservoir was filled. The aquatic vegetation in the dam (72 sites were evaluated and marked with GPS equipment. The species were identified and a visual estimate (site size of the proportional distribution of the plants in the infestation foci was carried out. After plant identification, eighteen macrophyte species were found in the dam and their frequency and distribution were determined as follows: Eichhornia crassipes, Eichhornia azurea, Pistia stratiotes, Paspalum repens, Cyperus brevifolius

  7. Efeito alelopático do fruto de Sapindus saponaria na germinação e na morfologia de plântulas daninhas e de hortaliças Allelopathic effect of Sapindus saponaria fruit on germination and seedlings morphology of weed and vegetables

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    P.U. Grisi

    2011-06-01

    Full Text Available O objetivo deste estudo foi avaliar o potencial alelopático do extrato aquoso de frutos de Sapindus saponaria (sabão-de-soldado na germinação de diásporos e na morfologia de plântulas de Lactuca sativa (alface, Allium cepa (cebola, Echinochloa crus-galli (capim-arroz e Ipomoea grandifolia (corda-de-viola. O extrato aquoso dos frutos foi preparado na proporção de 100 g de material vegetal fresco para 1.000 mL de água destilada, produzindo-se a concentração de 10%. A partir dele, foram feitas diluições em água destilada para 7,5, 5,0 e 2,5%. O extrato do fruto Sapindus saponaria evidenciou potencialidades alelopáticas tanto sobre as espécies de hortaliças quanto sobre as de plantas daninhas. O efeito inibitório sobre o processo de germinação dos diásporos e morfologia das plântulas de alface, cebola, capim-arroz e corda-de-viola foi dependente da concentração. Os resultados mostram o potencial do extrato proveniente dos frutos de Sapindus saponaria como um herbicida a ser utilizado em práticas de agricultura sustentável.The aim of this study was to evaluate the allelopathic potential of the aqueous extract of Sapindus saponaria (soapberry fruit on seed germination and seedling morphology of Lactuca sativa (lettuce, Allium cepa (onion, Echinochloa crus-galli (barnyard grass, and Ipomoea grandifolia (morningglory. The aqueous extract of the fruit was prepared using 100 g of fresh plant material dissolved in 1,000 mL of distilled water, resulting in 10% concentration. The dilutions were made with distilled water to 7.5, 5.0, and 2.5%. The Sapindus saponaria fruit extract showed allelopathic potential on the vegetable and weed species. The inhibitory effect on the seed germination process and seedling morphology of lettuce, onion, barnyard grass, and morningglory was concentration dependent. The results showed the potential use of the Sapindus saponaria fruit extract as herbicide in sustainable agricultural practices.

  8. Efeito do bentazon e bentazon + dichlorprop na cultura do arroz irrigado e sobre as plantas daninhas Effect of bentazon and bentazon + dichlorprop on irrigated rice and weeds

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    C.A.L. dos Santos

    1979-06-01

    Full Text Available Foi instalado um experimento de campo, em solo barrento, com a finalidade de se verificar o efeito do bentazon e da mistura de bentazon + dichlorprop sobre o desenvolvimento do arroz em cultura irrigada e sobre o controle das plantas daninhas. Os tratamentos utilizados foram os seguintes: bentazon á 0,75-1,00 e1,50 kg/ha; bentazon + dichlorprop a 0,80 + 1,00 e 1,00 + 1,40 kg/ha; propanil a 4,20 kg/ha (tratamento padrão; testemunha capinada e testemunha sem capina. Todas as pulverizações foram realizadas em pósemergência. As plantas daninhas encontradas no experimento foram: capituva - Echinochloa colonum (L Link, tiririca amarela - Cyperus esculentus L., beldroega - Portulaca oleracea L. e carurú comum - Amaranthus viridis L. Bentazon a 1,00 e 1,50 kg/ha e bentazon + dichlorprop a 1,00 + 1,40 kg/ha foram eficientes no controle de P. oleracea, A. viridis e C. esculentus; já a dose menor de bentazon apresentou bons resultados contra P. oleracea e A. viridis, enquanto que a dose menor de bentazon + dichlorprop controlou apenas P. oleracea. Propanil, de uma maneira geral, proporcionou eficiente ação sobre as plantas daninhas. Nas condições em que foi realizado o experimento nenhum dos herbicidas, nas suas respectivas doses, apresentou fitotoxicidade para as plantas de arroz da variedade IAC-435 ou prejudicou a produção da cultura.Bentazon at 0.75 - 1.00 and 1.50 kg/ha a.i ., bentazon + dichlorprop at 0.80 + 1.00 and 1.00 + 1.40 kg and propanil at 4.20 kg were applied in post-emergence on irrigated rice, against the following weeds: Echinochloa colonum (L. Link, Cy-perus esc-ulentus L., Portulaca oleracea L. and Amaranthus viridis L. Bentazon at 1.00 - 1.50 kg and bentazon + dichlorprop at 1.00 + 1.40 kg gave good control of P. oleracea, A. viridis and C. esculentus; bentazon at 0.75 kg controlled P. oleracea and A. viridis; bentazon + dichlorprop at 0.80 + 1.00 kg only showed effeciency for P. oleracea; propanil, in general, gave good

  9. Avaliação da sensibilidade de diversas espécies de plantas daninhas aquáticas ao carfentrazone-ethyl, em ambiente controlado Assessment of sensitivity of several aquatic weeds to carfentrazone-ethyl under controlled environment

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    L.L. Foloni

    2005-06-01

    Full Text Available Plantas aquáticas, especialmente macrófitas, tornam-se sério problema em hidrelétricas, afetando a múltipla utilização dos corpos d'água, incluindo produção de peixes e atividades de pesca, perdas d'água por evapotranspiração, esportes aquáticos, canoagem, irrigação e produção de energia nas usinas hidrelétricas. Com o objetivo de analisar o potencial de uso do carfentrazone-ethyl no controle das principais plantas daninhas aquáticas no Brasil, foi instalado um experimento em vasos com água. Utilizaram-se os seguintes tratamentos herbicidas (g i.a. ha-1: carfentrazone-ethyl a 15, 30 e 60; glyphosate a 4.536; 2,4-D a 4.690; imazapyr a 1.250; e uma testemunha sem herbicida. Esses tratamentos foram testados nas seguintes espécies: Eichhornia crassipes, Salvinia auriculata, Pistia stratiotes, Myriophyllum aquaticum, Brachiaria arrecta, Hydrocotyle umbellata, Typha sp. e Echinochloa polystachya. As avaliações foram efetuadas aos 7, 14, 21 e 28 dias após os tratamentos. Os resultados mostraram que o carfentrazone-ethyl foi eficiente no controle de E. crassipes (maior dose e P. stratiotes (duas maiores doses, com efeito supressivo sobre S. auriculata. Foi observado que nas outras plantas daninhas estudadas não houve eficiência de controle.Aquatic weeds, especially macrophytes, are a serious problem in hydroelectric plant systems, affecting the multiple use of water, such as fish production and fishing activities, water losses by evapotranspiration, aquatic sports, boating, irrigation and hydroelectric power production. An experiment using boxes filled with water was carried out to analyze the potential use of carfentrazone-ethyl in the control of the main aquatic weeds in Brazil. The following herbicide treatments (g i.a. ha-1 were used: carfentrazone-ethyl at 15, 30 and 60; glyphosate at 4,536; 2,4D at 4,690; imazapyr at 1,250, and no herbicide. These treatments were tested on the species: Eichhornia crassipes, Salvinia

  10. EFFECT OF SOWING DATE AND WEED CONTROL METHOD ON THE GROWTH AND YIELD OF SOYBEAN

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    Nasrin Akter

    2016-06-01

    Full Text Available Sowing date and weed management play a significant role in determining soybean growth, development and seed yield. Results showed that different sowing date and weed control methods had significant effect on relative weed density, weed biomass, weed control efficiency, plant height, dry weight plant-1 and seed yield of soybean. Among the infested weed species in the experimental field the dominant weeds were Lindernia procumbens (44.78%, Echinochloa colonum (26.39% and Cynodon dactylon (16.30%. The results also revealed that early sowing (2 January brought about the highest seed yield (2.17 t ha-1 and sowing delay (1 February resulted in the lowest yield (1.64 t ha-1. Two times hand weeding (20 and 40 DAS controlled the weeds most effectively and led to highest seed yield (2.23 t ha-1 which was statistically similar (2.19 t ha-1 with herbicide application. Combination effect showed that the highest seed yield (2.50 t ha-1 was obtained from 2 January sowing when the crop was weeded by hand at 20 and 40 DAS.

  11. Physiological Age Status of Female Adults and Off-Season Survival of Rice Leaffolder Cnaphalocrocis medinalis in India

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    Padmavathi Chintalapati

    2015-09-01

    Full Text Available Rice leaffolder, Cnaphalocrocis medinalis, is one of the major foliage feeders found in the rice growing regions in India. When the crop was at maturity, numerous adults of rice leaffolder were found in the rice fields though the larval population gradually decreased, and no eggs were found on rice leaves. The population characteristics of C. medinalis were assessed based on the physiological age status of adults at different crop growth stages. Based on egg development within ovarioles, ovariole appearance, number and colour of fat bodies, and characteristics of bursa copulatrix, physiological age status of the adults was described, which served as a basis for the determination of age composition. C. medinalis adults were found during the first week of August on rice plants, of which 44% were in Age 0 with immature ovaries, indicating immigrants. However, 28% adults each were at Ages 1–2 with developing ovaries, indicating local breeding population. The carryover and off-season survival of C. medinalis were also studied to determine the contribution of the alternative hosts in the population growth that helped in devising efficient management strategies. Rice was the most preferred host followed by Triticum aestivum, Echinochloa crusgulli and Brachiaria plantaginea. Various routes of the carryover of C. medinalis from season to season were discussed.

  12. The weed species composition in a reed canary grass (Phalaris arundinacea L. plantation for energy purposes depending on its age

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    Tomasz R. Sekutowski

    2014-12-01

    Full Text Available The present experiment, carried out in nine production fields of reed canary grass (Phalaris arundinacea grown for energy purposes, evaluated the effect of plantation age on the occurrence and species composition of weeds. The selected plantations were divided into 3 groups that were conventionally called “young” (1–2 years old, “middle-aged” (3–5 years old, and “older” plantations (6–8 years old. Regardless of plantation age, altogether 43 species were found in the experimental fields. Moreover, 6 species were common for all the plantations and were found in them regardless of plantation age. The least species, only 18, were found on the “young” plantations, almost twice more on the “older” ones (30 species, whereas the largest spectrum of species was found in the “middle-aged” plantations (33 species. In the “young” plantations, annual weeds were the most common, with the highest constancy and coverage index found for Chenopodium album, Matricaria maritima ssp. inodora and Echinochloa crus-galli. The greatest variation in species was found in the “middle-aged” plantations. However, only 4 species achieved the highest constancy and coverage index: Matricaria maritima ssp. inodora, Cirsium arvense, Poa trivialis and Taraxacum officinale. Furthermore, perennial weeds were found to be dominant in the “older” plantations. Within this group, Poa trivialis, Taraxacum officinale, Urtica dioica, Plantago maior, and Cirsium arvense had the highest constancy and coverage index.

  13. Allelopathy relationship between plants and their use in organic farming

    Science.gov (United States)

    Marian, M.; Voşgan, Z.; Mare Roşca, O.; Mihalescu, L.

    2017-05-01

    Allelopathy is a process still little studied in the plant world, if we refer to the diversity of biochemical compounds, through which plants can interact with each other, with fungi or bacteria. Biochemical "dialogue" between organisms may have stimulatory or inhibitory effects, contributing to numerical setting of the populations, the assertion of some species over others, the establishment and strengthen of plant communities. Practically, the allelopathy can be exploited in organic farming in understanding and identifying compatibility between species, to finding natural substances with herbicide potential. In experiments conducted, diluted extracts of Taraxacum officinale and Cirsium vulgare strongly inhibited the germination and growth of corn and beans, while Hedera helix produced the same effect, but at higher concentrations of the extract. Humulus lupulus extract has a stimulating effect on the two species and it is possible to use as natural fertilizer. Extracts of Chenopodium album works as stimulator for Beta vulgaris, and potent inhibitor for Triticum aestivum. Agropyron repens is an aggressive competitor for Lycopersicon esculentum and Capsicum annuum, producing a strong inhibition. Juglans regia extracts and especially those of Satureja hortensis, can be used as natural herbicides for up delay germination and growth suppression for the species: Echinochloa crus-galli and Setaria glauca.

  14. Arbuscular mycorrhizal fungi in chronically petroleum-contaminated soils in Mexico and the effects of petroleum hydrocarbons on spore germination.

    Science.gov (United States)

    Franco-Ramírez, Alicia; Ferrera-Cerrato, Ronald; Varela-Fregoso, Lucía; Pérez-Moreno, Jesús; Alarcón, Alejandro

    2007-10-01

    Arbuscular mycorrhizal fungi (AMF) have been hypothesized to enhance plant adaptation and growth in petroleum-contaminated soils. Nevertheless, neither AMF-biodiversity under chronically petroleum-contaminated soils nor spore germination response to petroleum hydrocarbons has been well studied. Chronically petroleum-contaminated rhizosphere soil and roots from Echinochloa polystachya, Citrus aurantifolia and C. aurantium were collected from Activo Cinco Presidentes, Tabasco, Mexico. Root colonization and spore abundance were evaluated. Additionally, rhizosphere soil samples were propagated using Sorghum vulgare L. as a plant trap under greenhouse conditions; subsequently, AMF-spores were identified. AMF-colonization ranged from 63 to 77% while spore number ranged from 715 to 912 in 100 g soil, suggesting that AMF tolerate the presence of petroleum hydrocarbons in the rhizosphere. From grass species, four AMF-morphospecies were identified: Glomus ambisporum, G. sinuosum (previously described as Sclerocystis sinuosum), Acaulospora laevis, and Ambispora gerdermanni. From citrus trees, four AMF-species were also identified: Scutellospora heterogama, G. ambisporum, Acaulospora scrobiculata, and G. citricola. In a second study, it was observed that spore germination and hyphal length of G. mosseae, G. ambisporum, and S. heterogama were significantly reduced by either volatile compounds of crude oil or increased concentrations of benzo[a ]pyrene or phenanthrene in water-agar.

  15. Phytosociology of weeds associated with rice crops in the department of Tolima, Colombia

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    Javier Ramírez S.

    2015-04-01

    Full Text Available Phytosociological studies allow for the characterization and descriptive analysis of weed communities in crops. This study aimed to characterize the weed communities associated with weed crops in the "Centro, Meseta, and Norte" zones of the Tolima Department. The study was conducted in 96 commercial lots, in which a 1 ha area was marked off for the sampling. The development stage, density and cover of the weeds were evaluated. The importance value index, the alpha diversity indices of Shannon-Wiener, Simpson and uniformity as well as the similarity indices of Jaccard, Sorensen and Steinhaus were calculated. For the entire department, 42 weed species were identified, with Echinochloa colona being the principal one in all of the zones. In the Centro zone, 27 species were identified; in the Meseta zone, 31 species were identified; and, in the Norte zone, 38 species were identified. The alpha indices demonstrated that the Meseta zone was the most diverse. The Jaccard and Sorensen indices showed dissimilarity in the weed community for all of the comparisons of the zones. The Steinhaus coefficient registered the highest similarity intensity between the Centro and Norte zones.

  16. Occurence, spread and possibilities of invasive weeds control in sugar beet

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    Konstantinović Branko I.

    2006-01-01

    Full Text Available Floristically rich and diverse weed comunity of sugar beet is in our country represented by 150 weed species. They are not all equaly significant in weediness of this crop. Only a limited number of them participate in weed comunity composition. These are: Abuthilon theophrasti Medic., Ambrosia artemisiifolia L., Amaranthus retroflexus L., Chenopodium album L., Cirsium arvense (L Scop., Convolvulus arvensis L., Cynodon dactylon (L Pers. Digitaria sanguinalis (L Scop., Hibiscus trionum L., Rubus caesius L. Echinochloa crus-gall L., Polygonum aviculare L., P. lapathifolium L., P. persicaria L., Setaria glauca (L P. B., S. viridis (L P. B., Solanum nigrum L. and Sorghum halepense (L Pers. In shooting period up to 4-8 weeks upon emergence, sugar beet is under the haviest harmfull inluence of weeds, especially invasive ones such as: Abuthilon theophrasti Medic. Ambrosia artemisiifolia L., Cirsium arvense (L Scop., Iva xanthifolia L. Sorghum halepense (L Pers. and Xanthium strumarium L. Sugar beet growing requires intensive cultural practices, i.e. basic and additional tillage and cultivation. Due to the widening of weed problems, frequent herbicide use in several applications is needed in the longer time period.

  17. The synergistic effects of 2,4-D dimethyl amine and propanil herbicides on weed population in rice agroecosystem

    International Nuclear Information System (INIS)

    Nashriyah Mat; Ramli Ishak; Sabri Junoh; Ismail Sahid

    2002-01-01

    Four treatments with the herbicides 2,4-D dimethyl amine and propanil were carried out in two consecutive rice planting seasons, to study the synergistic effect of 2,4-D dimethyl amine and propanil on rice weed populations at Pasir Panjang, the Northwest Selangor Project (PBLS), Projek Barat Laut Selangor) rice granary area. The treatments were control, 1x recommended rate (single dose), 2x recommended rate (double dose) of 2,4-D dimethyl amine and farmer practice. In all plots, propanil herbicide was applied at similar rate. Among the ecological indices measured were Simpson Index of diversity and importance (I.V.). A total number of 19 weed species was identified and the most common important weed was Najas graminae Del. The second most commonly found important weed was Scirpus lateriflorus Gmel. Other important weeds frequently found were Echinochloa crus-galli (L.) Beauv. and Fimbristylis miliacea (L.) Vahl. In the rice agroecosystem, species diversity of weeds was affected but total weed biomass was not affected synergistically by the mixture of 2,4-D dimethyl amine and propanil. The negative synergistic effect of 2,4-D dimethyl amine and propanil was to increase the total biomass of Scirpus lateriflorus, at 2x recommended dose rate of 2,4-D dimethyl amine. (Author)

  18. Variação temporal e vertical de atributos químicos de um gleissolo do Rio Guamá cultivado com Canaranas Temporary and vertical variation of chemical attributes of a gleysol of the Guamá River cultivated with Canaranas

    Directory of Open Access Journals (Sweden)

    Eliana Maria Acioli de Abreu

    2007-04-01

    Full Text Available Os sedimentos transportados pelas águas barrentas do rio Guamá e a heterogeneidade dessas substâncias são responsáveis pela formação do solo e pela diversidade de características químicas na área inundável. Este trabalho teve como objetivo determinar os atributos físicos e químicos de um solo de várzea baixa do rio Guamá, em diferentes épocas, cultivado com canarana de Paramaribo (Echinochloa polystachya H.B.K e canarana erecta lisa (Echinochloa pyramidales Lam. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 4 x 4 (quatro profundidades e quatro épocas de amostragem, com seis repetições. Amostras compostas de solo foram coletadas em seis pontos eqüidistantes, a partir de uma transecção, nas profundidades de 0-10, 10-20, 20-30 e 30-40 cm, nos meses de maio, agosto e novembro/2002 e fevereiro/2003. Foram determinados a granulometria, matéria orgânica, pH em H2O, pH em KCl, P extraível, K trocável, Al trocável, Ca e Mg trocáveis e os micronutrientes: Cu, Mn, Zn e Fe. Os solos da área estudada estão inseridos na unidade dos Gleissolos e caracterizam-se por serem pouco desenvolvidos, mal drenados, normalmente ácidos, ocorrendo no perfil horizonte franco-argilo-siltoso. Houve influência da sazonalidade na composição química do solo; na época mais chuvosa e de inundação mais intensa da várzea, correspondente ao mês de fevereiro, observou-se aumento do pH nos teores de Cu e de Fe e decréscimos nos de Mg e de Al trocável; no período de menor umidade do solo, a saturação por bases e a CTC foram mais elevadas. O Fe foi o nutriente que apresentou maior variação nos seus teores com a inundação do solo, cujo aumento foi superior a 1.000 % no período de maior inundação do solo (fevereiro.Sediments carried away by the muddy waters of the Guamá River and the heterogeneity of these substances are responsible for the soil formation and diversity of chemical characteristics in the

  19. Effects of different nitrogen levels on phytotoxicity of some allelopathic crops

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    Y. NOROUZI

    2016-04-01

    Full Text Available Intensive usage of herbicides can result in the serious negative impacts on environment. Allelopathy by reducing seed germination and early seedling growth can play a fundamental role in suppressing weeds in crop fields. The effectiveness of allelochemicals is governed by different factors such as soil nutrient status, pH and microorganisms. Outdoor pot experiments were conducted at the Faculty of Agriculture and Natural Resources of Razi University, Kermanshah, Iran, in 2013, to evaluate the effects of different levels of N fertilizer (0, 150, 300 kg ha-1 on the suppressing effects of alfalfa (Medicago sativa L., sorghum (Sorghum bicolor L., and tobacco (Nicotiana tabacum L. plant materials on emergence and growth parameters of some weed species including Johnson grass (Sorghum halepense (L. Pers., barnyard grass (Echinochloa crus-galli (L. Beauv. and redroot pigweed (Amaranthus retroflexus L.. Results indicated that adding plant materials of tobacco, sorghum, and alfalfa substantially reduced seed germination and early growth of the tested weeds. However, the weed species responded differently to the presence of the allelopathic plant materials. The use of N fertilizer had significant effects on the inhibitory potentials of the allelopathic plants. However, we didn't find consistent trends regarding the responses of the allelopathic crops to elevated N fertilizer levels in related to the traits under study.

  20. Impacts of Different Water Pollution Sources on Antioxidant Defense Ability in Three Aquatic Macrophytes in Assiut Province, Egypt

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    Mohamed A.A. Gadallah

    2014-08-01

    Full Text Available The present study was undertaken to evaluate the impacts of surface water pollution with wastes coming from sewage effluents (Site 2, agricultural runoff (Site 4 and oils and detergents factory (Site 3 on the stability of leaf membrane (measured as injury %, hydrogen peroxide (H2O2, ascorbic acid (Asc A, lipid peroxidation, chlorophyll (Chl content, soluble sugars (SS, soluble proteins (SP and total free amino acids (TAA of Cyperus alopeucroides, Persicaria salicifolia and Echinochloa stagnina. Concentration of H2O2, MDA and TAA were higher in the three plants collected from polluted sites as compared with those of plants grown in control Nile site (Site1. The opposite was true for Asc A, SS and SP where their concentrations reduced significantly in response to water pollution. Leaf membrane was more damaged (high injury % in plants exposed to wastes from different sources than in plants growing at control site. The results of this study indicated that water pollution reduced the oxidative defense abilities in the three plants through reduction of Asc A activities, enhancement of H2O2 production and increasing MDA accumulation. In addition it impaired the metabolic activity through lowering the SS and SP contents and enhancement of TAA accumulation and increase membrane injury. The over production of hydrogen peroxide by the studied aquatic plants under water pollution could be used as an oxygen source needed to oxidize the more resistant organic and inorganic pollutants and used for pollution control and municipal and industrial wastewater treatment.

  1. Genetic diversity and genomic resources available for the small millet crops to accelerate a New Green Revolution

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    Travis Luc Goron

    2015-03-01

    Full Text Available Small millets are nutrient-rich food sources traditionally grown and consumed by subsistence farmers in Asia and Africa. They include finger millet (Eleusine coracana, foxtail millet (Setaria italica, kodo millet (Paspalum scrobiculatum, proso millet (Panicum miliaceum, barnyard millet (Echinochloa spp., and little millet (Panicum sumatrense. Local farmers value the small millets for their nutritional and health, tolerance to extreme stress including drought, and ability to grow under low nutrient input conditions, ideal in an era of climate change and steadily depleting natural resources. Little scientific attention has been paid to these crops, hence they have been termed orphan cereals. Despite this challenge, an advantageous quality of the small millets is that they continue to be grown in remote regions of the world which has preserved their biodiversity, providing breeders with unique alleles for crop improvement. The purpose of this review, first, is to highlight the diverse traits of each small millet species that are valued by farmers and consumers (e.g. nutritional quality which hold potential for selection, improvement or mechanistic study. For each species, the germplasm, genetic and genomic resources available will then be described as potential tools to exploit this biodiversity. The review will conclude with noting current trends and gaps in the literature and make recommendations on how to better preserve and utilize diversity within these species to accelerate a New Green Revolution for subsistence farmers in Asia and Africa.

  2. Biology of rice bug Leptocorisa oratorius (Fabricius) (Hemiptera: Alydidae), population change and alternative host plants.

    Science.gov (United States)

    Rattanapun, W

    2013-01-01

    Leptocorisa oratorius (Fabricius) (Hemiptera: Alydidae) is a major rice pest which feeds on the sap of stems and rice seeds. Some graminaceous weed species serve as an alternative host of L. oratorius causing outbreaks throughout the rice growing season. Population changes of L. oratorius during both rice growing seasons - wet-season rice and dry-season rice - including the influence of alternative host, barnyard grass Echinochloa crus-galli (Graminaceae) on the development of L. oratorius was studied. Results presented that L. oratorius was the dominant pest species during the late phase of rice growth. Adults of L. oratorius started their migrations to wet-season rice at the vegetative stage of rice growth, while they migrated to dry-season rice at the repropuctive stage of rice growth. Leptocorisa oratorius breds rapidly in rice fields. Meanwhile, other adults migrated to the rice field. The population of adults and nymphs significantly increased from the reproductive stage to grain formation and ripening stage in both rice growing seasons. The population of nymphs was greater than adults but not significantly different in their number of individuals. Leptocorisa oratorius had one generation in each rice growing season. The results of the host plant study indicated that L oratorius developed completely in barnyard grass E. crus-galli as well as rice Oriza sativa (Graminaceae). However, L. oratorius preferred rice to barnyard grass for feeding and oviposition.

  3. Synergistic Antifungal, Allelopatic and Anti-Proliferative Potential of Salvia officinalis L., and Thymus vulgaris L. Essential Oils

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    Ersilia Alexa

    2018-01-01

    Full Text Available The current study aimed to investigate the chemical composition and the synergistic potential of two essential oils (EOs, as obtained from Salvia officinalis L. (SEO, and Thymus vulgaris L. (TEO. The antifungal potential was tested in vitro against Fusarium graminearum (Fg 06_17, the herbicidal effect was studied using weed seeds of Amaranthus retroflexus (ARET, Chenopodium album (CALB, Echinochloa crus-galli (EGAL, but also wheat seeds (WS of the Lovrin variety and tomato seeds Saint-Pierre of the variety. The GC-MS profile highlights that the mains compounds identified in SEO were: caryophyllene (25.364%, camphene (14.139%, eucalyptol (13.902%, and β-pinene (11.230%, while in TEO, the predominant phytochemicals were: γ-terpinene (68.415% and p-thymol (24.721%. The results indicated that the tested EOs alone as well as in combination have allelopathic effect against investigated seeds, while the synergistic effect of TEO and SEO in terms of fungal growth was demonstrated at a level of 0.06%. Thyme and sage EOs exhibited in vitro anti-proliferative activity on two melanoma cell lines, namely A375 human melanoma and B164A5 mouse melanoma alone, as well as in combination. SEO was most effective in terms of decreasing the cell viability of murine and human melanoma cell lines when compared to TEO.

  4. Synthesis, Characterization, Luminescence and Biological Activity of Two Lanthanide Complexes Involving Mixed Ligands

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Deyun; Guo, Haifu; Qin, Liang [Zhaoqing Univ., Zhaoqing (China); Xu, Jun [Jinan Univ., Guangzhou (China)

    2013-09-15

    Two new isostructural dinuclear complexes, Ln{sub 2}(4-cpa){sub 6}(bpy){sub 2} (Ln = Eu (1); Tb (2), 4-cpa = 4-chlorophenyl-acetate, bpy = 2,2'-bipyridine), have been hydrothermally synthesized and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder X-ray diffraction and single-crystal X-ray diffraction. The lanthanide ions are bridged by two bidentate and two terdentate carboxylate groups to give centrosymmetric dimers with Ln···Ln separations of 3.967(2) and 3.956(3) A, respectively. Each metal atom is nine-coordinate and exhibits a distorted tricapped trigonal prismatic geometry. Three-dimensional fluorescence spectra show that both 1 and 2 emit bright red and green luminescence at room temperature, with long lifetimes of up to 0.369 ms (at 614 nm) and 0.432 ms (at 543 nm), respectively. Moreover, poor luminescence efficiency has been noted for complex 2. The 4-Hcpa ligand and complexes 1-2 have been screened for their phytogrowth-inhibitory activities against Brassica napus L. and Echinochloa crusgalli L., and the results are compared with the activity of quizalofop-P-ethyl.

  5. Application of electrical capacitance measurement for in situ monitoring of competitive interactions between maize and weed plants

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    Imre Cseresnyés

    2016-06-01

    Full Text Available Applicability of root electrical capacitance (EC measurement for monitoring of crop–weed competition was studied in a pot experiment. Maize (Zea mays L. was grown both alone and with Echinochloa crus-galli or Abutilon theophrasti in different densities with regular measurement of root EC. Plants were harvested 42 days after planting to determine above- and belowground biomass. Depending on weed density, E. crus-galli-A. theophrasti interaction reduced the root EC of maize by 22–66% and 3–57%, respectively. Competitive effect of crop on weeds and intraspecific competition among weeds could also be detected by EC values: E. crus-galli was less sensitive both to the presence of maize and to intraspecific competition than A. theophrasti. Strong linear correlations between root dry mass and root EC for crop and weeds (with R2 from 0.901 to 0.956 were obtained by regression analyses at the end of the experiment. EC monitoring informed us on the emergence time of competition: E. crus-galli interfered with maize root growth a week earlier then A. theophrasti, and increasing weed densities accelerated the emergence of competition. In conclusion, the simple, non-destructive EC method should be considered a potential in situ technique for pot studies on crop–weed competition, which may partially substitute the intrusive techniques commonly used in agricultural researches.

  6. Crown sheath rot of rice: host-range and varietal resistance to Gaeumannomyces graminis var. graminis

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    Cecília do Nascimento Peixoto

    2014-09-01

    Full Text Available Several gramineous plants occurring in rice fields show symptoms of crown sheath rot of rice, caused by Gaeumannomyces graminis var. graminis (Ggg, under natural conditions of infection. The pathogenicity of the Ggg-a 01 isolate, collected from rice, was tested on seven grass species and eight cereals, under greenhouse conditions, in order to get information on host-range and resistance of rice genotypes to crown sheath rot. The inoculation tests showed that the rice isolate was pathogenic to weeds such as Echinochloa crusgalli, Pennisetum setosum, Brachiaria sp., Digitaria horizontalis, Brachiaria plantaginea, Eleusine indica and Cenchrus echinatus, and that these species are potential hosts to the pathogen. Winter cereals such as wheat, oat, rye, barley and triticale, as well as sorghum, maize and millet, presented different degrees of susceptibility to the Ggg-a isolate. Significant differences were observed in relation to lesion height and production of hyphopodia and perithecia on culms. Perithecia were not observed on millet, sorghum, southern sandbur and maize. The resistance of 58 upland rice genotypes was tested, and the SCIA16 and SCIA08 genotypes presented lesion height significantly smaller, being considered resistant, when compared to the highly susceptible CNAS10351 genotype.

  7. The effect of different agrotechnical levels on weed infestation in crops of naked and husked varieties of oat (Avena sativa L.

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    Sylwia Andruszczak

    2012-12-01

    Full Text Available The present study was carried out in the period 2007- 2009 in the Experimental Farm in Bezek near the city of Chełm. The aim of the investigation was to compare weed infestation of the husked (Krezus and naked (Cacko oat cultivars cultivated under conditions of different weed control treatments. The following weed control levels were compared: A - control object; B - harrowing twice; C - application of the herbicide Mustang 306 SE; D - herbicide Mustang 306 SE + foliar fertilizer Insol 3; E - herbicide Mustang 306 SE + two foliar fertilizers: Insol 3 and FoliCare 18:18:18. The husked oat cv. Krezus was more competitive against weeds. Number of dicotyledonous weeds and of monocotyledonous weeds, total weeds, and air-dry weight of above-ground parts of weeds in the crop of this cultivar were all significantly lower compared to the naked cv. Cacko. From the group of dicotyledonous species, Chenopodium album, Galinsoga parviflora, Matricaria maritima ssp. inodora, Polygonum aviculare, and Stellaria media were the dominant species in the crops of the oat varieties under investigation, whereas among the monocotyledonous species Echinochloa crus-galli, Setaria pumila, Apera spica-venti, and Elymus repens occurred in greatest numbers. The application of the herbicide Mustang 306 SE decreased the number of dicotyledonous weeds and air-dry weight of weeds, compared to the treatment in which mechanical weed control had been used.

  8. Phytotoxic effects of Cerbera manghas L. leaf extracts on seedling elongation of four monocot and four dicot test species

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    Ichsan Nurul Bari

    2017-09-01

    Full Text Available Exploration of allelochemicals with phytotoxic effects is intended to minimize a current dependency on synthetic herbicides in weed management. Several allelochemicals from the tropical tree Cerbera manghas (sea mango have been reported as termiticides and bactericides. The present study investigated possible phytotoxic effects of C. manghas leaf extracts under laboratory conditions. Four monocots: barnyard grass (Echinochloa crus-galli, foxtail fescue (Vulpia myuros, Italian ryegrass (Lolium multiflorum, and timothy (Phleum pratense and four dicots: alfalfa (Medicago sativa, garden cress (Lepidium sativum, lettuce (Lactuca sativa, and rapeseed (Brassica napus were used as test species. Elongation of both shoots and roots of seedlings was measured to assess any phytotoxic effects. The results showed that the sensitivities of shoots and roots were different between the test species, and the inhibition of seedling elongation significantly increased with increasing concentration of leaf extracts of C. manghas for all the test species. The IC50 (50% inhibitory concentration values showed that 8.50–32.30 and 4.26–34.67 mg dry weight equivalent extract mL−1 of C. manghas inhibited seedling elongation by 50%, for shoots and roots respectively. Isolation and identification of the phytotoxic substances from C. manghas are suggested for future investigation.

  9. Foods of breeding pintails in North Dakota

    Science.gov (United States)

    Krapu, G.L.

    1974-01-01

    Food habits of breeding pintails (Anas acuta) were studied relative to sex, land use, and reproductive condition during the spring and summer of 1969, 1970, and 1971 in eastern North Dakota. Hens and drakes, respectively, consumed 79.2 percent and 30.0 percent animal matter on nontilled wetlands and consumed 16.6 percent and 1.1 percent animal matter on tilled wetlands. Aquatic dipterans (primarily larval forms), snails, fairy shrimp, and earthworms accounted for 71 percent of the diet of hens on nontilled wetlands, while barnyard grass (Echinochloa crusgalli) seeds formed 71 percent of the diet of hens on tilled wetlands. Cereal grain seeds formed 84 percent of the diet of 10 hens feeding on cropland. The diet of hens was influenced by reproductive status. Animal foods were predominant during the laying period (77.1 percent) but were less important in the postlaying diet (28.9 percent). Invertebrates formed 83.9 percent of the diet of renesting hens, 61.0 percent were dipteran larvae and snails. High consumption of animal foods during egg formation presumably is related to invertebrates being superior to plants in providing certain nutrients required for production of viable eggs. Research findings suggest that food requirements of prairie-nesting pintails can be met most effectively by providing pairs access to shallow, nontilled wetland habitat subject to periodic drawdowns.

  10. Eutrophication increases methane emission to the atmosphere in tropical lagoons: insights from two Ivory Coast sites

    Science.gov (United States)

    José-mathieu Koné, Yéfanlan; Vieira Borges, Alberto

    2017-04-01

    Eutrophication increases methane emission to the atmosphere in tropical lagoons: insights from two Ivory Coast sites. Y J M Koné (1) & A.V. Borges (2) (1) Centre de recherches océanologiques (CRO) d'Abidjan, (Ivory Coast) (2) University of Liège, Chemical Oceanography Unit, Liège, Belgium (Belgium) Eutrophication is a worldwide environmental problem and a definitive solution is far from being achieved, despite the large number of studies documenting its causes. In small aquatic ecosystems, excessive growth of macrophytes is a well known undesirable consequence of eutrophication. When these plants die and sink to the bottom the decomposing biomass depletes oxygen content in the water column thus leading to anoxia promoting methane (CH4) production. Here, we reported the CH4 data obtained during six campaigns covering the annual cycle in two small lagoons of Ivory Coast (Ono, Kodjoboué) that are contrasted in the degree of eutrophication and the corresponding coverage of macrophytes (e.g. Echinochloa pyramidalis, Eichhornia crassipes, Hydrilla verticillata). Our data showed a high spatio-temporal variability of CH4 within the lagoons and between the two systems, with CH4 concentrations in surface waters ranging between 80 to 74,604 nmol L-1. The highest CH4 concentration values were observed in the eutrophic Ono lagoon that is covered by 80% of macrophytes, suggesting that lagoons dominated by macrophytes are significant sources of CH4 toward the atmosphere.

  11. True metabolizable energy of moist-soil seeds

    Science.gov (United States)

    Checkett, J.M.; Drobney, R.D.; Petrie, M.J.; Graber, D.A.

    2002-01-01

    Habitat objectives for migrating and wintering waterfowl are often established by converting population energy demands into an equivalent measure of foraging habitat. In some areas, seeds produced from moist-soil plants provide a significant proportion of the energy available to waterfowl. To accurately establish habitat objectives for migrating and wintering waterfowl, managers must estimate seed production from moist-soil plants and have information on metabolizable energy (ME) of moist-soil seeds. Although methods for estimating seed production have been developed, ME has been determined for few natural seeds. We determined true metabolizable energy (TME) of 10 moist-soil seeds commonly consumed by wintering and migrating ducks. TME estimates were similar (P>0.05) for hairy crabgrass (Digitaria sanguinalis; 3.09 kcal/g), little hairy crabgrass (D. ischaemum; 3.10 kcal/g), pigweed (Amaranthus spp.; 2.97 kcal/g), yellow foxtail (Setaria lutescens; 2.88 kcal/g), fall panicum (Panicum dichotomiflorum; 2.75 kcal/g), curly dock (Rumex crispus; 2.68 kcal/g), and wild millet (Echinochloa crusgalli; 2.61 kcal/g), but less (P<0.05) for beakrush (Rynchospora corniculata; 1.86 kcal/g), paspalum (Paspalum laeve; 1.57 kcal/g), and nodding or curltop ladysthumb smartweed (Polygonum lapathifolium; 1.52 kcal/g). TME values determined for moist-soil seeds in this study will allow managers to accurately estimate carrying capacity of waterfowl habitats.

  12. Air-borne Contact Dermatitis in Varanasi

    Directory of Open Access Journals (Sweden)

    K K Singh

    1986-01-01

    Full Text Available Forty-six patients suspected to have air borne contact dermatitis were tested with various plant antigens. Thirteen patients turned out to be sensitive to one or more antigens. The plant antigens, used for testing, were Parthenium hysterophorus, Lantana camara, Cynodon dactylon, Bougainvaled spectabills, calotropis procera, Argimone mexicana, Acacia arabica, Azadiracha indica, Eucalyptus rostrata, Saraka indica, triticum vulgare, Triticum aestivum, Dryopteris filix, Nerium indicum, Eclipta alba, Mangifera indica, Trianthema monogyna, Euphorbia hirta, Euphorbia thimifolia, Amaranthus spinosus, Amaranthus viridis, Carissa carands, Salvia plebia, Cyperus rotandus, Cassia occidentalis, Gynandropsis gynandra, Pennisetum typhoides, chenopodium album, Nicotana tobacum, Tagetes sp, Rosa indica, Cestrum nocturnum, Helianthus annus, Jasminum samlae, Thuja orientalis, Cajanus cajan, Hibiscus rosasinensis, Echinochloa cruss-galli, Phaseolus aureus, Ricinus communis and Alternantheria sessilis. The maximum positive reactions were elicited by Parthenium hysterophorus (30.0% followed in the order of frequency by Amarnthus viridis (10.0% Gynandropsis gynandra (10.0% Pennisetum typhoides (10.0%, Nerium indicum (3.9%, Triticum vulgare (2.5% and Dryopteris filix (2.5%. Rest of the plant antigens did not show any reaction. The male to female ratio was 5.5:1.

  13. A study on compatibilities on transgenic herbicide-resistant rice with wild relatives by using autoradiography of 32P labeled pollen

    International Nuclear Information System (INIS)

    Liu Linli; Qiang Sheng; Song Xiaoling

    2004-01-01

    To evaluate the possibility of gene flow through observation of the sexual compatibilities of transgenic herbicide-resistant rice with wild relative by using isotope tracer to label pollen grains, the experiments on radioactivity, tracer mode, autoradiography film and time were conducted. Better procedure was to label pollen grains of transgenic herbicide-resistant rice by culturing the rice in a 1.48 x 10 7 Bq/L 32 P nutrient liquid, to pollinate the labelled pollen grains on the stigmas of barnyard grass (Echinochloa crusgalli var. mitis), Oryza officinalis and weedy rice (Oryza sativa) respectively, and then 3 hour later, to fix these pistils on a piece of glass plate and cover the film of Luck 400 on it for autoradiography. The autoradiographs show that the tube of the transgenic rice's pollens cannot penetrate the stigma of barnyard grass and arrive at embryo sacs to fertilize, so that the possibility of gene flow between them is the lowest; the tube of the labelled pollens can penetrate the stigma of O officinalis and enter the style but can not arrive at embryo sacs to fertilize, so the possibility of gene flow between them is relatively low; and the pollen tube can arrive at the embryo sacs of the weedy rice, so that the possibility of gene flow is relatively high from transgenic herbicide-resistant rice to weedy rice. (authors)

  14. Chemical control of perennial and annual weeds in herbicide resistant soybean crops.

    Science.gov (United States)

    Sarpe, N; Roibu, C; Negrila, E; Bodescu, F; Fuia, S; Popa, C; Beraru, C

    2001-01-01

    In Romania, the first tests with Roundup Ready on soybean crops were performed in 1998, on 2 soil types: a) at Teleorman Station on chernozem containing 3.5% humus, 4.5% clay b) at Brăila Station placed in Danube Meadow on alluvial soil containing 3.90% humus and 46% clay. In every locality cultivated soybean cultivar S.2254 was resistant to glyphosate. During the three years of experiments (1998-2000) the crop of soybean was infested with various species of weeds (both annual and perennial) of which the most important are: Sorghum halepense (60-80%), Echinochloa crus-galli, Setaria glauca, Amaranthus retroflexus, Solarium nigrum, Yanthium italicum, Abutilon theoprasthi, Sinapis arvensis, Datum stramonium, Polygonum persicaria, Calystegia sepium, Cirsium arvense. In 3 years of experience the best weed control and the highest soybean production were obtained in the variants treated 2 times postemergent with Roundup Ready at a dose of 3 + 3 l/ha. Similar results were also obtained in the farms of the Academy of Agricultural Forestry Sciences, where GMO soybean was cultivated on 1500 hectares.

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

    Science.gov (United States)

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

    2006-09-01

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

  16. Genetic diversity and genomic resources available for the small millet crops to accelerate a New Green Revolution.

    Science.gov (United States)

    Goron, Travis L; Raizada, Manish N

    2015-01-01

    Small millets are nutrient-rich food sources traditionally grown and consumed by subsistence farmers in Asia and Africa. They include finger millet (Eleusine coracana), foxtail millet (Setaria italica), kodo millet (Paspalum scrobiculatum), proso millet (Panicum miliaceum), barnyard millet (Echinochloa spp.), and little millet (Panicum sumatrense). Local farmers value the small millets for their nutritional and health benefits, tolerance to extreme stress including drought, and ability to grow under low nutrient input conditions, ideal in an era of climate change and steadily depleting natural resources. Little scientific attention has been paid to these crops, hence they have been termed "orphan cereals." Despite this challenge, an advantageous quality of the small millets is that they continue to be grown in remote regions of the world which has preserved their biodiversity, providing breeders with unique alleles for crop improvement. The purpose of this review, first, is to highlight the diverse traits of each small millet species that are valued by farmers and consumers which hold potential for selection, improvement or mechanistic study. For each species, the germplasm, genetic and genomic resources available will then be described as potential tools to exploit this biodiversity. The review will conclude with noting current trends and gaps in the literature and make recommendations on how to better preserve and utilize diversity within these species to accelerate a New Green Revolution for subsistence farmers in Asia and Africa.

  17. Studies on weed diversity and its associated phytosociology under direct dry seeded rice systems

    Directory of Open Access Journals (Sweden)

    Mantosh Kumar Sinha

    2016-10-01

    Full Text Available Chhattisgarh is commonly known as Bowl of rice where rice is grown as monocrop in the entire state whether soil is bhata, matasi, kanhar or black soil. Present study is based on the study of biodiversity of weeds under Direct Dry Seeded Rice Systems in Koria District (C.G. Study was conducted to assess the phytosociological studies of weed species in paddy field at Baikunthpur, Koriya district, Chattisgarh. A total of 43 genera and 9 families of Dicotyledonae and 3 families of monocots and 1 Pteridophytes was also observed and 43 weed species were identified Ratio of Sedges: (Grasses:Broad-leaved weeds was calculated as 9:12:18 Ratio under direct dry seeded rice systems. The results obtained indicated that Echinochloa colona, Cyperus iria and Cynodon dactylon were the most frequent in 2007; E. colona and C. iria were the most frequent in 2008 and 2009. The importance value index (IVI revealed that the most important weeds within the community were Poaceae and Cyperaceae. Out of 12 angiosperm families the predominance was shown by monocot families Cyperaceae and Poaceae having and weed species, respectively. The pteridophyta family Marsileaceae was represented by 1 weed species.

  18. Synthesis, biological activities and SAR studies of new 3-substitutedphenyl-4-substitutedbenzylideneamino-1,2,4-triazole Mannich bases and bis-Mannich bases as ketol-acid reductoisomerase inhibitors.

    Science.gov (United States)

    Wang, Bao-Lei; Zhang, Li-Yuan; Liu, Xing-Hai; Ma, Yi; Zhang, Yan; Li, Zheng-Ming; Zhang, Xiao

    2017-12-15

    A series of new 3-substitutedphenyl-4-substitutedbenzylideneamino-1,2,4-triazole Mannich bases and bis-Mannich bases were synthesized through Mannich reaction with high yields. Their structures were confirmed by means of IR, 1 H NMR, 13 C NMR and elemental analysis. The preliminary bioassay indicated that compounds 7g, 7h and 7l exhibited potent in vitro inhibitory activities against ketol-acid reductoisomerase (KARI) with K i value of (0.38 ± 0.25), (6.59 ± 2.75) and (8.46 ± 3.99) μmol/L, respectively, and were comparable with IpOHA. They could be new KARI inhibitors for follow-up research. Some of the title compounds also exhibited obvious herbicidal activities against Echinochloa crusgalli and remarkable in vitro fungicidal activities against Physalospora piricola and Rhizoctonia cerealis. The SAR of the compounds were analyzed, in which the molecular docking revealed the binding mode of 7g with the KARI, and the 3D-QSAR results provided useful information for guiding further optimization of this kind of structures to discover new fungicidal agents towards Rhizoctonia cerealis. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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    Paula Novaes

    2012-12-01

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

  20. Phytotoxic effects of aqueous leaf extracts of four Myrtaceae species on three weeds

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    Maristela Imatomi

    2015-05-01

    Full Text Available Research on allelopathic interactions can be useful in the search for phytotoxins produced by plants that may be employed as natural herbicides. The aim of this study was to assess the phytotoxic action of aqueous leaf extract of Blepharocalyx salicifolius, Myrcia multiflora, Myrcia splendens and Myrcia tomentosa on the germination and development of three weeds. The working hypothesis was that leaf extracts of Myrtaceae may negatively influence the development of weed species. Aqueous leaf extracts at 5 and 10% (g mL-1 were tested on the germination and growth of Euphorbia heterophylla, Echinochloa crus-galli and Ipomoea grandifolia and compared with the herbicide oxyfluorfen and distilled water (control. The most extracts caused pronounced delays in seed germination and inhibited the growth of seedlings of E. heterophylla; I. grandifolia and E. crus-galli, with the last target species had no growth shoot inhibited by the extracts. In this study, the potential and efficiency of the tested aqueous leaf extracts were evident because they were more phytotoxic to the weeds than the herbicide. Thus, the aqueous extracts of leaves from Myrtaceae species show potential for the isolation of active compounds that can be used for the production of natural herbicides in the future.

  1. [Effects of different multiple cropping systems on paddy field weed community under long term paddy-upland rotation].

    Science.gov (United States)

    Yang, Bin-Juan; Huang, Guo-Qin; Xu, Ning; Wang, Shu-Bin

    2013-09-01

    Based on a long term field experiment, this paper studied the effects of different multiple cropping systems on the weed community composition and species diversity under paddy-upland rotation. The multiple cropping rotation systems could significantly decrease weed density and inhibited weed growth. Among the rotation systems, the milk vetch-early rice-late maize --> milk vetchearly maize intercropped with early soybean-late rice (CCSR) had the lowest weed species dominance, which inhibited the dominant weeds and decreased their damage. Under different multiple cropping systems, the main weed community was all composed of Monochoia vaginalis, Echinochloa crusgalli, and Sagittaria pygmae, and the similarity of weed community was higher, with the highest similarity appeared in milk vetch-early rice-late maize intercropped with late soybean --> milk vetch-early maize-late rice (CSCR) and in CCSR. In sum, the multiple cropping rotations in paddy field could inhibit weeds to a certain extent, but attentions should be paid to the damage of some less important weeds.

  2. Environment and Host Affects Arbuscular Mycorrhiza Fungi (AMF) Population.

    Science.gov (United States)

    Rahim, Norahizah Abd; Jais, Hasnah Md; Hassan, Hasnuri Mat

    2016-11-01

    The association of arbuscular mycorrhiza fungi (AMF) and roots undoubtedly gives positive advantages to the host plant. However, heavily fertilised soil such as in oil palm plantation, inhibit the growth of mycorrhiza. Thus, the aim of this research is to distinguish and quantify the availability of AMF population and propagules at different sites of an oil palm plantation by Most Probable Number (MPN) assay. In addition, root infection method was employed to observe host compatibility through the propagation of AMF using two different types of hosts, monocotyledon ( Echinochloa cruss-galli ) and dicotyledon ( Vigna radiata ). Three different locations at an oil palm plantation were chosen for sampling. Each location was represented by a distinctive soil series, and were further divided into two sites, that is canopy and midway area. Midway site had a greater population of AMF compared to canopy. The result showed that different environments affect the availability of AMF in the soil. Higher number of AMF infection observed in monocotyledon host suggests that the fibrous root system provide a better association with mycorrhiza.

  3. Evaluation of special, functional and structural diversity of weeds community in pistachios (Pistacia vera L. orchards of Bardaskan County

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    S. Elahi

    2016-04-01

    Full Text Available To study weed species diversity and community structure in pistachio (Pistacia vera L. orchards in 33 orchards of 12 villages an investigation was conducted in Bardaskan County, Khorasan Razavi Province, Iran during 2008-2009. Weed population sampling was conducted in a w shape method using 1m² quadrate. The results showed that the weeds of pistachio orchards were belonging to 15 families and 44 species. dicotyledons (31 species were more than monocotyledons (13 species. Such as in this community, weed species of C3, C4, annual and perennial were 26, 18, 28 and 13, respectively. The majority of weed species were belonging to the plant families of chenopodiceae (9 species and poaceae (12 species amongst dicotyledons and monocotyledons, respectively. the most important species of monocotyledon annual weeds were including Echinochloa crus-gali, Digitaria sanguinlis, Setaria viridis and perennial weeds were including Cyperus routundus, Cynodon dactylon and convolvulus arvensis. Weed species were grouped in seven clusters for density average, frequency and uniformity (similarity 75 percent whereas in eight clusters for relative density average, relative frequency and relative uniformity (similarity 75 percent. Amplitude changes of Shannon-winter diversity index were between 2.3 and 0.16 and of Simpson dominant index were between 0.97 and 0.17. The difference among indices of biodiversity and dominant clusters were relative to scale and type of management practices.

  4. Application of electrical capacitance measurement for in situ monitoring of competitive interactions between maize and weed plants

    Energy Technology Data Exchange (ETDEWEB)

    Cseresnyés, I.; Takács, T.; Füzy, A.; Végh, K.R.; Lehoczky, E.

    2016-11-01

    Applicability of root electrical capacitance (EC) measurement for monitoring of crop–weed competition was studied in a pot experiment. Maize (Zea mays L.) was grown both alone and with Echinochloa crus-galli or Abutilon theophrasti in different densities with regular measurement of root EC. Plants were harvested 42 days after planting to determine above- and belowground biomass. Depending on weed density, E. crus-galli-A. theophrasti interaction reduced the root EC of maize by 22–66% and 3–57%, respectively. Competitive effect of crop on weeds and intraspecific competition among weeds could also be detected by EC values: E. crus-galli was less sensitive both to the presence of maize and to intraspecific competition than A. theophrasti. Strong linear correlations between root dry mass and root EC for crop and weeds (with R2 from 0.901 to 0.956) were obtained by regression analyses at the end of the experiment. EC monitoring informed us on the emergence time of competition: E. crus-galli interfered with maize root growth a week earlier then A. theophrasti, and increasing weed densities accelerated the emergence of competition. In conclusion, the simple, non-destructive EC method should be considered a potential in situ technique for pot studies on crop–weed competition, which may partially substitute the intrusive techniques commonly used in agricultural researches. (Author)

  5. Weed infestation of field crops in different soils in the protective zone of Roztocze National Park. Part II. Root crops

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    Marta Ziemińska-Smyk

    2013-12-01

    Full Text Available The study on weed infestation of root crops in different soils in the protective zone of Roztocze National Park was conducted in the years 1991-1995. As many as 240 phytosociological records, made with the use of Braun-Blanquet method, were taken in potato and sugar beet fields. The number of weed species in sugar beet and potato in the area depended on the soil and type of root crop. In the same environment conditions. the iiuinber of weed species was higher in potato than in sugar beet. The most difficult weed species iii all types of soil were: Chenopodium album, Stellaria media and Convolvulus arvensis. Podsolic soils were highly infested by two acidophylic species: Spergula arvensis and Raphanus raphanistum. Potato in loess soil and brown soil made of loamy sands were highly infested by Echinochloa crus-galli, Equisetum arvense and Galinsoga parviflora. Root crop plantations in brown soils formed from gaizes of granulometric loam texture and limestone soils were infested by: Galium aparine, Sonchus arvensis, Sinapis arvensis and Veronica persica.

  6. State of weed infestation and features of sugar beet protection in Belarus

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    Soroka Sergey Vladimirovich

    2006-01-01

    Full Text Available The changes of phytosanitary situation recently taking place in sugar beet crops in the Republic of Belarus are shown. It is noticed that in the crop agrocoenosises there is a high infestation level caused by Japanese barnyard millet (Echinochloa crus-galli (L Pal. Beauv, field sowthistle (Sonchus arvensis L, chickweed (Stellaria media (L Vill, quick grass (Agropyron repens (L Pal Beauv, matricary (Matricaria perforate Merat, creeping thistle (Circium arvense (L scop, marsh woundwort (Stachus palustris L wild buckwheat (Polygonum convolvulus L, bristle stem hemp nettle (Galeopsis tetrahit L, common horsetail (Equisetum arvense L, field forget-me-not (Myosotis arvensis (L Hill, shepherd's purse (Capsella bursa-pastoris (L Med etc. Due to non-observance of preventive and separate agrotechnical techniques especially in spring-summer period, such weeds as bedstraw (Galium aparine L, white campion (Melandrium album (Mill Garcke, green amaranthus (Amaranthus retroflexus L started to appear in the crops. To protect sugar beet effectively, two variants of herbicides application are proposed. The first one - a combined, one stipulating soil action herbicides application before planting or before sugar beet seedlings emergence and on seedlings - to carry out two treatment by post-emergence preparations. The second variant, a split post- -emergence herbicide application (two-three times spraying on growing weeds at small application rates. In the next 5-6 years, a combined method will be of a primary importance in the conditions of the Republic.

  7. Characterization of the Weed Seed Bank in Zero and Conventional Tillage in Central Chile Caracterización del Banco de Semillas de Malezas en Labranza Cero y Convencional en Chile Central

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    Rosa Peralta Caroca

    2011-03-01

    Full Text Available We studied the abundance, species composition, and depth distribution of the weed seed bank under no-tillage (NT and conventional tillage (CT at two sites, A and B. Soil samples were taken at three soil depths (0-2, 2-5, and 5-15 cm. Germinated, dormant, and total seeds were counted. The total number of seeds was higher (p ≤ 0.05 under CT treatment at the two sites (CTA = 5175 seeds m-2, NTA = 3250 seeds m-2, CTB = 33770 m-2, and NTB = 22437 seeds m-2. The number of viable, dormant, and germinated seeds was also higher (p ≤ 0.05 in CT at the two sites. The percentage of viable seeds was low with 37% (CTA, 34% (CTB, 21% (NTA, and 8% (NTB. Viable seeds of Chenopodium album L. (CHEAL dominated in the two trials with 67% (CTA, 20% (NTA, 96% (CTB, and 77% (NTB. In a principal component analysis, PC1 separated viable seeds of weed species according to tillage and PC2 separated weed species according to sites. Poa annua L. was the most important species associated with NT followed by Cichorium intybus L., and Sonchus while Euphorbia helioscopia L. and Echinochloa crus-galli (L. P. Beauv. were associated with CT.Se estudió la abundancia, composición de especies y distribución en profundidad del banco de semilla de maleza en labranza convencional (CT y cero labranza (NT en dos sitios, A y B. Se tomaron muestras a tres profundidades de suelo (0-2, 2-5 y 5-15 cm. Se contaron semillas germinadas, dormantes y totales. La cantidad total de semillas fue significativamente mayor (p ≤ 0,05 para ambos sitios (CTA = 5175 semillas m-2, NTA = 3250 semillas m-2, CTB = 33770 semillas m-2 y NTB = 22437 semillas m-2. La cantidad de semillas viables, dormantes y germinadas fue significativamente mayor (p ≤ 0.05 para ambos ensayos en CT que en NT. La mayor proporción de las semillas viables correspondió a germinadas. Se observó un bajo porcentaje de semillas viables 37% (CTA, 34% (CTB, 21% (NTA and 8% (NTB. Las semillas viables de Chenopodium album L. (CHEAL

  8. Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?

    Science.gov (United States)

    Veiga, Rita S. L.; Jansa, Jan; Frossard, Emmanuel; van der Heijden, Marcel G. A.

    2011-01-01

    Background Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. Methodology/Principal Findings First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between −22 and −35%). In a subsequent experiment, we selected three of the negatively responding weed species – Echinochloa crus-galli, Setaria viridis and Solanum nigrum – and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Conclusions/Significance Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions. PMID

  9. Weed infestation of winter wheat (Triticum aestivum L. under the conditions of application of some retardants

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    Elżbieta Harasim

    2013-07-01

    Full Text Available A field study was conducted in the period 2004–2007 on grey-brown podzolic soil (sandy. This study analysed the relationship between the use of stem shortening in cereals by means of retardants with the following active substances: chlormequat chloride (Antywylegacz Płynny 675 SL, trinexapac-ethyl (Moddus 250 EC, chlormequat chloride + ethephon (Cecefon 465 SL, and weed infestation. The retardants were applied at the 1st node stage (BBCH 31 – Antywylegacz Płynny 675 SL and the 2nd node stage of winter wheat (BBCH 32 – Moddus 250 EC and Cecefon 465 SL, together with the adjuvant Atpolan 80 EC (75% of SN 200 mineral oil or without the adjuvant. Winter wheat, cv. 'Muza', was grown after vetch grown for seed. The whole experiment was sprayed with the herbicides Apyros 75 WG and Starane 250 EC at the full tillering stage (BBCH 29–30. Plots where no growth regulators were used were the control treatment. Weed density and biomass showed great variation between years. In the winter wheat crop, Veronica persica, Viola arvensis, Veronica arvensis, Capsella bursa-pastoris,and Chenopodium album dominated in the dicotyledonous class, whereas Apera spica-venti, Echinochloa crus-galli,and Elymus repens were predominant among monocotyledonous plants. The level of weed infestation of the winter wheat crop, as measured by the number and air-dry weight of weeds, was significantly differentiated by years and retardants used as well as by interactions of these factors. The adjuvant Atpolan 80 EC did not have a significant effect on the above-mentioned weed infestation parameters. .

  10. Composición de la dieta de otoño del pato mexicano (Anas diazi en el vaso sur de las ciénegas del Lerma, Estado de México Fall diet composition of Mexican duck (Anas diazi at Lerma marsh, South Vessel, México State

    Directory of Open Access Journals (Sweden)

    David Colón-Quezada

    2009-04-01

    Full Text Available Se estudió la composición de la dieta del pato mexicano (Anas diazi y su variación en 2 periodos de otoño consecutivos (2004-2005 en el vaso sur de las ciénegas del Lerma, Estado de México, a partir de 24 muestras de patos cazados. El análisis complementario del peso seco agregado y la frecuencia mostraron que durante el otoño el pato mexicano tiene una dieta vegetariana en la que predominan las semillas de plantas acuáticas, malezas, maíz y tubérculos de Sagittaria y un mínimo consumo de invertebrados. Los alimentos que principalmente se consumieron en 2004 fueron semillas de Echinichloa holciformis, Polygonum lapathifolium y P. punctatum, en tanto que en la dieta de 2005, fueron semillas de maíz y tubérculos de Sagittaria macrophylla. El análisis de similitud de dietas de Sorensen, evidenció una variación de 70% entre los 2 años, lo cual puede atribuirse a la disponibilidad anual de alimento.The Mexican duck's diet composition and its variation in 2 consecutive fall periods (2004-2005 was studied at the Lerma marsh, South Basin, Mexico State, including 24 esophageal samples obtained during the hunting season. A complementary analysis using aggregated dry weight and frequency of occurrence showed than the Mexican duck has a vegetarian diet dominated by aquatic plants seeds, weeds seeds, corn seeds and Sagittaria tubes. The main foods in 2004 were Echinochloa holciformis, Polygonum lapathifolium and P. punctatum seeds, whereas corn seeds and Sagittaria macrophylla tubers dominated the 2005 diet. The Sorensen similarity analysis of the diets showed a diet variation of 70% on both years, which could be to attributed to annual food availability.

  11. Pharmacologic inhibition of autophagy sensitizes human acute leukemia Jurkat T cells to acacetin-induced apoptosis.

    Science.gov (United States)

    Lee, Ji Young; Jun, Do Youn; Kim, Ki Yun; Ha, Eun Ji; Woo, Mi Hee; Ko, Jee Youn; Yun, Young Ho; Oh, In-Seok; Kim, Young Ho

    2016-11-04

    Exposure of Jurkat T cell clone (J/Neo cells) to acacetin (5,7-dihydroxy-4'-methoxyflavone), which is present in barnyard millet [Echinochloa esculenta (A. Braun)] grains, resulted in cytotoxicity, accumulation of apoptotic sub-G1 cells, Bak activation, loss of mitochondrial membrane potential (Δψm), activation of caspase-9 and caspase-3, cleavage of poly (ADP-ribose) polymerase (PARP), and FITC-Annexin V-stainable phosphatidylserine exposure on the external surface of the cytoplasmic membrane without accompanying necrosis. These apoptotic responses were completely abrogated in Jurkat T cell clone (J/Bcl-xL) overexpressing Bcl-xL. Under these conditions, cellular autophagic responses, including suppression of the Akt-mTOR pathway and p62/SQSTM1 down-regulation, were detected both J/Neo and J/Bcl-xL cells; however, formation of acridine orange-stainable acidic vascular organelles, LC3-I/II conversion, and Beclin1 phosphorylation (Ser-15) were detected only in J/Neo cells. Correspondingly, concomitant treatment with the autophagy inhibitor (3-methyladenine or LY294002) appeared to enhance acacetin-induced apoptotic responses, such as Bak activation, Δψm loss, activation of caspae-9 and caspase-3, and apoptotic sub-G1 accumulation. This indicated that acacetin could induce apoptosis and cytoprotective autophagy in Jurkat T cells simultaneously. Together, these results demonstrate that acacetin induces not only apoptotic cell death via Bak activation, Δψm loss, and mitochondria-dependent activation of the caspase cascade, but also cytoprotective autophagy resulting from suppression of the Akt-mTOR pathway. Furthermore, pharmacologic inhibition of the autophagy pathway augments Bak activation and resultant mitochondrial damage-mediated apoptosis in Jurkat T cells.

  12. Can arbuscular mycorrhizal fungi reduce the growth of agricultural weeds?

    Directory of Open Access Journals (Sweden)

    Rita S L Veiga

    Full Text Available BACKGROUND: Arbuscular mycorrhizal fungi (AMF are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. METHODOLOGY/PRINCIPAL FINDINGS: First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between -22 and -35%. In a subsequent experiment, we selected three of the negatively responding weed species--Echinochloa crus-galli, Setaria viridis and Solanum nigrum--and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum. Finally, we tested whether the presence of a crop (maize enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. CONCLUSIONS/SIGNIFICANCE: Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field

  13. Efecto de la cobertura de rastrojos en la germinación del arroz (Oryza sativa L. y principales malezas asociadas

    Directory of Open Access Journals (Sweden)

    Yemel M. Ortega

    2005-01-01

    Full Text Available Efecto de la cobertura de rastrojos en la germinacióndel arroz (Oryza sativaL. y principales malezas asociadas. Para determinar el grado de interferencia causado por distintas cantidades de rastrojos de arroz (Oryza sativaL. sobrela emergencia de arroz y malezas asociadas al cultivo, en el2003 se realizaron tres experimentos simultáneos en la hacienda el Pelón de la Bajura, Guanacaste, Costa Rica. Se aplicaron nueve tratamientos (0 a 9 t/ha de coberturas con rastrojosde la variedad de arroz CR 1113 para medir los efectos en laemergencia del arroz y malezas. Las malezas asociadas incluyen las más frecuentes en agroecosistemas arroceros inundados: Oryza sativa, Echinochloa colona, Cyperusspp., Fim-bristylisspp., Ludwigiaspp. y Heteranthera limosa. En losprimeros dos experimentos se determinaron relaciones inversas entre el grado de cobertura y la densidad de plántulas demalezas emergidas (R2>0,89, y entre el grado de cobertura yel porcentaje de germinación del arroz (R2=0,86, respectivamente. Usando coberturas con rastrojos de frijol (Phaseolusvulgaris en el tercer experimento, no se observó efecto supresor en la germinación del arroz, probablemente debido a supronta descomposición. Aunque la germinación del arroz nose afectó aún a las intensidades más altas de rastrojos evaluadas, conviene realizar pruebas similares a largo plazo para determinar posibles efectos debidos a la descomposición de residuos, alelopatía y acarreo de herbicidas después de variosciclos consecutivos del cultivo de arroz.

  14. Enterobacter sp. I-3, a bio-herbicide inhibits gibberellins biosynthetic pathway and regulates abscisic acid and amino acids synthesis to control plant growth.

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Park, Jae-Man; Lee, In-Jung

    2016-12-01

    Very few bacterial species were identified as bio-herbicides for weed control. The present research was focused to elucidate the plant growth retardant properties of Enterobacter sp. I-3 during their interaction by determining the changes in endogenous photosynthetic pigments, plant hormones and amino acids. The two bacterial isolates I-4-5 and I-3 were used to select the superior bacterium for controlling weed seeds (Echinochloa crus-galli L. and Portulaca oleracea L.) germination. The post-inoculation of I-3 (Enterobacter sp. I-3) significantly inhibited the weeds seed germination than their controls. The mechanism of bacterium induced plant growth reduction was identified in lettuce treated with I-3 bacterium and compared their effects with known chemical herbicide, trinexapac-ethyl (TE). The treatment of I-3 and TE showed a significant inhibitory effect on shoot length, leaf number, leaf length, leaf width, shoot weight, root weight and chlorophyll content in lettuce seedlings. The endogenous gibberellins (GAs) and abscisic acid (ABA) analysis showed that Enterobacter sp. I-3 treated plants had lower levels of GAs (GA 12 , GA 19 , GA 20 and GA 8 ) and GAs/ABA ratio and then, the higher level of ABA when compared to their controls. Indeed, the individual amino acids ie., aspartic acid, glutamic acid, glycine, threonine, alanine, serine, leucine, isoleucine and tyrosine were declined in TE and I-3 exposed plants. Our results suggest that the utilization of Enterobacter sp. I-3 inhibits the GAs pathway and amino acids synthesis in weeds to control their growth can be an alternative to chemical herbicides. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. Host Suitability of 32 Common Weeds to Meloidogyne hapla in Organic Soils of Southwestern Quebec

    Science.gov (United States)

    Bélair, G.; Benoit, D. L.

    1996-01-01

    Thirty-two weeds commonly found in the organic soils of southwestern Quebec were evaluated for host suitability to a local isolate of the northern root-knot nematode Meloidogyne hapla under greenhouse conditions. Galls were observed on the roots of 21 species. Sixteen of the 21 had a reproduction factor (Pf/Pi = final number of M. hapla eggs and juveniles per initial number of M. hapla juveniles per pot) higher than carrot (Pf/Pi = 0.37), the major host crop in this agricultural area. Tomato cv. Rutgers was also included as a susceptible host and had the highest Pf/Pi value of 13.7. Bidens cernua, B. frondosa, B. vulgata, Erysimum cheiranthoides, Eupatorium maculatum, Matricaria matricarioides, Polygonum scabrum, Thalictrum pubescens, Veronica agrestis, and Sium suave are new host records for M. hapla. Bidens cernua, B. frondosa, B. wulgata, D. carota, M. matricarioides, Pasticana sativa, P. scabrum, S. suave, and Thlaspi arvense sustained moderate to high galling by M. hapla and supported high M. hapla production (12.4 ≤ Pf/Pi ≥ 2.9). Capsella bursa-pastoris, Chrysanthemum leucanthemum, Gnaphalium uliginosum, Stellaria media, and Veronica agrestis sustained moderate galling and supported moderate M. hapla reproduction (2.8 ≤ Pf/Pi ≥ 0.5). Chenopodium album, C. glaucum, E. cheiranthoides, P. convolvulus, Portulaca oleracea, and Rorippa islandica supported low reproduction (0.25 ≤ Pf/Pi ≥ 0.02) and sustained low galling. Galling was observed on Senecio vulgaris but no eggs or juveniles; thus, S. vulgaris may be useful as a trap plant. Eupatorium maculatum, and T. pubescens harbored no distinct galling but supported low to moderate M. hapla reproduction, respectively. Amaranthus retroflexus, Ambrosia artemisiifolia, Echinochloa crusgalli, Erigeron canadensis, Oenothera parviflora, Panicum capillare, Setaria glauca, S. viridis, and Solidago canadensis were nonhosts. Our results demonstrate the importance of adequate weed control in an integrated program

  16. Selectivity and weed control efficacy of some herbicides applied to sprinkler irrigated rice (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Cavero, J.; Zaragoza, C.; Cirujeda, A.; Anzalone, A.; Faci, J. M.; Blanco, O.

    2011-07-01

    Sprinkler irrigation can reduce the irrigation water needed to grow rice. However, most available information on weed control with herbicides is related to flood irrigated rice because this is the main growing method. Field experiments were conducted at Zaragoza (Spain) during two years to study weed control and tolerance of sprinkler irrigated rice to several herbicides. The main weeds were Atriplex prostrata Boucher ex DC., Cyperus rotundus L., Echinochloa crus-galli (L.) Beauv. and Sonchus oleraceus L. Rice cv Guadiamar was tolerant to preemergence (PRE) application of clomazone at 0.36 kg ha{sup -}1 and oxadiazon at 0.5 kg ha{sup -}1. PRE application of pendimethalin at 1.32 kg ha{sup -}1 combined with clomazone at 0.36 kg ha{sup -}1 decreased rice yield. Postemergence (POST) application of bentazon at 1.6 kg ha{sup -}1 + MCPA at 0.25 kg ha{sup -}1 did not injure rice but POST application of azimsulfuron at 0.025 kg ha{sup -}1 produced visual crop injury. Only treatments that controlled grassy weeds since rice was planted and by more than 80% at harvest time lead to acceptable rice yield (> 5,000 kg ha{sup -}1). Clomazone applied PRE at 0.36 kg ha{sup -}1 provided good control of grassy weeds (> 80%) and the highest rice yield, so it is recommended as a selective and efficacious PRE treatment for weed control of annual weeds in sprinkler irrigated rice. The perennial purple nutsedge was difficult to control at high plant densities (> 150 plants m{sup -}2) and the recommended herbicide is azimsulfuron applied at POST at 0.02 kg ha{sup -}1. (Author) 37 refs.

  17. Ecological assessment of the macrophytes and phytoplankton in El-Rayah Al-Behery, River Nile, Egypt

    Directory of Open Access Journals (Sweden)

    Amany M. Haroon

    2017-09-01

    Full Text Available The present study aimed to assess the effect of ecological factors on distribution and species composition of macrophytes and phytoplankton communities at El-Rayah Al-Behery. Changes in the quantitative and qualitative composition of the macrophytes and phytoplankton communities were detected in relation to season and sampling site. A total of eleven macrophytes and 100 phytoplankton species were identified. Among the macrophytes, the emergent species Echinochloa stagnina was the most dominant and widely distributed. Phytoplankton community is fairly diverse, related to 7 classes, which contains 3 main classes: Bacillariophyceae (28 taxa, Chlorophyceae (33 taxa and Cyanophyceae (23 taxa. According to statistical analysis, occurrence of most macrophytes species were reversely affected by DO, COD, BOD and PO4; and closely correlated with NO2, NO3, Temp. and pH values. However, nitrogen and phosphorus are considered as limiting factors for bacillariohyceae growth (r = 0.7. Both temperature and pH have a positive effect on the growth of chlorophyceae (r = 0.9 and 0.8, respectively; while dissolved oxygen is an important parameter that affects on the growth of cyanphyceae (r = 0.8. In addition, existence of Myriophyllium spicatum was associated with increasing of bacillariohyceae and total phytoplankton density (r = 0.7. However, the presence of Polygonum tomentosum was intensely related with chlorophyceae (r = 0.9 and Potamogeton nodosus and Polygonum tomentosum were positively correlated with cyanphyceae. In conclusion, the investigated area was characterized by different taxonomic composition of macrophytes and phytoplankton communities, which varied as a result of changing in water physiochemical characteristics as well as the interaction between different species. Keywords: Ecological assessment, Phytoplankton, Macrophytes

  18. Phytotoxic Activity of Ocimum tenuiflorum Extracts on Germination and Seedling Growth of Different Plant Species

    Directory of Open Access Journals (Sweden)

    A. K. M. Mominul Islam

    2014-01-01

    Full Text Available Phytotoxic activity of Ocimum tenuiflorum (Lamiaceae plant extracts was investigated against the germination and seedling growth of cress (Lepidium sativum, lettuce (Lactuca sativa, alfalfa (Medicago sativa, Italian ryegrass (Lolium multiflorum, barnyard grass (Echinochloa crus-galli, and timothy (Phleum pratense at four different concentrations. The plant extracts at concentrations greater than 30 mg dry weight equivalent extract mL−1 reduced significantly the total germination percent (GP, germination index (GI, germination energy (GE, speed of emergence (SE, seedling vigour index (SVI, and coefficient of the rate of germination (CRG of all test species except barnyard grass and GP of lettuce. In contrast, time required for 50% germination (T50 and mean germination time (MGT were increased at the same or higher than this concentration. The increasing trend of T50 and MGT and the decreasing trend of other indices indicated a significant inhibition or delay of germination of the test species by O. tenuiflorum plant extracts and vice versa. In addition, the shoot and root growth of all test species were significantly inhibited by the extracts at concentrations greater than 10 mg dry weight equivalent extract mL−1. The I50 values for shoot and root growth were ranged from 26 to 104 mg dry weight equivalent extract mL−1. Seedling growth was more sensitive to the extracts compared to seed germination. Results of this study suggest that O. tenuiflorum plant extracts have phytotoxic properties and thus contain phytotoxic substances. Isolation and characterization of those substances from this plant may act as a tool for new natural, biodegradable herbicide development to control weeds.

  19. Comparative Genomics of Smut Pathogens: Insights From Orphans and Positively Selected Genes Into Host Specialization

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    Juliana Benevenuto

    2018-04-01

    Full Text Available Host specialization is a key evolutionary process for the diversification and emergence of new pathogens. However, the molecular determinants of host range are poorly understood. Smut fungi are biotrophic pathogens that have distinct and narrow host ranges based on largely unknown genetic determinants. Hence, we aimed to expand comparative genomics analyses of smut fungi by including more species infecting different hosts and to define orphans and positively selected genes to gain further insights into the genetics basis of host specialization. We analyzed nine lineages of smut fungi isolated from eight crop and non-crop hosts: maize, barley, sugarcane, wheat, oats, Zizania latifolia (Manchurian rice, Echinochloa colona (a wild grass, and Persicaria sp. (a wild dicot plant. We assembled two new genomes: Ustilago hordei (strain Uhor01 isolated from oats and U. tritici (strain CBS 119.19 isolated from wheat. The smut genomes were of small sizes, ranging from 18.38 to 24.63 Mb. U. hordei species experienced genome expansions due to the proliferation of transposable elements and the amount of these elements varied among the two strains. Phylogenetic analysis confirmed that Ustilago is not a monophyletic genus and, furthermore, detected misclassification of the U. tritici specimen. The comparison between smut pathogens of crop and non-crop hosts did not reveal distinct signatures, suggesting that host domestication did not play a dominant role in shaping the evolution of smuts. We found that host specialization in smut fungi likely has a complex genetic basis: different functional categories were enriched in orphans and lineage-specific selected genes. The diversification and gain/loss of effector genes are probably the most important determinants of host specificity.

  20. Interaction between C 4 barnyard grass and C 3 upland rice under elevated CO 2: Impact of mycorrhizae

    Science.gov (United States)

    Tang, Jianjun; Xu, Liming; Chen, Xin; Hu, Shuijin

    2009-03-01

    Atmospheric CO 2 enrichment may impact arbuscular mycorrhizae (AM) development and function, which could have subsequent effects on host plant species interactions by differentially affecting plant nutrient acquisition. However, direct evidence illustrating this scenario is limited. We examined how elevated CO 2 affects plant growth and whether mycorrhizae mediate interactions between C 4 barnyard grass ( Echinochloa crusgalli (L.) Beauv.) and C 3 upland rice ( Oryza sativa L.) in a low nutrient soil. The monocultures and combinations with or without mycorrhizal inoculation were grown at ambient (400 ± 20 μmol mol -1) and elevated CO 2 (700 ± 20 μmol mol -1) levels. The 15N isotope tracer was introduced to quantify the mycorrhizally mediated N acquisition of plants. Elevated CO 2 stimulated the growth of C 3 upland rice but not that of C 4 barnyard grass under monoculture. Elevated CO 2 also increased mycorrhizal colonization of C 4 barnyard grass but did not affect mycorrhizal colonization of C 3 upland rice. Mycorrhizal inoculation increased the shoot biomass ratio of C 4 barnyard grass to C 3 upland rice under both CO 2 concentrations but had a greater impact under the elevated than ambient CO 2 level. Mycorrhizae decreased relative interaction index (RII) of C 3 plants under both ambient and elevated CO 2, but mycorrhizae increased RII of C 4 plants only under elevated CO 2. Elevated CO 2 and mycorrhizal inoculation enhanced 15N and total N and P uptake of C 4 barnyard grass in mixture but had no effects on N and P acquisition of C 3 upland rice, thus altering the distribution of N and P between the species in mixture. These results implied that CO 2 stimulation of mycorrhizae and their nutrient acquisition may impact competitive interaction of C 4 barnyard grass and C 3 upland rice under future CO 2 scenarios.

  1. Peculiarities of Japanese millet growing on radionuclide contaminated territories

    International Nuclear Information System (INIS)

    Sedukova, G.V.; Samusev, A.M.; Yurchenko, N.V.

    2010-01-01

    In the conditions of the Republic of Belarus on the lands polluted with radionuclides there were presented results of field experiments directed to study of the influence of mineral fertilizers on the yield, 137Cs and 90Sr transfer parameters, and economical viability of Indian barnyard millet or Japanese millet (Echinochloa frumentacea) growing. There were three variants of the test: control variant (without any fertilizers), variants with entering of N70P40K80 and N90P60K100 kg/ha. Research results showed that entering of N70P40K80 increased Japanese millet yield till 450-500 c/ha. Maximum productivity of green mass, minimum radionuclide transfer factors and the highest profitability were after application of entering of N70P60K100. Entering of N90K60K100 increased the green mass yield in phase of heads appearing in 80 c/ha, in milk-wax stage – in 53 c/ha. Zootechnical quality of millet green mass was defined. Parameters of 137Cs and 90Sr transition were 0,03 and 2,6-6,4 Bq/kg:kBq/m2 correspondingly. Contamination densities of sod-podzolic loamy soils were determined to assure regulatory clean millet green mass production to be used as fodder for milk stock in order to produce whole milk and raw milk for processing. Japanese millet green mass grown for cattle feeding with purpose of milk getting could be produced at density 90Sr pollution of 0,2 Ci/km2. Sod-podzolic sandy soils with density 90Sr pollution less 1,5Ci/km2 were suitable for getting processing milk

  2. Control ecológico de malezas mediante el uso de las propiedades alelopáticas de la flora nicaragüense: el inicio de la experiencia en Nicaragua

    Directory of Open Access Journals (Sweden)

    Carolina Vega-Jarquín

    2006-12-01

    Full Text Available LAS INTERCCIONES BIOLÓGICAS MEDIANTE SEÑALES QUÍMICAS (alelopatía tienen aplicaciones prácticas en la agricultura. Actualmente son un amplio campo de investigación agrícola de vanguardia. El Programa de Recursos Genéticos (REGEN tiene como meta efectuar estudios de bioprospección de la flora nicaragüense y, paralelamente, contribuir al desarrollo de estrategias de control biológico y manejo sostenible, orientadas a la reducción de las densidades poblacionales de arvenses problemáticas identificadas en el país. La estrategia metodológica del proyecto consta de dos grandes fases: 1 estudiar la biología y ecología de la germinación de diferentes especies de malezas; y 2 evaluar en laboratorio y, posteriormente, escalar el estudio sobre el efecto alelopático de diversas especies de la flora nicaragüense sobre arvenses reconocidas como problemáticas y de alta incidencia nacional e internacional, como Rottboellia cochinchinensis y Echinochloa colona L. Paralelamente, implementar un sistema modelo utilizando variedades apropiadas de arroz (que se cultivan en Nicaragua para los estudios de alelopatía. Resultados preliminares de los ensayos de germinación en condiciones de laboratorio, indican que los factores ambientales (humedad, temperatura y diferentes mecanismos de dormancia podrían regular la germinación y la sobrevivencia de semillas de malezas; por lo que para efectuar cualquier estudio de control ecológico de malezas, se debe profundizar en el estudio de la biología y ecología de la germinación de las especies problemáticas.

  3. Evaluación de bispiribac-sodio en el control de malezas en arroz de temporal

    Directory of Open Access Journals (Sweden)

    Valent\\u00EDn A. Esqueda

    2004-01-01

    Full Text Available Evaluación de Bispiribac-sodio en el control de malezas en arroz de temporal. Se establecieron dos experimentos en Los Naranjos, Veracruz, México, con el objeto de evaluar la eficiencia biológica y el efecto fitotóxico del herbicida postemergente bispiribac-sodio, solo y en mezcla con otros herbicidas, para controlar malezas en el cultivo de arroz de temporal. Un experimento fue establecido el 13 de junio de 1999 el segundo el 9 de junio del 2000 con arroz de la variedad Milagro Filipino, a 100 kg/ha. El diseño experimental fue de bloques completos al azar con ocho tratamientos para el primero y seis para el segundo, y cuatro repeticiones de cada uno. En 1999, el control de malezas se evaluó a los 15, 30 y 105 días después de la aplicación (DDA y en 2000 a los 15, 30 y 45 DDA. En ambos experimentos, la toxicidad se evaluó a los 15 y 30 DDA. Las especies de malezas dominantes fueron el zacate de agua [Echinochloa colona (L. Link.], el pelillo (Cyperus iria L. y el zacate frente de toro [Digitaria ciliaris (Retz. Koel]. Bispiribac-sodio afectó solamente plantas de malezas emergidas; este herbicida controló eficientemente al pelillo a 15 g/ha, al zacate de agua a 22 g/ha y solamente tuvo un control parcial del zacate frente de toro. Al mezclar el bispiribac- sodio con clomazone o tiobencarbo, se incrementó el control de los zacates y se obtuvo un efecto herbicida residual. El bispiribac-sodio fue altamente selectivo al arroz.

  4. Research on the weed control degree and glyphosate soil biodegradation in apple plantations (Pioneer variety

    Directory of Open Access Journals (Sweden)

    Ersilia ALEXA

    2010-05-01

    Full Text Available In this study we follow control degree of glyphosate herbicide on weeds in apple plantations (Pioneer variety of the Research Station Timisoara. It was also followed glyphosate biodegradation capacity in the soil by determining the amount of CO2 released by the action of microorganisms on C14 glyphosate marked isotope. Laboratory analysis of glyphosate residues in soil was made using a Liquid Scintillation TRIATHLER. Glyphosate biodegradation ability in the presence of soil microorganisms is high, so glyphosate residues remaining in soil, in terms of its use in weed combating, are minimal. Study of glyphosate biodegradation capacity in the experimental field indicates that the CO2 fraction accumulated after 50 days is 28.02% for samples exposed in the experimental field. Weather conditions, especially temperature variations between day and night, influences the activity of soilmicroorganisms and affect biodegraded glyphosate percentage.Chemical method of weed control consisted in: herbicide used was Roundup 3 l/ha (glyphosate isopropyl amine salt 360 g/l and are based on chemical application on weeds, on the rows of trees, on their uptake and translocation in their organs having as principal scope the total destruction of weeds. The experimental results obtained reveal a weed combat degree of 82.98% , in the case of chemical variant, compared with control variant. The species combated mainly due to glyphosate herbicide, which is no longer found in the final mapping are: Capsella bursa-pastoris, Chenopodium album, Echinochloa crus-galli, Plantago major, Polygonum aviculare. Total combated weeds /m2 with glyphosate is 126.67.

  5. Dynamique de la flore et de la végétation des Niayes et du Bassin arachidier au Sénégal

    Directory of Open Access Journals (Sweden)

    Elhadji Faye

    2014-12-01

    Full Text Available Reactualisation of floristic and phytosociologic datas in Niayes and Peanut-Basin areas were undertook with village scale approach to better underline resources' conervation. In Savannah and sub-guinean areas specially in the Peanut-Basin and Niayes, 288 floristic samples were put in place in 6 villages in an stratified way based on ethnic groups, land use systems and topography. In the same time, 25 samples were realised in the 2 reference sites (Noflaye and Sambandé and comparison were made with researches conducted in 1940. Datas were submitted to multivariate analysis. SØrensen similarity index were used to compare villages systems and natural sites. Results showed discrimination of 11 phytosociologic groups: 5 of which came from natural sites (savanah G4 Hexalobus monopetalus et Gardenia ternifolia and G8 Acacia macrostachya et Ischaemum rugosum, secondary forest G10 Aphania senegalensis et Voaganca africana, semi-aquatic vegetations G1 Ipomoea aquatica et I. dichroa and G5 Phragmites australis subsp australis et Paspalum vaginatum and 6 from anthropic systems (disturbed areas G6 Echinochloa colona et Jussiae erecta and G7 Dactyloctenium aegyptium et Brachiaria disticophylla, and finally post-cultural zones with G2 Brachiaria disticophylla et Cenchrus biflorus, G3 Celosia trigyna et Digitaria velutina, G9 Tephrosia purpurea et Cenchrus biflorus and G11 Mitracarpus scaber et Eragrostis tremula. Natural sites groups were progressively invided by disturded area species and the others by ruderals and nitrophyl species. Overall floristic richness is about 336 species among which 260 from the Niayes sites and 176 from Peanut-Basin ones. References sites are always richer in terms af genera but peul areas are richer in termes of species. Differences were evidenced between actual taxa and Trochain (1940 descriptions. This methodological approach might be extended to other ecogeographical zones in Senegal in order to better identify and follow

  6. Germination traits of three weed species in Kosovo

    Directory of Open Access Journals (Sweden)

    A. Mehmeti

    2010-02-01

    Full Text Available Amaranthus retroflexus, Echinochloa crus-galli and Datura stramonium are the most important weed species in Kosovo. They cause severe yield depression, contaminate fodder and negatively affect growth and reproduction of other weed species. To counteract these problems, specific strategies need to be developed. Such strategies should consider information on species germination traits. In this context, our study provides information on temperature requirements for germination. Seeds of A. retroflexus, E. crus-galli and D. stramonium were harvested in two sub-regions of Kosovo (western and eastern parts differing in climate and land use. They were set for germination experiments in growth chambers at temperatures ranging from 3 to 35 °C and under field conditions. In both experiments, the germination rate differed between species and provenances. In the growth chamber experiment, germination of all three species was negligible below 15 °C and reached the highest rates between 24 and 30 °C. Seeds originating from the western part of Kosovo had higher germination rates and required a lower temperature for germination than seeds originating from the eastern part. In the field experiment, the time-dependent germination behaviour of D. stramonium differed between provenances. In general, germination started when soil temperature was above 18 °C and continued as long as the soil was moist. The results are discussed in the context of the need to develop weed management strategies against these weeds in Kosovo.

  7. Discriminating crop, weeds and soil surface with a terrestrial LIDAR sensor.

    Science.gov (United States)

    Andújar, Dionisio; Rueda-Ayala, Victor; Moreno, Hugo; Rosell-Polo, Joan Ramón; Escolá, Alexandre; Valero, Constantino; Gerhards, Roland; Fernández-Quintanilla, César; Dorado, José; Griepentrog, Hans-Werner

    2013-10-29

    In this study, the evaluation of the accuracy and performance of a light detection and ranging (LIDAR) sensor for vegetation using distance and reflection measurements aiming to detect and discriminate maize plants and weeds from soil surface was done. The study continues a previous work carried out in a maize field in Spain with a LIDAR sensor using exclusively one index, the height profile. The current system uses a combination of the two mentioned indexes. The experiment was carried out in a maize field at growth stage 12-14, at 16 different locations selected to represent the widest possible density of three weeds: Echinochloa crus-galli (L.) P.Beauv., Lamium purpureum L., Galium aparine L.and Veronica persica Poir.. A terrestrial LIDAR sensor was mounted on a tripod pointing to the inter-row area, with its horizontal axis and the field of view pointing vertically downwards to the ground, scanning a vertical plane with the potential presence of vegetation. Immediately after the LIDAR data acquisition (distances and reflection measurements), actual heights of plants were estimated using an appropriate methodology. For that purpose, digital images were taken of each sampled area. Data showed a high correlation between LIDAR measured height and actual plant heights (R2 = 0.75). Binary logistic regression between weed presence/absence and the sensor readings (LIDAR height and reflection values) was used to validate the accuracy of the sensor. This permitted the discrimination of vegetation from the ground with an accuracy of up to 95%. In addition, a Canonical Discrimination Analysis (CDA) was able to discriminate mostly between soil and vegetation and, to a far lesser extent, between crop and weeds. The studied methodology arises as a good system for weed detection, which in combination with other principles, such as vision-based technologies, could improve the efficiency and accuracy of herbicide spraying.

  8. Interactions between the flooding regime and floodplain grasslands in the Tana River Delta, in Kenya

    Science.gov (United States)

    Leauthaud, Crystele; Musila, Winfred; Duvail, Stéphanie; Kergoat, Laurent; Hiernaux, Pierre; Grippa, Manuela; Albergel, Jean

    2017-04-01

    The floodplain grasslands of the Tana River Delta, located on the East African coast in Kenya, form part of an intertwined socio-ecological deltaic system of high biodiversity value that delivers numerous goods and services. Mainly composed of Echinochloa stagnina (Retz) P. Beauv., a high-value forage species, this ecosystem is the major dry-season grazing grounds of the local pastoralist communities. The construction of hydroelectric infrastructure has led to a modification of the flooding regime. The impacts of the resulting reduction of floods in the deltaic zone on ecosystem properties and services still need to be assessed. In such a perspective, this study characterizes the link between the flooding regime of the Tana River and the growth pattern of its floodplain grassland. Aboveground dry phytomass was sampled for 15 months under a wide variety of naturally flooded and non-flooded conditions and controlled irrigation and cutting frequency treatments. Annual aboveground dry phytomass attained high values between 11 T.ha-1 and 32 T.ha-1 and annual net primary production of the grasslands reached 35 T.ha-1.year-1. Growth rates clearly depended on the flooding regime, management and climate conditions and were on average more than twice as fast during, and 50% faster after the floods, relative to pre-flood conditions. A plant growth model allowed testing the effect of different flooding regimes on plant productivity, confirming very low productivity in the absence of floods. These results suggest that rangeland and water management for the Tana River deltaic wetlands are tightly linked. The projected construction of another dam could lead to a reduction of flood extent and period and a decrease of grassland productivity and growth duration. Mitigation of this type of negative impacts, which will have direct and adverse consequences for the pastoralist communities as well as on the delivery of other goods and services, needs to be undertaken.

  9. [Mercury dynamics of several plants collected from the water-level fluctuation zone of the Three Gorges Reservoir area during flooding and its impact on water body].

    Science.gov (United States)

    Zhang, Xiang; Zhang, Cheng; Sun, Rong-guo; Wang, Ding-yong

    2014-12-01

    Submerged plants are a major source for the abnormal elevation of methylmercury in reservoir. Several specific plants (Echinochloa crusgalli, Cynodondactylon and Corn stover) were collected and inundated in a simulated aquatic environment in the laboratory for investigating the mercury (Hg) dynamics in plants and the release process into water, aiming to find out the properties of Hg dynamics of plants under inundation conditions and its impact on water body in the Water-Level Fluctuation Zone of the Three Gorges Reservoir Area. The results showed that the contents of total mercury in several plants were in the range of 9. 21-12.07 ng x g(-1), and the percentage content of methylmercury (MeHg) was about 1%-2%. The content of total mercury (THg) in plants gradually decreased, by 35.81%-55.96%, whereas that of the dissolved mercury (DHg) increased sharply, by 103.23% -232.15%, which indicated an emission of Hg from plants to water in the process of decomposition. Furthermore, the state of inundation provided sufficient conditions for the methylation process in plants and therefore caused an increase of the content of methylmercury in the plant residues, which was 3.04-6.63 times as much as the initial content. The concentration of dissolved methylmercury (DMeHg) in the overlying water also increased significantly by 14.84- 16.05 times compared with the initial concentration. Meanwhile, the concentration of dissolved oxygen (DO) in the overlying water was significantly and negatively correlated with DMeHg. On the other hand, the concentration of dissolved organic carbon (DOC) in the overlying water was significantly and positively correlated with DMeHg. During the whole inundation period, the increase of DHg in the overlying water accounted for 41.74% -47.01% of the total amount of THg emission, and there was a negative correlation between the content of THg in plant residues and that of DHg in the overlying water.

  10. Control de malezas en arroz de temporalcon clomazone, solo y en mezcla con propanily 2,4-d

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    Valent\\u00EDn A. Esqueda

    2000-01-01

    Full Text Available Control de malezas en arroz de temporal con clomazone, solo y en mezcla con propanil y 2,4-D. Se establecieron tres experimentos con el objetivo de evaluar el efecto del herbicida clomazone sólo y en mezcla con propanil y 2,4-D en el control de malezas y la toxicidad al arroz cv. Milagro Filipino desarrollado en condiciones de temporal. Los tres experimentos se establecieron en la zona arrocera de Los Naranjos, localizada en el Mpio. de Tres Valles en el estado de Veracruz. Las especies dominantes de malezas fueron: Cyperus iria, Echinochloa colona, Cyperus rotundus, Scleria setuloso- ciliata y Malachra fasciata. El clomazone aplicado en preemergencia, controló eficientemente E. colona en dosis de 0,72 y 0,96 kg i.a./ha, pero tuvo un efecto temporal y limitado sobre S. setuloso-ciliata y no tuvo efecto sobre C. iria y C. rotundus. La mezcla de clomazone + propanil + 2,4-D controló E. colona y C. iria a partir de la dosis de 0,60 + 1,44 + 0,24 kg i.a./ha. Asimismo, tuvo un buen control inicial de C. rotundus, pero su efecto sobre esta especie se perdió entre los 45 y 60 días después de la aplicación y su efecto sobre S. setuloso-ciliata estuvo influenciado por las condiciones de humedad en el terreno, a mayor humedad se tuvo mejor control de esta maleza y viceversa. En todos los casos, los rendimientos de arroz palay obtenidos con los tratamientos en donde se aplicó el clomazone sólo o en mezcla con propanil y 2,4-D, fueron estadísticamente semejantes a los obtenidos en los testigos regionales

  11. Can arbuscular mycorrhizal fungi reduce the growth of agricultural weeds?

    Science.gov (United States)

    Veiga, Rita S L; Jansa, Jan; Frossard, Emmanuel; van der Heijden, Marcel G A

    2011-01-01

    Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between -22 and -35%). In a subsequent experiment, we selected three of the negatively responding weed species--Echinochloa crus-galli, Setaria viridis and Solanum nigrum--and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions.

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

    Science.gov (United States)

    Yang, X-F; Kong, C-H

    2017-07-01

    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. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  13. Diet and body mass of wintering ducks in adjacent brackish and freshwater habitats

    Science.gov (United States)

    Miller, M.R.; Burns, E.G.; Wickland, B.E.; Eadie, J.M.

    2009-01-01

    Field-collected and hunter-donated ducks obtained during September-January of 1997-98 and 1998-99 were used to determine if food habits and body mass of Northern Pintails (Anas acuta) and Mallards (A. platyrhynchos) wintering in Suisun Marsh (Suisun), California, a managed estuarine brackish marsh, differed from values in the adjacent Sacramento-San Joaquin River Delta (the Delta), a freshwater region of grain fields flooded after harvest. Ducks in Suisun fed primarily on seeds of Sea Purslane (Sesuvium verrucosum), followed by Alkali Bulrush (Schoenoplectus maritimus) and Wild Millet (Echinochloa crusgalli), together forming 73-90% (aggregate % dry mass) of the diets. Ducks in the Delta fed primarily on seeds of Smartweed (Polygonum spp.), followed by corn (Zea mays) and tomato seeds (Lycopersicon esculentum), together forming 62-88% of the diets. Pintails and Mallards collected in Suisun each had similar (5 of 11 seasonal comparisons) or greater (6 of the 11 comparisons) body mass compared to their conspecifics collected from the Delta (90% confidence interval analyses), despite a composite diet in the Delta having about 39% greater metabolizable energy content (ME) and 24% greater protein content than in Suisun. Therefore, diet quality alone was not a predictor of body mass in these two areas. Other factors must have been involved, such as greater food abundance and density, lower waterfowl abundance and density, or lower daily energy costs in Suisun. Direct measurement of these factors should explain the apparent inconsistencies in body mass relative to food quality in these brackish and freshwater habitats.

  14. Periodo de interferencia de arvenses en el cultivo de berenjena (Solanum melongena L.

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    Aramendiz-Tatis Hermes

    2010-04-01

    Full Text Available

    Dada la importancia de la berenjena en la horticultura del Caribe colombiano, el presente trabajo buscó establecer las bases de un manejo sustentable e integrado de malezas en este cultivo, basado en el período de máxima interferencia de aquellas sobre este. El estudio se realizó en la Universidad de Córdoba, ubicada en Montería (8°39’ N; 75°58’ W. El diseño experimental consistió en bloques completamente aleatorizados, con cuatro repeticiones y siete tratamientos relacionados con periodos crecientes de control de arvenses, seguidos por ausencia de control. Los resultados muestran que las arvenses con mayor presencia fueron paja mona (Leptochloa filiformis [Lam.] Beauv., caminadora (Rottboellia cochinchinensis [Lour.] W.D. Clayton, liendre de puerco (Echinochloa colona [L.] Link., coquito (Cyperus rotundus L. y bledo (Amaranthus retroflexus L.. Las arvenses afectaron la altura de la planta, el diámetro del tallo, y el rendimiento y calidad del fruto. Este último parámetro no se ve afectado cuando el cultivar lila se mantiene limpio durante los primeros 40 días. Al considerar el tipo de productor de esta hortaliza en el valle del Sinú, se sugiere utilizar: i para áreas pequeñas, métodos físicos, como el arranque manual o corte con machete u otra herramienta, y prácticas culturales; ii para áreas grandes, la combinación de herbicidas de presiembra con métodos físicos y culturales.

  15. Climate change impact research on arable weeds – data, methods and applications at various scale levels

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    Breitsameter, Laura

    2014-02-01

    Full Text Available In the past years, a large number of studies have examined various aspects of possible consequences of climate change for the biology and damage potential of arable weeds. However, there are merely a few examples that have comprehensively investigated individual weed species or arable crop systems within a clearly delimited geographical area. In the frame of the research co-operation KLIFF (Climate change impact and adaptation research for Lower Saxony, we tested an approach that combines a number of methods to span several scale levels and types of environmental factors, which was intended to provide as accurate as possible an estimate of the potential distribution and performance of individual arable weed species under the predicted future climate conditions. This approach was put to practice for the species Abutilon theophrasti, Amaranthus retroflexus, Echinochloa crus-galli, Datura stramonium, Iva xanthiifolia and Setaria viridis. We combined projections of the potential future distribution of the individual weed species based on a correlative distribution modelling approach (regional scale level with pot experiments (local scale level on the vegetative and generative performance of these species under climatic conditions predicted for the end of the current century for Lower Saxony. A synopsis revealed that the results obtained from the different approaches corresponded to a large extent. For A. retroflexus, D. stramonium, E. crus-galli, and S. viridis, both approaches indicated a neutral or positive effect of the predicted future climate on their potential distribution and performance, whereas the opposite was found for I. xanthiifolia. Merely for A. theophrasti, results of the two methods did not fully concur. Altogether, our results highlight that investigating climate change impact on weeds by combining several methods to span several scale levels allows fitting various data sets to a comprehensive picture for a delimited region. It has

  16. Application of ridge regression to quantify marginal effects of collinear soil properties on phytoaccumulation of arsenic, cadmium, lead, and zinc.

    Science.gov (United States)

    Anderson, Richard H; Basta, Nicholas T

    2009-03-01

    Soil properties that mitigate hazardous effects of environmental contaminants through soil chemical sequestration should be considered when evaluating ecological risk from terrestrial contamination. The objective of this research was to identify predominant soil chemical/physical properties that modify phytoaccumulation of As, Cd, Pb, and Zn to the non-hyperaccumulating higher plants: Alfalfa (Medicago sativa L.), perennial ryegrass (Lolium perenne L.), and Japanese millet (Echinochloa crusgalli L.). Transmission coefficients were estimated from a dose-response experiment with the use of aboveground tissue contaminant concentrations and correlated with selected soil property measurements to develop statistical prediction models for soil-specific adjustments to ecological risk assessments. Significant correlations between soil properties and transmission coefficients were observed for all four contaminants. Intercorrelation was also observed among soil properties, including cation exchange capacity (CEC) and soil pH (p = 0.035), CEC and total clay (p = 0.030), organic carbon (OC) and total clay content (p = 0.085), reactive iron oxides (FeOX) and OC (p = 0.078), and reactive Mn oxide (MnOX) and total clay content (p Ridge regression, a technique that suppresses the effects of multicollinearity and enables prediction, was used to assess the marginal contributions of soil properties found to mitigate phytoaccumulation. Prediction models were developed for all four contaminants. Significant variables were FeOX for As or pH, OC, CEC, clay content, or a combination of factors for cationic metal models. Ridge regression provides a powerful alternative to conventional multiple regression techniques for ecotoxicological studies when intercorrelated predictors are experimentally unavoidable, as with soil properties.

  17. Evaluation of multi-species weed competition and weeds population dynamic in corn Zea mays L. field

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    S Mijani

    2016-05-01

    Full Text Available In order to examine the multi-species weed competition in corn field an experiment as an interval mapping was carried out at the Agricultural Research field of Ferdowsi University of Mashhad during growing season 2009-2010. At 3-4 leafy stages of corn, 20 non-destructive quadrates determine and the density of weeds was counted separately. At the same time, 20 destructive quadrates determine and in addition of counting number of plants, leaf area index and dry weight of each species were recorded separately. By using data from previous section, hyperbolic functions were fitted. In these functions number of species serve as the independent variable, weight or leaf area was considered as the dependent variable. With the help of these functions and leaf dry weight of each species was determined for non-destructive quadrates at this stage. Relative leaf area at early season as independent variables and natural logarithm of individual plant weight at later season as dependent variable in a multiple linear regression was fitted to obtain the interspecies competition coefficients. Based on ln of weight of single plant equation the weed interference effects on the corn yield can be divided into two groups: inhibition (negative sign and stimulation (positive sign. Among all weeds, night shade (Solanum nigrum L., redroot pigweed (Amaranthus retroflexus L. and lambsquarter (Chenopodium album L. had positive effects on corn yield, respectively. In fact, these weeds had competition and negative impacts on other weeds and reduced their competition power with corn and caused facilitation role on corn yield. At the end of growing season of corn, population of lambsquarter and Common purslane (Portulaca oleracea L. decreased while population of barnyard grass(Echinochloa crus-galli L., redroot pigweed and night shade increased.

  18. Effect of the foliar enrichment and herbicides on maize and associated weeds irrigated with drainage water

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    Roshdy M.H. Tagour

    2017-12-01

    Full Text Available A two-year field experiment was conducted during summer seasons of 2013 and 2014, which were irrigated by drainage water which belong to salinity class (C3S1 to C4S2, to study the effect of the foliar enrichment namely (Anti-stress and weed management treatments (some pre and post-emergence herbicides and two-hand hoeing on maize growth, yield, yield components and chemical composition of maize grains and associated weeds (Portulaca oleracea, Amaranthus retroflexus and Echinochloa colonum. The results illustrated that application of the foliar enrichment enhanced the dry weight of weeds and increased maize growth characters, yield and yield components and total crude protein and total oil percentage of grain maize, as compared with untreated treatment. All weed management treatments caused a significant reduction in total dry weight of weeds at 60 and 80 days after sowing in both seasons. Two-hand hoeing treatment exerted the highest decrease in total dry weight of weeds followed by metribuzin, oxadiagyl, fluroxypyr and bentazon, respectively at 60 and 80 days after sowing compared with other weed management treatments. While, the highest values of maize growth, yield, yield components and maize grains' content of protein and oil was obtained with two-hand hoeing followed by metribuzin, oxadiagyl, fluroxypyr and bentazon, respectively. While, two hands hoeing produced the maximum values of leaf area, ear length, the weight of kernels plant−1, but applying of metribuzin treatment gave the highest values of total oil percentage of grain maize when the foliar enrichment was used.

  19. Características micromorfológicas de biótipos de capim‑arroz resistente e suscetível ao quinclorac

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    Evander Alves Ferreira

    2012-08-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito do quinclorac nas características anatômicas de folhas e raízes de biótipos de capim‑arroz (Echinochloa spp., resistente e suscetível a este herbicida, por meio de avaliações micromorfométricas. As plantas foram cultivadas em vasos de plástico com capacidade de 250 cm³. As imagens dos cortes foram obtidas com microscópio de luz equipado com sistema U‑Photo, acoplado à câmera digital conectada a microcomputador. Na seção transversal da lâmina foliar e das raízes, utilizou-se objetiva de 10X, tendo-se avaliado 20 cortes/campos por planta, com dez medições por corte e quatro repetições por tratamento. Observaram-se diferenças entre os biótipos resistente e suscetível, tanto na ausência quanto na presença do quinclorac. O biótipo resistente apresenta lâmina foliar pouco afetada pelo herbicida; no entanto, há modificação na constituição dos tecidos radiculares com a formação mais acentuada de aerênquima. O biótipo suscetível também apresenta formação de aerênquima quando tratado com o quinclorac, mas em quantidade inferior à observada no biótipo resistente.

  20. MANEJO DA ÁGUA E UTILIZAÇÃO DE OXYFLUORFEN NO CONTROLE DE PLANTAS DANINHAS NA CULTURA DO ARROZ IRRIGADO NO SISTEMA PRÉ-GERMINADO

    Directory of Open Access Journals (Sweden)

    FURLANI JUNIOR ENES

    1997-01-01

    Full Text Available Realizou-se uma pesquisa no ano agrícola 1993/94, na Estação Experimental de Pindamonhangaba (SP, e cujos objetivos foram verificar a necessidade da troca da água no sistema de cultivo pré-germinado para arroz (Oryza sativa L. irrigado por inundação e o efeito de doses do herbicida Oxyfluorfen (240 g de ingrediente ativo por litro do produto comercial e momento de inundação da área, sobre o comportamento da cultura do arroz e reflexos sobre a comunidade de plantas daninhas presentes nas áreas experimentais. Utilizaram-se os tratamentos TI10 - testemunha inundada 10 dias após o preparo do solo, e TIPS - testemunha com solo inundado logo após o preparo do solo, comparadas com duas doses de Oxyfluorfen (1 e 2 L/ha do produto comercial e ao manejo com e sem troca da água tratada com herbicida. O uso da inundação logo após o preparo do solo e do herbicida ocasiona os melhores níveis de controle das plantas daninhas. A inundação logo após o preparo do solo propicia os melhores níveis de controle das plantas daninhas, quando comparado à inundação realizada 10 dias após. O Oxyfluorfen mostrou-se eficiente no controle das plantas daninhas, principalmente o capim-arroz (Echinochloa sp., no sistema com sementes pré-germinadas em arroz irrigado por inundação. Respeitando-se o período de carência para posterior semeadura e não ocorrendo baixa luminosidade durante esse tempo, não há necessidade de efetuar a troca da água onde foi aplicado o herbicida Oxyfluorfen.

  1. The consequent influence of crop rotation and six-year-long spring barley monoculture on yields and weed infestation of white mustard and oats

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    Cezary Kwiatkowski

    2012-12-01

    Full Text Available The present study was conducted in the years 2007- 2008, after 6-year-long experiments in the cultivation of spring barley in a crop rotation system and in monoculture. The other experimental factor was the spring barley protection method. Intensive protection involved comprehensive treatment of barley (in-crop harrowing, seed dressing, application of herbicides, fungicides, a retardant and an insecticide. Extensive protection consisted only in in-crop harrowing, without the application of crop protection agents, except for seed dressing. The above mentioned factors formed the background for the study on the cultivation of white mustard and oats, as phytosanitary species, in successive years. In the test plants, no mineral fertilization and crop protection were applied. Such agricultural method enabled an objective assessment of the consequent effect of monoculture, crop rotation and crop treatments. A hypothesis was made that the cultivation of the phytosanitary plants in the stand after 6-year-long barley monoculture would allow obtaining the level of yields and weed infestation similar to those of the crop rotation treatments. It was also assumed that the cultivation of white mustard and oats would eliminate differences in plant productivity caused by the negative influence of extensive protection. It was proved that the cultivation of the phytosanitary plants eliminated the negative influence of monoculture on the level of their yields and weed infestation. However, the test plants did not compensate negative consequences of extensive protection. In spite of this, white mustard and oats effectively competed with weeds, and the number and weight of weeds in a crop canopy did not cause a dramatic decline in yields. In the test plant canopy, the following short-lived weeds were predominant: Chenopodium album, Galinsoga parviflora, Echinochloa crus-galli. The absence of herbicide application resulted in the compensation of perennial species

  2. Respostas de cultivares de soja transgênica e controle de plantas daninhas em função de épocas de aplicação e formulações de glyphosate Performance of transgenic soybean cultivars and weed control in function of application times and glyphosate formulations

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    D. Agostinetto

    2009-01-01

    season and arranged in a randomized complete block design in split-split plots, with four replications. Roundup Ready (RR soybean cultivars were allocated in the plots (BRS 244RR, MSOY 7979RR and NR, not registered ones; application times (20, 35 and 50 days after emergence were allocated in the split-plots; and the glyphosate formulations (isopropylamine salt - Roundup Ready® or Roundup Transorb®, ammonium salt - Roundup WG® and potassium salt-Zapp Qi® at the rate of 720 g a.e. ha-1 and infested ckeck were allocated in the split-split plots. The yield parameters evaluated were culture herbicide phytotoxicity, weed control, number of green beans and grains per plant, grain weight and grain yield. The herbicide glyphosate in the tested formulations was selective to the tested soybean cultivars. In general, the best weed control formulation was Roundup WG®. At the initial development of the culture, herbicide application provided better control of purslane, redroot pigweed, alexandergrass, barnyardgrass and bermudagrass. Grain yield varied among soybean cultivars but it did not differ among the glyphosate formulations, being higher when the application was accomplished at the late stages of culture development.

  3. The influence of the Amazonian floodplain ecosystems on the trace element dynamics of the Amazon River mainstem (Brazil).

    Science.gov (United States)

    Viers, Jérôme; Barroux, Guénaël; Pinelli, Marcello; Seyler, Patrick; Oliva, Priscia; Dupré, Bernard; Boaventura, Geraldo Resende

    2005-03-01

    The purpose of this paper is to forecast the role of riverine wetlands in the transfer of trace elements. One of the largest riverine wetlands in the world is the floodplain (várzea) of the Amazon River and its tributaries (Junk and Piedade, 1997). The central Amazon wetlands are constituted by a complex network of lakes and floodplains, named várzeas, that extend over more than 300,000 km2 (Junk, W.J., The Amazon floodplain--a sink or source for organic carbon? In Transport of Carbon and Minerals in Major World Rivers, edited by E.T. Degens, S. Kempe, R. Herrera, SCOPE/UNEP; 267-283, 1985.) and are among the most productive ecosystems in the world due to the regular enrichment in nutrients by river waters In order to understand if the adjacent floodplain of Amazon River have a significant influence on the trace element concentrations and fluxes of the mainstem, the concentrations of selected elements (i.e., Al, Mn, Fe, Co, Cu, Mo, Rb, Sr, Ba, and U) have been measured in the Amazon River water (Manacapuru Station, Amazonas State, Brazil) and in lake waters and plants (leaves) from a várzea(Ilha de Marchantaria, Amazonas State, Brazil) during different periods of the hydrological cycle. Four plant species (two perennial species: Pseudobombax munguba and Salix humboldtiana, and two annual herbaceous plants: Echinochloa polystachya and Eichhornia crassipes) were selected to represent the ecological functioning of the site. Time series obtained for dissolved Mn and Cu (River water could not be explained by tributary mixing or instream processes only. Therefore, the contribution of the waters transiting the floodplains should be considered. These results suggest that the chemical composition of the waters draining these floodplains is controlled by reactions occurring at sediment-water and plant-water interfaces. Trace elements concentrations in the plants (leaves) vary strongly with hydrological seasonality. Based on the concentration data and the biological

  4. The effect of soil mulching with organic mulches, on weed infestation in broccoli and tomato cultivated under polypropylene fibre, and without a cover

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    Kosterna Edyta

    2014-07-01

    Full Text Available An investigation was done on the effect of different types of organic mulches that were applied in form of straw to the soil mulching process, on the weed infestation, number, and fresh mass of weeds in broccoli cv. Milady F1 (Brassica oleracea L. var. italica Plenck and tomato cv. Polfast F1 (Lycopersicon esculentum Mill. grown under polypropylene fibre as a covering, or grown without a covering. The different types of organic straw mulches were: rye (Secale cereale L., corn (Zea mays L., rape (Brassica napus L. subsp. napus, and buckwheat (Fagopyrum esculentum Moench.. All the organic mulches were applied at a dose of 10 t/ha. The effect of the mulches was compared to a control plot which had no mulch. The type of organic mulch applied to the soil mulching process influenced species composition, number, and fresh mass of weeds. This effect could be the result of the properties of the mulch (colour, structure, etc. or the allelopathic effect on the germination and growth of individual weeds species. Irrespective of the investigated factors, 24 and 25 weeds species, respectively, were observed immediately after cover removal and before broccoli and tomato harvest. In the first date of estimation Chenopodium album L., Echinochloa crus-galli (L. P. Beauv., Fallopia convolvulus (L. Á. Löve, Stellaria media (L. Vill., and Viola tricolor L. dominated, however, before the vegetables were harvested Ch. album, V. tricolor, Veronica arvensis L., and E. crus-galli dominated. An application of polypropylene fibre contributed to an increase in the number and fresh mass of weeds in both vegetables in the first date of estimation (after cover removal. During this period, vegetables cannot compete with weeds. It is important to note, though, that before the vegetables were harvested, a decrease was found in the number and fresh mass of weeds in the covered plots. The most efficient weed limiter, both after cover removal and also before the broccoli and

  5. Towards Biological Restoration of Tehran Megalopolis River Valleys- Case Study: Farahzad River

    Science.gov (United States)

    Samadi, Nafishe; Oveis Torabi, Seyed; Akhani, Hossein

    2017-04-01

    surrounding steep slopes. The rare local endemic Convolvulus gracillimus still occurs in surrounding dry slopes. Ailanthus altissima is an invasive introduced tree largely occupied disturbed habitats and slopes of the valley associated with large number of ruderals belonging to genera Amaranthus, Bassia, Chenopodium, Echinochloa, Heliotropium, Tribulus etc. Restoration plan include 1. Study of past biological and geomorphological conditions of the area based on remnants of vegetation and aerial and satellite imaginary data 2. Survey of present environmental conditions of the area including identification native and introduced plants and animals, assessing the degree of originality of existing vegetation and cultural landscapes and abiotic factors. 3. Soil reclamation and topography improvements towards cultivation and/or formation of natural vegetation.

  6. Discrimination of corn from monocotyledonous weeds with ultraviolet (UV) induced fluorescence.

    Science.gov (United States)

    Panneton, Bernard; Guillaume, Serge; Samson, Guy; Roger, Jean-Michel

    2011-01-01

    In production agriculture, savings in herbicides can be achieved if weeds can be discriminated from crop, allowing the targeting of weed control to weed-infested areas only. Previous studies demonstrated the potential of ultraviolet (UV) induced fluorescence to discriminate corn from weeds and recently, robust models have been obtained for the discrimination between monocots (including corn) and dicots. Here, we developed a new approach to achieve robust discrimination of monocot weeds from corn. To this end, four corn hybrids (Elite 60T05, Monsanto DKC 26-78, Pioneer 39Y85 (RR), and Syngenta N2555 (Bt, LL)) and four monocot weeds (Digitaria ischaemum (Schreb.) I, Echinochloa crus-galli (L.) Beauv., Panicum capillare (L.), and Setaria glauca (L.) Beauv.) were grown either in a greenhouse or in a growth cabinet and UV (327 nm) induced fluorescence spectra (400 to 755 nm) were measured under controlled or uncontrolled ambient light intensity and temperature. This resulted in three contrasting data sets suitable for testing the robustness of discrimination models. In the blue-green region (400 to 550 nm), the shape of the spectra did not contain any useful information for discrimination. Therefore, the integral of the blue-green region (415 to 455 nm) was used as a normalizing factor for the red fluorescence intensity (670 to 755 nm). The shape of the normalized red fluorescence spectra did not contribute to the discrimination and in the end, only the integral of the normalized red fluorescence intensity was left as a single discriminant variable. Applying a threshold on this variable minimizing the classification error resulted in calibration errors ranging from 14.2% to 15.8%, but this threshold varied largely between data sets. Therefore, to achieve robustness, a model calibration scheme was developed based on the collection of a calibration data set from 75 corn plants. From this set, a new threshold can be estimated as the 85% quantile on the cumulative frequency

  7. Chemical composition and phytotoxicity of volatile essential oil from intact and fallen leaves of Eucalyptus citriodora.

    Science.gov (United States)

    Batish, Daizy R; Singh, Harminder P; Setia, Nidhi; Kaur, Shalinder; Kohli, Ravinder K

    2006-01-01

    A total of 23 volatile constituents was identified and characterized by GC and GC-MS in the volatile essential oil extracted from intact (juvenile and adult) and fallen (senescent and leaf litter) leaves of lemon-scented eucalyptus (Eucalyptus citriodora Hook.). The leaves differed in their pigment, water and protein content, and C/N ratio. The oils were, in general, monoterpenoid in nature with 18 monoterpenes and 5 sesquiterpenes. However, a great variability in the amount of essential oils and their individual constituents was observed in different leaf tissues. The amount was maximum in the senescent leaves collected from the floor of the tree closely followed by that from juvenile leaves. In all, 19 constituents were identified in oil from juvenile and senescent leaves compared to 23 in adult leaves and 20 in leaf litter, respectively. Citronellal, a characteristic monoterpene of the oil reported hitherto was found to be more (77-78%) in the juvenile and senescent leaves compared to 48 and 54%, respectively, in the adult leaves and leaf litter. In the adult leaves, however, the content of citronellol--another important monoterpene-- was very high (21.9%) compared to other leaf types (7.8-12.2%). Essential oil and its two major monoterpenes viz. citronellal and citronellol were tested for their phytotoxicity against two weeds (Amaranthus viridis and Echinochloa crus-galli) and two crops (Triticum aestivum and Oryza sativa) under laboratory conditions. A difference in the phytotoxicity, measured in terms of seedling length and dry weight, of oil from different leaves and major monoterpenes was observed. Oil from adult leaves was found to be most phytotoxic although it occurs in smaller amount (on unit weight basis). The different toxicity of different oil types was due to the relative amount of individual monoterpenes present in the oil, their solubility and interactive action. The study concludes that oil from senescent and juvenile leaves being rich in

  8. Eficácia de herbicidas no controle de plantas daninhas na cultura da cebola em semeadura direta Efficacy of herbicides on weed control in onion direct sowing

    Directory of Open Access Journals (Sweden)

    Lino R. Ferreira

    1999-04-01

    Full Text Available As plantas de cebola provenientes da semeadura direta no campo são mais danificadas pelo cultivo mecânico e são mais sensíveis aos herbicidas, principalmente os latifolicidas, do que quando transplantadas. Com o objetivo de avaliar a eficácia dos herbicidas oxyfluorfen, ioxynil-octanoato e fluazifop-p-butil, aplicados em pós-emergência, isoladamente ou em mistura no tanque, com ou sem aplicação de paraquat, antes da emergência das plantas de cebola, conduziu-se este trabalho no município de Monte Alto, SP. Nenhum dos herbicidas aplicados isoladamente foi eficiente no controle de todas as espécies daninhas presentes na área experimental. As misturas no tanque de fluazifop-p-butil com oxyfluorfen ou ioxynil-octanoato, independente da aplicação ou não de paraquat aos cinco dias após a semeadura, controlaram eficientemente Portulaca oleracea, Amaranthus lividus, Echinochloa crusgalli, Eragrostis pilosa, Digitaria horizontalis, Eleusine indica e Brachiaria plantaginea, com produção de bulbos semelhante à da testemunha capinada.Onion plants, from direct sowing to the field, are more damaged by mechanical cultivation and more sensitive to herbicides, especially to broadleaf herbicides, than transplanted onions. With the purpose of evaluating the efficacy of the herbicides oxyfluorfen, ioxynyl-octanoato and fluazifop-p-butyl, applied in post-emergence, alone or tank mix, with or without paraquat application, before onion plants emergence, this investigation was carried out at Monte Alto County, São Paulo State, Brazil. None of the herbicides sprayed alone were efficient in the control of all the weeds present in the experimental area. The tank mix of fluazifop-p-butyl plus oxyfluorfen or ioxynyl-octanoato, regardless of paraquat application, at five days after sowing, controlled efficiently Portulaca oleracea, Amaranthus lividus, Echinoclhoa crusgalli, Eragrostis pilosa, Digitaria horizontalis, Eleusine indica and Brachiaria

  9. Synthesis and herbicidal activity of isoindoline-1,3-dione substituted benzoxazinone derivatives containing a carboxylic ester group.

    Science.gov (United States)

    Huang, Ming-Zhi; Luo, Fei-Xian; Mo, Hong-Bo; Ren, Ye-Guo; Wang, Xiao-Guang; Ou, Xiao-Ming; Lei, Man-Xiang; Liu, Ai-Ping; Huang, Lu; Xu, Man-Cai

    2009-10-28

    A carboxylic ester group was introduced to three series of isoindolinedione substituted benzoxazinone derivatives. Some of these analogues exhibited good herbicidal activities, and the injury symptoms against weeds included leaf cupping, crinkling, bronzing, and necrosis, typical of protox inhibitor herbicides. Structurally, they were classified as Chemical Group A (4-carboxylic ester group-6-isoindolinyl-benzoxazinones), B (4-carboxylic ester group-7-isoindolinyl-benzoxazinones), and C (4-carboxylic ester group-6- tetrahydroisoindolinyl-benzoxazinones). All of the tested compounds were structurally confirmed by (1)H NMR, IR, mass spectroscopy, and elemental analysis. Preliminary bioassay data of these three classes of compounds showed that, in general, the order of the herbicidal effectiveness is C > A > B. Several of the lead compounds, for example, C10 (methyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2-methyl-3-oxo-2H-benzo[b][1,4] oxazin-4(3H)-yl) propano-ate), C12 (ethyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2- methyl-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl) propanoate), and C13 (ethyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2-methyl-3-oxo-2H-benzo-[b][1,4]oxazin-4(3H)-yl) butanoate), exhibited greater than 80% control at 75 g a.i./ha in both pre- and postemergence treatments against dicotyledonous weeds, such as Abutilon theophrasti Medic, Chenopodium album L., and Amaranthus ascendens L., and monocotyledon weeds, such as Digitaria sanguinalis L., Echinochloa crus-galli L., and Setaria viridis L. On the basis of advanced screening tests and crop selectivity, compounds C10, C12, and C13 are safer to crops than flumioxazin. Compounds C10, C12, and C13 are potent to develop as pre-emergent herbicides used in peanut, soybean, maize, and cotton fields.

  10. Intoxicações por plantas diagnosticadas em ruminantes e equinos e estimativa das perdas econômicas na Paraíba Plant poisonings diagnosed in ruminants and horses and estimation of the economical losses in Paraíba

    Directory of Open Access Journals (Sweden)

    Tales S. Assis

    2010-01-01

    Full Text Available Foi realizado um levantamento dos surtos de intoxicações por plantas em ruminantes e equinos diagnosticados no Laboratório de Patologia Veterinária (LPV, do Hospital Veterinário da Universidade Federal de Campina Grande, Campus de Patos, Paraíba, no período de 2000-2007. Em bovinos 7,4% dos diagnósticos realizados pelo LPV foram intoxicações por plantas. Foram diagnosticadas intoxicações por Centhraterum brachylepis (um surto, Brachiaria spp. (um surto, Crotalaria retusa (dois surtos, Ipomoea batatas (um surto, Marsdenia sp. (um surto, gramíneas contendo nitratos e nitritos (um surto por Echinochloa polystachya e dois surtos por Pennisetum purpureum, Palicourea aeneofusca (um surto, Prosopis juliflora (três surtos, Nerium oleander (um surto e Mimosa tenuiflora (sete surtos. Na espécie ovina 13% dos diagnósticos foram intoxicações por plantas. Os surtos foram causados por Ipomoea asarifolia (quatro surtos, Brachiaria spp. (três surtos, Crotalaria retusa (dois surtos, Tephrosia cinerea (dois surtos, Panicum dichotomiflorum (um surto, Mascagnia rigida (um surto e malformações associadas à ingestão de Mimosa tenuiflora (20 surtos. Nos caprinos, 6,4% dos diagnósticos corresponderam à intoxicação por plantas. Sete surtos foram causados por Mimosa tenuiflora, um por Ipomoea asarifolia, um por Ipomoea carnea, um por Ipomoea riedelli, três por Prosopis juliflora, um por Arrabidaea corallina, dois por Aspidosperma pyrifolium, dois por Turbina cordata e um por Opuntia ficus-indica. Na espécie equina 14% das doenças diagnosticadas foram devidas a intoxicações por plantas, sendo 12 surtos por Crotalaria retusa e um por Turbina cordata. As perdas na Paraíba por plantas tóxicas são estimadas em 3.895 bovinos, 8.374 ovinos, 6.390 caprinos e 366 equinos, que representam uma perda econômica anual, por morte de animais, de R$ 2.733.097,00. São relatados alguns aspectos epidemiológicos, sinais clínicos e patologia de surtos de

  11. Evaluation of allelopathic potential and quantification of momilactone A,B from rice hull extracts and assessment of inhibitory bioactivity on paddy field weeds.

    Science.gov (United States)

    Chung, Ill Min; Kim, Jung Tae; Kim, Seung-Hyun

    2006-04-05

    Rice (Oryza sativa L.) hull extracts were used in a bioassay to evaluate the allelopathic potential of rice on the germination and growth of barnyard grass (Echinochloa crus-galli P. Beauv. var. oryzicola Ohwi), to quantify momilactone A and B levels in rice hull germplasm and to assess the inhibitory bioactivity of momilactone A and B as a potential natural source of herbicide for weed control in paddy fields. Four varieties of weeds including E. crus-galli P. Beauv. var. oryzicola Ohwi, Monochoria vaginalis var. plantaginea, Scirpus juncoides, and Eleocharis kuroguwai were tested in the paddy field. Of 99 rice varieties, the top five including Noindari exhibited inhibition effects greater than 50% in average inhibition of dry weight (AIDW). Noindari among them exerted the strongest effect (55.6%). The next five in the ranking exhibited inhibition effects of greater than 40%. Also, 46 varieties had inhibition effects between 20 and 40%, and 29 varieties had inhibition effects greater than 10%. Fourteen varieties had very low inhibitory effects (less than 10%), the lowest of which was Heunbe (4.7%). These varieties showed a mean inhibition of 19.8% for germination rate (GR), 9.9% for germination percentage (GP), 16.6% for leaf dry weight (LDW), 38.9% for straw dry weight (SDW), and 26.8% for root dry weight (RDW). Rice varieties were classified into six categories based on their total momilactones (TMs) (momilactone A + momilactone B). The highest level of momilactone A was found in the Baekna rice variety (34.7 microg g(-1)), and Baekgwangok contained the highest level of momilactone B (37.8 microg g(-1)). In allelopathic potential with genetic properties and morphological characteristics, the total inhibition rate (TIR) was 18.3% for Korean rice varieties, 19.0% for middle maturing varieties, 17.8% for colorless hull varieties, 18.3% for awn varieties, and 19.0% for colorless awn varieties. In addition, Korean varieties showed higher TMs (4.5 microg g(-1)) as