bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some treatments affecting growth substances in developing wheat ears
Authors: WHEELER A. W. 
Published: February 2008

SUMMARYCytokinin, auxin and gibberellin‐like substances were bio‐assayed in extracts from developing ears of wheat plants grown in various conditions. Changes in cytokinin activity along the ears may be related to the earlier flowering in the middle of the ear. Ears on the main stems of plants from which all the tillers had been removed contained less cytokinin than the main‐stem ears of normal tillered plants. When grain development was stopped by preventing fertilization of the ovules the ear contained more cytokinin than normal ears. With de‐tillered plants, removing flag leaves before anthesis increased cytokinin, gibberellin and auxin in the ears; later removal of flag leaves did not affect cytokinin but decreased gibberellin in the ears. Conversely, removing ears before anthesis did not affect cytokinin or auxin in the flag leaves, but their gibberellin was less than that of flag leaves on intact plants. Treatment of wheat ears with zeatin did not affect grain weight or number per ear which supports the conclusion that the growth substances in the ear may be adequate for normal grain growth.
Ultrastructural changes in tea leaves during ‘orthodox’ black tea manufacture
Authors: SELVENDRAN R. R. , KING N. R. 
Published: February 2008

SUMMARYChanges in fine structure of upper epidermal and palisade cells of fresh, withered, rolled, ‘fermented’ and ‘fired’ tea leaves have been studied. In the fresh immature leaves, the polyphenols are located mainly in the vacuoles of the first two to three layers of upper palisade cells. Loss of water during withering causes slight disorganization in the fine structure of the organelles. Rolling causes extensive disorganization of the organelles, membranes and cell walls. The chloroplast membranes, which are rich in lipoproteins, rupture and parts of it vesiculate. These controlled and defined changes in fine structure leading to cell death, characterized by cleavage of cell walls in certain areas, rupture of the membranes, organelles and their inclusions, followed by‘cramped plasmolysis’ of cellular contents, throw more light on the biochemical changes that take place during tea manufacture.
Association of cocksfoot mild mosaic and cocksfoot streak viruses in Dactylis glomerata and their simultaneous transmission by aphids
Authors: CHAMBERLAIN J. A. , CATHERALL P. L. 
Published: February 2008

SUMMARY Macrosiphum (Sitobion) fragariae transmitted cocksfoot mild mosaic and cocksfoot streak viruses two to three times more frequently from plants in which they occurred together than from plants in which they occurred alone. In cells of doubly infected plants, particles of the two viruses commonly occurred in close association.
Factors affecting the control of seed‐borne Septoria nodorum by laboratory application of phenyl mercuric acetate to wheat seed
Authors: BATEMAN G. L. 
Published: February 2008

SUMMARYThe effects of distribution of fungicide between seeds and of post‐treatment storage on control of seed‐borne Septoria nodorum by phenyl mercuric acetate (PMA) were investigated. Uneven distributions of fungicide were obtained by mixing treated with untreated seed. Redistribution of PMA occurred during initial mixing of the seed and during storage; this increased the effectiveness of fungicide in the mixed seed batch when the application rate was moderately high (0–5 jug Hg/seed). Redistribution apparently occurred over the seed surfaces and from seed to seed rather than by penetration into the seeds. Penetration into the seed by PMA was relatively unimportant in controlling S. nodorum.
Glasshouse evaluation of systemic compounds, derivatives of dithiocarbamic acid and other fungicides for the control of clubroot
Authors: BUCZACKI S. T. , CADD S. E. 
Published: February 2008

SUMMARYSeventy‐one fungicides were mixed with an artificially infested soil/peat mixture in which cabbage seedlings were subsequently grown in pots in a glasshouse. The incidence and severity of clubroot and any toxic effects on the plants were recorded. Carbendazim, chloraniformethan, maneb, ferbam, zinc N‐methyl dithiocarbamate, zinc diethanolamine dithiocarbamate and ziram were selected as suitable for further evaluation as they gave disease control as good as the standard calomel treatment and were of comparably low phototoxicity.
Field evaluations of systemic fungicides and derivatives of dithiocarbamic acid for the control of clubroot
Authors: BUCZACKI S. T. , CADD S. E. , OCKENDON J. G. , WHITE J. G. 
Published: February 2008

SUMMARYDipping the roots of cabbages in aqueous suspensions of benzimidazole‐derived systemic fungicides before transplanting gave yield increases comparable with, those obtained after similar treatment with 10% calomel suspensions. In conditions of moderate clubroot infection, 0–2 % suspensions gave adequate crop improvement, but on a site where disease development was more severe, 0–4 or 0–5 % concentrations were necessary for a comparable effect. In a preliminary study, good disease control and marked crop improvement were obtained when benzimidazole‐derived systemic fungicides were incorporated to a depth of 15 cm at doses equivalent to 100 or 250 mg/kg of treated soil. Further study on lower doses and on soil incorporation techniques would be required before any large‐scale use of an incorporation method could be contemplated.
The effect of formalin on potato cyst‐nematode, Heterodera rostochiensis
Authors: WHITEHEAD A. G. 
Published: February 2008

SUMMARYApplying 5 ml of a 38% aqueous solution of formaldehyde to 1500 ml of sandy loam prevented potato cyst‐nematode, Heterodera rostochiensis, from increasing on the roots of Arran Banner potatoes planted in the soil and increased the weight of tubers produced. A comparable dosage applied to plots of sandy loam and sandy clay in winter did not prevent the nematode from multiplying on Pentland Crown potatoes but increased tuber yields. Smaller amounts of formalin had less effect on tuber yields and drenching dilute formalin solutions onto the soil was no more effective than incorporating undiluted formalin into the soil by rotavation 15 cm deep.
Relations of the semi‐persistent viruses, parsnip yellow fleck and anthriscus yellows, with their vector, Cav arietta aegopodii
Authors: ELNAGAR S. , MURANT A. F. 
Published: February 2008

SUMMARYStudies were made of the relations of parsnip yellow fleck virus (PYFV) and its helper virus, anthriscus yellows (AYV), with their aphid vector, Cavariella aegopodii. Apterous insects were more efficient vectors than alates; apterous nymphs were as efficient as apterous adults. C. aegopodii never transmitted PYFV in the absence of AYV, but aphids carrying both viruses infected some test plants with one or other virus alone. C. aegopodii that fed first on a source of AYV and then on a source of PYFV transmitted both viruses to test plants, but aphids that fed on the sources in the reverse order transmitted only AYV. Test plants receiving some aphids from a source of AYV, and others from a source of PYFV, became infected only with AYV. C. aegopodii acquired AYV or the AYV/PYFV complex from plants in a minimum acquisition access time (AAT) of 10–15 mm and inoculated the viruses to test plants in a minimum inoculation access time (IAT) of 2 min. Increasing either AAT or IAT, or both, to 1 h or longer increased the frequency of transmission of each virus. Starving the insects before the acquisition feed on AYV or AYV/PFYV sources did not affect transmission. Aphids already carrying AYV acquired PYFV from plants in a minimum AAT of only 2 min; they acquired and inoculated PYFV in a minimum total time of 12 min. The data suggest that AYV is confined to deeply lying tissues whereas PYFV is distributed throughout the leaf. C. aegopodii transmitted both PYFV and AYV in a semi‐persistent manner: the aphids retained both viruses for up to 4 days but lost them on moulting. Neither virus was passed to progeny of viruliferous adults. Earlier results suggesting that AYV is a persistent virus may have been caused by contamination of the AYV culture with carrot red leaf virus.
The role of the helper virus, anthriscus yellows, in the transmission of parsnip yellow fleck virus by the aphid Cavariella aegopodii
Authors: ELNAGAR S. , MURANT A. F. 
Published: February 2008

SUMMARYTransmission of parsnip yellow fleck virus (PYFV) by the aphid Cavariella aegopodii occurs only when the aphids are also carrying the helper virus, anthriscus yellows (AYV). None of five other viruses tested was able to act as helper. In experiments in which aphids were allowed to feed through membranes on crude or treated extracts from infected plants, aphids already carrying AYV acquired PYFV, but virus‐free aphids failed to acquire either AYV or PYFV. PYFV was not transmitted by insects injected with haemolymph from aphids carrying both viruses, or with purified preparations of PYFV. PYFV was transmitted when AYV‐carrying aphids, except those whose stylets had been removed, were contaminated externally with PYFV preparations.Ultraviolet irradiation of infected leaves did not prevent aphids from acquiring AYV, presumably because it is confined to deeply‐lying tissues. AYV‐carrying aphids could acquire PYFV from u.v.‐irradiated leaves after acquisition access times of 2 h but not after feeds of only 2 or 15 min (which are adequate on unirradiated leaves), suggesting that PYFV is present in all parts of the leaf. No ‘helper agent’ distinct from AYV itself was detected in these experiments or in experiments on minimum acquisition feeding time or maximum period of persistence in the aphid. U.v.‐inactivated PYFV competed with infective PYFV for retention sites in AYV‐carrying aphids, whereas AYV apparently did not. It is suggested that there is no helper agent for PYFV, other than AYV particles. The possibility that there is one for AYV is not excluded.
Effects of awns on the photosynthesis and yield of wheat, Triticum aestivum
Authors: OLUGBEMI L. B. , AUSTIN R. B. , BINGHAM J. 
Published: February 2008

SUMMARYTwo pairs of awned and awnless near‐isogenic lines of winter wheat were used in a field study in which canopy enclosure apparatus and carbon‐14 dosing were employed to assess the contribution of the awns to photosynthesis and grain yield. Awns contributed an average of 12‐2% to canopy gross photosynthesis but did not increase the net photosynthesis of the complete canopy. The presence of awns decreased photosynthesis in the remaining ear structures and in the flag and penultimate leaf laminae. Seven days after dosing during the phase of rapid grain filling, 80% of the carbon recovered was located in the grains. The awns intercepted 9% of the incident visible radiation when fully green, and senesced at similar rates as the ears and flag leaves.In a second experiment the effect of awns on grain yield and its components was investigated in crosses segregating for height and presence of awns. Awns did not increase grain yields in either experiment. It appears that for British conditions in the absence of severe drought there is little advantage to be gained at present by breeding awned varieties of wheat.
The incidence of benomyl tolerance in Verticillium fungicola, Mycogone perniciosa and Hypomyces rosellus in mushroom crops
Authors: FLETCHER J. T. , YARHAM D. J. 
Published: February 2008

SUMMARYOf the 229 isolates of Verticillium fungicola examined 63 % were found to show some benomyl tolerance and 53% were very tolerant having EDg, values in excess of 50 ppm. There was a tendency for the tolerant isolates to have a slower growth rate than the sensitive ones on unamended potato dextrose agar (PDA) and forty‐five isolates (19 %) showed growth stimulation at 5 ppm benomyl. No major differences were found in ten isolates of V. fungicola tested on benomyl, thiabendazole and thiophanate methyl agars or of twelve isolates compared on benomyl and carbendazim hydrochloride agars.Tolerant isolates of V. fungicola and higher levels of crop loss were linked in the east and north of the country but not in the south‐east. Tolerance was not found in sixty‐six isolates of Mycogone perniciosa or twenty‐four of Hypomyces rosellus.Benomyl was used on 89 % of the farms in the survey either applied to the casing (34%) or as a spray (55 %) or both (10%).
Use of X‐rays as a biological micro technique: an example investigating the reproductive development of cowpea (Vigna unguiculata)
Authors: ELY R. V. , MINCHIN F. R. , SUMMERFIELD R. J. , NDUNGURU B. J. , STEWART K. A. 
Published: February 2008

SUMMARYA series of preliminary trials designed to investigate the potential of long wavelength X‐rays to examine very early stages of both vegetative and reproductive growth in cowpea have been completed. This technique should allow us to ‘pin‐point’ at what stage of development a lateral bud becomes reproductive and what anatomical features precede flower development or end in flower abortion.
Factors affecting the field infection of potato tubers of different cultivars by blight (Phytophthora infestans)
Authors: LAPWOOD D. H. 
Published: February 2008

SUMMARYThe relationships between rain and blight (Phytophthora infestans) were studied in unsprayed crops of cultivars differing widely in foliage and tuber susceptibility. The occasions when tubers were infected depended on rain and not cultivar, but numbers of tubers infected after rain was affected by the blight susceptibility of the cultivar. Infected tubers were first found when less than 5 % (BMS key) of the potato foliage was infected but few fresh infections occurred when 50–75% of the foliage had been destroyed. Some tubers were infected after 8 mm rain (tubers near the surface with even less) but large increases in numbers of tubers infected usually occurred only after 25 mm or more had increased soil moisture to above ‘field capacity’ around the tuber for at least 24 h.The most susceptible cultivars Ulster Ensign and Arran Banner had all plants with some tuber blight, and some plants with all tubers affected and often many lesions per tuber. Cultivars of intermediate susceptibility, King Edward and Up‐to‐Date, had some plants without blighted tubers, many with a few and very few with all. The more resistant cultivars Majestic and Arran Viking had many plants without infected tubers and many lesions that aborted while still necrotic threads, so that the fungus did not spread. Most infections occurred through tuber eyes, lenticels or sometimes growth cracks. The distribution of blight lesions on tubers differed in the different seasons, for example, lenticels were most commonly infected on Arran Banner and Ulster Ensign and eyes on King Edward, Majestic and Arran Viking.In late or slowly developing attacks, lesions on stems became more numerous and larger than in fast, early attacks and were prolific sources of spores on King Edward and Up‐to‐Date but not on Majestic and Arran Viking. Because much rain water runs down the stems of Up‐to‐Date and King Edward, stem lesions can provide an important source of inoculum for tubers.
Laboratory studies of potato tuber resistance to infection by Phytophthora infestans
Authors: WALMSLEY‐WOODWARD DIANNE J. , LEWIS B. G. 
Published: February 2008

SUMMARYEyes and lenticels on tubers of cvs King Edward, Record, Maris Peer and Majestic gradually became more resistant to infection by Phytophthora infestans as the growing season progressed. Lenticels of Record and Majestic, and eyes of Maris Peer and Majestic were more resistant than those of King Edward. Differences in resistance between cultivars were apparent at all concentrations of inoculum.
Some properties of grapevine Bulgarian latent virus
Authors: MARTELLI G. P. , GALLITELLI D. , ABRACHEVA P. , SAVINO V. , QUACQUARELLI A. 
Published: February 2008

SUMMARYGrapevine Bulgarian latent virus (GBLV), obtained from symptomless vines grown in Bulgaria, was readily transmitted by inoculation of sap to a restricted range of hosts. The virus was re‐inoculated into virus‐free rooted cuttings and seedlings of several grapevine cultivars without inducing symptoms. Purified preparations of GBLV contained isometric particles c. 30 nm in diameter which sedimented as three components at52, c. 120 and 1275, respectively. The slow‐sedimenting component (T) contained non‐infective protein shells, whereas the two heavier classes of particles (J5X, B2) each contained one molecule of single‐stranded ribonucleic acid (RNA) with mol. wts of 2.1 and 2.2 times 106 daltons. The RNA content of B1 and B2 components were 39 and 41 % by particle weight respectively. The capsid was composed of one type of protein with a mol. wt of 54000. GBLV did not react with antisera to any of twenty‐eight viruses with isometric particles. Its present cryptogram is R/1: 2‐2/41 +2‐1/39:S/S:S/*.
Electron microscopy of cocksfoot streak virus and its differentiation from ryegrass mosaic virus in naturally infected Dactylis glomerata plants
Authors: CHAMBERLAIN J. A. , CATHERALL P. L. 
Published: February 2008

SUMMARYThe length and rigidity of some cocksfoot streak virus (CSV) particles were greater (1) in ammonium molybdate negative stain at pH 5 than at pH 8 and (2) when magnesium was added either directly to extracted plant sap or indirectly via increased plant uptake. Most CSV particles were flexuous and 750–760 run long in low concentrations of magnesium but many were rigid and 800–810 nm long in higher concentrations. In sodium phosphotungstate and ammonium molybdate at pH 5, frequency distributions of particle lengths from cocksfoot plants infected with both CSV and ryegrass mosaic virus (RMV) produced two modal peaks, one at less than 700 nm (RMV) and the other at more than 750 nm (CSV); in ammonium molybdate at pH 8, however, only one peak (at 725 nm) was resolved.In ultrathin sections of CSV‐infected cocksfoot leaves, virus‐like particles were scattered or in bundles within the cytoplasm, or aligned in aggregates near the tonoplast. Some cells contained pinwheel inclusions, often with attached or associated laminar plates and occasionally with scroll‐like or circular tubes. These CSV‐induced inclusions were easily distinguished from those induced by RMV, even when both types occurred in the same cell.
Root and shoot development in peas
Authors: ALT‐KHAN S. T. , SNOAD B. , ARTHUR A. E. 
Published: February 2008

SUMMARYThe effects of temperature were studied on six root and shoot characters in pea (Pisum sativum) seedlings. The growth response of characters to13, 16 and 19 oC in seven genotypes was linear after 9 days from sowing with growth increasing with increase in temperatures. The response to accumulated heat units of 135 oC at these three temperatures was different with a peak in growth at 16 oC.A regression analysis of genotype‐environment interactions indicated that JI181, one of the primitive forms, showed the least response to environmental change. A major portion of the genotype‐environment interaction was due to the heterogeneity of the regressions but the non‐linear or residual portion was also significant in many characters. The least variable character over all genotypes was the length of the root which was bearing laterals.
Chemical induction of mating abnormalities and spermatophore production in the Mediterranean flour moth, Ephestia kühniella
Authors: HONG TAN KENG 
Published: February 2008

SUMMARYHexamethyl‐melamine (hemel) when injected into male Ephestia kühniella induced mating aberrations expressed as permanent copulation, sterile mating and spontaneous production of spermatophore. Permanent copulation was not caused by blockage or an elongated spermatophore column but probably caused by failure of the male reproductive organs to completely transfer the spermatophore. Spontaneous spermatophore formation was induced by both cholinesterase inhibitors and nerve stimulants, the effect of the former being more pronounced. It was not caused by stress due to poisoning since DDT even at lethal doses did not induce a response. The results suggest involvement of the nervous system in spermatophore production during a normal mating.
Methods of measuring the prevalence of Phoma exigua on potatoes and in soil
Authors: HIDE G. A. , GRIFFITH R. L. , ADAMS M. J. 
Published: February 2008

SUMMARYMethods are described for assessing inoculum of Phoma exigua by directly wounding potato test tubers and by inoculating soil into Arran Banner test tubers or slices.Large samples of tubers were wounded by dropping onto perforated metal sheet or grading on farm riddles, but standardization was achieved by inflicting four uniform wounds with shaped brass teeth. Tubers were then incubated for 12 wk at 5 oC.Soil samples to be tested were inoculated into crush wounds on surface‐sterilized test tubers or tuber slices which were incubated for 8 wk at 5 oC. Assessments were speeded by immersing wounded slices in a mixture of Agrimycin and isopropylphenyl carbamate (IPC) solutions before inoculating, and then incubating for 2–3 wk at 10 oC. Although the sensitivity of test tubers is limited by their latent infection, comparisons of the tests in 3–5 years showed that the test tuber methods were frequently more sensitive than direct wounding, especially when amounts of inoculum were small.
The effect of six systemic fungicides on halo spot disease of barley caused by Selenophoma donacis
Authors: BROKENSHIRE T. , COOKE B. M. 
Published: February 2008

SUMMARYSix systemic fungicides were applied at growth stage 10 in a spring‐barley field trial, artificially inoculated with Selenophoma donacis at each of three growth stages. Barley cultivars used were Mazurka and Zephyr. The level of disease was significantly reduced by the application of chemicals, benomyl and thiophanate methyl giving the best control. Yield results did not reflect the control of disease although benomyl and thiophanate methyl applications gave slight increases in 1000 grain weight and mean yield per head. Three of the fungicides caused some phytotoxicity in cv. Zephyr and prevented grain formation.
Resistance genes in apple and biotypes of Dysaphis devecta
Authors: ALSTON F. H. , BRIGGS J. B. 
Published: February 2008

SUMMARYApple cultivars and young seedlings were repeatedly inoculated with Dysaphis devecta from six locations in South East England. Four genes governing resistance were associated with three aphid biotypes. The gene for resistance to biotypes 1 and 2 from Cox's Orange Pippin was given the symbol Sd1 while that from Northern Spy, for resistance to biotype 1 only, was designated Sd2. A single gene (Sd3) for resistance to biotype 3 was located in Malus robusta MAL 59/9 and M. zumi MAL 68/5. Worcester Pearmain, Cox, Mcintosh, Lane's Prince Albert and MAL 68/5, are heterozygous for a precursor gene Sdpr without which Sd1Sd2, and Sd3 are ineffective.
The effect of mixtures of rhizobium strains on the dry matter production of white clover grown in agar
Authors: MYTTON L. R. , FELICE J. de 
Published: February 2008

SUMMARYThe effects of mixtures of rhizobium strains on the dry matter production of S. 100 white clover were investigated by growing plants in tubes of agar with four pure strains known to give contrasts in yield effectiveness, and comparing the results with those produced by plants grown with mixtures of these strains, and with those of uninoculated plants receiving mineral nitrogen. It was found that some components of the mixtures influenced yield much more than others and these strains therefore appeared to be strong competitors. Ability to infect and capacities to fix nitrogen were shown to be mechanisms under separate genetic control; thus competitiveness and effectiveness were not necessarily linked.Variation within groups of plants inoculated with the same rhizobium strain was generally greater than within the uninoculated control receiving mineral nitrogen. The amount of variation differed from strain to strain and was largest with the intermediately effective one. The plant genotype could modify the relative competitiveness of rhizobium strains and effective association of plant and rhizobium with a high affinity for each other under competitive situations could be built up by coincidental selection of plant and bacterium.