摘要:

SummaryYoung plants of perennial ryegrass (Lolium perenneL.) absorbed approximately 50% of an application of the grass growth retardant, mefluidide, while from 6.5 to 21.9% of the applied dose was translocated during a 2‐ or 7‐day period respectively. After the 2‐day period 93.4% of extractable radioactivity was identified as mefluidide. This potentially useful chemical was made unavailable as a result of mowing before or after spraying. Mowing before spraying increased the proportion of cut mature laminae and young laminae, neither of which translocated mefluidide to other plant organs as efficiently as intact, mature leaves. Mowing after spraying removed potentially translocatable mefluidide with the cut mature laminae and reduced mefluidide accumulation in untreated plant parts. While mowing treatments may be aesthetically desirable they probably increase the amount of mefluidide necessary for effective growth retard

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1982.tb00162.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

RésuméL'absorption, la métabolisation et la migration dans la plante d'orge d'analogues du propyzamide sont étudiées. Sur une plantule développée, l'absorption est parallèle à la pénétration d'eau. alors que pendant la germination, l'absorption est proportionnelle au paramètre hydrophobique π.Il n'y a pas de différence de migration entre chacun des produits, par contre il y a une différence de métabolisation et le taux de métabolisation est directement lié au paramètre électronique π. Cependant ces variations ne reflètent pas les différences observées sur l'activité biologique globale qui est reliée au paramètre hydrophobique

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1982.tb00163.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

SummaryThe effect of herbicide spray losses on non‐target areas is reviewed. The parameters governing both exo‐ and endo‐losses of herbicides are delineated and the literature on the processes involved is reviewed. The reported studies of droplet drift and vapour drift are assessed. These reviews are then related to the mathematical models developed to describe the spray loss problem. Recommendations are made as to the areas of research needed to improve the predictions of herbicide losses and their ef

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1982.tb00164.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

SummaryWild oat plants of types fA, fB and fC were grown at a constant 15 or 20°C during the period of seed maturation. Seed of the three types differed little in dormancy when grown at 15°C, but at 20°C a larger proportion of seeds of type fA were dormant compared with fB or fC. Overall, dormancy of seed produced at 15 and 20°C was 97 and 63% respectively. Plants of another collection of type fB were grown from seed at 15 or 20°C with or without water stress applied only from the time of panicle emergence. Water stress and high temperature reduced viable seed production. Seed dormancy was tested immediately after collection by planting the seed in soil, and by Petri dish tests. Further Petri dish tests were made after 6 months storage. Seedling emergence in the first autumn from seeds of plants matured without water stress at 15°C was 10% compared with 30% for seeds grown at 20°C. Seeds grown with water stress at 15°C gave 47%, and at 20°C 78% emergence. The majority of emergence from seeds formed at 15°C without water stress occurred in the second spring after burial. Petri dish tests support these findings and suggest that seeds produced in hot dry summers are less dormant than those produced in cool m

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1982.tb00165.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

SummaryIn a collaborative study by 12 laboratories the reproducibility of bioassay techniques was analysed by comparison and statistical treatment of the ED50‐values (μg herbicide/g soil). Commonlyused bioassay techniques were investigated; two direct seeding methods, a transplanting method and a shoot extension method. The herbicides studied were two photosynthesis inhibitors, atrazine and metribuzin usingLepidium sativumandBrassica rapaas test plants; two germination inhibitors, tri‐allate and trifluralin usingAvena sativaas test plant. The mean ED50‐value of atrazine in the direct seeding method was 0.18 with a variation from 0.12 to 0.29 and 0.12 (0.07–0.68) in the transplanting method. The values of metribuzin were 0.05 (0.02–0.11) and 0.03 (0.01–0.15) respectively. The values for triallate were 1.15 (0.50–2.60) in the direct seeding method and 1.10 (0.54–2.53) in the shoot extension method and for trifluralin 3.11 (0.72–18.31) and 1.33 (0.48–2.94) respectively. The reproducibility was best in the shoot extension method. No outliers (confidence intervals lying entirely outside the confidence interval of the overall mean) in the ED50‐values were observed with atrazine and metribuzin when using the direct seeding method, whereas with the germination inhibitors a high number of results (four with tri‐allate, six with trifluralin) could be considered as outliers. A comparison of the use of fresh weight and dry matter showed good agreement between the ED50‐values they gave, wi

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1982.tb00166.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Summary14C‐labelled atrazine or terbuthylazine was applied to the surface of soil columns 100 mm deep and the uptake by oat seedlings measured for up to 24 days after germination following two contrasting rainfall treatments. Attempts were made to predict measured uptake on the basis of mass flow theory given also measurements of transpiration rates, water, rooting and herbicide distribution profiles in the soil, and soil adsorption characteristics. Predictions over a tenfold range of uptake were close enough to suggest that the assumptions made to predict mass flow uptake were essentially correct. Discrepancies appeared to result principally from (i) shoot‐zone uptake, and (ii) incorrect prediction of long‐term herbicide adsorption in undisturbed soil. Greater attention to the effect of herbicide on transpiration rates and to the patterns of water uptake by roots should improve the accuracy of such predictions. The various factors that influence the mass flow uptake of chlorotriazines in the soil surface by seedlings are discussed as a basis for modelling herbicide u

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1982.tb00167.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Résumél'étude par l'électrophorèse du polymorphisme des prolamines (protéines alcoolo‐solubles du grain) a permis de mettre en évidence des modifications de la structure phénotypique d'une population d'Avena fatuaL. au cours de trois années successives. Des corrélations avec les facteurs climatiques et culturaux ont été faites, ce qui a conduit l'auteur à proposer des hypothèses sur les mecanismes d'évolution. Ainsi, le caractère de floraison tardive et de vernalisation est étroitement corréléà l'un des quatre phenotypes principaux de la population, et un autre phénotype présente une sensibilité accrue à certains herbicides des céréales. Ces phénomènes entraineraient le maintien d'un polymorphisme non négligeable. L'analyse des prolamines permet donc de reconnaître des plantes qui ont des comportements écologiques différents, et de prévoir l'évolution des populations d'A. fatuaver

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1982.tb00168.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY