Fig. 4From: Metabolomics reveals arbuscular mycorrhizal fungi-mediated tolerance of walnut to soil droughtS-plot of orthogonal partial least squares discriminant analysis for metabolites between WW_AMF and WW_NAMF (a) and DS_AMF and DS_NAMF (b). Red dots and green dots indicate that these metabolites had a VIP value of < 1 and > 1, respectively. The abbreviations were shown in Fig. 1Back to article page