美洲商陆对锰毒生理响应的FTIR研究

在一定Mn浓度梯度处理下(0,0.125,0.25,0.5,1 g·kg-1)，超积累植物——美洲商陆(Phytolacca americana)不同组织器官的傅里叶变换红外光谱(FTIR)图谱发生了变化。其中，茎组织在3 336和2 916 cm-1处峰高先上升后下降，反映了有机物运输受阻情况的变化，即美洲商陆在低Mn刺激下会产生大量有机物作为渗透调节物质来增强其耐Mn性，高Mn则抑制了有机物的分泌和运输；根和叶组织分别在2 922和1 606 cm-1处表现不同变化趋势，但都反映了一个变化规律即低Mn处理下美洲商陆分泌的有机酸不断螯合Mn，随着Mn毒害的加重，其羧酸螯合力变弱；根组织1 732和1 026 cm-1、茎组织1 028 cm-1、叶组织1 052和967 cm-1处呈现差异性变化，但都与其膜脂过氧化有关；根组织1 375 cm-1处峰高先上升后下降，可能与植物在细胞壁结构上增强抗逆性有一定关系，即低Mn处理下细胞壁可能通过阳离子交换能力(CEC)的提高增强了耐Mn性。以上说明，利用FTIR研究重金属超积累植物化学组分具有应用价值。

Studies on the Physiological Response of Phytolacca Americana to Manganese Toxicity by FTIR Spectroscopy

A technique based on Fourier transform infrared (FTIR) spectrometry was used to detect the physiological changes in chemical composition of Phytolacca americana under a wide range of Mn2+ treatments (0, 0.125, 0.25, 0.5 and 1 g x kg(-1)). Using the roots, stems and leaves of phytolacca americana, absorption bands corresponding to carbohydrates, ester and proteins varied differently. The absorption band heights at 3 000 and 2 916 cm(-1) of stem tissues rose firstly and then decreased, indicating the exudation and transporting situation of organic substances which served as organic osmotic contents to enhance manganese tolerance under low treatments; Meanwhile, the band heights at 2 922 cm(-1) (roots) and 1 606 cm(-1) (leaves) which have different tendency in accordance with Mn treatments showed that the capability to chelate Mn decreased under higher manganese concentration. In addition, the changes of the bands at 1 732 and 1 026 cm(-1) (roots), 1 028 cm(-1) (stems), 1 052 and 967 cm(-1) (leaves) differed from each other, suggesting that under the conditions of severe Mn stress the ex-oxidation of membrane lipid increased; Otherwise, the band heights at 1 375 cm(-1) increased firstly and then decreased, representing that the cell wall improved Mn resistance by increasing cation-exchange capacity (CEC). The result also implied that it is practical to apply FTIR to the research comparing the chemical differences of phytoaccumulators under metal treatments.