摘要:

SummaryThe isolation frequency ofGremmeniella abietinawas measured from asymptomatic 4‐year‐old Scots‐pine seedlings. The seedlings had been subjected to simulated sulphuric deposition (pH 3.1 or 4.1) or control treatments (irrigation with spring water (pH 6), or no irrigation) during the three previous growing seasons. The seedlings were planted in soil originating from two localities with different backround levels of copper (Cu) and nickel (Ni), and the soil was further amended with Cu (63.3 mg/1 of soil) and Ni (20.5 mg/1 of soil), or a combination of the two. The seedlings were inoculated with conidia ofG. abietinaduring their third growing season in the field. Asymptomatic infections ofG. abietinawere recovered frequently from seedlings that had received water irrigation. The addition of sulphuric acid to the irrigation water, and/or the lowered pH (pH 3.1 and 4.1) resulting from this addition, mitigated the effect of water application. The effect of Ni‐treatment on the recovery ofG. abietinadepended on the irrigation treatment; with no irrigation, Ni‐treatment increased isolation frequency, but, in irrigated seedlings the response was the opposite. Only 10.6% of the seedlings had symptoms caused byG. abietina; most of the seedlings had become infected before the application of the various t

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1995.tb01066.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryGremmeniella abietinadamage was studied at stand and tree level on the Kola Peninsula and in northern Finland. At stand level, damage was recorded in four areas in Finland, while only individual damaged trees were found in Russia. According to the results of branch analysis, there was no sign of endemic epidemics in any of the areas. There was a significant negative correlation between the averageG. abietinadamage and modelled SO2deposition and temperature sum along the gradient. The results suggest thatG. abietinais distributed all over northern Finland and the Kola Peninsula in natural stands of Scots pine, and that the direct effect of SO2deposition from the Monchegorsk nickel smelter on the damage may be minimal.

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1995.tb01067.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummarySeedlings ofPinus sylvestris, P. nigra ssp. laricio, andP. mugovarsmughus, rostrataandpumiliowere inoculated at their cotyledon stage with aeciospores ofPeridermium pinifrom north‐east Scotland. Infection was determined by the presence of both mycelia and haustoria in free‐hand or paraffin sections. In the second growing season, infected seedlings showed symptoms such as stem‐swelling, development of spermogonia and aecia, and death. In a second experiment, youngP. sylvestrisseedlings from seven seed sources collected in Great Britain were inoculated and the infection were examined after 6 weeks. In the samples of 50 seedlings from each source, 30–70% seedlings were i

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1995.tb01068.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryThe callus‐fungal method was employed to test the response toC. flaccidumof the highly susceptibleP. nigravar.laricioand the resistantP. sylvestris, and to ascertain whether results obtained with this method matchedin plantaobservations. Calli were inoculated with axenie cultures ofC. flaccidumobtained by incubating basidiospores on modified Schenk and Hildebrandt medium. Several parameters were evaluated. Colony growth was more rapid onP. nigravar.laricio. Colonies were dense onP. nigravar.laricio, but sparse onP. sylvestris. Aerial hyphae growth was abundant onP. nigravar.laricio, but less frequent onP. sylvestris. Hyphal branching began after 18 h onP. nigravar.laricioand after 45 h onP. sylvestris. Necrosis of the host cells set in after 24 h onP. nigravar.laricio, and after 70 h onP. sylvestris. The number of cells with plasmolysis was much larger inP. nigravar.lariciothan inP. sylvestris. These results were consistent with the known resistance of the two species on whole plant

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1995.tb01069.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryFungi were isolated from the cone scales and seeds of Scots pine using plating on malt‐extract agar and/or the standard blotter method in a Jacobsen's apparatus.Alternaria alternata, Epicoccum purpurascensandUlocladium atrumwere isolated from damping‐off seedlings germinating on agar or filter paper, but, in pathogenicity tests with peat‐sand (1:3) growth substrate, they were not pathogenic. All theFusariumspecies isolated were pathogenic in growth substrate. SomeF. avenaceumcolonies formed no aerial hyphae and they proved to be a mixed culture of the fungus, a fluorescentPseudomonassp., and a gram‐negative bacterium. The bacterial associates appeared to increase the pathogenicity ofF. avenaceum. All the micro‐organisms tested were more pathogenic in sterilized than in unsterilized peat‐san

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1995.tb01070.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryThe presence of basidiomes of wood‐decay fungi on living lenga (Nothofagus pumilio) was investigated in seven forest stands in Patagonia (Argentinia). The following species accounted for 85% of the rots:Postia pelliculosa, Phellinus andinopatagonicus, Piptoporus portentosus, Aurantioporus albidus, andSerpula himantoides. Ph. andinopatagonicusandA. albiduscause characteristic white rots, while the other tree species cause unspecific, cubical brown rots.S. himantoideswas associated with cords among the decayed wood fragments. One stand was investigated in detail. The volume of decayed timber on this plot was 75%.Postia pelliculosaandPh. andinopatagonicusprobably infected the trees through the roots as well as through the canopy, and accounted for 70% of the wood‐rots.Piptoporus portentosusprobably infected only through the canopy, whileA. albidusandS. himantoidesdid so through the roots. Only 12% of the trees showed no decay. From trees with decay, 36% were attacked by one fungal species, 35% by two spec

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1995.tb01071.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SummaryThe inhibiting effect of sugar‐beet chitinase, a defence enzyme in plants, on the growth of the fungiHeterobasidion annosumandGremmeniella abietinawas examined. The enzyme inhibited the growth ofH. annosum, but had no effect onG. abietina. The role of hydrolytic enzymes in defence is briefly discusse

ISSN:0300-1237    

DOI:10.1111/j.1439-0329.1995.tb01072.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY