Reducing cadmium (Cd) accumulation in wheat is an effective way to decrease the potential threats of Cd to human health. The application of lanthanum (La) in agricultural fields is eliciting extensive attention due to its beneficial effects on improving yields and inhibiting Cd accumulation in edible parts of crops. However, the potential mechanism of La-restricted Cd accumulation in crop grains is not entirely understood. Here, we investigated the effects of La and Cd accumulation in wheat grains by implementing application at the shooting and heading stages. Some associated mechanisms were explored. Results showed that La application at the shooting and heading stages considerably promoted the thousand-grain weight. La application at the shooting and heading stages increased Cd accumulation in the first node beneath the panicle (N1) but reduced Cd levels in the other tissues. La application at the heading stage exerted greater effects on Cd storage in N1 while reducing Cd concentrations in the other tissues compared with La application at the shooting stage. La addition substantially decreased the translocation of Cd from the lower nodes to the upper internodes, but increased Cd translocation from the lower internodes to the upper nodes. The expression of TaZIP7 in N1 was downregulated by La treatment. These results suggest that the effective reduction in Cd in wheat grains by La application at the heading stage is probably a consequence of the successful promotion of Cd storage in nodes by downregulating the expression of TaZIP7 during the grain-filling stage, thereby hindering the redirection Cd from nodes to grains.

Calcium (Ca) and selenium (Se) are garnering growing interest because of their capacity to boost crop yields and minimize cadmium (Cd) concentration within edible parts. However, whether Ca and Se can synergistically inhibit Cd accumulation in crops and its mechanism remains poorly understood. A hydroponic experiment was conducted under Cd exposure with the combined supplementation of Ca and Se, specifically focused on Cd accumulation and its mechanism. The results revealed that Ca and Se synergistically enhanced growth and photosynthetic content, whereas they inhibited Cd accumulation in the roots, stems, and leaves of peppers. Ca and Se also synergistically reduced the content of Cd in the cell wall, organelle fraction, and soluble fraction of the roots, as well as in pectin, hemicellulose I, hemicellulose II, and cellulose. Ca and Se supplementation synergistically downregulated the expression levels of CaNramp1, CaNramp5, CaHMA1, and CaHMA2. These results revealed that Ca and Se synergistically reduced Cd accumulation in peppers by modulating targeted gene downregulation involved in Cd absorption and translocation.