Study On The Effects And Mechanisms Of Hydrogen-Rich Water On Alleviating Iron Deficiency Stress In Maize(Zea Mays L.)

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.