Copper Tolerance and Accumulation of Elsholtzia splendens Nakai in a Pot Environment

ABSTRACT

Elsholtzia splendens Naki has been identified as a copper (Cu) geobotanical indicator. In this study, the effects of Cu supply levels (control, 100, 200, 400, 600, 800, 1000, 1200 mg kg¹) on the growth and Cu accumulation in E. splendens were studied in one pot experiment. The results showed that no reduction in shoot height and dry weight was noted when the plants were grown at Cu supply levels up to 1000 mg kg⁻¹ in soil. Slight stimulation on shoot growth was noted at Cu levels ≥ 100 mg kg⁻¹. Copper concentration in shoots and roots increased with increasing Cu levels, and reached a maximum of 1751 and 9.45 mg kg⁻¹ (DW) at 1200 mg Cu kg⁻¹. The amount of Cu accumulated in the roots and shoots were 313 and 22 μ g plant⁻¹ at external Cu levels of 1000 and 800 mg kg⁻¹, respectively. The shoot/root Cu ratios ranged from 0.005 to 0.008 and more than 92% of the total Cu taken up by E. splendens was accumulated in roots. Furthermore, Cu concentrations in roots and shoots were significant and positively correlated with total soil Cu, water, ammonium nitrate (NH₄NO₃), ammonium (NH₄)-acetate, and ethylenediaminetetraacetic acid (EDTA) extractable Cu. These results indicate that E. splendens can considered as a Cu tolerant and accumulated plant, and root is the major part for accumulation of Cu in E. splendens.

Keywords:

• Elsholtzia splendens
• Copper (Cu)
• tolerance
• uptake
• accumulation
• polluted soil

Notes

*p < 0.05;

**p < 0.01.