Endorhizal fungal symbiosis in lycophytes and metal(loid)-accumulating ferns growing naturally in mine wastes in Mexico

Ferns and lycophytes are pioneer plants that can be useful for revegetation. Their natural distribution and interaction with soil fungal endophytes can increase plant fitness but have received little attention. This study aimed to identify these plant species in mine wastes, and determine colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE). The pseudo-total and diethylenetriamine pentaacetic acid (DTPA)-extractable rhizosphere concentrations of As, Cu, Cd, Pb, and Zn, bioavailability index (BI), and bioconcentration factor (BCF) were analyzed. Six ferns and one lycophyte were identified. Arsenic and metal concentrations were high, which were plant and site-dependent. All species showed hyperaccumulation of As in fronds, especially <i>Argyrochosma formosa</i> (2,883) and <i>Notholaena affinis</i> (2,160) had the highest concentrations (mg kg⁻¹). All plants were colonized by AMF (3%−24%) and DSE (2%−33%). <i>Astrolepis sinuata</i> and <i>Myriopteris notholaenoides</i> had the maximum colonization by AMF and <i>A. formosa</i> by DSE. This study identifies for the first time five ferns and one lycophyte species on mine wastes, their As hyperaccumulation capacity and the simultaneous fungal colonization by AMF and DSE. These are relevant plant traits for phytoremediation. However, fungal identification and the role colonization by AMF and DSE requires full analysis. Arsenic accumulator ferns and a lycophytes species naturally established on three polluted sites were found. <i>Astrolepis integerrima, A. sinuata</i>, <i>Myriopteris notholaenoides, Notholaena affinis</i>, <i>N. sulphurea</i>, and the lycophyte <i>Selaginella lepidophylla</i> are for the first time reported in these sites. This is the first evidence of DSE colonization in these plants growing on mine wastes in interaction with AMF-colonization. These plants may be useful in developing phytoremediation alternatives.

蕨类植物（ferns）和石松类植物（lycophytes）是可用于植被恢复的先锋植物。它们的自然分布格局及其与土壤真菌内生菌的互作可提升植物适合度，但相关研究尚未受到足够关注。本研究旨在对矿山尾矿中的该类植物进行物种鉴定，并明确其被丛枝菌根真菌（arbuscular mycorrhizal fungi, AMF）和暗色有隔内生真菌（dark septate endophytes, DSE）定殖的情况。本研究分析了砷（As）、铜（Cu）、镉（Cd）、铅（Pb）及锌（Zn）的伪全量和二乙三胺五乙酸（DTPA）提取态根际浓度，同时测定了生物有效性指数（BI）与生物富集系数（BCF）。共鉴定出6种蕨类植物与1种石松类植物。样地中砷与重金属浓度较高，且其含量因植物种类与采样位点而异。所有供试植物的羽片中均表现出砷超富集特性，其中<i>Argyrochosma formosa</i>（2883 mg·kg⁻¹）与<i>Notholaena affinis</i>（2160 mg·kg⁻¹）的砷富集浓度最高。所有供试植物均被AMF（定殖率3%~24%）与DSE（定殖率2%~33%）定殖。<i>Astrolepis sinuata</i>与<i>Myriopteris notholaenoides</i>的AMF定殖率最高，而<i>A. formosa</i>的DSE定殖率最高。本研究首次在矿山尾矿中鉴定出5种蕨类植物与1种石松类植物，明确了它们的砷超富集能力以及同时被AMF与DSE定殖的特征。上述特性均为可用于植物修复的关键植物性状。但目前仍需对真菌种类鉴定以及AMF与DSE定殖的作用机制开展全面研究。本研究在3个污染位点发现了自然定植的砷富集蕨类植物与1种石松类植物。<i>Astrolepis integerrima</i>、<i>A. sinuata</i>、<i>Myriopteris notholaenoides</i>、<i>Notholaena affinis</i>、<i>N. sulphurea</i>以及石松类植物<i>Selaginella lepidophylla</i>均为首次在该类位点被报道。本研究首次证实了矿山尾矿生境中这些植物同时被DSE与AMF定殖的互作现象。此类植物可为植物修复技术的开发提供潜在候选材料。