An inexpensive and environmentally friendly staining method for semi-permanent slides from plant material probed using anatomical and computational chemistry analyses

Abstract One of the main methods for plant anatomy study is the analysis of thin, transparent, and stained tissue sections. Synthetic dyes traditionally used in anatomical studies might be expensive and produced by specific companies. In contrast, the use of alternative industrial dyes can both represent an inexpensive substitute as well as an environmentally friendly option for conducting plant anatomy studies. In this study, a set of 22 textile dyes was evaluated. Transversal-, longitudinal, and paradermal sections of plant organs obtained using the freehand cutting technique were stained using hydroalcoholic solution (0 to 100%) of textile dyes purchased from a local market. Dyes mixed with 50% hydroalcoholic solution showed higher efficiency in tissue contrast, allowing greater solubility of dye powder and better solution interaction with the plant tissues. Most of the tested dyes showed satisfactory staining results. Cell wall, especially lignified one, showed higher staining efficiency. Computational docking analysis and molecular models of cellulose and lignin showed the probable association mechanisms and dye selectivity to cell wall constituents. Our findings suggest that the developed method can be useful in mixed practical classes of plant anatomy, chemistry, and/or biochemistry, both at high school as well as undergraduate levels.

摘要：植物解剖学研究的主要方法之一，是对薄而通透且经染色处理的植物组织切片开展分析。传统解剖学研究中使用的合成染料往往成本高昂，且仅由特定厂商生产。与之相对，选用替代性工业染料不仅可作为廉价替代方案，同时也是开展植物解剖学研究的环保选择。本研究对22种纺织染料进行了评估：通过徒手切片法（freehand cutting technique）获取植物器官的横切面、纵切面与平周切片（paradermal section），使用本地市场购得的纺织染料配制浓度范围为0~100%的水醇溶液（hydroalcoholic solution）进行染色。实验结果显示，与50%水醇溶液混合的染料在组织对比度提升方面效果更优，不仅可提高染料粉末的溶解度，还能优化溶液与植物组织的相互作用。多数受试染料均取得了令人满意的染色效果，其中细胞壁（尤其是木质化细胞壁）的染色效率更高。通过分子对接分析（computational docking analysis）与纤维素、木质素的分子模型，本研究阐明了染料与细胞壁组分间可能的结合机制及染色选择性。本研究结果表明，所开发的染色方法可应用于高中及本科阶段的植物解剖学、化学及/或生物化学综合实践课程。