Fig. 3
Soil chemical properties and their correlations with root gene expression. a Soil physical and chemical properties in rhizosphere soil samples from the core region differed from those in samples from the non-core region. Significance is indicated between core and non-core regions by the Wilcoxon rank sum test. AN, available nitrogen; TN, total nitrogen; ECsw, electrical conductivity of soil water. b Pairwise comparisons of environmental factors are shown, with a colour gradient denoting Spearman’s correlation coefficient. Root transcripts were related to each environmental factor by partial (geographic distance-corrected) Mantel tests. Edge width corresponds to Mantel’s R statistic for the corresponding distance correlations, and edge colour denotes the statistical significance based on 9999 permutations. Solid and dashed edges indicate positive and negative correlations, respectively