Figure 2 .
Tolerance indices (%) based on relative root length of different populations of Rumex acetosa and Commelina communis under four Cu treatments in hydroculture (0.25, 40, 160, and 320 μmol L-1CuSO4, respectively; M: metallicolous; NM: non-metallicolous). Different letters on the error bars indicate a significant difference at P < 0.05 (LSD test) under the same treatment.
Ye et al. BMC Evolutionary Biology 2012 12:84 doi:10.1186/1471-2148-12-84