RESUMEN
<p><b>OBJECTIVE</b>To study the effect of phosphorus on copper tolerance in Achyranthes bidentata.</p><p><b>METHOD</b>A PVC pipe experiment was conducted to study the interactive effects of phosphorus (P) and copper (Cu), on growth, elemental accumulation and chemical constituents of A. bidentata. Two levels of elemental P were applied at 0 (P0) and 100 ( P100) mg x kg(-1) soil with 5 levels of Cu at 0 (Cu0), 100 (Cu100), 200 (Cu200), 200 (Cu400), 200 (Cu600) mg x kg(-1) soil, respectively.</p><p><b>RESULT AND CONCLUSION</b>The biomass production between different Cu treatments, phosphorus treatment showed significant differences. The biomass reached the maximum value as the concentration of Cu and P was 100 mg x kg(-1). Low concentration of Cu improved the growth of A. bidentata. The growth was blocked as Cu concentration reached 200 mg x kg(-1) in soil, however the contents of oleanolic acid and ecdysterone in roots of A. bidentata had not influenced by Cu. P could improved the copper tolerance in A. bidentata and increased root yield. The Cu concentration in soil of the cultivation bases must be below 200 mg x kg(-1) in order to produce good quality of medicinal material.</p>