Adaptation strategy of leaf functional traits inthe endangered plant Ormosia henryi to plant size andenvironmental gradients postprint

Abstract: To clarify how leaf functional traits of the endangered plant Ormosia henryi respond toenvironmental changes and ontogenetic processes, our study selected 105 individuals from24wild populations in Jiangxi Province. Four key traits—leaf thickness (LT), specific leaf area (SLA), leaf dry matter content (LDMC), and leaf tissue density (LTD)—were measured. Byintegrating data on tree diameter at breast height (DBH), climate, and soil properties, andemploying correlation analysis, principal component analysis, and linear mixed-effects models, our study systematically analyzed the primary drivers of leaf trait variation in O. henryi. The results were as follows: (1) The variation differs among leaf traits of O. henryi exhibitedsignificant variation. SLA was the most variable trait (CV = 30.87%), whereas LDMCwas the most conservative (CV = 8.03%). (2) Variation in LT, SLA, and LTD was primarily driven by plant size (DBH), whereas LDMC was most sensitive to climatic factors. (3) As plant size increased, the ecological strategy of O. henryi shifted from an "acquisitive" to a "conservative" strategy, characterized by a significant decrease in SLA and significant increases in LT, LDMC, and LTD; (4) Along climatic gradients, increased annual precipitation and precipitation seasonality, as well as increased mean annual temperature and reduced temperature seasonality, were associated witha more conservative trait syndrome in O. henryi. Our study demonstrates that leaf trait variation inO. henryi is co-regulated by plant ontogeny (size) and environmental factors, revealing its unique ecological adaptation strategy. Specifically, Ormosia henryi tends to adopt a more conservative resource-use strategy as individuals grow larger and under conditions of higher precipitation (andits seasonality) or warmer temperatures with reduced thermal seasonality. These findings provide a theoretical foundation for understanding the endangerment mechanisms of O. henryi and for developing targeted conservation measures