铁是植物必需的微量元素。虽然铁是地壳中的第四大丰富元素，但在通气性良好的碱性或石灰性土壤中，由于铁的有效性低，所以常难以满足植物正常生长发育的需要。近年来，一些研究发现H2作为一种新的生物活性物质，在植物抵御逆境胁迫方面具有重要的作用。因此，本研究主要探讨了HRW对缺铁胁迫下玉米的生理生化及分子特性的影响，探索其对玉米缺铁黄化的调控机理，为农业上缺铁的缓解措施及应用提供相应的理论依据。本文的主要研究结果如下： 1、在缺铁条件下，添加HRW明显缓解了玉米幼苗的黄化现象。 2、在缺铁的玉米植株中，叶肉细胞中叶绿体的光合片层少，基质片层基本消失。相反，缺铁植株经HRW处理后，叶肉细胞中的叶绿体能够发育完全，并具有正常的基质片层垛叠。 3、缺铁植株经HRW处理后，增加了铁的含量，主要通过调控铁的吸收和运输相关基因(ZmMTN、ZmNAS1、ZmNAS3、ZmDMAS1、ZmTOM2)的变化以及增加麦根酸类物质(PSs)的分泌量和积累量，提高了缺铁玉米幼苗根系对铁的吸收。并且在缺铁玉米的根中，Fe(III)-PS的转运体ZmYS1明显被诱导，然而，HRW处理后ZmYS1表达量却下调。 4、在缺铁条件下，添加HRW提高了玉米幼苗的光合作用，主要包括三个方面：一方面，提高了Rubisico和PEPC活性、RBCL、RBCS和D1蛋白(psbA)和PEPC相关基因的表达。另一方面，HRW通过促进叶绿素的合成、叶绿体的发育、PSII的电子传递和元素的平衡等，加强对光能的利用，减少缺铁胁迫下ROS的产生。最后，通过增强抗氧化酶的活性，提高清除ROS的能力。三者共同保护了缺铁胁迫下光合功能的稳定性，从而促进了玉米幼苗的生长和发育。 综上所述，以上结果表明了HRW对玉米缺铁胁迫的缓解效应主要与铁的吸收、转运、积累等密切相关。并且通过提高抗氧化酶活性，保持矿质元素的吸收平衡，最终促进了叶绿素的合成、光合电子的传递、叶绿体的发育和光合作用。

Iron is an essential microelement for plants, although Fe is the fourth abundant element in the earth''''''''s crust, however, in alkaline or calcareous soils with aerobic condition, the bioavailability of Fe is far below the level that required for normal plant growth. In recent years, some studies have shown that H2 is new biologically active substances, and it plays an important role in plant resistance to stress. Therefore, this study mainly discuss the HRW on the physiological, biochemical and molecular characteristics of maize plants under iron deficiency stress, and further explore the regulation mechanism, this can provide the corresponding theoretical basis for the mitigation measures and application of iron deficiency in agriculture. In this paper, the research results are summarized as follows: 1.HRW completely prevented leaf interveinal chlorosis in maize seedlings grown in iron-deficient culture solution. 2.Electron micrographs of mesophyll cells from iron-deficient maize seedlings revealed plastids with few photosynthetic lamellae and rudimentary grana. On the contrary, mesophyll chloroplasts appeared completely developed in HRW-treated maize seedlings. 3.HRW treatment can increase iron uptake in maize roots by changing the expression levels of iron homeostasis-related genes (ZmMTN, ZmNAS1, ZmNAS3, ZmDMAS1, ZmTOM2). Phytosiderophore (PS) accumulation and secretion were also enhanced by HRW treatment in seedlings grown in iron-deficient solution. Indeed, the gene expression of ferric-phytosiderophore transporter (ZmYS1) was specifically induced by iron deficiency in maize roots, whereas their abundance was decreased by HRW treatment. 4.HRW significantly enhanced photosynthesis in maize seedlings grown in iron-deficient solution, including three aspects: On the one hand, HRW improved the activity of Rubisico and PEPC activity, promoted the expression of genes encoding RuBISCO large subunit (RBCL), small subunit (RBCS), PEPC and D1 protein (psbA). On the other hand, HRW enhanced the use of light energy and decreased the production of ROS under iron deficiency by promoting the synthesis of chlorophyll, the development of chloroplast, the electron transfer of PSII and the balance of elements. Finally, HRW improved the ROS scavenging through increasing antioxidant enzymes activities. Three species together to protect the stability of photosynthetic function under iron deficiency condition, thus promoting the growth and development of maize seedlings. Taken together, these results indicate that HRW is closely related to iron uptake, transport, and accumulation,.HRW also improves antioxidant enzyme activities and maintains nutrient homeostasis in maizes plants, thus consequently increases chlorophyll biosynthesis, photosynthetic electron transport, chloroplast development, and photosynthesis in plants.