Henan Normal University, College of Life Sciences, Xinxiang 453007, China; Research Center for Ecological Management and Protection of the Yellow River Basin, Xinxiang 453007, China.
Henan Normal University, College of Life Sciences, Xinxiang 453007, China.
Ecotoxicol Environ Saf. 2023 Jan 15;250:114484. doi: 10.1016/j.ecoenv.2022.114484. Epub 2023 Jan 4.
Aluminum (Al) is a concentration-dependent toxic metal found in the crust of earth that has no recognized biological use. Nonetheless, the mechanism of Al toxicity to submerged plants remains obscure, especially from a cell/subcellular structure and functional group perspective. Therefore, multiple dosages of Al (0, 0.3, 0.6, 1.2, and 1.5 mg/L) were applied hydroponically to the submerged plant Vallisneria natans in order to determine the accumulation potential of Al at the subcellular level and their ultrastructural toxicity. More severe structural and ultrastructural damage was determined when V. natans exposed to ≥ 0.6 mg/L Al. In 1.2 and 1.5 mg/L Al treatment groups, the total chlorophyll content of leaves significantly reduced 3.342, 3.838 mg/g FW, some leaves even exhibited chlorosis and fragility. Under 0.3 mg/L Al exposure, the middle-age and young leaves were potent phytoexcluders, whereas at 1.5 mg/L Al, a large amount of Al could be transferred from the roots to other parts, among which the aged leaves were the most receptive tissues (7.306 mg/g). Scanning/Transmission electron microscopy analysis displayed the Al-mediated disruption of vascular bundle structure in leaf cells, intercellular space and several vegetative tissues, and demonstrated that Al in vacuole and chloroplast subcellular segregation into electron dense deposition. Al and P accumulation in the roots, stolons and leaves varied significantly among treatments and different tissues (P < 0.05). Fourier transform infrared spectroscopy of plant biomass also indicated possible metabolites (amine, unsaturated hydrocarbon, etc.) of V. natans that may bind Al. Conclusively, results revealed that Al disrupts the cellular structure of leaves and roots or binds to functional groups of biological tissues, thereby affecting plant nutrient uptake and photosynthesis. Findings might have scientific and practical significance for the restoration of submerged vegetation in Al-contaminated lakes.
铝（Al）是地壳中一种浓度依赖性的有毒金属，没有被认为具有生物利用价值。然而，铝对沉水植物的毒性机制仍然不清楚，特别是从细胞/亚细胞结构和功能基团的角度来看。因此，采用水培法向沉水植物苦草（Vallisneria natans）施加了多个剂量的铝（0、0.3、0.6、1.2 和 1.5mg/L），以确定铝在亚细胞水平上的积累潜力及其超微结构毒性。当 V. natans 暴露于≥0.6mg/L Al 时，会出现更严重的结构和超微结构损伤。在 1.2 和 1.5mg/L Al 处理组中，叶片的总叶绿素含量分别显著降低了 3.342、3.838mg/gFW，部分叶片甚至出现黄化和脆弱。在 0.3mg/L Al 暴露下，中叶和幼叶是有效的植物排斥物，而在 1.5mg/L Al 下，大量的 Al 可以从根部转移到其他部位，其中老叶是最易受影响的组织（7.306mg/g）。扫描/透射电子显微镜分析显示，铝介导了叶片细胞、细胞间隙和几种营养组织中维管束结构的破坏，证明了铝在液泡和叶绿体中的亚细胞分离成电子致密沉积物。根、匍匐茎和叶片中 Al 和 P 的积累在处理和不同组织之间差异显著（P<0.05）。植物生物量的傅里叶变换红外光谱也表明，苦草可能存在与 Al 结合的代谢物（胺、不饱和烃等）。总之，结果表明，铝破坏了叶片和根部的细胞结构，或者与生物组织的功能基团结合，从而影响植物对养分的吸收和光合作用。研究结果对受 Al 污染的湖泊中沉水植被的恢复具有科学和实际意义。
