根表铁膜对水稻吸收转运稀土元素Ce的影响

采用溶液培养的方法探讨根表铁膜形成对水稻吸收积累和转运稀土元素Ce的影响。结果表明,Ce污染胁迫可抑制水稻根表铁膜的形成,根表铁膜吸附的Ce量随着溶液中Ce浓度的提高而增加。根表铁膜形成可降低水稻根系但提高水稻茎叶对Ce的吸收积累。当溶液中Ce浓度为0.1、0.5和1.0 mmol·L~(-1)时,铁膜诱导组水稻根系Ce含量分别比非诱导组水稻根系Ce含量降低38.60%、45.94%和32.75%,诱导组水稻茎叶Ce含量分别比非诱导组水稻茎叶Ce含量提高42.37%、28.87%和22.62%。根表铁膜形成可影响Ce在水稻植株中的富集和转运能力。非诱导组水稻根系富集Ce的能力远大于茎叶。诱导组水稻根系对Ce的富集能力最强,其次是根表铁膜,最后是水稻茎叶。诱导组水稻根系Ce转运系数显著大于非诱导组的根系,说明根表铁膜形成可促进水稻根部Ce向茎叶中转运。可见,根表铁膜对水稻吸收转运稀土元素的影响机理比较复杂。

Effect of Root Surface Iron Plaque on Uptake and Translocation of Cerium (Rare Earth Element) in Rice Seedlings

Effect of iron plaque formation of root surface on uptake, accumulation and translocation of Ce (rare earth element) by rice seedlings was evaluated by method of solution culture experiment. The result showed that Ce pollution stress could inhibit the formation of root surface iron plaque in rice seedlings, the amount of Ce which was uptaken by root surface iron plaque increased with the increase of Ce concentration in the solution. The iron plaque formation of root surface could decrease the uptake and accumulation of Ce by rice root system, but increase uptake and accumulation of Ce by rice stem and leaves. When Ce concentration in the solution is 0.1, 0.5 and 1.0 mmol?L^-1, Ce content by rice roots with iron plaque induced group was decreased by 38.60%, 45.94% and 32.75% respectively when comparing with non-induced group, and Ce content by stem and leaves with iron plaque induced group was increased by 42.37%, 28.87% and 22.62% respectively when comparing with non-induced group. The formation of iron plaque on root surface could influnce the accumulation and translocation of Ce in rice seedlings. The ability which rice roots accumulated Ce element was greater than that of the stem and leaves in non-induced group. The ability of accumulating Ce element was the strongest in rice roots in induced-group, followed by root surface iron plaque, and the last was the rice leaves and stem. The enrichment coefficient of rice roots in iron plaque induced group was significantly greater than that of rice roots in non-induced group, which meant iron plaque formation on root surface could increase Ce transfer from rice roots to stem and leaves. Thus, effect of root surface iron plaque on uptake and translocation of Ce element in rice seedlings was comparatively complicated.