bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leaf growth, stomatal diffusion resistances and photosynthesis during droughting of Lolium perenne populations selected for contrasting stomatal length and frequency
Authors: WILSON D. 
Published: February 2008

SUMMARY Lolium perenne selection lines with high calculated stomatal resistances to diffusion (rs) as a result of either few or short stomata, maintained leaf extension rates and photosynthetic rates longer than selection lines with low resistances when deprived of water. There were no significant differences between high and low rs plants in light saturated CO2 uptake of turgid attached leaves.When grown in soil drying to 21% moisture, plants with low calculated rs exhibited lower minimum leaf resistances (rl) than those with high, measured with a diffusion porometer, on all except the last day. The daily maximum rl (1.5 h after the start of the light period) became greater among low than high rs plants as the difference in rate of leaf extension between the two groups of plants increased with drying soil. Rate of leaf extension was negatively correlated with daily maximum rl and started to decline when relative leaf water content (RLWC), at 5 h after the start of the light period, fell below about 88%. Transpiration rate of plants grown in different soil moisture regimes was correlated (r=+ 0.83, P < 0.01) with mean maximum adaxial leaf conductance (reciprocal of resistance). There was a highly significant correlation (r=+ 0.62, P < 0.01) between calculated adaxial rs and mean minimum measured rl among plants growing at high or intermediate soil moisture, but not at low. Therefore, some random variation in minimum rl, even with adequate moisture, seemed to be unaccounted for by variation in stomatal numbers or size. Selection for increased numbers of adaxial stomata also resulted in more on the abaxial surface, but mean adaxial/abaxial ratio in the ‘frequent’ stomata plants was still only about 9:1.
The fungal flora of soft fruits in relation to storage and spoilage
Authors: DENNIS C. , MOUNTFORD JUNE 
Published: February 2008

SUMMARYThe fungal population of freshly harvested strawberries, raspberries and blackberries was studied throughout the fruiting seasons and the relative importance of fungi responsible for spoilage of stored fruit from different harvest dates was assessed. Botrytis cinerea, Cladosporium spp., Penicillium spp., Aureobasidium pullulans and Mucor spp. were consistently present on all three fruits while Colletotrichum gloeosporioides and Didymella applanata were prevalent on raspberries only and Epicoccum purpurascens and Alternaria spp. on blackberries only. Botrytis cinerea and Mucor mucedo were the predominant spoilage organisms of all three fruits, although the relative importance of the two fungi changed as the season progressed, especially for strawberries. Rhizopus stolonifer, Cladosporium spp., Penicillium spp. and Colletotrichum gloeosporioides were only of minor importance as spoilage organisms.
The role of Thielaviopsis basicola in the specific replant disorders of cherry and plum
Authors: SEWELL G. W. F. , WILSON J. F. 
Published: February 2008

SUMMARYThe hypothesis that Thielaviopsis basicola might be the causal agent of the specific replant disorders of cherry and plum was tested in experiments with pot‐grown trees and by observations on the distribution of the pathogen. The results obtained with certain strains of T. basicola simulated and were consistent with all features known to characterize the specific replant disorders, viz. inter‐ and intra‐generic specificity of effect; host symptoms; establishment, immobility and persistence of the causal agent in soil; normal growth of affected trees after transfer to ‘non‐replant’ soil; limited influence of soil type on the incidence of the disorder. T. basicola was therefore considered to be the probable causal agent of the specific replant diseases of certain Prunus species. The etiology of these diseases is discussed. T. basicola was neither pathogenic to apple nor associated with the growth of apple. The apparently closely similar specific replant disorder of Malus is therefore considered to be causally distinct from those of cherry and plum.
Soil populations of Thielaviopsis basicola associated with cherry rootstocks in relation to effects of the pathogen on their growth
Authors: PEPIN H. S. , SEWELL G. W. F. , WILSON J. F. 
Published: February 2008

SUMMARYLarge differences were found between populations of Thielaviopsis basicola in soils from nursery layer‐beds of different cherry rootsock clones. The soils were classified primarily into those with small (< 700 propagules/g) and those with large (3600–45000 propagules/g) populations, although significant differences occurred between soil populations in the latter group. Clones associated with small soil populations (Prunus pseudocerasus, and P. avium×P. pseudocerasus hybrids) were highly resistant to T. basicola root rot; clones associated with large soil populations (selections and intraspecific crosses of P. avium, and hybrids of P. avium × P. incisa) were susceptible. The results indicated that severe pathogenesis was associated with varying levels of parasitism in different clones, but not that extensive parasitism of cherry species occurred without pathogenesis.Resistance to T. basicola in the P. pseudocerasus hybrids is an important asset to these potential cherry rootsocks.
Bacilliform particles associated with vein yellowing of Laburnum anagyroides
Authors: SCHULTZ M. G. , HARRAP K. A. 
Published: February 2008

SUMMARYBacilliform particles characteristic of plant rhabdoviruses were found in negatively‐stained leaf sap and in thin sections of Laburnum anagyroides in England showing vein yellowing. The particles were detected principally in the perinuclear space of parenchyma cells. They were not transmitted by sap inoculation to twelve herbaceous species. The affected trees also showed mosaic symptoms but there was no evidence of an association between these and the bacilliform particles.
Laboratory methods for studying non‐preference resistance to cabbage root fly in cruciferous crops
Authors: ELLIS P. R. , HARDMAN J. A. 
Published: February 2008

SUMMARYA laboratory method for testing cruciferous plants for their non‐preference resistance to cabbage root fly is described. Test plants were fully randomized on a turntable inside a large chamber containing cabbage root flies. The apparatus was housed in a controlled environment room. The root‐fly eggs, laid in the sand surrounding test plants, were extracted using a flask flotation method which was quicker and more efficient than the stirring technique which it superseded. Two batches of plants were tested alternately, one being exposed to the flies, while the other was sampled for eggs. Each batch of test plants received three 1‐day exposures to egg‐laying, their positions within the test chamber being changed for each exposure to ensure complete randomization.This test method gave highly consistent results and indicated that there were differences in the flies' preference both between cultivars of radish and cauliflower and for individual plants within cultivars. Plants representing the extremes of preferences discovered in the two crops were saved for further study.It was not possible to correlate seed weight, time of seedling emergence, foliage surface area, or hypocotyl attitude in relation to soil level, with the egg‐laying preference of the cabbage root flies.
Further properties of black raspberry latent virus, and evidence for its relationship to tobacco streak virus
Authors: JONES A. T. , MAYO M. A. 
Published: February 2008

SUMMARYPurified preparations of an isolate of black raspberry latent virus (BRLV) contained quasispherical particles with a mean diameter of 28·5 nm; these particles were resolved into three sedimenting components (s20, w= 82S, 95S and 104S), but when centrifuged to equilibrium in caesium chloride solution they formed a single infective band (σ= 1·35 g/cm3). During electrophoresis in polyacrylamide gels, virus particles separated into three classes, and virus RNA was resolved into three major (mol. wt 1·35, 1·10 and 0·85 × 106) and one minor (mol. wt 0·4 × 106) component. The protein from virus particles had an estimated mol. wt of 28000. Isolates of BRLV were found to be serologically related but not identical to some strains of tobacco streak virus.No symptoms developed in black raspberry seedlings infected with BRLV by mechanical inoculation, nor in eight red raspberry cultivars infected by graft inoculation. However, graft inoculation of BRLV to Rubus henryi, R. phoenicolasius and Himalaya blackberry induced symptoms typical of necrotic shock disease.
Some effects of the growth‐retardant glyphosine [N, N‐bis (phosphonomethyl) glycine] on the sugar‐beet crop
Authors: JAGGARD K. W. 
Published: February 2008

SUMMARYFour experiments tested a range of doses of the growth‐retardant glyphosine on sugar‐beet crops between 1970 and 1972. The period of time between application and harvest was varied. One experiment (1972) in nutrient mist culture examined its effect on seedling root development.The growth‐retardant decreased root, sugar and top yield of sugar beet at all doses in excess of 0·56 kg a.i. ha‐1 at all treatment times. It increased the α‐amino nitrogen content of beet roots significantly (P < 0·05) with doses in excess of 1·12 kg a.i. ha‐1. When applied to the leaves of seedlings with their roots in nutrient mist culture, glyphosine at 500 ppm and 2000 ppm of a.i. in aqueous solution slowed or stopped root elongation.
Bolting in some carrot populations
Authors: DOWKER B. D. , JACKSON J. C. 
Published: February 2008

SUMMARYGenetic differences in bolting resistance between types, between varieties within types and within varieties were demonstrated in some Chantenay and Autumn King carrots and populations derived from crosses between them. The Chantenay type gave a higher proportion of bolters than the Autumn King type. Effects of sowing date and plant density on bolting were also demonstrated, later sowing and higher densities giving lower proportions of bolters. Genotype‐environment interactions were found and the responsiveness of the varieties to environment characterized by linear regression coefficients derived from a joint regression analysis. The most responsive variety tested was Red Cored Chantenay and the least responsive Rialto Improved. Implications of these findings for the breeding of new varieties with earlier harvest periods, and also for the seed multiplication of existing varieties are discussed.
The effect of vesicular arbuscular mycorrhizal associations on growth of cereals
Authors: KHAN A. G. 
Published: February 2008

SUMMARYThe growth of wheat seedlings which were already mycorrhizal when transplanted to a field deficient in phosphorus was improved compared with non‐mycorrhizal controls, and grain yield was increased three‐fold by the fungus, indicating that Endogone stimulated growth and increased yield. Differences between mycorrhizal and non‐mycorrhizal wheat were eliminated by the application of phosphate fertilizer, indicating that the fungus does not enhance wheat growth in soils containing enough available phosphate. It is probable that the mycorrhizal effect is primarily to improve the supply of phosphate. There were clear relationships between spore number in the soil and mycorrhizal development and between the extent of root infection and increased growth. The extent of root infection was greatest in mycorrhizal plants in soil not supplemented with phosphate and it decreased in inoculated plants in the plot supplemented with superphosphate.The non‐centrospermous and non‐zygophyllaceous weeds growing on the experimental field had typical vesicular arbuscular infection and indigenous Endogone spores in their rhizospheres. The centrospermous plants were non‐mycorrhizal and had no Endogone spores in their rhizospheres.
Effects of varying air and soil moisture on the water relations and growth of sugar beet
Authors: MILFORD G. F. J. , LAWLOR D. W. 
Published: February 2008

SUMMARYSugar beet were grown for short periods with different amounts of moisture in the soil and air. Growing plants in wet soil (23 % moisture on dry weight) compared with dry soil (15% moisture) increased growth of the shoots and roots and plant dry weights by 15% in young plants and 10% in mature plants. Growing plants in wet air containing 10.9 g m‐3 of water (equivalent to a saturation deficit of 2.5 mb) compared with dry air containing 6.4 g m‐3 of water (saturation deficit = 8.5 mb) increased the dry weights of both young and mature plants by 8%, mostly by increasing the sizes of their storage roots. Wet air and wet soil increased the net assimilation rates of both young and mature plants. Wet soil, but not wet air, increased leaf areas of young plants by accelerating leaf expansion, and both increased the leaf area of mature plants by slowing senescence of the older leaves. Wet soil increased the water potential of the leaves of both young and mature plants and, by doing so, increased their stomatal conductances and rates of photosynthesis. Wet air also increased stomatal conductances and rates of photosynthesis of leaves of plants of both ages, but without changing their water potentials. Stomatal conductances and photosynthetic rates were greater for young leaves than mature on the same plant and at the same water potential. It is suggested that at certain stages in the crops growth photosynthetic efficiency could be increased by applying additional water as a mist to increase the moisture content of the air around the crop.
The effects of predators on the eggs of codling moth Cydia pomonella, in a cider‐apple orchard in south‐west England
Authors: Glen D. M. 
Published: February 2008

SUMMARYIn a 2‐yr study, predators were shown to inflict heavy mortality on the eggs of codling moth, Cydia pomonella, placed in a cider‐apple orchard where no insecticidal sprays were applied. Predatory Heteroptera sucked out 35 and 57 % of the eggs in the 2 yr respectively, and smaller numbers of eggs (16 %) disappeared, probably consumed by earwigs, Forficula auricularia. The potential of these predators for an integrated control system is briefly discussed.
The effects of cocoa swollen‐shoot virus on the growth and yield of Amelonado and Amazon cocoa (Theobroma cacao) in Ghana
Authors: BRUNT A. A. 
Published: February 2008

SUMMARYThe virulent strain A of cocoa swollen‐shoot virus (CSSV) severely decreased the growth and yield of Amelonado cocoa (Theobroma cacao) trees kept free of capsids (Distantiella theobroma and Sahlbergella singularis) and the dieback fungus (Calonectria rigidiuscula) in Ghana. Fifteen per cent of graft‐inoculated Amelonado trees showed symptoms within 4 months, and 48, 80 and 100% within 6, 12 and 20 months, respectively. Infected trees, whether shaded or unshaded, began to decline 6 months after infection, and deteriorated rapidly during the next 27 months by which time 16 % had died and most others were moribund; fertilizer applications had no significant effect on the rate at which infected trees deteriorated. Yields of pods and dry cocoa were greatly reduced 2 yr after infection and were very low after 3 yr; yields were significantly reduced by virus infection but there were no significant further effects of applying fertilizer. These results confirm that CSSV strain A alone is very damaging and often eventually lethal to Amelonado trees in Ghana, and indicate that the conflicting results obtained previously in Ghana and Nigeria were probably due to differences in the virulence of the CSSV strains tested.In contrast, the virus had much less effect on cocoa trees of the Amazon type; only 3% of graft‐inoculated Amazon trees showed symptoms within 4 months, and 43, 84 and 97% after 1, 2 and 3 yr, respectively. Slight deterioration of tree canopies was first detected c. 15 months after infection and, although it continued slowly during the next 21 months, the decline was much less severe than that of Amelonado trees. Yields of both unshaded and shaded trees were apparently reduced by virus infection, but yield losses were much smaller than those of Amelonado trees. These results support the present objectives of controlling the spread of CSSV in Ghana by roguing infected trees, and selecting cultivars with greater tolerance to infection for future use.
A probable rhabdovirus infecting ryegrass (Lolium spp.)
Authors: PLUMB R. T. , JAMES MARI 
Published: February 2008

SUMMARYA particle with morphology characteristic of the rhabdovirus group was found in leaf‐dips and thin sections of symptomless Lolium spp. from several places in Britain. The particle was not transmitted mechanically nor by a number of groups of possible arthropod vectors.Despite the lack of conclusive evidence for the viral nature of the particle its morphology and intracellular localization strongly suggest that it is a member of the rhabdovirus group. This is the first report of such a particle in Lolium spp. and in Gramineae in Britain. The presumed virus is tentatively called ryegrass bacilliform virus (RBV).
Effect of temperature on virus eradication and growth of infected tissue cultures
Authors: WALKEY D. G. A. , COOPER VALERIE C. 
Published: February 2008

SUMMARYCucumber mosaic (CMV) and alfalfa mosaic (AlfMV) viruses were eradicated or their concentrations greatly diminished when infected meristem tips were grown in static or shake culture at 32 or 34 oC. Similar cultures grown at 22 oC remained infected. Tobacco mosaic virus (TMV) was not eradicated from shake cultures at 32 oC and the concentration of TMV in such cultures at 32 oC was sometimes higher than at 22 oC.The concentration of CMV and AlfMV was considerably less in cultured tissues than in infected leaf material, but that of TMV was similar. Cultures infected with CMV or TMV grew more slowly than healthy cultures. Growth of AlfMV infected and healthy cultures was similar.
Potato gangrene control by ultra low volume sprays of thiabendazole
Authors: LOGAN C. , COPELAND R. B. , LITTLE G. 
Published: February 2008

SUMMARYA method is described by which a mist of thiabendazole (TBZ) is applied to potato tubers using an ultra low volume sprayer set over rotating rollers. The fungicidal solution (2 % a.i. TBZ) is applied at 2 1/t of potatoes moving through the mist at 50 kg/min.Effective control of gangrene in storage was achieved in laboratory and farm trials.
Effects of soil applied benzimidazole fungicides on the behaviour of Cecidophyopsis ribis and on the transmission of Reversion virus
Authors: SMITH B. D. 
Published: February 2008

SUMMARYFoliar sprays of benomyl partially protected potted black currant plants from infection with gall mites, whilst soil applications gave complete protection. Soil applications of benomyl, carbendazim and thiophanate‐methyl all gave significant protection against mites under field conditions. Entry of mites into new buds was not affected by these treatments, nor was the transmission of Reversion virus. The main effect of the benzimidazole fungicides is probably on the survival of mites after entry into buds and before gall formation begins.
MBC tolerance in aggressive and non‐aggressive isolates of Ceratocystis ulmi
Authors: BRASIER C. M. , GIBBS J. N. 
Published: February 2008

SUMMARYIn selection experiments, tolerance to 0–5 ppm methyl benzimidazole‐2‐ylcarbamate (MBC) occurred at a frequency of c. 1 in 1–3 ×108 conidia in both aggressive and non‐aggressive isolates of Ceratocystis ulmi. The tolerant strains were inhibited by 5 ppm MBC, however, and attempts to select strains tolerant to 10 ppm were unsuccessful. In each of three isolates examined, tolerance remained stable after fifteen successive transfers on fungicide‐free medium. Genetic control was nuclear and probably conditioned by a single gene. It is thought unlikely that the appearance of tolerant strains in nature will jeopardize the use of MBC for the control of Dutch elm disease.
The preconditioning effect of day‐length and light intensity on adult plant resistance to powdery mildew in oats
Authors: JONES I. T. 
Published: February 2008

SUMMARYOat genotypes with partial resistance to mildew exhibited a higher level of adult plant resistance (a.p.r.) when grown in 16 h compared with 8 h day‐length. This increased resistance was expressed in the upper leaves, and to some extent in the lower, earlier‐developed leaves.The expression of increased resistance coincided with floral initiation in Maldwyn, but preceded it in CC4761. The development of a.p.r. and floral initiation were thus not inherently linked, but conditions which accelerated the plants' ontogeny also caused earlier expression of resistance.For the most efficient testing of breeding material, plants should be grown at long day‐length and high light intensity. When plants are grown at 16 h day‐length and constant temperature of 15 oC, the leaf segments should be inoculated at the 6 to 8 leaf stage because normally susceptible genotypes showed marked resistance when inoculated later.
Studies on plant growth‐regulating substances
Authors: KEMP M. S. , RIUS‐ALONSO C. , WAIN R. L. 
Published: February 2008

SUMMARYSeries of I, I‐dichloro‐2‐phenoxyethanes, α,α‐dichlorotoluenes and I, I‐dihalo‐2‐phenylethanes have been examined for plant growth‐regulating activity in a number of tests. Some compounds were shown to be active and the results, together with those obtained from metabolism studies, are discussed in terms of chemical structure/biological activity relationships and mode of action.
Induced resistance to rust diseases and its possible role in the resistance of multiline varieties
Authors: JOHNSON R. , ALLEN D. J. 
Published: February 2008

SUMMARYInoculation of wheat seedlings with a non‐virulent race of Puccinia striiformis delayed the onset of sporulation of a virulent race and also decreased the spore mass produced. Similarly, the sporulation of a virulent race of Uromyces appendiculatus on bean seedlings was reduced by application of a weakly virulent race.We suggest that these effects of induced resistance could retard the development of rust diseases in the field particularly in multiline varieties.
Seasonal fluctuations in ascospore concentrations of Didymella applanata in relation to raspberry spur blight incidence
Authors: BURCHILL R. T. , BEEVER D. J. 
Published: February 2008

SUMMARYAscospores of Didymella applanata were released in rain and dew throughout the summer, the highest concentrations occurring in May when new raspberry canes were emerging.Infections on new canes did not develop until later in the season, when ascospore concentrations were low although pycnospores were present. Lesions first appeared near the base of the green canes just below the point of attachment of the petioles; they were not associated with obvious leaf, petiole or bud infections. Once maturation of the canes occurred, further infection was prevented.
A comparison of fungicides for the control of raspberry spur blight
Authors: BURCHILL R. T. , SWAIT A. A. J. 
Published: February 2008

SUMMARYEffective control of raspberry spur blight (Didymella applanata) and increased crop yields in the following season were obtained in a plantation of cv. Mailing Jewel with a programme of four or five sprays commencing when the new canes first appeared. Treatments were applied at 14‐day intervals and continued until c. 2 wk before harvest.Thiram (0.16% a.i), benomyl (0.025% a.i.), dichlofluanid (0.10% a.i.) and captan (0.10% a.i.) gave good control of the disease but as benomyl and dichlofluanid were also effective in controlling powdery mildew (Sphaero‐theca macularis) and Botrytis cinerea on the berries these fungicides appear to be the most suitable.