摘要:

Summary.2‐Phenylcarbamoyloxy‐N‐ethylpropionamide, D isomer (11.561 R.P.) was submitted to various physiological tests in order to characterize its properties. Although it does not affect the Hill reaction, it is able to disorganize the plant cell and inhibits tissue differentiation. It penetrates rapidly into susceptible and resistant plants, but the degradation varies with the plant family. It disappears very rapidly from susceptible species, whereas resistant plants accumulate it without any apparent damage. One of its metabolites, aniline, is present in small quantities soon after treatment but is very rapidly eliminated.Studies showed that residues in plants were negligible at harvest.Untersuchungen über Wirkimgsweise und Rückslände des Carbanilsäureesters des D‐Milchsäure‐äthyla

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01381.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Summary.Pre‐emergence application of 2–5 kg/ha (a.i.) of atrazine or simazine was the most effective treatment for control of broad‐leaved weeds in maize. Other triazines injured maize at all rates tested. Among the crops following maize treated with atrazine or simazine at 2–5 kg/ha, sugar beet was injured whereas wheat, oats, vetch, onions and soybeans were not.Post‐emergence application of triazine herbicides was not effective and did not increase maize yields significantly over those of the unweeded plots. Wheat, oats, vetch and sugar beet were injured when following maize treated with post‐emergence sprays; onions and soybeans showed no visible injury except from atrazine or simazine at 5 kg/ha or more, and from mixtures of atrazine+prometryne or atrazine+ametryne at 12–5 kg/ha.Les triazines herbicides sur le mais et leurs arrière‐effets sur les c

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01382.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Summary.Temperatures of 5–6° C delayed leaf necrosis of glasshouse‐grown oats (Avena sativa), winter peas (Pisum sativum), huisache (Acacia farnesiana), mesquite (Prosopis julijiora var. glandutosa), live oak (Quercus virginiana) and yaupon (Ilex vomitoria) for at least 48 hr after treatment with paraquat as compared with higher temperatures. After 96 hr, oats, winter peas, huisache and mesquite at 5° C usually showed as much necrosis as plants at 24–28° C. Similar results were obtained with live oak and yaupon, and with yaupon in the field, except that longer periods were sometimes required for plants at low temperatures to develop injury comparable with that at higher temperatures.Washing yaupon and live oak leaves 1 hr after application reduced the effectiveness of paraquat regardless of temperature, but washing winter peas 10 min after application had little or no effect on phytotoxicity. Field‐grown mesquite showed extensive leaf necrosis when leaves were washed after 20 min, live oak leaves similarly treated and washed were not injured, while the response of winged elm (Ulmus alata) was intermediate.Percentage leaf necrosis of mesquite, winged elm, yaupon and live oak increased with increasing paraquat concentration; 6–9 μg/leaf on mesquite and 20 μg/leaf on winged elm gave 100% necrosis after 4 days. Complete leaf necrosis of live oak and yaupon was not attained during this period even with 80 μg/Ieaf.Nursery‐grown mesquite, yaupon and greenbriar (Smilax bona‐nox) and natural stands of yaupon were treated at two growth stages, in March and May. Paraquat was more effective on mesquite when applied in May, but there were no differences with the other species.Facteurs affectant la

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01383.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Summary.In a 6‐year experiment with a naturally occurring population of viable weed seeds, the numbers in the top 9 in. of soil decreased exponentially from year to year in the absence of further seeding. The rates of loss were equivalent to 22% per year in undisturbed soil, 30% per year on plots dug twice a year (March and September) and 36% per year on those dug four times a year (March, June, September, December). Seed numbers of individual species also decreased exponentially, although not all at the same rates.On the dug plots, the numbers of seedlings that emerged each year decreased exponentially once the regimes had become established. The proportions of the viable seeds which gave rise to seedlings in the course of a year were 7 % on plots dug twice and 9 % on those dug four times a year; although there was some variation, these proportions remained much the same from year to year. On undisturbed soil the number of seedlings that emerged declined rapidly, and in the 4th year represented no more than 03% of the viable seeds still present in the top 9 in. of soi

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01384.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Summary.Factors investigated included the susceptibility of Avena fatua L. at various stages of growth, the amount of moisture needed to activate di‐allate in Regina heavy clay, the vapour action of di‐allate in soil, the effect of organic matter on the availability of di‐allate, and the persistence of di‐allate and tri‐allate in Regina heavy clay.A. fatua sown at depths of 5–15 cm was killed by di‐allate or tri‐allate. as were seedlings treated at the 15–2‐leaf stage. Seedlings of spring wheat (Triticum aestivumL.) survived rates of 24 oz/ac if the shoots were 1–3 cm long prior to exposure.When di‐allate at 16 oz/ac was mixed with a 5 cm layer of Regina heavy clay (wilting point 19–6%) slightly less than 15% soil moisture was required to give complete control of A.fatua. Further experiments indicated that a large percentage of A. fatua seedlings were killed by the action of di‐allate vapour in the soil.In other tests the activity of di‐allate and tri‐allate was reduced when the percentage of organic matter in the soil was increased by adding peat. This could explain why there is little damage to wheat sown in treated soil of high organic content while similar rates can cause extensive damage in soils of low organic content.Under comparable conditions tri‐allate persisted for a longer period in the soil than di‐allate. Both chemicals exhibited a lag period after which their breakdown appeared to follow a first‐order reaction. Differences in the period of persistence were attributed to a much longer lag period and a slightly slower rate of biological breakdown for tri‐allate as compared to di‐allate.Facteurs affectan

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01385.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Summary.We conducted studies to determine the effects on corn (Zea mays L, var. Indiana 654) and pea (Pisum sativum L. var. Alaska) of localizing various herbicides in the soil, using a double plastic pot technique which ensured separate exposure of the root and shoot zones of the plants to treated soil. Effects on corn and pea were similar in relation to site of uptake. 2,4‐D‐amine, naptalam, simazine, diuron and dalapon‐sodium entered primarily through the roots. Some shoot entry and also severe inhibition of roots occurred in soil treated with 2,4‐D and naptalam; these were noticed only to a slight extent with the other three herbicides.EPTC, chlorpropham and trifluraiin were most effective when applied to the shoot zone. Little effect on foliage growth was evident when the root zone alone was treated. However, roots in treated soil were severely inhibited by these three herbicides. Dinoseb displayed a contact type of action, injuring both shoots and roots. Treatment of both zones had an additive effect.Entry of chlorthal‐methyl which was tested on a susceptible species, sorghum (Sorghum vulgare Pers.) was mainly through the shoot, with only a slight effect on top growth when roots alone were treated. Roots in treated soil were slightly inhibited.Localisation de l'absorption des herbicides appliqués

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01386.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Summary.Monthly samples of field‐grown rhizomes and aerial stems of Polygonum amphibium were tested for innate dormancy during parts of 2 years in England and during 5 months of a third year in southern Germany. All stems and rhizomes were cut into two‐node fragments, planted in soil in a warm glasshouse, and the new shoots counted after 3 weeks. Dormancy per month for different categories of stems varied from 0 to 23%, averaging 4–3% for all fragments tested but only 1–3% for mature buds. No evidence of a dormant period was found in either country.Incidence de la darmance dans une tige à deux noeuds et des fragments de rhizome de Polygonum amp

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01387.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Summary.Seeds of Polygonum persicaria from several sources, or from plants subjected to in lain treatments, were chilled for varying periods and incubated for a 3‐week germination test period. Populations differed widely in seed weight and to some extent in the response to different periods of chilling. No relationship between this response and the climate of the locality of origin could be found. There was much variation in seed weight and germination behaviour between individual plants within populations. A total of four polymorphic seed categories were observed. The proportions of seeds in the two main categories varied widely between and within populations, and were affected by certain environmental factors. These factors also appeared to affect the degree of inter‐plant variation in seed shape and germination behaviour.Travaux sur les espàes indésirables du genre Polygonum L. V. Variations dans le poids des semences, leur comportement à la germination et leur polymorphisme chez P. persic

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01388.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Summary.This project was designed to study various aspects of wild oat competition in spring wheat and flax. From ten to forty wild oat plants/yd2were sufficient to cause significant yield reductions in wheat when grown on summerfallow land or when ammonium phosphate fertilizer was added to stubble land. However, when wheat was grown on stubble land without the benefit of a fertilizer treatment, seventy to one hundred wild oat plants/yd2were needed to suppress wheat yields significantly. This would suggest that on stubble land, soil fertility was a more important factor than moderate densities of wild oats in determining eventual crop yields. In these experiments, wild oats reduced the number of tillers per plant, but did not significantly affect the protein content of the harvested grain.Only ten wild oat plants/yd2were sufficient to reduce flax yields significantly on both summerfallow and stubble land. The only exception was in 1966, when flax grown on summerfallow land was not significantly affected until the density of wild oats reached forty plants/yd2. This confirms the general observation that flax is a poor competitor with wild oats.The results suggest that wild oat competition had already commenced prior to emergence of wheat, particularly with the higher densities of wild oats. In general, competitive effects increased with time and with wild oat density. In flax, severe competition had already taken place prior to the 2–3‐Ieaf stage of the weed in 1964, but did not become severe until after the 2–3‐leaf stage of wild oat growth in 1965 and 1966. Again, competitive effects increased with time and with wild oat density.Results of a final series of experiments, suggested that the optimum seeding date for flax in Manitoba is the latter part of May or the first week of June. Yield reductions due to wild oat competition became very severe as seeding dates were delayed.La compétition de la folle avoine (A vena fatua L.) avec le blé

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01389.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1967.tb01390.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY