Abstract：
The ubiquitous metalloid arsenic (As), which is not essential, can be found extensively in the soil and subterranean water of numerous nations, raising substantial apprehensions due to its impact on both agricultural productivity and sustainability. Plants exposed to As often display morphological, physiological, and growth-related abnormalities, collectively leading to reduced productivity. Polyphenols, operating as secondary messengers within the intricate signaling networks of plants, assume integral functions in the acquisition of resistance to diverse environmental stressors, including but not limited to drought, salinity, and exposure to heavy metals. The pivotal roles played by polyphenols in these adaptive processes underscore their profound significance in plant biology. This study aims to elucidate the impact of hesperidin (HP) and chlorogenic acid (CA), recognized as potent bioactive compounds, on maize plants exposed to As. To achieve this objective, the study examined the physiological and biochemical impacts, including growth parameters, photosynthesis, and chloroplastic antioxidants, of HP (100 μM) and CA (50 μM) on Zea mays plants exposed to arsenate stress (AsV, 100 μM - Na2HAsO4⋅7H2O). As toxicity led to reductions in fresh weight (FW) and dry weight (DW) by 33% and 26%, respectively. However, the application of As+HP and As + CA increased FW by 22% and 40% and DW by 14% and 17%, respectively, alleviating the effects of As stress. As toxicity resulted in the up-regulation of PSII genes (psbA and psbD) and PSI genes (psaA and psaB), indicating a potential response to the re-formation of degraded regions, likely driven by the heightened demand for photosynthesis. Exogenous HP or/and CA treatments effectively counteracted the adverse effects of As toxicity on the photochemical quantum efficiency of PSII (Fv/Fm). H2O2 content showed a 23% increase under As stress, and this increase was evident in guard cells when examining confocal microscopy images. In the presence of As toxicity, the chloroplastic antioxidant capacity can exhibit varying trends, with either a decrease or increase observed. After the application of CA and/or HP, a significant increase was observed in the activity of GR, APX, GST, and GPX enzymes, resulting in decreased levels of H2O2 and MDA. Additionally, the enhanced functions of MDHAR and DHAR have modulated the redox status of ascorbic acid (AsA) and glutathione (GSH). The HP or CA-mediated elevated levels of AsA and GSH content further contributed to the preservation of redox homeostasis in chloroplasts facing stress induced by As. In summary, the inclusion of HP and CA in the growth medium sustained plant performance in the presence of As toxicity by regulating physiological and biochemical characteristics, chloroplastic antioxidant enzymes, the AsA-GSH cycle and photosynthesis processes, thereby demonstrating their significant potential to confer resistance to maize through the mitigation of As-induced oxidative damage and the safeguarding of photosynthetic mechanisms.
摘要：
普遍存在的类金属砷(As)，这不是必需的，可以在许多国家的土壤和地下水中广泛发现，由于其对农业生产力和可持续性的影响，引起了大量的担忧。暴露于As的植物经常显示形态，生理,和生长相关的异常，集体导致生产力下降。多酚,在复杂的植物信号网络中作为二级信使运行，在获得对不同环境压力的抵抗力方面承担整体功能，包括但不限于干旱，盐度,接触重金属。多酚在这些适应过程中发挥的关键作用强调了它们在植物生物学中的深远意义。本研究旨在阐明橙皮苷（HP）和绿原酸（CA）的影响，被认为是有效的生物活性化合物，在暴露于As的玉米植株上。为了实现这一目标,这项研究检查了生理和生化影响，包括生长参数，光合作用,和含氯塑料抗氧化剂，暴露于砷酸盐胁迫的玉米植物上的HP（100μM）和CA（50μM）（AsV，100μM-Na2HAsO4·7H2O)。由于毒性导致鲜重（FW）和干重（DW）减少了33％和26％，分别。然而,As+HP和As+CA的应用增加了22%和40%的FW和14%和17%的DW,分别,减轻As压力的影响。由于毒性导致PSII基因（psbA和psbD）和PSI基因（psaA和psaB）的上调，表明对退化区域重新形成的潜在反应，可能是由于光合作用需求的增加。外源性HP或/和CA处理有效地抵消了As毒性对PSII的光化学量子效率（Fv/Fm）的不利影响。H2O2含量在As胁迫下增加23%，当检查共聚焦显微镜图像时，这种增加在保卫细胞中是明显的。在存在As毒性的情况下,叶绿体抗氧化能力可以表现出不同的趋势，观察到减少或增加。应用CA和/或HP后，观察到GR活性显著增加，APX,GST,和GPX酶，导致H2O2和MDA水平降低。此外,MDHAR和DHAR功能的增强调节了抗坏血酸（AsA）和谷胱甘肽（GSH）的氧化还原状态。HP或CA介导的AsA和GSH含量的升高进一步有助于在面临As诱导的胁迫的叶绿体中保持氧化还原稳态。总之,在生长培养基中包含HP和CA，通过调节生理和生化特性，在砷毒性存在下维持植物性能，叶绿体抗氧化酶，AsA-GSH循环和光合作用过程，从而证明了它们通过减轻As诱导的氧化损伤和保护光合机制来赋予玉米抗性的巨大潜力。
