Department of Chemical and Geological Science, University of Cagliari, Cagliari, Italy.
Department of Sciences, University of Roma Tre, Rome, Italy.
Sci Total Environ. 2023 Apr 20;870:161931. doi: 10.1016/j.scitotenv.2023.161931. Epub 2023 Jan 31.
Juncus acutus has been proposed as a suitable species for the design of phytoremediation plans. This research aimed to investigate the role played by rhizosphere minerals and water composition on Zn transformations and dynamics in the rhizosphere-plant system of J. acutus exposed to different Zn sources. Rhizobox experiments were conducted using three different growing substrates (Zn from 137 to 20,400 mg/kg), and two irrigation lines (Zn 0.05 and 180 mg/l). The plant growth was affected by the substrate type, whereas the Zn content in the water did not significantly influence the plant height for a specific substrate. J. acutus accumulated Zn mainly in roots (up to 10,000 mg/kg dw); the metal supply by the water led to variable increases in the total Zn concentration in the vegetal organs, and different Zn distributions both controlled by the rhizosphere mineral composition. Different Zn complexation mechanisms were observed, mainly driven by cysteine and citrate compounds, whose amount increased linearly with Zn content in water, but differently for each of the investigated systems. Our study contributes to gain a more complete picture of the Zn pathway in the rhizosphere-plant system of J. acutus. We demonstrated that this vegetal species is not only capable of developing site-specific tolerance mechanisms, but it is also capable to differently modulate Zn transformation when Zn is additionally supplied by watering. These findings are necessary for predicting the fate of Zn during phytoremediation of sites characterized by specific mineralogical properties and subject to water chemical variations.
菰被提议作为设计植物修复计划的合适物种。本研究旨在调查根际矿物质和水组成对暴露于不同锌源的菰根际-植物系统中锌转化和动态的影响。使用三种不同的生长基质（锌含量为 137 至 20400mg/kg）和两条灌溉线（锌 0.05 和 180mg/l）进行根盒实验。基质类型影响植物生长，而水的锌含量对特定基质的植物高度没有显著影响。菰主要在根部积累锌（高达 10000mg/kg 干重）；水供应的金属导致植物器官中总锌浓度的可变增加，并且受根际矿物质组成控制的不同锌分布。观察到不同的锌络合机制，主要由半胱氨酸和柠檬酸化合物驱动，其含量随水中锌含量线性增加，但对于每个研究系统都不同。本研究有助于更全面地了解菰根际-植物系统中锌的途径。我们证明，这种植物不仅能够发展特定地点的耐受机制，而且当通过浇水额外提供锌时，它还能够不同地调节锌的转化。这些发现对于预测在具有特定矿物性质和受水化学变化影响的地点进行植物修复过程中锌的命运是必要的。
