bluuebunny/crossref_metadata_2025_split huggingface dataset:
A survey of weeds of oilseed rape in central southern England
Authors: FROUD‐WILLIAMS R. J. , CHANCELLOR R. J. 
Published: July 2006

SummaryWeeds in a total of 450 fields of winter oilseed rape in nine areas of central southern England were surveyed, just prior to harvest during summer 1985, to identify those that had survived herbicide treatment or had not been sprayed and, thus, were capable of re‐infestation or contamination of the harvested crop. Sixty‐two species were identified; their levels of infestation were scored and distribution within the field noted. The most frequent species was Galium aparine, which occurred in 57% of fields. Mayweeds (Tripleurospermum inodorum, Matricaria recutita and Anthemis cotula) occurred in 23% of fields and Papaver rhoeas in 21%. All other species occurred in less than 20% of fields, the most prevalent being Sonchus asper(18%). Grassweeds were relatively infrequent, reflecting the widespread use of effective graminicides; the most prevalent was Arena spp., found in 9% of fields. Although most species were distributed throughout the field, Geranium dissection (13%) and Sisymbrium officinale (7%) were virtually confined to field margins (extending 1 m into the crop) and headlands (10m into the crop), respectively. Several species exhibited a well‐defined regional distribution; Silene alba was virtually restricted to the most southern counties surveyed, whilst Papaver rhoeas and Viola arvensis were conspicuously absent from the eastern area.
Population dynamics of Eupatorium adenophorum Spreng. and Eupatorium riparium Regel in relation to burning
Authors: TRIPATHI R. S. , YADAV A. S. 
Published: July 2006

SummaryThe population dynamics of Eupatorium adenophorum Spreng. and E. riparium Regel was studied in the field for 2 years, in relation to burning, by following the fate of individuals in permanent quadrats at short and regular time intervals. Both species showed increased population density and longevity of individuals on the burnt site. Adult and seedling populations of both species showed greater survival in the burnt plot. Eupatorium riparium survived better than E. adenophorum adults after burning. In the unburnt plot, however, the seedling survival of both species was nil. The heavy juvenile mortality of both species in the unburnt situation is attributed to the accumulation of a thick layer of pine needles and the growth of herbaceous vegetation. Moisture stress and low temperature in winter months also seem involved in the regulation of seedling population of these two weeds.
Germination response of Galium spurium L. to light
Authors: MALIK N. , BORN† W. H. VANDEN 
Published: July 2006

SummaryThe effects of intensity, duration and spectral quality of light were investigated on the germination of Galium spurium L. Light inhibited germination and the degree of this inhibition was related to the intensity and duration of exposure to light beyond the initial 36‐h imbibition period. Subsequent dry storage for up to 7 weeks and reincubation in the dark did not remove this inhibitory effect, indicating that a secondary dormancy was induced by continuous exposure to light. Germination was completely inhibited with intermittent 1‐h exposures of light every 3, 7 or 11 h for 8 days. Red, far‐red and blue light inhibited germination and the degree of inhibition was related to the duration of exposure. Far‐red light was more inhibitory than red or blue light. Green light promoted germination slightly. Nitrate salts in the medium during light exposure did not prevent the onset of light‐induced dormancy. In subsequent dark incubation, light‐induced dormancy was overcome by the addition of nitrates and, to a lesser extent, by kinetin and GA3.
Use of activated carbon to protect tomato against metribuzin
Authors: TOTH J. , MILHAM P. J. , HILLIAR G. R. , KALDOR C. J. 
Published: July 2006

SummaryProtection of tomato (Lycopersicon esculentum Mill., cv. UC 134) against metribuzin was increased by placing a small quantity of activated carbon near each seed position before pre‐emergent application of the herbicide. The most protective location of the carbon was the surface of the soil, immediately above the seed. In this location, 0.10 g of activated carbon protected tomatoes from the phytotoxic effects of 0.700 kg metribuzin ha−1 whereas, without the activated carbon, 0.175 kg metribuzin ha−1 killed both tomato and blackberry nightshade (Solanum nigrum L.). Placing plastic discs in this location did not reduce the phytotoxicity; however, a barrier that prevented lateral invasion by the herbicide, of the zone of soil through which the plumule emerged, partially protected the plains from 0.350 kg metribuzin ha−1, showing that metribuzin entered the plants in substantial quantities via the plumule as well as the roots. This result suggests that activated carbon maintained a lower metribuzin concentration in the plumule/root zone than the bulk concentration. It also explains way the soil surface was the most protective carbon location. These findings provide the basis for extending the use of preemergent herbicides to situations in which previously they could not be used safely or economically.
Influence of herbicide treatments on the population dynamics of Avena stériles ssp. ludoviciana (Durieu) Nyman in winter wheat crops
Authors: FERNANDEZ‐QUINTANIllA C. , NAVARRETTE L. , TORNTER C. , ANDUJAR J. L. 
Published: July 2006

SummaryA long‐term study was conducted during 4 consecutive years to determine the effects of herbicides on the major demographic parameters and on the dynamics of the populations of Avena sterith ssp. ludoviciana (Durieu) Nyman growing in winter wheat crops in Central Spain. The three herbicides tested bad different effects on the life cycle of the plant. Tri‐allate was moderately effective in reducing seedling recruitment and seedling survivorship, but it resulted in adult fecundities similar to or higher than, those of the check plots. Difenzoquat was highly effective in reducing plant survivorship and it consistently reduced the reproductive capacity of the survivors. Flamprop‐isopropyl L was not very effective in reducing plant survivorship, but it had the largest influence on adult fecundity. Overall, although the three herbicides were able to reduce substantially (59–95%) the production of new seeds, large numbers of seeds were returned annually to the soil in all the treatments. The annual application of any of the three compounds during 4 consecutive years had a marked effect on the long‐term evolution of the populations of buried seeds in the soil, emerged seedlings, mature plants and new seeds produced. Continuous herbicide application resulted in a gradual depletion of the seed bank of A. sterilis in the soil. At the end of the 4‐year period, buried seed populations in the herbicide‐treated plots were (61–81%). lower than those at the beginning of the experiment, and 92–95% lower than those of the check plots at the same lime. However, the seed reserves present in the treated plots were Mill high enough to require some type of control programme.
Effect of fire on population dynamics of Mikania micrantha H.B.K. during early succession after slash‐and‐burn agriculture (jhum) in northeastern India
Authors: SWAMY P. S. , RAMAKRISHNAN P. S. 
Published: July 2006

Summary: Résumé: ZusammenfassungThe population size of Mikania micrantha H.B.K. is considerably enhanced by fire in 2‐, 4‐ and 8‐year‐old fallows developing after slash‐and‐burn agriculture (jhum) in northeastern India. The recruitment pattern in burnt and unburnt sites in each fallow differed. Seedling recruitment was restricted only to burnt sites in 2‐ and 4‐year‐old fallows, whereas it occurred in both burnt and unburnt sites in an 8‐year‐old fallow. Sexual reproductive potential of the species was affected by the age of the fallow and by fire in each fallow plot. These results are related to micro‐environmental changes in the habitat as a consequence of fire in different fallow plots. Effet du feu sur la dynamique des populations de Mikania micrantha H.B.K. dans un mode de conduite alternatif coupe‐brulage dans le nord‐est de l'IndeL'importance des populations de Mikania micrantha a été considérablement augmentée par le feu dans des vieilles jachères de 2, 4 et 8 ans conduites selon la technique coupe‐brûlage dans le Nord‐Est de l'Inde. Le processus de reprise dans les zones brûlées et non brûlées a été différent pour chacune des jachères. La reprise de plantules n'a eu lieu que dans les zones brûlées pour les jachères vieilles de 2 et 4 ans. mais elle est survenue en tout lieu dans la jachère de 8 ans. Le potentiel de reproduction sexuée a été affectéà la fois par l'âge de la jachère et par le feu dans chaque parcelle. Ces résultats sont liés à des changements microenvironnementaux dans l'habitat, conséquence du feu dans les différentes parcelles en jachère. Der Einfluss von Feuer auf die Populationsdynamik von Mikania micrantha H.B.K. während der Frühentwicklung einer Folgevegetation nach Brandhackbau in NO‐IndienDie Populationsdichte von Mikania micrantha H.B.K. wird nach Rodung und Abbrennen auf 2, 4 und 8 Jahre altem Brachland durch Feuer beträchtlich erhöht. Auf den einzelnen Brachflächen war die Wiederbesiedelung von abgebrannten und nicht abgebrannten Parzellen verschieden. Die Entwicklung einer Sämlingspopulation war auf 2 resp. 4 Jahre altem Brachland auf abgebrannte Flächen beschränkt, während auf 8 Jahre alter Brache sowohl auf abgebrannten als auch nicht abgebrannten Flächen die Entwicklung einer Sämlingspopulation stattfand. Die sexuelle Reproduktionskraft der Species wird durch die Dauer der Brache und die Wirkung des Feuers beeinflusst. Diese Ergebnisse stehen in Beziehungzu kleinflächigen Umweltveränderungen im Biotop, als Folge des Feuers und des Alters der Brache.
Metabolism of chlortoluron in tolerant species: possible role of cytochrome P‐450 mono‐oxygenases
Authors: GONNEAU M. , PASQUETTE B. , CABANNE F. , SCALLA R. 
Published: July 2006

SummaryPathways of chlortoluron metabolism were compared in excised leaves of four tolerant species, namely wheat (Triticum aestivum var Clement), Bromus sterilis, Galium aparine and Veronica persica. The herbicide was principally detoxified by hydroxylation of the ring methyl in wheat and by N‐dealkylation in Veronica persica. Both pathways were involved in Bromus sterilis and Galium aparine. Kinetic study of the degradation showed that capacity to form non‐toxic conjugates could, at least partially, explain the tolerance of these species to chlortoluron. In plants treated with 1‐aminobenzotriazole, a cytochrome P‐450 enzyme inactivator, N‐dealkylation of chlortoluron was little or not affected, but ring methyl hydroxylation was strongly inhibited. This suggests that at least two distinct enzymatic systems could participate in this metabolism. Moreover, cytochrome P‐450 enzymes could be involved in the ring methyl hydroxylating reaction.
Studies on competition between wheat and Chenopodium album L.
Authors: BHASKAR* A. , VYAS K. G. 
Published: July 2006

SummaryInterspecific competition between wheat (Triticum aestivum L.) and Chenopodium album L., was studied in pots using the replacement series design of de Wit. Competitive interference for phosphorus, and to some extent for nitrogen, between the two species was noted. This played a major part in limitation of growth of wheat plants by C. album, whereas wheat exhibited greater non‐competitive interference in restricting potassium uptake by the weed. Increasing interference from the weed resulted in significant reductions in wheat grain size and yield.
Study of seasonal variation in dormancy of Spergula arvensis L. seeds in a condensed annual temperature cycle
Authors: KARSSEN C. M. , DERKX M. P. M. , POST† B. J. 
Published: July 2006

SummaryChanges in dormancy of Spergula arvensis seeds were studied during pre‐incubation at constant temperatures and under a temperature regime that condensed the annual temperature cycle into 73 days. Each day in the regime represented the mean day and night temperatures and day lengths of 5 successive days of an average year in The Netherlands. Incubation occurred in water or loamy sand, in darkness. Germination of the seeds was tested in water or KNO3 over a range of temperature. Seeds were irradiated with saturating doses of red light. In half of the treatments, pre‐incubated seeds were dehydrated at the transfer to the conditions of the germination test. Breaking of dormancy occurred under conditions of 'spring'. It did not depend on exposure to low‘winter’temperatures, but was induced by rising 'spring’temperatures. Seeds developed secondary dormancy in late‘autumn'. The expression of the changes in dormancy that were induced during pre‐incubation depended on the conditions of the germination test. Light, nitrate and dehydration stimulated germination. The experiments predicted that field emergence from nitrate‐poor soils that have not been dehydrated will be restricted to a short period in autumn, whereas disturbance of nitrate‐rich soils followed by a dry spell will stimulate germination of S. arvensis seeds from early spring to late autumn. The data presented good explanations for the cosmopolitan character and the serious weediness of this species. Its classification as a summer or winter annual is discussed.
Floristic composition and agricultural importance of weeds in southern Spain
Authors: SALVÁ A. PUJADAS , HERNÁNDEZ BERMEJO J. E. 
Published: July 2006

Summary: Résumé: ZusammenfassungA survey was made of the agrestal and ruderal flora of southern Spain, mainly in the province of Córdoba, and a total of 941 weed species in 81 families were found in ecosystems showing severe human disturbance. The families with the highest numbers of species were Compositae, Leguminosae and Gramineae; other families like Amaran‐thaceae, Solanaceae and Oxalidaceae were also important because of their special behaviour as weeds. An assessment of the agricultural importance of the species in terms of the damage caused to crops showed that 36,3% could be considered rare or casual, 15,6% slightly harmful, 14,1% locally harmful. 7,3% harmful, and 26,6% very harmful. The richness of the flora in the different ecosystems is analysed and compared with that in other countries.Composition floristique et importance agronomique des adventices dans le Sud de l'EspagneUne enquête a été conduite sur la flore agreste et ruderale dans le Sud de l'Espagne, principalement dans la province de Cordoue, et un total de 941 espèces d'adventices de 81 familles ont été trouvées dans des écosystèmes fortement influencés par l'intervention des hommes. Les familles les plus riches en espèces étaient les composées les légumineuses et les graminées: d'autres familles, comme les amaranthacées, les solanacées el les oxalidacées avaient également de l'importance en relation avec leur comportement particulier en tant qu'adventices. Une estimation de l'importance agricole des espèces en terme de nuisances provoquées aux cultures, montre que 36,3% peuvent être considérées comme rares ou occasionnelles, 15,6% comme faiblement dangereuses, 14,1% comme localement dangereuses, 7,3% comme dangereuses et 26,6% comme extrêmement dangereuses. La richesse de la flore dans différents écosystèmes est analysée et comparée à ce qui se passe dans d'autres pays.Floristische Zusammenseizung und landwirtschaftliche Bedeutung von Unkräutern in SüdspanienDie Segetal‐ und Ruderalvegetation in Südspanien, vor allem in der Provins Cordoba, wurde aufgenommen, wobei insgesamt 941 Unkrautarten aus 81 Familien in den am meisten vom Menschen beeinflussten Ökosystemen gefunden wurden. Die artenreichsten Familien waren die Compositen, Leguminosen und Gramineen; wichtig waren auch die Amaranthaceen, Solanaceen und Oxalidaceen, weil zu ihnen besonders ausgeprägte Unkrautarten gehören. Im Hinblick auf die landwirtschaftliche Bedeutung, d.h. die Schadwirkung, welche die Arten in Kulturpflanzenbeständen haben, konnlen 36,3% als selten oder gelegentlich und 15,6% als wenig schädlich eingestuft werden, 14,1% als lokal schädlich, 7,3% als schädlich und 26,6% als sehr schädlich. Der Florenreichtum in den verschiedenen Ökosystemen wurde analysiert und mit dem anderer Länder verglichen.
Photosensibilite des bromes annuels (Bromus L. spp.)
Authors: JAUZEIN P. 
Published: July 2006

RésuméUne sensibilisation des agriculteurs au problème des bromes envahissant des céréales nous a incitéà rechercher si les caractéristiques germinatives de ces espèces pouvaient expliquer leur comportement au champ. Cet article étudie plus particulièrement la réponse des bromes à la lunnère. Douze espèces annuelles ont été testées: 6 pour le sous‐genre Bromus, 6 pour le sous‐genre Anisantha Koch; Bromus catharticus Vahl a été rajouté car il peut se comporter comme annuel. La photosensibilité est très marquée surtout à basse température où elle est négative. Les différentes espèces ont été comparées entre elles en tenant compte de leur origine géographique. La photosensibilité négative est beaucoup plus importante pour le sous‐genre Anisantha Koch et pour les lots d'origine méditerranéenne. L'intensité et la persistance de ce phénoméne lui permettent certainement de jouer un rôle non négligeable dans le comportement de ces graminées en milieu naturel.
Untersuchungen zum Einfluss einer Pflanzenschutzmittelspritzfolge auf das Rückstandsverhalten von Terbutryn und die mikrobielle Aktivität im Boden. Teil II. Beeinflussung der mikrobiellen Aktivität
Authors: AUSPURG B. , PESTEMER W. , HEITEFUSS R. 
Published: July 2006

ZusammenfassungLaborversuehe zum Einfluß von Terbulryn unter verschicdenen Inkubationsbedingungen (10 und 20°C; 30 und 60% WKmax) auf die mikrobielle Aktivität des Bodens (Dehydrogenaseaktivität, Atmung nach Glukosezugabe, N‐Umsatz) lifeßen selbst bei der zehnfachen Aufwandmenge kaum Beeinträchtigungen der Mikroflora in zwei unter‐sehiedlich sorptiven Böden erkennen. Demgegenüber verursachte Dinoscbacetat—allein und in Kombination mit Terbutryn und weiteren Pflanzenschutzmitteln (Triadimefon, Parathion)—bereits bei der einfachen Aufwandmenge bei allen Inkubationsbedingungen deutliche Hemmungen der Dehydrogenaseaktivität und der Bodenatmung. Nach Anwendung der zehnfachen Aufwandmenge setzte im sorptionsschwachen Boden nach einer anfänglichen Nitrifikationshemmung eine verstärkte Mineralisation bodenbürtigen Stickstoffs ein. Triadimefon und Parathion riefen sowohl Hemmungen als auch Stimulationen der mikrobiellen Aktivität hervor, die sich auch in den Kombinationen mil den übrigen Pflanzenschutzmitteln bemerkbar machten, deren Ursachen aber nicht eindeutig zu klären waren. Im Freiland konnten die Beeinflussungen der Bodenatmung und der Dehydrogenaseaktivität in ihrer Tendenz bestätigt werden, wobei eine deutliche Wiedererholung zu erkennen war. Die Dehydrogenaseaktivität reagierte insgesamt am empfindlichsten und ist daher zur Erfassung der Nebenwirkungen von Pflanzenschutzmitteln auf Bodenmikroorganismen gut geeignet. Eine zusätzliche Untersuchung des N‐Umsatzes kann weitere Hinweise für die Interpretation der Ergebnisse geben.
Growth pattern of diploid and tetraploid spotted knapweed, Centaurea maculosa Lam. (Compositae), and effects of the root‐mining moth Agapeta zoegana (L.) (Lep.: Cochylidae)
Authors: MÜLLER H. 
Published: July 2006

SummaryGlass‐faced growth containers were used to study the phenology of three demes of Centaurea maculosa Lam. (Compositae), and the impact of root‐mining by the moth Agapeta zoegana (L.) (Lep.: Cochylidae) on rooting intensity. This moth was recently established in North America for the biological control of spotted and diffuse knapweed, C. maculosa and C. diffusa. The life cycle, biomass production and longevity of the diploid European host plant (monocarpic biennial) and the tetraploid North American target species (polycarpic perennial) differed considerably, providing a possible explanation for the rapid spread of the tetraploid species in North America. Compared to controls, plants of German and Canadian origin infested by A. zoegana showed increased root growth during the mining period and after the emergence of the moths. However, no such difference was found in diploid plants of Hungarian origin. The observed plant reactions partly support, therefore, the hypothesis of a nutritionally controlled response to herbivory. Infested plants did not differ in fecundity compared to controls, but root‐mining tends to reduce the survival rate of immature plants The consequences for the plant population density are discussed.
Estimation of thresholds for weed control in Australian cereals
Authors: STREIBIG J. C. , COMBELLACK J. H. , PRITCHARD G. H. , RICHARDSON R. G. 
Published: July 2006

SummaryA non‐linear model relating crop yield to the density of weeds was fitted to nine Victorian weeds to evaluate their competitive abilities. The weeds were: Acroptilon repens (L.) DC. (creeping knapweed), Chondrilla juncea L. (Skeleton weed, Raphanus raphanistrum L. (Wild radish), lolium rigidum Gaud. (Annual ryegrass), Lithospermum arvense L. (White iron weed), Brassica tournefortii Gouan (Wild turnip), Lamium amplexicaule L. (Deadnettle), Fumaria parviflora Lam. (White fumitory) and Amsinckia hispida (Ruiz & Pav.) I.M. Johnston (Amsinckia). Where more than one experiment was available for a weed, the net return for a herbicide treatment over a range of weed densities was calculated to obtain the economic threshold density.Generally, the economic threshold densities within a weed species were the same order of magnitude, except for the perennial Chondrilla Juncea L., For this species data were collected in years of contrasting rainfall. The model used here is discussed in view of the threshold approach currently used in continental Europe.
Effect of sucrose taken up by developing Avena fatua L. panicles on the dormancy and α‐amylase synthesis of the seeds produced
Authors: CAIRNS A. L. P. , de VILLIERS O. T. 
Published: July 2006

SummaryDormancy of seeds harvested from excised Avena fatua panicles grown in solutions containing sucrose increased with increasing concentrations of sucrose. Induction of this sucrose‐imposed dormancy could be partially inhibited by the inclusion of GA4/7 in the growing medium. The sucrose‐grown seeds were fully viable and dormancy could be broken by methods commonly used to break dormancy, such as treatment with GA3 or dehusking and pricking the caryopsis. Low concentrations of sucrose added to the incubation medium stimulated GA3‐induced α‐amylase synthesis in mature de‐embryonated A. fatua caryopses but higher concentrations inhibited it. The relevance of these findings to the explanation of the environmental component of A. fatua seed dormancy is discussed.