School of Chemical Engineering, Yeungnam University, Gyeongsan, Republic of Korea.
Department of Botany, Jamia Hamdard University, New Delhi, 110062, India.
Chemosphere. 2022 Aug;300:134555. doi: 10.1016/j.chemosphere.2022.134555. Epub 2022 Apr 8.
The release and accumulation of metal-oxide nanoparticles in soils have threatened terrestrial plants. However, limited knowledge is available on the accumulation of nano-AlO (22 nm), bulk-AlO (167 nm), and Al by maize plants and the subsequent impact on its physiology and growth in agar (0.7% w/v), hydroponic (1X), and soil. Maize plants were cultivated with 0.05-2 mg g or ml of three Al types and their biological attributes, oxidative status, Al bioaccumulation, and translocation were measured. The ICP-MS results revealed a dose-dependent increase (P ≤ 0.05 or ≤0.01) in Al content in maize tissues following nano-AlO and Al exposure, however, plants exposed to bulk-AlO showed no significant uptake of Al. Atomic mapping by EDX during SEM analysis and TEM revealed varied distributions of nano-AlO from roots to aerial parts and intracellular transportation. Al deposition in tissues followed the order: Al > nano-AlO > bulk-AlO and therefore, a similar trend of toxicity was observed for seed germination, the emergence of plant organs, length, biomass accumulation, total chlorophyll, phosphorus content, and total soluble protein. Oxidative stress was profoundly induced dose-dependently and was highest at 2 mg ml or g of Al and nano-AlO when superoxide radical formation, proline induction, activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (GPX), and glutathione reductase (GR) and membrane lipid peroxidation were measured. Aluminum toxicity was found higher in hydroponically grown maize compared to soil-grown maize. Forty days exposure in soil showed greater inhibition of maize growth compared to 20 days exposure. This study is significant in understanding the maize response to different Al types in soil and soil-free media.
金属氧化物纳米粒子在土壤中的释放和积累对陆地植物造成了威胁。然而，关于玉米植物对纳米 AlO（22nm）、体相 AlO（167nm）和 Al 的积累及其对其在琼脂（0.7%w/v）、水培（1X）和土壤中的生理和生长的后续影响的知识有限。用 0.05-2mg/g 或 ml 的三种 Al 类型培养玉米植物，并测量其生物特性、氧化状态、Al 生物积累和转运。ICP-MS 结果显示，纳米 AlO 和 Al 暴露后，玉米组织中 Al 含量呈剂量依赖性增加（P≤0.05 或≤0.01），而暴露于体相 AlO 的植物对 Al 的吸收没有显著增加。SEM 分析和 TEM 中的 EDX 原子映射显示，纳米 AlO 从根部到地上部分和细胞内运输的分布不同。组织中 Al 的沉积顺序为：Al＞纳米 AlO＞体相 AlO，因此，种子萌发、植物器官出现、长度、生物量积累、总叶绿素、磷含量和总可溶性蛋白的毒性观察到类似的趋势。氧化应激被强烈地诱导，呈剂量依赖性，在 2mg/ml 或 g 的 Al 和纳米 AlO 时最高，此时超氧自由基形成、脯氨酸诱导、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（GPX）和谷胱甘肽还原酶（GR）的活性以及膜脂质过氧化作用最高。与在水培中生长的玉米相比，在土壤中生长的玉米受到更高的 Al 毒性。与 20 天暴露相比，在土壤中暴露 40 天对玉米生长的抑制作用更大。这项研究对于理解玉米对土壤和无土介质中不同 Al 类型的反应具有重要意义。
