Physiological responses of Picea neoveitchii seedlings to different light intensities

To reveal the effects of different light intensities on the physiological characteristics of Picea neoveitchii seedlings and analyze their adaptive strategies to light environments, this study took 5-year-old Picea neoveitchii seedlings as the research object, set six different light transmittance treatments, and measured physiological indices after 60 days, followed by correlation analysis and membership function analysis. Under different light transmittance conditions, significant differences were observed in the contents of soluble sugar, soluble protein, Peroxide Enzyme (POD) activity, Catalase (CAT) activity, Superoxide Dismutase (SOD) activity, and chlorophyll a content in Picea neoveitchii seedlings. However, no significant differences were found in Pro Proline (Pro) content, Malondialdehyde (MDA) content, and Chlorophyll b (Chlb) content.Correlation analysis showed strong correlations among SOD activity, CAT activity, soluble sugar content, and POD activity, indicating that these physiological regulations are the main response strategies of Picea neoveitchii to changes in light intensity. Membership function analysis revealed that the physiological indices of Picea neoveitchii seedlings performed best at a light transmittance of approximately 63.74%. Therefore, in seedling cultivation and management, a light environment with a transmittance of about 60% is recommended. When returning seedlings to the wild, habitats with moderate canopy density such as forest edges or forest gaps are suitable choices.