Hua Cheng

Cadmium (Cd) pollution in soil severely threatens the safe production of leafy vegetables and human health. Selenium (Se) can effectively restrict heavy metal uptake in crops. This study used water spinach (Ipomoea aquatica Forsk.) to investigate the effects of foliar-applied sodium selenite (Na₂SeO₃) and selenium nanoparticles (SeNPs) on plant growth, photosynthesis, antioxidant systems, Cd translocation, and rhizosphere microenvironment under Cd stress. Results showed that 2 mg/L Se exhibited the optimal mitigation effect. Compared with the Cd-only treatment, both Se forms significantly increased plant height by 80.00% and 72.38%, total chlorophyll by 40.39% and 38.97%, enhanced antioxidant enzyme activities and AsA-GSH levels, and reduced oxidative damage. Foliar Se also decreased shoot Cd content by 56.63% and 47.10%, translocation factor by 22.27% and 21.94%, while increasing Cd retention in cell walls. In the rhizosphere, Se reduced available Cd by 25.26% and 20.31% via converting acid-soluble Cd into stable fractions. Furthermore, Se reshaped rhizosphere metabolite profiles and recruited specific beneficial bacteria, improving soil enzyme activities and accelerating carbon and nitrogen cycling. In conclusion, foliar 2 mg/L Na₂SeO₃ or SeNPs synergistically alleviate Cd stress in water spinach by enhancing antioxidation, immobilizing Cd in cell walls, reducing Cd bioavailability, and optimizing rhizosphere microecology, providing a reliable technical basis for safe vegetable production in Cd-contaminated farmland.

Cadmium (Cd) contamination severely threatens the safe production of leafy vegetables and human dietary safety. Garland chrysanthemum displays strong Cd accumulation capability, leading to frequent Cd over-standard in edible tissues. In this study, pot trials combined with physiological biochemistry and multi-omics analysis were performed to systematically explore the physiological and molecular regulatory mechanisms of Na₂SeO₃ against Cd stress in garland chrysanthemum. Results demonstrated that soil application of 8 mg/kg Se markedly alleviated Cd-induced growth inhibition. Exogenous Se maintained chlorophyll biosynthesis and activated antioxidant defense system to eliminate excess reactive oxygen species and malondialdehyde. Meanwhile, Se promoted Cd immobilization in cell walls and vacuolar compartmentalization, elevated the proportion of low-toxicity Cd chemical forms, and reduced root-to-shoot Cd translocation efficiency, with root Cd concentration decreased by 11.50%–29.90%. Transcriptome and metabolome analyses revealed that Se modulated pivotal pathways including phenylpropanoid biosynthesis and plant hormone signal transduction, further activating functional gene modules associated with cell wall modification and antioxidant defense. Collectively, this study clarified a multi-dimensional synergistic mechanism of Se via root Cd retention, intracellular compartmental fixation and antioxidant protection, providing theoretical basis and technical support for safe cultivation of garland chrysanthemum in Cd-contaminated farmland.

Selenium (Se) is a beneficial trace element for the human body and also plays a crucial role in crop growth under stress conditions. This review systematically summarizes the regulatory effects, molecular mechanisms, and practical applications of Se in crop response to biotic and abiotic stresses. Specifically, Se alleviates stress damage through multiple pathways, including protecting the photosynthetic system, enhancing antioxidant defense capacity, regulating osmotic substance synthesis, maintaining intracellular ion balance, inducing defense-related substances, and promoting phenylpropanoid metabolism. At the molecular level, Se achieves stress regulation mainly by modulating the expression of stress-related genes (e.g., antioxidant, photosynthetic, and ion transport genes) and participating in key signal transduction pathways such as calcium signaling, mitogen-activated protein kinase (MAPK) cascade, and plant hormone signaling. In agricultural practice, different types of Se fertilizers (inorganic, organic, and nano-Se) are widely applied via soil or foliar application, and case studies on rice ( Oryza sativa L.) and wheat ( Triticum aestivum L. ) have confirmed their remarkable effects in improving crop stress resistance, yield, and quality. Despite significant progress, the core “Se-gene-stress” molecular regulatory network remains unclear, and precise Se-application technologies and long-term environmental impact monitoring still need optimization. Future research should focus on these deficiencies, integrate multi-omics and gene editing technologies to clarify the key regulatory mechanisms, optimize Se fertilizer application schemes, and explore Se’s synergistic effects with other elements, thereby providing strong theoretical support and practical guidance for sustainable agricultural development under stress conditions.

Cadmium (Cd) contamination severely threatens the safe production of leafy vegetables and human dietary safety. Garland chrysanthemum displays strong Cd accumulation capability, leading to frequent Cd over-standard in edible tissues. In this study, pot trials combined with physiological biochemistry and multi-omics analysis were performed to systematically explore the physiological and molecular regulatory mechanisms of Na₂SeO₃ against Cd stress in garland chrysanthemum. Results demonstrated that soil application of 8 mg/kg Se markedly alleviated Cd-induced growth inhibition. Exogenous Se maintained chlorophyll biosynthesis and activated antioxidant defense system to eliminate excess reactive oxygen species and malondialdehyde. Meanwhile, Se promoted Cd immobilization in cell walls and vacuolar compartmentalization, elevated the proportion of low-toxicity Cd chemical forms, and reduced root-to-shoot Cd translocation efficiency, with root Cd concentration decreased by 11.50%–29.90%. Transcriptome and metabolome analyses revealed that Se modulated pivotal pathways including phenylpropanoid biosynthesis and plant hormone signal transduction, further activating functional gene modules associated with cell wall modification and antioxidant defense. Collectively, this study clarified a multi-dimensional synergistic mechanism of Se via root Cd retention, intracellular compartmental fixation and antioxidant protection, providing theoretical basis and technical support for safe cultivation of garland chrysanthemum in Cd-contaminated farmland.

Cadmium (Cd) pollution in soil severely threatens the safe production of leafy vegetables and human health. Selenium (Se) can effectively restrict heavy metal uptake in crops. This study used water spinach (Ipomoea aquatica Forsk.) to investigate the effects of foliar-applied sodium selenite (Na₂SeO₃) and selenium nanoparticles (SeNPs) on plant growth, photosynthesis, antioxidant systems, Cd translocation, and rhizosphere microenvironment under Cd stress. Results showed that 2 mg/L Se presented the optimal mitigation effect. Compared with the Cd-only treatment, both Se forms significantly increased plant height by 80.00% and 72.38%, total chlorophyll by 40.39% and 38.97%, enhanced antioxidant enzyme activities and AsA-GSH levels, and reduced oxidative damage. Foliar Se also decreased shoot Cd content by 56.63% and 47.10%, translocation factor by 22.27% and 21.94%, while increasing Cd retention in cell walls. In the rhizosphere, Se reduced available Cd by 25.26% and 20.31% via converting acid-soluble Cd into stable fractions. Furthermore, Se reshaped rhizosphere metabolite profiles and recruited specific beneficial bacteria, improving soil enzyme activities and accelerating carbon and nitrogen cycling. In conclusion, foliar 2 mg/L Na₂SeO₃ or SeNPs synergistically alleviate Cd stress in water spinach by enhancing antioxidation, immobilizing Cd in cell walls, reducing Cd bioavailability, and optimizing rhizosphere microecology, providing a reliable technical basis for safe vegetable production in Cd-contaminated farmland.

Cadmium (Cd) pollution in soil severely threatens the safe production of leafy vegetables and human health. Selenium (Se) can effectively restrict heavy metal uptake in crops. This study used water spinach (Ipomoea aquatica Forsk.) to investigate the effects of foliar-applied sodium selenite (Na₂SeO₃) and selenium nanoparticles (SeNPs) on plant growth, photosynthesis, antioxidant systems, Cd translocation, and rhizosphere microenvironment under Cd stress. Results showed that 2 mg/L Se presented the optimal mitigation effect. Compared with the Cd-only treatment, both Se forms significantly increased plant height by 80.00% and 72.38%, total chlorophyll by 40.39% and 38.97%, enhanced antioxidant enzyme activities and AsA-GSH levels, and reduced oxidative damage. Foliar Se also decreased shoot Cd content by 56.63% and 47.10%, translocation factor by 22.27% and 21.94%, while increasing Cd retention in cell walls. In the rhizosphere, Se reduced available Cd by 25.26% and 20.31% via converting acid-soluble Cd into stable fractions. Furthermore, Se reshaped rhizosphere metabolite profiles and recruited specific beneficial bacteria, improving soil enzyme activities and accelerating carbon and nitrogen cycling. In conclusion, foliar 2 mg/L Na₂SeO₃ or SeNPs synergistically alleviate Cd stress in water spinach by enhancing antioxidation, immobilizing Cd in cell walls, reducing Cd bioavailability, and optimizing rhizosphere microecology, providing a reliable technical basis for safe vegetable production in Cd-contaminated farmland.

Traditional plastic preservation films face significant environmental challenges due to their non-degradable nature and limited functional versatility. In contrast, hydrocolloid–nanomaterial composite films—which integrate biopolymer matrices (e.g., cellulose, chitosan, alginate and gelatin) with nanoparticles such as SiO₂, Se, TiO₂, or ZnO—have emerged as a prominent research focus. These composite films preserve the inherent biodegradability and biocompatibility of hydrocolloids, while the nanomaterials, when stably dispersed, enhance interfacial interactions through electrostatic forces, hydrogen-bonding, or coordination bonds. This synergy endows the films with multifunctional properties, including antimicrobial activity, antioxidant capacity, UV-shielding performance, and stimuli-responsive intelligence. Prepared via techniques like electrospinning, solution casting, reactive extrusion, and coating, they exhibit excellent mechanical strength, barrier properties, and multifunctionality, effectively extending the shelf life of fruits, vegetables, meats, etc. However, challenges remain: nanomaterial dispersion, migration risks, and scalable production. This review summarizes recent advances to guide green preparation optimization, balance performance and safety, and advance sustainable development in food packaging.

Soil heavy metal (HM) pollution poses a severe threat to ecological security and human health. Selenium (Se) is an essential trace element for the human body and can regulate crop growth and development as well as HM uptake in HM-contaminated soils. The regulatory mechanisms of Se on HMs are mainly reflected in four aspects: Geochemical immobilization promotes the formation of metal selenide precipitates and the adsorption of HMs by soil colloids by regulating the rhizosphere redox potential (Eh) and pH value. Rhizosphere microbial remodeling drives the enrichment of functional microorganisms such as Se redox bacteria, plant growth-promoting rhizobacteria (PGPR), and arbuscular mycorrhizal fungi (AMF) through the dual selective pressure of Se toxicity and root exudates, in order to synergistically realize Se speciation transformation and HM adsorption/chelation. Root barrier reinforcement constructs physical and chemical dual defense barriers by inducing the formation of iron plaques on the root surface, remodeling root morphology and strengthening cell wall components such as lignin and polysaccharides. Intracellular transport regulation down-regulates the genes encoding HM uptake transporters, up-regulates the genes encoding HM efflux proteins, and promotes the synthesis of phytochelatins (PCs) to form HM complexes and lastly realizes vacuolar sequestration. Finally, we summarize current research gaps in the interaction mechanisms of different Se species, precise application strategies, and long-term environmental risk assessment, providing a theoretical basis and technical outlook for the green remediation of HM-contaminated farmlands and Se biofortification of crops.