气生凤梨叶片结构研究

Foliar Structure of Several Species of Epiphytic Tillandsia(Bromeliaceae)

我们以地生凤梨(Guzmnania‘Denise’)作为对照,利用扫描电镜技术、石蜡切片技术对3种气生凤梨(Til-landsia stricta‘Hard leaf’、T.stricta‘Cotton candy’与T.filifolia)的叶片表面和内部结构进行了研究。结果表明所有凤梨叶片表面均分布着葵花状的鳞片,鳞片由碟状细胞、环状细胞和翼状细胞3类细胞构成,最内部的碟状细胞通过柄状细胞与叶片内部的叶肉细胞相连。气生凤梨叶片表面鳞片白色、蜡质、密度很大,但气孔很少或不可见,暗示鳞片除吸收水分和养分外,还可能具有减少光呼吸、排水及反射阳光等功能。另外,不同的气生凤梨之间叶片表面鳞片的形态、大小和密度也不同,反映了它们对其不同起源地及现生存环境的适应。

We analyzed and compared external and internal structure of the leaves of three epiphytic Tillandsia species（Tillandsia stricta ＇Hard leaf＇,T.stricta ＇Cotton candy＇ and T.filifolia） and one terrestrial species of Bromeliaceae,Guzmania ＇Denise＇,by scanning electron microscope（SEM） and paraffin section.The results showed that the sunflower-shaped trichomes covered the leaf surface in all species studied.The foliar trichomes were made up of disc cells,ring cells and wing cells,and the central disc cells were connected with mesophyll cells by a passage with 2-3 cells.The foliar trichomes of the epiphytic Tillandsia were white and waxy with high densities,but stomata is little or not detectable,which indicated the foliar trichomes would functioned as reduction of transpiration,water repellency and photoprotection other than water and nutrient Absorption.In addition,the foliar trichomes among different epiphytic Tillandsia species were different in density,shape and size,which suggested that different species have been adapted to their ancestral and present environment.