Located in the transitional zone of three major natural regions in China， Gansu Province serves as a critical area for investigating vegetation dynamics in response to climate change and human activities， providing a scientific basis for regional vegetation conservation and ecological engineering policies. Based on normalized difference vegetation index （NDVI） data and influencing factors datasets from 2001 to 2021， this study employed Theil-Sen Median trend analysis， partial correlation analysis， spatial autocorrelation analysis， and residual analysis to systematically analyze the spatiotemporal variations of vegetation NDVI and their driving mechanisms in Gansu Province. The results indicate that： ① The mean NDVI value during the study period was 0.352， exhibiting a distinct "high in the southeast， low in the northwest" spatial pattern. Both the entire province and individual geomorphic units showed significant upward trends， with 74.25% of the area experiencing vegetation improvement， particularly pronounced in the Loess Plateau of Longzhong and the southern mountainous regions. ② Climatic factor analysis revealed that temperature and precipitation exerted positive effects on vegetation NDVI in over 66% of the study area， with precipitation demonstrating a stronger influence than temperature. ③ Human activities predominantly enhanced vegetation NDVI， with stable grassland and cropland areas contributing the most （cumulatively 60%）. The change rates of nighttime light （NTL） and NDVI exhibited a weak positive spatial correlation， displaying "low-low" clustering in the Gannan Plateau， Hexi Corridor， Qilian Mountains， and Beishan Mountains， while "low-high" clustering characterized the southern mountainous area of Gansu and the Loess Plateau in central Gansu. ④ Contribution analysis highlighted that human activities （70.61%） had a greater overall impact on vegetation changes than climate change （29.39%）， though spatial heterogeneity was evident-the Gannan Plateau was the only geomorphic unit where climate change dominated. These findings elucidate the differential driving mechanisms of vegetation dynamics in transitional zones and offer critical insights for optimizing regional ecological management strategies.

Assessing soil organic matter (SOM) stability is crucial for evaluating the quality of reclaimed carbon pools. Herein, we integrated Fourier transform infrared (FT-IR) spectroscopy, high-throughput sequencing, and physicochemical assays to investigate SOM stability and its driving factors in reclaimed coal gangue soils. Reclamation treatments significantly increased soil organic carbon (SOC) contents by 40 %-71 % (8.62-8.78 g/kg) compared to the control (5.12 g/kg). However, this carbon accumulation coincided with a substantial reduction in soil aggregate stability, indicated by decreases of 16 %-28 % in mean weight diameter (MWD), and 18 %-43 % in geometric mean diameter (GMD). Compared to the control, reclaimed treatments exhibited a slight but nonsignificant decrease in SOM decomposition degree (Degree), defined by the FT-IR derived aromatic-C/aliphatic-C ratio; this ratio reflects SOM stability due to the high recalcitrance of aromatic-C and the lability of aliphatic-C toward microbial breakdown. Correlation analysis further revealed Degree was positively correlated with MWD, GMD, soil pH, but negatively correlated with SOC content and fungal richness. These relationships highlight a critical dynamic in reclamation: the rapid input of exogenous organic matter dominates the soil carbon pool, exceeding the rate of its microbial conversion to stable forms. Collectively, our findings demonstrated a decoupling process between the quantity (carbon accumulation) and the quality (carbon pool stability) of sequestered carbon. This study provides a mechanistic framework for assessing carbon sequestration and underscores the necessity for management practices that not only enhance carbon input but also promote its chemical stabilization and physical protection in engineered post-mining landscapes.

As a solidified material, iron salt has a good effect on the remediation of soil antimony （Sb） pollution, but its improper use will cause soil acidification and reduce the remediation effect. The ferric sulfate cornerstone ash-reinforced passivation material （FS） and the polyferric sulfate cornerstone ash-reinforced passivation material （PFS） were prepared by using ferric sulfate, polyferric sulfate, and quicklime as raw materials. The morphology and characteristics of the materials were analyzed using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and Fourier transform infrared spectroscopy （FTIR）. The adsorption mechanism and remediation effect of the two materials on soil Sb were studied by an adsorption experiment and a soil culture experiment. The results showed that FS and PFS were mainly composed of iron and calcium oxides and hydroxides, which contained hydroxyl, carbonyl, and other functional groups. The Freundlich model fitted the isothermal adsorption data well, indicating that the adsorption of Sb （Ⅲ） by both materials was multilayer adsorption. The adsorption capacity of Sb （Ⅲ） by FS and PFS increased with the increase in materials added. The pseudo-second-order kinetic model fitted the adsorption kinetics of FS and PFS well. Among the coexisting ions, PO43- had the greatest effect on the adsorption of Sb （Ⅲ） by FS and PFS, and the presence of a high concentration of （0.1 mol·L-1） PO43- significantly inhibited the adsorption of Sb （Ⅲ） by FS and PFS. In the presence of low concentrations （0.01 mol·L-1 and 0.001 mol·L-1） of PO43-, the adsorption of Sb （Ⅲ） by FS and PFS was promoted. The addition of FS and PFS could reduce the total Sb （T） and trivalent Sb （Ⅲ） contents of extractable citric acid in the soil. The soil culture experiment showed that adding 5% FS and PFS could reduce the exchangeable Sb content in heavily polluted soil by 66.39% and 72.88%, respectively, and reduce the exchangeable Sb content in mildly polluted soil by 56.04% and 56.86%, respectively. Soil pH and electrical conductivity （EC） increased significantly with the increase in material addition. In conclusion, FS and PFS had efficient adsorption properties for both aqueous solution and soil Sb, and application in acidic soil could significantly improve soil pH, indicating that both materials could effectively passivate soil Sb and alleviate soil acidification and have great potential in passivating remediation of Sb-polluted soil.

Ecological risk assessments typically prioritize direct toxicity, often overlooking indirect cascades that reshape ecosystem function. By incubating field-collected litter in a standardized, metal-free environment, we assessed the integrated 'litter legacy' (encompassing pollution-altered substrate quality and resident microbes) independent of direct soil toxicity. We found that litter from polluted sites exerted a strong constraint on decomposition, driven by a dual legacy: a shift in resource stoichiometry (characterized by a stress-induced low C:N ratio) and a pre-simplified fungal community. Specifically, this legacy effect acted as a selective filter that perpetuated the loss of fungal diversity and specialized decomposers, while bacterial communities showed high functional redundancy. Structural equation modeling revealed that this fungal diversity loss, maintained by the litter legacy, was the primary driver of functional decline. Our study highlights that the 'resource-mediated legacy' acts as a persistent ecological filter that decouples soil improvement from functional recovery, suggesting that restoring the functional integrity of polluted ecosystems requires strategies that explicitly address plant defense traits and fungal community re-establishment.

Heavy metal contamination, particularly cadmium (Cd), poses a significant global environmental threat. Phytoremediation, which utilizes plants for heavy metal removal, offers a sustainable remediation strategy. However, its efficiency is often limited by plant growth and metal uptake capacity. This study investigates whether combined applications of indole‐3‐acetic acid (IAA), brassinosteroid (BR), and kinetin (KT) can enhance Cd phytoremediation in Bidens pilosa , a known Cd‐hyperaccumulator. A pot experiment was conducted using a completely randomized design with nine treatments, including individual and combined hormone applications under controlled high Cd stress (40 mg/kg). Here, we show that a combined IAA + BR treatment synergistically increased the Cd bioconcentration factor by 1.41‐fold compared to the control. This was accompanied by enhanced biomass, photosynthetic activity, and antioxidant enzyme activity (catalase [CAT] and peroxidase [POD]). The triple combination (IAA + KT + BR) synergistically increased the translocation factor by 1.38‐fold, indicating enhanced Cd movement to shoots, while other combinations exhibited additive or antagonistic effects on Cd accumulation, specifically in leaf and root tissues. Individual hormone applications generally maintained photosynthetic efficiency, whereas combinations often reduced it. These findings demonstrate that tailored phytohormone combinations can significantly enhance Cd phytoremediation efficacy in B. pilosa through modulation of key physiological responses. By optimizing plant growth and Cd partitioning, this hormone application approach offers an effective strategy for remediating Cd‐contaminated soils. Further research should focus on addressing cost limitations, particularly for BR, and evaluating the long‐term efficacy and ecological impacts of phytohormone treatments under field conditions.

This study systematically addresses three key challenges in conventional molecular imprinting technology involving catalytic substrate agglomeration, interfacial instability between organic and inorganic components, and imprinted layer delamination, through innovative nano-activated carbon (AC) interface engineering. We successfully developed an advanced molecularly imprinted catalyst (AC-MNC@MIP) by strategically integrating Fe3O4 magnetic nanofluid with a precisely tailored molecular imprinting polymer layer. The composite material exhibited a well-defined architecture featuring core Fe3O4 magnetic nanoparticles, on which AC was firmly anchored through its surface functional groups (C-O, COOH), resulting in a highly uniform dispersion (78-200 nm particle size distribution) with exceptional structural integrity. Performance evaluations demonstrated remarkable catalytic enhancement: the observed rate constant (kobs) showed a 2.5-fold improvement, while maintaining excellent stability with less than 3 % activity loss. Detailed mechanistic investigations revealed that the Fe3O4 nanoparticles synergistically interacted with C=O functional groups to facilitate the generation of reactive oxygen species (1O2 and SO4 center dot-), which enabled highly selective oxidation of sulfamethoxazole (SMX). This research established a robust and economically viable approach for constructing stable organic-inorganic hybrid interfaces in molecularly imprinted catalysts, while providing an effective solution for the targeted degradation of persistent, low-concentration environmental pollutants.

The pore confinement environment critically restricts mass transfer efficiency in advanced oxidation process (AOPs). Hydrothermal carbons with hierarchical pore architectures significantly influence mass transfer of substances in AOPs, resulting in notable differences in performance. In this study, Fe-modified spent coffee grounds hydrothermal carbon (Fe@SCGSHC) contains Fe2+ active sites, was synthesized using coffee grounds. We systematically compared the mass transfer and activation differences between persulfate (PMS) and hydrogen peroxide (H2O2) within a confinement pore environment, elucidating a micropore-mediated regulatory mechanism for performance of dual oxidizers. The diffusion constant of H2O2 (Kd2 = 0.1953 mg/g center dot min1/2) was 466 times greater than that of PMS (Kd2 = 0.000419 mg/g center dot min1/2). Besides, the oxidation rate constant of H2O2 increased from 0.026 to 8.481 (mg/L)-1 center dot h-1. 0.1 g Fe@SCGSHC achieved 100 % degradation of 5 mg/L sulfamethoxazole (SMX) within 5 min. The mechanistic study showed that the microporous structure enhances the Fe2+/Fe3+ cycling within confined spaces, accelerating reaction kinetics and shifting traditional Fe-based catalysts from radical pathways (SO4 center dot-, center dot OH) to singlet oxygen (1O2) pathways, revealing the selective advantage of micropores for H2O2activation to generate 1O2.The stability experiments results indicated that 0.01 g Fe@SCGSHC achieved a 70.71 % removal of total organic carbon (TOC) in 5 mg/L SMX aquatic environments, exhibiting good anti-interference capability and ecological safety. In conclusion, the adoption of an appropriate pore structure can enhance the mass transfer efficiency of AOPs, leading to the effective degradation of pollutants. This study provides a scientific foundation for the preparation and modification of hydrothermal carbon and the mass transfer of substances in AOPs.

Brown rice and rice bran, which contain higher levels of minerals than commonly consumed milled rice, are often considered better for addressing widespread mineral deficiencies. However, their effectiveness in providing bioaccessible minerals remains unclear. This study aimed to compare the contributions of essential elements (Ca, Fe, Zn, Mg, Mn, Cu) to recommended nutrient intake (RNI) and the risk associated with As exposure via consumption of brown rice, milled rice, and rice bran, based on elements bioaccessibility. The results indicated that essential elements retention in milled rice was significantly lower compared to brown rice, with percentages ranging from 22.3 % for Mg to 77.6 % for Zn. Although rice bran contained a substantial proportion of essential elements, the extremely low bioaccessibility of essential elements in rice bran (almost < 5 % for Ca, Fe, Zn) rendered it ineffective for micronutrient supplementation. Furthermore, the intake of Ca and Fe from both brown and milled rice was also minimal (< 5 % of RNI). Notably, milled rice yielded about 2.7 times bioaccessible Zn than brown rice, making it a superior option for Zn-deficient populations, despite its contribution to the RNI of Zn remaining insufficient. By contrast, brown rice was more beneficial for Mg intake, accounting for nearly half of RNI; however, brown rice also presented 1.6 times bioaccessible As compared to milled rice. This study highlights the importance of incorporating elements bioaccessibility to systematically assess both the nutritional benefits and potential risks associated with different rice products, thereby providing valuable insights for developing rice consumption guidelines.

Atmospheric deposition of Cd poses a serious threat to ecosystem security. Biochar is widely used for polluted soil remediation, however, whether biochar already applied to the soil can reduce the hazards of newly deposited Cd remains to be studied. Thus, an indoor cultural experiment and static adsorption method were conducted to study the isothermal and kinetic adsorption processes of three types of biochar (rice husk, rubber wood, and tobacco stem biochars) on Cd in iron rich soils and the effect of biochar on the morphological distribution of Cd in the soil and the soil pH. The results showed that the soil with biochar in our study could quickly fix “the new deposited Cd” in the soil in 3 h with the maximum adsorption capacity in rubber wood biochar-treated sample (3227.34 mg/kg）. The addition of all three biochar treatments significantly increased the soil pH and reduced the soil exchange state Cd content, with a 13.69–17.32% increase in the pH and a 13.22–54.39% reduction in the exchange state Cd content when contrasted with the control, which could promote those Cd converting into unavailable Cd (carbonate-bound form Cd, Fe-Mn oxide-bound form Cd, or residual form Cd) for crops. In summary, the addition of three kinds of biochar treatments could effectively reduce the ecological and environmental risk of soil that was contaminated by Cd and could provide a reliable theoretical basis for the effect of biochar on the improvement of the quality of soil that is contaminated by heavy metals.

Melatonin acts as a potential regulator of cadmium (Cd) tolerance in rice. However, its practical value in rice production remains unclear. To validate the hypothesis that melatonin affects Cd accumulation and rice quality, a series of experiments were conducted. The results showed that exogenous melatonin application was associated with reduced Cd accumulation (23-43%) in brown rice. Fourier transform infrared spectroscopy (FTIR) analysis showed that exogenous melatonin affected the rice protein secondary structure and starch short-range structure. Metabolomics based on LC-MS/MS revealed that exogenous melatonin altered the brown rice metabolic profile, decreased fatty acid metabolite content, but increased amino acid metabolite, citric acid, melatonin biosynthetic metabolite, and plant hormone contents. These findings indicate that exogenous melatonin can effectively reduced Cd accumulation and improve rice quality through metabolic network regulation, serving as an effective treatment for rice cultivated in Cd-contaminated soil.

Heavy metal stress can lead to slow growth and dwarfing of hyperaccumulators, limiting their effectiveness in remediating soil heavy metal pollution. Nitrogen (N) and phosphorus (P) fertilization can enhance plant growth, biomass, and stress resistance. We hypothesize that N and P fertilization could improve the soil heavy metal remediation efficiency of Bidens pilosa (B. pilosa). We conducted a greenhouse experiment with four treatments: control (CK), nitrogen fertilization (NF), phosphorus fertilization (PF), and nitrogen and phosphorus fertilization (NPF). Then, we analyzed the growth status, heavy metal content, and accumulation of B. pilosa under various treatments to explore the impact of N and P fertilization on its potential to remediate soil heavy metal pollution. The shoot height, root length, and shoot biomass of B. pilosa significantly improved under NF and NPF treatments (P<0.05). The root tolerance index of B. pilosa in the NF and NPF treatments also increased, exceeding 1. The NF and NPF treatments significantly increased the accumulation of heavy metals Cd, Cu, and Pb in the shoots of B. pilosa (P<0.05). The transfer coefficient of these heavy metals also increased in the NF and NPF treatments. Accordingly, N and NP fertilization can promote the growth of B. pilosa, increase the accumulation of heavy metals Cd, Cu, and Pb in B. pilosa, and improve the remediation efficiency of these heavy metals. In the context of rising global soil heavy metal pollution, our findings indicate that B. pilosa can aid in the remediation of soil heavy metal pollution.

Soil copper (Cu) pollution is a serious environmental risk in the Panax notoginseng planting area. However, the effect of Cu on soil microbial metabolism and nutrient cycling in this area remains unknown. Therefore, Biolog ECO-plate and enzyme stoichiometry methods were utilized in this study to investigate the impact of exogenous Cu (control: 0 mg·kg−1; Cu100: 100 mg·kg−1; Cu400: 400 mg·kg−1; and Cu600: 600 mg·kg−1) on the metabolic function of soil microbial and nutrient limitation in the P. notoginseng soil. The results indicated that Cu100 significantly increased soil organic carbon (SOC), total phosphorus (TP), soil C:N, microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) 9.89%, 15.65%, 17.91%, 61.87%, and 90.56% higher than the control, respectively. Moreover, the carbon source utilization ratio of carbohydrates, amino acids, and amphiphilic compounds of Cu100 also increased by 7.16%, 25.47%, and 84.68%, respectively, compared with the control. The activities of β-1,4-glucosidase, cellobiohyrolase, leucine amino peptidase, β-1,4-N-acetylglucosaminidase, and phosphatase significantly decreased with increasing Cu concentration. Soil enzyme stoichiometry showed that all treatments were limited by nitrogen (vector angle < 45°; 19.045–22.081). Cu600 led to the lowest carbon limitation (1.798) and highest carbon use efficiency (CUE:0.267). The PLS-SEM model also showed that MBC, MBN, MBP, and microbial diversity positively affected carbon and nitrogen limitation (0.654 and 0.424). Soil carbon, nitrogen, phosphorus, stoichiometric ratio, MBC, MBN, and MBP positively affected CUE (0.527 and 0.589). The microbial diversity index significantly negatively affected CUE (−1.490). Multiple linear stepwise regression analyses showed that CUE was mainly influenced by MBC, AP, C:P, and LAP. Thus, P. notoginseng soil can benefit soil microbial carbon and nitrogen limitations at low Cu concentrations. Clarifying the metabolic activity and nutritional status of microorganisms under Cu stress can provide some theoretical basis for realizing China's comprehensive and effective management and control policies for environmental risks from metals by 2035.

Graphene-based material is widely used to remove arsenic from water due to its layered structure with high surface area. Here, we have successfully synthesized Fe-La bimetallic modified graphite sheet materials to more efficiently remove As(III) from aqueous solution. The results showed that Fe-La-graphite sheets (FL-graphite sheets) have a larger specific surface area (194.28 m 2 ·g −1 ) than graphite sheets (2.80 m 2 ·g −1 ). The adsorption capacity of FL-graphite sheets for As(III) was 51.69 mg·g −1 , which was higher than that of graphite sheets (21.91 mg·g −1 ), La-graphite sheets (26.06 mg·g −1 ), and Fe-graphite sheets (40.26 mg·g −1 ). The FL-graphite sheets conformed to the Freundlich and Dubinin–Radushkevich isotherm, and the maximum adsorption capacity was 53.62 mg·g −1 . The removal process obeys intra-particle diffusion and pore diffusion for As(III). The results of batch adsorption experiments and characterization analyses demonstrated that oxidation, ligand exchange, and inner sphere complexation mechanisms involved in the adsorption of FL-graphite sheets to As(III) in comparison with graphite sheets. In addition, electrostatic attraction mechanism was found vital in the adsorption. Ecotoxicity assessment revealed that FL-graphite sheets have little influence on rice germination and growth, but reduced the toxicity of As(III) to rice. Therefore, the FL-graphite sheets have good practical application value in purifying As(III) polluted water with litter ecotoxicity.

The remediation of soil contaminated with cadmium (Cd) and arsenic (As) has consistently been a complex issue. Foliar application of jasmonic acid (JA) could be a promising agronomic practice for reducing heavy metal accumulations. However, the combined reduction effects and mechanisms of Cd and As in rice through foliar JA application have not been fully explored. In this study, a pot experiment was conducted to investigate rice yield, Cd and As accumulations and translocations, photosynthesis, and ROS-scavenging attributes in Huanghuazhan (HHZ) and Huarun No.2 (HR). The results revealed that 1μM JA treatment significantly decreased the concentrations of Cd (by 34.6% in HHZ and 38.3% in HR) and As (by 30.8% in HHZ and 40.8% in HR) in the grains, and increased the percentage of filled-grain and 1000-grain weight in HHZ. The structural equation model (SEM) indicated that grain Cd was directly and positively affected by panicle Cd and leaf sheath Cd, while grain As was directly and positively affected by panicle As, leaf blade As and leaf sheath As. JA application enhanced the net photosynthetic rate and chlorophyll content (both a and b). Additionally, it scavenged levels of H2O2 and O2.-, reduced lipid peroxidation damage by promoting the activities of antioxidant enzymes and altering the cellular redox status in the flag leaves of rice. Overall, these results suggest that foliar JA application of could be an effective strategy for preventing Cd and As accumulations in rice grains in paddy soils with low to medium contamination risks.

Modified multifunctional carbons (MMCs) have emerged as efficacious catalysts for persulfate, adept at degrading trace levels of emerging contaminants (ECs) in aquatic systems. The review provides a comprehensive analysis of the contemporary research on ECs degradation, emphasizing preparation techniques, catalytic mechanisms, environmental footprints, and the challenges inherent to MMCs. The analysis result suggest that enhancing mass transfer in MMCs through targeted modification and doping is essential for boosting the efficiency of ECs degradation. The complementary interaction between MMCs and advanced oxidation processes (AOPs) offers a potent and environmentally benign strategy for degradation. However, the practical application of MMCs is confronted with challenges such as sustainable synthesis, stability, recyclability, potential ecotoxicity, and migration risks. The mechanisms of persulfate catalysis by MMCs warrant thorough investigation,

To investigate the effect of exogenous application of melatonin (MT) on rice seedlings under antimony (Sb) stress, hydroponic experiments were carried out with rice seedlings (Huarun No.2). The fluorescent probe localization technology was used to locate the reactive oxygen species (ROS) in the root tips of rice seedlings, and the root viability, malondialdehyde (MDA) content, ROS (H2O2 and O2-·) content, antioxidant enzyme (SOD, POD, CAT, and APX) activities, and antioxidant (GSH, GSSG, AsA, and DHA) contents in the roots of rice seedlings were analyzed. The results showed that exogenous addition of MT could alleviate the adverse effects of Sb stress on the growth and increase the biomass of rice seedlings. Compared with the Sb treatment, the application of 100 μmol·L-1 MT increased rice root viability and total root length by 44.1% and 34.7% and reduced the content of MDA, H2O2, and O2-· by 30.0%, 32.7%, and 40.5%, respectively. Further, the MT treatment increased the activities of POD and CAT by 54.1% and 21.8%, respectively, and also regulated the AsA-GSH cycle. This research indicated that exogenous application of 100 μmol·L-1MT can promote the growth and antioxidant ability of rice seedlings and alleviate the damage of lipid peroxidation by Sb stress, thus improving the resistance of rice seedlings under Sb stress.

Arsenic (As) is a common environmental pollutant that seriously interferes with the normal growth of organisms. There is an urgent need to take environment-safe and efficient strategies to mitigate As toxicity. Melatonin (MT) is a pleiotropic molecule that regulates plant growth and organ development and alleviates heavy metal stresses. The experiment aims to explore the mechanism of MT in reducing arsenite toxicity by hydroponic rice seedlings. The results showed that MT application reduced the As content in rice roots and shoots by 26.4% and 37.5%, respectively, and mainly decreased As content in the soluble fractions of the rice root cell. MT application also increased the As content of chelated-soluble pectin and alkali-soluble pectin in the cell wall by 14.7% and 74.4%, respectively. It promoted the generation of the functional group of the root cell walls by the FTIR analysis, indicating that MT may promote the fixation of As on the cell wall. Meanwhile, MT contributed to scavenging excess H2O2, reducing MDA content, and maintaining normal morphology of root cells by stimulating SOD, POD and CAT activities and increasing the level of GSH. The research deepens our understanding of how MT participates in maintaining redox homeostasis in rice cells, reducing As toxicity, and decreasing As concentration in rice seedlings, thereby providing more possibilities for reducing As accumulation in rice.

基于利用植物提高Cd和As复合污染农田修复效率的目标,通过大田试验方法探究了乙二胺四乙酸(EDTA)、皂素(SAP)、柠檬酸(CA)和苹果酸(MA)对商陆萃取农田土壤Cd和As的影响.结果表明,施用4种不同螯合剂和有机酸对商陆的生长没有产生不利影响,且可以显著影响商陆对土壤Cd和As的吸收积累.与对照组相比,EDTA、SAP、CA和MA处理60d后导致商陆叶片Cd含量分别提高116.4%、55.0%、81.5%和109.9%,商陆地上部Cd积累量提高40.4%～106.0%,商陆地上部As积累量提高15.8%～55.1%.商陆各器官Cd和As的富集系数和转运系数也受螯合剂和有机酸施用的影响.施用EDTA、SAP、CA和MA均对商陆根际土壤Cd和As含量产生显著影响,SAP处理对降低商陆根际土壤Cd含量的影响最显著,而MA处理对降低商陆根际土壤As含量的影响最显著.研究表明,EDTA、SAP、CA和MA均可提高商陆萃取农田土壤Cd和As的效率,尤其是EDTA和MA的效果更好.

为探寻叶面喷施2,3-二巯基丁二酸(DMSA)降低水稻幼苗茎叶镉含量的潜在机制,在人工气候室内,采用水培实验方法研究了镉在幼苗不同部位的累积情况及喷施DMSA对镉胁迫的影响.结果表明:随着DMSA喷施浓度增加,茎基镉含量呈显著增加趋势,当DMSA喷施浓度达到1.0 mmol·L-1时茎基镉含量与对照(不喷施DMSA)处理相比显著增加57.3％,同时镉由茎基向地上部的转移效率降低52.7％.在此基础上,探寻了镉在茎基细胞中的赋存形态及镉的亚细胞分布情况,结果表明茎基中难溶态镉含量与对照处理相比显著增加了80.8％,细胞壁中镉含量达到对照处理的2.1倍.进一步对细胞壁各组分镉含量进行测定发现,果胶组分中镉含量随着DMSA喷施浓度增加呈现出显著升高趋势,与对照处理相比最高增加99.5％.此外,喷施DMSA后茎基中总植物螯合素(PCs)和谷胱甘肽(GSH)含量均呈现出显著增加趋势,最高分别达到对照处理组的2.2倍和3.1倍.喷施DMSA显著缓解了镉胁迫,幼苗地上部超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性分别升至对照处理的3.0倍和2.7倍,荧光标记试验表明叶片中过氧化氢含量随DMSA喷施浓度增加呈现显著降低趋势.研究表明,喷施DMSA显著增加了水稻幼苗茎基巯基化合物含量,从而提高了对镉的拦截能力,降低了镉由茎基向幼苗地上部转运效率,使水稻幼苗地上部镉含量显著降低,同时喷施DMSA还可显著缓解幼苗镉胁迫.

Antimony (Sb) is a hazardous metal element that is potentially toxic and carcinogenic. Melatonin (MT) is an indole compound with antioxidant properties that plays an essential role in plant growth and alleviates heavy metal stresses. Nevertheless, little is known about the effects and mechanisms of exogenous MT action on rice under Sb stress. The aim of this experiment was to explore the mechanism of MT reducing Sb toxicity in rice via hydroponics. The results showed that Sb stress significantly inhibited the growth of rice, including biomass, root parameters, and root viability. Exogenous MT obviously alleviated the inhibition of Sb stress on seedling growth and increased biomass, root parameters, and root viability by 15–55%. MT significantly reduced the total Sb content in rice and the subcellular Sb contents in roots by nearly 20–40% and 12.3–54.2% under Sb stress, respectively. MT significantly decreased the contents of malondialdehyde (MDA, by nearly 50%), ROS (H2O2 and O2·−, by nearly 20–30%), and RNS (NO and ONOO−) in roots under Sb stress, thus reducing oxidative stress and cell membrane damage. Furthermore, MT reversed Sb-induced phytotoxicity by increasing the activities of antioxidant enzymes (SOD, POD, CAT, and APX) by nearly 15% to 50% and by regulating the AsA–GSH cycle. In conclusion, this study demonstrates the potential of MT to maintain redox homeostasis and reduce Sb toxicity in rice cells, decreasing the content of Sb in rice and thereby alleviating the inhibition of Sb on rice growth. The results provided a feasible strategy for mitigating Sb toxicity in rice.