稀土在天然植物铁芒萁体内结合形式的光谱学研究  

Studies of Bound Form on Rare Earths in a Natural Plant Fern Dicranopteris Dichotoma by Spectroscopy

作　　者：洪法水[1] 魏正贵[2] 赵贵文[2] 

机构地区：[1]苏州大学生命科学学院生物系,苏州215006 [2]中国科学技术大学化学系,合肥230026

出　　处：《高等学校化学学报》2001年第11期1790-1794,共5页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金 (批准号 :2 980 5 0 0 3);苏州大学人才引进基金资助

摘　　要：利用 ICP-MS研究了江西赣州沙河稀土矿区天然植物铁芒萁体内稀土元素的分布规律 ,发现叶片和叶绿素中 Ce含量最高 ,分别占其稀土总量的 79.4 3%和 6 6 .71 % .铁芒萁叶片光系统 ( PS )荧光发射峰较普通植物紫移 1 5～ 2 5 nm,且峰强是 PS 的 6 .79倍 ,表明 PS 活性提高 .由于铁芒萁叶绿素中稀土叶绿素含量较低 (约占叶绿素总量的 0 .1 % ) ,测定的 UV-Vis和 FTIR光谱特征与标样叶绿素 a相似 ,未能反映出稀土的配位信息 .而利用 EXAFS则表征出在铁芒萁叶绿素中 Ce为八配位 ,Ce—N键长为 0 .2 5 2 nm,推测 Ce是与两个卟啉环配位的 。Distribution of RE and structure characterization of RE chlorophyll in a natural plant fern Dicranopteris Dichotoma in rare earth mining area were studied by spectrocopy. The results showed that the cerium content in total rare earths(79.43%, 66.71%) was the highest in leaf and chlorophyll, respectively. The fluorescence emission peaks of photosystem Ⅱ in D. Dichotoma were more violet shift by 15～25 nm than that of common plant. The fluorescence intensity of photosystem Ⅱ was as 6.79 time as that of photosystem Ⅰ. It showed that RES can increase the activities of photosystem Ⅱ. The spectral characterization of UV Vis and FTIR on chlorophyll a in D. dichotoma are similar as standard chlorophyll a and couldn′t suggest coordination information on REs for its very low contents of RE chlorophyll in \{ D. Dichotoma \}. Extended X ray absorption fine structure(EXAFS) spectral analysis revealed that cerium coordinated two porphyrin rings with coordination number of eight, the bond length of Ce-N was 0\^252 nm, respectively; Ce chlorophyll a may have bilayer structure in D. Dichotoma .

关 键 词：稀土元素 铁芒萁 叶绿素 EXAFS 结合形式 光谱学 铈 配位 

分 类 号：Q954.11[生物学—动物学] Q946.911