bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purification and particle properties of groundnut rosette assistor virus and production of a specific antiserum*
Authors: RAJESHWARI R. , MURANT A. F. 
Published: February 2008

SUMMARYPurified preparations of the luteovirus, groundnut rosette assistor virus (GRAV), were made by treatment of groundnut leaf extracts with cellulase, followed by sucrose density gradient centrifugation. Yields of virus particles were about 0·5‐1·0 mg/kg leaf material. The preparations contained isometric particles c. 28 nm in diameter with a sedimentation coefficient (s20, w) of 115 S, a buoyant density in Cs2SO4 of 1·34 g/cm3, and A260/A280 of 1·86. The particles contained a single species of nucleic acid (presumably RNA), of mol. wt 2·09 × 106and with no detectable polyadenylate sequence, and a single protein species, of mol. wt 24 × 103. An antiserum produced in a rabbit had a titre of 1/256 in gel diffusion tests and detected GRAV in leaf extracts by ELISA. GRAV particles reacted in F(ab')2‐ELISA and immunosorbent electron microscopy (ISEM) tests with antisera to bean leaf roll, potato leafroll and tobacco necrotic dwarf luteoviruses, but did not react with antisera to carrot red leaf luteovirus.
The effect of cherry leaf roll virus infection on the performance of birch pollen and studies on virus replication in germinating pollen
Authors: MASSALSKI THE LATE P. R. , COOPER J. I. , HELLEN C. U. T. , EDWARDS M. L. 
Published: February 2008

SUMMARYThe rates of germ tube elongation in vitro of pollen from cherry leaf roll virus (CLRV)‐infected birch (Betula pendula) did not differ significantly from those of pollen from virus‐free trees. Differences in percentage germination of pollen collected from trees at different sites were significant but percentages of germination of pollen from virus‐infected and virus‐free trees did not differ greatly from one another. In vivo, pollen from infected trees germinated on healthy and CLRV‐infected stigmas and callose plugs formed in both types of tissues.However, the extent of callose plug formation was greater in the pollen tubes of virus‐free grains germinating in infected stigmas than in reciprocal crosses. CLRV coat antigen was detected by ELISA in stigmatic tissue, from healthy trees, on which virus‐carrying pollen grains had germinated.Using fluorescein isothiocyanate conjugated to CLRV‐specific γ‐globulin, viral coat antigen was detected throughout germ tubes from virus‐carrying but not virus‐free pollen germinating in vitro. Protoplasts released following Driselase digestion of pollen germ tubes from virus‐infected trees contained CLRV antigen detectable by ELISA. During germination of virus‐infected pollen there was little synthesis of viral coat protein or nucleic acid but, following inoculation with purified virus particles, protoplasts made from healthy germinating pollen produced increasing amounts of CLRV‐specific antigen implying that CLRV replicated in this system.
Monoclonal antibodies to the soya bean cyst nematode, Heterodera glycines
Authors: ATKINSON H. J. , HARRIS P. D. , HALK E. J. , NOVITSKI C. , LEIGHTON‐SANDS J. , NOLAN P. , FOX P. C. 
Published: February 2008

SUMMARYIn order to identify proteinaceous secretions involved in feeding of the soya bean cyst nematode, Heterodera glycines, over 1800 monoclonal antibodies (MAbs) were raised in four experiments using extracts of second stage juveniles and adult females as the immunogens. A rapid, indirect immunofluorescent screening procedure is described that enabled the antigens for 100 MAbs/day to be localised in juveniles. A similar immunofluorescent screening procedure for adult females was less successful due to the masking of the fluorophore by autofluorescence; additional approaches, including enzyme linked immunosorbent assays (ELISA), were necessary to aid in the screening process. The immunosuppressive drug, cyclophosphamide, had an effect on the range of antibodies obtained in two experiments. One was designed to favour antibodies specific to the hatched rather than the unhatched juvenile, whereas the second aimed to select those for the anterior rather than the posterior part of the adult female.A large number of MAbs showed well defined specificities and numbers are given in parentheses for those that recognised the following potential sites of secretion into the plant: the subventral pharyngeal glands (84), the dorsal pharyngeal gland (5), the amphidial pouches (10) and the excretory system (15). These MAbs will aid further work to define the role of nematode secretions in host invasion and the feeding process of this cyst nematode.
Biocontrol of British bracken: the potential of two moths from Southern Africa
Authors: LAWTON J. H. , RASHBROOK V. K. , COMPTON S. G. 
Published: February 2008

SUMMARYThe spread of bracken is a major problem in upland areas of Britain. We have investigated biological methods as an alterative to traditional forms of weed control. Details are given of the life histories of two potential candidates for introduction as biocontrol agents, the Southern African mothsConservula cinisignaandPanotimasp. nearangularis.Results indicate that these species are highly host specific and potentially very destructive to bracken.
Nitrate concentration and nitrate reductase activity in the leaves of three legumes and three cereals*
Authors: NAMBIAR P. T. C. , REGO T. J. , RAO B. SRINIVASA 
Published: February 2008

SUMMARYNitrate concentration and nitrate reductase activity (NRA) were studied in the leaves of soybean (Glycine max), groundnut (Arachis hypogaea and cowpea (Vigna unguiculata) and sorghum (Sorghum bicolor), pearl millet (Pennisetum americanum) and maize (Zea mays) at three nitrogen fertiliser levels in two field experiments.Higher nitrate concentrations were detected in the leaves of groundnut, cowpea and pearl millet than in sorghum and maize. Nitrate content in the leaves and leaf NRA were not related across crop species, nor was a generalised pattern of leaf NRA and leaf nitrate observed within legumes or within cereals. Nitrogen application resulted in higher nitrate availability in the leaves, with varied leaf NRA.
The germination and emergence of seeds of winter oilseed rape stored and sown in admixture with pelleted methiocarb
Authors: ELLIS R. H. , DOLMAN G. F. S. 
Published: February 2008

SUMMARYThe possibility that pellets of the molluscicide Draza (a.i. methiocarb) might reduce field emergence of seeds of winter oilseed rape (Brassica napus, cv. Jet Neuf) when sown admixed, laboratory germination when stored admixed, or field emergence when both stored and sown admixed was the subject of three separate investigations. Admixture at sowing did not influence the emergence of five seed lots (P > 0·05). Neither did admixture influence loss in germination or change in moisture content during 2 months' storage of one lot in four different regimes (P > 0·05). Field emergence following 2 months' storage in paper bags was not influenced by admixture (P > 0·05), whereas a 12% reduction in field emergence resulting from storage in admixture within polyethylene bags was detected (P < 0·05). Thus short‐term storage within paper sacks of winter oilseed rape seeds in admixture with slug pellets containing methiocarb did not damage the seeds. The emergence of five seed lots differed considerably within and between field sowings. Tentative advice on the calculation of sowing rates for different seed lots of winter oilseed rape is provided to account for this variation.
Variation in growth of overwintered stolons of contrasting white clover populations in response to temperature, photoperiod and spring environment
Authors: EAGLES C. F. , OTHMAN O. B. 
Published: February 2008

SUMMARYThe response of overwintered stolons of nine contrasting white clover populations to temperature, photoperiod and natural conditions was studied in six environments during the spring. Rate of leaf appearance, leaflet length, petiole length, stolon internode length, dry matter distribution within the plant and total dry weight were measured on 15 plants of each population/environment combination.Most characters, except leaf size and proportion of dry matter allocated to leaf, responded positively to temperature in the range 10 – 20°C. A positive effect of photoperiod extension was also found for all characters except rate of leaf appearance, internode length and distribution of dry matter to leaf.Population differences in response to environment were found which were related to both leaf size classification and origin.Stolon dry weight was positively correlated with leaf length, petiole length and stolon internode length in most environments. The relationships between the eight characters were often complex and canonical variate analysis provided a convenient way to discriminate between the populations based on all eight characters.
Growth, light interception and disease in field bean (Vicia faba): the effect of late infection by Ascochyta fabae
Authors: MADEIRA ANA C. , CLARK J. A. , ROSSALL S. 
Published: February 2008

SUMMARYGrowth and light interception were measured in field beans (Vicia faba) infected by Ascochyta fabae under field conditions. Despite late infection, disease reduced the leaf area index and the dry matter production of the crop. The main effect was due to a decrease of leaf area duration, which resulted in shorter duration of growth and lower final dry weights. The reduction in seed yield was significant, representing a decrease of 15% compared with a prophylactic fungicide treatment. The data are consistent with a small reduction in light use efficiency, but the observed differences were not significant during the period of crop growth.
The effect of tiller removal and tiller defoliation on competition between the main shoot and tillers of spring barley
Authors: GU J. , MARSHALL C. 
Published: February 2008

SUMMARYIn glasshouse and field experiments the source‐sink relations of the main shoot of plants of spring barley were modified by tiller removal and tiller defoliation. Decreasing competition by tiller removal promoted the growth of the residual main shoot and its component parts, and the earlier tillers were removed the greater was the effect. Stem dry weight was increased four‐fold in the glasshouse by early tiller removal and was doubled in the field experiment. The grain yield of the main shoot ear was increased by 26 – 30% by tiller removal compared with tillering control plants and this was due to larger grains in all spikelet positions. On the other hand increasing competition by regular tiller defoliation had relatively little effect on the growth and development of the main shoot in the glasshouse study, but in the field the main shoot grain yield was reduced by 10% compared with the control. The main effect of tiller defoliation was on the development of tillers. In the glasshouse tillers survived repeated defoliation, continued to be produced, and the majority produced grain but with fewer and smaller grains per ear than in control plants. Tiller growth was supported by the import of assimilate from the main shoot and this was accompanied by an increase in the photosynthetic rate of the main shoot leaves. In the field all defoliated tillers died within 4 wk. These responses are discussed in terms of the physiological interrelations between the main shoot and tillers.
Serological comparison of an Australian isolate of capsicum mosaic virus with capsicum tobamovirus isolates from Europe and America
Authors: PARES R. D. 
Published: February 2008

SUMMARYA New South Wales isolate (Ca) of capsicum mosaic virus was tested against antisera to it and capsicum tobamovirus isolates from the Netherlands (P8, P11), USA (SL), Argentina (FO) and Sicily (PM). The comparison demonstrated that the four viruses Ca, P8, PM and SL are closely related to each other, forming a series of decreasing relationship to Ca in the above order. FO was related to these but insufficiently to be considered part of the group, and P11 was only slightly related to the others. The literature on serology of tobamoviruses in Capsicum spp. was collated and it is suggested that isolates from Sicily (pepper mild mottle), Australia (capsicum mosaic), The Netherlands (P8, P14) and USA (SL) be considered as strains of a virus distinct from both tobacco mosaic and tomato mosaic viruses and that these isolates all be referred to in future as strains of pepper mild mottle virus.
Alfalfa mosaic virus isolates from lucerne in South Australia: biological variability and antigenic similarity
Authors: HAJIMORAD M. R. , FRANCKI R. I. B. 
Published: February 2008

SUMMARYAlfalfa mosaic virus (AMV) was isolated from lucerne (Medicago sativa) plants with a variety of disease symptoms in eight of 13 sites in South Australia indicating that the virus is widespread in the state. The host ranges and symptomatology of the virus isolates varied considerably. Twelve selected local lesion isolates were shown to be distinct when mechanically inoculated to a range of plant species and cultivars. However, agar‐gel diffusion and enzyme‐linked immunoassay tests with polyclonal antisera prepared against glutaraldehyde‐fixed virus preparations of the five most readily distinguishable AMV isolates, failed to reveal significant antigenic differences between the 12 virus isolates. This indicates that serological tests with polyclonal antisera can detect a wide range of AMV variants but would be unlikely to differentiate between strains. The wide host range and variability of AMV precluded the grouping of isolates into strains of the virus.
Use of the cell wall‐less alga Dunaliella bioculata in herbicide screening tests
Authors: FELIX H. R. , CHOLLET R. , HARR J. 
Published: February 2008

SUMMARYAn assay was developed using Dunaliella bioculata, a cell wall‐less, unicellular alga with two flagella, to determine whether it could supplement a programme of herbicide screening. Growth was monitored by measuring the optical density of the culture. Additional information was obtained by microscopic examination; lysis of cells, loss of flagella, immobilisation, and bleaching could be readily seen. Comparing 24 commercial herbicides with an untreated check, 20 compounds clearly affected D. bioculata. The assay with D. bioculata can be used as a primary indicator of mode of action; as an example, all members of the chemical class of dinitroanilines affected movement and shape of D. bioculata, probably by influencing microtubule structure.
Pre‐harvest retting of flax: effects of water stress on uptake and efficacy of glyphosate
Authors: HARVEY B. M. R. , CROTHERS S. H. 
Published: February 2008

SUMMARYThe effects of water stress on the uptake, translocation and efficacy of glyphosate in flax were investigated in relation to pre‐harvest retting.Glyphosate (applied at a rate equivalent to 1.44 kg a.e. ha‐1 at 0, 10, 20 or 30 days after the start of flowering) caused little desiccation of flax grown in pots under restricted watering. Glyphosate application to well‐watered plants caused the moisture content to decline from an initial value of 70 – 80% to approximately 40% at 3 wk after spraying.Glyphosate was applied 2 wk after the mid‐point of flowering to flax grown in soil with moisture contents of 35, 31, 26, 22, 16 or 12%. Soil moisture levels (16% and 12%) which restricted evapotranspiration also reduced the efficacy of glyphosate but did not affect uptake of 14C‐glyphosate. Translocation of 14C‐glyphosate out of treated leaves was reduced only in the most severely stressed plants (12% soil moisture). Experiments with young plants (4 wk old) confirmed that water stress slightly reduced downward translocation of glyphosate.When the herbicide was applied to young plants under conditions which minimised differences in translocation, 10.8 μg glyphosate was sufficient to desiccate unstressed plants but 108 μg had little effect on stressed plants. This indicates that, in addition to any reduction in translocation which occurs during drought, water stress may reduce the susceptibility of flax to glyphosate. Thus only relief of plant water stress by irrigation is likely to improve response of the flax crop to glyphosate.
Harvesting and bedding practices in relation to grey mould of strawberries
Authors: SUTTON J. C. , JAMES T. D. W. , DALE A. 
Published: February 2008

SUMMARYRelationships of cultural and harvesting practices in strawberries to epidemics of grey mould, caused by Botrytis cinerea, were examined in field plots in 1983 ‐ 84 and 1984 ‐ 85. The strawberries were grown in matted rows or solid beds and harvested by hand or by machine. Foliage cut by the machine was removed by hand‐raking. Potential sporulation of B. cinerea on dead strawberry leaves, the principal inoculum source, was estimated by quantifying sporulation on samples of the leaves incubated in humidity chambers.During May, the incidence and density of sporulation, and total spore production per unit area of strawberry bed, usually were lower in plots harvested by machine in the preceding year than in those harvested by hand. Machine harvesting in the preceding year also suppressed incidence of grey mould on the fruits in June. Potential sporulation on dead leaves was usually less in solid beds than in matted rows in 1984 but not in 1985. Bed type usually did not affect incidence of grey mould fruit rot. No relationship was found between dry weights of dead leaves from sampling quadrats and potential sporulation on the leaves. It was postulated that the long‐term impact of machine harvesting on grey mould epidemics was related to removal of the majority of the foliage and berries from the plots during harvesting operations.
The prevalence of pathogens in honey bee (Apis mellifera) colonies infested with the parasitic mite Varroa jacobsoni
Authors: BALL B. V. , ALLEN M. F. 
Published: February 2008

SUMMARYThe prevalence of nine honey bee viruses in samples of dead adult bees from Apis mellifera colonies in the Netherlands and Germany infested with the parasitic mite Varroa jacobsoni was compared with virus incidence in uninfested colonies in Britain. In colonies with low mite populations the viruses present and their incidence during the year were similar to the results obtained from British colonies. However, in marked contrast with findings in Britain, acute paralysis virus (APV) was the primary cause of adult bee mortality in German honey bee colonies severely infested with V. jacobsoni. Dead brood from unsealed and sealed infested cells from German colonies with high mite populations also contained much APV.The evidence suggests that V. jacobsoni activates APV replication in adult bees by its feeding behaviour and transmits virus from adult honey bees to pupae. In addition, adult bees, in which APV is multiplying, transmit the virus to unsealed brood in the larval food.
The serological relationships and some other properties of isolates of broad bean wilt virus from faba bean and pea in China
Authors: XU Z. G. , COCKBAIN A. J. , WOODS R. D. , GOVIER D. A. 
Published: February 2008

SUMMARYAn isolate (N15) of broad bean wilt virus (BB W V) from faba bean in China was compared with some other isolates and strains including the nasturtium ringspot strain (NRSV, BBWV serotype I), parsley virus 3 (PV3, serotype I) and BBWV isolate PV131 (serotype II).In host range studies, N15 infected 12 of 14 species, including soybean and spinach. It was purified from Chenopodium quinoa and pea by a method that yielded up to 8mg/100g tissue. By the same method, NRSV yielded up to 4mg/100 g. Purified preparations of N15 and NRSV contained isometric particles c. 26 nm in diameter which sedimented as three components, N15 at 62, 93 and 117 S, and NRSV at 60, 91 and 116 S.In immunodiffusion tests using antisera to N15 and NRSV, N15 was distinguishable from NRSV but indistinguishable from PV131. In ISEM tests, many more particles of N15 and NRSV were trapped by homologous than by heterologous antiserum; in decoration tests, much antibody attached to homologous particles but none to heterologous particles. In DAS ELISA using N15 antiserum, N15 and six other Chinese faba bean or pea isolates, and a Chinese spinach isolate, were readily detected and were indistinguishable from each other and from PV131; unlike NRSV and PV3, none of the Chinese isolates, nor PV131, was detected using NRSV antiserum. These results indicate that the Chinese isolates belong to BBWV serotype II group.
Inheritance of insensitivity to tobacco rattle virus in potatoes
Authors: DALE M. F. B. , SOLOMON R. M. 
Published: February 2008

SUMMARYThe sensitivity of 20 genotypes from each of 13 progenies of parental potato clones was assessed using recently developed glasshouse testing procedures. Significant heritable differences between the progenies with respect to their degree of sensitivity to TRV were observed. Significant general and specific combining abilities were also demonstrated. The results are discussed in relation to modes of inheritance of this trait. The results indicate that though a major gene for TRV insensitivity may be operating this does not explain all the observed variation and it is suggested that there is also a system inherited in a polygenic manner that can confer good levels of insensitivity to TRV.
Effects of combining priming and plant growth regulator treatments on the synchronisation of carrot seed germination
Authors: PILL W. G. , FINCH‐SAVAGE W. E. 
Published: February 2008

SUMMARYOsmotic priming of carrot seeds for 2 wk in polyethylene glycol (PEG, — 10 MPa) at 15 °C led to more rapid and synchronous germination at 20 °C compared to untreated seeds. These responses were enhanced by a 24 h pre‐priming soak in water or a change of solution after the first 24 h of priming to remove leachate. The inclusion of 200 mg litre‐1N‐substituted phthalimide in the pre‐priming soak and/or in the PEG further enhanced the results of priming. Leachate removal combined with phthalimide inclusion gave 79% and 86% germination from seeds of two carrot cultivars during the first day in 20°C water following priming. In contrast, cumulative germination of untreated seeds of the same cultivars was 18% and 61% respectively after 3 days in 20°C water. Seeds primed in PEG containing 200 mg phthalimide litre‐1with the solution replaced after the first 24 h germinated earlier and more synchronously than untreated seeds over a range of germination temperatures (5, 10, 15, or 20°C), but the effects of priming were most marked at 5°C.
A system for studying the effects of naturally‐occurring subzero temperatures on winter barley
Authors: HETHERINGTON P. R. , STEWART W. S. 
Published: February 2008

SUMMARYThermostatically‐controlled, electrical soil heating cables were used to examine the effects of subzero temperatures on winter barley growing in plots outdoors. Plants in plots without heating cables were exposed to naturally‐occurring subzero temperatures (unheated), while those in corresponding plots with the cables (heated) were protected from such temperatures. Measurements of soil, plant and air temperatures in heated and unheated plots showed that the system can, at least with the temperatures encountered during the measurement periods, prevent plant temperature from falling below the temperature set on the thermostat. A field experiment involving different cultivars and sowing dates showed that subzero temperatures experienced did not significantly affect individual plant grain yield or the number of fertile ears produced per plant. However, small, but statistically significant, effects of naturally‐occurring subzero temperatures were found in relation to the number of grains per ear, thousand grain weight and harvest index. The nature of these effects varied, and were dependent upon cultivar and/or sowing date. Subzero temperatures were also responsible for reducing the numbers of established plants in late‐sown plots through soil heaving. Possible uses of the soil heating cable system for temperature‐related studies in the Gramineae are discussed.