EDDS处理对硒胁迫下彩叶草根系FTIR-ATR、SEM-EDXS特征及生理特性的影响

Effect of EDDS Treatments on FTIR-ATR,SEM-EDXS Features and Physiological Characteristics of Coleus blumei Roots under Se Stress

为了解乙二胺二琥珀酸(EDDS)诱导植物耐受硒(Se)胁迫的生理机制,以彩叶草(Coleus blumei)为材料,采用营养液培养的方法、借助傅里叶变换-衰减全反射红外光谱(FTIR-ATR)和扫描电子显微镜-X-射线能量色散谱(SEM-EDXS)分析方法及生理指标的变化,研究1.0 mg/L Se胁迫条件下添加0、0.5、1.0、1.5、2.5、5.0 mmol/L EDDS对彩叶草根系化学成分变化的影响。利用FTIR-ATR图谱分析发现,随着EDDS处理浓度的提高,彩叶草根系透射峰所对应峰形基本不变,而参与Se吸附的基团如羟基、酰胺基和指纹区等的透射峰发生了不同程度的位移。FTIR-ATR的特征峰与彩叶草根系响应Se胁迫的各生理指标变化趋势基本一致,且FTIR-ATR比传统的生理指标测定更敏感、便捷。SEM-EDXS扫描还发现随着EDDS处理浓度的升高,根系中K、Mg、Fe、Si等元素的含量升高,而营养元素Ca含量降低。该研究结果可为深入了解EDDS处理下彩叶草对Se胁迫的响应机理提供科学依据。

To understand the physiological mechanism of [S, S＇]-ethylenediamine disuccinic acid （EDDS） inducing plant resistance to selenium （Se）, a hydroponic experiment with different concentrations of EDDS （0, 0.5, 1.0, 1.5, 2.5, and 5.0 mmol/L） was conducted to investigate the chemical component changes in Coleus blumei roots under Se stress （1.0 mg/L） using scanning electron microscopy-X-ray energy dispersive spectroscopy （SEM-EDXS） and Fourier transform infrared spectroscopy-attenuated total reflectance （FTIR- ATR） with physiological trait changes. Results showed that the peak shape of the C. blumei root component remained invariable, as observed by FTIR-ATR spectra. A significant transmission peak shift of some function groups, such as hydroxyl groups, acid amide groups and fingerprint region, was obtained when they participated in the process of absorbing Se. There was good correspondence between the changes in the physiological characteristics and changes in samples based on the indices of wave number absorbance of FTIR-ATR spectra, and FTIR-ATR was more sensitive and convenient. SEM-EDXS analysis showed that the element contents of K, Mg, Fe and Si in the roots increased and the content of Ca decreased with increasing EDDS concentration.