Table_2_ZnO nanoparticles efficiently enhance drought tolerance in Dracocephalum kotschyi through altering physiological, biochemical and elemental contents.xls

Using nanofertilizers in certain concentrations can be a novel method to alleviate drought stress effects in plants as a global climate problem. We aimed to determine the impacts of zinc nanoparticles (ZnO-N) and zinc sulfate (ZnSO4) fertilizers on the improvement of drought tolerance in Dracocephalum kotschyi as a medicinal-ornamental plant. Plants were treated with three doses of ZnO-N and ZnSO4 (0, 10, and 20 mg/l) under two levels of drought stress [50% and 100% field capacity (FC)]. Relative water content (RWC), electrolyte conductivity (EC), chlorophyll, sugar, proline, protein, superoxide dismutase (SOD), polyphenol oxidase (PPO) and, guaiacol peroxidase (GPO) were measured. Moreover, the concentration of some elements interacting with Zn was reported using the SEM-EDX method. Results indicated that foliar fertilization of D. kotschyi under drought stress with ZnO-N decreased EC, while ZnSO4 application was less effective. Moreover, sugar and proline content as well as activity of SOD and GPO (and to some extent PPO) in treated plants by 50% FC, increased under the influence of ZnO-N. ZnSO4 application could increase chlorophyll and protein content and PPO activity in this plant under drought stress. Based on the results, ZnO-N and then ZnSO4 improved the drought tolerance of D. kotschyi through their positive effects on physiological and biochemical attributes changing the concentration of Zn, P, Cu, and Fe. Accordingly, due to the increased sugar and proline content and also antioxidant enzyme activity (SOD, GPO, and to some extent PPO) on enhancing drought tolerance in this plant, ZnO-N fertilization is advisable.

采用特定浓度的纳米肥料作为一种应对全球气候变化带来的干旱胁迫问题的创新方法，本研究旨在探究锌纳米颗粒（ZnO-N）和硫酸锌（ZnSO4）肥料对药用观赏植物 Dracocephalum kotschyi抗旱性的影响。实验中，植物分别接受了三种剂量的ZnO-N和ZnSO4（0、10和20 mg/L）处理，并在两种干旱胁迫水平（50%和100%田间持水量）下进行。通过测量相对含水量（RWC）、电导率（EC）、叶绿素、糖、脯氨酸、蛋白质、超氧化物歧化酶（SOD）、多酚氧化酶（PPO）和愈创木酚过氧化物酶（GPO）等生理生化指标，同时利用扫描电子显微镜-能谱仪（SEM-EDX）方法报告了与锌相互作用的某些元素浓度。结果表明，在干旱胁迫下，对D. kotschyi进行叶面施肥的ZnO-N降低了电导率，而ZnSO4的应用效果则相对较差。此外，在50%田间持水量下，ZnO-N处理显著提高了处理植物的糖和脯氨酸含量，以及SOD和GPO（在一定程度上PPO）的活性。ZnSO4的应用在干旱胁迫条件下能够增加植物的叶绿素和蛋白质含量，并提高PPO的活性。基于研究结果，ZnO-N和ZnSO4通过改变锌、磷、铜和铁等元素的浓度，对D. kotschyi的抗旱性产生了积极影响。鉴于ZnO-N施肥能够增加植物的糖和脯氨酸含量以及抗氧化酶活性（SOD、GPO和在一定程度上PPO），从而增强其抗旱性，因此建议采用ZnO-N进行施肥。