土壤施硅对水稻吸收砷的影响

通过盆栽试验研究在2种砷污染土壤中施加硅对水稻幼苗吸收砷的影响.结果表明,施加外源硅没有显著提高幼苗期水稻植株地上部和地下部生物量,也没有显著影响低砷土壤中水稻植株地上部和地下部的磷浓度,却使高砷土壤中水稻植株地上部磷浓度增加18%～39%,但对地下部磷浓度影响不大.同时与不施硅相比,无论是否调节硅酸钾溶液的pH值,施加2种浓度的外源硅均显著降低水稻植株地上部和地下部砷浓度.在低砷土壤中施加2种浓度的外源硅使水稻植株地上部砷浓度降低36%～59%,地下部砷浓度降低15%～37%.在高砷土壤中加硅,地上部砷浓度降低42%～58%,地下部砷浓度降低70%～82%.此结果与水培试验结果相一致,并对可能的机理进行了解释.

Effect of Application of Silicon on Arsenic Uptake by Rice Seedlings in Soil

The objective of study was to investigate effect of silicon on arsenic uptake by rice seedlings in two soils with different arsenic concentrations. The results show that the addition of silicon has little effect on shoot and root dry weights of rice seedlings. The addition of silicon did not affect shoot and root P concentrations of rice seedlings grown in low arsenic soil, but significantly increased shoot P concentrations on rice grown in high arsenic soil. Irrespective of the initial pH of K2SiO3 solution, the addition of silicon significantly decreased shoot and root As concentrations of rice seedlings compared with the control. For seedlings grown in low As- contaminated soil, As concentrations in shoot and root were reduced by 36 % -59 % and 15 % -37 % with the application of silicon, respectively. For seedlings grown in high As-contaminated soil, As concentrations in shoot and root were reduced by 42 % - 58 % and 70 % - 82% with the application of silicon, respectively. These results are in agreement with our previous reports based on a solution culture experiment. Possible mechanisms of the effect of Si on As uptake was also discussed.