Grafting as a mitigation strategy to reduce root-to-shoot cadmium translocation in plants of Solanaceae family

Cadmium (Cd) contamination in cropland poses a serious threat to food safety and human health. In this study we investigated the effects of grafting on Cd accumulation in the shoots of Solanum melongena (eggplant), Solanum lycopersicum (tomato) and Capsicum annuum L. (pepper) scion plants. The Cd mitigation effects were investigated in the un-grafted, self-grafted and grafted plants in both pot and field experiments. The results showed that grafting onto Solanum torvum rootstock can significantly decreased Cd accumulation in the shoots of eggplant, tomato and pepper scions by up to 85%. Moreover, our results demonstrated that the grafting operation did not significantly contribute to Cd accumulation in the scion plant shoots. However, using S. torvum as rootstock was significantly more effective in reducing Cd accumulation in tomato and pepper leaves as compared to using tomato cultivar Aimiao 2 or pepper cultivar Aimiao 1 as rootstocks. This suggests that the rootstock was responsible for lower Cd accumulation in the three scion plant shoots. Furthermore, there was a significant increase in yield and quality of plants grafted with S. torvum as rootstock. Overall, our finding suggests that grafting could be simultaneously used as a mitigation strategy to reduce Cd accumulation in the Solanaceae plant shoots and promote crop quality and yield. This study provides important insights for the safe use of low Cd-contaminated soils.