[Objective]Absorption property of Si uptake in rice crops was studied. [Method]The rice (Oryza sativus L. ) was employed to study absorption property of Si uptake under 0. 085,0. 850 mmol/L Si level by hydroponic experiments. [Result]The total Si uptake was more than Si uptake calculated via transpiration streams under two Si treatments for 12 hours. The two gradually increased with the extension of time. The con-tribution of Si uptake calculated via transpiration streams to total Si uptake was greater at higher Si supply level than at lower Si supply level. Si uptake by rice during 6 hours was inhibited by the treatment with metabolic inhibitors or low temperature at 0. 085,0. 850 mmol/L Si. The degree of inhibition was decreased with increasing external Si concentration. At 0. 085,0. 850 mmol/L Si level,during 12 hours the Si concentrations of the xylem exudates in rice increased with time,but Si concentration in the external solutions decreased with time. And Si concentration was sever-al-fold higher in xylem exudates than in the external solutions. [ Conclusion] There are two processes of active absorption and passive absorption of Si by rice,especially in high Si concentration,passive absorption can not be ignored.%[目的]研究水稻对硅元素的吸收特性.[方法]以水稻为材料,采用水培试验,设置0.085、0.850 mmol/L 2个硅水平,明确水稻对硅的吸收模式.[结果]在2个硅处理下水稻在12 h的总吸硅量明显高于蒸腾吸硅量,二者都随着时间的延长逐渐升高,并且蒸腾吸硅量占总吸硅量的比值表现为高硅浓度处理高于低硅浓度处理;2个处理在6h内的硅吸收都受到了代谢抑制剂和低温的抑制,并且表现为高硅浓度的抑制程度低于低硅浓度的抑制程度;2个处理在12 h内木质部汁液硅浓度随时间的延长逐步升高,而外部溶液硅浓度随时间的延长逐步降低,并且木质部汁液硅浓度比外部溶液的硅浓度高数倍.[结论]水稻对硅的吸收存在主动吸收和被动吸收2个过程,尤其在高硅浓度处理下,被动吸收更不能忽视.
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