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Laboratory Procedures
The week after collection, the samples were analyzed for fungus extension. From the reaction zones, phloem pieces
were cut with a sterile razor blade at 5 mm intervals upwards and downwards from the inoculation points beyond the visible
reaction zone. The sample pieces were placed on petri dishes with malt agar medium and incubated at 25°C for 1 week.
Positive and negative records of L. wingfieldii were noted. Sapwood samples were handled the same way, except that
sampling took place in the radial direction. The maximum extension of the sapwood reaction zone was also measured
radially.
Data Handling and Statistics
All caiculations were done with the SAS statistical package. Preliminary analyses of vertical reaction zone lengths
and fungal growth revealed no differences between the vertical extension of reaction or fungal zones upwards and downwards
from the inoculation points regardless of the treatment (Student's t-test). Neither were there any differences between
reaction or fungal zones from different inoculation rings of the same treatment. Hence, we pooled data within the same tree,
and used tree-wise treatment means (based on 3 lesions or less in some cases with missing data) as calculation units.
Treatment means were tested using one-way analysis of variance followed by Tukey's test for multiple comparisons.
Two-way analysis of variance was also employed, as were pair-wise and standard t-tests, depending on the situation. Interdependency
between different variables was explored by regression analyses.
Reaction Zone Length
Phloem
Total length of the reaction zone varied significantly between provenances and between treatments (Fig. 1). In
Sweden, local provenances generally exhibited longer reaction zones than foreign provenances at 6 and 24 weeks. The
opposite tendency however, was visible in France at 6 weeks, where the longest reaction zones were observed in the southern
foreign provenances, particularly the Spanish and Serbian provenances, while the shortest reaction zones belonged to the
local provenances. At Remningstorp, lodgepole pine exhibited shorter reaction zones than all provenances of Scots pine after
3 and6 weeks. Despite existing differences between provenances, no systematic trends (e.g., latitudinal) in reaction zone
lengths could be detected.
At Remningstorp, reactions to the two strains of L. wingfieldii were similar but, at Nogent-sur-Vernisson, the French
strain caused a more extensive reaction zone than did the Swedish strain (Fig. 1 and 2). In both countries, reaction zones
resulting from fungal inoculations were longer than reaction zones to the controls, but the latter were clearly longer in France
than in Sweden. The correlation of the reaction zone length to the fungus increased more rapidly and to a higher level in
Sweden than in France (Fig. 2). A plateau was generally reached after 6 weeks, except for the French fungus strain in France
where the reaction zones still expanded after 6 weeks. A few provenances, however, did not fit with that description (Fig. 1).
Few of the provenances studied occurred at both study sites. The pair "Kal" (France) and "Vas" (Sweden) originates
from the same region and altitude in southeastern Sweden, and should hence be comparable. We can also assume that the
Finnish "Fin" (France) and Carelian "O1o" (Sweden) as well as the pairs from Scotland, Poland, and Germany are fairly
similar. However, a closer examination of these pairs of provenances does not disclose any deviations from the general
results given above.
Fungal Growth
Total vertical fungal expansion varied significantly between provenances only for the 6 week sampling date (Fig. 3).
At Nogent-sur-Vernisson, fungal growth was the most expanded in the southern, foreign provenance "Seg", and the least
expanded in the French provenances, particularly the Pyrenean one. At Remningstorp, fungal growth was the most expanded
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