bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on plant growth‐regulating substances LIII. The conversion of certain substituted ethylamines to active growth substances in plants
Authors: Price R. , Albores M. , Wain R. L. 
Published: February 2008

SUMMARYA number of substituted phenylethylamines have been synthesised and their plant growth‐regulating activities, in standard wheat and pea tests, have been determined and compared with those of related substituted phenoxyethylamines, phenylacetic acids and phenoxyacetic acids.The effects of applying the most active amines to various plant species are described and the results are considered in relation to the possible ability of the plant to convert the amine into the physiological active acetic acid derivative.
Some factors affecting the build‐up of cereal aphid infestations in winter wheat
Authors: HENDERSON I. F. , PERRY J. N. 
Published: February 2008

SUMMARYAphid populations were measured at 14‐day intervals during May to July 1974 in 17 fields of wheat at 10 sites along an 85 km transect running east from Hertfordshire to the Essex coast. Metopolophium dirhodum was the most numerous species initially, but was later superseded by Sitobion avenae. Rhopalosiphum padi was third in order of abundance.Several characteristics of each site and crop were examined in relation to the development of aphid infestations: two were associated with inter‐site differences in aphid infestation. Infestations started earlier at the eastern than at the western sites due to the earlier arrival of alate migrants, and this resulted in higher peak populations densities of R. padi but not of M. dirhodum or S. avenae. Greater aphid densities were associated with crops having low nitrate concentrations in plant sap in the early stages of growth.
Witches' broom disease of cocoa Crinipellis perniciosa) in Ecuador
Authors: Evans H.C. 
Published: February 2008

SUMMARYTwo pathotypes of Crinipellis perniciosa were found in both eastern and western Ecuador. The cocoa strain was highly pathogenic to species of the genera Theobrotna and Herrania and caused the witches' broom disease. The liana strain was weakly or non‐pathogenic to cocoa and its allies; it is endemic in the forests of Ecuador on lianes, shrubs and trees and is possibly parasitic in these tissues. The taxonomic position of the fungus is discussed.
Witches' broom disease of cocoa (Crinipettis perniciosa) in Ecuador.
Authors: CRONSHAW D. K. , EVANS H. C. 
Published: February 2008

SUMMARYInoculation of cocoa with basidiospores of the witches' broom fungus Crinipellis perniciosa showed that stem, petiole and pulvinus tissues of unhardened flushes and also exposed wound surfaces were susceptible to infection in addition to the growing tip. Inoculation of flower cushions and young pods showed that carrot‐shaped pods were usually the result of fertilisation of systemically infected flowers. In the absence of fertilisation such flowers produced parthenocarpic pods or chirimoyas. Transmis‐sion of the fungus via infected beans was demonstrated and this may be a potent method of long‐distance dispersal.
The effect of inoculation with Selenophoma donacis at different growth stages on spring barley cultivars
Authors: BROKENSHIRE T. , COOKE B. M. 
Published: February 2008

SUMMARYTwo spring barley field trials were established to study the importance of the time of Selenophoma donacis inoculum arrival on disease development and subsequent grain yield and quality. Inocula of two spore concentrations were applied to four barley cultivars at all combinations of three growth stages, tillering, stem extension and heading. The response varied with the stage of growth at inoculation; plants were susceptible at tillering, more resistant at stem extension and became highly susceptible at heading. Under wet conditions one application of spores at tillering gave rise to severe disease levels at heading. Treatments involving double and triple inoculum applications gave the highest disease levels on the upper leaves and awns resulting in significantly lower yields and grain quality. Significant relationships were established between disease severity at growth stages 10–1 and 11–1 and the mean yield per head, 1000 grain weight and sieving index.
Relations of carrot red leaf and carrot mottle viruses with their aphid vector, Cavariella aegopodii
Authors: ELNAGAR S. , MURANT A. F. 
Published: February 2008

SUMMARYStudies with Scottish isolates of carrot red leaf (CRLV) and carrot mottle (CMotV) viruses confirmed the dependency of CMotV on CRLV for transmission by the aphid Cavariella aegopodii. CMotV was transmitted by aphids only when the two viruses were present in the same source plant, and its transmission was not assisted by anthriscus yellows virus, which acts as a helper for parsnip yellow fleck virus. Some test plants became infected with CRLV alone, and a few with CMotV alone. In winter, aphid transmission of CRLV and CMotV was greatly increased when the source plants received supplementary lighting whereas the CMotV infectivity of sap was not increased.C. aegopodii acquired CRLV and CMotV after minimum acquisition access times of 30 min and inoculated them after minimum inoculation access times of 2 min. There was a minimum latent period of 7–18 h. The viruses were retained by the aphid after moulting and are therefore circulative in the vector, but were not transmitted to progeny insects. Aphids allowed 24 h to acquire the viruses continued to transmit them for at least 12 days, but some aphids allowed 6 h or less for virus acquisition ceased to transmit after 3 or 4 days. CRLV is considered a tentative member of the luteovirus group.
Further work on the genetics of race specific resistance in lettuce (Lactuca sativa) to downy mildew (Bremia lactucae)
Authors: JOHNSON A. G. , LAXTON SUSAN A. , CRUTE I. R. , GORDON PAMELA L. , NORWOOD JUDITH M. 
Published: February 2008

SUMMARYData are presented on the segregation of resistance to four races of Bremia lactucae in the F2 progenies of crosses involving 15 resistant and various susceptible lettuce cultivars. Most of these data and those recently published by other workers fit the systematic model for the genetics of race specific resistance to B. lactucae proposed by Crute & Johnson(1976).Seven different dominant resistance genes of major effect were found. There was also evidence of a pair of dominant genes with complementary effect, one of which may sometimes be effective on its own. Two of the genes may be linked and another may have two different alleles for resistance at the same locus. The resistance conferred by these genes is specified in relation to two British, two Dutch and four French races of the fungus. Resistance genotypes are proposed for 16 cultivars.
Studies on plant growth‐regulating substances
Authors: TAYLOR H. F. , WAIN R. L. 
Published: February 2008

SUMMARY3‐(3,5‐Dichlorophenoxy)butyric acid and 2‐(3,5‐dichlorophenoxy)ethylamine were both shown to exert pronounced dwarfing effects on tomato seedlings. Examination of extracts of the treated plants revealed the conversion of these compounds to 3,5‐dichlorophenoxyacetic acid (3,5‐D) and it is concluded that the physiological activity shown in each case depends on such a conversion to 3,5‐D within the tissues.
Insecticide resistance in damson‐hop aphid, Phorodon humuli in commercial hop gardens in Kent
Authors: MUIR R. C. 
Published: February 2008

SUMMARYFrom 1966 to 1976, samples of Phorodon humuli were collected annually from five commerical hop gardens in Kent and from other hop gardens where problems in control occurred. A susceptible stock was obtained from wild hop growing in northern England in 1969. The samples were cultured in isolation on potted hops and bioassayed against insecticides in common use. The level of resistance to demeton‐S‐methyl was c. 10X in 1966 after 10 yr use, and more than doubled from 1968–1974 apparently due to the spread of a more resistant type; there was a further increase to c. 50X in 1975–1976. There was also resistance of C. 20–30X to omethoate, 2–7X to methidathion and 4–8X to methomyl. Assays and field results show an increased resistance to methidathion and less certainly to methomyl after 5 yr use. There was no clear change in response to endosulfan. The LC50's estimated from a single dose and a mean probit slope were found to agree satisfactorily with the LC50's calculated from serial doses and so should be adequate for monitoring trends in resistance.
Judgemental probabilities for the assessment of yield response to fungicide application againstSeptoriaon winter wheat
Authors: WEBSTER J. P. G. , COOK R. J. 
Published: February 2008

SUMMARYYield responses to single applications of fungicides on winter wheat varied according to several factors of which disease incidence and spray timing were the most readily identified. In order to improve spraying decisions by farmers, judgemental distributions of yield response to spray application were specified for 16 combinations of field observations, which involved crop growth stage, disease presence, weather, cultivar susceptibility, and crop site topography. An examination of 1977 results showed that 14 out of 18 recommendations would have been correct had the scheme been in use.
Purification and properties of Australian lucerne latent virus, a seed‐borne virus having affinities with nepoviruses
Authors: JONES A. T. , FORSTER R. L. S. , MOHAMED N. A. 
Published: February 2008

SUMMARYAn isolate of Australian lucerne latent virus (ALLV) from lucerne in New Zealand was mechanically transmitted to a few herbaceous hosts. It induced diagnostic symptoms in several species of the Chenopodiaceae, but was symptomless in most other hosts including lucerne and Trifolium subterraneum. It was seed transmitted in lucerne. When assayed to Chenopodium quinoa, infective C. quinoa sap lost infectivity after diluting to 10‐4, heating for 10 min at 55°C and storage for 4 days at 4°C. ALLV was purified from infected C. quinoa or pea plants by extracting sap in 0.1 m borate buffer (pH 7) containing 0.2% 2‐mercaptoethanol and clarifying with 15% bentonite suspension, high and low speed centrifugation and sucrose density gradient centrifugation. Purified virus preparations contained isometric particles about 25 nm in diameter and sedimented as three virus components with sedimentation coefficients (s20‐w0) of 56 S, 128 S and 133 S. The 56 S component appeared to consist of nucleic acid‐free protein shells. Polyacrylamide gel electrophoresis of virus preparations showed that ALLV contained a single protein species of mol. wt 55 000 and two RNA species of mol. wt 2.1 × 106 and 2.4 × 106. An antiserum to ALLV had an homologous titre of 1/256 to purified virus but failed to detect ALLV in infective sap of C. quinoa, pea or lucerne. Purified ALLV failed to react to antisera to 28 distinct isometric plant viruses including those to 10 nepoviruses.
Chemical control of beet cyst‐nematode, Heterodera schachtii, in some peaty loam soils
Authors: WHITEHEAD A. G. , TITE D. J. , FINCH P. H. , FRASER JANET E. , FRENCH EILEEN M. 
Published: February 2008

SUMMARYIn peaty loam soils, aldicarb or oxamyl mixed with the top 15 cm of the soil in spring before sugar beet seeds were sown, minimised invasion of the roots by larvae of the beet cyst‐nematode, Heterodera schachtii, so preventing injury to the seedlings, and greatly increased sugar yields in heavily infested soil. Small amounts of both compounds were often as effective as larger amounts. Nematode increase on sugar beet roots was slow. Aldicarb or oxamyl lessened nematode increase in four years out of five. Fumigating predetermined row positions with dichloropropene mixtures (D‐D, Telone) or incorporating aldicarb or methomyl shallowly in soil, later occupied by the roots of sugar beet seedlings, did not control the nematode, although sugar yields were sometimes increased.
Incorporation of granular nematicides in soil to control pea cyst‐nematode, Heterodera goettingiana
Authors: WHITEHEAD A. G. , BROMILOW R. H. , TITE D. J. , FINCH P. H. , FRASER JANET E. , FRENCH EILEEN M. 
Published: February 2008

SUMMARYExperiments at four sites in England compared control of pea cyst‐nematode, Heterodera goettingiana, on peas, Pisum sativum, obtained when 10% granules of aldicarb or oxamyl were applied to the soil in different ways. The nematode was controlled best when the granules were incorporated in the soil by rotary cultivation (L‐bladed rotavator). The granules were incorporated too shallowly by rotary harrowing (Lely Roterra); applying granules in the seed furrows during sowing, or broadcasting them at the sowing depth of 5 cm, was only effective in 1975 when heavy and prolonged rain followed sowing.
The interaction of protectants with EPTC on field bean, and tri‐allate on wheat
Authors: BLAIR A. M. 
Published: February 2008

SUMMARYProtectants (antidotes) were tested for their potential to protect field beans (Vicia faba L.) from EPTC damage, or wheat (Triticum aestivum L.) from triallate damage. For both crops there was considerable variation in the degree of protection shown from similar treatments in different experiments. For field bean, a seed treatment of 1,8‐naphthalic anhydride (NA) at 5 mg/g seed gave some protection from EPTC applied pre‐planting at 4–8 kg a.i./ha but not in all experiments. NA also caused marked chlorosis of the foliage. N, N‐diallyl‐2, 2‐dichloroacetamide (R25788) at 20 mg/g seed severely damaged field bean in the absence of herbicide but 5 mg/g gave comparable protection from EPTC to that given by NA and did not cause chlorosis. Mixing R25788 with EPTC in the spray tank gave reduced protection. In a single experiment R4115 (chemistry undisclosed) gave some protection against EPTC damage.For wheat, a seed treatment of 5–20 mg/g NA sometimes countered damage from tri‐allate applied pre‐planting at 1 kg a.i./ha but not generally from higher doses. R25788 sometimes protected from weight loss due to tri‐allate at 1 kg a.i./ha but not from damage symptoms, whereas R4115 at 20 mg/g seed alleviated these symptoms but did not prevent weight loss. R25788 at 4 kg a.i./ha mixed in the spray tank with the herbicide partially reduced weight loss and damage symptoms from a dose of 2 kg a.i./ha. Some treatments of R29148 gave complete protection from tri‐allate at 1 kg a.i./ha.The results are discussed in the context of the full data from the two series of experiments.
A field enclosure apparatus for measuring crop photosynthesis
Authors: LEACH J. E. 
Published: February 2008

SUMMARYThe field enclosure is a transparent box covering a soil area of 1.5 m2. It is a semi‐closed system in which concentrations of water vapour and carbon dioxide are maintained constant: the required rate of input of carbon dioxide being a measure of the photosynthesis rate, and the rate of condensation of water, on cooling coils, a measure of transpiration. The air within the enclosure is circulated rapidly by fans to decrease concentration gradients, and under steady radiation inputs the air temperature is controlled to ±0.5 °C. Both photosynthesis and transpiration rates are corrected for air exchange with the surroundings, as measured through the injection of the inert gas, nitrous oxide.
Translocation of 14C‐labelled assimilates in cabbage during club root development
Authors: MITCHELL D. T. , RICE K. A. 
Published: February 2008

SUMMARYThe effects of infection of root systems by Plasmodiophora brassicae on the translocation of 14C‐labelled assimilates from the first and third leaves of cabbage seedlings were investigated. During the early phases of Plasmodium development, there were small differences in the distribution patterns of 14C‐labelled assimilate between healthy and infected seedlings. At the end of growth of plasmodia and during resting spore formation, both first and third leaves exported more assimilates than corresponding leaves of healthy seedlings. When the infected roots were dissected into various regions after exposure of the fed leaves to 14CO2, more assimilate accumulated in the club root region than in any other part.
Incidence, importance and virulence of Puccinia hordei on barley in New Zealand
Authors: ARNST B. J. , MARTENS J. W. , WRIGHT G. M. , BURNETT P. A. , SANDERSON F. R. 
Published: February 2008

SUMMARYBrown rust of barley (Puccinia hordei) is widespread in New Zealand and causes crop losses in some years. The cultivars presently grown lack adequate genetic resistance but a highly resistant line has been produced. Twelve different virulence combinations were identified in the pathogen population using the Welsh differential lines; there were differences between North Island and South Island isolates; and no virulence was observed for resistance conferred by factors Pa 3 and Pa 7.
Control of Ophiobolus patch in Agrostis turf using avirulent fungi and take‐all suppressive soils in pot experiments
Authors: WONG P. T. W. , SIVIOUR T. R. 
Published: February 2008

SUMMARYThe incorporation of avirulent fungi such as Gaeumannomyces graminis var. graminis, an avirulent isolate of G. graminis var. tritici, a Phialophora sp. with lobed hyphopodia synonymous with Phialophora radiciola var. radicicola sensu Deacon and P. radicicola var. graminicola at the time of seeding Agrostis turf in pots of sterilised soil completely controlled Ophiobolus patch disease. The addition of a 5 mm layer of take‐all suppressive (TAS) soils, artifically developed by the repeated addition of live mycelium of the varieties avenae, tritici and graminis of G. graminis to soil, controlled the disease to a lesser extent. However, a 20 mm layer of a TAS soil developed from live mycelium of G. g. avenae almost completely suppressed the disease. A survey of 66 golf and bowling greens in four states of Australia showed that P. r. graminicola was the most prevalent avirulent fungus.
Variation within and between white clover varieties in their preference for strains of Rhizobium trifolii
Authors: JONES D. GARETH , HARDARSON G. 
Published: February 2008

SUMMARYVariation within as well as between varieties of white clover (Trifolium repens L.) in their selection or preference for rhizobial strains in nodulation was studied using antibiotic‐resistant mutant strains of Rhizobium trifolii.Significant differences between varieties were found. Cv. S100 was nodulated almost exclusively by 75 str but there was more variation within S184 and, in particular, Pajbjerg smalbladet. In this experiment 93% of the total variance was genotypic, of which 68% was due to the difference between varieties and 25% due to variance between genotypes within varieties. Significant correlations were found between the preference for rhizobial strains of plants grown from seeds and of stolon lines vegetatively propagated from the former plants, indicating that the preference for rhizobial strains is genetically controlled by the host. A considerable drift in preference towards selection of more compatible rhizobial strains by the clonally propagated stolons compared with the original white clover plants was observed.The results are discussed from the point of view of improving symbiotic nitrogen fixation by combining highly effective and competitive Rhizobium strains with a host variety with uniform preference for those strains.
Host range, purification and serological properties of heracleum latent virus
Authors: BEM F. , MURANT A. F. 
Published: February 2008

SUMMARYHeracleum latent virus (HLV occurs commonly in wild plants of Heracleum sphondylium (hogweed) in Scotland without causing symptoms. It was transmitted manually or by aphids (Cavariella aegopodii, C. pastinacae or C. theobaldi) to 37 of 105 species in 11 of 18 families (especially to members of the Amaranthaceae, Chenopodiaceae, Solanaceae and Umbelliferae), but was not transmitted through seed of four species tested. It has very flexuous filamentous particles c. 730 × 12 nm in phosphotungstate, with obvious cross‐banding of pitch 3–8 nm. Leaf extracts lost infectivity after 1–2 days at 22°C, 10 min at 40–50°C and after dilution 10‐4‐10‐5. Infectivity in leaf extracts was not stabilised by addition of Mg2+, Ca2+ or Ni2+, but was abolished by EDTA. HLV was purified by bentonite clarification, precipitation with polyethylene glycol (mol. wt 6000), and differential centrifugation. Its properties resemble those of the tentative closterovirus, apple chlorotic leaf spot (ACLSV), but no serological relationship was detected to this or to any of 18 other filamentous viruses, including six definitive closteroviruses. No cross‐protection was observed between HLV, ACLSV and apple stem grooving virus.
Control of potato cyst‐nematode, Globodera pallida, on tomatoes grown under glass, by applying steam or chemical nematicides to the soil
Authors: WHITEHEAD A. G. , FRASER JANET E. , FRENCH EILEEN M. 
Published: February 2008

SUMMARYIn a sandy loam under glass, potato cyst‐nematode, Globodera pallida, was controlled in soil to 20 cm deep, and tomato yields were greatly increased by sheet steaming for 4 h, by 977 kg methyl bromide ha‐1 or by 448 kg Telone (1,3‐dichloropropene mixture or Di‐Trapex CP (20% methyl isothiocyanate: 15% chloropicrin:65% dichloropropene‐dichloropropane mixture) ha‐1 followed by 441 kg dazomet or 11.2 kg oxamyl ha‐1. Sheet steaming, unlike the other treatments, had relatively little effect on the nematode in soil 20 to 40 cm deep. Until the apices of the plants were cut off production of fruit was curvilinear against time in all treated soil but linear against time in untreated soil.
Some effects of air temperature and humidity on crop and leaf photosynthesis, transpiration and resistance to gas transfer
Authors: LEACH J. E. 
Published: February 2008

SUMMARYMeasurements of carbon dioxide exchange and transpiration were made, at various air temperatures, on wheat and barley using a field enclosure system. From these were derived the stomatal and mesophyll resistances to carbon dioxide transfer. Optimum temperatures for net CO2 uptake were about 24°C for wheat and barley. Above these optima, as temperature increased so net CO2 uptake rates decreased, because of increasing stomatal and mesophyll resistances; transpiration rates decreased in wheat but were constant in barley.In laboratory growth cabinets, wheat plants were subjected to different regimes of temperature and humidity. Optimum temperature for net CO2 uptake of individual leaves was 25°C. At constant humidity, a decline in net uptake rates above 25°C was associated with large increases in mesophyll resistance. At a constant 25°C, as the vapour pressure deficit (v.p.d. was increased above 1 k Pa (10 mb) v.p.d. the net uptake declined, with an increase in mesophyll resistance and a small increase in stomatal resistance. When the v.p.d. exceeded 1 k Pa at a temperature of 30°C, conditions that are experienced by field plants, then there were large increases in both mesophyll and stomatal resistances and the net uptake rates declined. Photo‐respiration, as measured by CO2 uptake in oxygen‐free air, was independent of temperature, but both dark respiration and CO2 compensation concentration increased with temperature.