| Summary: | Euhalophytes, such as <i>Suaeda salsa</i>, are ideal candidates to remediate heavy metal-polluted saline soils. However, the metal tolerance ability of dimorphic seeds and subsequent seedlings is largely unknown. This study investigated the tolerance of <i>S. salsa</i> seeds to different concentrations of Cu<sup>2+</sup> (0–300 mM) and Zn<sup>2+</sup> (0–300 mM) during germination and seedling growth stages. Results showed that dimorphic seeds of <i>S. salsa</i> had high metal tolerance during germination, and even germinated under 300 mM Cu and Zn treatments. However, seedling growth was more sensitive to metal solutions and radicle growth was almost completely inhibited by Cu at 10 mM, and by Zn at 50 mM. Germinating seeds and seedlings of <i>S. salsa</i> had a higher metal toxicity threshold of Zn than that of Cu. In all indexes, indexes of radicle were the most sensitive and effective indicator of metal tolerance. Seeds of <i>S. salsa</i> germinated successfully and seedlings survived under high Zn and Cu stress. The results suggest that <i>S. salsa</i> could be sown directly in heavy metal-contaminated soils for phytoremediation.
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