Plants residing in metal-contaminated environments may develop tolerance to metal stress, and such tolerance could be passed on to their offspring. In this experiment, we aimed to test the hypotheses that elevated sediment Zn and Pb could induce tolerance to J. acutus inhabiting the metal contaminated estuaries (Hunter river, Lake Macquarie and Sydney Olympic Park), and such tolerance may be transferred to F1 offspring. Thus, J. acutus seeds (F1 generation) were collected from F0 parent plants dwelling at nine locations (a gradient of metal contaminated to uncontaminated) across NSW, Australia. Germination toxicity bioassays were established by exposing the seeds to increasing concentrations of Zn (0.0, 0.1, 0.2, 0.4, 0.8, and 1.6 mM) and Pb (0.0, 0.03, 0.06, 0.13, 0.25, and 0.50 mM) for 9 days in temperature-controlled growth cabinets. Zn EC50 (% germination) exhibited a significant positive linear relationship with both culm (R2 = 0.51, p = 0.03) and capsule (R2 = 0.57; p = 0.03) Zn concentrations, implying tolerance was acquired by offspring for this essential metal. J. acutus seeds, however, did not exhibit tolerance against the non-essential metal Pb. Tolerance to the essential metal Zn may be because Zn is very mobile in the plant, and seeds accumulate high Zn loads, i.e. a significant portion of sediment Zn reaches the culms (BCF = 0.58) and capsules (BCF = 0.84). In contrast, the non-essential metal Pb is mostly restricted in the plant's roots (BCF = 0.60) with little mobility to the shoots (culms and capsules BCF 0.01 and 0.05, respectively). Thus, Zn tolerance in J. acutus seeds is likely attributable to acclimatisation via maternal transfer of Zn; however, further manipulative experiments are required to disentangle potential acclimation, adaptation or epigenetic effects in explaining the tolerance observed.