Arsenic(As)and Cadmium(Cd)Accumulation And Distribution In Wheat (Triticum Aestivum L.) And The Influce Of Phosphate And Silicate

Arsenic(As)and cadmium(Cd)contanmination in soil can lead to accumulation in wheat and other cereals.Chronic consumption of contaminated wheat will cause potential health risks for human.In order to avoid this risk,it is necessary to understand As and Cd distribution and accumulation in wheat at different growth stages.Four wheat cultivars,such as Jining 12(JN12)?Jinmai85(JM85)?Qingfeng1(QF1)and Xiaoyan22(XY22)were used to invastigate As and Cd concentrations in different parts of wheat plants(root?stem?internode?leaf?rachis?husk and grain)in response to wheat growth stages(tillering stage?elongation stage?anthesis?grain filling stage and maturity).The effects of phosphate and silicate on As distribution in wheat at maturity were also been studied.The present results showed that As concentrations in various parts of wheat plants were in the order of root>leaf>internode>rachis>Husk>grain,and the order of Cd concentrations in different wheat parts wassimilar to As.As concentrations in all parts of wheat plants wereincreased with wheat growth.However,the similar trends were not found in Cd concentration in wheat plants except forthose in leaf,first internode(I-I)and grain.Nodes play an important role to control As and Cd translocation to upper position of wheat.Grain As concentrations are positively correlated(P<0.05)with TF(Grain/Root)?TF(Grain/Stem)and TF(Grain/L-I)of As at grain filling and maturity stage.Cd concentrations in grain are significantly positively correlated(P<0.05)with TF(Grain/Root)and TF(Grain/Rachis)of Cd at grain filling and maturity stage,respectively.As concentrations in rachis and Husk increased 9.90 and 9.76 times respectively at grain filling stage than those at anthesis stage.Average grain As concentrations of four cultivars increased significantly from grain filling to maturity stage,with the average increase of 50.3%.Grain As concentrations in JM85 and QF1 were significantly higher than those of XY22 and JN12 at maturity stage.The Cd concentrations in rachis,husk and grain at mature stage were significantly higher than those at grain filling stage.Not similar to As,Cd concentrations in rachis and husk were both significantly reduced at grain filling stage,but increased at maturity stage.There are significant differences among the cultivars.Grain Cd concentrations of JM85 was significantly lower than those of others cultivars.Phosphate and silicate have obvious effects As uptake and transportation in wheat,and the distribution of As in wheat was changed after adding phosphate into soil and spraying silicate on leaf surface.Both As in soil solution and wheat plants were increased after the addition of phosphateto As contamination soil.As in wheat plants was reduced when silicate was sprayed on wheat leaf surface,and the more obvious declinewas found in higher contamination soil than in lower contamination soil.