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1.
The formation and maturing of the large tree type Gremmeniella abietina var. abietina fruiting bodies and their sporulation were investigated for 3 years on Scots pine (Pinus sylvestris) in northern Finland. This was done by monthly assessment of shoots in the field and in the laboratory. Infection caused by G. abietina var. abietina was dated on Scots pine by monthly covering with pollination bags and exposing branches during the growing season. Pycnidia appeared between August and September, 1 year after infection, and they started to release conidia between late June and early July, 2 years after infection. Fresh pycnidia and microconidia were formed during the following August and September in the infected shoots. The causal large tree type of G. abietina var. abietina did not produce apothecia on branches within 3 years of infection. Monthly covering and exposing branches showed that infection took place mainly between June and July. 相似文献
2.
Conidia of Gremmeniella abietina infected and caused disease symptoms in annual shoots of both Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) seedlings. In Norway spruce shoots the infection remained largely latent, with only a few seedlings showing symptoms. Mycelial growth inside the shoots was faster in Scots pine than in Norway spruce and was favoured by low temperature in both hosts. The shoots of Norway spruce seedlings had higher endophyte populations than those of Scots pine, and the populations were decreased by low temperatures. Reductions in the normal epiphytic or endophytic flora by acid mist treatments seemed to favour the development of G. abietina. 相似文献
3.
Elizabeth A. B. Aitken 《Forest Pathology》1993,23(3):153-162
G. abietina causes severe dieback in pole-stage stands of Scots pine in Britain. The susceptibility of ll provenances of Scots pine and of three other conifer species was tested by inoculations. Significant differences in susceptibility were found amongst Scots pine provenances, with those originating from a native Scottish pinewood at Loch Maree showing the highest levels of disease. Corsican pine was shown to be the most susceptible species tested although sporulation was greatest on Scots pine. Norway spruce was also shown to be susceptible when inoculated late in the growing season. Infection in lodgepole pine was negligible. High levels of β-phellandrene were tentatively linked with resistance among trees in a single stand of Scots pine. 相似文献
4.
Gremmeniella abietina damage 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 average G. abietina damage and modelled SO2 deposition and temperature sum along the gradient. The results suggest that G. abietina is distributed all over northern Finland and the Kola Peninsula in natural stands of Scots pine, and that the direct effect of SO2 deposition from the Monchegorsk nickel smelter on the damage may be minimal. 相似文献
5.
Scots pine (Pinus sylvestris) seedlings were planted in a nursery bed 20 cm thick. The substrate had been removed from an illuvial horizon in the soil underlying a stand of Scots pine in Finland, which had suffered from severe infection by Gremmeniella abietina. The seedlings were irrigated for 3 years, applying three pH levels (2.5, 3.5, and 4.5) using sulphuric acid, nitric acid, and a 3:1 mixture of sulphuric and nitric acid. The pH of the pure water used in the control treatment was 6.1–6.4. The seedlings were inoculated with the conidiospores of G. abietina to find out their susceptibility to infection with the Scleroderris canker disease. Because to the adequacy of its buffering capacity, the soil was observed to become more acidic only in the treatments at pH 2.5. The concentrations of extractable Ca and Mg cations decreased while the concentration of Al and Fe increased with soil acidification during the 3-year experiment. Acidification did not increase the susceptibility of Scots pine to infection by the Scleroderris canker. Seedling growth was at its maximum in the acidification treatments where most nitrogen was added. 相似文献
6.
The interactions between Gremmeniella abietina and either Sclerophoma pythiophila or Cenangium ferruginosum, fungi frequently isolated from diseased twigs along with G. abietina, were studied under laboratory (dual cultures) and greenhouse conditions (double‐inoculations). Virulence of each species was also evaluated in greenhouse experiments by means of single‐inoculations. In vitro interactions were assessed on Petri dishes containing malt agar with pine needle extract, and greenhouse experiments were performed on 1‐year‐old Pinus halepensis seedlings. In vitro growth of G. abietina was inhibited by both fungi when grown in dual culture. In single‐inoculations, G. abietina caused the greatest necrosis length on P. halepensis seedlings, followed by S. pythiophila, whereas C. ferruginosum did not cause significant necrosis. In double‐inoculations, C. ferruginosum was able to reduce the length of necrosis caused by G. abietina on the P. halepensis seedlings. In contrast, necrosis length was greater in seedlings inoculated with both S. pythiophila and G. abietina than in those inoculated with G. abietina alone. Therefore, S. pythiophila seems to play a role in disease expression caused by G. abietina on P. halepensis in Spain. 相似文献
7.
《Scandinavian Journal of Forest Research》2012,27(1-4):256-263
The role of stand and site characteristics in a 50‐year‐old, sowed Scots pine (Pinus sylvestris L.) stand on the decline of Scots pine caused by Gremmeniella abietina was studied. Treewise damage of Scots pine was modelled using stand and site variables and stepwise regression analysis. The significant variables included in the model were stand elevation from the main cold air centre and the pH of the humus layer, while the other less significant variables were the number of stems per hectare of Scots pine and Norway spruce, content of Cu and Ni in the humus layer, and the thickness of the humus layer and the A2 horizon. The studied variables excluded from the model were the number of broad‐leaved trees per hectare, Al and Pb contents in the humus layer, and Al, Cu, Pb and Ni contents in the A2 horizon. The results strongly suggest that the vicinity of water as well as local depressions act as vulnerable sites for Scots pine and the said vulnerability is enhanced by increased pH of the humus layer. 相似文献
8.
Interactions between callus cultures of Pinus sylvestris and pine fungi with different trophic properties 
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下载免费PDF全文 Fungal virulence may be studied using tissues cultures of host plants in dual cultures in vitro, enabling analyses of interactions with undifferentiated cells of their host plants. Three genotypes of Pinus sylvestris callus, initiated by somatic embryogenesis, were used for establishing dual cultures with fungi pathogenic, endophytic or saprotrophic on pine needles or shoots. Fungal growth towards the plant callus tissue differed, depending on the life strategy of the fungus. The pathogen Gremmeniella abietina proved the slowest colonizer of callus whereas the saprotrophic Phacidium lacerum was the fastest. Gremmeniella abietina partially overgrew the callus, causing extensive necrosis and death within 10 days after inoculation. Anthostomella formosa, an endophyte of pines, did not cause evident symptoms of callus degradation: after 10 days of dual culture, the callus cells remained greenish and at least 50% of cells were alive. In dual cultures Ph. lacerum, callus remained alive until the end of the experiment, maintaining a white‐creamy colour with a loose cell structure. Electrophoresis of protein extracts from the callus showed the presence of additional bands of 25–35 kDa only in host tissues challenged with the pathogen G. abietina, possibly indicating the production of pathogenesis‐related proteins. This work has shown that pine callus does not respond equally to challenge with different fungal isolates. In general, one‐third of the isolates of each fungus examined showed greater virulence compared to other isolates. 相似文献
9.
Inoculation experiments were performed in order to evaluate the virulence of Gremmeniella abietina isolates from Spain on the main pine species planted in the Iberian Peninsula, as well as the influence of seedling age on this virulence. Two different experiments were carried out with four isolates of G. abietina from Spain. The greenhouse experiments consisted of seedling inoculations. One‐ and 2‐year‐old seedlings of the following five pine species were used: Pinus halepensis, Pinus pinea, Pinus pinaster, Pinus sylvestris and Pinus uncinata; also, 1‐year‐old seedlings of P. nigra were inoculated. The relative necrosis length (RNL) caused by the pathogen after 130 days was used as a response variable. The laboratory experiments were performed on 2‐ to 6‐year‐old internodes of the above pine species excluding P. uncinata. The necrosis length after 6 weeks of incubation was measured. The results have shown that all G. abietina isolates were pathogens on seedlings of these six pine species and seedlings of P. halepensis were consistently the most susceptible ones, although it is important to take into account that all the isolates used in the present work were isolated from P. halepensis, the only pine species in Spain where G. abietina has been recovered up to now. The susceptibility of the other pine species depended on the age of the seedlings. 相似文献
10.
The aim of this study was to investigate the differences in infections caused by Agrobacterium tumefaciens in a conifer, Scots pine (Pinus sylvestris), and in a non-host deciduous species, silver birch (Betula pendula). All the Agrobacterium tumefaciens strains tested caused crown-gall formation in both tree species, but the infection rates varied remarkably. In Scots pine, the development of galls was rare, and slower than in silver birch. Inoculation into the base of the stem were the most successful in gall induction. Silver-birch galls were large, often surrounding the whole stem, in contrast to Scots pine galls, which were characterized by their small size and neck-like connection with the host plant. In silver birch, no other morphological changes could be seen. In Scots pine, abnormal phenotypes with proliferating short shoots above the galls were observed during the second and third growing season. The results indicate that, of the two non-host tree species, the deciduous one, silver birch, is more susceptible to an A. tumefaciens infection than the conifer, Scots pine. The matrix for A. tumefaciens infection in silver birch differs from that in Scots pine, since the terpene compounds of Scots pine seem either to kill the agrobacteria or to suppress their growth. The differences between the species could be partly caused by their difference in sensitivity to phytohormones. These features reflect evolutionary incompatibility between A. tumefaciens and a gymnosperm. 相似文献
11.
R.‐L. Petäistö 《Forest Pathology》2008,38(1):1-15
First‐ and second‐year containerized Norway spruce seedlings were inoculated with conidia of type A (large tree type) and type B (small tree type) of Gremmeniella abietina var. abietina at different times during the summer. The appearance of symptoms after artificial inoculation and natural infection on spruce seedlings were recorded the following spring and compared with the disease symptoms on Scots pine seedlings. The proportion of diseased seedlings after inoculation reached as high as 80%. The susceptible period during the summer began later on the first‐year seedlings than on the second‐year seedlings, and was similar for the pine seedlings. Susceptibility of first‐year seedlings was highest in August and on second‐year seedlings in July. The accumulated temperature sum, relative humidity and height growth for first‐ and second‐year seedlings was assessed. Natural infection in 2002 caused more disease on pine than on spruce seedlings. Experimental thinning of seedlings had no effect on disease incidence. In a preliminary comparison between the ability of A and B types to cause disease in Norway spruce seedlings, type B caused more damage than type A after inoculation. However, type A caused a high disease frequency in other experiments in this study. Symptoms on Norway spruce seedlings often first occurred in the mid‐section of the shoot, and were similar to those observed on pine seedlings: needles turned brown, starting at the needle base, in the spring following inoculation. On first‐year spruce, diseased needles were shed rapidly, in contrast to a slower rate of shedding on first‐year pine seedlings. Pycnidia developed about 2 years after inoculation (on pine 1 year after inoculation). On Norway spruce seedlings the lower part of the shoot, including the lateral shoots, often remained alive. The experiments show that G. abietina can cause disease on containerized Norway spruce seedlings under nursery conditions in Finland. The coincidence of spore dispersal, seedling susceptibility and predisposing factors are important in disease development. 相似文献
12.
The effect of eight fungicides and 15 endophytes isolated from twigs of healthy Pinus halepensis trees on the growth rate of four Spanish isolates of the pathogen Gremmeniella abietina was evaluated in vitro. In the fungicide experiments, four doses of each fungicide tested were added to the growth medium. In the endophyte experiments, dual cultures endophyte‐pathogen were paired in Petri dishes. Furthermore, growth of three G. abietina isolates was evaluated on malt agar with pine needle extract amended with filtrates from cultures of endophyte E14, which produced a brownish compound apparently inhibiting G. abietina growth. The results obtained suggested that chlorothalonil and daconil were the most suitable fungicides at low doses to reduce growth of G. abietina isolates from Spain. Four of the endophytes tested in vitro showed strong antagonistic activity against G. abietina and deserve further testing in vivo. The endophyte E14 produced in vitro a brownish compound which almost completely inhibited mycelial growth of G. abietina isolates from Spain. 相似文献
13.
《Scandinavian Journal of Forest Research》2012,27(1-4):242-250
Embryogenic cultures (EC) of Scots pine (Pinus sylvestris L.) were initiated from immature embryos. Whole ovules were used as expiants. The responsive period for initiation began just after fertilization and remained throughout the development of first stages of early embryos. The main part of the embryogenic cultures were initiated by the time of cleavage polyembryony. Strong correlation was obtained between degree days and the responsive period. During subsequent years the experiments were repeated in Finland and Sweden. In all cases the responsive period for initiating embryogenic cultures was the same, about two weeks after fertilization. In 1991–1993, a total of 138 clones of elite pine trees were tested for their ability to initiate embryogenic cultures. Of these, 33% were responsive under our experimental conditions. Based on about 300 ovules per clone the number of embryogenic lines induced by the responding clones varied from 0.2% to 9.0% of the expiants. Several nutrient media were found to be suitable for initiation and proliferation of ECs. About half of the cell lines responded to abscisic acid by producing maturing embryos. The embryos reached full maturity in cultures of only a few cell lines. Some of the embryos that produced roots were planted in soil and transferred to a greenhouse. 相似文献
14.
The foliar chemistry of diseased and healthy trees was studied one growing season after severe reduction in living crown caused by Gremmeniella abietina in four young Scots pine (Pinus sylvestris) stands. Sample trees were chosen pairwise on the basis of the living crown length: a diseased tree with about 50% live crown reduction and a healthy tree in each pair. Fifteen elements were determined in the youngest healthy needles on the lateral top shoots of each sample tree. Diseased trees had higher foliar boron, manganese and sodium concentrations and lower magnesium, iron, zinc, copper, potassium, nitrogen and sulphur concentrations compared to the healthy trees. Foliar calcium, aluminium, phosphorus, carbon and hydrogen concentrations did not differ between the diseased and healthy trees, except for P and A1 in two of the stands when the stands were analysed separately. Significant correlations between the needle element concentrations and crown ratio (length of the living crown/tree height) were found especially for B (increasing B with decreasing crown ratio) and for Mg, Fe and Zn (decreasing concentrations with decreasing crown ratio). The effect of G. abietina-induced living crown reduction on tree nutrient status and the role of these mineral nutrients in the susceptibility are discussed. 相似文献
15.
《Scandinavian Journal of Forest Research》2012,27(1-4):159-163
The mycelial growth of 24 isolates of types A and B of Gremmeniella abietina (Lagerb.) Morelet, collected in northern Finland and the Kola peninsula, Russia, was studied on malt agar plus pine needle extract at 18°C and 5°C. Great variation occurred within both types, and the results suggest that several isolates per stand are needed to represent one local isolate, if responses of G. abietina mycelia are studied on artificial media. 相似文献
16.
Thirteen Finnish Gremmeniella abietina isolates of types A and B were compared for differences in their virulence. Three kinds of inoculations were made: one with conidia on young Scots pine (Pinus sylvestris) seedlings and two with mycelia on the stems and shoots of young Scots pine trees. Inoculations with conidia were carried out in August 1992 and inoculations with mycelia were carried out six times between 11 August and 20 October, 1992. The experiments were evaluated in the late spring and early summer of 1993. The results showed that there was a difference in virulence between the two types. In the conidial inoculations type A infected 34.7% and type B infected 11.0% of the inoculated seedlings. For mycelial inoculations with type A the mean canker (stems) and necrosis (shoots) lengths were 19.3 mm and 8.6 mm longer, respectively, than with type B inoculations. In shoot inoculations there also was a clear difference between the two types in the number of such inoculations where no symptoms were observed. For type B shoot inoculations there was no fungal growth in 21.5% whereas for type A inoculations the figure was only 3.7%. 相似文献
17.
Survival and vitality of Gremmeniella abietina on Pinus sylvestris slash was studied in northern Sweden during 2003 and 2004. Once a month between September 2003 and April 2004, two to three trees were cut down and debranched. Shoots with pycnidia were sampled at the felling date and then at every consecutive month. The percentage of germinated conidia from each shoot was calculated after 24, 48 and 72 h incubation. The vitality of G. abietina pycnidia in the slash remained high the whole period. Intact pycnidia were found on slash several months after the time of conidial sporulation, which indicates that new pycnidia may be produced on dead pine branches. Sampling of shoots from slash on 13‐ to 18‐month‐old clear‐cuts showed conidial germination capacity as high as in pycnidia collected in fresh slash. Due to survival of G. abietina in slash it is recommended to postpone planting of P. sylvestris seedlings in northern boreal areas to the third vegetation period after sanitary clear‐cuts. 相似文献
18.
I. M. Thomsen 《Forest Pathology》2009,39(1):56-72
The combination of temperature and precipitation during the growth season could be correlated with the occurrence of Gremmeniella abietina epidemics in Denmark. The Gremmeniella index value (GIV) is the result of the monthly rain in mm divided by average monthly temperature in centigrade (mm/°C) and it was created to facilitate easy prediction of epidemics in Denmark. The two most severe outbreaks of G. abietina in pine and other conifers in Denmark took place in 1963–64 and 1984–85, following years where low average temperatures and high precipitation in May combined with the same weather patterns in either August or September. These meteorological conditions were not fulfilled from 1874 to 1900, in which period Pinus nigra was pronounced unsuitable for Danish forestry because of recurring problems with fungal disease. However, the earlier epidemics seemed to coincide with cold and rainy weather (high GIV) in August. In addition, severity of epidemics may also depend on the presence of dense stands between 30 and 40 years of age, as high GIV in August has occurred without disease outbreak in periods with low frequency of susceptible stands. Gremmeniella abietina attacks in Denmark are initiated by the climatic conditions expressed by the Gremmeniella index value, although it does not explain the biological process behind this phenomenon. Nevertheless, the method could be useful for other regions, where epidemics of G. abietina may be related to weather. 相似文献
19.
M. Hellgren 《Forest Pathology》1995,25(3):159-168
Gremmeniella abietina isolates from Pinus contorta in northern Sweden produced, in vitro, shorter conidia with fewer septa compared with isolates from Pinus sylvestris in the southern part of the country. After mycelial inoculation of shoots with G. abietina isolates from both host species, the resulting necroses were longer in P. sylvestris than in P. contorta. Keeping seedlings in artificial mild winter climate or detaching shoots from the seedling before inoculation caused longer necroses. No host specificity in colonization was found. Isolates from P. sylvestris caused longer necroses than did isolates from P. contorta, and both types of isolates caused longer necroses in P. sylvestris than in P. contorta. The differences found between the two G. abietina populations probably reflect regional variation in the fungus. 相似文献
20.
《Scandinavian Journal of Forest Research》2012,27(4):290-291
Abstract In 2001 large areas of Pinus sylvestris L. stands in Sweden were attacked by Gremmeniella abietina (Lagerb.) Morelet. The resultant damage was assessed in five genetic field trials and one clonal seed orchard, with the aims of quantifying the genetic variation in tree responses to G. abietina, studying the genetic relationship between G. abietina susceptibility and growth traits, and examining the implications of the results for P. sylvestris breeding. A comparison of G. abietina damage between plus-tree progenies and seed stand check-lots in each of four tree classes (dominant, co-dominant, subordinated and suppressed) found no significant differences except in the suppressed tree class, where plus-tree progenies were damaged less severely than trees from the seed stands. Narrow- and broad-sense heritability for G. abietina damage traits were in the range 0.22–0.42. Genetic correlations between G. abietina damage and growth traits were weak and not significantly different from zero. The results imply that selection for growth capacity in P. sylvestris breeding programmes using plus-tree selection or field progeny tests does not increase susceptibility to G. abietina. In addition, there is scope for selecting genotypes with increased resistance if this is required in the future. 相似文献