bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of temperature on leaf development and growth in potatoes in controlled environments
Authors: KIRK W. W. , MARSHALL B. 
Published: February 2008

SummaryThree controlled environment experiments were conducted at different temperatures to determine the relation between temperature and leaf development and growth in the potato (cv. Maris Piper). Developmental stages are defined for the appearance and duration of leaf extension in the potato and comparisons made with other temperate zone crops.The rate of leaf appearance was linear over the temperature range (9–25°C) and above 25°C there was no further increase in the rate. The temperature coefficient for the rate of appearance of leaves was 0.032 leaves (degree days)‐1 using a base temperature of 0°C. The duration of extension of an individual leaf decreased with increase in temperature up to 25°C such that the thermal duration was constant at 170 degree days using a base temperature of 0°C for leaf positions 4–10 on the main stem. At higher leaf positions the thermal duration was similar or greater. The advantages and limitations of controlled environment work as a parallel to field experimentation are discussed.
The prediction of leaf canopy expansion in the leek from a simple model dependent on primordial development
Authors: HAY R. K. M. , KEMP D. R. 
Published: February 2008

SummaryIn an analysis of leaf development of leek plants grown in the field in 1988, successive leaves initiated, appeared (tip and ligule) and senesced at equal intervals of accumulated temperature/thermal time. These intervals corresponded to a plastochron of 92°C days and phyllochrons of 135 (tip) and 233 (ligule) °C days. The rate of appearance of ligules was exactly equal to the rate of leaf senescence, with the result that the number of fully‐expanded leaves per plant remained constant at 1.4. These data, which were compatible with results from previous seasons, were used to develop a model of the interrelationships between primordium initiation at the shoot apex and subsequent events in the development of individual leaves. Primordium initiation is considered to be the primary controlling event in the life of a leaf, and the processes of tip appearance, ligule appearance and death can be predicted from knowledge of the number of primordia which have been initiated, without reference to the environment. A model of canopy expansion, based on the central role of the shoot apex, was developed using the temperature relations of primordium initiation and additional data on leaf expansion and leaf dimensions. Leaf area indices computed in this way provided a satisfactory simulation of the thermal‐time course of leaf area index observed in a previous season, 1985.
The effect of micronutrient supply on the growth and seed production of guayule (Parthenium argentatum Gray)
Authors: BECKETT R. P. , van STADEN J. , ALLEN SHIRLEY 
Published: February 2008

SummaryThe effect of micronutrient supply on the growth and seed production of guayule (Parthenium argentatum Gray) was investigated. A deficiency of boron, but no other trace element, significantly reduced the growth, seed production and the percentage of seeds that germinated. The optimum concentration of B for seed production was between 20 and 100 μM. Results indicate that guayule may benefit from B fertilisation.
The effect of starvation on size and survival of the terrestrial planarian Artioposthia triangulata (Dendy) (Tricladida: Terricola)
Authors: BLACKSHAW R. P. 
Published: February 2008

SummaryTen Artioposthia triangulata were kept without food at 5°C, 10°C, 15°C, 20°C and 23°C. Survival and weights were recorded weekly. All planarians died within one week at 23°C and within three weeks at 20°C. One individual survived for 60 wk at 5°C. A negative exponential equation was fitted to average survival times for planarians kept at 5°C, 10°C, 15°C and 20°C. Negative exponential models could also describe the pattern of degrowth by planarians deprived of food. The results are discussed in relation to possible survival of the planarian outdoors in Northern Ireland and the implications for earthworm populations.
Differentiation between larvae of Tipula paludosa and Tipula oleracea (Diptera: Tipulidae) using isoelectric focusing, and their occurrence in grassland in northern Britain
Authors: HUMPHREYS I. C. , BLACKSHAW R. P. , STEWART R. M. , COLL C. 
Published: February 2008

SummaryThin layer agarose isoelectric focusing (IEF) was used to separate proteins from the larvae of Tipula oleracea Linnaeus and Tipula paludosa Meigen (Diptera, Nematocera). Silver staining revealed protein banding patterns which consistently distinguished these two species at any stage in their life cycles. Within the pH range 5–6 Tipula paludosa contained one major protein band and T. oleracea two bands, with the pI value of the T. paludosa protein being slightly higher than those of T. oleracea. The IEF method is particularly useful for the larval stages of these species because they are often visually inseparable. Leather jackets obtained during a survey of Northern Ireland and north‐eastern and western Scotland were tested to determine the distribution and frequency of these species occurring in grassland. In each area surveyed T. paludosa predominated with only one field in Northern Ireland and north‐eastern Scotland found to contain T. oleracea. In western Scotland T. oleracea occurred in five fields each year of the survey, and was locally abundant on the Isle of Bute in the 1990/91 survey making up 15% of the total larvae tested.
Effects of brief exposures to low temperature on the development, longevity and fecundity of the grain aphid Sitobion auenae (Hemiptera: Aphididae)
Authors: PARISH W. E. G. , BALE J. S. 
Published: February 2008

SummaryFirst instar nymphs and adults of the grain aphid Sirobion auenae that had been reared at 10°C and 20°C over a number of generations, were cooled to ‐5°C and ‐10°C for 1 h and 6 h and returned to 20°C to assess the effects of brief exposures to low temperatures (cold‐pulses) on their survival. rate of development, longevity and fecundity. A strong acclimation response was observed in first instar nymphs, with significantly less mortality in groups reared to 10°C compared to 20°C. Mean development time from first instar to adult was not significantly affected by low temperature exposure at the first nymphal stage. Longevity in all groups cooled as first instars was reduced by the sub‐zero cold‐pulses, and was also dependent on temperature and exposure time. Acclimated aphids survived longer than non‐acclimated individuals. Reproductive rate, in terms of the number of nymphs born per aphid per day, was unaffected by cold stress applied at the first instar stage. Total fecundity was however reduced, being a function of the number and longevity of the survivors.Adult aphids were less cold hardy than nymphs; mortality was higher at ‐10°C than ‐5°C increasing with duration of exposure from 1 h to 6 h. Mean fecundity was reduced significantly in aphids cooled at the adult stage, the number of aphids born per day decreasing as the exposure period of the cold‐pulse increased, suggesting that low temperature had affected embryogenesis. All the nymphs born to adults surviving exposure to ‐5°C for 6 h died within 48 h of birth, indicating that low temperature has a pre‐natal effect on mortality.
An eclipse of pea seed‐borne mosaic virus in vegetative tissue of pea following repeated transmission through the seed
Authors: LIGAT J. S. , RANDLES J. W. 
Published: February 2008

SummaryFour isolates of pea seed‐borne mosaic virus (PSbMV) representing pathotypes P1 (isolates US and Q) and P4 (isolates S4 and S6), and groups III (US and Q) and V (S4 and S6) have been used in a study of the survival and partitioning of PSbMV under conditions of continuous seed transmission in the commercial pea cultivar Dundale.Assays suitable for detecting virus in small tissue samples were developed, and included dot‐immunobinding assay with antisera to both PSbMV and cytoplasmic inclusion body (CIB) protein, and dot hybridisation assay (DHA) with cDNA transcribed from virus RNA. Under the conditions of our experiments, seed transmission occurred at rates exceeding 90% for all virus isolates.Virus was detectable by serology and symptoms in inoculated plants, and in all vegetative tissue of second generation plants raised from seed of the inoculated plants. However, in the third, fourth and fifth sequential generations raised from seed, all plants were symptomless. Neither virus nor CIB were detectable in leaf, stem or roots by serology, but both were readily detectable in some floral parts, and in immature and mature seed. Mature seed contained virus and CIB antigen in the testa, cotyledon and embryo. Inoculum prepared from whole seeds was infectious. The testa was shown not to be involved in transmission between generations, thus implicating the embryo alone in vertical transmission. Virus antigen could not be detected in the emerging cotyledons of germinating seed and all true leaves by serology, but the leaves contained PSbMV RNA detectable by DHA.These results show that PSbMV infection can be transferred through the vegetative phase at a subliminal level, and reaches relatively high concentrations in floral parts and seeds. Thus PSbMV may be maintained at a high level of infection in seed in the absence of any apparent symptoms in the plant, and without a requirement for horizontal transmission between plants by vectors. Such a mechanism may explain the high levels of infection commonly reported in pea breeding lines.
The enhanced infectivity of Metarhizium flavoviride in oil formulations to desert locusts at low humidities
Authors: BATEMAN R. P. , CAREY M. , MOORE D. , PRIOR C. 
Published: February 2008

SummaryFormulation in non‐evaporative diluents such as oils is required to exploit the advantages of controlled droplet application methods for biopesticides based on conidial suspensions of entomopathogenic fungi. In laboratory assays on desert locusts (Schistocerca gregaria), formulations of Metarhizium flauoviride conidia in cotton seed oil showed superior performance to water‐based suspensions and this was especially pronounced at low humidities (35% r.h.). The LD50s for oil and water suspensions at 5 days were 8900 and > 106 conidia/insect respectively. The dose‐mortality regression line for oil was more than four times steeper and median lethal times were typically 76% of those for aqueous suspensions. Formulation in oil improves the efficacy of this fungus and may extend the application of species with lipophilic conidia into less humid agricultural environments.
Crop monitoring to assess the risk of slug damage to winter wheat in the United Kingdom
Authors: GLEN D. M. , SPAULL A. M. , MOWAT D. J. , GREEN D. B. , JACKSON A. W. 
Published: February 2008

SummaryThe percentage of winter wheat seeds killed by slugs was measured, together with various risk factors, at 93 sites throughout the UK from 1987 to 1990. Estimates of slug populations at each site were obtained from traps baited with methiocarb pellets. The peak number of slugs trapped during the period from July until just before cultivation accounted for 26% of the variability in seed damage, more than any other single risk factor. A combined function of the number of slugs trapped at drilling and the percentage of fine soil aggregates in the seed‐bed accounted for 21% of the variability in seed damage. Both (i) the peak number of slugs trapped before drilling, and (ii) the combined function of number of slugs trapped at drilling and the percentage of fine soil aggregates in the seed‐bed, have potential for identifying fields with a negligible risk of slug damage to wheat seeds. However, further research is needed to improve the accuracy of forecasting slug damage. In particular, other forms of trap should be tested for their potential use in providing more accurate estimates of slug numbers and biomass at drilling, and techniques of assessing seed‐bed conditions should be improved. The percentage of seedlings grazed by slugs was correlated with the numbers of slugs trapped before drilling, at drilling and after crop emergence.
Elimination of cymbidium mosaic virus and odontoglossum ringspot virus from orchids by meristem culture and thin section culture with chemotherapy
Authors: LIM S. T. , WONG S. M. , GOH C. J. 
Published: February 2008

SummaryMost commercially cultivated orchid plants are generally infected with cymbidium mosaic virus (CyMV) and odontoglossum ringspot virus (ORSV). Two methods were used in order to generate virus‐free plants: meristem culture and thin section culture with chemotherapy. Meristems (0.10 mm to 1.00 mm) were excised from infected axillary shoots of an infected monopodial orchid hybrid (Mokara Char Kuan ‘Pink’) and cultured in modified Vacin and Went medium. Only larger meristem explants survived and the regenerated plantlets remained virus‐infected. In contrast, high percentages of virus‐free plantlets were obtained from thin section cultures of infected plantlets and protocorm‐like bodies with ribavirin treatment. Interestingly, regenerants from thin section cultures without ribavirin treatment were also found to be free from CyMV and ORSV. All plantlets were tested by enzyme‐linked immunosorbent assay (ELISA) and/or polymerase chain reaction (PCR).
Temperature accumulation and physiological ageing of seed potato tubers
Authors: JENKINS P. D. , GILLISON T. C. , AL‐SAIDI A. S. 
Published: February 2008

SummaryTubers of cv. Maris Bard were allowed to accumulate different numbers of day‐degrees early, late or continuously throughout the seed storage period. Sprout growth, time of emergence, development of early canopy cover and early tuber yield were increased more by late temperature accumulation than by increasing the number of day‐degrees experienced from 250 up to a maximum of 700°C days. The relative physiological age of seed, as indicated by the subsequent rate of early crop growth, was poorly related to the number of day‐degrees accumulated. The implications for the quantification of seed physiological age are discussed.
Crop growth, water‐use efficiency and carbon isotope discrimination in groundnut (Arachis hypogaea L.) genotypes under end‐of season drought conditions*
Authors: RAO R. C. NAGESWARA , WILLIAMS J. H. , WADIA K. D. R. , HUBICK K. T. , FARQUHAR G. D. 
Published: February 2008

SummaryTen groundnut genotypes were grown under adequately irrigated conditions or subjected to drought during the pod filling phase (83–113 days after sowing) in a medium deep Alfisol at the ICRISAT Centre during the 1986–1987 post‐rainy season. Crop growth was measured in both treatments, but transpiration (7) and water‐use efficiency (W) were quantified only in the drought treatment. Leaf samples from both treatments were assayed for discrimination against 13CO2 fixed in leaves (Δ) to examine the relationships between Δ, crop growth, and W under field conditions.The shoot dry matter accumulated during the period of drought (Y) ranged from 72–150 g m‐2 and was closely related to transpiration. This indicates scope for selection of traits and practices to increase T. Water‐use efficiencies ranged from 1.38–2.50 g kg‐1 and were inversely related to Δ in eight out of the 10 genotypes. For the other two genotypes, there was evidence that T was underestimated by field measurements. Water‐use efficiency and transpiration were not correlated suggesting that these two traits might be combined through breeding. Variation between genotypes was greatest for the partitioning of total dry matter to pods (73%), followed by water‐use efficiency (31%) and transpiration (29%). Crop growth rates were negatively related to Δ under irrigated conditions but not under drought.
Relationships between turnip root fly (Delia floralis) larval development and the sugar content of swede (Brassica napus ssp. rapifera) roots
Authors: HOPKINS R. J. , GRIFFITHS D. W. , BIRCH A. N. E. , McKINLAY R. G. , HALL J. E. 
Published: February 2008

SummaryEight genotypes of swede (Brassica napus L. ssp. rapifera [Metz.] Sinsk.) at the 8–10 true leaf stage were inoculated with five, 10 or 20 eggs of the turnip root fly Delia floralis (Fall). The roots were sampled, with control roots, after 6 weeks of larval development. D. floralis root damage, as measured by reduction in root weight, was found to be linked to inoculation level. Neither D. floralis egg numbers nor swede genotype had a significant effect on the percentage of larvae developing to pupation. Mean pupal weight varied by a factor of ×1.4 and consistently decreased with increasing egg inoculation level. Changes in the root concentrations of glucose, sucrose and fructose were measured. All swede genotypes showed a similar response in their sugar concentrations after root damage. Glucose and fructose concentrations were reduced whilst sucrose concentration remained unaffected. The concentrations of glucose and fructose were highly correlated. Pupal weight, used as a measure of larval development, was significantly correlated with the concentrations of individual and total sugars in the roots. The implications of sugar responses to damage in brassicas, and the correlation between sugar concentrations in the roots and D. floralis pupal weights are discussed.
Effects of DIMBOA levels in wheat on the susceptibility of the grain aphid (Sitobion avenue) to deltamethrin
Authors: NICOL D. , WRATTEN S. D. , EATON N. , COPAJA S. V. 
Published: February 2008

SummaryThe effects of DIMBOA in cultivars of wheat on aphid antibiosis and tolerance to the insecticide deltamethrin were investigated for the aphid Sitobion auenae. Over 48 hours the mean relative growth rate differed significantly between nymphs of S. auenae reared on wheat cultivars containing different levels of DIMBOA. Nymphs on the resistant cv. Altar showed a significantly greater susceptibility to deltamethrin, with nearly a three‐fold increase in the relative toxicity of deltamethrin, compared with the susceptible cv. Dollarbird. The LC50, adjusted for weight, was reduced by 91% for nymphs reared on the high DIMBOA cultivar. The potential for the enhancement of predation under a reduced pesticide régime is discussed in relation to this research.
Effect of surfactants and fungicides on clubroot (Plasmodiophora brassicae) of brassicas
Authors: HUMPHERSON‐JONES F. M. 
Published: February 2008

SummaryTwo formulations of the surfactant sodium dioctyl sulphosuccinate (Aerosol OT, Monawet MO70), one of alkyl phenyl ethylene oxide (Agral) and three fungicides (PP192, dichlorophen and a thiabendazole/iodophor complex ‐Byatran) were tested in field trials for control of clubroot (Plasmodiophora brassicae) on cabbage in 1988 and 1989. A standard mercurous chloride treatment (pre‐sowing compost incorporation) was included in all experiments. Plants were raised in 64 cm3 blocks (1988) or 15 cm3 free‐fill cells (1989). Mercurous chloride reduced disease severity and increased yield in both years. Byatran was ineffective. The surfactants and dichlorophen, applied as pre‐planting soaks to the plant‐raising compost, restricted disease development and increased yield in 1988 but not in 1989. A similar treatment with PP192 restricted disease severity and enhanced yield in both years. Pouring the surfactants and dichlorophen into the planting hole was more effective than using them to soak the compost. In 1989 pour treatments with Agral and a combined soak/pour treatment with dichlorophen reduced disease severity and increased yields by 250% and 97% respectively; compost treatment with PP192 gave a 150% increase.
The effect of varying rates of glyphosate and an organosilicone surfactant on the control of gorse
Authors: BALNEAVES J. M. , GASKIN R. E. , ZABKIEWICZ J. A. 
Published: February 2008

SummaryThe herbicidal effect of glyphosate applied to gorse (Ulex europaeus L.) was improved by the addition of increasing amounts (0.5–20 g/litre) of Silwet L‐77, an organosilicone surfactant. Increasing the rate of herbicide also enhanced control. There was a highly significant interaction between surfactant rate and herbicide dosage; as the amount of Silwet L‐77 was increased the rate of glyphosate could be reduced without loss of herbicide efficacy. However, without any added organosilicone surfactant, glyphosate did not provide more than 73% control of gorse at any rate up to 6.5 kg a.i./ha. With the addition of Silwet L‐77, complete mortality of all plants could be achieved with 2.2 kg glyphosate/ ha.
The genetic control of seven isozymic loci in Vicia faba L. Identification of lines and estimates of outcrossing rates between plants pollinated by bumble bees
Authors: CARRÉ S. , TASEI J. N. , GUEN J. Le , MESQUIDA J. , MORIN G. 
Published: February 2008

SummaryA simplified and non‐destructive method using starch gel electrophoresis has been developed on seeds to identify inbred lines of Vicia faba and assess outcrossing rates and gene dispersal in pollination experiments. Six enzyme systems (Alcohol dehydrogenase, Aspartate aminotransferase, Glucose‐6‐phosphate isomerase, Isocitrate dehydrogenase, Phosphogluconate dehydrogenase and Shikimate dehydrogenase) were analysed from parental lines, crosses performed between lines bearing dissimilar isozyme patterns in pollination cages with Bombus and F2 progenies obtained from manual selfing of F1 hybrids. The allozymes at each of the seven studied loci segregated in the expected Mendelian fashion and behaved in a co‐dominant manner except for the Adh‐2 locus where the only variant was a null allele. No evidence of genetic linkage was observed between at least 13 of the 15 pairs of the studied loci. Percentage of cross fertilisation by Bombus between seven pairs of inbred lines ranged between 1.7% and 28.3%. Pollen transfer between a donor line and a recipient line by two species of Bombus did not lead to differences in outcrossing rates (both about 8%). The new PGD marker with two loci at three alleles each is particularly discriminating and valuable in pollination studies and breeding of V. faba.
Effect of the stem blight pathogen, Phomopsis emicis, and the weevil, Perapion antiquum, on the weed Emex australis
Authors: SHIVAS R. G. , SCOTT J. K. 
Published: February 2008

SummaryThe stem blight pathogen, Phomopsis emicis, and the weevil, Perapion antiquum, are two potential biological control agents for the annual weed, Emex australis. Neither pathogen nor weevil affected the development of rosette (5‐wk‐old) E. australis, but both significantly reduced stem length and number of new fruits in mature plants (10‐wk‐old) in growth room experiments. Stems grew two‐thirds less than controls in plants attacked by weevils, had no net increase when both weevils and fungus were present, and collapsed in the presence of the fungus alone. Attack by weevils elicited a host response that slowed the development of the disease. Phomopsis emicis and Perapion antiquum reduced the ability of E. australis to produce new fruits by 77% and 68%, respectively. Pathogen and weevil together reduced the number of new fruits by 83%. Perapion antiquum did not carry or provide infection sites for P. emicis. The lack of damage by pathogen and weevil to rosettes could compromise their effectiveness as biological control agents.