College of Agriculture, Guizhou University, Guiyang, 550025, China.
Key Laboratory of Karst Geological Resources and Environment of Ministry of Education, Guizhou University, Guiyang, 550025, China.
Sci Rep. 2024 Aug 13;14(1):18833. doi: 10.1038/s41598-024-69652-5.
Coix lacryma-jobi L. is a traditional medicinal plant in east Asia and is an important crop in Guizhou province, southwest China, where there are elevated levels of soil mercury and arsenic (As). Exposure to multiple potentially toxic elements (PTEs) may affect plant accumulation of metal(loid)s and food safety in regions with high geological metal concentrations. Field experiments were conducted to study the effects of PTEs on metal(loid) accumulation and physiological response of C. lacryma in different plant parts at three pollution levels. Total root length, number of root tips, number of branches, and number of root crosses increased with increasing pollution level, with increases in highly polluted areas of 44.2, 57.0, 79.6, and 97.2%, respectively, compared to lightly polluted areas. Under multi-element stress the activity of C. lacryma antioxidant oxidase showed an increase at low and medium PTE concentrations and inhibition at high concentrations. The As contents were all below the maximum limit of cereal food contaminants in China (GB 2762-2022, As < 0.5 mg kg). The stems had high Tl bioconcentration factors but the translocation factors from stem to grain were very low, indicating that the stems may be a key plant part restricting Tl transport to the grains. C. lacryma increased root retention and reduced the transport effect, thus reducing metal accumulation in the grains. C. lacryma adapted to PTE stress through root remodeling and enhanced antioxidant enzyme activities.
薏苡是东亚地区的传统药用植物，也是中国西南部贵州省的重要作物，该地区土壤汞和砷（As）含量较高。暴露于多种潜在有毒元素（PTEs）可能会影响高地质金属浓度地区植物对金属（类）的积累和食品安全。本研究通过田间试验，研究了 PTEs 在三种污染水平下对薏苡不同部位金属（类）积累和生理响应的影响。总根长、根尖端数量、枝数和根交叉数随着污染水平的增加而增加，与轻度污染区相比，高污染区分别增加了 44.2%、57.0%、79.6%和 97.2%。在多元素胁迫下，薏苡抗氧化氧化酶的活性在低浓度和中浓度 PTE 下增加，而在高浓度下抑制。As 含量均低于中国谷物食品污染物最大限量（GB 2762-2022，As<0.5mgkg）。茎具有较高的 Tl 生物浓缩系数，但从茎到谷物的迁移系数非常低，表明茎可能是限制 Tl 向谷物运输的关键植物部位。薏苡通过根系改造和增强抗氧化酶活性来增加根保留和减少运输效应，从而减少谷物中的金属积累。薏苡通过根系重塑和增强抗氧化酶活性来适应 PTE 胁迫。
