耐寒杜鹃叶片结构研究

Study on the Leaf Structure of Hardy Rhododendron

利用光学显微镜观察辽宁地区耐寒杜鹃(Rhododendron)8种植物的叶片结构,结果表明,它们具有共同的形态结构特征。杜鹃叶为典型的异面叶,上表皮由1～2层细胞组成,内大外小,均无气孔器,有些种具有较厚的角质层;下表皮均由1层小细胞组成,分布有很多气孔器,气孔类型及分布密度因种而异;栅栏组织由1～3层长柱状细胞组成,排列紧密;海绵组织细胞较短,排列较疏松,细胞间隙较大。但是在种间也存在结构差异,如叶片厚度、气孔大小、气孔形态以及分布类型、表皮附属物的类型以及中脉维管束的类型等具有不同的结构特征,这些结构特征差异既是抗寒、抗旱性的表现形式,也在分类学上为种间鉴别提供了可靠依据。

The leaf epidermis structures of hardy Rhododendron in Liaoning were observed under optical microscope.The results showed that they shared the common features as follows：The leaf blades were typical back-abdomen bifacial types, the upper epidermis were formed with one or two layers of bigger cells and the inside layer cell was bigger than the outside one, some upper epidermis were covered with thicker cuticle.There were many stomas distributed in lower epidermis formed with one layer of small cells, while the upper epidermis didn＇t.The stomata type and distribution density varied in species.The palisade tissue was formed with one or three layers of long column cells lined up densely.The cells of the spongy tissue lined up loosely and had the bigger cell interval.But there were many differences in structure characteristics among plants：the thickness of leaf blade, the stoma size, shape, the type of the stomata distributed, the type of epidermis trichome or gland scales and middle vein vascular bundle, and so on.These structure differences could be used in taxonomy distinguish.