bluuebunny/crossref_metadata_2025_split huggingface dataset:
Desiccation and storage studies on Dipterocarpm seeds
Authors: TOMPSETT P. B. 
Published: February 2008

SUMMARYThe relationship of seed moisture content (fresh weight basis) to germination, and the effect on viability of various storage conditions were examined for five species of the tropical forest tree genus Dipterocarpus. It was shown that seeds fall into two groups with regard to desiccation tolerance. Firstly, D. obtusifolius and D. turbinatus cannot be dried below about 45% moisture content without damage; a sigmoid curve was found to fit the relationship between germination and moisture content for the latter species. Secondly, D. intricatus, D. tuberculatus and D. alatus can be safely dried to 10%, 12% and 17% moisture contents respectively, but desiccation to near 7% moisture content reduced viability by at least a half. Storage studies showed that seed of D. intricatus and D. tuberculatus possessed increased longevity as moisture contents were reduced within the range 6–20%. It was concluded that seeds in the first group are ‘recalcitrant’ and that those in the second group are ‘orthodox’ in their storage physiology, according to the categories described by Roberts (1973).Wide differences between species in seed desiccation rates were observed. In 15% relative humidity D. intricatus dried to 7% moisture content within a week, whilst D. obtusifolius retained 30% moisture content even after 5 wk; other species had intermediate desiccation rates. Seed size and structure may partly account for the differences observed.Correlations were observed between seed storage physiology and other factors which were investigated. ‘Orthodox’ seeds had quicker desiccation rates, were derived from drier habitats, and had smaller embryos than those of ‘recalcitrant’ seeds.‘Orthodox’ seeds, with the possible exception of D. alatus, should be kept at 0–3°C with about 12% moisture content in the short term and, provided less than 10% germination is lost on freezing, at‐18°C with about 8% moisture content in the long term. ‘Recalcitrant’ seeds should be stored in ventilated containers at 21°C and with moisture contents above 45–50%.
The germination and the forces required to penetrate seed layers of different seedlots of three cultivars of crisp lettuce
Authors: WURR D. C. E. , FELLOWS JANE R. , DREW R. L. K. 
Published: February 2008

SUMMARYUsing 24 commercial seedlots of the lettuce cvs Ithaca, Pennlake and Saladin, the percentage germination at a range of temperatures from 20 to 35°C, and the forces required to penetrate the pericarp, the endosperm and the embryo were measured. Percentage germination declined with increasing temperature in all seedlots but there were particularly large differences between seedlots of the same cultivar at 30.0 and 32.5°C.The force required to penetrate the pericarp was on average more than twice that required to penetrate the endosperm. It is concluded that in commercial cultivars of crisp lettuce the strength of the pericarp plays a much greater role than that of the endosperm in determining germination.In all three cultivars there were significant positive correlations between seed weight and the force required to penetrate the whole seed. However only in cv. Pennlake were there significant correlations between germination at high temperature and seed penetration forces.
Gel formulations for the treatment of pruning wounds.
Authors: CLIFFORD D. R. , GENDLE P. , HOLGATE M. E. 
Published: February 2008

SUMMARYGels incorporating carbendazim and triadimefon were prepared from sodium alginate, a xanthan gum or an esterified alginic acid and evaluated as wound treatments on apple and plum trees. Fungicide movement and persistence were similar with sodium alginate and xanthan gels but movement was reduced and persistence increased with the esterified material. Callus tissue formation was not inhibited by any formulation. Adding acid to fungicides to form salts had little effect on fungicide movement or persistence and caused unacceptable phytotoxicity.Thiophanate‐methyl or thiabendazole were not superior to carbendazim, nor imazalil to triadimefon, for protection against Nectria galligena and Chondroster‐eum purpureum respectively.Sealants containing octhilinone, carbendazim plus captan, or mercuric oxide quickly established sufficient fungicide in the wood to eradicate N. galligena but possibly insufficient to protect adequately against C. purpureum.Gel formulations are valid alternatives to sealants as fresh wound pathogen treatments but fungicide persistence is insufficient for them to be recommended for treatment against mature wound pathogens.
Factors affecting competition of three strains of rhizobia nodulating groundnut, Arachis hypogaea*
Authors: NAMBIAR P. T. C. , ANJAIAH V. , RAO B. SRINIVASA 
Published: February 2008

SUMMARYThe nitrogen (N2) fixing ability of three strains of rhizobia (NC 92, NC 43.3, and TAL 176) was compared in groundnut cv. Robut 33–1. The competitiveness of these strains in pot culture in a sand‐vermiculite medium and with native rhizobia in the field was also investigated. In pot culture, NC 43.3 formed more nodules than TAL 176 and NC 92. Nodules formed by NC 43.3 and NC 92 fixed more N2 (as measured by total N content in the plants at 42 days after sowing) than nodules formed by TAL 176. TAL 176 was a poor competitor compared with NC 92, NC 43.3, or with native rhizobia in the field. NC 92 when mixed with NC 43.3 (106 cells seed‐1 of each strain) formed only 21% of the nodules, but when independently inoculated in the soil containing native rhizobia, the two‐strains formed similar percentages of nodules. Thirty percent of the nodules in two strain combinations of NC 43.3 and NC 92 showed double occupancy. Strain NC 43.3 formed nodules earlier than NC 92 and TAL 176 and this may be one of the factors responsible for its better N2‐fixation and competitiveness. Nodules formed earlier by one strain (NC 92 or TAL 176) were found to have no effect on the subsequent nodulation by the other (TAL 176 or NC 92) strain. Although NC 92 and NC 43.3 were equally competitive with native rhizobia in the field and NC 43.3 fixed more N2 than NC 92 in pot culture, earlier experiments indicated that only inoculation with NC 92 increased pod yield in field trials.
Control of contamination of potatoes with air‐borne Erwinia carotovora by foliar application of copper oxychloride
Authors: ELPHINSTONE J. G. , PÉROMBELON M. C. M. 
Published: February 2008

SUMMARYIn field experiments in 1983 and 1984, micropropagated plants of cv. Désirée planted in soil tested and found free of erwinias became contaminated with airborne erwinias, mostly E. carotovora pv. carotovora, in September when rain was more abundant, but not earlier. Control of contamination of progeny tubers harvested in September and October was achieved by spraying plants with copper oxychloride (‘Cuprokylt’; 5 g litre‐1) twice weekly from June or July but not from August nor by weekly or fortnightly treatments from June. Bactericidal activity of copper in the effective spray regimes was not expressed on the leaves or in the soil and contamination was similar in the sprayed and unsprayed treatments. In contrast, multiplication of erwinias in senescent leaves on the soil surface (leaf debris) was inhibited in the sprayed treatment but not in the unsprayed treatment and population numbers of c. 103 cells g‐1 fresh weight were detected. It is suggested that fewer erwinias would be washed from leaf debris by rain in the sprayed than in the unsprayed treatment to contaminate the progeny tubers.
The use of insecticides to control maize rough dwarf virus (MRDV) in maize*
Authors: ANTIGNUS Y. , KLEIN M. , OVADIA S. 
Published: February 2008

SUMMARYInsecticides were screened in the laboratory for fast action against the delphacid planthopper, Laodelphax striatellus, the vector of maize rough dwarf virus (MRDV) in Israel. In these tests the synthetic pyrethroids were more efficient than oxydemeton‐methyl or endosulfan giving 50% mortality after 5 h compared to 10% in the non‐pyrethroid insecticides. Selected insecticides were then tested in maize fields for their effect on disease spread and crop yield. The synthetic pyrethroids cypermethrin, fluvalinate and biphenthrin reduced MRDV incidence by 22–59% and disease was less severe in the treated plots. Total crop yield (stems, leaves, ears) was 28% higher in the biphenthrin‐and fluvalinate‐treated plots than in untreated plots.
Purification and some properties of a new strain of cowpea mild mottle virus in Israel*
Authors: ANTIGNUS Y. , COHEN S. 
Published: February 2008

SUMMARYThe virus responsible for tomato pale chlorosis disease in Israel was purified from Nicotiana glutinosa plants. Purified virus contained a single stranded RN A of mol. wt 2.5 × 106 and a single coat protein subunit of mol. wt 31 000. Enzyme‐linked immunosorbent assay and an immunoelectron microscopy decoration test demonstrated a serological relationship with cowpea mild mottle virus (CMMV). Based on the present study and previously reported data the virus was identified as a new strain of CMMV designated CMMV/I.
Honeydew production and sap ingestion by the cereal aphids Rhopalosiphum padi and Metopolophium dirhodum on seedlings of resistant and susceptible wheat species
Authors: SPILLER N. J. , LLEWELLYN M. 
Published: February 2008

SUMMARYMeasurements of the frequency and rate of honeydew excretion by Rhopalosiphum padi and Metopolophium dirhodum, feeding on seedlings of resistant and susceptible wheat (Triticum monococcum and T. aestivum) were used to estimate the quantity of sap ingested over 24 h. Ingestion was significantly reduced on the more resistant T. monococcum and for M. dirhodum this may be due in part to a reduction in the success of phloem location.
The integration of host resistance with fungicides in the control of oat powdery mildew
Authors: JONES I. T. , RODERICK H. W. , CLIFFORD B. C. 
Published: February 2008

SUMMARYTreatment of seed with the systemic fungicides triadimenol plus fuberidazole as Baytan significantly decreased powdery mildew in field experiments involving eight oat cultivars differing widely in their resistance to the disease. This was so up to growth stage G.S. 61 (Zadoks) even in a year of high mildew incidence, although the effect diminished after flowering.Significant (P≥ 0.001) interactions between fungicide treatments and cultivars occurred in each of three years at nearly all assessment times. In years of high mildew incidence (1983 and 1984), susceptible cultivars developed similar levels of mildew in seed‐treated and untreated plots by about flowering time, although cultivars with adult plant resistance (APR) had significantly less mildew when seed‐treated than when left untreated. Later, as the APR was fully expressed and the fungicide effectiveness was declining, similar mildew levels were recorded on treated and untreated plots. Untreated APR cultivars generally had less mildew than treated susceptible cultivars and in a year of late and light mildew, APR alone provided good protection. Seed treatments combined with foliar sprays of tridemorph as Calixin almost completely controlled mildew except on very susceptible cultivars late in the season in high mildew years.Over all cultivars, seed treatment gave yield advantages of 5.3% (1983) and 6.6% (1984) but in 1982, a year of low mildew, the response was small.The possible influence of integrated host resistance and fungicides in stabilising the pathogen population at economically unimportant levels and the environmental benefit of using host resistance to minimise fungicide usage is discussed.
Effects of delaying fungicide treatment and of curing and chlorpropham on the incidence of skin spot on stored potato tubers
Authors: HIDE G. A. , CAYLEY G. R. 
Published: February 2008

SUMMARYPotato tubers wounded with pin pricks and inoculated with Polyscytalum pustulans were not treated or treated with fungicide on the following day or after holding them in dry or damp conditions at 5, 10 or 15°C for periods up to 21 days. Tubers were then stored in damp conditions at 5°C and skin spot assessed after 24 wk. Disease was progressively decreased on untreated tubers by increasing the holding time and temperature in dry, but not damp conditions. Curing at 15°C for 14 days in dry conditions decreased the incidence of skin spot from 70% prick wounds infected to 4% but in damp conditions to only 53%. Fungicides controlled disease best when applied the day after inoculation, and more disease developed on tubers treated after holding in damp rather than dry conditions.Incidence of skin spot in store on naturally infected tubers increased the later they were harvested. Carbendazim controlled the disease when applied immediately after harvest or up to 2 wk later and efficacy was greater after early than late harvest.More skin spots developed on inoculated tubers stored at 5 than at 10°C but applying the sprout suppressant chlorpropham (CIPC) increased the number and size of spots, especially on tubers stored at 10°C. The disease was increased most by CIPC applied 2 days after inoculation; treatment after 5 but not after 10 wk also increased it. CIPC also slightly increased skin spot on tubers previously treated with carbendazim.These experiments with naturally infected or inoculated tubers showed that skin spot in store can be decreased by early harvesting, by curing in dry conditions and by applying fungicide to tubers soon after harvest. They also indicated that when tubers are harvested damp, the disease can be controlled by drying or, if fungicides cannot be applied immediately, the tubers should be kept cool before treatment.
Effects of seed treatment with a plant growth regulator on growth and tillering in spring barley (Hordeum distichum) cv. Triumph
Authors: WOODWARD E. J. , MARSHALL C. 
Published: February 2008

SUMMARYDoses of the growth retardant, Terpal, were applied to seeds of spring barley. Germination was delayed as the concentration and duration of exposure to Terpal increased. Tiller bud outgrowth was promoted in treated seedlings and at maturity the total tiller production and number of ear‐bearing tillers per plant was increased by the Terpal treatment. The yield of the main shoot was similar in both control and treated plants but the mean ear weight of the tillers was reduced in the latter, and thus there was no overall effect of the treatment on yield. Observations on vegetative plants showed that Terpal also reduced the growth of successive main shoot leaves and the elongation and dry weight of the seminal root system. The results are discussed in terms of an early modification in the distribution of resources during establishment that favour the outgrowth of tiller buds at the expense of the initial development of the main shoot and root system. It is proposed that seed treatment is a viable alternative to foliar spraying particularly in arid regions.
Elimination of stem pitting and corky bark diseases from grapevine by fragmented shoot apex culture
Authors: BARLASS M. 
Published: February 2008

SUMMARYFragmented shoot apex culture of grapevine has been shown to regenerate plants free from the graft‐transmissible diseases stem pitting (legno riccio) and corky bark. The efficiency of elimination of the disease agents following 2 years of indexing based on 66 plants of three varieties was 100%.
Further studies relating chlorogenic acid concentration in carrots to carrot fly damage
Authors: COLE ROSEMARY A. , PHELPS KATHLEEN , ELLIS P. R. , HARDMAN J. A. , ROLLASON S. A. 
Published: February 2008

SUMMARYThe effects of first generation carrot fly larval damage on chlorogenic acid concentration in carrots was investigated in a field experiment at Wellesbourne in 1985. In a separate experiment carrots grown in the absence of a resident population of carrot fly were also analysed for chlorogenic acid; these carrots maintained low concentrations of chlorogenic acid through the summer and autumn until low ground temperatures occurred from November to January. The relationship between chlorogenic acid concentration and damage by the first generation of carrot fly was described by a similar model to the one derived previously for late‐generation damage but without the cultivar dependence. This may have been because first generation damage takes place in mid‐summer when soil temperature is not sufficiently low for differential chlorogenic acid production by carrot cultivars. The model supports the hypothesis that carrot fly damage increases chlorogenic acid production which subsequently encourages further attack. The increase in acid production due to the low winter temperature may be the mechanism which, in turn, induced a differential cultivar response in carrots harvested during the winter.
The effects of Pythium sylvaticum, seed‐borne pathogens and seed treatments on the emergence of brassica seedlots of high vigour
Authors: WHITE J. G. , HO R. K. 
Published: February 2008

SUMMARYThe emergence from brassica seedlots designated by seed merchants as being of high vigour was measured in sterilised soil and in sterilised soil re‐inoculated with Pythium sylvaticum. The mean emergence level of 93·9% in the former compared favourably with the known mean total viability of the seedlots (97·7%). However, P. sylvaticum reduced emergence of 10 out of 16 untreated seedlots. The majority of seedlots gave > 75% emergence but in three cases emergence was reduced by 32·5–40·0%. The effects were not related directly to time taken to emerge, nor were the seedlots most affected those with high levels of infection. A compound seed treatment containing metalaxyl, fenpropimorph and gamma‐HCH restored high emergence levels.
Degradation of pectic substances in green flax fibre by Erwinia carotovora
Authors: MORVAN ODILE , JAUNEAU ALAIN , MORVAN CLAUDINE , DEMARTY MAURICE , RIPOLL CAMILLE 
Published: February 2008

SUMMARYIn this paper, we report that Erwinia carotovora can perform controlled biological pectinolysis of green flax fibre. The degradation of pectic substances is considered a key step during this process and is estimated by determining the cation exchange capacity (CEC). A CEC characteristic of a ‘good retting degree’, is reached after 20 h incubation, whatever the tested temperature and initial pectate lyase activity of the bacterial culture. Similar results are obtained after only 4 h, at a temperature of 45°C and the pectate lyase activity is greater than 2 nmol ml‐1 min‐1. The linear relationship between the CEC and the weight loss of green fibre which is established, allows us to estimate an equivalent weight of 1000 g eq‐1 for the solubilised polymers.
Identification and characterisation of a newly described potyvirus in West Africa: Asystasia mottle virus
Authors: THOUVENEL J.‐C. , FAUQUET C. , FARGETTE D. 
Published: February 2008

SUMMARYAsystasia mottle virus (AsMV) was detected serologically in samples of Asystasia gangetica with mottle symptoms, from several areas of tropical West Africa. It infected 12 species systemically and induced local lesions in a further four.The virus lost infectivity after dilution to 10‐4, after 10 min at 75 °C and after 3 days at 27°C. Purified virus had an A260/A280 ratio of c. 1·2 and a protein subunit mol. wt of c. 33 000. Particles were c. 750 nm long and cytoplasmic inclusions typical of potyviruses were seen in ultrathin sections of infected leaves. The antiserum prepared had a titre of 1/1024 in microprecipitin tests but purified virus failed to react with 31 antisera to known potyviruses.The virus was transmitted in the non‐persistent manner by Aphis spiraecola but only very infrequently. On the basis of these properties, AsMV is considered to be a new member of the potyvirus group.
Studies on the growth and development of Oxalis latifolia
Authors: MARSHALL G. , GITARI J. N. 
Published: February 2008

SUMMARYThe growth and development of Oxalis latifolia was assessed on outdoor‐grown potted plants raised from bulbs. Three main phases of growth appeared to be correlated with major physiological developments in the aerial and subterranean organs. Establishment (weeks 1 – 5) was characterised by a slow gain in plant dry weight accompanied by high relative growth rate (RGR) values for individual plant organs. The second phase of growth (weeks 6 – 12) was reproductive, as stolons grew and initiated bulbils at the apices. Bulbils had the capacity to produce their own shoot system and ultimately some primary bulbils supported secondary bulbils. Dry matter accumulation was in the order: bulbils > peduncles > leaves > petioles > stolons = roots > parent bulb. The RGR of individual plant organs declined together with the net assimilation (NAR) rates and the leaf area ratio of the shoots during the reproductive phase and beyond into the senescence phase (week 13 onwards). The results are discussed in relation to the problem of achieving weed control via cultural and herbicide treatments.
A rapid non‐destructive technique for screening carrot seedlings for resistance to carrot fly damage
Authors: COLE ROSEMARY A. , ROLLASON S. A. , MORGAN A. , GILCHRIST J. , BAKER S. A. , SPRINGER P. 
Published: February 2008

SUMMARYA technique based on fluorescence of carrot root tissues has been devised to enable large numbers of accessions to be screened for resistance to carrot fly using an epi‐fluorescence microscope. The technique is non‐destructive, and has been partly automated to assess at least 400 seedlings/hour. A data‐capture and handling package provides prompt summarising and print‐out of the results.
Competition between grass and clover in spring as affected by nitrogen fertiliser
Authors: WOLEDGE JANE 
Published: February 2008

SUMMARYDetailed measurements of irrigated ryegrass/white clover swards growing without interruption, with or without nitrogen fertiliser in spring, showed that the relative growth rate of clover was as great as that of grass, in the + N sward, and considerably greater than grass, in the – N sward. Clover leaves were not overtopped by grass leaves. Indeed, in both swards, clover had a greater proportion of its leaf lamina area in the upper, well lit, layers of the canopy than grass did. Consequently, clover had a greater mean rate of leaf photosynthesis in situ in the sward than grass. Clover's advantage in photosynthetic rate per leaf area was offset to some extent by its smaller ratio of leaf area to total above‐ground dry weight than grass.The consequences of these results for our understanding of competition between grass and clover in mixed swards are discussed.
Effects of temperature and water potential on the germination of muskmelon cultivars
Authors: DUNLAP J. R. 
Published: February 2008

SUMMARYThe rate and final germination of four muskmelon cultivars (Cucumis melo) were examined in response to incubation temperatures of 20, 26 and 32°C. Germination was also characterised at 26°C pr 32°C over a range of water potentials from 0 to ‐ 1000 kPa achieved with solutions of polyethylene glycol. The germination of one cultivar, TAM‐Uvalde, was consistently slower at 20°C than at 26°C or 32°C. The other three cultivars, Perlita, TAM‐Dew and Greenflesh, were inhibited by incubation at 32°C. However, the germination responses of cvs Perlita, TAM‐Dew and Greenflesh at 26°C or 32°C improved as water potentials were reduced from 0 to – 200 or – 400 kPa. Cv. TAM‐Uvalde was extremely sensitive to water stress and failed to germinate at water potentials below – 600 kPa when incubated at 26°C. The inhibition of germination at low water potentials was partially reversed in all cultivars by increasing the incubation temperature from 26°C to 32°C. It is suggested that the inhibition of germination at 0 kPa (distilled water) was due to a seed coat‐mediated barrier to oxygen that could be reversed by removal of the seed coat or exposure to an oxygen‐enriched atmosphere.