Characterization of the Redox State of the Lignin-Carbohydrate Wood Matrix in the Initial Stages of Development Using the Example of Scots Pine

The studies of wood formation in the initial stages confirmed the deciding role of the redox transformations of monolignols in the lignification of the plant matrix. The change in the composition of the phenolic fraction (conjugated and non-conjugated phenolic structures) of the phenol-quinone redox system of the cell wall was examined using the derivative and differential UV spectroscopy. It was shown that the accumulation of low-molecular-weight phenolic compounds in the initial period of ontogenesis occurs mainly in the “needles” of the plants. It was confirmed that the seedlings being removed to the hardening site adapt to the existing temperature regime, which is associated with a decrease in the content of low-molecular-weight phenolic compounds preventing the development of oxidative processes. The plants are exposed to oxidative stress at low temperatures, when the enzymatic (peroxidase activity) system of plant protection is activated. The change in the coniferyl alcohol content as a marker of the lignification was shown. A correlation between the changes in peroxidase activity and the total content of phenolic compounds and the coniferyl alcohol content was demonstrated. The IR spectroscopic analysis showed a change in the carbohydrate to lignin component ratio in the initial stages of development of the Scots pine seedlings.