National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of tobacco Science, Henan Agricultural University, Zhengzhou 450002, China.
National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of tobacco Science, Henan Agricultural University, Zhengzhou 450002, China.
Ecotoxicol Environ Saf. 2023 Sep 15;263:115361. doi: 10.1016/j.ecoenv.2023.115361. Epub 2023 Aug 17.
Cadmium (Cd) removal from soil to reduce Cd accumulation in plants is essential for agroecology, food safety, and human health. Cd enters plants from soil and affects plant growth and development. Hydrogels can easily combine with Cd, thereby altering its bioavailability in soil. However, few studies have evaluated the effects of hydrogel on the complex phytotoxicity caused by Cd uptake in plants and the microbial community structure. Herein, a new poly (acrylic acid)-grafted starch and potassium humate composite (S/K/AA) hydrogel was added to soil to evaluate its impact on tobacco growth and the soil microenvironment. The results indicate that the addition of S/K/AA hydrogel can significantly improve the biomass, chlorophyll (Chl) content, and photosynthetic capacity of tobacco plants during Cd stress conditions, and decrease Cd concentration, probably by affecting Cd absorption through the expression of Cd absorption transporters (e.g., NRAMP5, NRAMP3, and IRT1). Moreover, the application of S/K/AA hydrogel not only reduced the accumulation of reactive oxygen species (ROS), but also reduced the antioxidant activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), suggesting that S/K/AA hydrogel alleviates Cd toxicity via a non-antioxidant pathway. Notably, we further analyzed the effectiveness of the hydrogel on microbial communities in Cd-contaminated soil and found that it increased the Cd-tolerant microbial community (Arthrobacter, Massilia, Streptomyces), enhancing the remediation ability of Cd-contaminated soil and helping tobacco plants to alleviate Cd toxicity. Overall, our study provides primary insights into how S/K/AA hydrogel affects Cd bioavailability and alleviates Cd toxicity in plants.
从土壤中去除镉以减少植物中镉的积累对于农业生态、食品安全和人类健康至关重要。镉从土壤进入植物，影响植物的生长和发育。水凝胶可以很容易地与镉结合，从而改变其在土壤中的生物利用度。然而，很少有研究评估水凝胶对植物吸收镉引起的复杂植物毒性和微生物群落结构的影响。在此，将一种新的聚丙烯酸接枝淀粉和腐植酸钾复合（S/K/AA）水凝胶添加到土壤中，以评估其对烟草生长和土壤微环境的影响。结果表明，在镉胁迫条件下，S/K/AA 水凝胶的添加可以显著提高烟草植株的生物量、叶绿素（Chl）含量和光合作用能力，降低镉浓度，这可能是通过影响镉吸收转运体（如 NRAMP5、NRAMP3 和 IRT1）的表达来实现的。此外，S/K/AA 水凝胶的应用不仅降低了活性氧（ROS）的积累，还降低了过氧化物酶（POD）、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的抗氧化活性，表明 S/K/AA 水凝胶通过非抗氧化途径缓解镉毒性。值得注意的是，我们进一步分析了水凝胶对镉污染土壤中微生物群落的有效性，发现它增加了镉耐受微生物群落（节杆菌属、马塞利亚菌属、链霉菌属），增强了镉污染土壤的修复能力，并帮助烟草植物缓解镉毒性。总的来说，我们的研究提供了初步的见解，即 S/K/AA 水凝胶如何影响镉的生物利用度并缓解植物中的镉毒性。
