Institute of Agricultural Biology and Biotechnology - National Research Council (IBBA-CNR), Via Salaria Km 29.300, 00015 Monterotondo Scalo, Rome, Italy.
Department of Sciences, University of Roma Tre, Viale G. Marconi 446, 00146 Rome, Italy.
Aquat Toxicol. 2022 Sep;250:106260. doi: 10.1016/j.aquatox.2022.106260. Epub 2022 Aug 1.
Duckweeds are aquatic plants often used in phytotoxic studies for their small size, simple structure, rapid growth, high sensitivity to pollutants and facility of maintaining under laboratory conditions. In this paper, induced phytotoxic effects were investigated in Lemna minor and Lemna minuta after exposition to silver nitrate (AgNO) and silver nanoparticles stabilized with sodium citrate and L-Cysteine (AgNPs-Cit-L-Cys) at different concentrations (0, 20 and 50 mg/L) and times (7 and 14 days). Lemna species responses were evaluated analyzing plant growth (mat thickness, fresh and dry biomass, relative growth rate - RGR) and physiological parameters (chlorophyll - Chl, malondialdehyde - MDA, ascorbate peroxidase - APX and catalase - CAT). Ag content was measured in the fronds of the two Lemna species by inductively coupled plasma optical emission spectrometry. AgNO and AgNPs-Cit-L-CYs produced phytotoxic effects on both duckweed species (plant growth and Chl reduction, MDA increase) that enhanced in response to increasing concentrations and exposure times. AgNPs-Cit-L-Cys caused much less alteration in the plants compared to AgNO suggesting that the presence of bifunctionalized AgNPs-Cit-L-Cys have a reduced phytotoxic effect as compared to Ag released in water. Based on the physiological performance, L. minuta plants showed a large growth reduction and higher levels of chlorosis and stress in respect to L. minor plants, probably due to greater Ag ions accumulation in the fronds. Albeit with some differences, both Lemna species were able to uptake Ag ions from the aqueous medium, especially over a period of 14 days, and could be considered adapt as phytoremediation agents for decontaminating silver ion-polluted water.
浮萍是水生植物，由于其体积小、结构简单、生长迅速、对污染物高度敏感且易于在实验室条件下维持，因此常被用于植物毒性研究。在本文中，研究了硝酸银（AgNO）和柠檬酸稳定的银纳米颗粒与 L-半胱氨酸（AgNPs-Cit-L-Cys）在不同浓度（0、20 和 50mg/L）和时间（7 和 14 天）暴露后对浮萍属（Lemna minor 和 Lemna minuta）的诱导植物毒性效应。通过分析植物生长（垫厚度、鲜重和干重、相对生长率-RGR）和生理参数（叶绿素-Chl、丙二醛-MDA、抗坏血酸过氧化物酶-APX 和过氧化氢酶-CAT）来评估浮萍物种的反应。通过电感耦合等离子体发射光谱法测量两种浮萍属植物叶片中的 Ag 含量。AgNO 和 AgNPs-Cit-L-Cys 对两种浮萍都产生了植物毒性效应（植物生长和 Chl 减少，MDA 增加），且随着浓度和暴露时间的增加而增强。与 AgNO 相比，AgNPs-Cit-L-Cys 对植物的影响要小得多，这表明双官能化的 AgNPs-Cit-L-Cys 与水中释放的 Ag 相比，具有较低的植物毒性效应。基于生理表现，L. minuta 植物的生长减少幅度较大，叶片出现黄化和胁迫程度较高，而 L. minor 植物则较小，这可能是由于叶片中 Ag 离子积累较多。尽管存在一些差异，但两种浮萍都能够从水介质中吸收 Ag 离子，尤其是在 14 天的时间内，可被认为是一种适应性强的植物修复剂，可用于净化含银离子污染的水。
