香根草对镉毒害的生理响应——采用傅里叶变换红外光谱法(FTIR)

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 香根草对镉毒害的生理响应——采用傅里叶变换红外光谱法(FTIR) DOI: 10.5846/stxb201808191763 作者: 作者单位: 重庆三峡学院,重庆市万州区生态环境监测站 重庆万州,重庆市交通规划勘察设计院,重庆三峡学院,西南大学生命科学学院，三峡库区生态环境教育部重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31270451）；三峡库区水环境演变与污染防治重庆高校市级重点实验室开放基金项目（WEPKL2016LL-05） Physiological responses of Vetiveria zizanioides to cadmium stress by fourier transform infrared spectroscopy Author: Affiliation: Chongqing Three Gorges University,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为阐明香根草（Vetiveria zizanioides）对镉（Cd2+）胁迫的耐性机理及其对重金属Cd2+的积累特征，通过水培试验，采用傅里叶变换红外光谱法（FTIR）研究在不同Cd2+浓度处理时香根草根、茎、叶化学组分的变化，同时测定香根草叶Cd2+的亚细胞分布和其重金属Cd2+含量。结果表明，其根组织在2927 cm-1处峰高先下降后上升，表明在低Cd2+（Cd2+<3 mg/L）处理条件下香根草分泌的有机酸不断螯合Cd2+，造成羧酸O-H的减少，但随着Cd2+含量的升高，其羧酸螯合力变弱，有机酸含量渐渐升高；茎组织在1631 cm-1峰高处先上升后下降，表明在低Cd2+（Cd2+<3 mg/L）处理条件下香根草产生氨基酸、多肽和蛋白质等物质，通过渗透调节来增强抗逆性，但随着Cd2+含量的升高，蛋白质二级结构中肽键间氢键的结合力受影响较大。当Cd2+处理浓度为7 mg/L时，香根草生长10 d后，地上部分及根组织富集Cd2+量分别高达212.49 mg/kg和290.59 mg/kg。香根草地上部分的Cd2+含量随Cd2+处理浓度的增加而增加。香根草叶片富集的Cd2+主要分布于细胞质中，其次为细胞壁，而在线粒体和叶绿体中含量最低。 Abstract:Heavy metal pollution caused by industrial sewage and agricultural production is becoming an increasingly serious problem. Cadmium(Cd) is one of the most phytotoxic heavy metal elements and is attracting increasing research attention. It easily enters the food chain and poses considerable threat to human health. Vetiveria zizanioides is a tall (1-2 m), fast-growing,and perennial tussock grass that is eurytopic in terms of habitat choice. It develops a long (3-4 m), massive,and complex root system that can penetrate the deeper layers of the soil. V. zizanioides has a strong tolerance for Cd, and it can adapt to tolerate Cd at low concentrations over a long period, or high Cd concentrations over a short period.The Cd can be absorbed and stored by V. zizanioides while retaining its stability. Healthy and equal-sized plants were chosen, cleared, and cultured for 7 days in complete Hoagland nutrient solution. After the plants had grown buds, they were treated with different gradients of Hoagland's solution modified by adding Cd with cadmium sulfate (1:1) hydrate (3:8) (3CdSO4·8H2O) to create Cd concentrations of 0, 1, 3, 5, and 7 mg/L.The experiments were carried out separately in three different groups. The plants were harvested after 10 days. The whole plant was washed under tap water and rinsed with deionized water. The roots, stems, and leaves were separated, put into a cabinet dryer at 105℃ for 30 min, further dried in a cabinet dryer at 80℃for a another 48 h and finally milled into a fine powder (less than 200-mesh) with a stainless steel attritor. This study deals with the physiological response of the changes in chemical contents in the root, stem, and leaf of V. zizanioides seedlings stressed by excess cadmium ions (Cd2+) using the Fourier transform infrared spectroscopy technique (FTIR). Cadmium(Cd) accumulation in plants and its subcellular distribution (determined by atomic absorption spectroscopy) were tested under the different Cd2+ concentrations to elucidate the mechanism of Cd2+ tolerance and the accumulation characteristics of Cd2+ in V. zizanioides. This result indicates that after an initial decline, absorbance in roots of the dominant infrared band (near 2927 cm-1) exhibited an increase. At low Cd2+ concentrations (<3 mg/L), organic acids secreted by V. zizanioides were able to chelate Cd2+, which leading to a decrease in carboxylic acid O-H. At high Cd2+ concentrations (>3 mg/L), chelating activity decreased, which was followed by an increase in organic acids. After an initial increase, absorbance changes in stems of the dominant infrared band (near 1631 cm-1) exhibited a decline. This indicates that at low Cd2+ concentrations (<3 mg/L), osmosis of organic substances (e.g. amino acids, peptides, and proteins) occurred, improving Cd2+ tolerance.However, with the increase in Cd2+ concentrations, the binding force between peptide bonds and hydrogen bonds in protein secondary structure was significantly affected. In addition, the plant accumulated large amount of Cd2+, up to the maximum of 212.49 mg/kg (shoot) and 290.59 mg/kg dry weight (root) after 10 days when the plant was treated with a Cd2+ concentration of 7 mg/L. The Cd2+ in the shoot (stem and leaf) usually increased with increasing Cd2+ concentrations. Cadmium accumulated in leaves was mainly distributed in the cytoplasm, followed by the cell wall, and was least distributed in the mitochondria and chloroplast. This study demonstrates the potential of the Fourier transform infrared spectroscopy as a non-invasive and rapid technique for monitoring of plants stressed with heavy metals. 参考文献 相似文献 引证文献