Centre for Mined Land Rehabilitation, Sustainable Minerals Institute, The University of Queensland, Brisbane, QLD, 4072, Australia.
Centre for Mined Land Rehabilitation, Sustainable Minerals Institute, The University of Queensland, Brisbane, QLD, 4072, Australia.
Plant Physiol Biochem. 2021 Jul;164:147-159. doi: 10.1016/j.plaphy.2021.04.025. Epub 2021 Apr 28.
The terrestrial fern Pityrogramma calomelanos, a cosmopolitan tropical species, is one of the strongest known arsenic (As) hyperaccumulator plants. This study aimed to determine whether P. calomelanos preferentially forages for arsenite (As) or arsenate (As) in As-contaminated soils, and whether a positive root response to As enhances accumulation in P. calomelanos. Therefore, an experiment using rhizoboxes divided in two halves were constructed with a control soil (C) and As or As dosed soil at either 50 and 100 μg g As. Micro-X-ray Fluorescence elemental mapping (μXRF) was employed to analyze the distribution of As in roots and fronds, and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) was used to determine As distribution in the reproductive tissues of P. calomelanos. The results showed that Pityrogramma roots do not specifically forage for As-contaminated soil; the area based on pixel counts was similar across all the treatments with no statistical differences. However, frond biomass was slightly higher in the treatments C ǀ As and C ǀ As, and the highest accumulation of As in fronds was in the As ǀ As (100 μg g) treatment, with 3418 and 2370 μg g in old and young fronds respectively. Arsenic cycling across the roots was observed by the μXRF mapping; in C ǀ As (100) the As was higher and evenly distributed in both sections, whilst in C ǀ As (50), the As was higher in the As side. The μXRF mapping showed a broader As distribution in older fronds, where As was highest in the rachis and extended into the pinnule through the midrib. Pityrogramma calomelanos does not specifically root forage for As-enriched zones in the soil and grows healthily without signs of toxicity at lower (50 μg g) and higher (100 μg g) concentrations of As and As in the soil.
陆生蕨类植物金毛狗是一种分布广泛的热带砷超积累物种，是已知最强的砷（As）超积累植物之一。本研究旨在确定金毛狗是否优先在砷污染土壤中摄取亚砷酸盐（As）或砷酸盐（As），以及根对 As 的正向响应是否会增强其在金毛狗中的积累。因此，构建了一个使用 rhizobox 并将其分为两半的实验，一半是对照土壤（C），另一半是砷或砷处理的土壤，浓度分别为 50 和 100μg g As。微 X 射线荧光元素成像（μXRF）被用于分析 As 在根和羽片的分布，扫描电子显微镜与能量色散光谱（SEM-EDS）用于确定 As 在金毛狗生殖组织中的分布。结果表明，金毛狗的根并不专门在受污染的土壤中觅食；基于像素计数的面积在所有处理中相似，没有统计学差异。然而，在 C ǀ As 和 C ǀ As 处理中，羽片生物量略高，而在 As ǀ As（100μg g）处理中，羽片的 As 积累量最高，老羽片和幼羽片分别为 3418 和 2370μg g。通过 μXRF 图谱观察到根中的 As 循环；在 C ǀ As（100）中，As 在两个部分中都更高且分布均匀，而在 C ǀ As（50）中，As 在 As 侧更高。μXRF 图谱显示，在较老的羽片中，As 的分布更广，其中在中脉处的羽轴中含量最高，并通过中脉延伸到小羽片。金毛狗不会专门在土壤中摄取富砷区，并且在较低（50μg g）和较高（100μg g）的 As 和 As 浓度下，生长健康，没有毒性迹象。
