bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of glyphosate on uptake and translocation of calcium ion in soybean seedlings
Authors: DUKE S. O. , WAUCHOPE R. D. , HOAGLAND R. E. , WILLS G. D. 
Published: July 2006

SummaryCalcium ion in hydroponic solution with glyphosate [N‐phosphonomethyl (glycine)] did not significantly influence the efficacy of the herbicide in reducing growth of soybean (Glycine max) seedlings. Data from atomic absorption spectroscopy studies revealed that glyphosate reduced Ca2+ uptake and translocation, whether supplied alone or with other metal ions. Results with radiolabelled 45Ca2+ indicated that glyphosate severely retards translocation of Ca2+ from the roots to the leaves and cotyledons but the effect is not detectable until 24 h after exposure to glyphosate.Influence du glyphosate sur l'absorption el le mourement de I'ion calcium dans des plantules de soja.L'ion calcium présent dans une solution hydroponique contenant du glyphosate (N‐phosphono‐methyl (glycine) ne modifie pas dc facon significative I'efficacité de I'herbicide dans son action sur la réduction de croissance de plantules de soya. Des données fournies par la spectroscopie d'absorption atomique montrent que le glyphosate reduit l'absorption et le mouvement des ions Ca2+ seuls ou en présence d'ionsd'autresmétaux. Les résultats obtenus avec des ions marqués 45Ca2+ révèlent que le glyphosate retarde notablement le mouvement des ions Ca2+ entre les racines et les feuilles ou les cotylédons mais cet effct n'est pas détectable avant une péríode de 24h suivant l'exposition au glyphosate.
Biological activity of dinitramine in soils
Authors: OKAFOR L.I. , SAGAR G.R. , SHORROCKS V.M. 
Published: July 2006

SummaryIn pot studies with dinitramine the susceptibility of French bean (Pltaseolus vulgaris L.) seedlings to the herbicide was influenced by the depth of sowing the seed and the dose and depth of incorporation of the herbicide.Maximum phytotoxicity occurred when the seeds of French bean were sown into a zone in which dinitramine had been incorporated. Where the seeds were separated from the herbicidetreated zone by a layer of untreated soil, the susceptibility of the French bean seedlings increased with increasing depth of sowing. The greater the distance between the point of contact with the herbicide and the soil surface the greater was the injury.Dinitramine is active in the vapour phase, and volatilization and bioactivity were directly related to concentration and inversely related to depth of incorporation and of placement in the soil.
Einfluss von Pflanzenschutzmitteln einer Zuckerrüben‐Spritzfolge auf biologische Aktivitäben und auf den Abbau von Chloridazon im Boden. I. Freilandversuche
Authors: PESTEMER W. , MALKOMES H.‐P. 
Published: July 2006

ZusammenfassungIn mehrjährigen Feldversuchen wurde der Einfluss von Chloridazon (Pyramin) — allein und in Kombination mit anderen Pflanzenschutzmitteln einer Zuckerrüben‐Spritzfolge — an drei Standorten mit ähnlichen Boden‐ und Klimabedingungen auf verschiedene bodenbiologisch Aktivitäten (Dehydrogenaseaktivität, Strohabbau) sowie die Abbaubarkeit und Pflanzenverfügbarkeit von Chloridazon im Boden untersucht.Nach einer anfänglichen lag‐Phase verlief der Abbau von Chloridazon sehr schnell und zeigte in den untersuchten Jahern eine 50%ige Abnahme der Ausgangskonzentration in 18 bis 53 Tagen. Die prozentuale Pflanzenverfügbarketi des Wirkstoffs im Verchältnis zum Gesamtrückstand ging innerhalb von 36 Tagen nach der Applikation von etwa 30% auf etwa 2% zurück. Durch die Präparate der Spritzfolg wurde keine Änderung der Peristenz des Wirkstoffs im Boden herbeigefübrt.Während die Dehydrogenaseaktivität durch Pyramin allein kaum gehemmt wurde, trat in der Spritzfolge von allem in der obsten Bodenschicht (0–5 cm) in eingen Fällen bis zur Erntezeit eine Hemmung gegenüber der Kontrolle und besonders gegenüber der Behandlung mit Pyramin allein auf. Der Strohabbau wurde nicht beeinflust.Weder zwischen den Gesamtrückständen an Chloridazon noch deren wasserextrahierbarem Anteil bestanden Korrelationen zu den untersuchten bodenbiologischen Aktivitäten.
Seasonal variation in the emergence of annual weeds — an introductory investigation in Sweden
Authors: HÅKANSSON SIGURD 
Published: July 2006

SummarySeeds of thirteen annual weed species were collected in early autumn. Within a few weeks they were incorporated in soil. They were stored either in the field or in climate chambers where seasonal variations in field soil temperature were simulated. Seedling emergence under various conditions was determined at different times, within a period of 1 or 2 years after the incorporation of seeds in soil. Some material was transferred from the storage places at different times of year and placed in cabinets with standardized temperature regimes for 3‐week emergence tests. These showed increased emergence during late autumn and winter and a maximum at some time in winter in both summer and winter annuals. Some winter annuals showed a second maximum in late summer. Counts of seedlings in the storage places, in unstirred soil, showed maximum emergence in spring for both winter and summer annuals — or in summer for Spergula arvensis and, possibly, Capsella bursa‐pastoris. In certain treatments in the field, the soil was stirred once, on different dates, simulating tillage at different limes of year. The emergence following stirring of the soil was greatest in spring for the summer annuals, except for Spergula arvensis, which showed more emergence from early to mid summer. Several winter annuals showed an emergence peak after stirring in late summer or early autumn.Variations saisonnières dans la levèe des mauvaises herbes annuelles‐étude préliminaire en Suède
Timing of seedling emergence and reproduction in some tropical dicotyledonous weeds
Authors: MARKS M.K. 
Published: July 2006

SummaryThe periodicities of seedling emergence of seventeen dicotyledonous weeds were determined and fourteen of these examined in detail. In addition, the periodicity of vegetative growth and reproductive development was recorded for all dicotyledonous species in the study area.Field emergence at monthly intervals during one year was compared with the emergence of seedlings from soil transferred to a shade house and kept moist. This comparison suggested that lack of water during the dry season was the dominant factor controlling germination, although several species failed to germinate when given adequate water under shade‐house conditions indicating that innate or induced dormancy also occurred.Species were separated into two groups based on the liming and duration of their main phenological stages. The first group contained species which had individuals present throughout the year while plants in the second group died during the dry season and reappeared at the start of the wet season. Most species in the former had some individuals flowering or shedding seed all year round while the latter had a short period of vegetative growth followed by prolonged reproduction.The possibility of using emergence and phenological data for improving tropical weed control is discussed.
A decade of weed research in the Indo‐Canadian Dryland Project
Authors: FRIESEN G. H. , KORWAR G. R. 
Published: July 2006

SummaryWeed research within the All India Co‐ordinated Research Project for Dryland Agriculture over the past decade has included weed surveys to determine the dominant weed flora in various regions and cropping systems of the country: weed interference studies to determine the losses caused by weeds in various crops, weed control studies involving traditional and improved tillage methods: chemical control of weeds with emphasis on herbicides available in India, and studies of integrated weed‐management systems. Much useful information has been accumulated and improved weed‐control practices have been developed. The strategies for weed‐control research and technology transfer discussed in this paper may be helpful in developing or introducing improved weed control practices in other Third‐World countries.
Etude du stock en semences d'Echinochloa crus‐galli (L.) Beauv. dans le sol des rizières du Gharb (Maroc)
Authors: BOUHACHE M. , BOULET C. , HAMMOUMI M. 
Published: July 2006

RésuméDes estimations du nombre de caryopses viables d'E. crus‐galli., ont été effectuées è partir d'échan tillons de sol prélevés dans vingt‐six rizières du Gharb (MAROC). Ces dernières ont été choisies selon trois facteurs de stratification: type de sol, rotation et âge de la rizière. La valeur moyenne du stock de caryopses d'E. crus‐galli est de 1285 caryopses au m2 sur 60 cm de profondeur. Sa contribution moyenne au stock total est de 7.2%. Le plan d'échantillonnage a permis d'analyser l'effet sol pour la rotation — 3 années de riz et 3 annés de culture asséchante et l'effet de la rotation sur sol merja (ce type de sol se caractérise par les stocks les plus faibles en rotation — 3 années de riz et 3 annés de culture asséchante; et en rotation — 3 annés de riz et I année de culture asséchante).Le profil moyen de répartition des caryopses d'E. crus‐galli dans le sol est le suivant: 85%, 12.5% et 2.5% respectivement dans les horizons 0–20, 20–40 et 40–60 cm. Les levées au champ d'E, crus‐galli., de la récolte au semis de la culture suivante, ont représenté 0.65% du stock dans le sol.
Herbaceous vegetation development and weed potential in slash and burn agriculture (Jhum) in N. E. India
Authors: SAXENA K. G. , RAMAKRISHNAN P. S. 
Published: July 2006

SummaryThe patterns of herbaceous vegetation development and weed potential following slash and burn clearing after different lengths of time between the cultivation cycles are described. The early stages of secondary succession following burning tended to conform closely to the ‘initial floristic compositione’ model under shorter cycles of 4 and 6 years between cultivation, but the ‘relay floristicse’ model was found to be more applicable to the cycles of 10 and 20 yearse’ duration. Weed population, in terms of density, biomass and germinable seeds present in the soil, was significantly higher after cycles of 4 and 6 years compared to 10‐ and 20‐year cycles. In all the cycles, however, weed population declined sharply after a year of cropping with an effective weeding programme following the burn.
Sources of viable seed loss in buried dormant and non‐dormant populations of wild oat (Avena fatua L.) seed in Colorado
Authors: ZORNER P. S. , ZIMDAHL R. L. , SCHWEIZER E. E. 
Published: July 2006

SummaryBuried populations of dormant and non‐dormant wild oat (Avena fatua) seed persisted less than 2 years, depth of burial having very little influence on their survival. The mode of seed disappearence, however, was closely related to their depth in the soil. Seed exhaustion through germination in situ increased with increasing depth in the soil, whereas exhaustion through non‐viability increased with decreasing depth. Physical and induced dormancies are apparently not capable of supporting prolonged persistence of A. fatua seeds in soil. The lack of prolonged persistence of A. fatua seeds in Colorado derives from a lack of genetically programmed embryonic dormancy in these populations and makes A. fatua easier to control in Colorado than in other cereal‐growing regions south of the 43rd parallel because it dramatically reduces the survival of seeds in the soil. The most effective non‐chemical control of this grass weed is achieved by means of the shallowest cultivations possible, carried out as late as possible.
Influence of environmental factors on the activity of ioxynil salt and ester applied to Stellaria media
Authors: MERRITT COLIN R. 
Published: July 2006

SummaryExperiments were conducted in a glasshouse and controlled‐environment rooms to investigate the effects of temperature, light, soil moisture and humidity on the activity of ioxynil salt and ester formulations applied to Stellaria media L. Raising the temperature after spraying increased the activity of the ester, whilst changes in humidity had little effect. Activity of the salt was increased by high humidity after spraying, whereas low soil moisture before spraying markedly reduced the susceptibility of S. media to both formulations. When the intensity of natural daylight was varied by shading, the activity of ioxynil ester was greatest where post‐spraying light levels were either very low or very high.Ioxynil activity was consistently greater in the glasshouse than in controlled‐environment rooms. This may be partly due to the wide diurnal fluctuations of temperature and humidity and the occurrence of periods of high light intensity in the glasshouse.
Time of onset of competition and effects of various fractions of an Avena fatua L. population on spring barley
Authors: PETERS N.C.B. 
Published: July 2006

SummaryThe growth and competition of wild oats (Avena fatua L.) emerging at different times, and the time of onset of competition by them were studied using natural populations in spring barley. In one experiment in 1972, wild oats emerging in the 0–0⋅5, 0⋅5–2⋅5, 2⋅5–4 crop leaf stages at densities of 54, 46, 15 m −2 respectively were allowed to compete all season with the crcp. These gave rise to 82, 17 and l% of all seed shed and caused 16%, and two non‐significant yield losses respectively. In two other experiments in 1973, nearly all the wild oats that caused yield losses had emerged by the crop 2˙45 leaf stage. Where wild oats emerging up to the crop 2⋅5 leaf stage were removed, the later ones did not compensate by making extra growth. In one of these experiments in which densities of crop and weed were 416 and 414 m 2, and in the other where they were 295 and 294 m 2 respectively, grain yield losses were significant if the wild oats remained in the crop until the crop had 2⋅5–4⋅5 leaves and 4⋅5–6⋅5 leaves respectively. In a third experiment in 1973 with initial densities of 464 wild oats and 336 barley plants m −2, and where a top dressing of nitrogen was given at the crop 3–4 leaf stage, unlike the other two experiments in 1973 where all nitrogen was applied at sowing, no yield losses resulted unless the wild oats remained in the crop until after the crop 6 leaf stage.
Residualwirkung von Chlortriazin‐Herbiziden im Boden an drei rumänischen Standorten. I. Prognose der Persistenz von Simazin und Atrazin im Boden
Authors: PESTEMER W. , RADULESCU VALERIA , WALKER A. , GHINEA L. 
Published: July 2006

ZusammenfassungAn drei Versuchsstationen in Rumänien, die unterschiedliche Klima‐ und Bodeneigenschaften aufweisen, wurde die Verlustrate von Atrazin und Simazin, die mit jeweils 1 und 3 kg AS ha−1 in Parzellen mit und ohne Mais (Zea mays L.) appliziert wurden, in der oberen 10‐cm‐Schicht analysiert. Unabhängig von Dosierung und Pflanzenbewuchs konnte eine weitgehend vergleichbare 50%ige Konzentrationsabnahme am jeweiligen Standort festgestellt werden, die bei Atrazin zwischen 36 und 68 Tagen und bei Simazin zwischen 48 und 70 Tagen lag.Mit Bodenproben der verschiedenen Standorte wurden weiterhin mit Atrazin Laborversuche durchgeführt, um das Abbauverhalten unter standardisierten Bedingungen und durch Sorptions‐ und Einwaschungsuntersuchungen das Verhalten von Atrazin in diesen Böden zu charakterisieren.Mit Hilfe von Klimadaten für die entsprechende Periode der Freilandversuche und den entsprechenden Konstanten aus den Laborversuchen bzw. aus Literaturdaten wurde mit einem Computerprogramm die Herbizidpersistenz für Feldbedingungen simuliert. Mit dem Modell konnten im Vergleich zu den gemessenen Werten in fast allen Fällen recht gute Übereinstimmungen festgestellt werden, wobei in einigen Fällen das Modell die Tendenz einer geringfügigen Unterschätzung der tatsächlichen Wirkstoffverluste zeigt. Bei der Anwendung des Simulationsmodells ist eine Vorhersage der Persistenz von Atrazin und Simazin auch unter den extremeren Bedingungen der rumänischen Standorte mit ausreichender Genauigkeit für praktische Belange möglich, ohne aufwendige Analysen durchzuführen.
Regeneration of yarrow (Achillea millefolium L.) rhizome fragments of different length from various depths in the soil
Authors: BOURDÔT G. W. 
Published: July 2006

SummaryThe regenerative response of the rhizomes of Achillea millefolium L. to fragmentation and burial was studied in field experiments on three different soils. The percentage of buds producing shoots (estimated from surviving rhizome fragments) from 4 cm (1·6 nodes), 8 cm (3·8 nodes) and 16 cm (6·7 nodes) rhizome fragments was 63, 44 and 32 respectively averaged over all soils and depths of 5, 10 and 15 cm. The depth at which 50% of the fragments failed to produce an emerged shoot (LD50 depth) was 9·3, 12·4 and 17·9 cm for 4‐, 8‐ and 16‐cm fragments respectively averaged over all soils. No fragments survived on the soil surface. The time of emergence of the first shoots was delayed and the rate of emergence and ultimate shoot population reduced with increasing depth of burial. Dry‐matter production by aerial shoots and new rhizomes decreased linearly with depth of burial of the rhizome fragments. Soil type had no effect on the regeneration of the fragments. The significance of the results for the control of A. millefolium is discussed.
Buried seeds in arable soils in Scotland
Authors: WARWICK MONICA A. 
Published: July 2006

Summary:Soil from arable areas in Scotland was examined macroscopically for seeds. In terms of the percentage of sites at which they were recorded, Chenopodium album L. (33%), Poa annua L. (22%), Polygonum aviculare L. (41%), Polygonum persicaria L. (39%), Spergula arvensis L. (42%) and Stellaria media (L.) Vill. (44%) were the most common species found. They accounted for 78% of the seeds recovered. There were eighty different species found over the 5 years of the survey. Estimated total weed populations (m−2) ranged from nil to 170000 with an average of 16000 m−2 in the top 20 cm of soil.
Competitive effects of Avena fatua L. plants derived from seeds of different weights
Authors: PETERS N.C.B. 
Published: July 2006

SummaryA study was made of the caryopsis weights of Avena fatua grown in the field and in pots and of the competitive ability of A. fatua from heavy seed (≥18 mg) and light reed (≤11 mg) grown at a depth of either 25 or 75 mm with spring barley sown at 25 mm.The weight of field‐ and pot‐grown caryopses of A. fatua types fA, fB and fC ranged from 3 to 25, 5 to 23, and 5 to 25 mg respectively. With one exception, both the field‐ and pot‐grown samples showed a double normal distribution pattern. The mean weights of pot‐grown primary and secondary caryopses of fA, fB and fC were 15 and 9, 19 and 11, and 18 and 11 mg respectively.In a competition experiment, A. fatua grown from heavy seeds sown at 75 mm depth with an equal number of barley produced 47% more panicles, 54% more seed and 56% more dry weight per plant than plants from light seeds. When barley and both seed weights of A. fatua were sown at 25 mm depth these differences were smaller, being 21, 28 and 34% respectively.When the barley was at Zadoks stage 87, and when the barley and A. fatua were grown at equal densities at 25 mm depth, the dry weight of barley was reduced from 10·4 to 7·7, and to 5·8 g per plant by light‐ and heavy‐seeded A. fatua, respectively. When the barley was grown at 25 mm and the A. fatua at 75 mm, the weight per barley plant was reduced to 9·5 and 7·2 g by A. fatua plants grown from light and heavy seeds respectively. Reductions in numbers of grain were caused mainly by a reduction in the number of fertile heads.
Basis for changes in glyphosate phytotoxicity to barley by the non‐ionic surfactants Tween 20 and Renex 36*
Authors: O'DONOVAN J. T. , O'SULLIVAN P. A. , CALDWELL C. D. 
Published: July 2006

SummaryThe non‐ionic surfactants, Tween 20 (polyoxy‐ethylene 20 sorbitan monolaurate) and Renex 36 (polyoxyethylene 6‐tridecyl ether) enhanced the retention of a glyphosate‐dye spray solution by barley (Hordeum vulgare L.) leaves. Tween 20 also enhanced absorption of 14C‐glyphosate applied as droplets to barley leaves whereas Renex 36 similarly applied, reduced both absorption and movement of 14C‐glyphosate. Renex 36 alone or mixed with glyphosate increased leakage of electrolytes from barley leaf segments whereas neither Tween 20 nor glyphosate, alone or mixed together, had any effect. No 14C‐glyphosate complexes were detected in mixtures with either surfactant and neither surfactant affected the pH of the glyphosate solution. The results indicate that the reported enhancement of glyphosate phytotoxicity by Tween 20 is due to increased retention and absorption of the herbicide while the reported antagonism caused by Renex 36 is due to reduced glyphosate absorption and movement possibly as a result of alteration of membrane integrity.
Environmental and physiological factors affecting the fate of seeds of yarrow (Achillea millefolium L.) in arable land in New Zealand
Authors: KANNANGARA H. W. , FIELD ROGER J. 
Published: July 2006

SummaryYarrow (Achillea millefolium L.) has arisen as a problem weed in arable land in New Zealand. A spring‐sown yarrow population of 58 plants m−2 produced approximately 243000 seeds. These were capable of immediate germination in the autumn, but virtually no germination occurred in the winter and up to 80–100% at other times of the year. Seeds are positively photoblastic, but a considerable percentage of seed (>30%) may germinate in the dark after chilling, coat pricking, exposure to high nitrate concentrations or to alternating temperatures. Seed buried at 32 cm in undisturbed soil lost viability slowly over 4 years while seed in the top 8 cm lost viability almost completely within 2 years.
A new design for a seed germinator with 100 independently temperature controlled cells
Authors: MCLAUGHLIN N. B. , BOWES G. R. , THOMAS A. G. , DYCK F. B. , LINDSAY T. M. , WISE R. F. 
Published: July 2006

SummaryDesign and performance of a 100‐cell seed germinator capable of simultaneously generating 100 different diurnal temperature cycles with extremes lying between 0 and 45°C is discussed. Each individual cell is equipped with a separate electronic temperature controller employing a thermistor for temperature sensing. The set temperature for each cell is determined by a precision reference resistor in the controller circuit. Six different reference resistors corresponding to six different temperatures are provided for each cell. The reference resistors are mounted on plug‐in modules with one module for each cell. Heating or cooling of the individual cells is provided by thermoelectric heat pumps. Temperature cycling, which approximates a sine function, is achieved by switching the six reference resistors, one at a time, into the controller circuits at appropriate times during a 24h period. Each cell is designed to accept a standard 100 mm Petri dish to contain the seeds. The cells have glass covers to allow entry of light essential for germination of some species.The benefit of using this type of germinator to assess the germination response of Alyssum alyssoides L., Artemisia absinthium L., Euphorbia esula L. and Setaria viridis (L.) Beauv., is discussed. Three dimensional germination response surfaces are given for the four species.
Final distribution is related to rate of spread in alien weeds
Authors: FORCELLA F. 
Published: July 2006

SummaryCurrently important alien weeds that have reached their final distributions are characterized by the high initial rates of spread with which they attained these distributions. Alien weeds, now seemingly unimportant but spreading at high rates, might be tomorrow's noxious weeds. It is suggested that rates of spread of species in a regional alien weed flora that have not yet reached final distributions may be used as indices for identifying future troublesome species. A literature search of several plant ecological attributes revealed that rapid seed germination, especially at low temperatures, may be associated with rapidly spreading weeds.