PRE-SOWING SEED TREATMENT WITH PHYSICAL STRESSORS INDUCES CHANGES IN AMOUNT OF SECONDARY METABOLITES IN NEEDLES OF PICEA ABIES SEEDLINGS
Tree resistance to pathogens is related to the general viability of trees, their growth energy, and ability to synthesize and to mobilize secondary metabolites (SMs), usually phenolic compounds, in tissues. The total phenolic content (TPC) in Norway spruce needles was determined during two vegetation seasons in order to compare the chemical background and ability of different Norway spruce half-sib families to synthesize TPC in response to seed treatment with physical stressors: cold plasma for 1 and 2 min (CP1, CP2) and electromagnetic field for 2 min (EMF2). TPC in seedling needles significantly differed between affected and control groups, but differences were stronger exerted during the first year of vegetation. In the first vegetation season, the strongest positive effects on TPC synthesis were induced by EMF2 treatment in 463 and 577 half-sib families, by CP1 treatment − in 457 half-sib family and by CP2 treatment − in 541 half-sib family; in the second vegetation season strongest effects were detected in CP1 treated 457 half-sib family and in CP2 treated 548 and 477 half-sib families. The half-sib families of Picea abies with higher TPC induced by seed treatment with different physical stressors could be more resistant to pathogens and diseases. The variance component of family for TPC variated from 14±10 % till 17±11 %, and was significant. The interaction of genotype and environment on TPC was as high as 49 ± 20%.