镧在轮藻节间细胞中的分布及与细胞壁的结合状态

Distribution in Internodal Cells of Chara and the Bonding States with the Cell Wall of Lanthanum

利用电感耦合等离子体质谱(ICP-MS)和X射线吸收谱(XAS)研究了稀土元素镧在轮藻节间细胞中的分布和配位环境.实验结果发现,4μmol?dm-3LaCl3溶液处理12h,细胞中绝大部分的La存在于细胞壁且结合紧密,各亚细胞组分中La的浓度依次为:细胞壁>>细胞质>>液泡.XAS的结果表明La3+在细胞壁中与9个氧原子配位,配位环境类似于醋酸镧,说明在细胞壁中La3+的主要配位基团是羧基.珊瑚轮藻具有很强的从培养介质中富集La3+的能力,可用于水体中稀土元素的监测与污染治理.

Distribution and coordination environment of lanthanum （La） in internodal cells of Chara have been determined by inductively coupled plasma-mass spectrometry and X-ray absorption spectroscopy （XAS）. The results indicate that after treatment with 4 umol.dm^-3 LaCl3 solution for 12 h, most of La in cells is located in the cell wall fraction and the bonding is tight. The order of La concentrations in the subcellular fractions is cell wall〉〉cytoplasm〉〉vacuole. The results of XAS show that La^3＋ is coordinated to 9 oxygen atoms in the cell wall, and the coordination environment is similar to that of lanthanum acetate, which indicates that La bonds to the cell component via carboxylate groups. According to the high ability of La accumulation, Chara can act as a biological indicator or scavenger of rare earth pollution in aqueous solutions.