摘要:

AbstractRibonucleic acids were extracted from needles of symptomless and damaged spruces (Piceaspp.). Trees from three locations of different altitudes in Nordrhein‐Westfalen were taken for sampling. The samples were collected from the same individual trees at different times during the growing seasons of the years 1984–1986.Small RNAs (Mr<300 000) were analyzed by a two‐dimensional gelelectrophoresis. The aim was to detect “disease associated” RNAs by a comparison of the RNA‐patterns of symptomless and damaged spruces. A RNA of about 450 nucleotides was a strong candidate, though it was found in needles of both damaged and symptomless trees. The concentration of the RNA450is dependent on the season, the needle age, and the location of the tree. In damaged trees the level of the RNA450ishigher than in symptomless trees. The RNA450was found to be an endogeneous RNA, which indicates both the developmental state of the needle, and an interference with the development by the damage already at the early level of RNA

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00972.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA nucleic acid of about 450 nucleotides, called RNA450, was extracted from needles of symptomless and damaged spruces (Picea abiesL., Karst.) and was analysed by two‐dimensional gel electrophoresis. The samples originated from 14‐years‐old spruces of two differently exposed forest sections of the same location in the Hils area. Trees of section 65 were symptomless whereas those of section 103 were retarded in their growth and had partly yellow coloured needles.A new tree was selected for each sampling. Samples were taken at monthly intervals from June 1985 to March 1986, and bimonthly from March to December 1986. The aim of the study is to find out whether the RNA450indicates the damage of trees in the Hils. The RNA450was characterized in the accompanying paper (Beutheret al.1988) as an endogeneous RNA, which is influenced in its concentration by tree damages. A comparison of the RNA patterns of needle extracts from four different needle year classes of symptomless and damaged trees led to the result that the concentration of RNA450is influenced by season, needle age, and damage. The amplitude of the seasonal changes in the RNA450level was found to be larger in younger than in older needles and is not influenced by the position of the branch. The period of metabolic activity, as observed on the level of RNA450, is markedly shorter in damaged than in symptomless trees. The usefulness of the RNA450as a diagnostic test system will be disc

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00973.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe population build‐up ofPseudomonas solanacearumin the rhizosphere, and root‐tissues of two egg plant varieties, susceptible and resistant, raised in infested soil was investigated at different stages of plant growth. There was no perceptible difference in the population build‐up of the pathogen in the non‐rhizosphere soils of both the susceptible and resistant plants. However, the soil 3 cm away from the tap root of the susceptible variety contained a higher population of the pathogen compared to the soil similarly drawn from the resistant plants. The pathogen population in the rhizosphere of the susceptible variety increased 1,000‐fold with increasing age of the plant and was highest at flowering. The rhizosphere of the resistant plant, showed only a 10‐fold increase in pathogen population. The trend was similar with the root tissue populations of the pathogen, but the differences in the root tissue populations of the resistant and susceptible plants were more pronounced. Considerable, buildup of the pathogen population in the susceptible variety was also seen in the above ground portions of the plants. Root extracts of the resistant variety had a marked inhibitory effect on the growth of t

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00974.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAnatomy and photosynthesis of grapevine leaf affected by protuberant growthGrapevine cultivated under controlled environmental conditions developed leaves affected by abaxial protuberant growth in form of raised patches in the intercostal region which were examined by SEM and porometry. Cross‐sections of freeze‐fractured raised patches without prior fixation showed an increase in the number of mesophyll cells responsible for the emergence, without superficial epidermal cracks, necrosis or deformed stomata. Leaves with wide spread symptoms appeared more shiny and curled and, showed a larger reduction in photosynthesis, by up to 76 %, than in transpiration, by up to 20 %, relative to unaffected leaves. It is concluded that this reduction in photosynthesis may be caused by increased mesophyll resistance to CO2andless light transmission. The protuberant growth was not correlated with ambient CO2concentrations ranging from 340–700 μl

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00975.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA severe leaf spot disease of cucumber caused by a pathotype ofAlternaria alternata(Fr.) Keissler was recorded recently in plastic houses in Crete. Lesions ranged in size of a pin point to over 5 cm in diameter, with necrotic tissue on most of their area and a surrounding yellow zone. The pathogen grew satisfactorily on PDA at temperatures between 5 °C–40 °C and spore germination occurred in the range less than 10 °C to over 37 °C. Optimum temperature in both cases was near 26 °C. Of,13 fungicides testedin vitro, sodium omadine, etem, dichlofluanid, captan and folpet were the most inhibitory on spore germination, and iprodione, sodium omadine and dichlofluanid on mycelial growth. Of 25 fungicides applied on two leaf cucumber plants 24 h before inoculation, maneb, etem, dichlofluanid and chlorothalonil were the most effective. When the last fungicides, plus mancozeb, were applied 24 h after inoculation only maneb was effective. In greenhouse experiments, iprodione, prochloraz‐manganese‐complex, chlorothalonil, dichlofluanid, guazatine, maneb and etem were the most effective for disease control, while mancozeb was less effective. The local cucumber cv. Knossos and the Dutch F1hybrids Evadan, Frella, Herta, Malfa, Mazourka, Pepinex 69 and Renova were all susceptible to

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00976.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA virus causing a severe disease of tomatoes in Argentina was identified as a strain of eggplant mosaic virus (EMV). It resembles the type, Abelia latent and various Andean potato latent strains of EMV in its host range and its transmissibility at allow rate byEpitrixsp. It differs from these strains, however, serologically and in some of its cytopathic effects. In serological agar gel double diffusion tests it proved to be closely related to the tomato white necrosis isolate of EMV studied by Barradas(1983) in Brazil.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00977.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA small water sample of only 60 ml from the Oker Aue canal near Braunschweig was ultracentrifuged. The resuspended pellet was rubbed onChenopodium quinoaleaves which responded with the formation of almost 200 local lesions. The virus causing these lesions was identified as carnation ringspot virus (CarRSV) by means of dot blot hybridization using random‐primed cDNAs to the viral nucleic acids and by means of serology. Northern blot analysis revealed that the two RNA species of the virus which consisted of c. 3.7 and 1.5 Kb, respectively, have little or no base sequence homology. In immunoelectrophoresis at pH 7.0 the virus migrated towards the cathode. The isometric particles were 33 nm in diameter, round to slightly angular in outline, and showed a distinct granular or knobly surface structure. Virus particles occurred in the cytoplasm, nuclei, and vacuoles of infected cells which in addition contained amorphous granules in the cytoplasm and/or proliferated endoplasmic reticulum. Heavily, affected cells were necrotized and contained large virus particle aggregates which sometimes were crystallized.CarRSV is the third carnation virus, after carnation mottle and carnation Italian ringspot viruses, which was identified in a natural wate

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00978.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe possible connection between peroxidase activity and citrus species and cultivars was investigated in relation to tolerance and susceptibility to greening disease.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00979.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe present study indicates that the peroxidase activity can be partly inhibited by gentisic acid and possibly thereby interferes with the mechanism of resistance to greening diseases of citrus.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00980.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractFor identification of cowpea viruses existing in Senegal, 180 samples collected from 4 different locations were examined. Initially agar gel diffusion tests were employed to identify the viruses present in these samples using antisera to 3 beetle‐transmitted viruses viz. CPMV, SBMV and CMeV. The results indicated the presence of SBMV in 78 samples mostly from Casamance while none of these viruses were detected in the samples collected from northern Senegal. These results were later confirmed by Enzyme‐linked Immunosorbent Assay (ELISA). This is the first report of occurrence of SBMV in Sene

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1988.tb00981.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY