CHEMICAL AND BIOLOGICAL PROPERTIES OF TWO NEW HERBICIDES—IOXYNIL AND BROMOXYNIL     

K. CARPENTER  HELEN J. COTTRELL  W. H. DE  SILVA  B. J. HEYWOOD  W. G. LEEDS  K. F. RIVETT  MARGERY L. SOUNDY 《Weed Research》1964,4(3):175-195

Summary. The preparation of ioxynil, bromoxynil, and their salts is described, and information on solubilities and stability to storage is summarized. Although the toxicology of the herbicides is to be reported in greater detail, a preliminary statement is made here. Evidence of herbicidat activity under glasshouse conditions is indicated briefly, and supports the conclusion that both compounds are effective when applied to the foliage of a wide range of dicotyledon weed species. Seedlings of some weed species resistant to the phenoxy alkanoic acids are controlled under glasshouse conditions at doses as low as 0.125 lb/ac, and ioxynil has a wider range of activity than bromoxynil at these low doses. Graminaceous species tolerate 4–8 lb/ac of both herbicides without injury, and certain leguminous crops tolerate one or other herbicide at doses of 0.5–0.75 lb/ac. The contact action of the herbicides is rapid, there are also slower systemic effects, and seed germination is inhibited. In susceptible species the level of post-emergence activity is shown to be influenced by the growth stage of the weed, the distribution of herbicide on the foliage, and environmental factors of which light intensity appears to be most important.
Propriétés chimiques et biologiques de deux nouveaux herbicides: ioxynil et bromoxynil  相似文献   

Demography and control of Cirsium vulgare (Savi) Ten. in relation to grazing     

F. FORCELLA  HELEN WOOD 《Weed Research》1986,26(3):199-206

Cirsium vulgare (Savi) Ten. is a serious biennial alien weed only in pasture land in Australia. To identify reasons for such preferential infestation and to isolate sensitive stages in the life history of C. vulgare, comparative demographic analyses were conducted in grazed, ungrazed and herbicide-treated Mediterranean-like pastures in south-eastern Australia. Grazing by sheep (i) reduced competition from neighbouring plants, (ii) increased C. vulgare growth, flowering and seed (achene) production, and (iii) promoted survival of C. vulgare seedlings. The most sensitive period in the life of C. vulgare appears to be the transition from the seedling to rosette life stages where, for example, an average survival rate of only 0.2 and 1.0% occurred in ungrazed and grazed pastures, respectively. In contrast, 10 and 15% of seeds successfully emerge on average as seedlings, and 49 and 51% of rosettes successfully develop into adult plants. Control of C. vulgare with dicamba was most effective just after initiation of autumn rainfall. This time corresponds to the period of naturally high seedling mortality in C. vulgare induced by competition from neighbouring plants. Démographie de Cirsium vulgare (Savi) Ten. et sa maîtrise par rapport au pâturage Cirsium vulgare (Savi) Ten. est une mauvaise herbe bisannuelle en Australie, d'origine étrangère, mais elle n'est importante que dans les pâtures. Dans le but de déterminer les raisons de cette préférence et d'établier les stades sensibles dans le cycle de C. vulgare, des analyses démographiques ont été entreprises au sud-est de l'Australie dans des pâtures de type méditerranéen. Le pâturage des moutons a diminué la concurrence des plantes voisines, rendu plus importantes la croissance de C. vulgare ainsi que sa floraison et la production de graines (akènes) et favorisé la survie des jeunes plants adventices. Il parait que le stade le plus sensible de la vie de C. vulgare est la période de transition du stade jeune plant au stade rosette, où le taux moyen de survie était de 0,2% sans et 1% avec pâturage. Par contre, une levée de 10 et 15% des graines a été constatée et 49 et 51% des rosettes deviennent des plantes adultes. Le dicamba s'est montré le plus efficace contre C. vulgare en application juste après le commencement des pluies d'automne, époque d'une forte mortalité naturelle parmi les jeunes plants, provoquée par la concurrence des plantes voisines. Populationsdynamik und Bekämpfung von Cirsium vulgare (Savi) Ten. unter Bezug auf Beweidung Cirsium vulgare tritt in Australien nur in Weideland als wichtiges, zweijähriges, adventives Unkraut auf. Um Ursachen für die selektive Besiedelung von Grasland und um empfindliche Entwicklungsstadien im Entwicklungszyklus herauszufinden, wurden in SO-Australien vergleichende populationsdynamische Untersuchungen in beweidetem, unbeweidetem und mit Herbiziden behandeltem Grasland von mediterranem Typus durchgeführt. Die Beweidung durch Schafe hatte zur Folge, dass (i) die Konkurrenz durh benachbarte Pflanzen verringert, (ii) das Wachstum, Blühen und die Samenproduktion von C. vulgare gesteigert und (iii) die Ueberlebensrate von C. vulgare-Sämlingen erhöht wurden. Es scheint, dass im Entwicklungszyklus von C. vulgare der Uebergang vom Sämlings-zum Rosettenstadium die empfindlichste Phase darstellt, in der nur 0,2% in unbeweidetem. resp.1% in beweidetem Grasland überleben. Die Keimungsrate hingegen beträgt im Mittel 10 und 15% und 49 und 51% der Jungpflanzen im Rosettenstadium entwickeln sich zu adulten Exemplaren. Die Bekämpfung von C. vulgare mit Dicamba erwies sieh kurz nach Beginn der herbstlichen Regenfälle als am wirksamsten. Dieser Zeitpunkt entspricht einer Periode erhöhter, natürlicher Keimlingsmortalität, bedingt durch eine verstärkte Konkurrenzierung durch benachbarte Pflanzen.  相似文献   

Characteristics distinguishing invasive weeds within Echium (Bugloss)   总被引：1，自引：0，他引：1  

F. FORCELLA  J. T. WOOD  S. P. DILLON 《Weed Research》1986,26(5):351-364

Plant quarantine agencies attempt to regulate the continuing worldwide problem of spread of alien plants, but systems of plant quarantine have not been based entirely on objective criteria. Comparative epidemiological research of known alien weeds may provide such criteria and thereby improve the success of plant quarantine. For this reason biogeographical and ecophysiological data were gathered and analyzed for Echium (Boraginaceae), especially for the three differentially distributed and weedy species in Australia: E. italicum L. (rare), E. vulgare L. (uncommon), and E. plantagineum L. (common). Such data included the following: native distributions in Eurasia and North Africa, historical spread in Australia, seed germination, vegetative growth and propensity to flower. Quantitative plant characteristics which distinguish weedy species of Echium from their innocuous counterparts, and whose values could most easily be determined by plant quarantine officials, are the breadth of native distribution and rapidity of seed germination. Although these results were derived from only a few temperate taxa, they may apply in principle to many species. Caractères distinctifs des mauvaises herbes envahissantes dans le genre Echium Des agences de mise en quarantaine de végétaux s'attachent à contrôler le problème permanent à travers le monde de la propagation des végétaux étrangers; cependant, les systèmes de quarantaine n'ont pas étéétablis exclusivement sur des critères objectifs. Des études d'épidèmiologie comparatives pour des adventices étrangères connues peuvent fournir de tels critères et ainsi accroître le succès de la mise en quarantaine des végétaux. Pour cette raison, des données biogéographiques et écophysiologiques ont été regroupées et analysées pour le genre Echium (Boraginacée), en particulier pour trois espèces de mauvaises herbes différemment réparties en Australie: E. italicum L. (rare), E. vulgare L. (peu répandu), E. plantagineum L. (commun). Parmi ces données, on trouvait les suivantes: répartition originelle en Eurasie et en Afrique du Nord, historique de la propagation en Australie, germination des semences, croissance végétative et propension à fleurir. Les caractéristiques quantifiables qui permettraient de distinguer les espèces nuisibles d'Echium de leurs équivalents inoffensifs et dont les valeurs pourraient très aisément être déterminées par les organismes officiels responsables des quarantaines sont: l'ampleur de la distribution d'origine et la rapidité de la germination des semences. Bien que ces résultats proviennent de seulement quelques taxons, ils peuvent être appliqués, en principe, à de nombreuses espèces. Merkmale zur Definition schädlicher Arten in der Gattung Echium (Natterkopf) Pflanzenquarantäneämter versuchen das weltweite Problem der Ausbreitung von eingeschleppten Pflanzen zu kontrollieren; die Quarantän-evorschriften sind jedoch nicht völlig auf objektiv erfassbare Kriterien abgestützt. Vergleichendc epidemiologische Erforschung von Adventivpflanzen kann derartige Kriterien liefern und damit den Nutzeffekt von Quarantänemassnahmen verbessern. Zu diesem Zweck wurden für die Gattung Echium (Boraginaceen) biogeographische und ökophysiologische Daten gesammelt und analysiert; es wurden dabei speziell die drei in Australien als Unkräter geltenden und verschieden verbreiteten Arten E. italicum L. (selten). E. vulgare L. (gelegentlich vorkommend) und E. plantagineum L. (häufig) untersucht. Der Datenkatalog enthielt Angaben über: die ursprüngliche Verbreitung in Eurasien und N-Afrika, Geschichte der Ausbreitung in Australien, Samenkeimung, vegetatives Wachstum und Blühbereitschaft. Der Ausdehnungsbereich der ursprünglichen Vorkommen und die Geschwindigkeit der Samenkeimung sind quantitativ erfassbare, durch Quarantäncbeamte leicht zu bewertende, Kriterien zur Unterscheidung zwischen unschädlichen und als Unkräuter schädlichen Echium-Arten. Obwohl diese Ergebnisse nur von relativ wenigen, unter temperierten Bedingungen vorkommenden, taxonomischen Einheiten abgeleitet worden sind, mögen sie im Prinzip für viele Arten Gültigkeit haben.  相似文献   

A SUSPECTED CASE OF ENOSTOSIS IN A GERMAN SHEPHERD DOG     

A. K. W. WOOD  W. L. PORGES 《Australian veterinary journal》1981,57(7):349-350

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Diaphragmatic hernia. Analysis of fifty-six cases in dogs and cats   总被引：1，自引：0，他引：1  

HELEN L. GARSON  N. H. DODMAN  G. J. BAKER 《The Journal of small animal practice》1980,21(9):469-481

A review of fifty-six cases of diaphragmatic hernia in the dog and cat is presented. These were admitted to the University of Glasgow Veterinary School between January 1972 and August 1978. Fifty-three of these cases were treated surgically but only twenty-nine survived to be discharged from the hospital. The reasons for the low survival rate are discussed in detail.  相似文献   

Field and wind tunnel assessments of the implications of respacing and thinning for tree stability   总被引：5，自引：0，他引：5  

GARDINER  B. A.; STACEY  G. R.; BELCHER  R. E.; WOOD  C. J. 《Forestry》1997,70(3):233-252

The change in wind loading on trees due to tree spacing andwind speed was examined in the field and in the wind tunnel.The field measurements were made in small blocks of Sitka sprucerespaced 15 years previously to different stand densities. Thewind tunnel measurements were made with dynamically correct20-cm tall plastic trees. The maximum bending moment on treesshowed a linear increase with the ratio of spacing to height.Estimates suggest that at the wider spacing tree diameter hasincreased sufficiently so that trees are less likely to break.However, the increase in resistance to overturning is not asrapid as the increase in wind loading and wider spaced treeswill be more vulnerable to overturning. Wind tunnel measurementswere also carried out on a range of commercial thinning practicesand showed that the critical factor in reducing stand stabilityis the size of gap made in the forest. The mechanical and dynamiccharacteristics of trees at different spacing are presented.These show that with increasing spacing the Young's modulusof trees decreases and their damping coefficient increases.This illustrates that wide spaced trees have weaker wood thanclose spaced trees but they are less reliant on the supportof neighbouring trees. The implications of the measurementson the overall stability of stands and the implications forforest managers are discussed.  相似文献   

Reply     

LA CORNER  PR WOOD  JS ROTHEL 《Australian veterinary journal》1991,68(6):218-219

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A survey of clover and Lotus rhizobia in Northern Ireland pasture soils     

M. WOOD  J. E. COOPER  D. S. CAMPBELL 《European Journal of Soil Science》1985,36(3):357-365

192 sites covering the main soil types in Northern Ireland were analysed for numbers and effectiveness of clover and Lotus rhizobia, and chemical properties. Peat sites were generally highly acid (pH <5.5) and mineral sites near neutral (pH 5.5–7.8). Clover rhizobia were generally absent from peat sites and present in mineral sites as large populations (> 10⁶ g^?1 dry soil). 79% of isolates were effective on T. repens var. Grasslands Huia. Lotus rhizobia were generally absent from peat sites, less often present than clover rhizobia in mineral sites, and as smaller populations. They were mainly effective on L. pedunculatus var. G4705 and were all of the slow-growing type belonging to the genus Bradyrhizobium. Numbers of clover rhizobia were significantly correlated with soil pH, exchangeable Ca, base saturation and Al saturation, but effectiveness of clover rhizobia and numbers of Lotus rhizobia were not correlated with any soil chemical property.  相似文献   

Provisional audiogram for the shark,Carcharhinus leucas     

KRITZLER H  WOOD L 《Science (New York, N.Y.)》1961,133(3463):1480-1482

In an operant-conditioning study, a bull shark responded to signals at frequencies between 100 and 1500 cy/sec. In its band of greatest sensitivity (400 to 600 cy/sec), it discriminated, from high-level ambient noise, signals of amplitudes which the apparatus could not measure.  相似文献   

Surface phagocytosis; its relation to the mechanism of recovery in pneumococcal pneumonia     

WOOD WB  SMITH MR  WATSON B 《Science (New York, N.Y.)》1946,104(2689):28-29

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