摘要:

Résumé.Sur un assolement quadriennal a étéétudié l'évolution de la flore adventice au cours d'une année culturale et au cours d'une rotation cullurale complète. Les plantules apparues en avril ne représentent que 7,4% en moyenne pour les cultures d'automne et 28,7% en moyenne pour les cultures de printemps, du nombre de semences viables susceptibles dc germer à cettc date; ces icvées ne représentent que 5,6% en moyenne du stock total de graines viables contenues dans les 10 premiers centimétres de sol. Aprèes 5 années de désherbage, la flore adventice mesurée par le nombre de plantules apparuea en avril avant les traitements herbicides montre une très grande stabilité tant qualitative que quantitative; seules les espéces vivaces se sont considérablement dévelopées les parodies non désherbées.Vergleich der Entwicklung einer Unkraulflora mit und ohne ch

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01195.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Summary.Root fragments less than 5 mm long were unable to form shoots. However, shoots were produced by fragments 10 mm long and 1 mm in diameter, unless originating from immature apical regions. The number of shoots per unit length of root was greater if the root was cut into many small pieces than into a few long ones. The ability to produce shoots was apparently unrelated to the presence or absence of visible buds.Root fragments showed polarity; most of the shoots originated from the basal (proximal) end and the roots from the apical (distal) end. Soil moisture content had relatively little effect upon growth from a fragment unless the soil was waterlogged or very dry for prolonged periods. Growth from fragments was prevented by temperatures below 5°C; optimum growth occurred at 15°G. Shoots from fragments 25 mm long emerged successfully from depths of 50 cm.Capacité de régenération de fragments de racinesde Cirsium arvense(L.)

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01196.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Summary.In a field experiment with different densities ofAlopecurus myosuroides, 10 plants/m2caused no significant reduction in total dry weight of winter wheat at harvest. When autumn‐ or spring‐germinated plants at 100/m2remained until harvest, crop weight was reduced by about 30%. A study of root‐zone competition betweenA. myosuroidesand winter wheat in the glasshouse showed that suppression of the weed by the crop was greater at high nitrogen levels; the practical implications of this are discussed.La nature de l'interférence d'Alopecurus myosuroïdesHuds. sur la croissance du blé d'hiver, et ses con

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01197.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Summary.Two trials comparing grass control by trifluralin and carbetamide in autumn‐sown legumes (Trifolium subterraneumL.,T. pratenseL.,T. repensL.,T. dubiumL. andLotus pedunculatusCav.) were conducted. Trifluralin was used pre‐sowing and carbetamide both pre‐sowing and post‐emergence.Both herbicides gave good control ofLolium perenneL. andPoa annuaL. at rates of 0·5 and 1·0 kg/ha a.i. for trifluralin and carbetamide respectively. Carbetamide showed no toxicity to any of the legumes up to 2·0 kg/ha except forLotus pedunculatusat that rate, whereas trifluralin was toxic to all species at 2·0 kg/ha. Neither herbicide controlled broad‐leaved weeds.The results are discussed in terms of the effects of soil fertility, plant age and maturity on the activity of these herbicides.La lutte contre les graminées adventices avec la trifluraline et le carbétamide dans les légumineuses

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01198.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Summary.The effects of pre‐sowing incorporated applications of trifluralin and carbetamide on the growth and nodulation ofTrifolium pratenseL.,T. repensL.,T. dubiumL. andLotus pedunculatusCav. were examined. At rates of 1·0 and 2·0 kg/ha a.i. of trifluralin and carbetamide respectively, nodulation and growth of all legumes was reduced. Root dry weight/plant and nodules/plant were positively correlated, suggesting that the herbicides affected plant growth but not the soil rhizobial population. There were several herbicide rate × legume species interactions.Effets des herbicides trifluraline et carbétamide sur la formation de nodosités et la croissance des plantules de légu

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01199.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Summary.Translocation of 3‐amino‐1,2,4‐triazole‐5‐14C (14C‐aminotriazole) was compared to that of14C‐assimilates in couch grass (Agropyron repens(L.) Beauv.) at three different growth stages.Assimilates of14CO2were translocated from the treated shoot to other shoots and rhizomes at the 2–3‐leaf and 3–4‐leaf stages of development. Much less labelled material was translocated into untreated shoots at the 5‐leaf stage. More14C‐assimilates were translocated to the roots than to untreated shoots at all developmental stages. The translocation patterns of14C‐aminotriazole and14C‐assimilates were similar.Two metabolites, A and B, were formed from14C‐aminotriazole, which chromatographed identically to previously described metabolites inCirsium arvense(L.) Scop. A was further metabolized into B. Labelled aminotriazole and its two metabolites were translocated throughout the plants. Metabolite A was phytotoxic when concentrated and re‐applied to couch grass, but its properties were not those of Unknown II fromCirsium arvense.They were the same as those of Unknown III. Whether or not metabolite A and Unknown III are identical was not established.Migration des substances assimilables marquées au14C, du 3 amino‐1,2,4‐triazole et

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01200.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Summary.The root and shoot growth of oat (Avena sativaL.) and green foxtail (Setaria viridis(L.) Beauv.) were generally reduced proportionately to the concentration of chlorthal dimethyl applied. Foxtail shoot growth was stimulated by a concentration of 2 ppm. Cells in the shoot and root meristems of treated plants were completely disarranged and considerably hypertrophied. Differentiation was irregular and extended nearer the apices in tissue of treated seedlings than in normal tissue. Histochemical tests showed that the amount of starch, proteins and nucleic acids in seedling tissue decreased with an increase of chlorthal dimethyl concentration, whereas the endosperm of the seeds retained more starch and protein than the controls. The walls of shoot nieristem and root epidermal cells were thickened or altered so as to stain more intensely than corresponding cells in untreated tissue.Effet du diméthyle chlorthal sur l'anatomie des plantules d'avoine et de séai

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01201.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Summary.Copper sulphate (GUSO4.5H2O) and sodium hydroxide (NaOH) were used to test the performance of a split‐root method for evaluating the effectiveness and phytotoxicity of root‐active herbicides. This method involves a vertical separation of the root system of weeping willow (Salix babylonicaL.) cuttings. One section is treated with the herbicide dissolved in half‐strength Hewitt's medium while the other remains in medium without herbicide during the test period. Roots are assayed with 2,3,5‐triphenyttetra‐zolium chloride 24 h after treatment to determine their viability. Both herbicides satisfactorily reduced the viability of the treated roots as measured by the quantity of formazan extracted. Copper sulphate was systemic and injured untreated plant parts; sodium hydroxide affected only treated roots. The split‐root tetrazolium method is relatively rapid and does not require sophisticated laboratory equipment.Méthode au tétrazolium sur portions de racines pour l'évaluation de l'efficacité et de la phytotoxicité des herbicides agissan

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01202.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Zusammenfassung.Die Bekämpfung vonGalium aparineL. mit Mecoprop im Nachauflaufverfahren ist abhangig sowohl von der Pflanzengrösse ab auch vor allem vom Boden, in dem die Pflanzen wachsen:1 Kleine Pflanzen werden leichter vernichtet als grosse.2 Pflanzen, die auf einem Boden mit hohem organischen Anteil wachsen, sind gegen Mecoprop widerstandsfähiger als solche, die auf einem Boden mit niedrigem C‐Gehalt wachsen.3Ein Teil der im Nachauflaufverfahren gespritzten Herbizidmenge gelangt auf den Boden und wirkt zusätzlich durch Aufnahme über die Wurzeln.4Diese zusätzlichc herbizide Wirkung ist auf den Bodenproben I und II mit hohem organischen Anteil geringer als auf dem Boden mit niedrigem C‐Gehalt. Als Ursache der geringeren Wirksamkeit ist eine verstärkte Adsorption des Mecoprop in den Bodenproben I und II gegenüber Boden III verantwortlich.5Als Adsorbens kommt nur die organlsche Substanz der Bodenproben in Frage.Der zu erzielende Gesamtbekämpfungserfolg hängt neben der Aufnahme des Mecoprop über das Blatt auch von der zusätzlichen Wirkung des Herbizids über den Boden ab.Control ofGalium aparinewith mecoprop in

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01203.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Summary.The root and shoot growth of oat (Avena salivaL.) and squash (Cucurbita maximaDuchesne) was reduced in proportion to propachlor concentration. Corn (Zea maysL.) root growth was inhibited only by concentrations of 16 ppm and higher. Cell division in onion (Allium cepaL.) root tips was reduced by propachlor and totally inhibited by 16 ppm. Auxin‐induced cell elongation of oat coleoptiles was inhibited in proportion to propachlor concentration. Propachlor treatment prevented the normal senescence of squash cotyledons by inhibiting the autolysis of proteinaceous and lipid reserves.Effets morphologiques, anatomiques et biochimiques du propachlore sur la croissance des plantules Riisum

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1972.tb01204.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY