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 to analyze their adaptive strategies to light environments, this study used 5-year-old P. neoveitchii seedlings as the research objects, applied 6 different light transmittance treatments, measured physiological indices after 60 days, and conducted correlation and membership function analyses. 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 P. 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 P. neoveitchii to changes in light intensity. Membership function analysis revealed that the physiological indices of P. 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.