Distribution and speciation of Mn in hydrated roots of cowpea at levels inhibiting root growth

作者：Kopittke Peter M^*; Lombi Enzo; McKenna Brigid A; Wang Peng; Donner Erica; Webb Richard I; Blamey F Pax C; de Jonge Martin D; Paterson David; Howard Daryl L; Menzies Neal W

来源：Physiologia Plantarum, 2013, 147(4): 453-464.

DOI：10.1111/j.1399-3054.2012.01674.x

The phytotoxicity of Mn is important globally due to its increased solubility in acid or waterlogged soils. Short-term (24 h) solution culture studies with 150 mu M Mn were conducted to investigate the in situ distribution and speciation of Mn in apical tissues of hydrated roots of cowpea [Vigna unguiculata (L.) Walp. cv. Red Caloona] using synchrotron-based techniques. Accumulation of Mn was rapid; exposure to 150 mu M Mn for only 5 min resulting in substantial Mn accumulation in the root cap and associated mucigel. The highest tissue concentrations of Mn were in the root cap, with linear combination fitting of the data suggesting that80% of this Mn(II) was associated with citrate. Interestingly, although the primary site of Mn toxicity is typically the shoots, concentrations of Mn in the stele of the root were not noticeably higher than in the surrounding cortical tissues in the short-term (24 h). The data provided here from the in situ analyses of hydrated roots exposed to excess Mn are, to our knowledge, the first of this type to be reported for Mn and provide important information regarding plant responses to high Mn in the rooting environment.

• 出版日期2013-4