| 摘要 |
[Objectives] To analyze the differences in medicinal component contents of Magnolia officinalis across different altitude gradients and explore their causes. [Methods] In this experiment, M. officinalis trees aged 15-20 years growing at four altitudes (1 301, 1 444, 1 573, and 1 643 m) were selected as experimental materials. Leaf traits, soil physicochemical properties, and medicinal component contents were investigated, and the relationships among leaf traits, soil physicochemical properties, and medicinal components were analyzed. [Results] With increasing altitude, the specific leaf area (SLA) of M. officinalis significantly increased, while stomatal density, vein density, leaf thickness, and mesophyll tissue thickness decreased. Soil total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), and organic matter contents (OM) decreased significantly with altitude, whereas available potassium (AK) showed the opposite trend. The contents of medicinal components magnolol and honokiol in M. officinalis also significantly decreased with altitude. Correlation analysis revealed that, in addition to altitude, soil physicochemical properties (pH, TP, OM) and leaf traits (leaf thickness, palisade tissue thickness, SLA) were significantly correlated with magnolol and honokiol contents. [Conclusions] M. officinalis at lower altitudes exhibited better growth and higher magnolol and honokiol contents, which may be attributed to higher soil nutrient availability in low-altitude regions. This study provides guidance for selecting cultivation sites and optimizing planting patterns for M. officinalis. |
