Effect of different concentrations of Copper (Cu) on growth sttributes and bioaccumulation in Celesia argentea and Amaranthus hybridus

Cultivation of vegetables in polluted soil has been on the increase following the perceived fertility of such soil. This study investigated the growth performance and bioaccumulation of copper (Cu) in Amaranthus hybridus and Celosia argentea planted in Cu polluted soil. The research was conducted at the University of Ilorin botanical garden. Vegetable seedlings were transplanted into soil pots pre-treated with Cu - 100, 200 and 400 mg/kg; denoted as T₁, T₂ and T₃ respectively, and a control pot without Cu treatment. Amaranthus hybridus grown in soil polluted with 200 mg/kg of Cu gave the highest stem length at 1, 2 and 3 weeks after transplanting (WAT) i.e., 3.98, 5.00 and 7.05 cm respectively.  There was no significant difference in stem girth and leaf length and breadth of Celosia argentea grown in 200 mg/kg Cu (P<0.05). However, leaf length and breadth and number of leaves were significantly higher (P<0.05) in C. argentea grown in soil with same Cu concentration at 3 WAT i.e., 4.63 cm, 2.27 cm and 9.17 respectively. Bioaccumulation pattern recorded in A. hybridus indicated that those grown in soil polluted with 100 mg/kg of Cu have the highest elemental Cu accumulation (73.77 mg/kg). Amaranthus hybridus and Celosia argentea recorded highest wet and dry weights in those planted in soil polluted with 200 mg/kg of Cu.