不同成熟度烟叶密集烘烤过程中细胞超微结构的变化

【目的】以红花大金元（简称红大）为材料，探讨不同成熟度处理对密集烘烤过程中烟叶细胞超微结构变化的影响，为红大品种合理成熟采收和烘烤工艺优化提供理论依据。【方法】在密集烤房内进行烟叶烘烤，在电镜下观察不同成熟度处理烟叶在鲜叶采摘及烘烤过程中关键温度点（38℃、42℃、48℃）细胞超微结构的变化。【结果】细胞超微结构观察表明，不同成熟度鲜烟叶在细胞结构上的差异主要表现在叶绿体等细胞器与细胞壁的紧贴程度以及细胞间隙的大小不同，烟叶烘烤过程中叶绿体、细胞核以及相关膜结构变化最为显著，变黄期是烟叶中淀粉和色素类物质降解的主要阶段。在烘烤过程中，与尚熟、过熟相比较，烟叶适熟采收更有利于烟叶中部分糖类物质的转化，使淀粉及色素类物质进一步降解，从而提高烟叶品质。【结论】适熟采收对改善烟叶组织结构及品质具有重要意义。

Changes of Cell Ultrastructure of Flue-Cured Tobacco Leaves with Different Maturities During Bulk Flue-Curing

【Objective】The flue-cured tobacco cv. Honghuadajinyuan (hereafter referred as “HD”) was taken as experimental material to study the changes of cell ultrastructure of tobacco leaves during bulk-curing, which intended to provide a theoretical basis for harvesting maturity and optimization of curing technique of HD. 【Method】Tobacco leaves of different maturities were cured in the bulk flue-curing room, the cell ultrastructures of which were studied respectively at key temperature points (38℃, 42℃, 48℃) during the flue-curing process. 【Result】 Results of cell ultrastructure observation showed that the differences of cell structures of fresh tobacco leaves among various maturity degrees were mainly showed by the extent of chloroplast adhering to cell wall and the size of intercellular space. Chloroplast, nucleus and related membrane structure changed most obviously during the flue-curing process. Moreover, the yellowing process was the key stage for degradation of starch and pigmentary substances in tobacco leaves. Compared with the mature and over-ripe tobacco leaves, those harvested when optimally matured was beneficial to the transformation of carbohydrates and further degradation of starch and pigmentary substances, by which the quality traits of tobacco leaves could also be improved at the same time.【Conclusion】Harvesting at an optimum maturity was quite essential for the improvement of leaf structure and quality.