bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production and characteristics of antisera to Spiroplasma citri and clover phyllody‐associated antigens derived from plants
Authors: CLARK M. F. , BARBARA D. J. , DAVIES D. L. 
Published: February 2008

SUMMARYAntisera were produced to clover phyllody‐ and Spiroplasma citri‐associated antigens partially purified from infected Vinca rosea plants. Separate antisera were made to ‘membrane fraction’ (MF) preparations comprising the resuspended pellet obtained by high speed centrifugation, and to ‘soluble fraction’ (SA) preparations, comprising the supernatant from high speed centrifugation concentrated by freeze‐drying.All antisera showed considerable activity against normal plant antigens but after cross‐absorption with extracts of healthy plants the MF antisera were used in F(ab')2based ELISA tests to detect S. citri‐ or clover phyllody‐associated antigens in infected plants. The ‘clover phyllody’ antiserum also reacted specifically with extracts of clover plants with phyllody, and with naturally‐infected strawberry plants showing symptoms of green petal disease. Both the ‘clover phyllody’ and S. citri antisera were specific for their respective homologous antigens. No cross‐reactions were observed in heterologous tests or between either antiserum and extracts of V. rosea infected with various MLOs obtained from different host plants.
Hydrangea mosaic virus, a new ilarvirus from Hydrangea macrophylla (Saxifragaceae)
Authors: THOMAS B. J. , BARTON R. J. , TUSZYNSKI ANNA 
Published: February 2008

SUMMARYA previously unrecognised virus isolated from Hydrangea macrophylla with chlorotic mosaic leaf symptoms in West Sussex was named hydrangea mosaic virus (HydMV). HydMV was mechanically transmitted without difficulty to four of 16 species from three of five families, and was seed transmitted in Chenopodium quinoa, but was not aphid transmitted.Although relatively unstable in vitro, HydMV was purified by clarifying leaf extracts by emulsification with chloroform and acidification with citric acid, followed by differential centrifugation and sucrose density gradient centrifugation. Purified virus incompletely separated on sucrose density gradients into three components (T. M and B) with sedimentation coefficients (so20w) of 86, 97, and 105 S respectively, but all particles had buoyant densities in caesium chloride of 1.37 g/cm3. Virus contained a single polypeptide species (mol. wt 26.4 times 103), appeared quasiisometric to ovoid or elliptical, and measured c. 28 times 30 (T), 30 times 30 (M) or 30 times 32–38 nm (B). Single‐stranded RNA species or mol. wt 1–25, 1–08, 0–83, 0–36 and 0–27 (RNA‐1 to 5 respectively) were obtained from virus preparations but mixtures containing RNA‐1 to 3 plus either RNA‐4 + 5 or the coat protein, were infective.These properties suggest that HydMV has affinities with ilarviruses, but it showed no serological relationship to any of six ilarviruses or 42 other viruses.
Bromide residues in transplanted brassicas following methyl bromide treatment of seedbed and field
Authors: WHITE J. G. , HUNT J. 
Published: February 2008

SUMMARYMethyl bromide applied to brassica seedbeds resulted in bromide concentrations in cabbage, cauliflower and Brussels sprout transplants of 389‐4‐2082‐3 mg/kg fresh tissue. When the transplants were grown to maturity on untreated field plots bromide concentrations in the plants fell to levels similar to those occurring naturally. Treatment with methyl bromide of both seedbeds and field plots resulted in plant bromide concentrations in cabbage plants of 211‐4 mg/kg, a level in excess of the proposed maximum residue limit of 100 mg/kg fresh matter. Bromide concentrations in the edible portions of cauliflower were between 24‐8 and 96‐0 mg/kg and those in Brussels sprouts between 49‐3 and 121‐3 mg/kg.
Transmission of Fusarium solani var. coeruleum and F. sulphureum from seed potatoes to progeny tubers in the field
Authors: ADAMS M. J. , LAPWOOD D. H. 
Published: February 2008

SUMMARYIn experiments in three years, seed tubers were inoculated before planting with either Fusarium solani var. coeruleum or F. sulphureum to initiate a rot, or were contaminated by dipping in soil slurries containing spore suspensions of one or other of the pathogens. Transmission to progeny tubers was tested by uniformly wounding and incubating tubers and by dilution plating of soil samples.In two years, transmission of F. sulphureum was greater from highly contaminated than from rotting seed and was greater on cv. Pentland Crown than on cvs Desiree and Maris Piper. F. solani var. coeruleum appeared to be transmitted most readily from rotting seed and Maris Piper was the cultivar most extensively contaminated. In experiments with different harvest dates, transmission of both fungi from highly contaminated seed could be detected by late June or mid‐July. More progeny tuber wounds rotted in F. sulphureum than in F. solani var. coeruleum plots and in one year, F. sulphureum caused more rots on cv. Record than on cv. Maris Piper.These differences between the pathogens may be related to their differing abilities to sporulate underground on the surface of seed tubers and on stem bases.
The effect of Rhizobium inoculation and nitrogen fertiliser on nitrogen fixation and seed yield of dry beans (Phaseolus vulgaris)
Authors: TAYLOR J. D. , DAY J. M. , DUDLEY C. L. 
Published: February 2008

SUMMARYThe potential benefit to be derived from seed inoculation of Phaseolus vulgaris beans with effective strains of Rhizobium phaseoli, was investigated in field experiments over three years on a site low in soil nitrogen and lacking indigenous effective strains of R. phaseoli.Inoculation with R. phaseoli (strain RCR 3644) produced significant increases in nodulation, nitrogenase activity and plant growth in all experiments. In trials in 1978 and 1979, with cv. Seafarer, inoculation, in the absence of nitrogen fertiliser doubled seed yields. In 1978, the seed yields from inoculated beans without nitrogen fertiliser (1–6 t/ha) were not significantly different from those obtained with uninoculated beans receiving the optimum nitrogen fertiliser treatment of 120 kg N/ha (1–75 t/ha). In 1979, with lower rainfall favouring more efficient utilisation of nitrogen fertiliser, inoculation gave seed yields (1–88 t/ha) equivalent to those obtained with 60 kg N/ha (1–70 t/ha) but significantly less than with 120 kg N/ha (2–88 t/ha). More precise estimates from nitrogen response curves showed that inoculation supplied the fertiliser equivalent of 105 and 70 kg N/ha in 1978 and 1979 respectively. In both years, significant benefits were also obtained by the combination of inoculation and nitrogen fertiliser.In a separate experiment in 1979, with four R. phaseoli strains inoculated onto eight bean cultivars, three were highly effective nitrogen fixers on all cultivars. Two strains (RCR 3644 and NVRS 963A) each increased mean yields, in the absence of nitrogen fertiliser, from 1–39 t/ha uninoculated to c. 2–5 t/ha inoculated whilst strain RCR 3622 was outstanding with a mean yield of 3‐0 t/ha. An analysis of the nitrogen content of seed showed that gains from nitrogen fixation were 37–57 kg N/ha/growing cycle for the combination RCR 3644 with cv. Seafarer. However, 106 kg N/ha/growing cycle was recorded for the combination RCR 3622 and cv. Aurora.
A satellite‐like nucleic acid of arabis mosaic virus associated with hop nettlehead disease
Authors: DAVIES D. L. , CLARK M. F. 
Published: February 2008

SUMMARYAn isolate of arabis mosaic virus (AMV) from a hop plant with symptoms of nettlehead disease induced unusually severe symptoms when transmitted to Chenopodium quinoa. This isolate, called AMV‐Ta, yielded particle preparations in which up to 80% of the nucleic acids consisted of a species of low molecular weight (SNA), estimated to be about 75 000 daltons by polyacrylamide gel (PAG) electrophoresis.An isolate free of detectable S‐NA (AMV‐To) was derived from AMV‐Ta by inoculating plants with the two high molecular weight genomic RNA species of AMV (2–8 times 106 and 1–3 times 106 daltons; Murant, 1981) separated from S‐NA by PAG electrophoresis. This isolate induced much milder symptoms in C. quinoa. Hop seedlings inoculated with AMV‐Ta, either mechanically or by nematodes, developed characteristic nettlehead symptoms. Hop seedlings similarly inoculated with AMV‐To remained free of nettlehead symptoms.Two species of S‐NA associated with hop nettlehead isolates of AMV were detected at two sites in Kent, and two West Midlands sites. At both sites in Kent and at one of the West Midlands sites, the occurrence of the S‐NA species was closely correlated with the incidence of nettlehead symptoms. At the other site in the West Midlands, the occurrence of nettlehead symptoms was too erratic to allow positive correlation of SNA with symptom development.Our results show that S‐NA plays an active part in symptom production in experimentally inoculated plants of both hops and C. quinoa. In addition, the close correlation between the occurrence of AMV with additional nucleic acid species, and the incidence of nettlehead symptoms in commercially grown hops, suggests a role for S‐NA in the aetiology of this disease.
Efficacy of avermectins against a plant parasitic nematode
Authors: WRIGHT D. J. , BIRTLE A. J. , CORPS A. E. , DYBAS R. A. 
Published: February 2008

SUMMARYAvermectins (AVM) B1a/1b and B2a‐23‐one rapidly impaired the locomotor activity of Meioidogyne incognita second stage juveniles. On agar plates, concentrations as low as 0–0003 μg AVM B2a‐23‐one cm‐3 significantly reduced the number of juveniles in cucumber roots and the proportion of juveniles which developed to a saccate stage. The effects of AVM on hatching and movement of nematodes appeared to be at least partly reversible.
Effect of the nematicide oxamyl on the multiplication of Globodera rostochiensis and G. pallida and on the haulm growth and yield of six potato cultivars with different levels of resistance and tolerance
Authors: TRUDGILL D. L. , HOLLIDAY J. M. , MATHIAS P. L. , FRENCH N. , MACKINTOSH G. M. , TONES S. J. 
Published: February 2008

SUMMARYThe effect of a pre‐planting application of oxamyl on the yields of six potato cultivars was studied in co‐operative field trials in 1981. Two sites were ‘uninfested’ with potato cyst nematodes (PCN), two were lightly infested (<25 eggs/g soil) and six were moderately to heavily infested (three with Globodera rostochiensis and three with G. pallida). At the uninfested and lightly infested sites oxamyl had little effect on mid‐season haulm weights or on final tuber yields. At sites moderately to heavily infested with G. rostochiensis the haulm growth of all cultivars tended to be increased by a similar amount on plots treated with oxamyl, Pentland Dell being least responsive. Yield was increased by different amounts, the increases being least for cvs Cara and Maris Piper and most for Corsair and Pentland Dell. At the sites moderately to heavily infested with G. pallida Cara was again tolerant, its yield being increased little by oxamyl compared with the other cultivars. Maris Piper gave the largest yield increase.Final populations of PCN on non‐resistant cultivars were reduced by oxamyl at some sites but not at others. Resistant cultivars also decreased the final numbers of PCN at most sites. Two cultivars derived from Solanum vernei with different degrees of resistance, appeared to be almost equally effective in controlling G. rostochiensis and G. pallida.
Resistance to raspberry cane midge (Resseliella theobaldi) and its association with wound periderm in Rubus crataegifolius and its red raspberry derivatives
Authors: McNICOL R. J. , WILLIAMSON B. , JENNINGS D. L. , WOODFORD J. A. T. 
Published: February 2008

SUMMARY Rubus parviflorus, R. odoratus and F2 plants from the cross R. crataegifolius x R. idaeus were resistant to the raspberry cane midge (Resseliella theobaldi) when exposed to the pest in an insectary or in the field.Histological studies of R. crataegifolius and one of its hybrids with R. idaeus showed that resistance was associated with a wound periderm of suberised and lignified cells. These cells were formed from the primary cortex and phelloid cells of the polyderm as a rapid response to the occurrence of natural splits and wounds which are the oviposition sites of R. theobaldi. In the hybrid, new tissues from this wound periderm prevented the peeling of the mature primary cortex, thereby precluding serious midge attack, and resulted in a reticulate appearance on the cane surface, a distinctive cane feature useful for identifying resistant segregates.
Callus growth and the effect of wound dressings
Authors: MERCER P. C. 
Published: February 2008

SUMMARYGrowth of callus tissue on tree wounds tended to be greater if wounds were flush, large and treated with a wound dressing, particularly one containing thiophanate methyl, if the trees were young and vigorous or had had an application of fertiliser. Growth of callus also varied with species, but in beech, at least, did not appear to be affected by season of wounding.
Host range and virulence of five baculoviruses from lepidopterous hosts
Authors: ALLAWAY GRAHAM P. , PAYNE CHRISTOPHER C. 
Published: February 2008

SUMMARYThe host range and virulence of five insect baculoviruses (two multiply‐enveloped nuclear polyhedrosis viruses (MNPVs) from Agrotis segetum and Mamestra brassicae; one singly‐enveloped NPV from Plusia gamma and two granulosis viruses (GVs) from A. segetum and Pieris brassicae) were studied for seven lepidopterous pests of temperate agriculture (A. segetum, Agrotis exclamationis, Lacanobia oleracea, M. brassicae, Noctua pronuba, P. gamma and Pieris rapae). None of the viruses killed all species but M. brassicae MNPV failed to infect only P. rapae. The other viruses were restricted to the homologous host, or members of its genus or subfamily. In all examples except A. segetum GV, the median lethal dose for the most susceptible host, was less than 22 virus inclusion bodies and median lethal times for all infections ranged from 5·5 to 16·6 days. The low susceptibility of A. segetum and other noctuids to GV infections is discussed in relation to the structure of inclusion bodies and the nature of the infectious unit in baculoviruses.
Assessment of the frost sensitivity of Trifolium species by chlorophyll fluorescence analysis
Authors: BARNES J.D. , WILSON J.M. 
Published: February 2008

SUMMARYThe potential of the chlorophyll fluorescence technique in screening for frost sensitivity in a range of Trifolium species from different geographical origins was assessed by measuring the decrease in variable chlorophyll fluorescence (Fvar) of leaves after freezing at ‐ 5°C for 60 min. The method was rapid and the results obtained agreed well with a visual assessment of freezing injury carried out after leaves were returned to optimal growth conditions for 72 h. Trifolium alexandrinum (Berseem clover) cv. Tabor originating from Israel was shown to be the most frost sensitive species studied and Trifolium subterraneum (subterranean clover) cv. Mt. Barker, from temperate regions of Australia, the most frost resistant. On extended periods of freezing, frost damage increased and this was associated with a further reduction in variable chlorophyll fluorescence and in quenching capacity of the thylakoid membranes. These results thus indicate that substantial thylakoid membrane dysfunction is induced at freezing temperatures. Furthermore, it was found that frost hardening of the frost sensitive species T. alexandrinum for 21 days at 5°C reduced the extent of damage sustained by the thylakoid membranes as shown by higher fluorescence quenching capacity, smaller reduction in variable fluorescence (Fvar) and higher initial fluorescence (Fo) when leaves of hardened plants were frozen at ‐5°C and ‐7°C.
Nitrogen fertilisation and light effects on growth and photosynthesis of lodgepole pine seedlings
Authors: EKWEBELAM S.A. , REID C.P.P. 
Published: February 2008

SUMMARYSeedlings of Pinus contorta were grown for 16 wk without ectomycorrhizas in the greenhouse at three levels of irradiance (100, 210 and 470 μEm‐2s‐1) and three levels of ammonium nitrate (3, 62 and 248 mg litre‐1 of N). Measurements at 5, 10 and 16 wk of age indicated that plants receiving the highest levels of irradiance and nitrogen had significantly larger biomass, a higher total foliar N and P content and net photosynthesis per unit leaf area than those at lower levels of each factor. Although the root/shoot ratio also increased from low to high irradiance at each harvest, nitrogen application resulted in an increased ratio from 3 to 62 mg litre‐1 N, but decreased ratio at 248 mg litre‐1 N.
Phenolic acids associated with the resistance of lettuce cultivars to the lettuce root aphid
Authors: COLE ROSEMARY A. 
Published: February 2008

SUMMARYPhenolic acids, particularly caffeoylquinic acids, in lettuce root extracts were analysed by high pressure liquid chromatography (hplc), gas liquid chromatography (glc) and ultra‐violet (uv) absorbance to seek a relationship with the resistance of certain lettuce cultivars to lettuce root aphid, Pemphigus bursarius. Although consistent results were obtained by each method, glc estimates of isochlorogenic acid tended to be low and uv estimates high. Hplc results were intermediate and since it was the easiest technique to perform routinely it was preferred.Isochlorogenic acid was the only caffeoylquinic acid detected in quantity and there were greater concentrations in resistant than in susceptible cultivars. Phenylalanine‐ammonia lyase (PAL), the first enzyme in the phenyl propanoid pathway, is more active in resistant cultivars. Although these cultivars also had a greater tendency to browning when damaged, it was not due to greater polyphenol oxidase activity but probably to the presence of more isochlorogenic acid substrate.The results were consistent with an association between isochlorogenic acid concentration, PAL activity and resistance to P. bursarius.
Variation in seedling susceptibility to Bremia lactucae (lettuce downy mildew) in the absence of effective major resistance genes
Authors: NORWOOD JUDITH M. , CRUTE I. R. , PHELPS KATHLEEN 
Published: February 2008

SUMMARYIn the absence of effective major genes the importance of interactions between cultivar genotype, isolate genotype and environment was investigated in experiments using seedlings of eight lettuce cultivars inoculated with three isolates of Bremia lactucae and grown under a number of different environmental conditions. The outcome of the cultivar‐isolate association was measured using four criteria and the data were examined by analysis of variance and correlation. The relative susceptibility of cultivars was generally independent of environment and there was no evidence that isolates were adapted to particular cultivars. Although significant cultivar X isolate interactions were found in individual experiments they were not consistent between experiments, even where these were conducted under apparently identical conditions. Variation resulted from either cultivar X environment or isolate X environment interaction with the environment always the dominant variable.
The relationship between populations of stem‐boring Dipterous larvae in leys and damage to subsequent winter wheat crops
Authors: FRENCH N. , NICHOLS D. B. R. 
Published: February 2008

SUMMARYDuring September of each year from 1978‐82, dipterous stem‐boring larval populations were assessed in 28–35 grass fields in northern England before they were ploughed and sown with winter wheat. Larvae were mainly Oscinella spp. and their populations ranged from <60–3100/m2 (mean 300/m2). Subsequent damage to winter wheat assessed during December of each year from 1978‐81 was positively related to the larval population in the grass. Regressions of plant damage on larval numbers indicated that 500, 1000 and 2000 larvae/m2 resulted in respectively 10, 19 and 36% damaged wheat plants. Mean populations were greatest (558/m2) in 2‐yr‐old leys containing Lolium multijlorum. Three‐yr‐old leys had a mean of 319/m2 and leys of 4 yr and older had 168 larvae/m2.Soil type and management of leys had little consistent effect on larval populations. Populations tended, however, to be larger on silty or silty‐clay loams than sandy loams and where leys were grazed in late summer after earlier silage cuts compared with those continuously grazed.
Seasonal occurrence of the potato gangrene pathogen, Phoma exigua var. foveata, in the open air
Authors: CARNEGIE S. F. 
Published: February 2008

SUMMARYUsing a Casella High Volume Bacterial Sampler air samples were collected down wind of potato fields in central Scotland when it was raining and when it was dry between December 1978 and October 1982. Airborne propagules of Phoma exigua var. foveata were recovered from the open air during rainfall in most months of the year but the frequency of recovery was greatest in September, October and November. The numbers of colonies of P. exigua var. foveata detected during rainfall were much greater in September and October than during the rest of the year. Low numbers of colonies of P. exigua var. foveata were recovered in the absence of rainfall and their occurrence appeared to be associated with strong winds and dry soil conditions. These latter airborne propagules were detected during all the months except November to February when few samples were made. Sampling simultaneously up wind and down wind of potato fields in September and October demonstrated that the potato crop was the main source of airborne propagules caught down wind but small numbers of P. exigua var. foveata were recovered up wind in four out of the seven experiments.
Studies on the occurrence of tomato bushy stunt virus in English rivers
Authors: TOMLINSON J. A. , FAITHFULL ELIZABETH M. 
Published: February 2008

SUMMARYTomato bushy stunt virus (TBSV) of unknown source was isolated from water of the River Thames, near Oxford. The isolate designated TBSV‐T was mechanically transmissible to several tomato (Lycopersicon esculentum) cvs and to other species including Petunia hybrida, pepper (Capsicum annuum). eggplant (Solanum melongena), Nicotiana clevelandii, Chenopodium amaranticolor and C. quinoa in which it caused systemic symptoms. It caused no infection of globe artichoke (Cynara scolymus) or Pelargonium domesticum.The virus was not adsorbed to soil and could be isolated from leachate of soil in which systemically‐infected tomato or C. quinoa plants were grown. Tomato plants became infected when grown in soil watered with virus suspensions.TBSV‐T was infective after 10 min at 80°C but not at 90°C and when diluted to 10‐5 but not to 10‐6. Purified virus preparations contained C. 30 nm isometric particles. In gel‐diffusion serological tests, TBSV‐T reacted with homologous anti‐serum and with antiserum to petunia asteroid mosaic virus but not to pelargonium leaf curl virus.Seed‐borne infection (50–65%) of TBSV was demonstrated in plants grown from seed of symptomlessly‐infected tomato fruit. TBSV was isolated from symptomlessly‐infected tomato fruit imported from Morocco during October‐April 1981. One of the isolates (TBSV‐M) was indistinguishable from TBSV‐T in host range, symptomatology and serological reactions. TBSV was also found in tomato plants growing extraneously in primary settlement beds at sewage works; such plants having been derived from undigested seeds in sewage. Because of its ‘alimentary‐resistance’ in man, it is possible that one ecological route whereby TBSV enters rivers is by man's consumption of TBSV‐infected tomatoes and eventual sewage dispersal into rivers.