Variation in arsenic accumulation and translocation among wheat cultivars: The relationship between arsenic accumulation, efflux by wheat roots and arsenate tolerance of wheat seedlings

Fifty-seven wheat cultivars were used to investigate the differences in arsenic (As) accumulation, efflux and translocation among wheat cultivars and their relationship with arsenate (As(V)) tolerance under hydroponic condition. The relationship between wheat root As accumulation, As(V) uptake, arsenite (As(III)) efflux and As(V) tolerance of 14 wheat cultivars were also investigated. The results showed there were significant (p < 0.001) differences in As(V) tolerance, As accumulation and translocation among 57 wheat cultivars. Arsenate tolerance of wheat seedlings was positively correlated with As(V) uptake (p < 0.05), root As concentration (p < 0.001), but negatively correlated (p < 0.05) with TFs and relative As(III) efflux. No significant correlation between As(III) efflux and As(V) tolerance was found (p = 0.442). 56-83% of total As taken up by roots was extruded to nutrient solution. Root As concentration was positively correlated with As(V) uptake (not significant, p = 0.100), negatively correlated (p < 0.001) with relative As(III) efflux, whereas not significantly correlated (p = 0.773) with As(III) efflux. The results indicated that As(V) tolerant wheat cultivars have much higher capacity of root As accumulation. Arsenic detoxification in root cells is important for wheat seedlings under As(V) exposure.