Cd对小白菜萌发生理影响的FTIR-ATR研究

应用傅立叶变换-衰减全反射红外光谱（FTIR-ATR）分析方法,用在一定浓度（0.0、0.1、0.5、1.0、5.0mg·kg-1）Cd胁迫下萌发3d的小白菜做试验材料,揭示了小白菜幼芽和幼根中蛋白质、碳水化合物的含量以及蛋白质二级结构对Cd胁迫的不同响应。结果表明,Cd处理导致幼根和幼芽1632cm-1和1030cm-1吸收峰强度显著增强,且1632cm-1峰的波数降低,说明蛋白质、碳水化合物含量增高以及蛋白质二级结构保持稳定,是小白菜种子萌发过程中抵御Cd毒害的重要原因。幼根FTIR谱未出现1710cm-1峰,说明分泌有机酸螯合Cd并非种子萌发初期幼根抗Cd毒机制。幼根中碳水化合物吸收峰强度,随着Cd处理浓度的增加增大,而幼芽中则先减小后增大,说明幼芽（主要为子叶）中的糖类转运至根部,以提高对Cd的耐受性。FTIR谱主要吸收峰强度与生理指标之间的相关性分析结果表明,小白菜幼根FTIR谱中主要吸收峰的强度与根长、超氧化物歧化酶（Superoxide Dismutase,SOD）活性、丙二醛（Malondial dehyde,MDA）含量等指标之间显著相关。以上结果说明FTIR-ATR法可用于植物对Cd胁迫的...

Physiological Response of Brassica chinensis L.Seeds in Germination to Cadmium Toxicity by FTIR-ATR Spectroscopy

A technique based on fourier transform infrared attenuated total reflection （FFIR-ATR）spectrometry was used to study the physiological changes in chemical composition ofBrassica chinensis L. seeds under a wide range of cadmium（Cd） treatments. The results showed that, after 3 d of Cd stress, the absorption bands corresponding to carbohydrates, ester, proteins and protein secondary structure varied differently. The absorption peaks at 1 632 cm-l and 1 030 cm-1 which were significantly higher than that of control group （P〈0.05）, suggesting the pro- teins and carbohydrates content increased.The shift of the band wavenumber from 1 632 cm-1 to 1 626 cm-1 after Cd stress indicats that the plant was able to maintain a higher ordered form of protein under the stress. These were the important reason against the harm of Cd in the process ofBrassica chinensis L. seeds germination.The band of 1 710 cm-1, which related with organic acid, doesn＇t appeared in the FTIR of radicle ,indicated that the chelation of organic acids in exudation wasn＇t the detoxificaton mechanism in the plant radicle. The band height of carbohydrate of radicle increased with the increases of Cd concentration, while decreased in seedling, indicated that carbohydrate could be transported from seedling to radicle and mitigate the toxic effect of Cd. Furthermore, the height of peaks in the spectra of radicle has a corre- lation with the radicle length, Superoxide Dismutase （SOD） activity, Malondialdehyde （MDA） concent. As a results, FTIR-ATR technique could be accepted as rapid and simple way to study the physiologcal mechanism of plant for adapting the stress of Cd.