Conditioning of Scots pine (Pinus sylvestris L.) sowing material

ABSTRACT Scots pine is the main forest forming species in Poland. Despite the great importance of natural reconditioning of forest trees, a substantial source of reforestation is the nursery production of seedling material. Pre-sowing seed conditioning, consisting of chemical and physical treatments, is commonly used to improve seed quality as well as to advance uniform development and increase plant efficiency. The influence of semiconductor laser irradiation wavelength on Scots pine seeds (Pinus sylvestris L.) was tested in both laboratory and pot experiments. Irradiation rates used in trials were (D3) three-, (D6) six- and (D9) nine-fold of the basic rate of 2.5·10−1 J·cm−2 with a control (D0) of non-irradiated seeds. Irradiation accelerated emergence and increased seedling numbers. The germination energy and capacity of tested Scots pine genotypes were reduced under higher (D6) doses of laser irradiation. Stimulation of morphological traits and increase in chlorophyll contents was observed under the lowest (D3) irradiation rate, while an increase in polyphenol contents occurred under the highest, nine-fold rate of irradiation.