Figure 6. Relationships of root mass fraction (RMF) with maximum root depth (MRD), Root diameter (RD), Specific root length (SRL), specific root area (SRA), Root tissue density (RTD) and Topological index(TI).* indicates P <0.05, ** indicates P <0.01, and *** indicates P <0.001. Standardised major axis (SMA) regressions were fitted to the data.