傅里叶变换红外光谱法分析香附子对铅胁迫生理响应及其铅积累特性

Physiological Response of Cyperus rotundus to Lead Stress by FTIR Spectroscopy and Its Pb Accumulation

采用傅里叶变换红外光谱法(FTIR)研究了不同铅浓度下(0、50、100、400、800、1500、2500 mg/L)香附子根、茎和叶的化学组成变化,同时测定铅积累特性。结果表明:根组织在2924和3410 cm-1处吸光度先升后降,反映氨基酸和糖类等有机物在低浓度Pb2+处理时常作为渗透性调节物质出现,随着Pb2+含量增大至耐铅性,其合成和运输被抑制,有机物含量下降。此外,根组织在1381 cm-1处吸光度先升后降,可能与香附子在细胞壁上增加抗逆性有关,即低浓度Pb2+处理下细胞壁可通过提高阳离子交换能力增强耐铅性;茎组织在1056、1381、1635、2924、3410 cm-1等处吸光度变化不明显,表明有耐铅性;叶组织在1635 cm-1处的显著特征峰可能与叶中氨基酸、蛋白质和多肽类物质含量升高有关;香附子根、茎、叶在1064 cm-1附近吸光度的变化,表现膜脂过氧化,与其耐铅性有关。另外,香附子根和地上部分的铅含量随Pb2+浓度的增加而增大,地上部分对铅的积累量小于地下部分,说明根部只有部分转移到地上,有效保护了地上组织。

The method of Fourier trasform infraredspoctrometry （FTIR） was used to investigate the physiological changes of chemical compo- sition of Cyperus rotundus during the nutrient solutions supplemented with different concentrations of Pb^2＋ （0, 50, 100, 400, 800, 1500, 2500 mg/L）, and its Pb accumulations were determined. The result showed that the absorption bands of root tissues at 2924 and 3410 cm^-1 increased firstly and then decreased along with the increase of Pb^2 ＋ concentration, indicating organic substances usually served as the osmotic contents under low concentration. Upon the lead tolerance, the synthesis and transportation of organic substances could be restrained and de- creased gradually. Besides, the absorption band of root tissues at 1381 cm^-1 also increased firstly and then decreased, representing that the cell wall improved lead resistance by in^ing action-exchange capacity. The absorption bands of stem tissues at 1056, 1381, 1635, 2924 and 3410 cm-thad no obvious changes, indicating the presence of lead tolerance. The presence of the absorbance of leaf tissue at 1635 cm^-1 might be related to the enhancement of amino acid, protein and polypeptide in Cyperus rotunda. The changes of absorption bands of root, stem and leaf at 1064 cm^-1 suggestedthat the ex-oxidation of membrane lipid increased. In addition, the lead contents in root and a- bove-sreund of Cyperus rotundus usually enhanced with the incrcaseofleadconcentrations. The above-ground enrichment of lead was less than that of underground, which implied that lead in root only tnmsformod partly to above-gronnd, and so it might protect the above-ground tissues effectively.