| Arsenic contamination in agriculture soil and crops is more and more seriously,which resulted in potentially health risk for human being.Wheat is one of three major grains in the world.Arsenic concentration in wheat grains is significantly increased when the plants were grown in As contaminated soil.Thus,it is important to breed and cultivate varieties with higher arsenic-resistance and lower As accumulation in grains for human to ensure food security.In the present study,13 wheat cultivars were used to investigate the relationship of As accumulation and arsenate(As(Ⅴ))tolerance under hydroponic culture.The changes of antioxidant system,arsenite(As(Ⅲ))efflux and non-protein thiols were also studied.The results showed that there were significant differences in As(Ⅴ)tolerance,As accumulation and translocation among different wheat cultivars.As(Ⅴ)tolerance of wheat seedlings was negatively correlated with TFs,but positively correlated with root As concentrations.No significant correlation between As(Ⅴ)tolerance and shoot As concentrations was found.No significant correlation between root and shoot As concentration was found.Nannong 0686 and MV964091 belong to the tolerant varieties.Zhenmai 5 and Yangmai 158 belong to the sensitive varieties.After exposed to 0,5,and 15 μgmol L-1 As(Ⅴ)for 3 days,the relative biomass,root activities and the activities of antioxidant enzymes in the tolerant varieties(Nannong0686 and MV964091)were significantly higher than those in the sensitive varieties(Zhenmai 5 and Yangmai 158).The relative conductivities of roots and shoots of the tolerant varieties were lower than those of the sensitive varieties.The efflux of As(Ⅲ)by wheat roots is a way for wheat seedlings to reduce arsenic accumulation.PCs contents in wheat seedlings were increased significantly under arsenic stress.The PCs contents in roots and shoots of the tolerant varieties were significantly higher than those of the sensitive varieties.PCs may be play an important role for arsenic tolerance of wheat seedlings. |
