类腐植酸的组分、分子结构及其生理活性研究

采用元素分析、傅立叶变换红外光谱(FT-IR)和固体13C核磁共振等方法，对四种不同原料制备的类腐植酸与矿物源腐植酸在组分、元素组成和分子结构方面进行了研究，通过种子萌发实验对类腐植酸的生理活性进行了测定。结果表明，以草本植物(麦草、竹子)为原料制备的类腐植酸中，黄腐酸的含量明显高于木本植物(松木、杨木)制备的样品。类腐植酸与矿物源腐植酸的分子结构相似，具有腐植酸的特征官能团。与矿物源腐植酸相比，类腐植酸结构更复杂，其中芳香族结构、木质素衍生物及多糖等结构含量更多，含氧官能团含量较低，其中草本植物源制备的类腐植酸比木本植物制备的样品的芳香化程度更高，分子量更小。小麦种子萌发研究结果显示，类腐植酸浓度为20~40 mg/L时对种子萌发起到明显的促进作用，但浓度过高反而会抑制其生长。

Study on humic acid-like components,molecular structure and physiological activity

By means of methods of elemental analysis, FT-IR and solid 13C NMR, a comparative study on the component, elemental composition and molecular structure of humic acid-like substances prepared from four different raw materials and humic acids from mineral sources were carried out. Also the physiological activity of four humic acid-like substances was determined by seed germination experiment. The study results showed that the content of fulvic acid in the humic acid-like materials prepared from herbaceous plants (wheat straw and bamboo) was significantly higher than that from woody plants (pine and poplar). The molecular structure of humic acid-like materials was similar to that of mineral humic acid, because both of them had the characteristic functional groups of humic acid. Compared with mineral humic acids, the structures of humic acid-like materials were more complex, and the types and contents of functional groups were different. They have more aromatic structures and lower oxygen-containing functional groups. Also, humic acid-like materials from herbaceous plants had higher aromatization degree and lower molecular weight than those from woody plants. The results of wheat seed germination experiment showed that, when the concentration of the humic acid-like materials was 20~40 mg/L, it can obviously promote the germination of seeds. However the seed growth will be inhibited if the concentration was too high.