Fig. 7
Structural equation model assessing the impacts of soil properties, plant activities, and bacterial and fungal communities on alkaloid biosynthesis at two sites (H and L). The width of the arrows signifies the magnitude of significant standardized path coefficients (p < 0.05), with red arrows indicating positive correlations and blue arrows indicating negative correlations. Gray lines represent pathways with non-significant coefficients. Significance levels are indicated as follows: ***p < 0.001; **p < 0.01; *p < 0.05.
