Ferreira Bruno G, Teixeira Cristiane T, Isaias Rosy M S
Universidade Federal de Minas Gerais (UFMG), Instituto de Ciências Biológicas, Departamento de Botânica (BGF, CTT, RMSI) Brasil.
Universidade Federal de Minas Gerais (UFMG), Instituto de Ciências Biológicas, Departamento de Botânica (BGF, CTT, RMSI) Brasil
J Histochem Cytochem. 2014 Aug;62(8):577-83. doi: 10.1369/0022155414538265. Epub 2014 May 14.
Histochemical analyses in plants are commonly performed on hand-made sections of fresh materials. The disadvantages of embedding in historesin, paraffin or paraplast® are the alterations to cellular contents, the high costs and few evident results, depending on the test. Polyethylene-glycol (PEG), as a low cost, hydrophilic medium that maintains most of the cellular features similar to fresh conditions, may be useful for obtaining good histochemical results in thinner and homogeneous sections. The current study aimed to compare the efficiency of PEG as an embedding medium for histochemical analyses of primary and secondary metabolites accumulation. Using hand-made sections of fresh samples (T1) as a comparison, we tested the influence of the use of Karnovsky's solution as a fixative (T2) versus embedding in PEG (T3). The samples herein analyzed comprise leaves, stems, seeds and insect galls of different plant species. Neither the Karnovsky's fixative nor the embedding in PEG altered the histochemical results for starch, lipids, terpenoids, proteins and reducing sugars in T1, T2, and T3. However, PEG binds to phenols, such as tannins, flavonoids and lignins, thereby presenting false negatives in T3.
植物组织化学分析通常在新鲜材料的手工切片上进行。使用组织树脂、石蜡或Paraplast®包埋存在一些缺点，包括细胞内容物的改变、成本高以及根据测试不同结果不明显。聚乙二醇（PEG）作为一种低成本的亲水性介质，能保持大部分细胞特征与新鲜状态相似，可能有助于在更薄且均匀的切片中获得良好的组织化学结果。本研究旨在比较PEG作为包埋介质用于初级和次级代谢产物积累的组织化学分析的效率。以新鲜样品的手工切片（T1）作为对照，我们测试了使用卡诺夫斯基溶液作为固定剂（T2）与用PEG包埋（T3）的影响。本文分析的样品包括不同植物物种的叶片、茎、种子和虫瘿。在T1、T2和T3中，卡诺夫斯基固定剂和PEG包埋均未改变淀粉、脂质、萜类化合物、蛋白质和还原糖的组织化学结果。然而，PEG会与酚类物质结合，如单宁、黄酮类化合物和木质素，从而在T3中呈现假阴性结果。
