Role of Soil and Foliar‐Applied Carbon Dots in Plant Iron Biofortification and Cadmium Mitigation by Triggering Opposite Iron Signaling in Roots

Abstract

In China, iron (Fe) availability is low in most soils but cadmium (Cd) generally exceeds regulatory soil pollution limits. Thus, biofortification of Fe along with mitigation of Cd in edible plant parts is important for human nutrition and health. Carbon dots (CDs) are considered as potential nanomaterials for agricultural applications. Here, Salvia miltiorrhiza‐derived CDs are an efficient modulator of Fe, manganese (Mn), zinc (Zn), and Cd accumulation in plants. CDs irrigation (1 mg mL−1, performed every week starting at the jointing stage for 12 weeks) increased Fe content by 18% but mitigated Cd accumulation by 20% in wheat grains. This finding was associated with the Fe3+‐mobilizing properties of CDs from the soil and root cell wall, as well as endocytosis‐dependent internalization in roots. The resulting excess Fe signaling mitigated Cd uptake via inhibiting TaNRAMP5 expression. Foliar spraying of CDs enhanced Fe (44%), Mn (30%), and Zn (19%) content with an unchanged Cd accumulation in wheat grains. This result is attributed to CDs‐enhanced light signaling, which triggered shoot‐to‐root Fe deficiency response. This study not only reveals the molecular mechanism underlying CDs modulation of Fe signaling in plants but also provides useful strategies for concurrent Fe biofortification and Cd mitigation in plant‐based foods.

Selenium Nanoparticles Mitigate Cadmium Stress in Tomato through Enhanced Accumulation and Transport of Sulfate/Selenite and Polyamines

“…In the soil experiment, 2-week-old tomato seedlings were cultured in 36-well hole trays containing a nursery substrate and then transferred to nutrient soil without Cd contamination (organic matter, 35.06 g kg –1 ; total Fe content, 805.36 mg kg –1 ; total Cd content, 0.05 mg kg –1 ; pH, 6.54) and cultivated under the same growth conditions as described above for the hydroponic experiment. Cd was then applied at a concentration of 0.65 mg kg –1 in the form of CdCl 2 . Shoot and root samples were collected for analysis at the corresponding time points.…”

Nanotechnology in Agriculture: Manganese Ferrite Nanoparticles as a Micronutrient Fertilizer for Wheat

“…Compared with soil treatment, spraying nano-scale Mn could provide superior control over plant responses and enhance grain yield [24]. Foliar applications of carbon dots resulted in a greater increase in nutrient elements such as Fe and Mn in wheat grains compared to soil irrigation [25]. The foliar spray application of CeO 2 NPs was more beneficial for Phaseolus vulgaris L. growth compared to soil application, as evidenced by proteomics and metabolomics [26].…”