Climate-Driven Variation in Habitat Suitability and Phytochemical Composition of Dendrobium officinale in China

Dendrobium Officinale is an endangered medicinal orchid with high therapeutic value. Understanding where it can grow well and where its medicinal compounds accumulate most is important for both conservation and cultivation. In this study, we used species distribution modeling (MaxEnt) to predict suitable habitats for D. officinale in China, and combined this with field sampling and UV-Vis spectrophotometry to analyze the content of bioactive compounds in plants from four producing areas in Guizhou Province. Our results show that the potential distribution of D. officinale is primarily constrained by moisture-related variables, especially precipitation of the driest quarter, annual precipitation, and vapor pressure, as well as vegetation activity (NDVI). The total suitable area was estimated at approximately 21.4 × 104 km2. Phytochemical analysis of samples from four sites in Guizhou Province suggested that the accumulation of polysaccharides, alkaloids, and total phenols may respond differently to environmental factors. Alkaloids and total phenols showed strong negative correlations with precipitation-related variables (bio12, bio17), while polysaccharides exhibited positive correlations with these same variables. However, these correlations are based on a small sample (n = 4) and should be interpreted as exploratory hypotheses specific to Guizhou, rather than as established relationships. They point to the possibility that water availability during the dry season may exert opposing effects on different classes of secondary metabolites, but this conjecture requires verification with expanded sampling. Overall, this study provides a spatial framework that can inform site selection for cultivation and conservation, rather than a fully validated precision agriculture tool.