Publications

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a physoderma disease of barnyard grass. 195313113222
enzyme detoxication of 3',4'-dichloropropionanilide in rice and barnyard grass, a factor in herbicide selectivity. 19676074948
diphenamid metabolism in plants.diphenamid, a herbicide, is metabolized to n-methyl 2,2-diphenylacetamide and 2,2-diphenylacetamide by the common soil fungi trichoderma viride and aspergillus candidus within 48 hours. the two metabolites are more toxic than diphenamid to both tomato and barnyard-grass seedlings under sterile conditions. this finding indicates that the phytotoxic moiety is not diphenamid but one of its metabolites-probably the n-methyl derivative.196717738227
mechanism for the differential translocation of amiben in plants.the proportion of the total plant radioactivity present in shoots at the end of a 24-hour exposure of the roots to 0.5 milligram per liter (14)c-3-amino-2,5-dichlorobenzoic acid ((14)c-amiben) ranged from 1.4 to 74.3% in 13 species. when roots of 10-day-old wheat (triticum aestivum l. em. thell., triumph) and 13-day-old barnyard grass (echinochloa crusgalli l. beauv.) plants were treated with 0.5 milligram per liter (14)c-amiben for 12 or 24 hours, barnyard grass shoots contained at least eight ...197016657538
heterodera graminophila n. sp. (nematoda heteroderae) from grass with a key to closely related species.heterodera graminophila n. sp., a member of the h. goettingiana group, is described and illustrated from roots of barnyard grass, echinochloa colonum (l.) link, in baton rouge, la. this new abullate species, having second-stage larvae with only three lines in the lateral field, is most closely related to h. cyperi golden, rau &cobb, 1962, and h. graminis stynes, 1971, but differs particularly in having a small, inconspicuous anus without a circum-anal pattern and located about 20% of the cyst le ...197219319258
the effect of atmospheric humidity on photosynthesis, transpiration and water use efficiency of leaves of several plant species.the effect of humidity on the gas exchange of leaves of the dicotyledons soybean (glycine max (l.) merrill), sunflower (helianthus annuus l.), jojoba (simmondsia chinensis (l.) schneider), and saltbush (atriplex halimus l.) and the monocotyledons wheat (triticum aestivum l.), barley (hordeum vulgare l.) sorghum (sorghum bicolor (l.) moench) and barnyard grass (echinochloa crus-galli (l.) beauv.) was examined under conditions of adequate soil moisture in a controlled environment. photosynthesis a ...197724419571
[phytotoxicity of di,sec.butylamides of halogenoalkoxybenzoic acids].n,n-di,sec.butylamides of halogenated alkoxybenzoic acids were prepared and tested for phytotoxic activity. the corresponding acids and a series of n-alkyl- and n,n-dialkylamides of 2-methoxy-3,5-dichlorobenzoic acid were studied in parallel. the phytotoxicity of these substances was tested against seven representative weeds and some crop plants using both pre- and post-emergence test at doses of 6 kg/ha or lower. the amides studied proved more strongly phytotoxic on absorption through the root ...1978738441
a mechanism of chlorosis caused by 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-5-hydroxypyrazole, a herbicidal compound.in organic solvents, 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-5-hydroxypyrazole (dtp) converted chlorophyll a and b extracted from rice seedlings (oryza sativa l. ;kinmaze') into pheophytin a and b, respectively. on comparing the chlorophyll-converting activity of dtp to those of acetic, glycolic, 2,4-dichlorobenzoic, monochloroacetic, 2,6-dichlorobenzoic, pyruvic, and dichloroacetic acids, it was demonstrated that dtp induced h(+) into chlorophyll specifically. 5-hydroxypyrazoles, which seem to be ...197916661052
production of 9-beta-d-arabinofuranosyladenine by a new species of streptomyces and its herbicidal activity.9-beta-d-arabinofuranosyladenine (ara-a) was produced by a new species of streptomyces designated as s. herbaceus. ara-a was found to have potent herbicidal activity against echinochloa crus-galli, digitaria adscendens and chenopodium ficifolium by the treatment with ara-a before germination of these plants. however, oryza sativa had strong resistance to ara-a.1979528365
anaerobic metabolism in germinating seeds of echinochloa crus-galli (barnyard grass) : metabolite and enzyme studies.echinochloa crus-galli, a problem weed in rice fields, has the rare ability to germinate and to grow in a totally oxygen-free environment. after 7 days growth in the light or dark under n(2), e. crus-galli var. oryzicola produces a 2- to 3-centimeter nonpigmented shoot.ethanol, malate, and lactate were measured in seeds germinated under n(2) and air, and compared with changes in the activities of alcohol dehydrogenase, malate dehydrogenase, nadp-malic enzyme, and phosphoenolpyruvate carboxylase. ...198116661863
plastid development in seedlings of echinochloa crus-galli var. oryzicola under anoxic germination conditions.plastid development in the primary leaf of echinochloa crus-galli (l.) beauv. var. oryzicola (vasing.) ohwi was followed during 5 d of anoxic germination and growth. plastids develop slowly from simple spheroidal proplastids into larger pleomorphic plastids with several stromal membranes and many peripheral membrane vesicles. a small prolamellar body is present at 96 h with perforated (pro)thylakoids extending into the stroma. changes in starch grains and plastoglobuli are evidence of carbohydra ...198224271619
development of photosynthetic activity following anaerobic germination in rice-mimic grass (echinochloa crus-galli var oryzicola).shoots of anaerobically germinated echinochloa crus-galli var oryzicola are nonpigmented whether germinated in light or dark, and chlorophyll synthesis is minimal for the first 12 to 18 hours of greening after exposure to ambient conditions. when chlorophyll development is compared between greening anoxic and etiolated shoots, there is a 100-fold difference in chlorophyll levels at 8 hours, an 8-fold difference at 24 hours, but roughly equal amounts at 60 hours. the chlorophyll a/b ratio approac ...198316663217
germination of echinochloa crus-galli (barnyard grass) seeds under anaerobic conditions : respiration and response to metabolic inhibitors.echinochloa crus-galli l. beauv., a rice-field weed, can germinate and grow for extended periods of time in an anaerobic environment. compared to pea, which does not germinate under anaerobiosis, the evolution of co(2) in echinochloa and rice is lower and the peak rate of co(2) evolution is delayed when germinated without oxygen. the plants studied also differ with respect to their respiration ratio ([co(2)] n(2)/[co(2)] air) and metabolism used during the early stages of germination. echinochlo ...198316663086
anaerobiosis in echinochloa crus-galli (barnyard grass) seedlings : intermediary metabolism and ethanol tolerance.tolerance to ethanol and the ability to metabolize key intermediary substrates under anaerobiosis were studied in echinochloa crus-galli (l.) beauv. var oryzicola seeds to further characterize the mechanisms which enable it to germinate and grow without o(2).our results indicate that e. crus-galli var oryzicola possesses an inherently high tolerance to ethanol and is able to metabolize low levels of ethanol in the absence of o(2). concentrations of ethanol 45-fold greater than endogenous levels ...198316662979
quantitative structure-activity relationships for 2-[(phenylmethyl)sulfonyl]pyridine 1-oxide herbicides.phenyl-substituted analogues of 2-[(phenylmethyl)sulfonyl]pyridine 1-oxide preemergent herbicides were examined in order to determine quantitative relationships between structure and activity against the following three weed species: switch grass (panicum virgatum l.), barnyard grass (echinochloa crusgalli l. beauv.), and green foxtail (setaria viridis l. beauv.). analogues were chosen to provide maximum parameter orthogonality. regression analysis yielded structure-activity relationships wherei ...19836834380
somatic embryogenesis inechinochloa crusgalli.a white, compact embryogenic tissue was obtained from young inflorescence segments ofechinochloa crusgalli (barnyard grass) cultured on murashige and skoog's medium containing various concentrations and combinations of 2,4-dichlorophenoxyacetic acid and 6-benzylaminopurine. histological and scanning electron microscopic studies revealed that the white compact callus contained embryoids in various stages of development. typical embryoids were bipolar and possessed scutella, coleoptiles and coleor ...198424253431
effects of temperature and co2 enrichment on kinetic properties of phospho-enol-pyruvate carboxylase in two ecotypes of echinochloa crus-galli (l.) beauv., a c4 weed grass species.two populations of echinochloa crus-galli (québec, mississippi) were grown at the duke university phytotron under 2 thermoperiods (28°/22°c, 21°/15°c day/night) and 2 co2 regimes (350 and 675 μl l(-1)). thermostability, energy of activation (e a ),k m (pep), k m (mg(++)), and specific activity of phospho-enol-pyruvate carboxylase (pepc) were analyzed in partially purified enzyme preparations of plants grown for 5 weeks. thermostability of pepc from extracts (in vitro) and leaves (in situ) was si ...198428311006
effects of temperature and co(2) enrichment on carbon translocation of plants of the c(4) grass species echinochloa crus-galli (l.) beauv. from cool and warm environments.plants of echinochloa crus-galli from québec and mississippi were grown under two thermoperiods (28 degrees c/22 degrees c, 21 degrees c/15 degrees c) and two atmospheric co(2) concentrations (350 and 675 microliters per liter) to examine possible differential responses of northern and southern populations of this c(4) grass species. translocation was monitored using radioactive tracing with short-lived (11)c. co(2) enrichment induced a decrease in the size of the export pool in plants of both p ...198416663733
low night temperature effect on photosynthate translocation of two c4 grasses.translocation of assimilates in plants of echinochloa crus-galli, from quebec and mississippi, and of eleusine indica from mississippi was monitored, before and after night chilling, using radioactive tracing with the short-life isotope (11)c. plants were grown at 28°/22°c (day/night temperatures) under either 350 or 675 μl·l(-1) co2. low night temperature reduced translocation mainly by increasing the turn-over times of the export pool. e. crus-galli plants from mississippi were the most suscep ...198528311562
isolation ofc-glycosylflavones as probing stimulant of planthoppers in rice plant.three species of planthopper,nilaparvata lugens,sogatella furcifera, andlaodelphax striatellus, showed characteristic behavior of stylet probing in parenchymal tissues of plants. feeding experiments of planthoppers on aqueous sucrose solution containing the extract of rice plants or barnyard grass revealed the presence of the stimulant for the probing behavior in the plant tissues. eightc-glycosylflavones which stimulated stylet probing were isolated from rice plants. four of them were identifie ...198524310066
phytotoxic properties of nordihydroguaiaretic acid, a lignan fromlarrea tridentata (creosote bush).the phytotoxic properties of nordihydroguaiaretic acid (ndga) isolated from creosote bush,larrea tridentata (zygophyllaceae), were examined. ndga dramatically reduces the seedling root growth of barnyard grass, green foxtail, perennial ryegrass, annual ryegrass, red millet, lambsquarter, lettuce, and alfalfa, and reduces the hypocotyl growth of lettuce and green foxtail. it has no effect on the germination of lettuce seeds. ndga almost certainly contributes to the observed allelopathic nature of ...198524311094
effect of leaf detachment on chlorophyll fluorescence during chilling experiments.the effect of leaf detachment on chlorophyll fluorescence was analyzed for zea mays, cucumis sativus, phaseolus vulgaris, and echinochloa crus-galli. results clearly indicate that detachment hastens the decrease in chlorophyll fluorescence during the course of chilling experiments. for maize and bean, the activity of photosystem ii of chloroplasts isolated from detached leaves is lower than that of chloroplasts isolated from attached leaves. there are also large differences in ionic loss between ...198516664345
allelopathic polyacetylenes fromcentaurea repens (russian knapweed).the allelopathic weed russian knapweed (centaurea repens) was found to contain polyacetylenes viii-xiv in the roots. dose vs. response of the root length elongation against lettuce, alfalfa, barnyard grass, and red millet showed ix to be active. closely related isomers were not active. examination of the soil surrounding the russian knapweed roots revealed the presence of ix in sufficient concentration to have an appreciable effect on the surrounding plant community.198624307103
effect of low temperature on the photosynthetic metabolism of the c4 grass echinochloa crus-galli.co2 curves of photosynthesis and activities of the four c4 enzymes and ribulose bisphosphate carboxylase (rubpc) were compared in two populations of the c4 grass echinochloa crus-galli from contrasting thermal environments (québec and mississippi). analyses were conducted both before and after 14 h of chilling at 7°c under high light conditions. this comparison provides the opportunity to assess which steps of the c4 pathway are more susceptible to become limiting at low temperatures. both popul ...198628311607
activities of isolated mitochondria and mitochondrial enzymes from aerobically and anaerobically germinated barnyard grass (echinochloa) seedlings.activity of mitochondria isolated from whole seedlings of echinochloa crus-galli (l.) beauv. var oryzicola germinated under aerobic and anaerobic conditions for 5 to 7 days was investigated. mitochondria from both treatments exhibited good respiratory control and adp/o ratios. although o(2) uptake was low in anaerobic mitochondria, activity rapidly increased when the seedlings were transferred to air. mitochondria from both aerobically and anaerobically grown seedlings of e. crus-galli var oryzi ...198716665723
weed hosts of meloidogyne arenaria and m. incognita common in tobacco fields in south carolina.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 < 0.05) among weed species. chenopodium album, euphorbia maculata, and vicia villosa were good hosts of m. arenaria. amaranthus palmeri, rumex crispus, amaranthus hybridus, ambrosia artemisiifolia, lpomoea hederacea var. integriuscula, setaria lutescens, sida spinosa, portulaca ol ...198819290313
effects of temperature and co2 enrichment on kinetic properties of nadp(+)-malate dehydrogenase in two ecotypes of barnyard grass (echinochloa crus-galli (l.) beauv.) from contrasting climates.the apparent energy of activation (e a), michaelis-menten constant (k mfor oxaloacetate), v max/k mratios and specific activities of nadp(+)-malate dehydrogenase (nadp(+)-mdh; ec 1.1.1.82) were analyzed in plants of barnyard grass from québec (que) and mississippi (miss) acclimated to two thermoperiods 28/22°c, 21/15°c, and grown under two co2 concentrations, 350 μl l(-1) and 675 μl l(-1). e avalues of nadp(+)-mdh extracted from que plants were significantly lower than those of miss plants. k mv ...198928312170
differences in the anaerobic lactate-succinate production and in the changes of cell sap ph for plants with high and low resistance to anoxia.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 cer ...198916666751
changes in the composition and synthesis of proteins in cellular membranes of echinochloa crus-galli (l.) beauv. seeds during the transition from dormancy to germination.the effect of alcohols which stimulate or have no effect on germination on the composition and synthetic pattern of proteins in the cellular membranes of echinochloa crus-galli (l.) beauv. seeds was studied. imbibition of dry seeds was accompanied by an increase in the synthesis of proteins and by synthesis of new proteins in their intracellular membranes. the transition of the seeds from a dormant to a nondormant state was associated with synthesis of specific proteins and a decrease in content ...199016667293
mitochondrial enzymes in aerobically and anaerobically germinated seedlings of echinochloa and rice.activities of tricarboxylic acid (tca) cycle enzymes in seedlings of barnyard grass (echinochloa phyllopogon (stapf.) koss) and rice (oryza sativa l.) germinated under aerobic and anaerobic conditions were investigated. in e. phyllopogon, development of tca-cycle enzyme activities during 10 d of anoxia generally paralleled those in air, although at lower rates. after 5 d, e. phyllopogon seedlings germinating under n2 exhibited 50-80% of the activity of seedlings grown in air, except for 2-oxoglu ...199124194241
2,2'-oxo-1,1'-azobenzene: selective toxicity of rye (secale cereale l.) allelochemicals to weed and crop species: ii.three allelochemicals from rye or its breakdown products were evaluated for activity on garden cress (lepidum sativum l.), barnyardgrass [echinochloa crus-galli (l.) beauv.], cucumber (cucumis sativus l.), and snap bean (phaseolus vulgaris l.). 2,4-dihydroxy-1,4(2h)-benzoxazin-3-one (diboa), 2(3h)-benzoxazolinone (boa), and 2,2'-oxo-1,1'-azobenzene (azob) were all applied singly at 50, 100, and 200 ppm and in two- and three-way combinations each at 50 and 100 ppm. azob at 100 and 200 ppm produce ...199124258430
soil transformation of 2(3h)-benzoxazolone of rye into phytotoxic 2-amino-3h-phenoxazin-3-one.nonsterile soil transforms the rye metabolite 2(3h)-benzoxazolone (boa) into 2-amino-3h-phenoxazin-3-one, which is an order of magnitude more toxic to barnyard grass than benzoxazolone. benzoxazolone was recovered unchanged from sterile soil. however,o-aminophenol is converted to aminophenoxazinone by both sterile and nonsterile soil in the presence of air. aminophenoxazinone is probably produced by microbial hydrolysis of benzoxazolone intoo-aminophenol, which is oxidized to aminophenoxazinone ...199224254712
allelopathy ofsasa cernua.sasa (sasa cernua makino) is a very serious weed pest. its allelopathy was studied using lettuce, wheat, timothy, and green amaranth as testing species. cultured in the rhizosphere soil ofsasa cernua, the seedlings were inhibited by 42-80% compared with the controls cultured in normal soil and vermiculite. the phenolic fraction extracted with 1 m naoh from the rhizosphere soil ofs. cernua caused significant inhibitions on the seed germination and seedling growth of lettuce, timothy, green amaran ...199224254720
soil transformation of wheat and corn metabolites mboa and dim2boa into aminophenoxazinones.the defensive cyclic hydroxamates 7-methoxy-2,4-dihydroxy-1,4(2h)-benzoxazin-3-one (dimboa) and 7,8-dimethoxy-2,4-dihydroxy-1,4(2h)-benzoxazin-3-one (dim2boa) of wheat and corn are transformed in nonsterile soil, via 6-methoxy-2(3h)-benzoxazolone (mboa) and 6,7-dimethoxy-2(3h)-benzoxazolone (m2boa) respectively, into 2-amino-7-methoxy-3h-phenoxazin-3-one and 2-amino-4,6,7-trimethoxy-3h-phenoxazin-3-one. the soil transformation is similar of that undergone by the rye metabolite 2(3h)-benzoxazolon ...199324248702
tricolorin a, major phytogrowth inhibitor from ipomoea tricolor.the allelopathic potential of ipomoea tricolor (convolvulaceae), used in mexican traditional agriculture as a weed controller, has been demonstrated by measuring the inhibitory activity of organic extracts on seedling growth of amaranthus leucocarpus and echinochloa crus-galli. bioactivity-directed fractionation of the active chcl3 extract led to the isolation of the allelopathic principle, which turned out to be a mixture of the so-called "resin glycosides" of convolvulaceous plants. the struct ...19938496705
maternally-induced modification of progeny phenotypes in the c4 weed echinochloa crus-galli: an analysis of seed constituents and performance.to clarify the physiological basis of maternal inheritance we examined the effect of the thermal environment of mother plants of echinochloa crus-galli on subsequent seed mass, content and quality. the same plants were grown in a warm and a cold environment until seeds were produced and, since e. crus-galli is a highly inbred species, the observed variation in seed production was a purely plastic response to the environment. when mother plants were grown at high temperature, average seed mass, v ...199328313439
constitutive and inducible aerobic and anaerobic stress proteins in the echinochloa complex and rice.anaerobic stress resulted in a change in the protein accumulation patterns in shoots of several echinochloa (barnyard grass) species and oryza sativa (l.) (rice) as resolved by two-dimensional gel electrophoresis. of the six echinochloa species investigated, e. phyllopogon (stev.) koss, e. muricata (beauv.) fern, e. oryzoides (ard.) fritsch clayton, and e. crus-galli (l.) beauv. are tolerant of anaerobiosis and germinate in the absence of oxygen, as does rice. in contrast, e. crus-pavonis (h.b.k ...199312231678
inhibition of barnyardgrass 4-hydroxyphenylpyruvate dioxygenase by sulcotrione.4-hydroxyphenylpyruvate dioxygenase (ec 1.13.11.27) was partially purified from barnyardgrass (echinochloa crus-galli l.) leaves and assayed by high-performance liquid chromatography analysis of product formation or by the capture of released 14co2. the bleaching herbicide sulcotrione [2-(2-chloro-4-methanesulfonylbenzoyl)-1,3-cyclohexanedione] was shown to be a potent, linear competitive inhibitor of 4-hydroxyphenylpyruvate dioxygenase. kinetic analyses determined that the km for the substrate, ...199412232420
biochemically active sesquiterpene lactones from ratibida mexicana.bioactivity-directed fractionation of the methanol extract of the roots of ratibida mexicana resulted in the isolation of two bioactive sesquiterpene lactones, isoalloalantolactone and elema-1,3,11-trien-8,12-olide. both compounds caused a significant inhibition of the radicle growth of amaranthus hypochondriacus and echinochloa crus-galli, exerted moderate cytotoxic activity against three different solid tumour cell lines and inhibited significantly the radial growth of three phytopathogenic fu ...19957546556
geographic variation in seed dormancy among populations of echinochloa crus-galli.in 1991-1993, we investigated the incidence of seed dormancy in 25 local populations of barnyard grass, echinochloa crus-galli (l.) p.beauv., in the western czech republic. the percentage of germination after 4 months afterripening of dry seeds at 25°c varied between 0.0 and 83.6%. although there were significant annual differences in the percentage of germination at some localities, typical proportions of dormant seeds persisted over 3 years at field sites where the seed bank was not disturbed. ...199628307856
localisation of sucrose-phosphate synthase and starch in leaves of c4 plants.the activity and intercellular distribution of sucrose-phosphate synthase (sps; ec 2.4.1.14) were determined in fully expanded leaves from a range of c4 plants. in zea mays l. and atriplex spongiosa f. muell., sps was located almost exclusively in the mesophyll cells. in other species, sps was found in both cell types, with the activity in the bundle sheath cells ranging from 5% of the total leaf activity in echinochloa crus-galli (l.) beauv. to 35% in sorghum bicolor moench. at the end of the l ...19979177054
populations of xylella fastidiosa in plants required for transmission by an efficient vector.abstract xylella fastidiosa, a xylem-limited bacterium that causes pierce's disease (pd) of grapevine and other diseases, is transmitted efficiently by xylem-feeding leafhoppers. acquisition of a pd strain of x. fastidiosa by the blue-green sharpshooter (bgss) from five plant host species-grapevine (vitis vinifera), himalayan blackberry (rubus discolor), california mugwort (artemisia douglasiana), watergrass (echinochloa crus-galli), and bermuda grass (cynodon dactylon)-was tested at various tim ...199718945018
n-terminal amino acid sequences of prolamins encoded by the alleles at the pro1 and pro2 loci in foxtail millet, setaria italica (l.) p. beauv.n-terminal amino acid sequences of six prolamins encoded by seven alleles at two loci, pro1 and pro2, of foxtail millet (setaria italica (l.) p. beauv.) were analyzed and compared with other prolamins of subfamily panicoideae. based on the n-terminal amino acid sequences, band 3 (the prolamin purified from band 3) which is controlled by an allele at the pro1 locus and bands 1, 2, 4, 5 and 6 which are controlled by alleles at the pro2 locus could be classified into three groups. band 3 was found ...199910791027
allelopathic substance exuded from a serious weed, germinating barnyard grass (echinochloa crus-galli l.), roots.the allelopathy of a serious weed, barnyard grass (echinochloa crus-galli l.), was investigated. root exudates of young barnyard grass showed allelopathic effects and plant-selective activity and inhibited root elongation of all plants tested. with respect to shoot growth, the exudates did not show inhibition of barnyard grass only. the allelopathic substance was isolated and identified as p-hydroxymandelic acid by nmr. p-hydroxymandelic acid strongly inhibited shoot growth and root elongation o ...199910552134
estimation of base temperatures for nine weed species.experiments were conducted to test several methods for estimating low temperature thresholds for seed germination. temperature responses of nine weeds common in annual agroecosystems were assessed in temperature gradient experiments. species included summer annuals (amaranthus albus, a. palmeri, digitaria sanguinalis, echinochloa crus-galli, portulaca oleracea, and setaria glauca), winter annuals (hirschfeldia incana and sonchus oleraceus), and conyza canadensis, which is classified as a summer ...200010938833
evaluation of propargyl bromide for control of barnyardgrass and fusarium oxysporum in three soils.with the scheduled phasing out of methyl bromide, there is an urgent need for alternatives. we evaluated the efficacy of propargyl bromide as a potential replacement for methyl bromide for the control of barnyardgrass (echinochloa crus-galli) and fusarium oxysporum in an arlington sandy loam, a carsitas loamy sand and a florida muck soil. soil was mixed with barnyardgrass seeds or f oxysporum colonized on millet seeds, and treated with propargyl bromide at a range of concentrations. the mortalit ...200111561402
weeds as a source of plant growth promoting rhizobacteria in agricultural soils.the influence of plant growth promoting (pgp) activity of bacterial communities recovered from each of six weed species (barnyard grass (echinochloa crusfalli (l.) beauv.), corn spurrey (spergula arvensis l.), goldenrod (sonchus sp.), italian ryegrass (lolium multiflorum l.), lamb's-quarters (chenopodium album l.), and quack grass (agropyron repens (l.) beauv.)) was examined in relation to the effect it had on the growth of the potato cultivar russet burbank. bacterial species composition and co ...200111766050
chemical control of perennial and annual weeds in herbicide resistant soybean crops.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 ...200112425098
designing herbicide formulation characteristics to maximize efficacy and minimize rice injury in paddy environments.mathematical descriptors, coupled with experimental observations, are used to quantify differential uptake of an experimental herbicide in japonica and indica rice (oryza sativa, non-target) and barnyardgrass (echinochloa crus-galli, target). partitioning, degradation, plant uptake and metabolism are described using mass-balance conservation equations in the form of kinetic approximations. estimated environmental concentrations, governed by the pesticide formulation, are described using superimp ...200111407023
phytotoxic compounds from prionosciadium watsoni.bioassay-guided fractionation of a phytotoxic extract of prionosciadium watsoni led to the isolation of three new pyranocoumarins and two pyranochromones. the new compounds were characterized as propionic acid (9r,10r)-9-acetoxy-8,8-dimethyl-9,10-dihydro-2h,8h-benzo[1,2-b:3,4-b']dipyran-2-one-10-yl ester (1), isobutyric acid (9r,10r)-9-hydroxy-8,8-dimethyl-9,10-dihydro-2h,8h-benzo[1,2-b:3,4-b']dipyran-2-one-10-yl ester (2), isobutyric acid (9r)-8,8-dimethyl-9,10-dihydro-2h,8h-benzo[1,2-b:3,4-b'] ...200212088423
a bleaching herbicidal activity of methoxyhygromycin (mhm) produced by an actinomycete strain streptomyces sp. 8e-12.to screen bioherbicidal isolates and evaluate herbicidal activity of methoxyhygromycin (mhm) produced by streptomyces sp. 8e-12.200312753247
essential oils from mediterranean lamiaceae as weed germination inhibitors.the essential oils obtained from rosemary (rosmarinus officinalis l.), thyme (thymus vulgaris l.), and savory (satureja montana l.) and the four monoterpenes that are their major constituents have been analyzed by gc and gc-ms and tested for their allelopathic properties on the seeds of three different annual weeds (chenopodium album, portulaca oleracea, and echinochloa crus-galli) and three crops (raphanus sativus, capsicum annuum, and lactuca sativa), with the aim to evaluate in vitro their po ...200314518938
bioactivities of nostocine a produced by a freshwater cyanobacterium nostoc spongiaeforme tistr 8169.a freshwater cyanobacterium, nostoc spongiaeforme tistr 8169, synthesizes and releases a violet pigment, nostocine a, into medium. we examined the bioactivity of nostocine a to several model organisms breeding with n. spongiaeforme in the natural environment. to microalgae, nostocine a exhibited growth inhibitory activity comparable to paraquat, and the activity tended to be stronger to green algae than to cyanobacteria. nostocine a also exhibited strong inhibitory activity to the root elongatio ...200316233448
phytotoxic compounds from flourensia cernua.bioassay-directed fractionation of a ch(2)cl(2)-meoh (1:1) extract of the aerial parts of flourensia cernua led to the isolation of three phytotoxic compounds, namely, dehydroflourensic acid (1), flourensadiol (2) and methyl orsellinate (3). dehydroflourensic acid is a new natural product whose structure was established by spectral means. in addition, the known flavonoid ermanin and seven hitherto unknown gamma-lactones were obtained, these being tetracosan-4-olide, pentacosan-4-olide, hexacosan ...200312946427
[genes mapping on rice allelopathy against barnyardgrass].by using the relay seeding technique with slight modification, a population of 134 recombinant inbred lines (rils) derived from a cross between indica rice (oryza sativa l.) cultivar zhong 156 x gumei 2 and contained 168 dna markers covering all 12 chromosomes with 1447.9 cm spans was employed to evaluate the rice allelopathic effect on barnyardgrass [echinochloa crus-galli (i.) beauv.]. the phenotyping values of the biomass of barnyardgrass infested with rice materials were employed to map the ...200315031929
genetic and biochemical analysis of anaerobically-induced enzymes during seed germination of echinochloa crus-galli varieties tolerant and intolerant of anoxia.to compare the regulation of anaerobic metabolism during germination in anoxia-tolerant and intolerant plants, enzymes associated with anaerobic metabolism such as sucrose synthase, aldolase, enolase, pyruvate decarboxylase (pdc), alcohol dehydrogenase (adh), and aldehyde dehydrogenase (aldh) were assayed in two varieties of echinochloa crus-galli, formosensis (tolerant) and praticola (intolerant). the initial and intervening enzymes of the pathway (sucrose synthase and aldolase) and enzymes in ...200312709489
construction of a comparative rflp map of echinochloa crus-galli toward qtl analysis of flooding tolerance.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 ...200415067384
[interference of allelopathic rice cultivars on barnyardgrass under different water irrigation and rice plant density].pot culture experiments were conducted to examine the effects of water irrigation and rice plant density on the interference of allelopathic rice on barnyardgrass (echinochloa crus-galli). the results showed that under water irrigations, allelopathic rice cultivars xiayitiao, gumei 2 and zhong 156 significantly reduced the plant height of barnyardgrass than non-allelopathic rice cultivars xiushui 63 and chunjiang 11. barnyardgrass plants grew shorter as rice plant density increased. allelopathic ...200415669488
ek-2612, a new cyclohexane-1,3-dione possessing selectivity between rice (oryza sativa) and barnyardgrass (echinochloa crus-galli).a newly synthesized experimental compound, ek-2612 is one of the class of cyclohexane-1,3-diones which are commonly known to be grasskillers. a greenhouse study was conducted to evaluate the herbicidal performances of ek-2612 on several grass species in comparison with tralkoxydim, a commercialized cyclohexanedione derivative. like tralkoxydim, the compound ek-2612 showed excellent control efficacy on most grass weeds tested through foliar application rates between 250 and 63 g ai ha(-1). unlike ...200415382506
two compounds from allelopathic rice accession and their inhibitory activity on weeds and fungal pathogens.a flavone (5,7,4'-trihydroxy-3',5'-dimethoxyflavone), a cyclohexenone (3-isopropyl-5-acetoxycyclohexene-2-one-1) and a liquid mixture of low polarity, containing long-chain and cyclic hydrocarbons, were isolated from leaves of allelopathic rice accession pi 312777 using column chromatography. their structures and constituents were identified by means of hr-ms, nmr and gc/ms analyses, respectively. bioassays showed that both the flavone and cyclohexenone significantly inhibited the growth of weed ...200415110693
photosynthetic and growth responses of zea mays l and four weed species following post-emergence treatments with mesotrione and atrazinet.we compared photosynthesis and growth of zea mays l (corn) and four weed species, setaria viridis (l) beauv (green foxtail), echinochloa crus-galli (l) beauv (barnyardgrass), abutilon theophrasti medic (velvetleaf), and amaranthus retroflexus l (redroot pigweed), following foliar applications with atrazine, mesotrione, or a combination of atrazine and mesotrione in two greenhouse experiments. plant responses to the three herbicide treatments were compared with responses of untreated plants (cont ...200415532681
allelochemicals from stauranthus perforatus, a rutaceous tree of the yucatan peninsula, mexico.aqueous leachates and a chcl3-meoh (1:1) extract of roots of stauranthus perforatus showed a significant phytotoxic effect on amaranthus hypochondriacus and echinochloa crus-galli. bioassay-directed fractionation of the active organic extract led to the isolation and characterization of ten secondary metabolites, which included two pyranocoumarins [xanthyletin (1) and 3-(1',1'-dimethylallyl)-xanthyletin (2)], four furanocoumarins [chalepensin (3), ammirin (4), chalepin (5) and 2'-isopropyl-psora ...200515694456
[allelopathic effects of cymbopogon citratu volatile and its chemical components].this paper studied the allelopathic effects of cymbopogon citratus volatile on the seed germination and seedling growth of corn and barnyard grass (echinochloa crusgalli) in field and in obturator, and analyzed the chemical components of the volatile with spme and gc-ms. the results of bio-assay indicated that the germination rate of corn or barnyard grass intercropped with c. citrate or enclosed in obturator with fresh c. citratus had no significant difference from the control, but the seedling ...200516011184
translation of in vitro inhibition by marine natural products of the c4 acid cycle enzyme pyruvate p(i) dikinase to in vivo c4 plant tissue death.marine organism derived extracts, previously identified as containing compounds that inhibited the c4 acid cycle enzyme pyruvate p(i) dikinase (ppdk), were assessed for their ability to exhibit an effect on the c4 plants digitaria ciliaris and echinochloa crus-galli. oxygen electrode studies revealed that over half of these extracts inhibited c4 acid driven photosynthesis in leaf slices. seventeen extracts had a deleterious effect on c4 plants in vivo within 24 h, whereas 36 caused an observable ...200515884807
the potential efficiency of irrigation management and propargyl bromide in controlling three soil pests: tylenchulus semipenetrans, fusarium oxysporum and echinochloa crus-galli.propargyl bromide (3-bromopropyne, 3bp) is a potential alternative for methyl bromide. little information is available about its efficiency in controlling pests. the purpose of this paper is to estimate the 3bp dose required for killing three pests and to compare the efficiency of water management approaches to that of fumigation. the pests, fusarium oxysporum schlecht (fungus), echinochloa crus-galli (l) beauv (grass) and tylenchulus semipenetrans cobb (nematode) were exposed to different 3bp c ...200515912563
antifungal activity against plant pathogenic fungi of chaetoviridins isolated from chaetomium globosum.the chaetomium globosum strain f0142, which was isolated from barnyard grass, showed potent disease control efficacy against rice blast (magnaporthe grisea) and wheat leaf rust (puccinia recondita). two antifungal substances were purified from broth from this organism and identified as chaetoviridins a and b. chaetoviridin a exhibited higher antifungal activity than chaetoviridin b against plant pathogenic fungi both in vitro and in vivo. treatment with chaetoviridin a at 62.5 microg/ml suppress ...200516209910
involvement of reactive oxygen species generated from melanin synthesis pathway in phytotoxicty of l-dopa.l-dopa is an active allelochemical that inhibits plant growth. to determine whether the phytotoxicity is due to the reactive oxygen species generated during its oxidation to melanin, oxidative damage, melanin accumulation, and the effect of antioxidants on its phytotoxicity were examined in l-dopa-tolerant (barnyard grass) and -susceptible (lettuce) plants, and in suspension-cultured carrot cells. l-dopa suppressed root elongation in lettuce compared to barnyard grass. levels of melanin and thio ...200515856781
synthesis, crystal structure and herbicidal activity of mimics of intermediates of the kari reaction.two mimics of the intermediate in the reaction catalyzed by ketol-acid reductoisomerase (kari) were synthesized. their structures were established on the basis of elemental analyses, ir, 1h nmr and gc/mass detector. the crystal structure of compound 2 was found to be a substituted dioxane, formed by the condensation of two molecules. the two compounds showed some herbicidal activity on the basis of tests using rape root and barnyard grass growth inhibition. however, the herbicidal effect was wea ...200515751008
5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)- 1,2-isoxazoline as a useful rice herbicide.5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)-1,2-isoxazoline derivative was synthesized, and its herbicidal activity was assessed under glasshouse and flooded paddy conditions. 5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)-1,2-isoxazoline demonstrated good rice selectivity and potent herbicidal activity against annual weeds at 125 g of a.i. ha(-1) under greenhouse conditions. soil application of this compound showed complete control of barnyard-grass to ...200516248565
[prevention efficiency of exserohilum monoceras with chemical herbicides against echinochloa crus-galli in paddy field].this paper studied the impact of several herbicides on the conidium germination of exserohilum monoceras strain x27 in petri dish, and the synergistic effects of the pathogen and chemical herbicide quinclorac or propanil against echinochloa crus-galli in greenhouse. the prevention efficiency of the tank-mixture of pathogen and quinclorac was also evaluated in paddy field. the results showed that test herbicides except quinclorac and bensulfulfuronmethyl could inhibit conidium germination and hyp ...200516180763
allelopathic potential of robinia pseudo-acacia l.robinia pseudo-acacia l. (black locust) is a nonindigenous species currently invading the central part of japanese grasslands. several allelochemicals were identified and characterized from the leaf tissue. the growth of both radicle and hypocotyl in the tested species (barnyard grass, white clover, lettuce, and chinese cabbage) was reduced when grown in soil mixed with the leaves of r. pseudo-acacia at various concentrations. aqueous leaf extracts, when bioassayed, exhibited a significant suppr ...200516132219
[inhibitory effects of allelopathic rice materials on echinochloa crus-galli and related field weeds].by using the modified relay seeding technique, more than 10 allelopathic rice materials were obtained from 500 rice germplasm, and their allelopathic inhibitory effects on weeds were evaluated under field condition. the results showed that under direct-seeded condition, the allelopathic rice materials gumei 2, xiayitiao, jizaoxian, ganzaoxian and shangnuo 1 had more obvious inhibitory effects on echinochloa crus-galli than non-allelopathic rice materials xiushui 63 and chunjiang 11, while the al ...200516011176
structure-activity relationship studies of benzoxazinones and related compounds. phytotoxicity on echinochloa crus-galli (l.) p. beauv.echinochloa crus-galli (e. crus-galli; barnyardgrass) is a weed widely distributed. it constitutes a serious weed problem in 42 countries and has been found in at least 27 more. it is the world's main weed of rice affecting up to 36 crops worldwide. several biotypes of this plant, with resistance to herbicides with different modes of action have evolved. in our ongoing studies regarding the potential application of benzoxazinones and their soil degradation products for weed control, a complete s ...200515913298
determination of antagonism between cyhalofop-butyl and other rice (oryza sativa) herbicides in barnyardgrass (echinochloa crus-galli).herbicide antagonism is defined as the reduction of control of certain weeds as the result of applying mixtures of two or more herbicides. cyhalofop-butyl, a graminicide used for postemergence grass weed control in rice, is antagonized by some rice herbicides when applied simultaneously. the result of this type of antagonism usually results in decreased control of grass weeds. research has shown that herbicide antagonism between graminicides and other herbicides may be caused by different mechan ...200515884840
evaluation of allelopathic potential and quantification of momilactone a,b from rice hull extracts and assessment of inhibitory bioactivity on paddy field weeds.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, monoch ...200616569039
weed control in rice with metham-sodium.metam-sodium is a soil fumigant with herbicidal properties. a field experiment was conducted in 2000 at copiano (pavia, italy) to determine the efficacy of three rates of metam-sodium (300, 450 and 600 l/ha) at three different planting times (5, 12 and 18 days after chemical treatments) for the control of weeds in rice cultivation. the study mainly focused on the control of red rice (oryza sativa var. selvatica), a weed which is worldwide distributed in rice fields and difficult to eradicate tes ...200617390826
carboxylesterase activities toward pesticide esters in crops and weeds.proteins were extracted from maize, rice, sorghum, soybean, flax and lucerne; the weeds abutilon theophrasti, echinochloa crus-galli, phalaris canariensis, setaria faberii, setaria viridis, sorghum halepense and the model plant arabidopsis thaliana and assayed for carboxylesterase activity toward a range of xenobiotics. these included the pro-herbicidal esters clodinafop-propargyl, fenoxaprop-ethyl, fenthioprop-ethyl, methyl-2,4-dichlorophenoxyacetic acid (2,4-d-methyl), bromoxynil-octanoate, th ...200617078983
a large-scale field study of transgene flow from cultivated rice (oryza sativa) to common wild rice (o. rufipogon) and barnyard grass (echinochloa crusgalli).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, t ...200617309736
effect of fertilization on the weediness of maize in a long-term field experiment.we carried our examination in a long-term fertilization field experiment in 2005. in the experiment we had opportunity to compare the weediness in npk and npk + fym1 treatments, and we could study the effect of increasing n dosis on the weeds and maize. the bi-factorial trial was arranged in split plot design with three replications. the weed survey was made 25 days after seeding in the 27th of may. for the weed survey the balázs-ujvárosi method was applied. after the weed survey we collected al ...200617390821
[allelopathic potential and physiological mechanism of oryza sativa l. under phosphorus deficiency stress].in this paper, allelopathic rice pi312777 (pi) and non-allelopahtic rice lemont (le) were grown in the nutrient solution with two levels of phosphorus (p) supply, and their allelopathic effects on echinochloa crus-galli l. were studied. the results showed that under phosphorous deficiency stress, the inhibitory effect of pi on e. crus-galli root growth had an obvious increase. after growing in the nutrient solution with low p supply (0.5 mg x l(-1)) for 5, 10 and 15 days, the inhibitory rate of ...200617269328
a quantitative structure-activity relationship study of herbicidal analogues of alpha-hydroxy-substituted 3-benzylidenepyrrolidene-2,4-diones.a series of pyrrolidine-2,4-dione and piperidine-2,4-dione derivatives were prepared and evaluated for their herbicidal activities where some of these compounds exhibited good bioactivity against echinochloa crus-galli in comparison with sulcotrione. quantitative structure-activity relationship studies were performed on these compounds using physicochemical parameters (hydrophobic, electronic, and taft) as independent parameters and herbicidal activity as a dependent parameter, where herbicidal ...200616968083
identification of phytotoxic substances from early growth of barnyard grass (echinochloa crusgalli) root exudates.barnyard grass is a problematic weed worldwide. it competes with crops and causes reduction in crop yields. in this study, barnyard grass suppressed rice emergence, and the degree of rice inhibition was proportional to the density of barnyard grass. root exudates of barnyard grass reduced germination and growth of lettuce, rice, and monochoria. fifteen compounds potentially involved in the phytotoxic activities of barnyard grass were isolated and identified, including phenolics, long-chain fatty ...200616718576
soil dissipation and biological activity of metolachlor and s-metolachlor in five soils.the resolved isomer of metolachlor, s-metolachlor, was registered in 1997. new formulations based primarily on the s-metolachlor isomer are more active on a gram for gram metolachlor basis than formulations based on a racemic mixture of metolachlor containing a 50:50 ratio of the r and s isomers. the labelled use rates of s-metolachlor-based products were reduced by 35% to give equivalent weed control to metolachlor. however, several companies have recently registered new metolachlor formulation ...200616671061
bioactive steroids from oryza sativa l.rice is one of the most interesting crops in the world from both the social and the economic point of views. the monoculture practices along with the heavy use of herbicides are characteristic of modern agriculture and are inducing the appearance of tolerant and/or herbicide resistant weed biotypes. this is the case the world's main weed of rice barnyardgrass (echinochloa crus-galli). alternative strategies for weed suppression consist of the use of chemicals from rice due to necessity of obtain ...200616620896
pentacyclic triterpenes with selective bioactivity from sebastiania adenophora leaves, euphorbiaceae.six known pentacyclic triterpenes possessing oleanane, lupane, or taraxerane-type skeletons were isolated from the leaves of sebastiania adenophora (euphorbiaceae) and are reported for the first time in this species. these compounds include 3-epi-beta-amyrin, beta-amyrinone, 3-epi-lupeol, lupenone, taraxerol, and taraxerone. structures were elucidated by comparison with literature data. the bioactivities of these compounds were tested on the root growth of amaranthus hypochondriacus, amaranth (a ...200717151909
host-plant selectivity of rhizobacteria in a crop/weed model system.belowground microorganisms are known to influence plants' performance by altering the soil environment. plant pathogens such as cyanide-producing strains of the rhizobacterium pseudomonas may show strong host-plant selectivity. we analyzed interactions between different host plants and pseudomonas strains and tested if these can be linked to the cyanide sensitivity of host plants, the cyanide production of bacterial strains or the plant identity from which strains had been isolated. eight strain ...200717786217
weed growth inhibitors from aspergillus fischeri tistr 3272.chloroform and ethyl acetate extracts of aspergillus fischeri tistr 3272 showed good growth inhibitory activity on mimosa pigra and echinochloa crus-galli. bioassay-directed fractionation of the active extracts led to the isolation of five known compounds, (+)-terrein (1), (-)-6-hydroxymellein (2), two diketopiperazines (cyclo-(s-pro-s-leu) (3) and cyclo-(s-pro-s-val) (4)) and butyrolactone i (5). compounds 2-5 were reported for the first time in this fungus. their structural determinations were ...200718075891
accumulation of cd, pb and zn by 19 wetland plant species in constructed wetland.uptake and distribution of cd, pb and zn by 19 wetland plant species were investigated with experiments in small-scale plot constructed wetlands, into which artificial wastewater dosed with cd, pb and zn at concentrations of 0.5, 2.0 and 5.0mgl(-1) was irrigated. the results showed that the removal efficiency of cd, pb and zn from the wastewater were more than 90%. generally, there were tens differences among the 19 plant species in the concentrations and quantity accumulations of the heavy meta ...200717353090
phytoremediation of soil co-contaminated with heavy metals and tnt using four plant species.we investigated the germination, growth rates and uptake of contaminants of four plant species, barnyard grass (echinochloa crusgalli), sunflower (helianthus annuus), indian mallow (abutilon avicennae) and indian jointvetch (aeschynomene indica), grown in soil contaminated with cadmium (cd), lead (pb) and 2,4,6-trinitrotoluene (tnt). these contaminants are typically found at shooting ranges. experiments were carried out over 180 days using both single plant cultures and cultures containing an eq ...200717990167
synthesis and herbicidal activity of novel pyrazolo[3,4-d]pyrimidin-4-one derivatives containing aryloxyphenoxypropionate moieties.the 6-(4-alkoxycarbonylalkoxy)phenoxy-3-alkylthio(alkylsulfonyl)-1-phenyl-5-(substituted phenyl)pyrazolo[3,4-d]pyrimidin-4-ones 6 and 7 have been synthesized via the tandem aza-wittig and annulation reactions of the corresponding iminophosphoranes 4, aromatic isocyanates, and substituted phenols 2 in 52-98% yields. their structures were clearly verified by spectroscopic data (ir, (1)h nmr, (13)c nmr, ms, and elemental analysis or x-ray diffraction crystallography). and the results of preliminary ...200717337186
design, synthesis, and quantitative structure-activity relationship study of herbicidal analogues of pyrazolo[5,1-d][1,2,3,5]tetrazin-4(3h)ones.a series of pyrazolo[5,1-d][1,2,3,5]tetrazin-4(3h)one derivatives were designed, synthesized, and evaluated for their herbicidal activities where some of these compounds provided >80% control of brassica campestris at 10 microg/ml. quantitative structure-activity relationship studies were performed on these compounds using physicochemical parameters (electronic, verloop, or hydrophobic) as independent parameters and herbicidal activity as a dependent parameter, where herbicidal activity correlat ...200717300154
[regulation effects of arbuscular mycorrhizal fungi on the interactions between barnyard grass and upland rice under enhanced nitrogen supply].a pot experiment was conducted to study the regulation effects of arbuscular mycorrhizal fungi (amf) on the interactions between echinochloa crus-galli var. mitis l. and oryza sativa l. under enhanced n supply (4.0 g n x m(-2) x a(-1)). the results showed that under monoculture condition, the amf colonization on e. crus-galli increased but that on o. sativa decreased. in the treatments with and without amf inoculation, upland rice biomass and its p and n uptake increased by 42.35% and 13.48%, 4. ...200718163320
mechanism of selective phytotoxicity of l-3,4-dihydroxyphenylalanine (l-dopa) in barnyardgrass and lettuce.l-3,4-dihydroxyphenylalanine (l-dopa) is one of the few allelochemicals in which the phytotoxic action mechanism has been studied. excess exogenous l-dopa suppresses root elongation in some plant species, and the inhibitory action is species-selective. the main factor of phytotoxicity of l-dopa is considered to be oxidative damage by reactive oxygen species (ros) and/or free radical species (frs). this study was performed to elucidate the mechanism of species-selective phytotoxicity. the involve ...200717899281
rice allelopathy induced by methyl jasmonate and methyl salicylate.methyl jasmonate (meja) and methyl salicylate (mesa) are important signaling molecules that induce plant defense against insect herbivores and microbial pathogens. we tested the hypothesis that allelopathy is an inducible defense mechanism, and that the ja and sa signaling pathways may activate allelochemicals release. exogenous application of meja and mesa to rice (oryza sativa l.) enhanced rice allelopathic potential and led to accumulation of phenolics, an increase in enzymatic activities, an ...200717415624
wild plants, andropogon virginicus l. and miscanthus sinensis anders, are tolerant to multiple stresses including aluminum, heavy metals and oxidative stresses.to isolate high-tolerant plants against aluminum (al), heavy metals and/or oxidative stresses as a final goal, screening of al tolerant plants from a collection of 49 wild plants was first of all performed in this study. andropogon virginicus l. and miscanthus sinensis anders showed high al tolerant phenotypes (more than 35% values in both relative root growth and germination frequency even under 900 microm al concentration) in our screening. al tolerance mechanisms in these two plants were char ...200818204843
pyrimidinyl-substituted amides and thioureas: syntheses, crystal structure and herbicidal activities.the high herbicidal activities of [1,2,4]triazolo[1,5-c]pyrimidine and 2h-1,2,4-thiadiazolo[2,3-a]pyrimidine derivatives suggested the development of new fused heterocyclic compounds for application as herbicides.200818080290
seed defensins of barnyard grass echinochloa crusgalli (l.) beauv.from the annual weed barnyard grass echinochloa crusgalli (l.) beauv., two novel defensins ec-amp-d1 and ec-amp-d2 that differ by a single amino acid substitution were isolated by a combination of different chromatographic procedures. both defensins were active against several phytopathogenic fungi and the oomycete phytophthora infestans at micromolar concentrations. the ec-amp-d1 showed higher activity against the oomycete than ec-amp-d2. the comparison of the amino acid sequences of the antifu ...200818625284
phytotoxic activity and conformational analysis of thymol analogs from hofmeisteria schaffneri.bioassay-guided fractionation of two phytotoxic extracts (a ch(2)cl(2)-meoh (1:1) and an aqueous) prepared from the aerial parts of hofmeisteria schaffneri led to isolation of thymol analogs 3-5, along with seven known compounds, 1, 2 and 6-10. compounds 3-5 were identified by spectroscopic methods as 1,4-bis(2'-hydroxy-4'-methylphenyl)butane-1,4-dione (3), 2-isopropyl-5-methylphenyl (2z)-2-methylbut-2-enoate (4) and 2-hydroxy-2-(2-hydroxy-4-methylphenyl)propane-1,3-diyl (2z,2'z)bis(2-methylbut- ...200818328513
population structure of fusarium fujikuroi from california rice and water grass.the recent observance of fusarium fujikuroi, the causal agent of bakanae disease of rice, in california provides a unique opportunity to assess the population diversity of an introduced pathogen in a new environment. we collected 172 isolates of this pathogen between 2000 and 2003 from california rice and two from water grass (echinochloa spp.). pathogenicity of f. fujikuroi was demonstrated on early water grass (e. oryzoides) and barnyard grass (e. crus-galli) indicating that weed control shoul ...200818943737
[changes of microbial biomass carbon and enzyme activities in rice-barnyard grass coexisted soils].taking barnyard grass (echinochloa crus-galli), allelopathic rice (oryza sativa) pi312777, and non-allelopathic rice liaojing-9 as test materials, this paper studied the changes of microbial biomass c and of dehydrogenase, urease and invertase activities in soils under 1 : 1 rice-barnyard grass coexistence. the results showed that with the coexistence of barnyard grass, the microbial biomass c in rhizosphere soil of pi312777 was decreased by 50.52% (p < 0.01), while that in inter-row soil was in ...200819123361
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