Different Anionic Iron Fertilizers FeCl₃ And Fe₂（SO₄）₃ Reduced Cadmium Accumulation In Dwarf Polish Wheat Seedlings

Cd is a non-essential element of organism.It affects the normal growth and development of plant by inhibiting photosynthesis,destroying the structure of cell chloroplast,mitochondria and endoplasmic reticulum;meanwhile it also directly or indirectly enters into the human body,endangering human health.The application of iron（Fe）,nitrogen,phosphorus,zinc,and potassium/calcium fertilizers can effectively reduce the uptake and accumulation of Cd.Feis an essential trace element of organism,which participates in photosynthesis,respiration and chlorophyll biosynthesis of plant.Previous studies show that iron fertilizers with different anions reduce Cd uptake and accumulation in rice and Arabidopsis,but little information is reported in wheat.Since,Dwarf Polish wheat（DPW,Triticum polonicum L.）is high tolerance to Cd and accumulates high Fein plant,it is a desirable material for investigating the effect of FeCl₃ and Fe₂（SO₄）₃ on Cd uptake and accumulation.In the present study,the effects of FeCl₃ and Fe₂（SO₄）₃ on Cd uptake and accumulation in DPW seedlings were investigated by analyzing the root parameters,concentration of Cd and Fe,the subcellular distribution of Cd,the chemical forms of Cd,the sugar content and the transcriptome analysis in root.The main results are as follows:（1）Compared with Fedeficiency,supply of Fefertilizer significantly reduced the uptake and accumulation of Cd in plants,but promoted the translocation from roots to shoots of Cd;it significantly increased the absorption and accumulation of Fein plants,but inhibited the translocation of Fe.The effects of Cl^-and SO₄^2-on Cd reduction were different.When supply with 50μM Fe³⁺,FeCl₃ decreased the root Cd concentration more significantly than Fe₂（SO₄）₃.When supply with 200μM Fe³⁺,Fe₂（SO₄）₃decreased the root Cd concentration more significantly than FeCl₃.Compared with Fe₂（SO₄）₃,FeCl₃significantly promoted the translocation of Cd from root to shoot.（2）The concentrations of Cd and Fein roots were not significantly correlated with the root morphological parameters and plant biomass.（3）Compared with Fedeficiency,the supply of Fefertilizer significantly reduced the concentration of Cd in F_S and F_CW,and increased the concentrations of Fein F_CW of root and shoot.There was a significant negative correlation between the concentration of Cd and Fein root,and a significant negative correlation between TF of Cd with the concentrations of Cd in root F_S and F_CW,and a significant positive correlation between TF of Cd with the concentrations of Fein F_S and F_CW of root.The concentrations of Cd in three fractions of root was negatively correlated with the concentrations of trehalose and sucrose in root,while,the concentrations of Fein the three fractions of root was positively correlated with the concentration of fructose in root.These results indicated that the decrease of Cd concentration in roots might result from the competed binding between Cd and Fein cell wall.When supply with 50μM Fe³⁺,FeCl₃ reduced Cd concentrations of root F_E,F_W,F_NaCland shoot F_E,F_W,F_NaCl and F_HAC more than Fe₂（SO₄）₃.When the concentration of Fe³⁺was200μM,FeCl₃ decreased the Cd concentration of root F_E and F_W,but increased the Cd concentration of root F_NaCl and shoot F_E,F_NaCl,F_HAC and F_HCl,and decreased the Cd conentration of shoot F_W more than Fe₂（SO₄）₃.Cl^-and SO₄^2-differently changed the subcellular distribution and chemical forms of Cd which finally regulating its uptake and accumulation.（4）Under Cd stress,Fe₂（SO₄）₃ and FeCl₃ differentially changed the expression levels of genes encoding metal transporters,thus affecting the absorption and accumulation of Cd.Fefertilizers differentially regulated gene encoding the metal transporters including ABC family,ZIP family,HMA family,YSL family and MATE family,and so on.