Mitigation of Cadmium and Copper Stress in Lettuce: The Role of Biochar on Metal Uptake, Oxidative Stress, and Yield

Biochar has emerged as a promising soil amendment for mitigating heavy metal contamination in agricultural systems. This study investigates the effects of biochar on cadmium (Cd) and copper (Cu) uptake, plant growth, oxidative stress, and physiological responses in lettuce (<i>Lactuca sativa&l...

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Main Authors: Riccardo Fedeli, Zhanna Zhatkanbayeva, Rachele Marcelli, Yerlan Zhatkanbayev, Sara Desideri, Stefano Loppi
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/14/15/2255
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author Riccardo Fedeli
Zhanna Zhatkanbayeva
Rachele Marcelli
Yerlan Zhatkanbayev
Sara Desideri
Stefano Loppi
author_facet Riccardo Fedeli
Zhanna Zhatkanbayeva
Rachele Marcelli
Yerlan Zhatkanbayev
Sara Desideri
Stefano Loppi
author_sort Riccardo Fedeli
collection DOAJ
description Biochar has emerged as a promising soil amendment for mitigating heavy metal contamination in agricultural systems. This study investigates the effects of biochar on cadmium (Cd) and copper (Cu) uptake, plant growth, oxidative stress, and physiological responses in lettuce (<i>Lactuca sativa</i> L.) plants exposed to different metal concentrations. Results indicate that biochar significantly influenced Cd bioavailability, reducing its accumulation in plant tissues by up to 31.9% and alleviating oxidative stress, with malondialdehyde and proline levels decreasing by up to 51.0% and 60.2%, particularly at higher application rates (5%). Cd-exposed plants treated with biochar exhibited an improved fresh weight (+22.6%), lower malondialdehyde and proline levels, and enhanced the chlorophyll content (+14.9% to 24.1%) compared to untreated plants. The bioaccumulation factor for Cd decreased (up to 31.8%) while the immobilization index (II) increased, confirming the role of biochar in limiting Cd mobility in soil. In contrast, Cu uptake remained consistently low across all treatments, with a significant reduction observed only at higher contamination levels (up to −34.2%). Biochar contributed to Cu immobilization, reflected in increased II values, and enhanced the plant biomass and chlorophyll content under Cu exposure (+15.4% and up to +24.1%, respectively), suggesting a partial alleviation of Cu toxicity. These findings highlight biochar’s potential in heavy metal remediation, particularly for Cd, by reducing bioavailability and improving plant resilience. However, its role in Cu-contaminated soils is mainly through immobilization rather than uptake reduction.
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publishDate 2025-07-01
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spelling doaj-art-a66c7581ee5543f4ba98b8e9dcc4e9a42025-08-20T03:36:32ZengMDPI AGPlants2223-77472025-07-011415225510.3390/plants14152255Mitigation of Cadmium and Copper Stress in Lettuce: The Role of Biochar on Metal Uptake, Oxidative Stress, and YieldRiccardo Fedeli0Zhanna Zhatkanbayeva1Rachele Marcelli2Yerlan Zhatkanbayev3Sara Desideri4Stefano Loppi5BioAgry Lab, Department of Life Sciences, University of Siena, 53100 Siena, ItalyLaboratory of Engineering Profile, L.N. Gumilyov Eurasian National University, Satpaev Str., 5, Astana 010008, KazakhstanDepartment of Life Sciences, University of Siena, 53100 Siena, ItalyDepartment of Chemistry and Ecology, K. Kulazhanov Kazakh University of Technology and Business, Astana 010000, KazakhstanDepartment of Life Sciences, University of Siena, 53100 Siena, ItalyBioAgry Lab, Department of Life Sciences, University of Siena, 53100 Siena, ItalyBiochar has emerged as a promising soil amendment for mitigating heavy metal contamination in agricultural systems. This study investigates the effects of biochar on cadmium (Cd) and copper (Cu) uptake, plant growth, oxidative stress, and physiological responses in lettuce (<i>Lactuca sativa</i> L.) plants exposed to different metal concentrations. Results indicate that biochar significantly influenced Cd bioavailability, reducing its accumulation in plant tissues by up to 31.9% and alleviating oxidative stress, with malondialdehyde and proline levels decreasing by up to 51.0% and 60.2%, particularly at higher application rates (5%). Cd-exposed plants treated with biochar exhibited an improved fresh weight (+22.6%), lower malondialdehyde and proline levels, and enhanced the chlorophyll content (+14.9% to 24.1%) compared to untreated plants. The bioaccumulation factor for Cd decreased (up to 31.8%) while the immobilization index (II) increased, confirming the role of biochar in limiting Cd mobility in soil. In contrast, Cu uptake remained consistently low across all treatments, with a significant reduction observed only at higher contamination levels (up to −34.2%). Biochar contributed to Cu immobilization, reflected in increased II values, and enhanced the plant biomass and chlorophyll content under Cu exposure (+15.4% and up to +24.1%, respectively), suggesting a partial alleviation of Cu toxicity. These findings highlight biochar’s potential in heavy metal remediation, particularly for Cd, by reducing bioavailability and improving plant resilience. However, its role in Cu-contaminated soils is mainly through immobilization rather than uptake reduction.https://www.mdpi.com/2223-7747/14/15/2255bioavailabilitycrop plantsheavy metal remediationmetal immobilizationsustainable agriculture
spellingShingle Riccardo Fedeli
Zhanna Zhatkanbayeva
Rachele Marcelli
Yerlan Zhatkanbayev
Sara Desideri
Stefano Loppi
Mitigation of Cadmium and Copper Stress in Lettuce: The Role of Biochar on Metal Uptake, Oxidative Stress, and Yield
Plants
bioavailability
crop plants
heavy metal remediation
metal immobilization
sustainable agriculture
title Mitigation of Cadmium and Copper Stress in Lettuce: The Role of Biochar on Metal Uptake, Oxidative Stress, and Yield
title_full Mitigation of Cadmium and Copper Stress in Lettuce: The Role of Biochar on Metal Uptake, Oxidative Stress, and Yield
title_fullStr Mitigation of Cadmium and Copper Stress in Lettuce: The Role of Biochar on Metal Uptake, Oxidative Stress, and Yield
title_full_unstemmed Mitigation of Cadmium and Copper Stress in Lettuce: The Role of Biochar on Metal Uptake, Oxidative Stress, and Yield
title_short Mitigation of Cadmium and Copper Stress in Lettuce: The Role of Biochar on Metal Uptake, Oxidative Stress, and Yield
title_sort mitigation of cadmium and copper stress in lettuce the role of biochar on metal uptake oxidative stress and yield
topic bioavailability
crop plants
heavy metal remediation
metal immobilization
sustainable agriculture
url https://www.mdpi.com/2223-7747/14/15/2255
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