摘要:

Summary.Phytotoxic residues were recorded on soil surfaces sprayed with paraquat (1,1′‐dimethyl‐4,4′‐bipyridylium‐2A) at 1 and 2 Ib/ac a.i. Phytotoxicity was greater on organic than on mineral soils though on both the residues persisted unchanged for at least 14 days and were greater with the higher dose.Germination ofBrassica napusL. was only slightly affected and most seedlings did not show phytotoxic symptoms until after cotyledon expansion. The cotyledons ofTrifolium repensL. showed symptoms on emergence from the testa. By contrast, grains ofLolium perenneL. either failed to germinate on paraquat‐treated soils or showed reduced germination.Seedlings ofT. repenswere susceptible; both root and shoot systems were affected as they grew through layers of soil previously treated with paraquat. Ground limestone appeared to reduce the phytotoxicity of paraquat under some circumstances. Phytotoxic residues were not reduced by surface irrigation but disappeared if the soil surface was disturbed

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00969.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.The morphology ofRumex crispusL.,R. obtusifoliusL. and putative hybrids was examined. There appeared to be evidence of introgressive hybridization, particularly with backcrossing toR. crispus.Seed germination in plants from a mixed population varied widely, but when plotted against the hybrid index for the parent plants the could be partially separated in respect of germination behaviour. Some of the polymorphism previously described may have resulted from inclusion in the tests, together with pure parental types, of plants of hybrid origin which had introgressed to such an extent that they were almost indistinguishable from the parent species. The implications of the discussed.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00970.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Spikes oiAgropyron repens(L.) Beauv. were collected from field crops (mostly spring barley and winter wheat) in England and Wales near the time of crop harvest. Seeds per spike were counted and their germination tested in soil in the glasshouse.About 95% of the samples contained viable seeds; about one third of the samples had fewer than 5 viable seeds/spike, a third between 6 and 15 and a third more than 15. The average number of viable seeds/spike for all samples was 13. Spikes from spring barley (152 samples) had an average of 11 and a maximum of 51 viable seeds and those from winter wheat (42 samples), 20 and 48 respectively. Samples collected within 3 weeks after mid‐July had fewer viable seeds/spike than those collected later. Samples containing morphologically‐different spikes had more viable seeds/spike than apparently uniform samples, and spikes from dense field populations more seeds than those from sparse populati

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00971.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.The herbicide Tordon 50D (picloram + 2,4–D) caused severe shrinkage of the protoplasts of all cells ofPinus radiataneedle segments within 24 h of treatment. Measurements of the resistance of these tissues to low‐frequency and to high‐frequency electrical currents showed a loss in the integrity of the plasmalemma within 4–8 h of treatment. Tordon 22K (picloram) had no such effects. The results with Tordon 50D could be attributed solely to the 2,4‐D content.Both Tordon 50D and Tordon 22K disrupted chloroplast structure in leaf discs, and the integrity of cell membranes in stem tips, ofEucalyptus

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00972.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Seeds of three tobaccoNicotiana tabacumL.) varieties were soaked in water for 0, 1, 3 or 5 days and treated, after sowing in glasshouse flats, withNN‐dimethyl‐αα‐diphenylacetamide (diphenamid) at 4·5 kg/ha 1, 3 or 5 days after sowing or at the cotyledonary stage. Unsprayed series were included as controls. Diphenamid caused thinning of seedlings in all varieties, but one (Maryland Catterton) showed some tolerance. All varieties showed stunting and malformations from diphenamid, particularly when seeds soaked for 5 days were treated either 1 or 5 days afte

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00973.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Granular formulations of several new herbicides were tested for control of weeds in direct‐seeded tropical rice.S‐(4‐chlorobenzyl)‐N N‐diethylthiolcarbamate (benthiocarb) andN‐(butoxymethyl)‐2‐chloro‐2′,6′‐diethylacetanilide (CP 53619) showed a high degree of selectivity between rice and weed seedlings. Applied 6 days after seeding, when grass weeds were at the 1‐2‐leaf stage, both herbicides gave excellent control ofEchinochloa crus‐galliand other weeds, and caused little

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00974.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.A linear increase from 933 to 15,943 ppmw of copper occurred in hydrilla (Hydrilla verticillataCasp.) 4 days after treatment with copper sulphate pentahydrate (CUSO4. 5H2O, CSP) at 0·5–4·0 ppmw of copper. Neither increase in calcium levels to 0·8 MM in the ambient solution nor aeration affected the amount of copper in excised hydrilla tissue during a 24‐h treatment period with CSP at 1·0 ppmw of copper. Part of the accumulated copper appeared to be bound in hydrilla. A higher accumulation of copper occurred after treatment with an organic copper complex (cutrine) than with either CSP or copper chloride (CuCI2.2H2O, at 1·0 ppmw of copper. This high accumulation with cutrine appeared to be related principally to the amount of copper remaining in the treatment

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00975.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.At 2 weeks following application, concentrations of picloram in surface runoff water collected adjacent to a South Texas grassland treated with 1·1 kg/ha ranged from 0·055 to 0·184 ppm as detected by gas chromatography. Picloram in surface runoff water diminished with time and amount of rainfall as a decay function. Picloram was not detectable in a flowing stream 0·8 km below a 32‐ha area treated with 1·1 kg/ha. Residual picloram was not detected in domestic water wells at any time up to 2 years following treatment of adjacent areas with 1·1 kg/ha.Dissipation of picloram from treated livestock‐watering ponds was concentration‐dependent, with the final losses resulting largely from dilution. Initial loss rates in the ponds ranged from 14 to 18%/day but decreased to less than 1%/day at 100 days following treatment. After 100 days, when the concentrations were less than 0·005 ppm, the primary changes in picloram content appeared to be due to dilution from rainfall or to concentration by runoff from adjacent t

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00976.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Summary.Autoradiographs and liquid scintillation counts of cucumber (Cucumis sativusL. cv. Ashley) seedlings indicated rapid absorption and translocation of radioactivity from fluorodifen‐1′‐14C (p‐nitrophenyl‐α,α,α‐trifluoro‐2‐nitro‐p‐tolyl ether labelled with14C in the 1 position of thep‐nitrophenyl ring). After 24 h in 1 mg/1 of fluoro‐difen‐1′‐14C, 25% of the absorbed radioactivity was translocated from the roots.Cucumber seedlings degraded fluorodifen‐1′‐14C via a pathway similar to that reported for peanut seedlings but at a slower rate. The major degradation products werep‐nitrophenol and an unidentified polar compound (Unknown I). More rapid absorption and translocation coupled with slower degradation by cucumber as compared with peanut seedlings are factors which may contribute to the s

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00977.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb00978.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY