摘要：
Exposure to organic ultraviolet (UV) filters has raised concerns due to their potential adverse effects on environments. However, their toxic mechanisms on plants remain elusive. In this study, using integrative physiological and transcriptomic approaches we investigated the physiological and molecular responses to three representative UV filters, namely oxybenzone (OBZ), avobenzone (AVB), and octinoxate (OMC), in an agricultural model plant tobacco. The exposure to UV filters disrupts the functionality of photosystem reaction centers and the light-harvesting apparatus. Concurrently, UV filters exert a suppressive effect on the expression of genes encoding Rubisco and Calvin-Benson cycle enzymes, resulting in a decreased efficiency of the Calvin-Benson cycle and consequently hampering the process of photosynthesis. Exposure to UV filters leads to significant generation of reactive oxygen species within tobacco leaves and downregulation of oxidoreductase activities. Moreover, UV filters promote abscisic acid (ABA) accumulation by inducing the expression of ABA biosynthesis genes whereas repress indole-3-acetic acid (IAA) biosynthesis gene expression, which induce leaf yellowing and slow plant growth. In summary, the organic UV filters exert toxic effects on tobacco growth by inhibiting chlorophyll synthesis, photosynthesis, and the Calvin-Benson cycle, while generating excessive reactive oxygen species. This study sheds light on the toxic and tolerance mechanisms of UV filters in agricultural crops.
作者机构：
[Peng, Chuan-Chong; Wu, LJ; Wu, Li-Jun; Long, Fang; Zhang, Kai-Yi; Liu, Jin-Hui] Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Peoples R China.;[Long, Fang] ChangSha Commerce & Tourism Coll, Dept Hunan Cuisine, Changsha 410116, Peoples R China.;[Feng, Rui] Capital Normal Univ, Dept Chem, Beijing 100089, Peoples R China.
通讯机构：
[Wu, LJ ] C;Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Peoples R China.
摘要：
A novel alkyl radical-initiated alkylsulfonylation of alkenes via copper carbene coupling is developed for the synthesis of various alkyl-alkyl sulfones by employing potassium metabisulphite (K2S2O5) as a connector. In this reaction, readily available K2S2O5 not only serves as a sulfur dioxide source but is also demonstrated to be an efficient reducing agent for promoting the catalytic cycle. Notably, the late-stage modifications of bioactive molecules including estrone and cholesterol derivatives utilizing this protocol could also be achieved. Mechanistic investigations reveal that the transformation involves intramolecular radical cyclization, insertion of "SO2" and the coupling of copper carbenes in a single reaction step. A novel alkyl radical-initiated alkylsulfonylation of alkenes involving copper carbene coupling is developed for the synthesis of various alkyl-alkyl sulfones by employing potassium metabisulphite (K2S2O5) as a connector.
通讯机构：
[Li, H ] C;Cent South Univ Forestry & Technol, Coll Forestry, Changsha, Peoples R China.;Key Lab Natl Forestry Grassland Adm Control Artifi, Changsha, Peoples R China.;Hunan Prov Key Lab Control Forest Dis & Pests, Changsha, Peoples R China.;Minist Educ, Key Lab Nonwood Forest Cultivat & Conservat, Changsha, Peoples R China.
关键词：
Colletotrichum fructicola;carbendazim;mechanism of resistance;β-tubulin isotypes
摘要：
Colletotrichum fructicola is the major pathogen of anthracnose in tea-oil trees in China. Control of anthracnose in tea-oil trees mainly depends on the application of chemical fungicides such as carbendazim. However, the current sensitivity of C. fructicola isolates in tea-oil trees to carbendazim has not been reported. Here, we tested the sensitivity of 121 C. fructicola isolates collected from Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangsu, and Jiangxi provinces in China to carbendazim. One hundred and ten isolates were sensitive to carbendazim, and 11 isolates were highly resistant to carbendazim. The growth rates, morphology, and pathogenicity of three resistant isolates were identical to those of three sensitive isolates, which indicates that these resistant isolates could form a resistant population under carbendazim application. These results suggest that carbendazim should not be the sole fungicide in control of anthracnose in tea-oil trees; other fungicides with different mechanisms of action or mixtures of fungicides could be considered. In addition, bioinformatics analysis identified two beta-tubulin isotypes in C. fructicola: Cf beta(1)tub and Cf beta(2)tub. E198A mutation was discovered in the Cf beta(2)tub of three carbendazim-resistant isolates. We also investigated the functional roles of two beta-tubulin isotypes. Cf Delta beta(1)tub exhibited slightly increased sensitivity to carbendazim and normal phenotypes. Surprisingly, Cf Delta beta(2)tub was highly resistant to carbendazim and showed a seriously decreased growth rate, conidial production, pathogenicity, and abnormal hyphae morphology. Promoter replacement mutant Cf Delta beta(2)-2x beta(1) showed partly restored phenotypes, but it was still highly resistant to carbendazim, which suggests that Cf beta(1)tub and Cf beta 2tub are functionally interchangeable to a certain degree.
摘要：
Thus far, the available works on sequencing flexibility in shop floor scheduling only consider the sequencing flexibility with serial operation constraint. However, the sequencing flexibility with discrete and hybrid operation constraints are also widely existed in the actual production and have significant impact on production efficiency. Therefore, this work proposes a distributed flexible job shop scheduling problem considering integrated sequencing flexibility (DFJSPS), in which the serial, discrete and hybrid operation constraints are considered simultaneously. A mixed integer linear programming model is proposed to solve the DFJSPS by using the CPLEX solver. Then, an efficient memetic algorithm (EMA) is designed with the objectives of minimizing makespan and total energy consumption. In the EMA, a five-layer coding method and an efficient initialization method are presented to obtain high quality initial solutions; and an efficient local search operator is designed to help the algorithm to improve its convergence speed. Comprehensive experiments show that the EMA outperforms other three well-known algorithms in most of the instances, demonstrating the superior performance of EMA for solving DFJSPS in terms of both computational efficiency and solution quality. In summary, the research fills the research gap on integrated sequencing flexibility in the field of shop floor scheduling; on the other hand, it can help production managers to obtain the efficient scheduling schemas in the decision-making systems about various types of sequencing flexibility.
摘要：
Enzymatic degradation of plastic is an effective means of plastic recycling and pollution control. However, the strong chemical inertness of polypropylene plastic (PP) severely impedes its oxidative cleavage, making it resistant to degradation. In this study, based on sequence screening of Hidden Markov Model (HMM), a dioxygenase (HIS1) was identified and characterized to be effective in PP oxidation. Various kinds of PP products, including plastic films, microplastics, and disposable water cups or bags, were HIS1-degraded with cracks and holes on the surface. The hydrophobic binding was the primary force driving oxidative degradation in the specific cavity of HIS1. The discovery of HIS1 achieved a zero breakthrough in PP biodegradation, providing a promising candidate for the selection and evolution of degrading enzymes.
期刊：
Forest Policy and Economics,2024年160:103146 ISSN：1389-9341
通讯作者：
Zhang, SH
作者机构：
[Zhang, Shouhong; Zhang, SH; Zhang, Fan; Ren, Yufei] Beijing Forestry Univ, Sch Soil & Water Conservat, Jixian Natl Forest Ecosyst Observat & Res Stn, CNERN, Beijing 100083, Peoples R China.;[Li, Mo] Northeast Agr Univ, Sch Water Conservancy & Civil Engn, Harbin 150030, Heilongjiang, Peoples R China.;[Zhang, Shouhong; Zhang, SH] Beijing Forestry Univ, State Key Lab Efficient Prod Forest Resources, Beijing 100083, Peoples R China.;[Liu, Jiakai] Beijing Forestry Univ, Sch Ecol & Nat Conservat, Beijing 100083, Peoples R China.;[Cao, Yini] Cent South Univ Forestry & Technol, Fac Life Sci & Technol, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Zhang, SH ] B;Beijing Forestry Univ, Sch Soil & Water Conservat, Jixian Natl Forest Ecosyst Observat & Res Stn, CNERN, Beijing 100083, Peoples R China.;Beijing Forestry Univ, State Key Lab Efficient Prod Forest Resources, Beijing 100083, Peoples R China.
关键词：
National Reserve Forest Project of China;Afforestation project;Carbon neutrality;Carbon sink;Carbon cost and price
摘要：
The National Reserve Forest Project (NRFP) is a forestry project launched by China in 2013 to ensure the safety of timber supply and create a carbon sink, which can contribute to China's future carbon neutrality goals. To evaluate the carbon neutral contribution and carbon sink benefits of the NRFP, it is necessary to estimate the carbon sink amount, carbon sink cost, and carbon sink price. A combined method, modified Hartman model, and Rubinstein-Stahl bargaining model were used to estimate and analyze the carbon sink amount, carbon sink cost, and carbon sink price of NRFPs from several typical NRFP zones to the nationwide level. Results show that: (1) if the yearly construction area of the NRFP keeps stable at 10.2 × 105 ha in the future, the carbon sink of NRFP will account for about 17.32%, 28.35%, and 80.00% of total carbon emissions in 2060 under low-, middle-, and high-policy scenarios, respectively, representing an increase compared to the current level of approximately 16%; (2) the weighted average carbon sink cost of NRFP is estimated to be 95.16 CNY/t CO2 e (lower than the average carbon sink cost of 150 CNY/t CO2 e), and several measures such as applying Public-private partnership investment (PPP), increasing project operation duration, and choosing construction areas with low farmland benefit can help further reduce carbon sink cost of NRRP; (3) the reasonable carbon sink price should fall between the carbon sink cost and marginal carbon emission reduction cost of enterprises, and increasing the carbon sink price has a positive impact on NRFP construction. NRFPs suffer economic losses in the present carbon trade market, but they will gradually become profitable with the rising carbon sink price in the future. Therefore, it is imperative to maintain or gradually expand the construction area, provide more financial support, and improve the carbon trading market of NRFPs.
期刊：
Geotechnical and Geological Engineering,2024年42(2):1505-1518 ISSN：0960-3182
通讯作者：
Chang-Ping Wen
作者机构：
[Huan-Xia Ren; Xiang Chen] School of Civil Engineering, Changde Vocational Technical College, Changde, People’s Republic of China;[Chang-Ping Wen] School of Civil Engineering, Central South University of Forestry and Technology, Changsha, People’s Republic of China
通讯机构：
[Chang-Ping Wen] S;School of Civil Engineering, Central South University of Forestry and Technology, Changsha, People’s Republic of China
摘要：
Helianthemum songaricum and H. ordosicum are two shrubs disjunctively distributed in Central Asia and northwestern China. For conservation purposes, we used genotyping by sequencing (GBS) to investigate the genetic diversity and genetic structure of their populations. Based on the GBS data, H. songaricum populations showed considerable genetic differences from H. ordosicum populations. Helianthemum songaricum populations also showed a stronger population genetic structure within the isolated valleys in the Tianshan Mountains than was seen in previous studies. We speculated that the two species may represent two cotemporal migration events between the Middle East and Central Asia/Ordos Plateau since the early Pliocene. Due to the intense uplift of the Tianshan Mountains in the late Pliocene, populations of H. songaricum were isolated in different valleys. Subsequently, the cold glacial climate during the Pleistocene intensified the in situ intraspecific differentiation of the species. Based on our single nucleotide polymorphism data, we propose habitat damage by anthropological activities, where the two species inhabit should be urgently prohibited by executive management. In addition, a nursery for germplasm resources should be urgently set up to culture adequate progenies for the purpose of expanding the populations.
摘要：
To improve the compatibility between Portland cement and bamboo fibre, bamboo fibres were modified by acetic acid and fermentation treatment and the modified bamboo fibres/Porland cement composites were prepared. The hydration curves of the bamboo fibres/Porland cement composites were measured and the area ratio under the cement hydration heat curve was used as the compatibility coefficient to evaluate the compatibility of bamboo fiber and cement. The hydration products at different hydration times were characterized by XRD, FTIR, and SEM. Moreover, the mechanical strengths of standard test blocks of Portland cement/bamboo fibre composites were tested to further verify the improved compatibility of bamboo fiber and Portland cement. The study shows that the compatibility between bamboo fibre and Portland cement was improved from 9% to 87%, the bending strength of Portland cement/bamboo fibre composite was increased from 638 N to 3678 N, and the compressive strength was increased from 1.5 MPa to 34.35 MPa.
摘要：
As a popular ornamental plant and an effective species for controlling rocky desertification, the identification and protection of potential habitats of Lagerstroemia excelsa habitats hold significant importance. To gain a comprehensive understanding of the natural resources and growing conditions for L. excelsa, predictive modeling was employed to estimate the potential geographical distribution of the species during the Mid-Holocene (MH), the present, and the years 2050 and 2070. The projection was based on current occurrences, and we selected the relevant environmental attributes through the Pearson analysis and the Maximum Entropy Model (MaxEnt). The analysis revealed that temperature and precipitation are the primary environmental factors influencing L. excelsa distribution, with the Wuling Mountains identified as a center distribution hub for this species. The anticipated suitable area for L. excelsa is expected to experience marginal expansion under future climate scenarios. These results are invaluable for guiding the protection and sustainable utilization of L. excelsa in the face of climate change. Additionally, the data generated can be leveraged for enhanced introduction, breeding, selection, and cultivation of L. excelsa, taking into account the challenges posed by global warming.
作者机构：
[Liu, Falin; Liu, FL; Chen, Hao] Cent South Univ Forestry & Technol, Coll Forestry, Changsha, Peoples R China.
通讯机构：
[Liu, FL ] C;Cent South Univ Forestry & Technol, Coll Forestry, Changsha, Peoples R China.
关键词：
Fire disturbance;Ecosystem recovery;Subtropical climate;Prescribed burning
摘要：
Soil water repellency (SWR) is a physical phenomenon whereby the surface of soil particles cannot be, or resists being, moistened by water. The recovery process of fire-induced SWR can provide important evidence for ecosystem resilience, but most existing studies ignored this process. Prescribed burning is a widely used method to reduce the risk of fire and fuel. However, prescribed fires can increase SWR, reducing infiltration and increasing overland flow and subsequent soil erosion. In order to understand the ecosystem resilience process from fire-induced SWR, soil samples were collected before and after prescribed burning. Four different forest types in the Hunan province of China were studied. Soil samples at four different soil depths (0-5, 6-10, 11-15, and >15 cm) and four time intervals (3, 30, 180, and 360 d) after burning at different intensities were collected. No significant difference in SWR was found among the four forest types, but the SWR of soil in plantations was stronger than that in secondary forests before fire. Most soil samples showed slightly increased SWR after burning, SWR increasing with fire intensity. Surface soil (0-5 cm) SWR showed greater sensitivity to fire disturbance than subsurface soil (>5 cm). SWR had a smaller scope of influence and shorter recovery period in burned secondary forests. Although SWR recovered over time, recovery was slower with increasing fire intensity. SWR always recovered to pre-fire levels given sufficient time. Our study revealed the recovery process of SWR, and explored the temporal and spatial mechanisms of forest ecosystem recovery after prescribed burning.
摘要：
Our results highlight the regulatory role of the negative bacterial‐fungal association in enhancing the correlation between bacterial diversity and C mineralisation. This suggests that promoting short‐term successive planting in the management of Eucalyptus plantations can mitigate the impact of this association on SOC decomposition. Taken together, our study advances the understanding of bacterial‐fungal negative associations to mediate carbon mineralisation in Eucalyptus plantations, giving us a new insight into SOC cycling dynamics in artificial forests. Abstract Bacteria and fungi are core microorganisms in diverse ecosystems, and their cross‐kingdom interactions are considered key determinants of microbiome structure and ecosystem functioning. However, how bacterial‐fungal interactions mediate soil organic carbon (SOC) dynamics remains largely unexplored in the context of artificial forest ecosystems. Here, we characterised soil bacterial and fungal communities in four successive planting of Eucalyptus and compared them to a neighbouring evergreen broadleaf forest. Carbon (C) mineralisation combined with five C‐degrading enzymatic activities was investigated to determine the effects of successive planting of Eucalyptus on SOC dynamics. Our results indicated that successive planting of Eucalyptus significantly altered the diversity and structure of soil bacterial and fungal communities and increased the negative bacterial‐fungal associations. The bacterial diversity significantly decreased in all Eucalyptus plantations compared to the evergreen forest, while the fungal diversity showed the opposite trend. The ratio of negative bacterial‐fungal associations increased with successive planting of Eucalyptus due to the decrease in SOC, ammonia nitrogen (NH4+‐N), nitrate nitrogen (NO3−‐N) and available phosphorus (AP). Structural equation modelling indicated that the potential cross‐kingdom competition, based on the ratio of negative bacterial‐fungal correlations, was significantly negatively associated with the diversity of total bacteria and keystone bacteria, thereby increasing C‐degrading enzymatic activities and C mineralisation. Synthesis and applications: Our results highlight the regulatory role of the negative bacterial‐fungal association in enhancing the correlation between bacterial diversity and C mineralisation. This suggests that promoting short‐term successive planting in the management of Eucalyptus plantations can mitigate the impact of this association on SOC decomposition. Taken together, our study advances the understanding of bacterial‐fungal negative associations to mediate carbon mineralisation in Eucalyptus plantations, giving us a new insight into SOC cycling dynamics in artificial forests.
期刊：
Science of The Total Environment,2024年906:167219 ISSN：0048-9697
通讯作者：
Wang, Ping;Zhu, J
作者机构：
[Zhou, Tao; Sun, Jikang; Xing, Qinqin] Cent South Univ Forestry & Technol, Coll Life Sci & Technol, 498 South Shaoshan Rd, Changsha 410004, Hunan, Peoples R China.;[Wang, Ping; Zhu, Jian; Zhu, J] Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, 498 South Shaoshan Rd, Changsha 410004, Peoples R China.;[Liu, Zhiming] Eastern New Mexico Univ, Dept Biol, Portales, NM 88130 USA.
通讯机构：
[Wang, P; Zhu, J ] C;Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, 498 South Shaoshan Rd, Changsha 410004, Peoples R China.
关键词：
Cd stress;Koelreuteria paniculata;KpMIPS;Resistance
摘要：
Cadmium (Cd) pollution in soil is an important factor endangering plant growth and harming human health through food chains. Koelreuteria paniculata is an important woody plant for ecological restoration of Cd-contaminated soils. In this study, KpMIPS gene of K. paniculata was cloned, and the expressed protein (60kDa) had 1-phosphate synthase activity. The results showed that KpMIPS significantly promoted root development of K. paniculata and Arabidopsis thaliana, reduced damage to the roots of Arabidopsis thaliana caused by Cd, and decreased transfer of Cd to the aboveground parts of K. paniculata and Arabidopsis thaliana . In the K. paniculata plants overexpressing KpMIPS integrity of the root cells was maintained and the content of pectin and phytic acid was significantly increased. Overexpression of KpMIPS increased the Cd accumulation in the roots and decreased the Cd content in the stems and leaves. Clearly, KpMIPS could regulate the contents of pectin and phytic acid in K. paniculata, thereby passivating Cd(2+) and enriching it in the root cell wall, reducing the transfer of free Cd(2+) to other parts of K. paniculata, and providing a positive regulatory effect on the Cd resistance of K. paniculata. The results of the study provide a technical introduction for the selection and genetic improvement of target genes regulating heavy metal resistance of plants in phytoremediation technology.
作者机构：
[He, Mei; Wang, Hongjie; Guan, Jilun; Cheng, Fangchao; He, M] Guangxi Univ, Sch Resources Environm & Mat, State Key Lab Featured Met Mat & Life cycle Safety, Nanning 530004, Peoples R China.;[Cheng, Fangchao] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Peoples R China.;[Zhu, YQ; Zhu, Yanqiu] Univ Exeter, Coll Engn Math & Phys Sci, Exeter EX4 4QF, England.
通讯机构：
[He, M; Cheng, FC ] G;[Zhu, YQ ] U;Guangxi Univ, Sch Resources Environm & Mat, State Key Lab Featured Met Mat & Life cycle Safety, Nanning 530004, Peoples R China.;Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Peoples R China.;Univ Exeter, Coll Engn Math & Phys Sci, Exeter EX4 4QF, England.
摘要：
Flexible sensors have promising applications in the fields of health monitoring and artificial intelligence, which have attracted much attention from researchers. However, the design and manufacture of sensors with multiple sensing functions (like simultaneously having both temperature and pressure sensing capabilities) still present a significant challenge. Here, an ionic thermoelectric sensor for synchronous temperature and pressure sensing was developed on the basis of a carbon microtubes (CMTs)/potassium chloride (KCl)/gelatin composite consisting of gelatin as the polymer matrix, CMTs as the conductive material and KCl as the ion source. The designed CMTs/KCl/gelatin composite with the good ductility (830%) and flexibility can achieve a Seebeck coefficient of 4 mV K-1 and a dual stimulus responsiveness to pressure and temperature. In addition, not only the movement of the human body (e.g., fingers, arms), but also the temperature difference between the human body and the environment, were able to be monitored by the designed CMTs/KCl/gelatin sensors. This study provides a novel strategy for the design and preparation of high-performance flexible sensors by utilizing ion-gel thermoelectric materials and promotes the research of temperature and pressure sensing technologies. Design of a CMTs/KCl/gelatin composite by a facile dissolution process using gelatin, CMTs and KCl for a wearable pressure and temperature sensor.
关键词：
Carbon density;Carbon accumulation rate;Forest age;Spatial variation;Cultural in fluence
摘要：
Understanding the spatial variation, temporal changes, and their underlying driving forces of carbon sequestration in various forests is of great importance for understanding the carbon cycle and carbon management options. How carbon density and sequestration in various Cunninghamia lanceolata forests, extensively cultivated for timber production in subtropical China, vary with biodiversity, forest structure, environment, and cultural factors remain poorly explored, presenting a critical knowledge gap for realizing carbon sequestration supply potential through management. Based on a large-scale database of 449 permanent forest inventory plots, we quantified the spatial -temporal heterogeneity of aboveground carbon densities and carbon accumulation rates in Cunninghamia lanceolate forests in Hunan Province, China, and attributed the contributions of stand structure, environmental, and management factors to the heterogeneity using quantile age -sequence analysis, partial least squares path modeling (PLS-PM), and hot -spot analysis. The results showed lower values of carbon density and sequestration on average, in comparison with other forests in the same climate zone (i.e., subtropics), with pronounced spatial and temporal variability. Specifically, quantile regression analysis using carbon accumulation rates along an age sequence showed large differences in carbon sequestration rates among underperformed and outperformed forests (0.50 and 1.80 Mg center dot ha ⠁1 center dot yr ⠁1). PLS-PM demonstrated that maximum DBH and stand density were the main crucial drivers of aboveground carbon density from young to mature forests. Furthermore, species diversity and geotopographic factors were the significant factors causing the large discrepancy in aboveground carbon density change between low- and high -carbon -bearing forests. Hotspot analysis revealed the importance of culture attributes in shaping the geospatial patterns of carbon sequestration. Our work highlighted that retaining largesized DBH trees and increasing shade -tolerant tree species were important to enhance carbon sequestration in C. lanceolate forests.
摘要：
Breathable and comfortable sensing textiles that can detect multi-biomarkers existing in human sweat are a promising way to achieve comprehensive health monitoring in our daily life. However, current wearable and flexible electrochemical textiles lack stretchability, which can result in unstable signals or device damage during movement. Additionally, these textiles have limited integration of multiple indicators, needing a large surface area and a significant amount of sweat to activate the sensors. Herein, we report an integrated all-in-one multifunctional electrochemical biosensor fiber constructed with a helical core-sheath structure, offering the stretchability and ability to detect biomarkers with trace amounts of sweat. The biosensor was fabricated by arranging multi-functionalized carbon nanotube strips in a spiral pattern alongside a pre-stretched polymer fiber core acting as microelectrodes with robust interface. Additionally, a super-hydrophilic sheath layer is incorporated to enhance the sweat capture efficiency of the biosensor. The biosensor has the capability to simultaneously monitor six biomarkers including pH, K+, Na+, glucose, lactate and uric acid, demonstrating stable sensing performance under 300% strain. Merely 1 of sweat is needed to initiate the detection of all six biomarkers. The resulting textile sensing system presents continuous and real-time monitoring of multi-biomarker information, allowing for the assessment of our health condition.
摘要：
Microplastics (MPs), a new type of pollutant, have attracted much attention worldwide. MPs are often complexed with other pollutants such as heavy metals, resulting in combined toxicity to organisms in the environment. Studies on the combined toxicity of MPs and heavy metals have usually focused on the marine, while on the freshwater are lacking. In order to understand the combined toxic effects of MPs and heavy metals in the freshwater, five typical MPs (PVC, PE, PP, PS, PET) were selected to investigate the adsorption characteristics of MPs to Pb(2+) before and after the MPs aging by ultraviolet (UV) irradiation through static adsorption tests. The results showed that UV aging enhanced adsorption of Pb(2+) by MPs. It is noteworthy that MPs-PET had the highest adsorption capacity for Pb(2+), and the interaction between MPs-PET and Pb(2+) was the strongest. We specifically selected MPs-PET to study its combined toxicity with Pb(2+) to Chlorella pyrenoidosa. In the combined toxicity test, MPs-PET and Pb(2+) had significant toxic effects on Chlorella pyrenoidosa in the individual exposure, and the toxicity of individual Pb(2+) exposure was greater than that of individual MPs-PET exposure. In the combined exposure, when MPs-PET and Pb(2+) without adsorption (MPs-PET/Pb(2+)), MPs-PET and Pb(2+) had a synergistic effect, which would produce strong physical and chemical stress on Chlorella pyrenoidosa simultaneously, and the toxic effect was the most significant. After the adsorption of MPs-PET and Pb(2+) (MPs-PET@Pb(2+)), the concentration and activity of Pb(2+) decreased due to the adsorption and fixation of MPs-PET, and the chemical stress on Chlorella pyrenoidosa was reduced, but the physical stress of MPs-PET still existed and posed a serious threat to the survival of Chlorella pyrenoidosa. This study has provided a theoretical basis for further assessment of the potential environmental risks of MPs in combination with other pollutants such as heavy metals.
