Mechanisms of Cadmium Tolerance and Detoxification in Two Ornamental Plants

Cadmium (Cd) is an important environmental heavy metal and one of the main soil pollutants in southwest China and even the Yangtze River Basin because of its toxicity to plants and humans. To clarify the potential of Euryops pectinatus L. and Gardenia jasminoides J. and the mechanism they use to remediate Cd-contaminated soil, a soil pot experiment with 0, 5, 10, 20, and 40 mg kg−1 of Cd was used to investigate the accumulation characteristics, subcellular distribution, chemical forms, and the antioxidative defense systems of the two ornamental plants. When the concentration of Cd was below 40 mg kg−1, it promoted the growth of E. pectinatus shoots, and the tolerance index (TI) was >1. However, 20–40 mg kg−1 Cd significantly inhibited the growth of G. jasminoides, and the TI was