Laboratory of Inorganic Chemistry, Department of Chemistry, Aristotle University of Thessaloniki , 54124 Thessaloniki, Greece.
Department of Botany, Aristotle University of Thessaloniki , 54124 Thessaloniki, Greece.
ACS Appl Mater Interfaces. 2018 Feb 7;10(5):4450-4461. doi: 10.1021/acsami.7b17017. Epub 2018 Jan 23.
Inorganic nanoparticles (NPs) have been proposed as alternative fertilizers to suppress plant disease and increase crop yield. However, phytotoxicity of NPs remains a key factor for their massive employment in agricultural applications. In order to investigate new effective, nonphytotoxic, and inexpensive fungicides, in the present study CuZn bimetallic nanoparticles (BNPs) have been synthesized as antifungals, while assessment of photosystem II (PSII) efficiency by chlorophyll fluorescence imaging analysis is utilized as an effective and noninvasive phytotoxicity evaluation method. Thus, biocompatible coated, nonoxide contaminated CuZn BNPs of 20 nm crystallite size and 250 nm hydrodynamic diameter have been prepared by a microwave-assisted synthesis. BNPs' antifungal activity against Saccharomyces cerevisiae was found to be enhanced compared to monometallic Cu NPs. Reactive oxygen species (ROS) formation and photosystem II (PSII) functionality at low light (LL) and high light (HL) intensity were determined on tomato plants sprayed with 15 and 30 mg L of BNPs for the evaluation of their phytotoxicity. Tomato leaves sprayed with 15 mg L of BNPs displayed no significant difference in PSII functionality at LL, while exposure to 30 mg L of BNPs for up to 90 min resulted in a reduced plastoquinone (PQ) pool that gave rise to HO accumulation, initiating signaling networks and regulating acclimation responses. After 3 h of exposure to 30 mg L of BNPs, PSII functionality at LL was similar to control, indicating nonphytotoxic effects. Meanwhile, exposure of tomato leaves either enhanced (15 mg L) or did not have any significant effect (30 mg L) on PSII functionality at HL, attributed to the absence of semiconducting oxide phases and photochemical toxicity-reducing modifications. The use of chlorophyll fluorescence imaging analysis is recommended as a tool to monitor NPs behavior on plants.
无机纳米粒子（NPs）已被提议作为替代肥料来抑制植物病害和提高作物产量。然而，NPs 的植物毒性仍然是其在农业应用中大规模使用的关键因素。为了研究新的有效、非植物毒性和廉价的杀菌剂，本研究合成了铜锌双金属纳米粒子（BNPs）作为杀菌剂，同时利用叶绿素荧光成像分析评估光系统 II（PSII）效率，作为一种有效且非侵入性的植物毒性评估方法。因此，通过微波辅助合成制备了具有 20nm 晶粒度和 250nm 水动力直径的生物相容性包覆、无氧化物污染的 CuZn BNPs。与单金属 Cu NPs 相比，BNPs 对酿酒酵母的抗真菌活性增强。在低光（LL）和高光（HL）强度下，通过向番茄植株喷洒 15 和 30mg/L 的 BNPs 来确定活性氧（ROS）的形成和光系统 II（PSII）功能，以评估其植物毒性。向番茄叶片喷洒 15mg/L 的 BNPs 时，在 LL 下 PSII 功能没有明显差异，而暴露于 30mg/L 的 BNPs 长达 90 分钟会导致质体醌（PQ）库减少，从而导致 HO 积累，引发信号网络并调节适应反应。暴露于 30mg/L 的 BNPs 3 小时后，在 LL 下 PSII 功能与对照相似，表明无植物毒性作用。同时，向番茄叶片喷洒 15mg/L（增强）或 30mg/L（无显著影响）的 BNPs 均对 HL 下的 PSII 功能没有任何显著影响，这归因于缺乏半导体氧化物相和减少光化学毒性的修饰。建议使用叶绿素荧光成像分析作为监测 NPs 在植物上行为的工具。
