A semi-thin section technique-based approach to quantify the xylem secondary cell wall deposition process

Identification of wood formation, cell wall deposition, lignification, and the maturation process contribute to a better understanding of biomass accumulation processes. Traditional methods for studying xylem development are limited by dyeing effects and discrimination experience, are non-quantitative for the degree of cell wall deposition and lignification, or are unsuitable for broad-leaved trees. In this study, we integrated several already existing methods to improve the discriminative accuracy of the cell development stage and to quantitatively describe the cell wall deposition and lignification degree for both softwood and hardwood tree species. To do this, we collected tree microcores every 7–14 days during a growing season for two species, one conifer (Platycladus orientalis) and one broad-leaved tree (Acer truncatum), in the mountainous areas in Beijing, China. We tracked the xylem development using semi-thin section technology combined with polarization microscopy. This integrated approach allows a quantitative description of the xylem cell wall deposition and lignification process of both hardwood and softwood tree species. This approach can be applied to demonstrate the dynamic process between the cambium layer and the production of wood cells and to describe the cell wall deposition and lignification process of wood cells from generation to maturation. This approach has certain application prospects for exploring scientific issues related to wood formation and accumulation processes in forestry and ecological studies.