Publications

parasites and flower choice of bumblebees.	in a field experiment, we tested whether workers of bumblebees, bombus pascuorum and b. humilis, parasitized by larvae of conopid flies, physocephala rufipes and sicus ferrugineus, differ in their flower choice from unparasitized ones. we collected workers at random in the field and immediately tested them in experimental arenas that offered the choice of a reference plant (red clover, trifolium pratense) versus a test plant (from five species). the choices of 396 workers were analysed with logi ...	1998	9632470
effects of elevated co2 on flowering phenology and nectar production of nectar plants important for butterflies of calcareous grasslands.	effects of elevated co2 on flowering phenology and nectar production were investigated in trifolium pratense, lotus corniculatus, scabiosa columbaria, centaurea jacea and betonica officinalis, which are all important nectar plants for butterflies. in glasshouse experiments, juvenile plants were exposed to ambient (350 μl l(-1)) and elevated (660 μl l(-1)) co2 concentrations for 60-80 days. elevated co2 significantly enhanced the development of flower buds in c. jacea. b. officinalis flowered ear ...	1998	28307818
performance of lactating dairy cows fed red clover or alfalfa silage.	the objective of this study was to compare utilization of red clover (trifolium pratense l.) and alfalfa (medicago sativa l.) by lactating dairy cows. red clover and alfalfa were harvested and conserved as silage at two maturities in 2 consecutive yr. each year, diets containing experimental forages and supplemental grain were fed to 16 multiparous holstein cows in early lactation in a replicated 4 x 4 latin square lactation trial. lactation performance and nutrient intake responses caused by fo ...	1997	9436113
forage systems for beef production from conception to slaughter: iii. finishing systems.	fall-weaned angus calves grazed or were fed different forages during winter followed by 1) n-fertilized tall fescue (festuca arundinacea schreb.) grazed alone, 2) bluegrass (poa pratensis l.)-white clover (trifolium repens l.) sequence grazed with tall fescue-red clover (trifolium pratense l.), or 3) bluegrass-white clover sequence grazed with alfalfa (medicago sativa l.)-orchardgrass (dactylis glomerata l.). heifers were supplemented with grain at 1% of bw from april until slaughter in july. on ...	1996	8707721
investigation of the use of honey bees and honey bee products to assess heavy metals contamination.	experiment was carried out using 12 colonies of honey bees bred in hives located near an extraurban crossroad. we analyzed the pb, cd and zn deposited on the bee's surfaces and the heavy metal accumulation in the foragers, dead bees, honey products and some environmental markers during nine weeks of the experiment. results showed a large amount of zn and cd on the bee's surface as a consequence of atmospheric fallout, whereas pb seems to be either water-extractable and/or likely accumulated in t ...	1996	24193729
floral constancy in bumble bees: handling efficiency or perceptual conditioning?	individual bees often prefer flowers of the same species that they are already foraging on, and other individual bees prefer other flowers. this "floral constancy" has classically been explained as a learned behavior by which bees avoid wasting time switching between handling techniques. choice trails were given to bombus vagans workers that were freely foraging in mixed and pure fields of trifolium pratense, t. repens, viccia cracca, and prunella vulgaris. contrary to expectation, (1) bees show ...	1996	28307449
the in vitro biosynthesis of the exopolysaccharide produced by rhizobium leguminosarum bv. trifolii, strain na 30.	rhizobium leguminosarum bv. trifolii, strain na 30 nodulates both red (trifolium pratense) and white (t. repens) clover and produces an acidic exopolysaccharide (eps) containing glucose, galactose, glucuronic acid, acetate and ketalpyruvate residues in a 5:1:2:1:2 molar ratio. the in vitro synthesis of this eps as well as the characterization of five structurally related lipid linked oligosaccharides is described employing edta treated cells as enzyme preparation and 14c-labelled udp-glc, udp-gl ...	1996	8832106
a hierarchical analysis of population genetic structure in rhizobium leguminosarum bv. trifolii.	little is known about the population processes that shape the genetic diversity in natural populations of rhizobia. a sample of 912 rhizobium leguminosarum biovar trifolii isolates were collected from naturalized red clover populations (trifolium pratense) and analysed for 15 allozyme loci to determine the levels and distribution of genetic diversity. hierarchical analyses compared different sampling levels, geographical separation, and temporal separation. total genetic diversity across all iso ...	1996	8673267
a central domain of rhizobium node protein mediates host specificity by determining the hydrophobicity of fatty acyl moieties of nodulation factors.	previously, we have shown that the node gene is a major determinant of the difference in host range between rhizobium leguminosarum biovars viciae and trifolii. a new genetic test system for stringent functional analysis of node genes was constructed. by testing chimeric node genes constructed by the exchange of polymerase chain reaction (pcr)-generated restriction cassettes, we show that a central domain, containing only 44 non-conserved amino acid residues, determines the host specificity of t ...	1995	8577248
evaluation of brassicas in grazing systems for sheep: i. quality of forage and animal performance.	four years of grazing trials were conducted with brassica forages to evaluate their chemical composition and effect on adg of fattening lambs and breeding ewes in late fall. brassicas tested included kales (brassica oleracea l. var. acephala dc), turnips (b. rapa l.), and a chinese cabbage hybrid (b. rapa l. x b. pekinensis [lour.] rupr.). daily gains of lambs varied widely among years (19 to 330 g/d); adg on brassicas were, however, generally higher than on stockpiled kentucky 31 tall fescue (f ...	1994	7928762
oviposition and development of face flies in dung from cattle on herbage and supplemented herbage diets.	dung was collected from angus cattle (bos taurus l.) fed (ad libitum) hays of endophyte-free (ef) and endophyte (acremonium coenophialum morgan-jones and gams) infected (ei) tall fescue (festuca arundinacea schreb.), smooth bromegrass (bromus inermis leyss.), red clover (trifolium pratense l.), alfalfa (medicago sativa l.), and alfalfa-smooth bromegrass (1:1 w/w) and green-chopped kentucky bluegrass (poa pratensis l.). samples of dung were subsequently collected from the same animals offered the ...	1994	7886909
distribution in the western united states on alfalfa and cultivar reaction to mixed populations of ditylenchus dipsaci and aphelenchoides ritzemabosi.	ditylenchus dipsaci and aphelenchoides ritzemabosi were extracted from 29 of 40 plant samples (72.5%) collected from arizona, california, colorado, idaho, montana, oregon, south dakota, utah, washington, and wyoming. percentages of a. ritzemabosi in tissue of the 29 samples ranged from 1.77 to 67.82%. only ditylenchus dipsaci was recovered from the remaining 11 samples. all of the 16 fields sampled in wyoming contained both nematodes. percentages of a. ritzemabosi in the wyoming samples ranged f ...	1994	19279952
a soap technique for cell separation to study the seed coat of sesbania punicea.	a technique is described for separating plant cells used for morphological studies. the plant material is placed in a concentrated solution of olive oil castile soap for 1-2 days or more. the material is then thoroughly washed and placed between two glass slides. the upper glass slide is lifted from the lower one, then gently pressed down several times. through this procedure malpighian cells of the seed coat of sesbania punicea, mesophyll cells of euphorbia peplus and of trifolium pratense and ...	1993	7687883
forage systems for beef production from conception to slaughter: ii. stocker systems.	fall weaned angus calves grazed stockpiled 1) tall fescue (festuca arundinacea schreb.), 2) tall fescue-red clover (trifolium pratense l.), or 3) tall fescue-alfalfa (medicago sativa l.) or were barn-fed, 4) tall fescue hay, 5) orchardgrass (dactylis glomerata l.)-alfalfa hay, or 6) tall fescue silage from late october to early april during each of 5 yr. infection of the fescue with acremonium coenophialum ranged from 0 to 55%. there were two replications each of steers and heifers for each fora ...	1992	1312526
forage systems for beef production from conception to slaughter: i. cow-calf production.	six year-round, all-forage, three-paddock systems for beef cow-calf production were used to produce five calf crops during a 6-yr period. forages grazed by cows during spring, summer, and early fall consisted of one paddock of 1) tall fescue (festuca arundinacea schreb.)-ladino clover (trifolium repens l.) or 2) kentucky blue-grass (poa pratensis l.)-white clover (trifolium repens l.). each of these forage mixtures was combined in a factorial arrangement with two paddocks of either 1) fescue-red ...	1992	1548221
monensin controlled-release intraruminal capsule for control of bloat in pastured dairy cows.	monensin, a polyether ionophore antibiotic, is potentially an important agent for bloat relief in dairy cows grazing temperate legume-based pasture. a series of studies was undertaken to determine the effect of monensin, when delivered continuously in the rumen of lactating dairy cows by means of controlled-release capsules (monensin crc). such devices release approximately 300 mg/head/day for 100 d. a short-term pilot study made at ruakura, new zealand, tested monensin crc in cows selected for ...	1991	2018451
effects of synthetic and naturally occurring flavonoids on benzo[a]pyrene metabolism by hepatic microsomes prepared from rats treated with cytochrome p-450 inducers.	activity-directed fractionation of trifolium pratense resulted in isolation of the isoflavone biochanin a, a potent inhibitor of metabolic activation of the carcinogen benzo[a]pyrene (b[a]p) in cells in culture. to determine the structural features required for maximal inhibition of cytochrome p-450 mediated metabolism of b[a]p, the inhibitory potencies of 23 flavonoids on metabolism of b[a]p to water-soluble derivatives were examined in liver s-9 homogenate from rats induced with aroclor 1254. ...	1991	1913623
monitoring by epifluorescence microscopy of organelle dna fate during pollen development in five angiosperm species.	the fates of mitochondrial and plastid nucleoids during pollen development in six angiosperm species (antirrhinum majus, glycine max, medicago sativa, nicotiana tabacum, pisum sativum, and trifolium pratense) were examined using epifluorescence microscopy after double staining with 4',6-diamidino-2- phenylindole (dapi) to stain dna and with a potentiometric dye (either dioc7 or rhodamine 123) for visualization of metabolically active mitochondria. from the pollen mother cell stage to the microsp ...	1991	1879613
in vitro selection for 2,4-d tolerance in red clover.	in vitro, selection is a viable method of selecting herbicide-tolerant crops. this research was to evaluate in vitro selection techniques for enhancing 2,4-d [(2,4-dichlorophenoxy) acetic acid] tolerance in red clover (trifolium pratense l.). in vivo and in vitro responses to 2,4-d of eight diverse red clover populations were correlated (r=0.77), justifying in vitro selection for 2,4-d tolerance. suspension cultures of a red clover genotype capable of regeneration were plated onto agar-based nut ...	1989	24227154
rhizobium leguminosarum genes required for expression and transfer of host specific nodulation.	the contributions of various nod genes from rhizobium leguminosarum biovar viceae to host-specific nodulation have been assessed by transferring specific genes and groups of genes to r. leguminosarum bv. trifolii and testing the levels of nodulation on pisum sativum (peas) and vicia hirsuta. many of the nod genes are important in determination of host-specificity; the node gene plays a key (but not essential) role and the efficiency of transfer of host specific nodulation increased with addition ...	1989	24272714
creep grazing and early weaning effects on cow and calf productivity.	one hundred fifty simmental-hereford cows and calves were used in a 3-yr study to evaluate three creep grazing treatments and an early weaning treatment on cow and calf performance during midsummer (july to september). calves were approximately 150 d of age and averaged 178.6 kg when treatments were initiated. tifleaf pearl millet (pennisetum americanum l. leeke) was used as the forage for two of the creep treatments, representing two cow stocking intensities of .466 (tlm1) and .239 (tlm2) ha of ...	1988	3397337
cryptic viruses in hop trefoil (medicago lupulina) and their relationships to other cryptic viruses in legumes.	three double-stranded (ds) rna-containing viruses, named hop trefoil cryptic virus (htcv) 1, 2 and 3, were found in apparently healthy seedlings of hop trefoil (medicago lupulina). only 1-2% of plants tested were virus-free. the particles occurred in the cytoplasm, nuclei and nucleoli of parenchyma cells. they were purified as a mixture (htcv-m) with a mean yield of 50-100 micrograms/kg fresh tissue, and an antiserum was obtained. htcv1 was serologically related to one component (acv1) of a mixt ...	1987	3450677
clonal propagation of trifolium pratense, t. resupinatum and t. subterraneum by direct somatic embryogenesis on cultured immature embryos.	direct somatic embryogenesis on immature zygotic embryos in vitro has been confirmed for trifolium pratense and extended to t. resupinatum and t. subterraneum. for all species direct embryo cloning can be achieved on an appropriate basal medium supplemented with 1gl(-1) yeast extract and 0.05 mgl(-1) bap. basal medium/sucrose formulation, level of yeast extract and level of bap affected the nature of in vitro responses. in particular, for t. pratense and t. subterraneum lowering of the yeast ext ...	1986	24248123
associative nitrogen fixation by klebsiella spp.: adhesion sites and inoculation effects on grass roots.	adhesion sites on grass roots for klebsiella strains carrying type 3 or type 1 fimbriae or both were determined. adhesion of the strains to the roots of poa pratensis and festuca rubra was highly localized; the bacteria adhered strongly to root hairs and with a markedly lower efficiency to the surface of the zone of elongation and to the root cap mucilage. no adhesion to the epidermal cells between root hairs was observed. the adhesion sites were identical for the type 3- and 1-fimbriated bacter ...	1986	16347205
the role of condensed tannins in the nutritional value of lotus pedunculatus for sheep. 5. effects on the endocrine system and on adipose tissue metabolism.	1. three experiments were conducted using lotus pedunculatus containing high concentrations of condensed tannins (ct), and utilizing the principle that polyethylene glycol (peg) application (molecular weight 3350) will irreversibly bind a portion of the ct and thus reduce the dietary reactive (i.e. non-peg bound) ct concentration. lotus diets containing 95, 45 and 14 g total reactive ct/kg dry matter (dm), induced by spraying with three peg rates, were given to sheep at hourly intervals (600 g d ...	1986	3676235
the role of condensed tannins in the nutritional value of lotus pedunculatus for sheep. rates of body and wool growth.	lotus pedunculatus (cv. grasslands maku) grown on acid low-fertility soil and containing high concentrations of condensed tannin (76-90 g/kg dry matter (dm] was grazed by growing sheep for 31-42 d periods in three experiments. in expt 2 an additional group of lambs grazed areas oversown with white clover (trifolium repens) and red clover (trifolium pratense). lambs were transferred from grazing ryegrass (lolium perenne)-white clover straight on to lotus in all experiments (unconditioned sheep). ...	1985	4063306
transfer of rhizobium meliloti psym genes into agrobacterium tumefaciens: host-specific nodulation by atypical infection.	the psym megaplasmid of rhizobium meliloti 2011 mobilized by plasmid rp4, or plasmid pgmi42, an rp4-prime derivative which carries a 290-kilobase psym fragment including nitrogenase and nod genes, was introduced into agrobacterium tumefaciens. the resulting transconjugants induced root deformations specifically on the homologous hosts medicago sativa and melilotus alba and not on the heterologous hosts trifolium pratense and trifolium repens. the root deformations were shown to be genuine nodule ...	1984	6690420
competitiveness of rhizobium trifolii strains associated with red clover (trifolium pratense l.) in mississippi soils.	five strains of rhizobium trifolii were evaluated in competition with indigenous populations in nodulating red clover (trifolium pratense l.) cv. kenland in two different soils in mississippi. double antibiotic resistance acquisition was used to measure the proportion of nodules occupied by the introduced mutant strains. in vertisol soil, strains rp113-7, 162bb1, lm1, and 162p17 were recovered in at least 94% of the assayed nodules, whereas ta1 was found in 83.8% of the nodules. at an ultisol lo ...	1982	16346130
allelopathic properties of α-terthienyl and phenylheptatriyne, naturally occurring compounds from species of asteraceae.	alpha-terthienyl (α-t), a naturally occurring polyacetylene derivative from roots oftagetes erecta l., and phenylheptatriyne (pht), from leaves ofbidens pilosa l., were tested as possible allelopathic agents against four seedling species (asclepias syriaca l.,chenopodium album l.,phleum pratense l.,trifolium pratense l.).asclepias was the most sensitive of the species. allelopathic activity was enhanced in the presence of sunlight or sources of near-uv, with lc50s fora. syriaca of 0.15 ppm and 0 ...	1982	24415251
n abundance of nodules as an indicator of n metabolism in n(2)-fixing plants.	this paper expands upon previous reports of (15)n elevation in nodules (compared to other tissues) of n(2)-fixing plants. n(2)-fixing nodules of glycine max (soybeans), vigna unguiculata (cowpea), phaseolus vulgaris (common bean), phaseolus coccineus (scarlet runner bean), prosopis glandulosa (mesquite), and olneya tesota (desert ironwood) were enriched in (15)n. nodules of vicia faba (fava beans), arachis hypogaea (peanut), trifolium pratense (red clover), pisum sativum (pea), lathyrus sativus ...	1982	16662517
isotopic fractionation associated with symbiotic n(2) fixation and uptake of no(3) by plants.	isotopic fractionation associated with n(2) fixation and no(3) (-) uptake by plants are relevant to the accuracy of estimates of n(2) fixation based on differences in the natural abundance of (15)n between n(2) fixing and nonfixing plants. the isotope effect on n(2) fixation by soybeans (glycine max [l] merrill, variety harosoy) and red clover (trifolium pratense [l]) was determined from the difference in (15)n abundance between atmospheric n(2) and the total n of plants grown hydroponically wit ...	1980	16661392
in vitro digestion of bloat-safe and bloat-causing legumes by rumen microorganisms: gas and foam production.	leaves of three bloat-safe legumes -- birdsfoot trefoil (lotus corniculatus l.), sainfoin (onobrychis viciaefolia scop.), and cicer milkvetch (astralagus cicer l.) -- and of three bloat-causing legumes -- alfalfa (medicago sativa l.), red clover (trifolium pratense l.), and white clover (trifolium repens l.) -- were incubated with strained rumen fluid or with mixed rumen fluid and solids. gas released was measured during the early period (0 to 22 h) of this in vitro digestion. gas volume was gre ...	1980	7419778
[biological fertilization (mycorrhiza + rhizobium + phosphobacteria) of trifolium pratense in different cultural conditions].		1979	293006
microbial changes in clover rhizosphere after foliar and soil application of cobalt.	application of cobalt(ii) nitrate to the leaves of red clover (trifolium pratense l.) resulted in a pronounced increase of dry weight and the number of root nodules. counts of bacteria in the rhizosphere, content of ammonia and production of carbon dioxide in rhizosphere soil were also higher, whereas the content of nitrates decreased. differences in the counts of bacteria, actinomycetes, azotobacter, anaerobic bacteria and cellulose decomposing bacteria in the rhizosphere of control and treated ...	1978	669491
effects of potassium fertilization and pratylenchus penetrans on yield and potassium content of red clover and alfalfa.	red clover and alfalfa were inoculated with pratylenchus penetrans and grown in an alberry sandy loam soil to which potassium (k) was added at seeding at 0, 41.5, 83, and 166 microg/g. in one experiment with alfalfa, additional k was added after each forage cut to replace that which was removed. nematode populations were not consistently affected by k fertilization. nematode infection stunted red clover and alfalfa and resulted in lower yields at all k levels, except for alfalfa at the lowest k ...	1976	19308208
effect of meloidogyne incognita on reproduction of pratylenchus penetrans in red clover and alfalfa.	roots of seedlings of red clover and alfalfa growing on 10(1) hoagland and arnon solution agar were inoculated with various combinations of meloidogyne incognita and pratylenchus penetrans. egg-laying by p. penetrans decreased as the number of nematodes, the ratio of entrant m. incognita to entrant p. penetrans, and the priority of invasion of roots by m. incognita increased. embryogeny and hatching of eggs of p. penetrans, and development of larvae of m. incognita, were not affected. in red clo ...	1975	19308128
[sodium, zinc and managanese available to dairy cows grazing on weathered soils of different geological origins, as determined by analysis of the black hairs of the cattle, and of hops and purple clover].		1971	5556570
formation of tumor-like structures on legume roots by rhizobium.	tumor-like structures appeared on the roots of medicago sativa, alysicarpus vaginalis, and trifolium pratense inoculated with a non-nodulating strain of rhizobium trifolii or with irradiated cultures of either of two nodulating rhizobium strains. the structures were composed of disorganized plant tissues which, on the basis of microscopic examination, were devoid of bacterial cells. rhizobia which could nodulate legumes of one cross-inoculation group and which were able to induce formation of su ...	1971	4995381
electron microscopy of the development of erysiphe polygoni in resistant and susceptible trifolium pratense.		1969	5377739
enzymes of the glyoxylate cycle in rhizobia and nodules of legumes.	the relatively high level of fatty acids in soybean nodules and rhizobia from soybean nodules suggested that the glyoxylate cycle might have a role in nodule metabolism. several species of rhizobia in pure culture were found to have malate synthetase activity when grown on a number of different carbon sources. significant isocitrate lyase activity was induced when oleate, which presumably may act as an acetyl coa precursor, was utilized as the principle carbon source. malate synthetase was activ ...	1966	16656404
[actions of various antibiotics on symbiosis of the red clover (trifolium pratense l.)].		1963	14048729
reproductive disturbances of romney ewe lambs grazed on red clover (trifolium pratense) pastures.		1958	13590269