Accumulation and detoxification of manganese in hyperaccumulator Phytolacca americana
Accumulation and detoxification of manganese in hyperaccumulator Phytolacca americana
复制标题
超积累植物美洲商陆中锰的积累和解毒。
DOI：
10.1111/j.1438-8677.2008.00163.x
复制
发表时间：
2009-09-01
期刊：
影响因子：
3.9
通讯作者：
Chen, Y. -X.
中科院分区：
文献类型：
--
作者：
Dou, C. -M.;Fu, X. -P.;Chen, Y. -X.
美洲商陆（Phytolacca americana）具有超积累锰的能力，近年来受到广泛关注。然而，锰解毒的内在机制还不完全清楚。本文研究了美洲商陆中锰的积累、亚细胞分布、化学形态和草酸解毒作用。过量的Mn主要以水溶性形式存在于叶片中，超过80%的Mn以水溶性形式存在，而过量的Mn在细胞器和细胞膜中的积累会引起植物毒性。此外，美洲商陆具有固有的高草酸含量。在所有试验中，有足够的草酸螯合锰在叶水提取物在所有不同水平的施锰。X射线衍射物相分析检测到草酸根-锰螯合物，凝胶色谱进一步证实了草酸根对锰的螯合作用。总之，美洲商陆积累过量的锰在叶细胞的可溶性部分，最有可能在液泡，其中锰的解毒可以通过螯合与草酸盐。
Pokeweed (Phytolacca americana) has recently received much attention because of its ability to hyperaccumulate manganese (Mn). The internal mechanism of detoxification of Mn, however, is not fully understood. In the present study, we investigated Mn accumulation, subcellular distribution, chemical speciation and detoxification through oxalate in pokeweed. The plant accumulated excess Mn in the leaves, mainly in the water-soluble fraction, and over 80% of Mn was in a water-soluble form, while accumulation of excess Mn in the cellular organelle and membrane fraction caused phytotoxicity. In addition, pokeweed has an intrinsically high oxalate content. In all experiments, there was sufficient oxalate to chelate Mn in leaf water extracts at all different levels of Mn application. Phase analysis of X-ray diffraction detected oxalate-Mn chelate complexes, and gel chromatography further confirmed the chelation of Mn by oxalate. In conclusion, pokeweed accumulates excess Mn in the soluble fraction of leaf cells, most likely in vacuoles, in which detoxification of Mn could be achieved by chelation with oxalate.