摘要:

Summary.A single application of paraquat at 0·56 kg/ha applied in 224 l/ha gave short‐lived control ofMikania cordata.An increase in duration of control was obtained either by increasing the dose from 0·28 kg/ha to 1·12 kg/ha with a constant volume rate (224 l/ha) or by using a constant dose (0·56 kg/ha) and reducing the volume from 896 l/ha to 112 l/ha. Complete eradication ofM. cordatawas achieved by applying paraquat at 0·56 kg/ha or 0·28 kg/ha followed 2‐3 weeks later by a second application at 0·28 kg/ha in 112 l/ha.La lutte contreMikania cordata (Burm. F.)B. L. Robinson dans les cultures au moyen

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00980.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary..Plants ofAgropyron repens(L.) Beauv. which bad been sprayed with N‐(1,1‐dimethylpropynyl)‐3,5‐dichlorobenzamide (pronamide) were examined for changes in external and internal morphology at various times after spraying. Cell enlargement, some necrosis, and an increase in nuclear volume characterized treated rhizome apices. Abnormal metaxylem vessel elements and necrotic phloem were characteristic of the rhizome vascular tissues. Roots showed precocious differentiation and maturation of tissues and eventual vacuolation of the apical maeristem, resulting in complete inhibition of root growth. Nuclei of root meristem cells were much enlarged and contained several nucleoli.Effets duN‐(1,1‐diméthylpropynyl)‐3,5‐dichlorobenzamide sur l'anatomie de l'Agroyron

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00981.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary..Dried subterranean organs ofCynodon dactylon, Cyperus rotundusandSorghum halepensewere incubated in light and heavy soils for 1, 2 or 3 months. After removal of the decayed plant material, the residual bioactivity of the soil was assayed by barley sown directly into the soil and by a barley radicle‐length test on an ethanolic extract of the soil. The two assays gave similar results. In general, the inhibition of growth was proportional to the concentration of plant material in the soil, and was greater in light than in heavy soil. Greater inhibition was caused byC. rotundusandS. halepensethan byC. dactylon.A few instances of growth stimulation were recorde

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00982.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary..Plants ofPolygonum lapathifoliumwere grown either in a glasshouse or outside, at a high or a low level of mineral nutrition, and either with or without competition from barley. The viability and percentage emergence of seedlings from germinated seeds (planted in sterile compost) were higher with seed from glasshouse‐grown plants. High nutrition increased plant weight, seed production and seed weight, and also increased seedling emergence. Competition reduced plant weight, but had only a small, non‐significant, effect on seed production. Seed from plants grown with competition had a greater percentage seedling emergence from germinated se

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00983.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Combinations of copper sulphate pentahydrate (CSP) at 1 0 ppmw of copper with diquat, paraquat, ametryne, atrazine, terbutryne or 2,4‐D at certain concentrations and contact times increased the copper content in hydrilla (Hydrilla verticillataGasp.) in comparison with CSP alone. Combinations of CSP with fenac, dichlobenil, diuron, an amine salt of endothal or dinitrophenol had no effect on copper uptake. CSP plus 1·0 ppmw of ametryne exhibited a synergistic response on hydrilla as determined by dry weight, and was associated with a high concentration of copper. Phosphorus levels in hydrilla were reduced by diquat and paraquat. Hydrilla treated with CSP plus 0·1 ppmw of paraquat contained 32·4% less phosphorus than plants treated with paraquat alone. The phytotoxic effect of certain of these combinations on hydrilla may be due principally to an increased accumulation of copper and a reduction in phosphorus con

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00984.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Measurements were made of the effect of exchangeable cations on the adsorption of linuron and atrazine by an ion‐exchange resin, cellulose phosphate powder, bentonite and a peat soil. The cations studied were Ca2+, Ni2+, Cu2+, Fe3+and Ce4+. The results with linuron were consistent with the hypothesis that complex formation with exchangeable cations is a possible mechanism of adsorption. This was not so with atrazine due to complications arising from pH effects, and it seems unlikely that adsorption of atrazine by this process is significan

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00985.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.An automated colorimetric method has been described for the determination of both total and unchanged herbicide residues of the urea herbicides fluometuron, metobromuron, chlorbromuron and chlortoluron. The method is based on the well‐known Bratton‐Marshall diazotization‐coupling reaction for aromatic amines and is also applicable for other phenylureas as well as for N‐phenylcarbamate and anilide herbicides. The procedure is especially useful when large series of soil samples have to be analysed, for instance in connection with leaching experiments. Manual work and working time have been reduced with this method by up

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00986.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Degradation ofp‐nitrophenyl‐α,α,α:‐trifluoro‐2‐nitro‐p‐tolyl ether (fluorodifen) labelled with14C in the 1 position of thep‐nitrophenyl ring (1′‐14C) proceeded rapidly in peanut (Arachis hypogaeaL. cv. Starr) seedling roots. All degradation products were present after only 2 h.The major degradation products for fluorodifen‐1′‐14C were the water‐soluble compoundsp‐nitrophenol and Unknown I, a polar compound or complex which remained on the origin during thin‐layer chromatography. Minor products includedp‐nitrophenyl‐α,α,α‐trifluoro‐2‐amino‐p‐tolyl ether,p‐aminophenyl‐α,α,α‐trifluoro‐2‐nitro‐p‐tolyl ether and traces ofp‐aminophenol. Nop‐aminophenyl‐α,α,α‐trinuoro‐2‐amino‐p‐tolyl ether was detected. Thep‐aminophenol previously reported [PL Physiol., Lancaster, 44,1397‐1401 (1969)] was notp‐aminophenol, but primarily Unknown I with a possible tr

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00987.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Plants ofChenopodium albumL. were grown at a range of different densities in each of three years. The stem diameter, the number of main branches and the size and number of leaves decreased with increasing density as did weight and leaf area per plant. The dry‐matter yield per unit area increased with density up to 576 plants/m2in two of the three trial years. The proportion of the seed yield relative to the total yield was higher in the leas dense than in the dense stands, or was almost constant. Density did not affect the seed yield per unit area, but seed yield per plant fell as density increased. Maximum seed production was 41 900 per plant and the mean seed yield over the three years was 8300 seeds per plant. The percentages of nitrogen, phosphorus, potassium and calcium were highest when the plants were at an early stage of development. The proportions of these elements in the dry‐matter yield decreased with increasing age of the plants. The density of the stand did not affect the percentages of elements but the total amounts per plot were greatest at the flowering stage and in the denser sta

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00988.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.The relative susceptibility of six commercial sugarcane varieties to diuron previously described was confirmed in a second similar experiment. A significant correlation was found between the susceptibility of these varieties to 10 kg/ha diuron and their rooting characteristics. The more susceptible varieties were found to produce larger sett‐roots and smaller shoot‐roots, both of which also tended to be more easily injured by diuron. The root injury appeared as‘burnt’root tips resulting from contact with the layer of soil treated by the herbicide. The roots of tolerant varieties seemed to be immune to such injury and continued growing after penetrating the contaminated soil layers. Retarded plant growth appeared to result from the root injury.Uptake of diuron through shoot‐roots of the susceptible variety F 156 resulted in 68·5% growth retardation. This damage was reduced by 15·5% if the plants were allowed to develop sett‐roots from two‐bud cutting. Death of the plant resulted when both root systems received the same do

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00989.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY