Physiological responses, tolerance efficiency, and phytoextraction potential of Hylotelephium spectabile (Boreau) H. Ohba under Cd stress in hydroponic condition

Abstract

A sand hydroponic experiment with different concentrations of 0, 5, 10, 20, 40 mg L−1 Cd was used to study the growth and physiological response of Hylotelephium spectabile (Boreau) H. Ohba. and its phytoextraction potential for Cd. The results showed that total plant biomass under 5 mg L−1 Cd treatment was slightly affected. The content of malondialdehyde (MDA) in leaf exposed to Cd was higher, and the POD and CAT activity exhibited a positive response to the low level of Cd addition (5 mg·L−1). The photosynthesis pigments were slightly inhibited, and the ultrastructure of chloroplast remained intact after treatment with 10 mg L−1 Cd. The maximum leaf Cd content (603 mg·kg−1) was found in 5 mg L−1 Cd treatment, then decreased with the Cd level increased. The maximum Cd content in the shoots far exceeds the threshold level (100 mg kg−1) for a Cd-hyperaccumulator plant with the value of translocation factor (TFshoot/root) for Cd reaching up to 5.62. In conclusion, H. spectabile showed normal growth and physiological response and high shoot Cd accumulation under 5 mg L−1 Cd stress, which made it to be a good candidate for phytoextraction of low-level Cd polluted environment.