O-4-linked coniferyl and sinapyl aldehydes in lignifying cell walls are the main targets of the Wiesner (phloroglucinol-HCl) reaction
O-4-linked coniferyl and sinapyl aldehydes in lignifying cell walls are the main targets of the Wiesner (phloroglucinol-HCl) reaction
复制标题
DOI：
10.1007/s00709-002-0030-y
复制
发表时间：
2002-01-01
期刊：
影响因子：
2.9
通讯作者：
Barceló, AR
中科院分区：
文献类型：
--
作者：
Pomar, F;Merino, F;Barceló, AR
研究了木质素中芳醛组分的Wiesner法（间苯三酚-盐酸试剂）的性质和特异性。间苯三酚在乙醇-盐酸中与松柏醛、樟脑醛、香兰素和丁香醛反应，生成粉红色颜料（羟基肉桂基醛）或红棕色颜料（羟基苯甲醛）。然而，由这些肉桂醇和醛衍生的松柏醇、新树醇和高度缩合脱氢聚合物在乙醇-盐酸中不能与间苯三酚反应。间苯三酚与羟基肉桂基醛及其脱氢聚合物反应活性的差异可能是由于在后者中，负责染料反应的未取代（α， β -不饱和）肉桂醛官能团由于涉及β碳的侧链交联反应而丢失。傅里叶变换红外光谱和硫代酸解分析表明，木质素中存在4- o连接的羟基肉桂醛端基和4- o连接的4-羟基-3-甲氧基苯甲醛（香兰素）端基。然而，考虑到4- o连接的香兰素在木质化细胞壁中的含量相对较低，其红棕色间苯三酚加合物的消光系数较低，香兰素不太可能在很大程度上促进间苯三酚阳性染色反应。这些结果表明木质化木质部细胞壁的间苯三酚- hcl粉色染色实际上揭示了木质素中含有的4- o -羟基肉桂醛结构。组织化学研究表明，这些醛结构是在木质部细胞壁木质化的早期阶段组装的，如针叶醛。
The nature and specificity of the Wiesner test (phloroglucinol-HCl reagent) for the aromatic aldehyde fraction contained in lignins is studied. Phloroglucinol reacted in ethanol-hydrochloric acid with coniferyl aldehyde, sinapyl aldehyde, vanillin, and syringaldehyde to yield either pink pigments (in the case of hydroxycinnamyl aldehydes) or red-brown pigments (in the case of hydroxybenzaldehydes). However, coniferyl alcohol, sinapyl alcohol, and highly condensed dehydrogenation polymers derived from these cinnamyl alcohols and aldehydes did not react with phloroglucinol in ethanol-hydrochloric acid. The differences in the reactivity of phloroglucinol with hydroxycinnamyl aldehydes and their dehydrogenation polymers may be explained by the fact that, in the latter, the unsubstituted (alpha,beta-unsaturated) cinnamaldehyde functional group, which is responsible for the dye reaction, is lost due to lateral chain cross-linking reactions involving the beta carbon. Fourier transform infrared spectroscopy and thioacidolysis analyses of phloroglucinol-positive lignifying plant cell walls belonging to the plant species Zinnia elegans L., Capsicum annuum var. annuum, Populus alba L., and Pinus halepensis L. demonstrated the presence of 4-O-linked hydroxycinnamyl aldehyde end groups and 4-O-linked 4-hydroxy-3-methoxy-benzaldehyde (vanillin) end groups in lignins. However, given the relatively low abundance of 4-O-linked vanillin in lignifying cell walls and the low extinction coefficient of its red-brown phloroglucinol adduct, it is unlikely that vanillin contributes to a great extent to the phloroglucinol-positive stain reaction. These results suggest that the phloroglucinol-HCl pink stain of lignifying xylem cell walls actually reveals the 4-O-linked hydroxycinnamyl aldehyde structures contained in lignins. Histochemical studies showed that these aldehyde structures are assembled, as in the case of coniferyl aldehyde, during the early stages of xylem cell wall lignification.