榕樹枝條上皮孔的形成

The Formation of Lenticels on The Branches of Ficus microcarpa L. f.

本文研究榕樹枝條上皮孔的形成。榕樹枝條上的皮孔均起源於氣孔下方排列疏鬆的薄壁細胞（前充塞細胞群），此群細胞進行各方向的細胞分裂，而其下緣之細胞則皆行平周分裂即為木栓形成層，其分裂面連成弧形並與一般周皮相連。木栓形成層首先在離心方向產生一至二層排列緊密的封閉層，而後為一至四層排列疏鬆的填充細胞。成熟皮孔呈透鏡形向內、外凸出，其由栓皮層、木栓形成層、和封閉層與填充細層之由外依次交互排列而組成。皮孔內可觀察到多面體草酸鈣結晶和數排的單寧細胞。成熟枝條泡水後皮孔產生腫大的現象，是由排列疏鬆的長桿狀薄壁細胞所組成。

The formation of lenticels on the branches of Ficus microcarpa L. F. was examined. Beneath the stomata of a young branch, the division of precomplementary cells progressed from the cortex inwards and then the lenticel phellogen was formed. It was found to be continuous with the phellogen of periderm. The phellogen of the lenticel centrifugally produced a compact suberized closing layer and then one to four layers of unsuberized complementary cells. The mature lenticels are lens-shaped and convex towards both the exterior and interior. They are centrifugally composed of phylloderm, lenticel phellogen, and several strata of complementary cell layers alternated with a single closing layer. In the lenticel, some prismatic calcium oxalate crystals and several rows of radially arranged tannin cells were observed. Lenticel hypertrophy arose in the immersed mature internodes. It was characterized by large and loosely interconnected thin-walled cells.