Competitive Inhibitory Effect of Calcium Polypeptides on Cd Enrichment of Brassia campestris L.

Abstract

Most cadmium-polluted farmland and land surrounding mining areas are difficult to repair and control, seriously threatening the food safety of the crops planted in these regions. As an essential element for plant growth, calcium plays an important role in stress-resistance regulation. In this study, Brassia campestris L. was used as the experimental material and polluted soil with cadmium was used as the experimental soil sample, to explore the competition inhibition of calcium polypeptide application on the absorption of Cd2+ by Brassia campestris L. in the growth process, as well as the effect of calcium application on the growth. Results showed that the application of calcium polypeptides significantly promoted the growth of Brassia campestris L. Calcium polypeptides could be used as high-quality fertilizer, alleviating the effect of Cd2+ stress on the growth of Brassia campestris L., and promoting the absorption of K+, Ca2+, and other nutrients by Brassia campestris L. Under different calcium polypeptide application conditions, the effective state of Cd2+ in the soil showed less significant difference, indicating that the calcium polypeptide had weak or limited passivation effects on Cd2+. There was a significantly negative correlation between Cd concentration in Brassia campestris L. and calcium application (r = −0.99, p < 0.01) when calcium polypeptide was over-applied, which indicates that the inhibition effect of Cd2+ absorption on Brassia campestris L. is mainly through competitive inhibition rather than passivation. The results showed that calcium polypeptide has dual functions on the competitive inhibition of heavy metals and a good fertilizer effect, providing a new technology for in situ remediation of heavy-metal pollution, and a new approach for the treatment of cadmium-contaminated farmland and surrounding mining land.

Agricultural Strategies to Reduce Cadmium Accumulation in Crops for Food Safety

“…Although a similar significant decrease in Cd accumulation in Boehmeria nivea was observed under 5 mM Ca treatment, a contrasting significant increase in Cd uptake and accumulation was unraveled under 1 mM Ca treatment [110], supporting the dose-dependent effect of Ca on Cd uptake in plants. The repression of Cd accumulation by Ca supplements was significant at 2-3 mM; suppression reached its peak when the Ca concentration was at 5 mM [47]. Similar reductions in Cd absorption and accumulation in the wheat and soybean roots were observed at Ca concentrations of 1 mM and 10 mM [111].…”

“…A decrease in the root Cd concentration of Brassica juncea was observed under a Ca + Cd combination rather than Cd alone [109]. The Ca polypeptide not only promoted the plant growth of the Brassica campestris but also showed competitive inhibition of Cd uptake in plants [47].…”

“…Competitive inhibition effect of calcium on Cd enrichment in plants. [47] Calcium dichloride (CaCl 2 ) 200. 4 200, 300 Brassica juncea Peat, Perlite and Sand (1:1:1, v/v/v) Decreased Cd content and Improved growth and biomass yield of Brassica plants.…”

Interactive Effects of Lanthanum and Calcium on Cadmium Accumulation in Wheat with Special Reference to TaNramp5 Expression Regulated by Calmodulin

“…38 Ca is an important macronutrient for plants and plays a significant regulatory role in the growth and development of plants and in the response to abiotic stress. 39 The positive effects of Ca on plant growth under Cd exposure have long been confirmed as a result of Cd−Ca antagonism. 40−42 This study also showed similar results that 10 mM Ca ameliorated the toxicity of Cd, whereas the toxicity was enhanced when supplemented with 0.5 mM Ca (Figure 1).…”