Altitude modulates growth and bioactive compounds in two Gastrodia elata forms through the microenvironment and soil microbes

Haixin DiaoDaichuan PanJunfei WangShunxing Guo^*

• Chinese Academy of Medical Sciences and Peking Union Medical College Institute of Medicinal Plant Development, Beijing, China

Gastrodia elata Bl., a medicinal-edible orchid with distinct vertical distribution, suffers from unstable yield and inconsistent quality in cultivation. However, how altitude shapes these traits in different forms remains unclear. We conducted field experiments on G. elata f. glauca and G. elata f. elata across three altitudes (650, 1653, 1953 m) in the Qinba Mountains utilizing a single consistent Armillaria strain, analyzing microclimate, soil properties, enzyme activities, culturable bacteria, and bioactive compounds. Key findings reveal form-specific altitudinal responses: total yield peaked at the high-altitude site (1953 m; 2668.11 ± 317.10 g), while bioactive compounds (gastrodin, parishins) were enriched at the middle-altitude site (1653 m)—with optimal accumulation at the Large Baima stage (f. glauca) and Mima stage (f. elata). For quality regulation, soil pH emerged as the primary correlative factor for f. glauca (explaining 52%-70.5% of variation in different RDAs), while integrated carbon-acquiring enzyme activity (16.6%) was key for f. elata—consistent with PLS-SEM evidence that f. elata quality was indirectly linked to soil properties via enzyme activities. Culturable tuber-associated bacteria—dominated by Pseudomonadota and least diverse at middle altitude)—exhibited divergent correlations with yield and quality: positive with yield but negative with quality in f. glauca; weakly positive with yield and strongly but non-significantly positive with quality in f. elata (p < 0.05). Our findings clarify form-specific correlative networks underlying G. elata yield and quality, providing targeted guidance for ecological cultivation.