Silicon enhances resistance to antimony toxicity in the low-silica rice mutant, lsi1

A solution culture experiment was designed to determine whether Si can alleviate Sb toxicity in rice. The design involved a rice mutant with low Si accumulation and wild-type rice with normal Si accumulation. The effects of Si on rice Sb stress in the presence or absence of P were investigated. P significantly increased the shoot biomass in both wild-type and mutant rice, whereas Si increased the biomass only in the wild-type rice. No biomass change was detected in both rice type when 10 or 30 mu mol.L-1Sb was added to the solution. Compared with the no P control, in both rice types, the application of 0.7 mmol.L-1 P significantly increased the P content, whereas Si significantly influenced the uptake and accumulation of P and Sb. In different P and Sb treatments, 1.0 mmol.L-1 Si led to 6.9-58.2% and 21.4-62.5% decreased Sb content in the shoots of wild-type and mutant rice, respectively. Si addition also significantly impacted the distribution coefficient of Sb between the shoots and seeds of both rice types. These results suggest that the application of Si in rice can promote growth, reduce Sb accumulation and decrease Sb movement to shoot and seeds, which may lead to Sb pollution control under rice field conditions.