Foliar Spraying of Selenium Combined with Biochar Alleviates Cadmium Toxicity in Peanuts and Enriches Selenium in Peanut Grains

Abstract

Cadmium (Cd) pollution in soil, particularly in peanut production, is a problem that has attracted global concern and needs solutions urgently. Selenium (Se) can alleviate Cd toxicity; however, the underlying mechanisms are not completely understood. Therefore, two varieties of peanut (Arachis hypogaea Linn.), “Huayu 23” and “Huayu 20”, were chosen as the target crops for this study. A pot experiment was conducted to investigate the effects of two Se application methods combined with biochar on the accumulation of Cd and Se, and the best application method was identified. In addition, the role of Se in alleviating Cd toxicity in peanuts was studied. The results indicated that both Se and biochar decreased the Cd content in peanuts and alleviated Cd toxicity. However, the combined application of foliar Se and biochar significantly increased the peanut biomass by 73.44–132.41%, increased the grain yield of Huayu 23 by 0.60–1.09 fold, and Huayu 20 by 2.38–3.48 fold. Additionally, Cd content in peanut grains was decreased by 32.81–50.07%, and Se content was increased by 31.57–99.75 folds. Biochar can decrease the absorption of Cd from the soil, while Se can increase the accumulation of Cd in cell vacuoles by increasing glutathione and phytochelatin to decrease the movement of Cd into the grains. Therefore, our results indicate that the combined application of foliar Se and biochar can effectively promote the enrichment of Se in peanuts and suppress Cd toxicity.

Selenium-Containing Organic Fertilizer Application Affects Yield, Quality, and Distribution of Selenium in Wheat

“…By adding different concentrations of CdCl 2 and sodium selenite in the wheat hydroponic experiment, Se was found to limit the accumulation of Cd in wheat plants by regulating the subcellular distribution and chemical morphology of Cd in wheat tissues and the expression of TaNramp5-a, TaNramp5-b and TaHMA 2 in the roots [ 49 ]. Meanwhile, antagonism between Se and Cd has been found in other crops [ 50 , 51 , 52 ]. Therefore, the application of SOF in this study may have driven the wheat plants to directly inhibit the uptake of Cd at the wheat rhizosphere, thus effectively reducing the Cd content of the wheat grains.…”

Cadmium accumulation in peanut kernels: effect of location and genotype and its relationship with other factors

“…This suggested the importance of soil factors and the potential of appropriate agronomic practices in controlling Cd contamination in peanut. In a pot experiment, Shao et al (2022) demonstrated that foliar spray of selenium combined soil application of biochar signi cantly reduced Cd accumulation in peanut kernels. The effectiveness of similar agronomic measures under eld production conditions merits further attention.…”

Transcriptome Analysis Reveals the Mechanism of Exogenous Selenium in Alleviating Cadmium Stress in Purple Flowering Stalks (Brassica campestris var. purpuraria)

“…In China, hazardous metals have polluted around 2.0 × 10 7 hm 2 of arable land, and 2.8 × 10 5 hm 2 of farmland is contaminated with cadmium [4]. Due to its high toxicity, lengthy half-life, and difficulty in transformation and breakdown [5], the heavy metal element Cd poses a significant risk to soil-dwelling plant life, particularly crop growth. According to Zhang et al [6], the primary way that Cd enters the human body is through the consumption of agricultural byproducts.…”

“…Selenium has been shown to have a mitigating effect on Cd stress in a number of crops, including radish [33], rice [34][35][36], peanuts [5], wheat [37], maize [38], and oilseed rape [39,40]. However, relatively few studies have been done on purple flowering stalks as a plant, and it is still unclear how selenium influences the plant's defense mechanism against Cd stress at the molecular, biochemical, and physiological levels [41].…”