bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purification of maize streak virus and its relationship to viruses associated with streak diseases of sugar cane and Panicum maximum
Authors: BOCK K. R. , GUTHRIE E. J. , WOODS R. D. 
Published: February 2008

SUMMARYMaize streak virus (MSV) was purified by homogenising infected leaf tissue in 0·01 m pH 3·9 phosphate buffer and clarifying the extract with n‐butanol (7 ml/100 ml extract). Purified preparations contained particles 20 nm in diameter, some occurring singly, but most occurring in pairs, forming structures of 30 × 20 nm. The sedimentation coefficients of single and paired particles were 54 and 76 S respectively.When centrifuged in sucrose density gradients preparations made by extracting leaves at pH 3·9 gave a single intense light‐scattering zone containing paired particles. Preparations made at pH 5·9 or 7·9 gave one or two additional upper zones containing single particles and fragmented material. Preparations treated with 0·05 or 0·1 m ethylene diamine tetra‐acetic acid, disodium salt, (EDTA) contained no paired particles, few single particles and much fragmented material. In immunoelectrophoresis, the major component in preparations without EDTA migrated to the cathode whereas that in EDTA‐treated preparations migrated to the anode.Virus isolates from streak‐diseased sugarcane and guinea grass (Panicum maximum) were serologically related to MSV and had similar particles with identical sedimentation coefficients. No such particles were seen in purified preparations of healthy maize, sugarcane, or guinea grass. The viruses from sugarcane and guinea grass are probably host‐adapted and are referred to correctly as the sugarcane and guinea grass strains of MSV.MSV probably contains single‐stranded RNA, and the cryptogram is (R)/1:*/*:S/S:S/Au.
Susceptibility of plants to attack by wireworms (Agriotes spp.)
Authors: GRIFFITHS D. C. 
Published: February 2008

SUMMARYIn laboratory tests, larvae of Agriotes spp. were presented with a choice between seedlings of test plants, and of wheat, which is known to be susceptible. Some plants, e.g. onion, were as susceptible as wheat to wireworm attack whilst others (mustard, cabbage, French marigold, clover and flax) were less often attacked, partly because they are small and are shallow sown. All pea and bean plants exposed to wireworms were attacked but most tolerated attack and continued to grow.
Sugar, organic acid, phenolic acid and plant growth regulator content of extracts of honeydew of the aphid Myzus persicae and of its host plant, Raphanus sativus
Authors: HUSSAIN A. , FORREST J. M. S. , DIXON A. F. G. 
Published: February 2008

SUMMARYThe honeydew of Myzus persicae feeding on radish seedlings contains glucose, fructose, trehalose, melezitose and sucrose, of which glucose and fructose are present in radish seedlings. In addition, the honeydew contains eight organic acids, of which seven are present in uninfested seedlings and six are present in infested radish seedlings: of the eighteen phenolic acids in the honeydew, five are present in uninfested radish seedlings. Auxins, gibberellins, growth inhibitors and cytokinins are present in the honeydew. The presence of carbonate and bicarbonate previously recorded in honeydew of M. persicae could not be confirmed, but ammonia is present in fresh honeydew and accounts for its high pH.
The influence of expanding leaves and the reproductive stem apex on apical dominance in Lolium multiflorum
Authors: LAIDLAW A. SCOTT , BERRIE ALEX M. M. 
Published: February 2008

SUMMARYIn vegetative plants of Lolium multiflorum removal of the two youngest emerging leaves resulted in increased expansion of basal tiller buds. A similar release of inhibition of tiller buds took place if the floriferous apex was removed. The surgical procedures did not affect the response.Under conditions of N‐deficiency total tiller number was reduced but on removal of the apex the deficient plants showed an increased initial rate of tiller bud expansion.Apical dominance during the vegetative stage of growth in this grass was apparently due to the expanding leaves in the vegetative apex, but in the flowering plant the control was exerted by the inflorescence or the elongating stem.
Resistance to bacterial blight of cotton varieties homozygous for combinations of B resistance genes
Authors: INNES N. L. 
Published: February 2008

SUMMARYIn the Sudan, inoculation experiments were done on a wide range of Egyptian cotton lines homozygous for single genes and for digenic and trigenic combinations of Knight's B genes for resistance to bacterial blight. Although leaf inoculation was successful, stem inoculation was only partially so and boll inoculation, using two different techniques, failed to produce measurable disease symptoms. There was a good general relationship between leaf and stem resistance, and a close association between resistance to natural attack in the field and leaf resistance to artificial inoculation. Confirmation was obtained of the strong resistance conferred by B2 B9K, which was as effective as B2B6 or B2B3B6. No other combination was as effective when inoculated artificially. Nevertheless, in a natural field attack, only mild symptoms were found in lines homozygous for B1 B9K and for B4B6. Under the same conditions lines with B2B6 showed no symptoms but those with B2B3 were severely attacked. Reasons for continuing to use major genes in the breeding of blight‐resistant cotton in the Sudan are discussed.
The efficiency of spawning machines for mixing insecticides into mushroom compost
Authors: WYATT I. J. , GURNEY BARBARA 
Published: February 2008

SUMMARYInsecticides incorporated into mushroom compost, using a spawning machine, are seldom mixed uniformly enough to achieve satisfactory pest control. The mixing efficiencies of various application methods and machines were investigated by mapping the distributions of fluorescent granules and emulsions under ultraviolet light. The pattern in which granules were applied to a compost block greatly affected the distribution after mixing but even uniformly peppering the surface resulted in acceptable concentrations in only 49% of the compost. Mixing twice increased this to 57%. With three times as many smaller granules, 89% of the compost was acceptably treated. Watering or spraying the compost with emulsions gave poor distributions except when the spray was directed into the spinner, which acceptably treated 83%. A machine which threw compost upwards into a hood beyond the spinner before it fell into a tray, gave better mixtures than conventional machines.The granule distribution affected the control of Heteropeza pygmaea larvae. Virtually complete control was obtained by peppering diazinon granules on to compost at 50 ppm a.i. and then mixing twice through a spawning machine.
Studies on plant growth‐regulating substances.: The effects of light and hormone inhibitors on plant root growth
Authors: WILKINS H. , LARQUÉ‐SAAVEDRA A. , WAIN R. L. 
Published: February 2008

SUMMARYLight inhibition of primary root elongation in Zea mays seedlings was found to be an almost instantaneous response and the inhibitory effect was shown to persist for at least six hours following a short exposure to white light. Removal of the root cap completely removed the inhibitory effect of light. The apical region of the root appeared to be mainly responsible for perceiving light and initiating the production of factors involved in the inhibition of elongation.Extraction of the roots of light‐exposed Zea seedlings revealed the presence of the carotenoid pigments, violaxanthin, neoxanthin and lutein, together with an unidentified non‐acidic growth‐inhibitory compound. Xanthoxin, however, was not detected.
Post‐harvest physiology of tetraploid banana fruit: response to storage and ripening
Authors: NEW S. , MARRIOTT J. 
Published: February 2008

SUMMARYAspects of the post‐harvest physiology relating to storage and ripening of the fruit of tetraploid banana clones resistant to Sigatoka disease, have been compared with fruit of Valery, an important commercial triploid cultivar. Significant differences in susceptibility to low temperature injury, duration of the preclimacteric period, the texture of pulp and peel and ethylene evolution have been found between tetraploid and Valery fruit and also between tetraploid fruit of different clones.Fruit of Valery and one tetraploid clone developed serious chilling injury during storage at 12 °C whereas that of five other tetraploid clones showed only slight damage. The preclimacteric period for fruit of two tetraploid clones was 30–45% less than for Valery fruit at an equivalent stage of physical development. Pulp firmness of preclimacteric tetraploid fruit was 20–30% less than that of Valery fruit and the differences persisted through ripening. The softening response to applied ethylene was up to 15 h earlier in fruit of tetraploid clones than of Valery but respiratory patterns, colour development and starch‐to‐sugar conversion were similar. Unlike Valery fruit, ripe tetraploid fruit did not develop senescent spotting, and shelf life was terminated by rapid deterioration of peel strength to a state of severe finger drop. Temporal and quantitative differences occurred between fruit of tetraploid clones and Valery in production of ethylene and these may relate to the observed differences in control of softening in both pulp and peel.
The development ofPuccinia hordeion barley cv. Zephyr
Authors: SIMKIN M. B. , WHEELER B. E. J. 
Published: February 2008

SUMMARYGermination of uredospores ofPuccinia hordeiwas similar on cover‐slips and on the first leaves of barley seedlings (cv. Zephyr) at 100 % r.h. over the range 5–25 °C, being greatest at 20 °C. At 15, 20 and 25 °C maximum germination was attained in 6 h. No uredospores germinated on coverslips in humidities below saturation.The numbers of pustules which subsequently developed on plants incubated at 5, 10, 15 or 18 °C and 100 % r.h. for varying periods up to 24 h, were directly related to rise in temperature and length of incubation.The time from inoculation to eruption of pustules (generation time) was 6 days at 25 °C, 8 days at 20 °C, 10 days at 15 °C, 15 days at 10 °C and 60 days at 5 °C. Pustule production on inoculated plants which had been kept at 5 °C was rapidly accelerated when they were transferred to 20 °C. Data obtained at constant temperatures were used to predict generation times of the fungus in the field.The productivity of pustules, determined as weight of uredospores, was examined at 10, 15 and 20 °C. Significantly more spores were produced at 15 than at 10 °C and most were produced at 20 °C.The results are discussed in relation to those obtained by other workers and to the development of brown rust in the field.
The effect of soil‐ and tuber‐borne inoculum on the incidence of potato gangrene
Authors: LOGAN C. 
Published: February 2008

SUMMARYUnder optimum growing conditions neither tuber‐ nor soil‐borne Phoma exigua var. foveata inoculum appreciably affected stand or yield of the subsequent potato crop. Seed tubers with gangrene rots caused high levels of stem and tuber symptoms when planted in var. foveata contaminated or uncontaminated land; contaminated seed tubers with no rots also produced progeny with a high gangrene potential.Sufficient soil‐borne inoculum was carried over in land that produced a gangrene affected crop in the previous year to override the effect of tuber disinfection. Effective gangrene control was achieved by a combination of tuber disinfection shortly after harvest over successive years with a 1 in 5 yr potato crop rotation.Gangrene rots usually developed through injuries to the tuber periderm, rots in other tubers being associated with pustules of powdery scab (Spon‐gospora subterranea).
The invasion and development of the cereal cyst‐nematode, Heterodera avenae in the roots of autumn‐and spring‐sown cereals
Authors: KERRY B. R. , HAGUE N. G. M. 
Published: February 2008

SUMMARYObservations were made at 2 or 4 wk intervals from December to harvest on all stages of Heterodera avenae in winter oats growing on infested land. Second‐stage larvae were present in all soil samples except on 5 and 20 July. Invasion and development of larvae was slow during winter. The nodal and seminal roots of winter oats were both heavily invaded by the nematode; larvae which invaded seminal roots tended to become male whereas those in nodal roots tended to become female. There was a small second invasion in August. Females were first observed on the roots of winter oats on 17 May, 214 days after the crop was sown and 62 days after the first fourth‐stage larva was observed.The nodal roots of spring barley contained few H. avenae larvae whereas these roots were heavily invaded in winter wheat and oats. In spring barley the nodal roots were developing in June and July when few second‐stage larvae were in the soil whereas in winter oats and wheat the nodal roots were growing rapidly in April when larvae were most numerous, and so were heavily invaded.
Membrane‐associated particle aggregates in extracts of plant: infected with some viruses of the potato Y group
Authors: BRUNT A. A. , ATKEY P. T. 
Published: February 2008

SUMMARYMembrane‐associated aggregates of filamentous virus particles were found occasionally in sap from plants infected with each of five distinct viruses of the potato Y group. The aggregates measured up to 960 × 700 nm and contained from four to twenty‐four virus particles. Their occurrence is apparently specifically associated with potato Y and allied viruses, observations suggesting that they may be either fragments of virus‐containing cytoplasmic strands or groups of particles enveloped during cellular disruption by pieces of tonoplast with which they are associated in vivo.
Root and shoot growth of semi‐dwarf and taller winter wheats
Authors: LUPTON F. G. H. , OLIVER R. H. , ELLIS F. B. , BARNES B. T. , HOWSE K. R. , WELBANK P. J. , TAYLOR P. J. 
Published: February 2008

SUMMARYInvestigations are reported of root and shoot growth in semi‐dwarf and taller winter wheat varieties grown in contrasting soils over three years. Comparisons were made of the distribution with depth of roots, estimated by injecting rubidium‐86 into stem bases and counting the content in soil cores. The relative ability to absorb phosphate from different zones was measured from the recovery in aerial parts of 32P injected into the soil at different depths. The distribution of dry matter in roots and aerial parts, and total root length, was measured using soil cores and samples of aerial parts taken during the growth of the crop. Relative growth rates of the aerial parts followed a sigmoid curve, but those of the roots showed little change between germination and anthesis. There was little evidence of varietal differences in root growth, though there was some indication that at depth the roots of the semi‐dwarf varieties were more extensive and absorbed more phosphate than those of the taller varieties.
Tracer studies with 32P on the distribution of functional roots of Arabica coffee in Kenya
Authors: HUXLEY P. A. , PATEL R. Z. , KABAARA A. M. , MITCHELL H. W. 
Published: February 2008

SUMMARYSeven experiments were done over a period of 21 months at Ruiru, Kenya, using 4 mCi/tree of 32P tracer to study the distribution of functional roots of mature Arabica coffee trees. Tracer was placed at sixteen equally spaced sites around individual trees at one of five depths (to 180 cm) and three distances (to 135 cm = mid‐row). Thereafter, samples of three‐leaf shoot tips were collected at 14‐day intervals for up to seven occasions and the radioactivity assessed after drying and ashing.There was negligible activity at any time at 180 cm depth but at other depths, and at all three distances, the relative level of activity changed markedly with season. After prolonged drought relatively high root activity was found at mid‐depth, near to the trunk; after the soil was re‐wetted by rain most root activity occurred in the topsoil at the quarter‐row distance; after the soil profile had been wet for some time there was a more general distribution of functional roots. Some departures from this general scheme are discussed as are practical implications and the need for further investigations.
Dispersal of the cabbage root fly
Authors: FINCH S. , SKINNER G. 
Published: February 2008

SummaryThe dispersal rates of wild and culture cabbage root flies Erioischia brassicae were determined in release‐recapture experiments at Wellesbourne in 1971–3. The experiments were concerned mainly with the first 7 days of adult life. The flies, released from nine locations in the area, were recaptured in yellow water‐traps.Dispersal was affected by wind, rain and the terrain the flies were crossing. The flies least often recaptured were those released into the host crop when 6–12 days old. The results indicated the following pattern of behaviour.Flies moved little during the first 2 days of adult life but by the third day both sexes had dispersed to c. 100 m from the release point. Flies are known to mate about the fourth day and after this the males continued to disperse at c. 100 m per day for the three subsequent days. ‘Wild’ females from field‐collected pupae carried out a ‘migratory’ flight, however, and dispersed at c. 1000 m per day during the fifth and sixth days, the days preceding the start of oviposition. Similar rates of dispersal were recorded from flies released across host crop and non‐host crop areas.Some females did not stop at the first crop they encountered. The culture females from the laboratory‐reared pupae dispersed only c. one‐third of the distance of the wild females. There was considerable intermingling of local populations. The percentage recapture of young culture and wild flies released during the pre‐oviposition period of this species was 38 ± 4 and 19 ±4 for males, and 15 + 2 and 8+1 for females, respectively.The dispersal range of the cabbage root fly is probably within a 2000–3000 m radius of the site of infestation.
Factors affecting the assessment of resistance of potatoes to gangrene (Phoma exigua var. foveata)
Authors: ROGERS W. G. , KILLICK R. J. 
Published: February 2008

SUMMARYThree experiments designed to elucidate the effects and interactions of different inoculation methods, inoculation positions, strains of Phoma exigua var. foveata and clones of potato tubers inoculated were analysed using as data dimensions of the lesions and a more general surface score. The assessment of susceptibility was affected by all these factors. The ranking of varieties for resistance altered considerably depending upon whether the surface area or the depth of lesions was considered. Derivation of more complex scores combining these measurements reduced the relative genetic component and hence would be of no value to potato breeders.
Fungitoxicity of acetaldehyde vapour to some major post‐harvest pathogens of citrus and subtropical fruits
Authors: PRASAD KRISHNA 
Published: February 2008

SUMMARYIn laboratory trials, fumigation with acetaldehyde vapour at 0–75 to 20 % concentration (v/v) for 0–5 to 120 min at 21 oC killed six species of post‐harvest citrus pathogens grown on agar media. The fungicidal effect of acetaldehyde vapour at this temperature was a function of concentration and exposure. Penicillium digitatum and P. italicum were not as susceptible to inhibition of spore germination as Alternaria citri, A. tenuis, Colletotrichum gloeosporioides and Glomerella cingulata. A concentration of 10 % acetaldehyde vapour at 21 oC for 10 min was fungitoxic to all the pathogens tested.
Role of ethylene in the effects of sucrose and other sugars on detached Sinapsis cotyledons
Authors: Moore K. G. 
Published: February 2008

ABSTRACTCulture of excised cotyledons in 6 × 10‐2 M sucrose reduces petiolar chlorophyll protein and RNA, inhibits CO2 fixation and suppresses the development of root primordia. This syndrome is preceded by enhancement of ethylene production by sucrose, particularly in the light. Glucose also increases ethylene production and petiole senescence whereas 3‐O‐ethyl glucose does not.
Ethylene in the soil atmosphere, and its effects on root growth
Authors: Smith K. A. 
Published: February 2008

ABSTRACTEthylene concentrations in the soil atmosphere can greatly exceed levels known to markedly influence plant growth. The ethylene is microbial in origin and the rate of production under anaerobic conditions is correlated with organic matter content. Under field conditions the highest concentrations occur when soil temperatures and moisture levels are high, resulting in development of anaerobic zones.Crop species differ widely in the sensitivity of their roots to ethylene, this sensitivity being broadly correlated with known intolerance of waterlogged (anaerobic) environments.
Relationship between ethylene production and sensitivity to ethylene in roots of several species
Authors: Konings H. 
Published: February 2008

ABSTRACTEthylene usually inhibited root elongation in various species, but there was some stimulation of growth at low concentrations of the gas. Evidence will be presented that the different growth responses of the roots to ethylene are related to the different levels of endogenous ethylene in these roots. These levels are probably not controlled by auxin in all roots.
Ethylene and abnormal developmental patterns in tulips
Authors: Munk W. J. DE 
Published: February 2008

ABSTRACTUnder certain conditions ethylene has very serious effects on morphogenetic processes in tulip bulbs, which can lead to the disorder bud‐necrosis. Fusarium‐infected bulbs are the main source of ethylene.Bud blasting in tulips can result from exposure of bulbs or growing plants to ethylene. There are immediate effects on growing plants and exposed bulbs produce plants that are vulnerable to unfavourable growing conditions. The occurrence of blasting can be counteracted by kinetin, GA3 and GA4+7.
The potential uses of ethephon in apple growing
Authors: Childs R. D. 
Published: February 2008

ABSTRACTThe effects of ethephon on growth, fruit bud formation and abscission in apple will be discussed in relation to the possible use of this chemical in orchards. It is possible, for example, to accelerate the ripening of fruit on trees and yet avoid abscission effects by combining ethephon with other growth regulators. In this way, the programmed harvesting of mature fruits is possible.
Physiology of ethylene production by Fusarium and possible consequences in the host‐parasite relation in tulip bulbs
Authors: Kamerbeek G. A. 
Published: February 2008

ABSTRACT Fusarium oxysporum f. tulipae produces at least 2000 times more ethylene than all other Fusarium species or formae specialis tested. Ethylene production is oxygen dependent but not correlated with the growth of mycelium.Ethylene prevents the synthesis of the antifungal compound tulipaline (methylene butyro‐lactone) in host tissue. These observations support the hypothesis that ethylene may play an important or even essential role in host‐parasite relations.