BACKGROUND Quinoa (Chenopodium quinoa Willd) is an Andean original pseudocereal with high nutritional value. During quinoa processing, large amounts of saponin-rich husks byproducts are obtained. Quinoa saponins, which are biologically active, could be used for various agriculture purposes. Silver nanoparticles have increasingly attracted attention for the management of crop diseases in agriculture. In this work, silver nanoparticles are synthesized by a sustainable and green method, using quinoa husk saponin extract (QE) to evaluate their potential for application in agriculture as biostimulants. RESULTS Quinoa extract was obtained and characterized by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Sixteen saponin congeners were successfully identified and quantified. The QE obtained was used as a reducing agent for silver ions to synthesize silver nanoparticles (QEAgNPs) under mild conditions. The morphology, particle size, and stability of Ag nanoparticles were investigated by transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-visible), energy-dispersive X-ray (EDS), zeta potential, and Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). Ultraviolet-visible spectroscopy measurements confirmed the formation of silver nanoparticles in the presence of QE, with estimated particle sizes in a range between 5 and 50 nm. According to the zeta potential values, highly stable nanoparticles were formed. The QE and QEAgNPs (200-1000 μg/mL) were also tested in radish seed bioassay to evaluate their phytotoxicity. The seed germination assays revealed that QEAgNPs possessed a phytostimulant effect on radish seeds in a dose-dependent manner, and no phytotoxicity was observed for both QE and QEAgNPs. CONCLUSION Silver nanoparticles obtained by a so-called 'green' method could be considered as good candidates for application in the agricultural sector for seed treatment, or as foliar sprays and plant-growth-promoters. © 2020 Society of Chemical Industry.

中文翻译：

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藜麦皂苷提取物获得的高稳定性银纳米粒子的植物刺激特性

背景藜麦（Chenopodium quinoa Willd）是一种营养价值很高的安第斯原始假谷物。在藜麦加工过程中，会获得大量富含皂苷的果壳副产品。藜麦皂苷具有生物活性，可用于各种农业用途。银纳米粒子在农业作物病害管理方面越来越受到关注。在这项工作中，银纳米粒子通过可持续和绿色的方法合成，使用藜麦壳皂苷提取物 (QE) 来评估其作为生物刺激剂在农业中的应用潜力。结果 藜麦提取物通过液相色谱串联质谱 (LC-MS/MS) 获得并表征。成功鉴定并定量了 16 种皂苷同系物。获得的 QE 用作银离子的还原剂，以在温和条件下合成银纳米粒子 (QEAgNPs)。通过透射电子显微镜 (TEM)、紫外-可见光谱 (UV-visible)、能量色散 X 射线 (EDS)、zeta 电位和傅里叶变换红外光谱研究了 Ag 纳米粒子的形貌、粒径和稳定性。衰减全反射 (FTIR-ATR)。紫外可见光谱测量证实了在 QE 存在下银纳米粒子的形成，估计粒径在 5 到 50 nm 之间。根据zeta电位值，形成了高度稳定的纳米颗粒。QE 和 QEAgNPs (200-1000 μg/mL) 也在萝卜种子生物测定中进行了测试，以评估它们的植物毒性。种子萌发试验表明，QEAgNPs 以剂量依赖性方式对萝卜种子具有植物刺激作用，QE 和 QEAgNPs 均未观察到植物毒性。结论 通过所谓的“绿色”方法获得的银纳米粒子可以被认为是在农业部门进行种子处理或作为叶面喷雾剂和植物生长促进剂应用的良好候选者。© 2020 化学工业协会。