Grafting and exogenous selenium (Se) application both regulate plant sulfur metabolism to reduce cadmium (Cd) accumulation. Numerous studies have investigated how each strategy individually mitigates Cd buildup in crops, but the effects of their combined use on crop Cd levels remain unexplored. Our research aims to clarify how grafting and agronomic Se biofortification reduce Cd translocation and accumulation in crops, providing a theoretical basis and methodological support for developing crop heavy metal blocking technologies and utilizing Cd-contaminated farmland. Solanum melongena and S. lycopersicum were used as scions, and S. torvum (wild eggplant) as the rootstock. The effects of grafting and exogenous Se experiments on Se and Cd contents, plant biomass, fruit quality, and element absorption were measured and comparatively analyzed. After the individual treatments, the Cd content in eggplant and tomato fruits decreased by 19-73% and 44-76%, respectively. The combined treatment reduced the Cd content in fruits by 77-94% and 79-95%, with Se more effectively reducing Cd when applied to soil than to leaves. Under individual grafting or Se application treatments, reduced Cd levels in eggplant fruits correlate closely with sulfur content, showing a significant positive correlation. In contrast, tomato fruits exhibit the opposite trend-likely due to variations in Se application rates and scion-rootstock interactions. For the combined treatment, lower Cd concentrations in eggplant fruits are strongly associated with Se levels, displaying a significant negative correlation. This pattern may arise because Se utilizes sulfur metabolic pathways to synthesize Se-containing compounds; Cd then reacts with these compounds and becomes sequestered in roots, stems, and leaves, reducing its translocation to fruits. Additionally, the combined treatment increased fruit yield by 22-25% in eggplants and 46-48% in tomatoes, while enhancing the contents of soluble sugars, soluble proteins, and vitamin C. The combined application of grafting and soil Se fertilization enabled the safe and effective production of Se-enriched vegetables with low Cd contents.

Organisms inherently preserve ancestral information within their bodies, proving evidence of evolutionary processes. Selenium, the least abundant essential element in the Earth's crust, has emerged as a limiting factor in the development of animal reproductive systems. By integrating selenium concentration information from plants and animals, this study demonstrates that the decline in Earth's surface selenium abundance may be associated with the origin and extinction of vertebrate species. Coal-derived selenium abundance data indicate that surface selenium may have been continuously lost, with depletion rates consistent with a natural decay process that could contribute to periodic vertebrate extinctions. The conserved selenium levels in animal germ cells imply that animals require selenium more strictly than plants, potentially imposing certain boundary conditions and constraints on the evolution of vertebrate reproductive systems (origin of new species). The syntheses here suggest that the biogeochemistry of selenium, broadly defined, provides new information and insight into the coevolution of vertebrate species and environment.

Grafting is an effective horticultural method to reduce Cd accumulation in crops. However, the mechanism of grafting inducing the decrease in Cd content in scions remains unclear. This study evaluated the effect of grafting on fruit quality, yield, and Cd content of Solanum melongena, and explored the potential mechanism of grafting reducing Cd content in scions. In the low Cd-contaminated soil, compared with un-grafted (UG) and self-grafted plants (SG), the fruit yield of inter-grafted plants (EG) increased by 38 %, and the fruit quality was not markedly affected. In EG, the decrease in total S and Cd content was not related to organic acids and thiol compounds. The decrease in total S and Cd content in EG leaves and fruits was closely related to the synthesis and transportation of glucosinolates (GSL). The genes encoding GSL synthesis in leaves, such as basic helix-loop-helix, myelocytomatosis proteins, acetyl-CoA, cytochrome P450, and glutathione S-transferases, were significantly downregulated. In EG leaves, the contents of five of the eight amino acids involved in GSL synthesis decreased significantly (P < 0.05). Notably, total GSL in EG stems, leaves, and fruits had a significant linear correlation with total S and Cd. In summary, the decrease in total S and Cd content in scions caused by grafting is closely related to GSL. Our findings provide a theoretical basis for the safe use of Cd-contaminated soil, exploring the long-distance transport of Cd in plants and cultivating crops with low Cd accumulation.

Microbial remediation technology has become one of the main remediation methods of polycyclic aromatic hydrocarbons（PAHs） contaminated soil due to its characteristics of reasonable price and environmental friendliness. However, it needs to be further improved because microbial remediation in soil that experience long-term aging is less efficient. Taking Pseudomonas aeruginosa（PAE）,the PAHs degrading bacteria, as the research object, this study systematically investigated the effects of graphene oxide（GO）,a new carbon nanomaterial, on the growth of PAE and the degradation of PAHs, as well as the effectiveness and mechanism of GO-enhanced PAE degradation of soil PAHs. The results showed that:（1） 50-100 mg/L GO could significantly promote the growth of PAE and the secretion of extracellular polymers（EPS）;（2） the degradation of PAHs in aged soil noticeably increased due to the addition of PAE and GO（100 mg/kg）;（3） in the early stage of GO addition, the abundance of PAE increased manifestly while the indigenous microbial communities decreased. After treatment, the abundance of soil bacterial community returned to the level of control group. The outcome revealed that the appropriate concentration of GO could not only affect the diversity and abundance of soil microorganisms, but also facilitate the decomposition of PAHs. However, these affections decreased at the later stage of restoration, thus the soil microbial community showed a “perturbation-recovery” pattern. This study is helpful to understand the role of GO on environmental microorganisms and has provided a deeper insight for enhanced microbial remediation of PAHs contaminated soil.

Graphene oxide (GO)-mediated phytoremediation is a novel strategy for abating polycyclic aromatic hydrocarbons (PAHs) from contaminated soils, but the underlying mechanism has not been fully investigated. In this study, Fire Phoenix plants were grown in soils contaminated by 105.00 mg kg-1 or 154.55 mg kg-1 PAHs, containing 15 mg kg -1 Cd and 0.0, 0.3, 0.4, or 0.5 g kg -1 GO, respectively. After 150 days of plant growth, PAH removal rates from low-PAHs/Cd and high-PAHs/Cd soils amended with 0.4 g kg -1 GO were 78.95% and 73.21%, respectively. GO particularly promoted the biodegradation of high-ring PAHs as the removal rate increased by 55.69% on day 120 of plant growth. Dioxygenase genes including nidA and pdoA2 directly degraded PAHs in GO-induced remediation. GO mediated both upstream and downstream degradation pathways of PAHs, during which the tricarboxylic acid cycle initially dominated the downstream pathway followed by carbohydrate and amino acid metabolisms. Soil Cd was also significantly reduced by GO-enhanced root absorption. This study for the first time elucidated the mechanisms underpinning the interaction of Fire Phoenix plants with microorganisms in remediation of soil PAHs and Cd and illustrated the viability of GO-mediated bioremediation of PAHs and Cd from co-contaminated soils.

Graphene oxide (GO)-promoted microbial degradation technology is considered an important strategy to eliminate polycyclic aromatic hydrocarbons (PAHs) in the environment; however, the mechanism by which GO affects microbial degradation of PAHs has not been fully studied. Thus, this study aimed to analyze the effect of GO-microbial interaction on PAHs degradation at the microbial community structure, community gene expression, and metabolic levels using multi-omics combined technology. We treated PAHs-contaminated soil samples with different concentrations of GO and analyzed the soil samples for microbial diversity after 14 and 28 days. After a short exposure, GO reduced the diversity of soil microbial community but increased potential degrading microbial abundance, promoting PAHs biodegradation. This promotion effect was further influenced by the GO concentration. In a short period of time, GO upregulated the expression of genes involved in microbial movement (flagellar assembly), bacterial chemotaxis, two-component system, and phosphotransferase system in the soil microbial community and increased the probability of microbial contact with PAHs. Biosynthesis of amino acids and carbon metabolism of microorganisms were accelerated, thereby increasing the degradation of PAHs. With the extension of time, the degradation of PAHs stagnated, which may be due to the weakened stimulation of GO on microorganisms. The results showed that screening specific degrading microorganisms, increasing the contact area between microorganisms and PAHs, and prolonging the stimulation of GO on microorganisms were important means to improve the biodegradation efficiency of PAHs in soil. This study elucidates how GO affects microbial PAHs degradation and provides important insights for the application of GO-assisted microbial degradation technology.

Cadmium (Cd) pollution in farmland soil increases the probability of wastage of land resources and compromised food safety. Grafting can change the absorption rates of elements in crops; however, there are few studies on grafting in bulk grain and cash crops. In this study, Glycine max was used as a scion and Luffa aegyptiaca as a rootstock for grafting experiments. The changes in total sulfur and Cd content in the leaves and grains of grafted species were determined for three consecutive generations, and the gene expression and DNA methylation status of the leaves were analyzed. The results show that grafting significantly reduced the total sulfur and Cd content in soybean leaves and grains; the Cd content in soybean leaves and grains decreased by >50 %. The plant's primary sulfur metabolism pathway was not significantly affected. Glucosinolates and DNA methylation may play important roles in reducing total sulfur and Cd accumulation. Notably, low sulfur and low Cd traits can be maintained over two generations. Our study establishes that grafting can reduce the total sulfur and Cd content in soybean, and these traits can be inherited. In summary, grafting technology can be used to prevent soybean from accumulating Cd in farmland soil. This provides a theoretical basis for grafting to cultivate crops with low Cd accumulation.

Grafting can effectively reduce cadmium (Cd) accumulation in Solanaceae fruits. However, few studies have investigated the mechanisms and stability involved, making it difficult to apply grafting to a large area of Cd-contaminated farmland. Soybeans were grafted with low Cd accumulation variety rootstocks and varieties with high Cd accumulation as scions. High-throughput sequencing and q-PCR were used to explore the mechanism and stability of rootstock-induced low Cd accumulation in scions. Grafting using low Cd accumulated varieties as rootstocks reduced the Cd content in the grafted soybeans by 50–70

Exotic plants could play an essential role in the restoration of heavy metal-contaminated soil. This study evaluated the tolerance of and extraction of cadmium (Cd) by ZCR (CR female x LT male), hybrids of Xanthium strumarium (LT, exotic species) and X. sibiricum (CR, indigenous congener), and their parental species under different Cd treatments (0, 10, 40, and 80 mg center dot kg(-1)). The results showed that the hybrids had significantly improved tolerance to Cd. Under Cd stress, the biomass of ZCR increased by more than 50% on average compared with that of CR. Moreover, the hybrids showed a more remarkable ability to transport Cd from the root to the shoot. The Cd content of the shoots of ZCR increased by 128.33, 147.22, and 252.63% when treated with 10, 40, and 80 mg center dot kg(-1) Cd, respectively. ZCR stored more than 70% of Cd in litter leaves, thereby reducing the toxic effects of Cd on photosynthesis and growth. The results showed that ZCR showed excellent Cd tolerance and enrichment in the presence of Cd. The hybrids of Xanthium strumarium and its native congener X. sibiricum may remediate soil Cd pollution. Novelty statement With the changing world economy and increasing human activities, exotic plants have become a global issue of common concern to the international community. This study describes new findings on using hybrids of the exotic plant of Xanthium strumarium and its native congener Xanthium sibiricum for the restoration of cadmium-contaminated soils. Under Cd stress, the hybrids' biomass, tolerance, and ability to accumulate Cd were significantly higher than that of X. sibiricum, indicating that hybrids gained useful heavy metal extraction traits from X. strumarium.

硒是人和动物必需的生命微量元素,其因具有防癌抗癌、防治心血管疾病、增强机体免疫力等生物学功能而越来越受到人们关注.近年来,富硒农产品的开发得到了迅速发展,如何在鸡养殖业中开展安全、稳定、高效的补硒技术已经成为行业的重点及热点.本文综述了硒的生物学功能、硒的代谢与毒性分析、不同硒源及其水平对鸡体生化影响的指标体系构建,并进一步展望了富硒饲料的开发利用前景.

Invasive plants could play an important role in the restoration of tailings, but their invasiveness limits their practical application. In this study, the phytoremediation potentials and invasive risks of an exotic invasive plant (Xanthium strumarium, LT), a native plant (X. sibiricum, CR), and combinations of inoculations (EG, with CR as the scion and LT as the rootstock; SG, with CR as both the scion and rootstock) were evaluated on Cd/Cu/Ni tailings. LT rootstock has a stronger nutrient and metal transport capacity, compared with CR. EG not only had higher biomass and Cd/Cu/Ni accumulation, but also abundant rhizosphere microbial communities. Hydroponic and common garden experiments showed that the growth and metal enrichment characteristics of EG are not inherited by plant offspring, which reduces the risk of the biological diffusion in the process of using exotic species. Transcriptome analysis shows that a large number of differentially-expressed genes in EG leaves and roots are involved in phenylpropanoid biosynthesis, secondary metabolite generation, and signal transduction. The genes induced in EG leaves, including cyclic nucleotide-gated ion channel, calcium-binding protein, and WRKY transcription factor, were found to be differentially expressed compared to CR. The genes induced in EG roots, included phenylalanine ammonia-lyase, cinnamoyl-CoA reductase, caffeoyl-CoA O-methyltransferase, and beta-glucosidase. We speculate that lignin and glucosinolates play an important role in the metal accumulation and transportation of EG. The results demonstrate that grafting with LT not only improved CR tolerance and accumulation of Cd, Cu, and Ni, but also created a beneficial microbial environment for plants in tailings. More importantly, grafting with LT did not enhance the invasiveness of CR. Our results provide an example of the safe use of invasive plants in the restoration of Cd/Cu/Ni tailings.

Large areas of soils, in the magnesite mining areas of northern China, are covered with a hard-white crust, which affects ecological functions of soil seriously, particularly reduce water penetration rate. To clarify the mechanism of crust preventing water from penetrating into soil, the process and thermodynamic mechanism of crust formation were studied through laboratory simulation experiments. The crust was mainly composed of magnesium oxide (MgO), magnesium carbonate (MgCO3), and magnesium dihydroxide (Mg(OH)2). MgCO3 and Mg(OH)2 were produced in the initial stage of crust formation. The increasing amount of MgCO3 and Mg(OH)2 enhanced the production of 4MgCO3·Mg(OH)2·4H2O. Mg(OH)2·MgSO4·8H2O was formed in the fourth week, which had a greater mechanical strength and became the framework of forming crust. In the latter stages, the increasing amount of 4MgCO3·Mg(OH)2·4H2O and MgSO4·6H2O made the crust to be tighter and harder. The crust formation was a sedimentary process, in which the deposition of dust was accompanied by complex chemical reactions. In addition, the thermodynamic parameters for main chemical reactions indicated that the crust formation was a spontaneous dynamic process. Therefore, the result of this study illustrated the changes of crust formation in different stages from different aspects. The findings of this study provide important information for understanding the formation of crust and developing effective approaches for soil remediation in affected areas.

镧系元素(稀土)应用的不断拓展引起了人们对其生物安全性的关注.为探明环境因素对镧系元素生物毒性效应的影响,以斑马鱼(Danio rerio)为受试生物,研究水环境因子(pH、HCO3-、Ca2+-Mg2+、K+和Cl-等)对镧系元素生物毒性和生物蓄积性的影响,分析不同水环境条件下4种代表性镧系元素(La、Ce、Gd和Ho)的毒性大小及其趋势.结果表明:在标准水中,La对斑马鱼成鱼的96 h-LC50为165.6 μmol·L-1,毒性大小与水中pH、HCO3-和Ca2+-Mg2+浓度显著相关,其斜率分别为0.912、1.135和0.222,而与水中Cl-、Na+、K+和S042-的浓度无显著性关系;4种镧系元素均可在测试开始阶段与HCO3-络合形成沉淀颗粒,pH的降低或HCO3-的减少可促进颗粒态镧系元素向可溶态转化,从而增强其生物毒性和生物蓄积性;在pH 5.0和HCO3-0.2 mmol·L-1(排除沉淀影响)条件下,4种镧系元素呈现毒性一致的趋势(对斑马鱼的96 h-LC50为6.11～6.43 μmol·L-1);可见,在标准水中,4种镧系元素毒性的差异可能是由于单个元素的有效态差异而不是元素的不同毒性所致.因此,在生物毒性机制的差异被揭露之前,镧系元素可视为一组具有毒性相加模式的元素进行生物毒性评估,评估过程应注重pH和碳酸盐的影响.

The continuous expansion of the application of rare earth elements (REEs) in various fields has attracted attention to their biosafety. At present, the molecular mechanisms underlying the biological effects of REEs are unclear. In this study, the effects of lanthanum (La) and gadolinium (Gd) on cell cycle progression in the root tips of rice seedlings were investigated. Low concentrations of REEs (0.1 mg L-1) induced an increase in the number of cells in the prophase and metaphase, while high concentrations of REEs (10 mg L-1) induced an increase in the number of cells in the late and terminal stages of the cell cycle, and apoptosis or necrosis. Additionally, low concentrations of REEs induced a significant increase in the expression of the cell cycle factors WEE1, CDKA;1, and CYCB1;1, and promoted the G2/M phase and accelerated root tip growth. However, at high REEs concentrations, the DNA damage response sensitized by BRCA1, MRE11, and TP53 could that prevent root tip growth by inhibiting the transcription factor E2F, resulting in obvious G1/S phase transition block and delayed G2/M phase conversion. Furthermore, by comparing the biological effect mechanisms of La and Gd, we found that these two REEs share regulatory actions on the cell cycle of root tips in rice seedlings.

Information on the effects of pollutants in sediments at an ecosystem level to validate current and proposed risk-assessment procedures is scarce. The most frequent criticism of these procedures is that responses of surrogate species in the laboratory are not representative of responses of natural populations. A tiered approach using both laboratory and microcosm exposures (96-h and 21-d laboratory bioassays and a 3-mo field microcosm) was conducted to compare the impacts of sediment-spiked cadmium on the mortality, development, and abundance of Chironomidae larvae. The 96-h and 21-d lethal concentrations of sediment-spiked Cd to 50% of the species Chironomus riparius were estimated to be 201.07 and 172.66 mg/kg, respectively. In the 21-d laboratory bioassay, the endpoints, including the development rate and emergence ratio, were compared, and the lowest-observed-effect concentration (LOEC) values were 325.8 and 10.7 mg/kg, respectively. The abundance, richness, and biomass of field-collected larvae were compared among the different treatments in the field microcosm, and it was found that the order of sensitivities using different endpoints was biomass (2.6/5.2 mg/kg of no-observed-effect concentration/LOEC) > diversity (10.7/21.2 mg/kg) > abundance (41.2/82.7 mg/kg). The toxicity values based on lethal/sublethal changes in the laboratory bioassays might not fully protect field organisms against damage from chemicals, such as Cd, unless an assessment factor of 5 is used. These findings highlight the need to conduct field validation of criteria/guidelines before they are introduced to protect organisms/ecosystems in the field and provide a preliminary template for future field validation of criteria elsewhere. Environ Toxicol Chem 2021;40:2450-2462. © 2021 SETAC.

In this study, three dominant bacteria Cellulomonas flavigena (Ⅰ), Cellulomonas flavigena (Ⅱ), Sphingomonas paucimobilis (Ⅲ) from Fire Phoenix rhizosphere soil were used to develop a multi-microbial agent system. For oil-contaminated soil in the Dagang oilfield, the immobilized test bacteria were inoculated into the Fire Phoenix rhizosphere soil to examine the effects of bacterial agents on polycyclic aromatic hydrocarbons (PAHs)-contaminated soil. The results showed that PAHs degradation was promoted under the ⅠⅢ (with an effective number of viable bacteria of 109 cfu·mL-1) and ⅠⅡⅢ (with an effective number of viable bacteria of 107 cfu·mL-1) treatments. The PAHs degradation rates were 32.2% and 41.4%, respectively, being significantly higher than that in the control treatments. The ⅠⅡⅢ treatment significantly promoted the belowground biomass of Fire Phoenix, which was 31.2% higher than that of the control treatment. Our results suggested that the multi-microbial agent constructed by the three dominant bacteria ⅠⅡⅢ could be used as a strengthening method for the remediation of PAHs-contaminated soil by Fire Phoenix, which provided a novel method for microbial enhanced phytoremediation technology.

采用生物炭吸附与表面活性剂淋洗联合修复PAHs污染场地土壤,通过外源添加700℃制备的稻壳生物炭,研究了添加生物炭对非离子型表面活性剂TX-100淋洗PAHs效果的影响;通过老化后的含芘高岭土模拟污染土壤,研究了生物炭吸附与TX-100淋洗联合修复的驱动机制.强化淋洗修复结果显示:TX-100浓度为10 g·L-1,淋洗时间为16h,固液比为1∶10,转速为150 r·min-1,对本研究选取的PAHs浓度为94.97 mg·kg-1的污染土壤的淋洗效果最好,解吸率达66.2％;添加1％土壤质量的稻壳生物炭,稳定14 d后,TX-100对PAHs解吸率从对照的66.2％提高到了80.6％ (P＜0.05),其中四环PAHs的解吸量占比最高(42.1％).高岭土模拟结果显示:添加1％土壤质量的生物炭14 d后,高岭土中芘含量从50 mg·kg-1降低至27.77 mg·kg-1,同时TX-100可以有效洗脱生物炭上吸附的芘,解吸率达80.2％.扫描电镜和光谱学分析显示:生物炭可以吸附TX-100,而被吸附的TX-100又会占据部分生物炭孔道,后者在1600 cm-1处的C=O和C=C吸收振动峰和1103～1025 cm-1处的C-O-C吸收振动峰明显减弱,进一步导致PAHs从固相向液相的迁移.因此,在表面活性剂淋洗修复前,添加生物炭可以显著提高土壤PAHs的解吸率.