Electric Field-Enhanced Cadmium Accumulation and Photosynthesis in a Woody Ornamental Hyperaccumulator—Lonicera japonica Thunb.

Abstract

The multi-system of electro-phytotechnology using a woody ornamental cadmium (Cd) hyperaccumulator (Lonicera japonica Thunb.) is a new departure for environmental remediation. The effects of four electric field conditions on Cd accumulation, growth, and photosynthesis of L. japonica under four Cd treatments were investigated. Under 25 and 50 mg L−1 Cd treatments, Cd accumulation in L. japonica was enhanced significantly compared to the control and reached 1110.79 mg kg−1 in root and 428.67 mg kg−1 in shoots influenced by the electric field, especially at 2 V cm−1, and with higher bioaccumulation coefficient (BC), translocation factor (TF), removal efficiency (RE), and the maximum Cd uptake, indicating that 2 V cm−1 voltage may be the most suitable electric field for consolidating Cd-hyperaccumulator ability. It is accompanied by increased root and shoots biomass and photosynthetic parameters through the electric field effect. These results show that a suitable electric field may improve the growth, hyperaccumulation, and photosynthetic ability of L.japonica. Meanwhile, low Cd supply (5 mg L−1) and medium voltage (2 V cm−1) improved plant growth and photosynthetic capacity, conducive to the practical application to a plant facing low concentration Cd contamination in the real environment.