Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen, 361102, China; Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China.
Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen, 361102, China.
Chemosphere. 2019 Jul;226:413-420. doi: 10.1016/j.chemosphere.2019.03.172. Epub 2019 Mar 27.
Cd has high activity and bioavailability and is a poisonous element to plants. As a critical ecosysterm, mangroves are subjected to serious Cd pollution. In this research, the hypothesis was presented that improving Fe bioavailability would alleviate Cd phytotoxicity to Avicennia marina (Forsk.) Vierh. To test this, we examined the effect of four exogenous Fe and three Cd concentrations on A. marina. The results showed that a significant positive correlation excited between moderate exogenous Fe concentration and Cd tolerance of A. marina. Moderate exogenous Fe concentration directly or indirectly promoted the formation of Fe plaque, which immobilised more Cd on the root surface and decreased Cd absorption in roots. Furthermore, an exogenous Fe application increased plant biomass and Fe accumulation in A. marina tissues. This improved the competition between Fe and Cd within the plants. Therefore, an Fe application facilitated a decrease in Cd toxicity within A. marina. Simultaneously, a moderate Fe concentration caused an increase in low-molecular-weight organic acid (LMWOA) secretion from the roots. Meanwhile, Cd can be chelated/complexed by LMWOAs. It also played a crucial role in Cd detoxification in A. marina. In conclusion, Fe application accelerated the growth and enhanced Cd tolerance of A. marina. Therefore, improving Fe bioavailability will protect mangroves from Cd contamination.
镉具有高活性和生物利用度，对植物是一种有毒元素。红树林作为一个关键的生态系统，受到严重的镉污染。本研究提出了这样一个假设，即提高铁的生物利用度将减轻镉对海桑（Forsk.） Vierh.的植物毒性。为了验证这一点，我们研究了四种外源铁和三种镉浓度对海桑的影响。结果表明，适量的外源铁浓度与海桑对镉的耐受性之间存在显著的正相关关系。适量的外源铁浓度直接或间接地促进了铁斑的形成，从而使更多的镉固定在根表面，并减少了根对镉的吸收。此外，外源铁的应用增加了海桑组织中的生物量和铁积累。这改善了植物体内铁和镉之间的竞争。因此，铁的应用有助于降低海桑体内的镉毒性。同时，适量的铁浓度会导致根部分泌更多的低分子量有机酸（LMWOA）。同时，镉可以与 LMWOAs 螯合/络合。它在海桑的镉解毒中也起着至关重要的作用。总之，铁的应用促进了海桑的生长，增强了其对镉的耐受性。因此，提高铁的生物利用度将保护红树林免受镉污染。
