Fan Peidang, Shi Hang, Ling Huaxin, Li Bo, Yang Fumo, Huang Chengtao, Zhang Liuyi
Three Gorges Reservoir Area Environment and Ecology of Chongqing Observation and Research Station, Chongqing Key Laboratory of Water Environment Evolution and Pollution Prevention and Control in Three Gorges Reservoir Area, Chongqing Three Gorges University, Chongqing, China.
College of Carbon Neutrality Future Technology, Sichuan University, Chengdu, China.
Physiol Plant. 2025 Sep-Oct;177(5):e70484. doi: 10.1111/ppl.70484.
Cadmium (Cd) pollution threatens agricultural ecosystems and human health, yet the combined impacts of atmospheric and soil Cd exposure on plant accumulation dynamics remain underexplored. The investigation focuses on the two main Cd uptake routes, soil-root and atmosphere-leaf, in Nicotiana tabacum L., a commercial crop with a notable ability to hyperaccumulate Cd. Controlled experiments were conducted to simulate realistic exposure conditions, providing insights into how these pathways interact and influence Cd accumulation in plants. The key findings revealed that soil was the dominant Cd source (88.29%-92.63%), while atmospheric deposition contributed 3.54%-7.36%, with leaves acting as the primary sink (> 70% of total Cd). Subcellular distribution identified the cell walls (48%-75%) and vacuoles (21%-50%) as critical sequestration sites, mediated by pectin binding and phytochelatin-Cd complexes. Low atmospheric Cd enhanced biomass (10%) and antioxidant activity, whereas combined high stress (AHSH group) suppressed growth (plant height (PH) 18%, root length (RL) 26%) and chlorophyll synthesis (29%), alongside oxidative stress escalation (HO 53%, MDA 147%). Antioxidant enzymes (SOD, CAT, APX) exhibited threshold-dependent responses, being stimulated at low Cd levels but suppressed at high doses, which indicates limits to the detoxification capacity. These results underscore atmospheric Cd as a non-negligible risk factor in tobacco-growing regions, advocating for integrated soil-air monitoring frameworks to safeguard crop safety and ecosystem health.
镉（Cd）污染威胁着农业生态系统和人类健康，然而大气和土壤中镉暴露对植物积累动态的综合影响仍未得到充分研究。本研究聚焦于烟草（Nicotiana tabacum L.）吸收镉的两条主要途径，即土壤-根系途径和大气-叶片途径。烟草是一种具有显著镉超积累能力的经济作物。通过控制实验模拟实际暴露条件，以深入了解这些途径如何相互作用并影响植物体内的镉积累。主要研究结果表明，土壤是镉的主要来源（88.29%-92.63%），而大气沉降贡献了3.54%-7.36%，叶片是主要的镉蓄积部位（占总镉的>70%）。亚细胞分布研究表明，细胞壁（48%-75%）和液泡（21%-50%）是关键的镉螯合位点，这一过程由果胶结合和植物螯合素-Cd复合物介导。低浓度大气镉可促进生物量增加（10%）和抗氧化活性，而高浓度复合胁迫（AHSH组）则抑制生长（株高（PH）降低18%，根长（RL）降低26%）和叶绿素合成（降低29%），同时氧化应激加剧（过氧化氢（HO）增加53%，丙二醛（MDA）增加147%）。抗氧化酶（超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX））表现出阈值依赖性反应，在低镉水平下被激活，但在高剂量下受到抑制，这表明植物的解毒能力存在限度。这些结果强调了大气镉在烟草种植区是一个不可忽视的风险因素，倡导建立土壤-大气综合监测框架以保障作物安全和生态系统健康。
