For the observation of plant material under a light microscope, free-hand sectioning is usually the fastest and most practical procedure. The staining of the obtained cuts is a crucial step and the action mechanism of the dye is variable. Toluidine blue O is a cationic dye whose metachromatic potential for free-hand sections has long been known. Thus, this work aimed at analysing the performance of Toluidine blue O for this type of sectioning with a systematic and comparative approach. The action of Toluidine blue O pH 4.0 was tested for both fresh and previously clarified free-hand sections from leaves of different species of plant. These sections were compared with sections embedded in glycol-methacrylate resin stained with the same dye or submitted to different histochemical tests. The fresh sections obtained by free-hand and stained with Toluidine blue O permitted the accomplishment of histochemical inferences, with the advantage of maintaining the natural colours from the tissues. The previously clarified sections presented the advantage of having a clearer image, allowing a better cellular delimitation. We concluded that Toluidine blue O is very informative for sections of plant material obtained by free-hand, being, therefore, a procedure that is fast, inexpensive and with excellent results.

中文翻译：

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甲苯胺蓝O pH 4.0的利用和徒手获得的植物切片的组织化学推断

对于在光学显微镜下观察植物材料，徒手切片通常是最快和最实用的程序。获得的切口的染色是一个关键步骤，染料的作用机制是可变的。甲苯胺蓝 O 是一种阳离子染料，其对徒手切片的异染潜力早已为人所知。因此，这项工作旨在通过系统和比较的方法分析甲苯胺蓝 O 在此类切片中的性能。甲苯胺蓝 O pH 4.0 的作用对来自不同植物物种的叶子的新鲜和先前澄清的徒手切片进行了测试。将这些切片与用相同染料染色或进行不同组织化学测试的甲基丙烯酸乙二醇酯树脂切片进行比较。徒手获得并用甲苯胺蓝 O 染色的新鲜切片允许完成组织化学推断，其优点是保持组织的自然颜色。先前澄清的部分展示了图像更清晰的优势，允许更好的细胞定界。我们得出的结论是，甲苯胺蓝 O 对于徒手获得的植物材料切片非常有用，因此是一种快速、廉价且效果极佳的程序。