ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00330.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.The effects of several herbicides on the rates of CO2uptake and transpiration of intact plants were measured. A simple technique is described which reveals whether photosynthesis‐inhibiting herbicides are inactivated by plants. By this method, the inactivation of simazine by maize could be confirmed. Evidence is presented for physiological inactivation of monuron byPlantago lanceolata, of cycluron (OMU) and pyrazon by sugar beet, of N'‐(4‐butoxyphenyl)‐NN‐dimethylurea by of 5‐bromo‐6‐methyl‐3‐phenyluracil by flax. Certain plant species showed different reactions to some other new herbicides. The effect of herbicides in the culture solution on CO2uptake by the leaves is probably largely determined by the rate of transpiration of the plants. Assuming that uptake in proportional to transpiration rate, estimates of the concentration of the herbicides inside the plant were made.L'inactivation physiologique de quelques herbicides produisant une inhibition

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00331.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.The absorption of urea and a number of its derivatives by different soils was investigated using a slurry‐type procedure. The materials could be listed in the following order of increasing tendancy to be adsorbed: urea, fenuron, methylurea, phenylurea, monuron, monolinuron, diuron. linuron, neburon and chloroxuron. BothN‐aryl andN‐alkyl substituents appeared to play a part in adsorption. Increasing chain length in the alkyl substituents and chloro‐ and chlorophenoxy substitution in the aryl substituent increased adsorption. There was no relationship between adsorption and water solubility.Organic matter content was the only soil property that could be related to adsorptive capacity. The evidence of Langmuir isothermal equilibrium plots suggests that only a fraction of the total soil surface is available for the adsorption of substituted ureas.L'adsorption Je l'uré de ses dérivés sur dff

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00332.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.A series of adsorption experiments was carried out in order to determine if there was significant competition for adsorption sites between diuron and water. Adsorption of diuron was much lower on hydrophilic materials such as cellulose, chitin, aluminium oxide and a soil mineral fraction than on the less hydrophilic ion exchange resins, lignin, carbon and a soil organic fraction. Methylation with methanolic HCL or diazomethane increased adsorption by the soil organic material, but methylation with dimethyl sulphate did not.The soil mineral fraction adsorbed considerably more diuron from petroleum spirit solution than from aqueous solution, but the organic matter preparation adsorbed more from aqueous than from petroleum solution.It was concluded that there is competition between water and diuron for adsorption sites and that diuron is a more effective competitor at soil organic matter surfaces than at soil mineral matter surfaces.Observations sur la relation entre l'adsorption du diuron el la nature de l'adsorbant

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00333.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.Studies were conducted to determine the effect of soil placement of EPTC, di‐allate and propham (IPC) on oats. A technique called the‘envelope method’was used to make possible the separate exposure of coleoptiles, seed and roots of emerging oat seedlings to the various herbicides. EPTC at 1.0 ppm, di‐allate at 2.0 ppm and propham at 3.0 ppm were all extremely toxic to oats through colcoptile uptake. Penetration of roots into treated soil, however, resulted in very little injury to the plant. Plants grew undamaged from seeds which had been allowed to imbibe for 36 hr in soil treated with EPTC at 1.0 ppm.Studies using radioactive EPTC indicated that both roots and coleoptiles readily absorbed EPTC from soil and that measurable amounts translocated both upward and downward. Under certain circumstances, as much unmetabolized EPTC could accumulate in roots as in shoots, even though less toxicity was noted from root exposure. This would indicate, that the differential sensitivity between roots and shoots is not due to differences in uptake, translocation, or metabolic breakdown. Rather it appears that the shoot is the major site of lethal action of EPTC in oats.Étude du placement de l'EPTC et d'autres carbamates dans le sol avecAve

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00334.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.The widespread pentaploid variety of the important weed,Oxalis pes‐capraewas harvested eight times throughout its life cycle. Dry weight and oxalate (acid‐soluble and water‐soluble analyses were made on all parts of the plant at each harvest.From the dry weight data obtained, attention is drawn to three stages during the growth of the plant — namely, the stage of old bulb exhaustion, the time when flowers and new bulbs begin to appear and the onset of senescence. Corresponding with these stages marked changes in oxalate metabolism and/or transport are observed.It is proposed that the stage of old bulb exhaustion would be the most promising at which lo attempt control of the weed by cultivation.Recherches surOxalis pes‐CapraeL. en Australie. I. Études quantitatives de l'acide oxalique durant le cycle vital de la variét

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00335.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.Experiments are described in which appreciable reductions in bulbs of the widespread pentaploid variety ofOxalis pes‐capraeL. were obtained by two cultivations, one at the time of old bulb exhaustion (late May to mid June) and the other in late July or early August. The second cultivation was required to kill plants regenerated from the stems and crowns of plants injured at the first cultivation and was timed to take place before the appearance of new bulbs.Where heavy infestations had been lowered by such cultivations, it proved possible to reduce bulbs still further to very low levels (140 or less kg/ha), acceptable for long‐term control, by spraying with fenoprop (2.2 kg/ha) in the following year. The use of fenoprop alone without previous cultivation and of cultivation alone without subsequent spraying was inadequate except on less severe infestations on light soils.Études sur l'Oxalis pes‐capraeL. en Australie. II. Méthodes de lutte contre la variété p

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00336.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.Achenes ofChenopodium albumare polymorphic; four categories can be recognized visually, brown‐smooth, brown‐reticulate, black‐smooth and black‐reticulate. All four types may be borne by one plant. The polymorphic seeds differ in germination requirements, responding differently to chilling and nitrate application.Dormant seeds contain at least one extractable germination inhibitor. The inhibitor fails to act in the presence of added nitrate.Nitrate is replaceable by some other nitrogen compounds and by chlorate. Nitrate application stimulates germination ofC. albumin soil.The ecological significance of seed polymorphism and the relevance of polymorphism to the interpretation of germination tests are briefly di

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00337.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.The doses required to give 90% control of three weed species have been estimated at different intervals after spraying for four herbicides: amitrole‐T, dalapon‐sodium, disodium mcthylarsonate (DMA) and paraquat. Using the point quadrat method, both first and total contact data showedOttochloa nodosa, to be more tolerant to the herbicides thanPaspalum conjugatum, which in turn was more tolerant thanAxonopus compressus. Ottachloa nodosawas most susceptible to paraquat up to 6 weeks after spraying, but thereafter dalapon was more effective than either paraquat, amitrolc‐T or DMA. ForPaspalum conjugatumfirst contact data showed that paraquat was more effective than amitrole‐T, particularly in the first 10–11 weeks after spraying, and that both were more effective than DMA and dalapon; total contact data showed that paraquat and DMA were the most effective chemicals for up to 6 weeks after spraying but that thereafter amitrole‐T gave best results. Paraquat was the most effective herbicide againstAxonopus compressus, while dalapon was more effective than amitro

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00338.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Summary.Since 1961 the Weed Research Organization has been testing and developing herbicides for weed control in potatoes. Inthe three experiments which are reported, herbicides were compared with other forms of weed control. The first experimentin 1961 was exploratory and compared yields following hand‐weeding versus no weed control versus several promising herbicides. The highest yield was produced by the hand‐weeded crop. Several herbicide treatments applied before crop emergence gave useful selective weed control.Assuming weed control to be necessary, selected herbicides were then compared in 1962 and 1963 with conventional mechanical cultivations. In both years successful weed control by herbicide resulted in a higher yield of potatoes than did mechanical cultivation although the soil‐acting chemical used in 1962 caused some crop damage. The 1963 experiment included triangular planting patterns, at normal and high plant densities. Increases both in gross and marketable yield were obtained at normal plant density with the triangular arrangement as compared with the row crop. The high plant population resulted in the largest gross yield but a lower yield per plant and smaller average tuber

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1965.tb00339.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY