MOŽNOSTI HODNOCENÍ PODZIMNÍCH ZMĚN ODOLNOSTI K MRAZU U SADEBNÍHO MATERIÁLU RŮZNÝCH DŘEVIN.

From November 2018 until January 2019, the frost resistance of white oak (Quercus petraea (Matt.) Liebl.), European beech (Fagus sylvatica L.), Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) plantig stock was evaluated. After exposing the shoots to frost, the tissue damage was assessed by measuring: the ratio of electrical resistance before and after freezing (R1 /R2 ), the relative electrical conductivity of shoots leakage, and the occurrence of color changes in different tissues and chlorophyll fluorescence of the needles. The method of evaluating tissue color changes is reliable, but it takes long time to decide on the storability of plantig stock. From the faster methods, chlorophyll fluorescence measurement proved to be the most suitable for conifers. For the deciduous trees, it is suitable to measure the relative electrical conductivity of shoots leakage. [ABSTRACT FROM AUTHOR]