bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethylene and IAA transport in potato
Authors: Hillman J. R. , Fairhurst Valerie 
Published: February 2008

ABSTRACTIt has been suggested that the regulation of plant growth by ethylene may involve modification of IAA transport. We have examined this theory and an account will be given of the effects of ethylene on lateral and longitudinal IAA transport in potato sprouts and stolons. The techniques employed included microautoradiography and a new micropipette injection system.
Ethylene and water stress
Authors: Hall M. A. 
Published: February 2008

ABSTRACTLike some other growth regulators, internal ethylene levels in plants fluctuate as a consequence of water stress and this phenomenon may be responsible for some of the developmental responses which result. Current work seeks to determine how internal ethylene levels are controlled, i.e. by biosynthesis, translocation, diffusion out of the plant or metabolism. The levels of other growth regulators in the same tissue are also being investigated in relation to the changes in internal ethylene.
The composition of the soil atmosphere in a barley mono‐cropping situation with and without tillage
Authors: Bell Margaret J. R. , Holmes J. C. 
Published: February 2008

ABSTRACTWeekly gas samples from two depths in a long term experiment were analysed in 1973 and 1974 for carbon dioxide, oxygen, nitrogen, methane and ethylene. An attempt will be made to relate the varying concentrations to soil series, soil moisture, rainfall and temperature. Ethylene has been detected on several occasions.
Ethylene pollution in the atmosphere
Authors: George E. F. , Clark J. Gordon 
Published: February 2008

ABSTRACTPlants demonstrate various responses when subjected to relatively low concentrations of ethylene gas in the ambient air. The duration of exposure required depends on concentration and varies in different plants and according to stage and manner of growth. Several external factors may also influence the response of intact plants.Besides emissions from industrial installations, ethylene is produced externally from many natural sources and in consequence of human activities. The bulk of evidence suggests that ethylene is not at present a serious pollutant but we suggest that further and more precise research is required.
Commercial uses of ethephon in crop production
Authors: Sterry J. R. 
Published: February 2008

ABSTRACTSince its discovery in 1966, 2‐chloroethylphosphonic acid, with a proposed common chemical name of ethephon (EthrelE) has been increasingly utilized in a number of important crops, including latex stimulation of rubber (Hevea brasiliensis), acceleration of maturity and/or abscission of many fruits and nuts and modification of growth characteristics of various food and fibre crops. It can be an important aid to programmed production, mechanical harvesting and enhancement of quality. Continuing experimentation is still finding new potential uses.
The involvement of ethylene in vascular wilt diseases
Authors: Pegg G. F. 
Published: February 2008

ABSTRACTPlants exhibiting a wilt syndrome induced by the vascular pathogens Verticillium albo‐atrum or Pseudomonas solanacearum produce increased amounts of ethylene which may or may not include a contribution from the pathogen.Resistant, infected tomato plants do not produce more ethylene in the absence of visible symptoms. Ethylene is produced rapidly in affected susceptible plants as symptoms appear suggesting a tissue wound response. No correlation could be demonstrated between ethylene evolution and loss of leaf turgor or stomatal density. Many of the symptoms of vascular wilt infection may be reproduced by ethylene. This suggests that ethylene functions as a phyto‐toxin. Gassing inoculated plants with ethylene may, however, protect against symptom development. A multiple role for ethylene involvement in pathogenesis is discussed in relation to host hydrolase activity.
Simulation of the hop Verticillium wilt syndrome by applications of ethrel
Authors: Talboys P. W. 
Published: February 2008

ABSTRACTSome of the diverse range of leaf symptoms of hop wilt can be induced simply by introducing solutions of ethephon at pH 6‐4 into the vascular system; others require the additional presence of a larger molecule, which can be ‘modelled’ by a polyethylene glycol. Treatments which include ethephon cause enlargement of cells associated with the vascular elements, resulting in tylosis and other anatomical changes similar to those found in Verticillium‐infected plants.
Epidemiology of damping‐off disease (Pythium irregulare) in relation to density of Lepidium sativum seedlings
Authors: BURDON J. J. , CHILVERS G. A. 
Published: February 2008

SUMMARYControlled experiments on post‐emergence damping‐off, using small populations of garden cress seedlings (Lepidium sativum) inoculated with Pythium irregulare, demonstrate that planting density of the host population plays an important role in determining the rate of multiplication and the rate of advance of the disease. At high seedling densities the disease is transmitted readily between host plants, but at lower densities the greater distance between adjacent plants reduces the probability of successful transmissions, and this is reflected in the parameters of multiplication and advance. A simple negative relationship was found between the mean distance separating adjacent plants and both rate of advance of disease front and rate of multiplication of disease in a randomly inoculated seedling stand.
Decrease of take‐all by a transmissible factor in take‐all decline soils
Authors: POPE A. M. S. , HORNBY D. 
Published: February 2008

SUMMARYIrrespective of type and cropping history, soils with take‐all decline (D soils) contained a take‐all‐decreasing factor that could be transmitted to cereal soils in which take‐all had not declined (U soils). As little as 0.001 % by weight of D soil decreased take‐all by 50 % in some seedling assays, but in a longer, outdoor test the decrease proved to be temporary and within 10 wk disease increased to equal that in unamended U soil. In two tests in which D soil was amended with U soil there was an unexpected increase in disease in seedling assays. Particulate fractions (0.2‐2.0 μm) from leachates of D soils, but not the coarse fractions (> 1 mm, dry sieved; > 150μm, wet sieved) of these soils, decreased disease in assays. Although moved downwards by water, the transmissible factor in D soil did not spread laterally into adjacent unamended U soil and D soil amendments of U soil were most effective as top dressings and least effective when initially placed below assay seedlings. D soil was slightly less effective when added 14 days after planting wheat in U soil, but incubating soil mixtures for up to 4 wk before planting gave variable results, although there was always some decrease in take‐all. The transmissible factor could be eliminated by heating moist soil for 30 min at 70 oC (but not 60 oC). The evidence suggests that the factor is biological, but is insufficient to suggest that it is the cause of take‐all decline.
The use of weather data and counts of aphids in the field to predict the incidence of yellowing viruses of sugar‐beet crops in England in relation to the use of insecticides
Authors: WATSON MARION A. , HEATHCOTE G. D. , LAUCKNER F. B. , SOWRAY P. ANNE 
Published: February 2008

SUMMARYPartial regression equations were calculated that relate the mean percentage of plants infected with yellowing viruses (beet yellows and beet mild yellowing viruses) in sugar‐beet crops at the end of August to the number of days during January, February and March when temperatures fell below – 0.3 °C (31‐5 °F) and the mean temperatures in April, for the 21 yr, 1951–71, using weather records from Rothamsted Experimental Station. Regression analyses were also made to find the effect of other factors including mean and minimum temperatures for the same months, and also mean counts of ‘green aphids’, mainly of the vector Myzus persicae, on sugar‐beet plants during May and June. Significant relationships were established with all factors, but ‘frost‐days’ and April mean temperatures accounted for the greatest percentage of the variance in yellows incidence.The calculations were made separately for the years from 1951 to 1958, when no routine advice was given to farmers about aphid control, and 1959–71 when a ‘spray‐warning scheme’ was in operation, and many crops were sprayed at critical times to prevent aphid‐ and virus‐spread. Weather factors had the same effects in both periods, but for any particular weather less virus was spread in the second period than in the first, although there were sufficient aphids, i.e. the numbers expected from the prevailing weather conditions. There was no evidence that insecticide treatment used in any one year affected aphid‐incidence in subsequent years.Regression analyses on weather variables were also calculated separately for each of seventeen beet‐sugar factory collection‐areas, using weather records from local weather stations, and also the Rothamsted weather records. Unexpectedly, the fit of the regressions was always better with Rothamsted weather data than with local weather records. Mean yellows‐incidence for the different factory areas declined from south to north, and there was a linear relationship with the square root of the latitude above 50 °C. At the same time the correlation coefficients relating yellows‐incidence to ‘frost‐days’ became smaller and less significant, and those showing dependence
Some effects of oxamyl on the virus‐vector nematodes Longidorus elongatus and Xiphinema diversicaudatutn
Authors: FORER L. B. , TRUDGILL D. L. , ALPHEY T. J. W. 
Published: February 2008

SUMMARYOxamyl applied to field soil prevented Longidorus elongatus from acquiring and transmitting tomato black ring virus for at least 6 wk, although numbers of nematodes were not greatly decreased compared with the untreated control. Glasshouse and laboratory tests examined the effects of oxamyl on viruliferous L. elongatus and Xiphinema diversicaudatum. In these tests oxamyl (1.0 ppm) in the soil water largely prevented L. elongatus transmitting virus to bait plants over a period of 1 month. X. diversicaudatum was equally affected by smaller concentrations, 0.1 ppm being sufficient to inhibit virus transmission in one test. Inhibition of virus transmission was associated with a decrease in the number of root tip galls produced by nematode feeding, especially that of X. diversicaudatum. Few nematodes were seriously affected by oxamyl, except at the greatest concentration tested (100 ppm), when numbers of L. elongatus, but not of X. diversicaudatum, were decreased. In vitro‐treated viruliferous nematodes protracted their stylets, but their subsequent ability to transmit virus was unimpaired.
Common and newly‐recorded forage crop diseases in Ireland
Authors: O'ROURKE C. J. 
Published: February 2008

SUMMARYSurveys of forage crop diseases in the Republic of Ireland have been conducted annually since 1965. Over fifty fungal diseases have been noted, about half of which are of likely economic importance. Disease control investigations were carried out on the more prevalent diseases, such as crown rust and Ophiobolus patch of ryegrass, leaf fleck of cocksfoot and powdery mildew of tall fescue. Some pathogens previously unrecorded in the British Isles were found. These included Spermospora lolii and Lolium mottle virus on ryegrass, and Mastigosporium kitzebergense on timothy.
Surveys of pest incidence on oil‐seed rape in south central England
Authors: GOULD H. J. 
Published: February 2008

SUMMARYSurveys of pest incidence on oil‐seed rape in the south of England in 6 yr have shown that Meligethes aeneus can cause a considerable loss of pods on some fields. There is some evidence that control measures are often applied too late to obtain the best results; preliminary observations on the probable effect on yield are also presented. Ceuthorhynchus assimilis was recorded on the majority of fields with an average of 19% pods infested on spring‐sown rape. Very heavy pod infestations were found on farms where rape had been grown regularly for some years. Dasyneura brassicae is at present not an important pest with an average of less than 1% pods infested. However, in each year infestations of up to 11% pod attack were recorded on a few fields.
The nature of the effects of the aphids Sitobion avenae and Metopolophium dirhodum on the growth of wheat
Authors: WRATTEN S. D. 
Published: February 2008

SUMMARYField‐caged, post‐anthesis populations of the aphids Sitobion avenae and Metopolophium dirhodum reduced grain weight of wheat by 14 and 7% respectively and induced changes in the senescence of the flag leaf. Spikelet number and grain number were unaffected as they are normally determined by pre‐anthesis factors. Percentage grain protein was significantly reduced by both aphid species.The pattern of grain weight reduction within the ear was consistent with known limitations on the distribution of flag leaf assimilates among the grains. The relative effects of the two aphid species apparently resulted from the degree of nutrient drain imposed at particular feeding sites and the reduction in the leaf area duration of the flag leaf.
The control of wet bubble disease of mushrooms caused by Mycogone perniciosa
Authors: FLETCHER J. T. , DRAKES G. D. , TALENT C. J. W. 
Published: February 2008

SUMMARYIn experiments on the control of Mycogone perniciosa there was a good relationship between yield, disease incidence and the rate of benomyl applied to the casing. Casing treatment controlled the disease irrespective of time of inoculation. Benomyl controlled the disease in all experiments and good results were also achieved with thiophanate methyl and to a lesser extent with thiabendazole. Bioassay of sporophores showed the presence of an inhibitory substance from benomyl and thiophanate methyl treatments even after 6 wk of cropping.
Soil‐borne viruses occurring in nursery soils and infecting some ornamental species of Rosaceae
Authors: SWEET J. B. 
Published: February 2008

SUMMARYSoil from twelve of twenty‐six sites on ten nurseries growing ornamental trees and shrubs contained viruliferous nematodes, transmitting arabis mosaic virus (AMV) at eight sites, tomato black ring virus at three and tobacco rattle virus at one site. Tobacco necrosis virus was detected at two sites. Xiphinema spp. were found at nine sites, Longidorus spp. at sixteen and Trichodorus spp. at thirteen sites. Thirty‐one ornamental species of Rosaceae were tested for virus infections and AMV was found in Spiraea bumalda, Spiraea japonica alba and Kerria japonica.
Effects of defoliation on growth and yield in groundnut (Arachis hypogea), cowpeas (Vigna unguiculata), soyabean (Glycine max) and green gram (Vigna aurens)
Authors: ENYI B. A. C. 
Published: February 2008

SUMMARYDefoliation reduced the dry weight of stems, pods, grains and size of individual grains in all four of the legume crops studied and the dry weight of flowering inflorescence stalk in the case of cowpeas and green gram only. The adverse effect of defoliation was more pronounced when defoliation was complete than when half of the number of leaves were removed. The greatest reduction in grain yield occurred when the plants were defoliated during the early podding stage, the percentage reduction being 59.7, 79.0, 86.4 and 95.3 in groundnut, cowpeas, soyabeans and green gram respectively when completely defoliated at this stage and 43.3, 14.0, 42.4 and 46.1 respectively when only half defoliated. The results show that assimilates produced by the leaves during the early stages of growth are used in the growth of stems and leaves, but the assimilates produced during the reproductive stage are used mainly for the growth of the pods. In groundnut, pod number and grain weight were positively correlated with stem weight. It appears that defoliation reduced pod number by depressing the growth of stems and this in turn reduced the number of flowering nodes.The reasons for the differences between the crops in their response to the defoliation treatments and the practical implications of the findings in relation to pest and disease control and plucking of leaves for human consumption are discussed.
Stomatal diffusion resistances and leaf growth during droughting of Lolium perenne plants selected for contrasting epidermal ridging
Authors: WILSON D. 
Published: February 2008

SUMMARYGroups of Lolium perenne plants selected for either deep or shallow adaxial epidermal ridging were grown in a 16 h day of 70 W m‐2 at 25°C, and either watered daily to 33% or allowed to dry to and then watered daily to 21% or to 16% soil moisture. During a 9 day experimental period, adaxial leaf resistances (r1) were measured with a diffusion porometer four times daily, transpiration was estimated gravimetrically, and daily rates of leaf extension were recorded.Measurements were also made of minimum abaxial resistances, stomatal frequencies and lengths, and relative leaf water content (RLWC). At 33%, 21% or 16% soil moisture, leaf extension rates of deep ridged leaves were, respectively, slower, the same, and more rapid than those with shallow ridges. At 21% or 16% soil moisture, the adaxial rl of deep‐ridged was much lower than that of shallow‐ridged leaves at all four sampling times. This difference was most marked on leaves below the youngest fully expanded, and was observed among older leaves even when plants were well watered. At low RLWC (< 85%), leaf resistance was greatest in leaves with shallow ridges. There was no significant difference between the leaf types in the calculated contributions of stomatal frequency or of morphology at any one pore opening, to rl but deep‐ridged leaves had more stomataonthe abaxial surface. Daily rate of plant water loss was directly correlated (r=+ 0.86, P < 0.01) with mean daily maximum stomatal conductance (1/rl), and rate of leaf extension negatively with maximum rl. It is suggested that stomata operating in the concavity formed by deep ridges open wider and are less responsive to internal changes in, for example, leaf water status, than those on shallow‐ridged leaves because of a more humid microenvironment at the epidermal surface. The results are discussed in relation to the concept of ‘water‐savers’ and ‘water‐spenders’ and its application to breeding for dry conditions.
Effect of European wheat striate mosaic, acquired transovarially, on the biology of its planthopper vector Javesella pellucida
Authors: AMMAR E.‐D. 
Published: February 2008

SUMMARYThe proportion of infective nymphs of Javesella pellucida in the progenies of female vectors of European wheat striate mosaic (EWSM) disease ranged from 85 to 96%; 71% of these nymphs infected plants within one week of hatching. Inbreeding for one or two generations significantly decreased the viability of J. pellucida eggs, but EWSM had no effect on the viability of eggs laid by inbred or outbred vector lines. However, EWSM acquired transovarially usually increased the mortality of J. pellucida nymphs by 13 to 17%, although mortality was as high as 30% in some vector lines. EWSM, acquired transovarially for two generations, decreased the longevity of adult males and females of J. pellucida by 14%. Inbreeding for two generations resulted in 40% increase in the mortality of nymphs and more than 50% reduction in the longevity of adults.
Polyacrylic acid‐induced resistance to tobacco mosaic virus in tobacco cv. Xanthi
Authors: KASSANIS B. , WHITE R. F. 
Published: February 2008

SUMMARYPolyacrylic acid (PA) of molecular weight 1700A, 1700B and 3500 caused resistance to infection with tobacco mosaic virus in tobacco cv. Xanthi‐nc, when sprayed on the leaves or watered into the soil. The numbers of lesions produced in the treated plants were between 27 and 97% fewer than in the untreated plants depending on the concentration of PA, its molecular weight and the method of application. Some resistance was caused against potato virus X and potato virus Y but only at concentrations that were harmful to the plants. It appears that PA activates a mechanism responsible for localizing viruses in hypersensitive plants.
Observations on the toxic effects of organo‐mercury treatments on sugar‐beet seed
Authors: BYFORD W. J. 
Published: February 2008

SUMMARYThe toxicity of organo‐mercury fungicides to sugar‐beet seed increased with the amount added and with the moisture content of the seed. Methyl mercury dicyandiamide was more phytotoxic than the less volatile ethyl and phenyl mercury compounds tested. In a bioassay for organo‐mercury fungicides on seeds, the area of inhibition decreased when moist treated seed was stored in airtight containers.
Numbers of mononchid nematodes in soils sown to cereals and grasses
Authors: NELMES A. J. , McCULLOCH JANET S. 
Published: February 2008

SUMMARYThe distribution of mononchid nematodes Mylonchulus sigmaturus, Mylonchulus brachyuris, Clarkus papillatus, Prionchulus punctatus and Anatonchus tridentatus found in grassland and arable soils in England were studied.Mononchid nematode populations in excess of 5% of the total soil nematode population and in biomass more than 2% of the total soil nematode population were rare. No relationship was found between numbers of mononchids and those of other soil nematodes.In soils sown to spring barley there was no difference in the total numbers of female M. sigmaturus, C. papillatus or A. tridentatus found throughout the year. Juveniles of C. papillatus were most common while those of M. sigmaturus were least common. In grass leys and arable soil P. punctatus numbers were extremely low.Neither phorate nor oxamyl applied at 1.12 kg a.i./ha in March affected mononchid numbers. Although oxamyl at 11.2 kg a.i./ha did not affect the adult female numbers, the numbers of juvenile mononchids were reduced by 38% and 50% in June and November respectively.
Potato tuber lenticels: susceptibility to infection by Erwinia carotovora var. atroseptica and Phytophthora infestans
Authors: ADAMS M. J. 
Published: February 2008

SUMMARYIn laboratory tests, proliferation increased the susceptibility of lenticels on mature tubers to infection by Erwinia carotovora var. atroseptica. No differences in susceptibility to E. c. atroseptica and Phytophthora infestans were detected on tubers lifted at different stages of growth from soil kept wet or dry for 3 wk prior to each sampling. As tubers aged, fewer lenticels became infected by either pathogen or were penetrated by fluorescein dye, presumably because cells had been suberized and cork barriers formed.
Investigations on fungicides
Authors: CARTER G. A. , CHAMBERLAIN K. , WAIN R. L. 
Published: February 2008

SUMMARYThe systemic anti‐mildew activity shown by homologous series of alkoxy‐, alkylamino‐ and alkylthio‐trichloroethyl formamides when applied to the roots of wheat or cucumber seedlings has been measured. In general the thio compounds were much less active than their oxy and amino analogues. The alkyl grouping giving most activity varied from one series to another and with test method. In cucumber plants the most prolonged protection against mildew was given by the sec‐butoxy and sec‐butylamino compounds. When inoculated disks of cucumber leaf tissue were floated upon solutions of the compounds, smaller differences in anti‐mildew activity were found than when application was made through the roots.
Field investigations on the control of club root of cabbage in SriLanka
Authors: WIMALAJEEWA D. L. S. 
Published: February 2008

SUMMARYFive fungicides and two fumigants were tested in five trials against the club root disease of cabbage. Methyl bromide provided the best control of the disease. Quintozene also gave satisfactory results, and its phytotoxic effects could be avoided or minimized by applying it at least 5–6 wk before seeding or transplanting.The use of hydrated lime gave relatively poor control of club root, but, either alone or in combination with fungicides, it improved the growth and establishment of seedlings and transplants. It was concluded that quintozene used in combination with hydrated lime provided an effective and practical means of controlling the disease.