烟叶烘烤过程中表皮微形态特征的扫描电镜观察初报

Preliminary Report on the Scanning Electron Microscope Observation of Epidermal Micromorphology during Tobacco Flue-curing

【目的】探讨烘烤过程中烤烟烟叶表皮微形态特征的结构变化。【方法】以烤烟品种K326适熟的上部烟叶为材料,采用扫描电镜技术观察烘烤过程中(烘烤前、36℃末期、38℃末期、42℃末期、48℃末期、54℃末期和68℃末期)烟叶下表皮微形态特征。【结果】随着烘烤温度的升高,烤烟叶片气孔器长度从烘烤前的27.46μm减小至68℃末期的22.47μm;气孔器密度从烘烤前的103.76个/mm2增加至68℃末期167.48个/mm2,气孔器逐渐突出于表皮之上,形状从阔椭圆形逐渐变为椭圆形,气孔外拱盖内缘形状从浅波状到深波状;表皮细胞密度从烘烤前的463.24个/mm2增加至68℃末期的895.42个/mm2,垂周壁波纹显著加深,平周壁逐渐凸起;表皮细胞角质层从近于光滑到具条纹甚至具脊状突起;表皮蜡质纹饰从稀疏小颗粒状到大颗粒状甚至为块状。具分泌功能的腺毛顶部细胞形状从完整饱满状到细胞壁明显凹陷,部分从柄细胞处脱落。【结论】烤烟烘烤过程中表皮微型态特征变化显著,这些特征变化可为烤烟烘烤特性的研究提供参考。

[Purpose]To study the structural changes of flue-cured tobacco’s epidermis micromorphological characteristics during curing.[Method]The suitable ripe leaf of flue-cured tobacco‘K326’was used as material,the micromorphological characteristics of the lower epidermis of tobacco leaves during different curing processes(before curing,the end of 36℃,the end of 38℃,the end of 42℃,the end of 48℃,the end of 54℃and the end of 68℃)were observed and compared by scanning electron microscope(SEM).[Result]With the increase of curing temperature,the length of stomata decreased from 27.46μm before curing to 22.47μm at the end of 68℃,the density of stomata increased from 103.76 pieces/mm2 before curing to 167.48 pieces/mm2 at the end of 68℃,and gradually protruded above the epidermis,the shapes varies from broad ellipse to ellipse.The inner margin of outer stomata ledge varies from shallow wave to deep wave;the density of epidermal cells increased from 463.24 pieces/mm2 before curing to 895.42 pieces/mm2 at the end of 68℃,the patterns of anticlinal wall deepens significantly,and the periphery wall gradually protrudes.The cuticle of epidermal cells ranges from nearly smooth to striped or even ridged.The waxy ornamentation of epidermis varies from sparse small granule to large granule or even lump.The shape of the top cells of glandular hair with secretory function changed from full to sunken,and some of them fell off from the stalk cells.[Conclusion]The characteristics of epidermis micropattern changed significantly during flue-cured tobacco curing,and the microstructure features can be used as reference for the curing of flue-cured tobacco.