Xu Xiang-Hua, Li Ren-Ying, Liu Cui-Ying, Shi Ji-Yan, Lin Jia
Jiangsu Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China.
College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310029, China.
Huan Jing Ke Xue. 2013 Nov;34(11):4460-5.
Phytolacca americana L. (P. americana) is a manganese (Mn) hyperaccumulator plant discovered in southern China, and knowledge of Mn uptake characteristics and mechanisms on this plant may provide essential and critical information for phytoremediation. Synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) microprobe was empolyed in this study to explore the Mn distribution in the root cross-section of P. americana, and effects of metabolic inhibitors (DNP and Na3VO4) and Ca-channel inhibitor (LaCl3) on Mn uptake of P. americana was also investigated under laboratory conditions. Results showed that P. americana has strong abilities for absorpting and accumulating Mn, and the Mn concentration in root, stem, and leaf of P. americana may reach up to 402, 208, and 601 mg x kg(-1) DW, respectively, even only treated with 5 micromol x L(-1) Mn. The highest Mn content can be found in the vascular bundle of root, and then the epidermis, while the lowest Mn content can be observed in the cortex. The Mn content increased when shifted from cortex to vascular bundle, indicating that there was an active transportation in Mn absorption of P. americana root, and the inhibitory effect of DNP and Na3VO4 on Mn uptake further verified the possibilities of active absorption. The Mn uptake was inhibited by 30% with LaCl3, suggesting that Mn uptake in P. americana also closely related to the Ca-channel.
美洲商陆是在中国南方发现的一种锰超积累植物，了解该植物对锰的吸收特性和机制可能为植物修复提供重要关键信息。本研究采用同步辐射X射线荧光光谱（SRXRF）微探针探究美洲商陆根横切面中锰的分布，并在实验室条件下研究代谢抑制剂（二硝基苯酚和钒酸钠）和钙通道抑制剂（氯化镧）对美洲商陆吸收锰的影响。结果表明，美洲商陆具有很强的吸收和积累锰的能力，即使仅用5 μmol·L⁻¹锰处理，美洲商陆根、茎和叶中的锰浓度分别可达402、208和601 mg·kg⁻¹ DW。根中维管束的锰含量最高，其次是表皮，而皮层中的锰含量最低。从皮层到维管束，锰含量增加，表明美洲商陆根吸收锰存在主动运输，二硝基苯酚和钒酸钠对锰吸收的抑制作用进一步证实了主动吸收的可能性。氯化镧使锰吸收受到30%的抑制，表明美洲商陆吸收锰也与钙通道密切相关。
