Expanding the information about the influence of cadmium on the metabolism of sunflowers: Evaluation of total, bioavailable, and bioaccessible content and metallobiomolecules in sunflower seeds

Abstract

The present study evaluates the effects of different doses of cadmium (0, 50, 350 and 700mg) on sunflower seeds, thus expanding the information available on this plant culture. For this task, the interaction between cadmium and key elements such as Cu, Fe, Mg, Mn, P, S and Zn is evaluated. An in vitro procedure is also performed to assess the cadmium bioavailability and bioaccessibility. Finally, metallobiomolecules are evaluated by SEC-ICP-MS in the seeds. The results indicated that cadmium is translocated to seeds such that the level of this element in the seeds was 130 times higher than the tolerable amount for the human body (0.1mgkg−1). An imbalance of other metals is also detected. While 92%, 72% and 74% of cadmium is bioaccessible in the control, Cd-low (50mg Cd) and Cd-high (700mg Cd) groups, respectively, its bioavailability was markedly different, with only 6.5%, 2% and 1% bioavailable from the same groups, respectively. This behavior reflects on the bioaccessibility and bioavailability of other elements also evaluated. In terms of metallobiomolecules, cadmium greatly interferes with Fe-biomolecules synthesis. Finally, cadmium interferes with the seed germination (2nd generation of seeds), by increasing the dormancy time (ca. 50% higher) and by decreasing the germination rate (ca. 60% lower) compared with the control group.