Characteristics of Wood Substance Formation during Growing of Scots Pine Seedlings Using Chemical Markers

Currently, seedlings of the main silvicultural species are grown in greenhouses by the technology of ball-rooted planting material production. The process features raise the issue of the resulting planting material sustainability in relation to environmental conditions. Seedling growth and development in multi-rotation growing schemes will be influenced by both greenhouse and hardening site conditions. This makes assessing the planting material readiness for transfer to the open ground an urgent scientific task. Secondary metabolites (end products of biosynthesis) are one of the most suitable indicators for such an assessment from a chemical point of view. This study aims to explore chemical markers of wood substance formation as a criterion for completion of the annual development cycle of seedlings (at summer sowing dates) and their readiness for planting in the open ground. Scots pine is a good model object for the research, since it is a typical representative of coniferous forests, has an extensive range of growth as well as a high adaptive potential. Pine seedlings are usually highly sensitive to environmental conditions in the early stages of development. Physicochemical methods were used for the analysis of the biosynthesis processes of the main wood substance components. The seasonal dynamics of phenolic compounds content in different parts of annual Scots pine seedlings showed that the plants adapt to the temperature changes when they are brought to the hardening site. The adaptation includes a decrease in the content of low-molecular phenolic compounds preventing the development of uncontrolled oxidative processes when plant is exposed to adverse and stressful environmental conditions. It was found that the changes in the content of coniferyl alcohol as a precursor of lignin structures of coniferous wood can serve as a marker of lignification in the studied vegetation process. The content of phenolic compounds (at least 120–140 mg/g of TOC) and the peroxidase activity in needles (0.1–0.3 units of activity) may serve as criteriа for the completion of the annual cycle of seedling formation and the degree of its readiness for planting in the natural environment. For citation: Gusakova M.A., Bogolitsyn K.G., Krasikova A.A., Selivanova N.V., Khviyuzov S.S., Samsonova N.A. Characteristics of Wood Substance Formation during Growing of Scots Pine Seedlings Using Chemical Markers. Lesnoy Zhurnal [Russian Forestry Journal], 2022, no. 1, pp. 36–48. DOI: 10.37482/0536-1036-2022-1-36-48