College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, People's Republic of China.
Protoplasma. 2021 Mar;258(2):361-370. doi: 10.1007/s00709-020-01568-z. Epub 2020 Oct 26.
As the by-products of edible oil production with rich lignin, the reserves of Camellia oleifera shell were abundant and had a great economic value. Lignin was the most important limiting factor during the conversion of plant biomass to pulp or biofuels, which mainly deposited in the stone cells of C. oleifera shells. Thus, its lignin deposition made the function of stone cells in the ripening process of the shell clearer, and provided a theoretical basis for the potential utilization of the biomass of C. oleifera shells. In this study, the paraffin embedding method was used to investigate the development and difference of stone cell in the fruitlet. The lignin deposition characteristics of stone cell were analyzed by the fluorescence microscopy and Wiesner and Mäule method. The chemical-functional group types of lignin in the stone cell of C. oleifera shell were examined by the ultraviolet spectrophotometer and transform infrared spectroscopy. The stone cells, vessels, parenchyma, and vascular tissue had existed during the young fruit growing period. The anatomical characteristics and the cell tissue ratio inverse relationship between stone cell and parenchymal cell suggested that stone cells developed from parenchymal cells. With the growth of shell, the stone cell wall thickened, and thickness-to-cavity ratio from 0 to 3.6. The fluorescent results showed that lignin content increased continuously; during shell development, the mean brightness of stone cell wall from 0 to 77.9 sections was stained with phloroglucinol-HCl, and Mäule revealed the presence of G-S-lignin in stone cells, and ImageJ results showed that G-lignin was distributed in the entire stone cell wall, while S-lignin deposition accounted for 48.59% of the cell wall area. In the FTIR spectra, the shell was identified as containing G-S-lignin.
油茶叶壳作为食用油生产的副产物，其木质素资源丰富，具有很大的经济价值。木质素是植物生物质转化为纸浆或生物燃料的最主要的限制因素，主要沉积在油茶壳的石细胞中。因此，其木质素的沉积使石细胞在壳成熟过程中的功能更加清晰，为油茶壳生物质的潜在利用提供了理论依据。本研究采用石蜡包埋法研究了幼果中石细胞的发育和差异。利用荧光显微镜和 Wiesner 和 Mäule 法分析了石细胞的木质素沉积特征。利用紫外分光光度计和变换红外光谱仪检测了油茶壳石细胞中木质素的化学官能团类型。在幼果生长期间，石细胞、导管、薄壁组织和维管束就已经存在。石细胞与薄壁组织细胞的解剖特征和细胞组织比例呈反比关系，表明石细胞是由薄壁组织细胞发育而来的。随着壳的生长，石细胞壁逐渐增厚，厚度与腔室的比例从 0 增加到 3.6。荧光结果表明木质素含量不断增加；在壳发育过程中，石细胞壁从 0 到 77.9 节的平均亮度用间苯三酚-HCl 染色，Mäule 显示石细胞中存在 G-S-木质素，ImageJ 结果表明 G-木质素分布在整个石细胞壁中，而 S-木质素沉积占细胞壁面积的 48.59%。在 FTIR 光谱中，壳被鉴定为含有 G-S-木质素。
