Heavy Metal-Induced Variability in Leaf Nutrient Uptake and Photosynthetic Traits of Avocado (Persea americana) in Mediterranean Soils: A Multivariate and Probabilistic Modeling of Soil-to-Plant Transfer Risks

Heavy Metal-Induced Variability in Leaf Nutrient Uptake and Photosynthetic Traits of Avocado (Persea americana) in Mediterranean Soils: A Multivariate and Probabilistic Modeling of Soil-to-Plant Transfer Risks | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Heavy Metal-Induced Variability in Leaf Nutrient Uptake and Photosynthetic Traits of Avocado (Persea americana) in Mediterranean Soils: A Multivariate and Probabilistic Modeling of Soil-to-Plant Transfer Risks HATIM SANAD, Rachid Moussadek, Abdelmjid Zouahri, Majda Oueld Lhaj, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7993063/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Aims Soil contamination by heavy metals poses a serious threat to crop productivity, food safety, and ecosystem health, particularly in intensively cultivated regions. This study aimed to evaluate the impact of soil heavy metal (HM) contamination on nutrient uptake, photosynthetic performance, and bioaccumulation potential in Persea americana (avocado) orchards across the Mnasra region (Morocco). Methods Twenty representative sites were sampled, each comprising soil and mature avocado leaf tissues. Soil physicochemical properties and HM concentrations (Cd, Pb, Ni, Zn) were analyzed, while leaf samples were assessed for macronutrients (NPK, Ca, Mg), micronutrients (Fe, Mn, Zn, Cu, B), photosynthetic traits (SPAD index, chlorophyll a/b), and metal accumulation. Bioaccumulation Factors (BAFs) were calculated, and data were analyzed using multivariate techniques including Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), Linear Discriminant Analysis (LDA), Partial Least Squares Regression (PLSR), and Monte Carlo Simulation. Results Results revealed wide intra-specific variability across orchards. Leaf Cd and Pb concentrations reached 0.92 and 3.54 mg/kg DW, respectively, with BAF values > 1 in multiple sites. PLSR demonstrated strong predictive power for leaf Cd (R² = 0.789) and Pb (R² = 0.772) from soil data. Monte Carlo simulations identified probabilistic exceedance of FAO/WHO thresholds for Cd and Pb in 15–25% of modeled cases. PCA and HCA distinguished five orchard clusters based on combined soil–leaf profiles. Conclusion This integrative approach confirms that soil metal contamination significantly alters avocado physiology, with site-specific patterns. The study advocates targeted soil monitoring and tailored remediation to support sustainable orchard management in vulnerable regions. Agronomy Heavy Metal Contamination Avocado (Persea americana) Leaf Nutrient Uptake Photosynthetic Performance Multivariate Statistical Analysis (MSA) Monte Carlo Simulation Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7993063","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":537739065,"identity":"8865f2a8-baa3-4725-8be6-681e093d42b4","order_by":0,"name":"HATIM SANAD","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA90lEQVRIiWNgGAWjYBACgwMMDAegbMMHHyqAFDNzAwEtzHAtxoYzzoC0MBLWAgNm0rxtIJqQluPnDx66wVAnb85+eJs077zaaP52oJYfFdtwarE/k8xwOIfhsOHOnrRiy7nbjufOOMzYwNhz5jYeh4G1HGDccCDH8MbbbcdyG4BamBnb8Gg5/xikpc5+w/k3BhK8c47lzieo5QbYFubEDTdyjCR5G2pyNxDW8tjgcI7B4eQNN54VG844diB3I1DLQbx+OZ/4+HNORZ3thvPJGx98qKnLnXf+8MEHPypwa4FqhLMOg8kDBNSjgDpSFI+CUTAKRsEIAQCXqmbAcElcZQAAAABJRU5ErkJggg==","orcid":"","institution":"Laboratory of Process Engineering and Environment, Faculty of Science and Technology Mohammedia, University Hassan II of Casablanca, Mohammedia 28806, Morocco","correspondingAuthor":true,"prefix":"","firstName":"HATIM","middleName":"","lastName":"SANAD","suffix":""},{"id":537739066,"identity":"c511298f-2427-4452-a330-9cdf39ea3179","order_by":1,"name":"Rachid Moussadek","email":"","orcid":"","institution":"International Center for Agricultural Research in the Dry Areas (ICARDA), Rabat 10100, Morocco","correspondingAuthor":false,"prefix":"","firstName":"Rachid","middleName":"","lastName":"Moussadek","suffix":""},{"id":537739067,"identity":"00b57cec-6fd5-405e-86e4-804f42c0ab70","order_by":2,"name":"Abdelmjid Zouahri","email":"","orcid":"","institution":"Research Unit on Environment and Conservation of Natural Resources, Regional Center of Rabat, National Institute of Agricultural Research, AV. 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Probabilistic Modeling of Soil-to-Plant Transfer Risks\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University of Hassan II Casablanca","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Heavy Metal Contamination, Avocado (Persea americana), Leaf Nutrient Uptake, Photosynthetic Performance, Multivariate Statistical Analysis (MSA), Monte Carlo Simulation","lastPublishedDoi":"10.21203/rs.3.rs-7993063/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7993063/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eAims\u003c/h2\u003e\u003cp\u003eSoil contamination by heavy metals poses a serious threat to crop productivity, food safety, and ecosystem health, particularly in intensively cultivated regions. This study aimed to evaluate the impact of soil heavy metal (HM) contamination on nutrient uptake, photosynthetic performance, and bioaccumulation potential in \u003cem\u003ePersea americana\u003c/em\u003e (avocado) orchards across the Mnasra region (Morocco).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eTwenty representative sites were sampled, each comprising soil and mature avocado leaf tissues. Soil physicochemical properties and HM concentrations (Cd, Pb, Ni, Zn) were analyzed, while leaf samples were assessed for macronutrients (NPK, Ca, Mg), micronutrients (Fe, Mn, Zn, Cu, B), photosynthetic traits (SPAD index, chlorophyll a/b), and metal accumulation. Bioaccumulation Factors (BAFs) were calculated, and data were analyzed using multivariate techniques including Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), Linear Discriminant Analysis (LDA), Partial Least Squares Regression (PLSR), and Monte Carlo Simulation.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eResults revealed wide intra-specific variability across orchards. Leaf Cd and Pb concentrations reached 0.92 and 3.54 mg/kg DW, respectively, with BAF values\u0026thinsp;\u0026gt;\u0026thinsp;1 in multiple sites. PLSR demonstrated strong predictive power for leaf Cd (R\u0026sup2; = 0.789) and Pb (R\u0026sup2; = 0.772) from soil data. Monte Carlo simulations identified probabilistic exceedance of FAO/WHO thresholds for Cd and Pb in 15\u0026ndash;25% of modeled cases. PCA and HCA distinguished five orchard clusters based on combined soil\u0026ndash;leaf profiles.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThis integrative approach confirms that soil metal contamination significantly alters avocado physiology, with site-specific patterns. The study advocates targeted soil monitoring and tailored remediation to support sustainable orchard management in vulnerable regions.\u003c/p\u003e","manuscriptTitle":"Heavy Metal-Induced Variability in Leaf Nutrient Uptake and Photosynthetic Traits of Avocado (Persea americana) in Mediterranean Soils: A Multivariate and Probabilistic Modeling of Soil-to-Plant Transfer Risks","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-07 14:00:09","doi":"10.21203/rs.3.rs-7993063/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"67a24f46-6077-4ec0-85c2-c11ae6bb5124","owner":[],"postedDate":"November 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":57188539,"name":"Agronomy"}],"tags":[],"updatedAt":"2025-11-07T14:00:09+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-07 14:00:09","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7993063","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7993063","identity":"rs-7993063","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}