Jones D L, Blancaflor E B, Kochian L V, Gilroy S
School of Agricultural and Forest Sciences, University of Wales, Bangor, Gwynedd, LL57 2UW, UK.
Plant Cell Environ. 2006 Jul;29(7):1309-18. doi: 10.1111/j.1365-3040.2006.01509.x.
Aluminium (Al) toxicity associated with acid soils represents one of the biggest limitations to crop production worldwide. Although Al specifically inhibits the elongation of root cells, the exact mechanism by which this growth reduction occurs remains controversial. The aim of this study was to investigate the spatial and temporal dynamics of Al migration into roots of maize (Zea mays L.) and the production of the stress response compound callose. Using the Al-specific fluorescent probe morin, we demonstrate the gradual penetration of AI into roots. Al readily accumulates in the root's epidermal and outer cortical cell layers but does not readily penetrate into the inner cortex. After prolonged exposure times (12-24 h), Al had entered all areas of the root apex. The spatial and temporal accumulation of Al within the root is similarly matched by the production of the cell wall polymer callose, which is also highly localized to the epidermis and outer cortical region. Exposure to Al induced the rapid production of reactive oxygen species and induced a significant rigidification of the cell wall. Our results suggest that Al-induced root inhibition in maize occurs by rigidification of the epidermal layers.
与酸性土壤相关的铝（Al）毒性是全球作物生产的最大限制因素之一。尽管铝特异性地抑制根细胞的伸长，但这种生长减少发生的确切机制仍存在争议。本研究的目的是研究铝向玉米（Zea mays L.）根中迁移的时空动态以及应激反应化合物胼胝质的产生。使用铝特异性荧光探针桑色素，我们证明了铝逐渐渗透到根中。铝很容易在根的表皮和外皮层细胞层中积累，但不容易渗透到内皮层。在长时间暴露（12 - 24小时）后，铝进入了根尖的所有区域。根内铝的时空积累与细胞壁聚合物胼胝质的产生类似地匹配，胼胝质也高度定位于表皮和外皮层区域。暴露于铝会诱导活性氧的快速产生，并导致细胞壁显著硬化。我们的结果表明，铝诱导的玉米根抑制是通过表皮层的硬化发生的。
