Application of monochromatic blue light during germination and hypocotyl development improves outplanted Scots pine (Pinus sylvestris L.) trees performance

•Effect of monochromatic and white light studied in Scots pine seedlings.•Light treatment applied during germination and hypocotyl development at nursery.•Quantitative morphological attributes analyzed in outplanted trees.•Blue light significantly improved the quality of outplanted trees. Light quality has been recognized as an important factor to enhance plant production and quality, and it is extensively used in horticulture. Conifer seedlings are also known to respond to light quality, which can serve as a mean to improve seedling quality during its nursery production. We conducted a novel study regarding the effect of three monochromatic (blue, red and far-red) and white light treatments during germination and hypocotyl development in Scots pine seedlings which had an impact on the quantitative morphological attributes of shoot, root, fibre dimensions, survival and lignin content, after long-term transplantation in natural conditions. Our approach is a proxy to the effect of nursery light treatments on seedling performance following its post-planting establishment in the forest. Our study conducted during three growing seasons, reveals that monochromatic blue light applied at nursery significantly improved the outplanted Scots pine trees quality.