摘要:

AbstractBotrytis cinereaspores suspended in 0.28 M glucose solution caused limited lesions on clover leaves, on which the clover phytoalexins maackiain and medicarpin accumulated to 1028 μg and 856 μg/g fresh wt respectively after 4 days incubation. During this time, little or none of the phytoalexin degradation products were detected. On the other hand,B. cinereaspores in sucrose casamino acids (SCA) liquid medium caused larger lesions than spores in glucose, and less maackiain and medicarpin (298 μg and 95 μg/g fresh wt respectively) and high concentrations of the degradation products were detected.B. cinereamycelium in SCA also caused large lesions and both the phytoalexins and their degradation products were detected.,Sclerotinia laxaspores in 0.28 M glucose or its mycelium in SCA liquid medium did not cause any lesions apart from a minute necrotic fleck, and although phytoalexins were recovered from leaves inoculated with spores (67 μg and 78 μg/g fresh weight of maackiain and medicarpin respectively after 4 days) and leaves inoculated with mycelium (150 μg and 167 μg/g fresh wt maackiain and medicarpin respectively after 3 days), no phytoalexin degradation products were detected. The implications of, these results in understanding the interrelationship between nutrients, pathogenicity and phytoalexin metabolism are di

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00911.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe serological and lysotypical properties of 28 strains ofX. albilineansoriginating from different geographic zones were analysed. Using the indirect immunofluorescence technique with 3 antiX. albilineansimmunsera, the existence of three serovars was shown. The isolation of lytic bacteriophages from the soil enabled us to classify the bacterial strains into 6 lysovars. A correspondance between serovars and lysovars was revealed. These results show a variability of theX. albilineansspecies, and enable an analysis of the structure of its populations to be proposed, especially that of Tropical Africa.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00912.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAspects of the biology ofGliocladium virensand parasitism of sclerotia ofSclerotinia sclerotiorumin soil were studied.G. virensparasitized and decayed sclerotia ofS. sclerotiorum, S. minor, Botrytis cinerea, Sclerotium, rolfsiiandMacrophomina phaseolinaon laboratory media and caused a reduction in survival of sclerotia ofS. sclerotiorumin soil. It was active over a broad range of soil moisture levels and over the entire agricultural soil pH range. The main factor limiting its use as a biological control agent was its temperature requirements.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00913.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe systemic migration ofXanthomonas campestrispv.pruni (Xcp)through vascular bundles of leaves and twigs of plum was investigated. A rifampicin‐resistant strain ofXcpwas inoculated into leaves located midway from the tip of new green twigs of Golden King plum trees in a glasshouse. High numbers of the pathogen were recovered 4 and 8 weeks after inoculation from sections of uninoculated and symptomless veins, petioles, and twig tissue. Symptoms of bacterial spot developedwithin 8 weeks on main and secondary veins of uninoculated leaves located as far as 13 cm from the inoculated leaf on the same twig. Weekly isolation indicated the constant presence ofXcpin apparently unaffected shields of twig tissue obtained from a naturally infected Golden King orchard.Xcpapparently enters plum twigs through veins of infected leaves and migrates systemically through twigs to leave

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00914.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractInoculation of pepper seeds with the leaf pathogenXanthomonas campestrispv.vesicatoriainhibited pepper germination. The inhibitory effect, which was stronger in non‐sterilized light textured soils, decreased with time, and after 20, days or more, there was no difference between inoculated and non‐inoculated seeds. Inhibitory substance(s) within the cytoplasmatic fraction of pathogen cells inhibited the germination of non‐host tomato seeds. No relationship between pathogenicity to pepper leaves and inhibition of pepper seed germination was detected. The inhibitory substance(s) was found in two out of fourX. campestrispv.vesicatoriastrains. Heat‐killed bacteria suppressed growth of pepper but not tomato seedlings. It is, therefore, suggested that the inhibition of seed germination and the decrease in root development are different modes ofX. campestrispv.vesicatoriapathogenesis toward pepper

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00915.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractBy means of a modified agar‐ring method, the antibiotic efficacy of 300 isolates of actinomycetes, obtained from soil samples from Turkey, against six different test fungi was investigated. A wide range in their degree of sensitivity was evident. WhereasSclerotinia sclerotiorumwas completely inhibited by more than 90 % of the tested isolates,Rhizoctonia solaniandAlternaria alternatawere suppressed by only 17 and 14 %, respectively;Pythium debaryanum, Cochliobulus sativ, usandMacrophomina phaseolinaheld an intermediate position. Isolates which completely prevented the growth ofRhizoctonia solaniandAlternaria alternata, were usually also highly effective against the other test fungi. Possible conclusions which may be drawn from these results are discusse

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00916.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractWater samples were collected from some rivers of Southern Italy whose water is normally used for irrigation and checked for the presence of plant viruses. The assayes were carried out by centrifuging at 5000x g one liter of water, resuspending the sediments in phosphate buffer and testing their infectivities onChenopodium quinoaWilld. It was possible to isolate tobacco mosaic virus, cucumber mosaic virus and two more viruses not identified yet.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00917.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractPeriods of conditioning in soil reduced the length of the resting period needed before sclerotia ofSclerotinia sclerotiorumcould germinate to form apothecia. Curves for germination of sclerotia were fitted by a form of the log‐logistic equation and from this equation the time taken for 50% germination (x50) was calculated. These x50values were used as the basis for comparing germinability of sclerotia collected from infected sunflower plants and others conditioned in soil, or moist vermiculite for various times. Sclerotia from sunflower roots germinated sooner than those from the stem cavities. Germinability increased with the length of the conditioning period. Conditioning in soil was more effective than in moist vermiculit

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00918.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper presents some aspects of latex coagulation inside latice vessels of roots ofHevea brasiliensisinfected by two fungi:Rigidoporus lignosusandPhellinus noxius.Three stages are described in latex coagulation: the phase of latex destabilisation characterized by the bursting of vacuoles and lysosomes membranes; the phase of latex coagulation characterized by the fusion of rubber particles and the disorganization of the cytoplasm; the formation of shots of rubber clumps indicating the final stage of coagulation.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00919.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA specific reaction has been observed in immunodiffusion, using the supernatant obtained after centrifugation ofE. amylovoraphenol treated cells. This reaction occurred for all theE. amylovorastrains examined and could be distinguished from all other reactions occurring with different species of Erwinia. We called the product inducing the specific reaction: Specific Antigenic Fraction or SAF.The immunological and chemical characteristics of SAF have been compared with other extractable products from the bacteria (LPS, ‘O'Ag), from the culture media (EPSc) and from the ooze (EPSo). This revealed that SAF is lipopolysaccharide in nature and that the specific antigen(s) involved would be on a polysaccharidic fractio

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1986.tb00920.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY