Abstract: Efects of the environmental factors on the anthocyanin content in spathes and of improving flower quality with Ca²⁺ ,GA₃ treatments under weak light were investigated in Anthurium andraeanum．The resuits indicated that weak light was the main reason resulting in the lower anthocyanin content．Ca²⁺ (5.4 mmol· L^-1)，GA₃(1.16 mmol·L^-1)or Ca²⁺ +GA₃，respectively，significantly increased the anthocyanin content in spathes and the phenylalanine amonia lyase(PAL)activity in stem of Anthurium under weak light．It is found that the calmoduiin contents and PAL activity in vitro stem of Anthurium were inhibited th diferent inhibitors of calmoduiin，RNA and protein，and the probable mechanisms of Ca²⁺ ，GA₃were discussed．

Key words: Anthurium andraeanum, Ca²⁺, GA₃, Anthocyanin, PAL, Calmodulin, Inhibitor