关键词: 高寒植物, 光照强度, 土壤水分, 形态特征, 光合生理

Abstract: Aims Alpine wetlands play an important role in maintaining biodiversity and replenishing water sources. Exploring plant adaptability to the environment is the basis for effective prevention of wetland degradation and preservation of wetland ecosystem functions. However, it is unclear how soil moisture and light intensity, as two crucial factors for plant growth, interactively affect plant ecophysiology in alpine wetlands. Therefore, the present study explored the adaptation strategies of plants to changes in light intensities and soil moisture. Methods We applied a combination of two light intensities (ambient light and 60% of ambient light) and low, medium and high soil moisture (30, 55 and 85%, respectively) to the dominant species C. muliensis in the Zoige alpine wetland, and then determined growth, morphology, and photosynthetic fluorescence indicators. Important findings According to the leaf economics spectrum theory, specific leaf area (SLA) and photosynthetic rate can serve as two key strategy indicators for assessing plant adaptation to variations in light availability and soil moisture. Results revealed that: 1) Under ambient light conditions, the SLA and photosynthetic rate of C. muliensis increased with increasing soil moisture, reaching maximum values of 170.00cm²/g and 75.01μmolm^-2s^-1, respectively. The plant adaptation strategy changed from a conservative type to an acquisition type along the water gradient. 2) Shading alleviated drought stress to a certain extent. The maximum SLA and photosynthetic rate of C. muliensis under moderate water conditions were 234.98 cm²/g and 7.59 μmolm^-2s^-1, respectively. In this water condition, plants adopted the acquisition strategy, while it switched to be conservative with low SLA and low photosynthesis rate when soil humidity changed. 3) Compared to the ambient light, shade inhibited growth and reduced physiological activity of C. muliensis. In conclusion, the adaptive strategy of C. muliensis under different soil moisture conditions is closely linked to light intensity. It provides a theoretical basis for guiding the ecological restoration of degraded alpine wetlands under complex environmental conditions.

Key words: Psychrophyte, Light intensity, Soil moisture, Morphological characteristics, Photosynthetic physiology