Effect of Root Surface Iron Plaque on Se Translocation and Uptake by Fe-Deficient Rice

Under anaerobic conditions, ferric hydroxide deposits on the surface of rice roots and affects uptake and translocation of certain nutrients. In the present study, rice plants were cultured in Fe-deficient or sufficient solutions and placed in a medium containing selenium （Se） for 2 h. Then, FeSO4 was added at the various concentrations of 0, 10, 40, or 70 mg L-1 to induce varying levels of iron plaque on the root surfaces and subsequent uptake of Se was monitored. The uptake of Se was inhibited by the iron plaque, with the effect proportional to the amount of plaque induced. The activity of cysteine synthase was decreased with increasing amounts of iron plaque on the roots. This may be the important reason for iron plaque inhibition of Se translocation. At each level of iron plaque, Fe-deficient rice had more Se than Fe-sufficient rice. Furthermore, with plaque induced by 20 mg Fe L-1, plants from Fe-deficient media accumulated more Se than those from Fe-sufficient media, as the Se concentration was increased from 10 to 30 or 50 mg L^-1. We found that phytosiderophores, highly effective iron chelating agents, could desorb selenite from ferrihydrite. Root exudates of the Fe-deficient rice, especially phytosiderophores in the exudates, could enhance Se uptake by rice plants with iron plaque.

在厌氧的条件下面，铁的氢氧化物在米饭根的表面上扔并且影响某些营养素的举起和 translocation。在现在的学习，米饭植物在 Fe 缺乏或足够的答案是有教养的并且为 2 h 在中等包含硒(Se ) 放了。然后， FeSO4 在 0， 10， 40，或 70 mg L 的各种各样的集中被增加 ? 1 被监视在根表面和 Se 的随后的举起上导致铁匾的变化层次。Se 的举起被铁匾禁止，与与导致的匾的数量成正比的效果。半胱氨酸 synthase 的活动与在根上增加铁匾的数量被减少。这可以是为 Se translocation 的铁匾抑制的重要原因。在铁匾的每水平， Fe 缺乏的米饭比 Fe 足够的米饭有更多的 Se。而且，由 20 mg Fe L 与匾导致了 ? 1，从 Fe 缺乏的媒介的植物从 Fe 足够的媒介比那些积累了更多的 Se，， Se 集中从 10 ～ 30 或 50 mg L 被增加 ? 1。我们发现了那 phytosiderophores，高度有效的铁 chelating 代理人，能使放出从 ferrihydrite 的亚硒酸盐。Fe 缺乏的米饭的根流出物，特别在流出物的 phytosiderophores，能用铁由米饭植物提高 Se 举起匾。