摘要:

AbstractXylem fluids from white lupin cv. Neuland, susceptible to wilt causes byFusarium oxysporumf. sp.lupini, promoted germination of conidia and chlamydospores of he pathogen, and the production of micro‐conidia, to a greater extent than did xylem fluids from the resistant cv. Primorskij No sugars, organic acids or phenolic compounds were detected in the xylem fluids, but a number of amino acids were found, and the concentration of some differed in xylem fluids from the two cultivars; on the whole, concentrations were greater in the susceptible cv. Neuland. Synthetic amino acids were supplied to the fungusin vitroand both stimulatory and inhibitory effects (according to the compound and its concentration) were noted upon the germination of conidia and chlamydospores and on mycelial growth and the production of conidia. The role of amino acids and other compounds in the susceptibility of white lupin to wilt is discusse

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00760.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractChicory yellow mottle virus, ringspot strain (CYMV‐RS), supports the replication of a low molecular weight RNA (0.17 × 106daltons) associated with CYMV‐T (type stain).Competition hybridization experiments revealed lack or nucleotide sequence homology between 0.17 × 106mol. wt. RNA (Sat RNA) and CYMV‐RS genomic RNAs, and partial homology (33 %) with CYMV‐T genomic RNAs. However, such apparent partial homology can be due to contamination of CYMV‐T genomic RNAs with a multimeric form of Sat RNA having a similar molecular weight. On this account the hypothesis that CYMV‐T Sat RNA is a true satellite RNA be

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00761.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractLipopolysaccharides (pr‐LPS) and extracellular polysaccharides (EPS) were prepated fromin vitro‐cultures of phytopathogenic pseudomonads (Pseudomonas phaseolicolarace 1 and race 2,P. aptata, P. tabaci) and purified. The preparations were dissolved in water (0.25–2.5 mg/ml) in infiltrated withP. aptataorP. pisi(9 × 107cells/ml). Whereas the hypersensitive rzaction againstP. aptataandP. pisiwas inhibited by C.25 mg/ml of pr‐LPS in most of tae cases, the same concentration of EPS caused only partial or no inhibition. However, at 2.5 mg/ml most of the EPS‐preparations caused a complete inhibition. The LPS and EPS‐preparations ofP. phaseolicolarace 1 caused less inhibition than tho

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00762.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractInjection of cucumber cotyledons with polyacrylic acid (PA), acetylsalicylic acid (ASA) and salicylic acid (SA) induced resistance to inoculations withColletrichum Iagenariumwhen inoculation followed injection by 96 h but not by 24 h. Size and number of lesions were greatly decreased. Resistance was greatest in injected cotyledons but was also pronounced in non‐injected halves of cotyledons and occasionally in first or second leaves.Incorporation of PA, ASA and SA into liquid shake cultures did not significantly affect growth of the pathogen.Gel electrophoresis of soluble proteins extracted from cotyledons showed that induction of resistance was not accompanied by the appearance of novel soluble protein

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00763.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractBacterial stem rot, due toErwinia chrysanthemi, is a serious problem in ornamental crop protection, e.g. inDieffenbachia. It was our aim to compare the effect of the synthetic compound CGA 78039 and streptomycin sulphate on the suppression of stem rot disease inDieffenbachia. Different treatments were applied under natural and artificial infection pressures. Pretreatment of the mother plants with CGA 78039, followed by dipping of the cuttings overnight in the same solution before potting and five subsequent weekly foliar sprays during growth reduced the expression of stem rot inDieffenbachiasignificantly.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00764.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractWeekly estimates of numbers ofPseudocercosporella herpotrichoidesconidia on naturally infected wheat straw, made from February to July 1982, showed there were most conidia (8.1 × 106per straw) in February and least (1.9 × 104per straw) at the end of June. The viability of these spores remained high throughout this period, with an average of 85 % germination after 24 h.After removal of spores produced in the field, straws were incubated at 5, 10, 15, 20 or 25°C and subsequent sporulation assessed after 3 or 5 weeks. The optimum temperature for spore production was 5°C and very few spores were produced at 25°C. There was no difference in viability between spores produced at different temperatures.Wheat seedlings placed amongst infected straw collected and retained spores on the upper and lower surfaces of all leaf blades and on outer leaf sheaths. Both naturally dispersed spores and spores sprayed on to plants were not removed by subsequent rainfall.When wheat seedlings were inoculated between the coleoptile and outer leaf sheath with different numbers ofP. herpotrichoidesspores, lesion development was most rapid in seedlings inoculated with the greatest numbers of spores. However, after incubation for 12 weeks visible lesions were present on all plants inoculated with>c. 10 sp

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00765.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractLeaf tissue from plants infected with northern cereal mosaic virus (NCMV) and wheat rosette stunt virus (WRSV) was extracted with a buffer containing a non‐ionic detergent. The extracts were tested by double immunodiffusion test for comparing the G protein antigens and by immunosorbent electron microscopy with decoration for comparing the nucleocapsid antigens. The heterologous reactions could not be distinguished from the homologous, thus indicating close relationship or identity of the two viruse

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00766.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractIsolates ofErwinia carotovorasub sp.atroseptica, E. carotovorasub sp.carotovoraandE. chrysanthemiwere compared for their ability to rot potato tubers and to elicit the accumulation of phytoalexins. With three incubation temperatures (15, 22 and 30°C) tubers were more susceptible at higher temperatures and mean rot weights were inversely correlated with mean rishitin concentrations. However, within treatment variation between tubers in the extent of rotting was not correlated with rishitin concentration suggesting that other factor(s) also affect resistance. Phytoalexins, including 15‐dihydrolubimin, 3‐hydroxylubimin, phytuberin and solavetivone, were measured by high pressure liquid chromatography using a silica co

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00767.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe best results in attempts to purify beet necrotic yellow vein virus were obtained with a slightly modified Triton × 100 method originally described by Hullet al.(1976) for cauliflower mosaic virus. Immunosorbent electronmicroscopy (ISEM), the double antibody sandwich form of enzyme‐linked immunosorbent assay (ELISA) and electro‐blot immunoassay (EBIA) yielded similar result when sugar beets were tested for the presence of virus. ISEM and EBIA ofer the advantage that in addition to serology a second parameter, i.e. either particle morphology or coat protein molecular weight, is used to identify the virus. Specific and possibly nonspecific reactions are thus more readily distinguished and antisera can be used which may still contain some antibodies to normal plant constituents. However, with these methods only a limited number of samples can be studied at a time, therefore ELISA is presently the method of choice for large scale routine testing.ZusammenfassungBeet necrotic yellow vein virus: Reindarstellung, Herstellung von Antiseren Und Nachweis Mit Hilfe von ELISA, Immunosorbent electronmicroscoy und Electro‐Blot ImmunoassayBei Versuchen Zur Reindarstellung des beet necrotic yellow vein virus wurden die besten Ergebnisse mit einer leicht modifiziertem Triton × 100 Methode erzielt, die ursprüng für das cauliflower mosaic virus von Hullet al.(1976) entwickelt worden war. Immunosorbent electronmicroscopy (ISEM), double antibody‐sandwid, ELISA und electro‐blot immunoassay (EBIA) ergaben ähnliche Resultate bei der Unteuchung von Zuckerrübenwurzelproben. ISEM und EBIA haben den Vorteil, daß neber der scrolognchen Reaktivität noch ein zweites Merkmal zum Nachweis des Virus eingeserz wird, bei ISEM die Partikelmorphologie und bei EBIA das Molekulargewicht des Hüllprodtim badurda kännen spezifische und eventuell unspezifische Reaktionen besser unterschreden werden und es können Antiseten verwendet werden, die noch Antikörper gegen normale Pflauzenbestandteile enthalten. Da mit diesen Methoden jedoch nur eine begrenzte Anzabl von Probcagleichzeitig untersucht werden kann, ist für Massenuntersuchungen ELIS

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00768.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe survival in the field ofP. cichoriiwas studied using a twice‐marked mutant resistant to 200 μg/ml of both nalidixic acid and rifampicin. The mutant was used to contaminate head lettuce cv. Verpia in an experimental field. The survival ofP. cichoriiwas evaluated on the basis of the results of quantitative reisolations, on appropriate selective medium, form asymptomatic leaves, nerval lesions, surface debris and soil after the debris had been incorporated. The mutant was found on symptomless leaves up to 63 days after contamination. It cannot be concluded thatP. cichoriiis a resident epiphyte because the mutant was already found associated with nerval lesions only 28 days after field contamination.The mutant was successfully reisolated from the lettuce debris, but not form the soil after its incorporation. 115 days after incorporation of the debris the mutant was found associated with nerval lesions in lettuces planted the following year in the same field.The means by whichP. cichoriisurvives are discussed. Experimental evidence indicates that it survives in the soil, associated with infected lettuce debris, but that the population level was below the sensitivity threshold of the detection meth

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1984.tb00769.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY