Kopittke Peter M, Moore Katie L, Lombi Enzo, Gianoncelli Alessandra, Ferguson Brett J, Blamey F Pax C, Menzies Neal W, Nicholson Timothy M, McKenna Brigid A, Wang Peng, Gresshoff Peter M, Kourousias George, Webb Richard I, Green Kathryn, Tollenaere Alina
Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.)
Schools of Agriculture and Food Sciences (P.M.K., B.J.F., F.P.C.B., N.W.M., B.A.M., P.W., P.M.G., A.T.) andChemical Engineering (T.M.N.) andCentres for Integrative Legume Research (B.J.F., P.M.G., A.T.) andMicroscopy and Microanalysis (R.I.W., K.G.), University of Queensland, St. Lucia, Queensland 4072, Australia;Department of Materials, University of Oxford, Oxford OX1 3PH, United Kingdom (K.L.M.);Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia (E.L.); andTwinMic Beamline, Elettra-Sincrotrone Trieste, 34149 Trieste-Basovizza, Italy (A.G., G.K.).
Plant Physiol. 2015 Apr;167(4):1402-11. doi: 10.1104/pp.114.253229. Epub 2015 Feb 10.
Despite the rhizotoxicity of aluminum (Al) being identified over 100 years ago, there is still no consensus regarding the mechanisms whereby root elongation rate is initially reduced in the approximately 40% of arable soils worldwide that are acidic. We used high-resolution kinematic analyses, molecular biology, rheology, and advanced imaging techniques to examine soybean (Glycine max) roots exposed to Al. Using this multidisciplinary approach, we have conclusively shown that the primary lesion of Al is apoplastic. In particular, it was found that 75 µm Al reduced root growth after only 5 min (or 30 min at 30 µm Al), with Al being toxic by binding to the walls of outer cells, which directly inhibited their loosening in the elongation zone. An alteration in the biosynthesis and distribution of ethylene and auxin was a second, slower effect, causing both a transient decrease in the rate of cell elongation after 1.5 h but also a longer term gradual reduction in the length of the elongation zone. These findings show the importance of focusing on traits related to cell wall composition as well as mechanisms involved in wall loosening to overcome the deleterious effects of soluble Al.
尽管铝（Al）的根毒性在100多年前就已被发现，但对于在全球约40%的酸性耕地土壤中，根系伸长率最初降低的机制仍未达成共识。我们使用高分辨率运动学分析、分子生物学、流变学和先进的成像技术来研究暴露于铝的大豆（Glycine max）根系。通过这种多学科方法，我们确凿地表明铝的主要损伤发生在质外体。特别是，发现75 µm的铝仅在5分钟后（或30 µm铝在30分钟后）就会降低根的生长，铝通过与外层细胞的细胞壁结合而具有毒性，这直接抑制了它们在伸长区的松弛。乙烯和生长素生物合成及分布的改变是第二个较慢的效应，导致在1.5小时后细胞伸长率短暂下降，同时也使伸长区长度长期逐渐缩短。这些发现表明关注与细胞壁组成相关的性状以及参与细胞壁松弛的机制对于克服可溶性铝的有害影响的重要性。
