Abstract: This study investigated the physiological and biochemical characteristics and adaptability of Rhododendron tomentosum in four forest types (Betula platyphylla forest, Larix gmelinii forest, the mixed coniferous broad leaved forest where the dominant species in the tree layer is B. platyphylla and L. gmelinii, and Pinus pumila forest), and conducted a fuzzy evaluation of each forest type to comprehensively investigate the physiological and ecological characteristics and adaptability of Rhododendron tomentosum under different forest types. The results showed that different forest types had significant effects on the photosynthetic physiological characteristics of R. tomentosum. In B. platyphylla forest, R. tomentosum showed strong photosynthetic ability, high photosynthetic pigment content, high antioxidant enzyme activity, relatively high total polyphenols and total flavonoids content, and strong photosynthetic growth and stress resistance, which indicated that R. tomentosum was better adapted to this forest type. In mixed coniferous broad forest and L. gmelini forest, R. tomentosum had high volatile oil content, and the rest of the indexes were in the moderate level, and the adaptability was moderate. However, in P. pumila forest, the photosynthetic capacity of R. tomentosum was weak, the antioxidant enzyme activity was low, and the stress tolerance was relatively weak, but its total polyphenols and total flavonoids and anthocyanins content was high to adapt to the high alpine environment, which showed a certain degree of adaptability to the environment. This study provides a theoretical basis for the in-depth understanding of the growth pattern and adaptive mechanism of R. tomentosum under different forest types, and also provides theoretical support and practical guidance for the ecological protection, resource utilization and forestry production of R. tomentosum.

Key words: Rhododendron tomentosum, forest type, physiological and biochemical properties, correlation analysis, adaptability