An effective planting model to decrease cadmium accumulation in rice grains and plants: Intercropping rice with wetland plants

Abstract

Cadmium (Cd) pollution affects plant growth and poses a serious threat to food safety and human health. Cadmium-contaminated rice is assumed to be the main source of Cd exposure to humans, with grave health risks. Phytoremediation is an efficient, cost-effective, and eco-friendly approach to minimizing Cd accumulation in rice. However, research on the effect of rice intercropping with wetland plants that exhibit great capacity for phytoremediation in decreasing Cd concentrations in paddies is limited. A pot experiment in glasshouse was conducted to evaluate the effects of rice intercropping with two wetland plants ( Pontederia cordata and Canna indica ) under different Cd levels (0, 1, 10, and 25 mg kg −1 ) on rice growth and Cd accumulation and translocation. The results showed that intercropping with the two wetland plants significantly improved the plant height, tiller, and biomass of rice but reduced the bioconcentration factors (BCFs) and Cd concentration in rice and wetland plants. Compared with rice monocropping, the BCF of rice grain in treatments with 25 mg kg −1 Cd was significantly decreased by 54.39% and 59.65% in rice intercropped with C . indica (RC) and rice intercropped with P. cordata (RP), respectively. In addition, intercropping inhibited the increase in BCFs in rice and wetland plants under increasing soil Cd content. In conclusion, the systems of rice intercropping with P. cordata and C . indica can be considered two new and effective approaches for ameliorating Cd pollution in paddies, as well as minimizing Cd accumulation in rice and improving food safety. Of the two intercropping systems, rice intercropping with P. cordata performed better than intercropping with C . indica.