Arsenic toxicity induces a range of metabolic responses in plants, including DNA methylation. The focus of this paper was on the relationship between As-induced stress and plant senescence in the hyperaccumulator Pteris cretica var. Albo-lineata (Pc-Al). We assume difference in physiological parameters and level of DNA methylation in young and old fronds as symptoms of As toxicity. The As accumulation of Pc-Al fronds, grown in pots of haplic chernozem contaminated with 100 mg As kg− 1 for 122 days, decreased with age. Content of As was higher in young than old fronds for variants with 100 mg As kg− 1 (2800 and 2000 mg As kg− 1 dry matter, respectively). The highest As content was determined in old fronds of Pc-Al grown in pots with 250 mg As kg− 1. The increase with age was confirmed for determined nutrients – Cu, Mg, Mn, S and Zn. A significant elevation of all analysed nutrients was showed in old fronds. Arsenic accumulation affected DNA methylation status in fronds, but content of 5-methylcytosine (5mC) decreased only in old fronds of Pc-Al (from 25 to 12%). Determined photosynthetic processes showed a decrease of fluorescence, photosynthetic rate and chlorophylls of As treatments in young and old fronds. Water potential was decreased by As in both fronds. Thinning of the sclerenchymatous inner cortex and a reduction in average tracheid metaxylem in the vascular cylinder was showed in roots of As treatment. Irrespective to fronds age, physiological parameters positively correlated with a 5mC while negatively with direct As toxicity. Opposite results were found for contents of Cu, Mg, Mn, S and Zn. The results of this paper point to changes in the metabolism of the hyperaccumulator plant Pc-Al, upon low and high exposure to As contamination. The significant impact of As on DNA methylation was found in old fronds. Irrespective to fronds age, significant correlations were confirmed for 5mC and As toxicity. Our analysis of the very low water potential values and lignification of cell walls in roots showed that transports of assimilated metabolites and water between roots and fronds were reduced. As was showed by our results, epigenetic changes could affect studied parameters of the As hyperaccumulator plant Pc-Al, especially in old fronds.

中文翻译：

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砷胁迫对砷超富集凤尾蕨中5-甲基胞嘧啶，光合参数和养分含量的影响。线虫

砷中毒会引起植物一系列的代谢反应，包括DNA甲基化。本文的重点是在超级蓄积凤尾蕨中砷诱导的胁迫与植物衰老之间的关系。Albo-lineata（Pc-Al）。我们假设生理参数的差异以及年轻和年老患者的DNA甲基化水平均作为As毒性的症状。Pc-Al叶片的砷积累量在被100 mg As kg-1污染的触角黑钙土中生长122天，随着年龄的增长而降低。对于具有100 mg As kg-1（分别为2800和2000 mg As kg-1干物质）的变体，年轻烟叶中的As含量高于老烟叶。在含有250 mg As kg-1的盆中生长的Pc-Al旧叶中测定出最高的As含量。确定的养分– Cu，Mg，Mn，S和Zn随着年龄的增长而增加。在老叶中，所有分析到的营养素均显着升高。砷的积累影响了叶片中DNA甲基化的状态，但是5-甲基胞嘧啶（5mC）的含量仅在旧的Pc-Al叶片中降低了（从25％降至12％）。确定的光合作用过程表明，在年轻和老叶体中，As处理的荧光，光合速率和叶绿素均下降。在两个叶片中，水势均被As降低。在As处理的根部显示，硬化性内层皮层变薄，血管圆筒中的平均气管异位体减少。与叶龄无关，生理参数与5mC正相关，而与直接As毒性负相关。发现Cu，Mg，Mn，S和Zn的含量相反。本文的结果指出，高和低浓度砷暴露后，高蓄积植物Pc-Al的代谢发生变化。在老叶中发现了砷对DNA甲基化的显着影响。与叶龄无关，证实了5mC和As毒性具有显着相关性。我们对极低的水势值和根部细胞壁木质化的分析表明，减少了根与叶之间同化代谢产物和水的运输。正如我们的结果所示，表观遗传变化可能会影响砷超积累植物Pc-Al的研究参数，尤其是在老叶中。证实5mC和As毒性具有显着相关性。我们对极低的水势值和根部细胞壁木质化的分析表明，减少了根与叶之间同化代谢产物和水的运输。正如我们的结果所示，表观遗传变化可能会影响砷超积累植物Pc-Al的研究参数，尤其是在老叶中。证实5mC和As毒性具有显着相关性。我们对极低的水势值和根部细胞壁木质化的分析表明，减少了根与叶之间同化代谢产物和水的运输。正如我们的结果所示，表观遗传变化可能会影响砷超积累植物Pc-Al的研究参数，尤其是在老叶中。