Phoebe sheareri is an excellent roadside tree with a wide distribution range and high ornamental value. Excessive moisture can affect the external morphology, the microstructure, and the ultrastructure of the leaf. Little is known at present regarding the leaf structure of P. sheareri under waterlogging stress. In this paper, the external morphology of leaves, the microstructure of leaf epidermis, and the ultrastructure of mesophyll cells of P. sheareri seedlings under waterlogging stress and drainage were dynamically observed. Waterlogging stress contributed to the yellowing and wilting of P. sheareri seedling leaves, the gradual closing of leaf epidermal stomata, increasing density of leaf stomata, gradual loosening of the arrangement of leaf cell structure, and merging of leaf palisade tissue cells. Waterlogging stress forced the structure of the chloroplast membranes to blur, gradually causing swelling, and deformation, with plasmolysis occurring in severe cases. During waterlogging, the basal lamellae were disorganized, and the mitochondrial membrane structure was damaged. The damaged state of the leaves was not relieved after drainage. Waterlogging stress not only inhibited the growth of leaves, but also accelerated the closure of stomata, disordered the arrangement of palisade tissue and spongy tissue gradually, and damaged the internal organelles of mesophyll cells.

The seeds of Tilia miqueliana Maxim. exhibit deep dormancy, which is categorized as combinational dormancy. This study utilized a comprehensive treatment involving magnetic fields, gibberellin (GA₃), and cold stratification to promote the release of seed physiological dormancy and enhance germination rates. After being soaked in 98% H₂SO₄ for 15 min, mature seeds of Tilia were exposed to magnetic field treatments (150 MT, 250 MT) for different durations (25 min, 45 min, 65 min, and 85 min), as well as GA₃ solution soaking (concentration: 0 μmol·L⁻¹, 1443 μmol·L⁻¹). Subsequently, cold stratification (0–5 °C) was applied to investigate the effects of these treatments on seed dormancy release and nutrient transformation. The results indicated that the comprehensive treatment involving magnetic field, GA₃ solution soaking, and cold stratification effectively released the physiological dormancy of Tilia seeds and improved germination rates. Among the treatments, M₁₅₀T₈₅G₁₄₄₃ (magnetic field intensity: 150 MT, magnetic field treatment time: 85 min, GA₃ soaking concentration: 1433 μmol·L⁻¹) exhibited the most favorable outcome. After 75 days of cold stratification following the comprehensive treatments, the germination rate of M₁₅₀T₈₅G₁₄₄₃ seeds reached 89%. Additionally, the levels of storage substances such as starches and crude fats within the seeds decreased, while the utilization of soluble sugars and soluble proteins increased. The M₁₅₀T₈₅G₁₄₄₃ treatment exhibited the highest degree of variation, leading to gradual increases in metabolic activities of the seeds and a transition from dormancy to germination.