Effects of disinfection and mycorrhization of substrate on development of Norway spruce (Picea abies [L.] Karst.) seedlings | Účinky dezinfekcie a mykorizácie substrátu na vývin semenáčikov smreka obyčajného (Picea abies [L.] Karst.)

In nature, roots of forest trees live in symbiosis with ectomycorrhizal (ECM) fungi that provide any advantages to trees (increased uptake of nutrients and water, production of growth hormones, protection against diseases and pathogens). Mycorrhizal symbiosis is also one of the important attributes of physiologically well developed planting stock, being enabled to withstand variable stress factors of planting sites. Root systems of secdlings grown in small nurseries placed in or near forests are naturally colonized by propagules of symbiotic fungi from sUrrounding. Cultural practices of the growing of planting stock (greenhouse, artificial substrates, frequent application of fertilizers and pesticides) and disturbed mycorrhizal status of planting sites restrict natural mycorrhizal development. In any cases, only possible opportunity to induce development of mycorrhizal symbiosis is artificial mycorrhization of roots with inoculum of selected mycorrhizal fungi. Growth substrate (peat amended with perlite, vermiculite, zeolit and NPK) was disinfected with Basamide and inoculated at sowing with vegetative alginate-bead inoculum of ectomycorrhizal fungi Tricholoma sejunctum and Gomphidius glutinosus. Experimental design was a two-way classification (substrate and fungus) arranged in a randomized complete block design. The experimental unit was the 0.07 square m plot (vessel). Two substrate treatments (disinfected and no disinfected) and four inoculation treatments (2 fungi, beads without fungus, pure substrate) set up 8 combinations of main effects. Seedlings of Norway spruce were growing in greenhouse in operational conditions. After the first growing season (in november) survival of seedlings was estimated and 15 seed1ings From each treatment and blockwere randomly selected and evaluated for ectomycorrhizal formation (% of number of individual ECM morphological types and % of all ectomycorrhizas from number of all short roots), stem height, root collar diarneter, root dry weight, shoots dry weight, total dry weight, ratio ofroot and shoot dry weights. Data were analyzed by two-way analysis of variance followed by a Tukey s test (p = 0.05) to determine treatment differences. Inoculation of substrate with vegetative-bead inoculum of ECM fungi Tricholoma sejunctum and Gomphidius glutinosus and presowing disinfection of substrate with Basamid did not perform marked differences in survival of one-year-old bareroot Norway spruce seedlings growing under greenhouse. The disinfection unequivocally suppressed a weed growth but there was no necessary to suppress pathogenic microorganisms. Disinfection of substrate had no significant effect on seedling growth, however effect on ECM development, mainly ECM morphology was detected. Knowledge regarding to influence of environmental conditions, especially of substrate properties on development of ECM symbiosis of seedlings in forest nurseries were confirmed. Seedlings inoculated with Tricholoma achieved significantly better stem growth than those uninoculated. There were not found significant differences between the other growth characteristics. The results indicate that application of the test fungi moderately stimulated growth of above ground part of seedlings. Estimation of ectomycorrhizas, especially abundance of ECM morphological types in various treatments show, that indigenous symbiotic fungi were mainly responsible for ECM development, but the most probably artificially introduced fungi were also participated in ECM performance. Because the development of ectomycorrhizas depends on relationship among the fungi, their hosts, and environmental conditions, these results with the test isolates in given conditions do not guarantee that these fungi in different conditions will give equal results.