Illés Peter, Schlicht Markus, Pavlovkin Ján, Lichtscheidl Irene, Baluska Frantisek, Ovecka Miroslav
Institute of Botany, Slovak Academy of Sciences, Dubravska cesta 14, SK-845 23 Bratislava, Slovakia.
J Exp Bot. 2006;57(15):4201-13. doi: 10.1093/jxb/erl197. Epub 2006 Nov 3.
The extent of aluminium internalization during the recovery from aluminium stress in living roots of Arabidopsis thaliana was studied by non-invasive in vivo microscopy in real time. Aluminium exposure caused rapid depolarization of the plasma membrane. The extent of depolarization depends on the developmental state of the root cells; it was much more extensive in cells of the distal than in the proximal portion of the transition zone. Also full recovery of the membrane potential after removal of external aluminium was slower in cells of the distal transition zone than of its proximal part. Using morin, a vital marker dye for aluminium, and FM4-64, a marker for endosomal/vacuolar membranes, an extensive aluminium internalization was recorded during the recovery phase into endosomal/vacuolar compartments in the most aluminium-sensitive cells. Interestingly, aluminium interfered with FM4-64 internalization and inhibited the formation of brefeldin A-induced compartments in these cells. By contrast, there was no detectable uptake of aluminium into cells of the proximal part of the transition zone and the whole elongation region. Moreover, cells of the distal portion of the transition zone emitted large amounts of nitric oxide (NO) and this was blocked by aluminium treatment. These data suggest that aluminium internalization is related to the most sensitive status of the distal portion of the transition zone towards aluminium. Aluminium in these root cells has impact on endosomes and NO production.
通过非侵入性体内实时显微镜技术，研究了拟南芥活体根在从铝胁迫中恢复过程中铝内化的程度。铝暴露导致质膜迅速去极化。去极化的程度取决于根细胞的发育状态；在过渡区远端细胞中的去极化比近端部分更为广泛。此外，去除外部铝后，远端过渡区细胞的膜电位完全恢复比其近端部分要慢。使用铝的活体标记染料桑色素和内体/液泡膜标记物FM4-64，在恢复阶段，在对铝最敏感的细胞中，记录到大量铝内化进入内体/液泡区室。有趣的是，铝干扰了FM4-64的内化，并抑制了这些细胞中布雷菲德菌素A诱导区室的形成。相比之下，在过渡区近端部分和整个伸长区的细胞中未检测到铝的摄取。此外，过渡区远端部分的细胞释放大量一氧化氮（NO），而铝处理可阻断这种释放。这些数据表明，铝内化与过渡区远端部分对铝的最敏感状态有关。这些根细胞中的铝对内体和NO产生有影响。
