Physiological and Biochemical Responses of Satureja bachtiarica Bunge to Cadmium and Lead Toxicity

Articles in Press

Document Type : Original Article

Authors
Ibtihal Ibtihal Khadhim Azra Al-Zobaidi 1
Sajjad Sedaghat 2
Mohammad Jabbari-oranj 3
Yaghoub Heydarzadeh 4
mohamad norani 2
1 University of Al Qadisiyah, Diwaniyah, Qadisiyah, Iraq.
2 Department of Horticultural Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
3 Department of Agronomy and Plant Breeding, Faculty of Agricultural Sciences and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran.
4 University of Tabriz, Tabriz, Islamic Republic of Iran.
Abstract
Heavy metal contamination in agricultural soils threatens crop productivity and medicinal plant safety. This study evaluated the physiological performance, osmoprotective adjustments, antioxidant machinery, and metal partitioning in Satureja bachtiarica Bunge exposed to varying cadmium (Cd: 0–10 mg L⁻¹) and lead (Pb: 0–40 mg L⁻¹) concentrations. Elevated metal levels caused dose-dependent growth impairments; maximal exposure (10 mg L⁻¹ Cd and 40 mg L⁻¹ Pb) reduced stem dry weight by 48.0% and 46.5%, and root dry weight by 59.0% for both metals, respectively. Concurrently, photosynthetic pigments, including chlorophyll a and b, declined significantly under extreme toxicity. To mitigate stress, S. bachtiarica activated robust biochemical defenses. Free proline accumulated predominantly in roots, increasing ~4.0-fold under Cd and 4.3-fold under Pb. Soluble/reducing carbohydrate pools expanded, and shoot ascorbic acid nearly doubled (~94% increase) under maximum Cd stress. Enzymatic defense was also stimulated, with foliar catalase (CAT) and peroxidase (POD) activities significantly upregulated. Crucially, over 90% of absorbed Cd and Pb was compartmentalized in root tissues (up to 98% and 97%, respectively). While the bioaccumulation factor (BF) remained below 0.43, the translocation factor (TF) declined markedly with increasing toxicity (Cd: 0.125 to 0.021; Pb: 0.117 to 0.025; 𝑇𝐹≪1), preventing toxic ion transport to shoots. These findings demonstrate that S. bachtiarica combines strong antioxidant/osmoprotective competence with root-mediated metal exclusion, highlighting its potential as an effective phytostabilizer in Cd- and Pb-contaminated soils.
Keywords
Antioxidant enzymes
Biochemical responses
Growth medium
Heavy metal contamination
Satureja bachtiarica.
Subjects
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Available Online from 16 September 2026