Fig. 9

The interaction relationship among yield, gastrodin content, plant subspecies, soil properties and climatic factors based on the PLS-PM model. (a) Direct effects of latent variables and manifest variables on yield; (b) Direct effects of latent variables and manifest variables on gastrodin content; (c) Indirect effects and total effects on yield; (d) Indirect effects and total effects on gastrodin content; The circles represent latent variables, and the rectangles represent manifest variables; The arrows represent the link between them, and the numbers next to the arrows indicate path coefficients; The solid red lines indicate negative effects, and the solid blue lines indicate positive effects; GAS represents gastrodin; PS represents plant subspecies; CF represents climatic factors; SPP represents soil physical properties; SCP represents soil chemical properties; SBP represents soil biological properties; Goodness of Fit statistics are shown in the frames; * represents P < 0.05, ** represents P < 0.01, and *** represents P < 0.001.