6种杜鹃花属(Rhododendron)植物叶片结构的研究

利用光学显微镜和扫描电子显微镜观察了6种杜鹃属植物的叶片结构，结果表明，它们具有共同形态结构特征：典型的异面叶，上表皮由2～3层细胞组成，内大外小或内、外等大，有较厚的角质膜，无气孔器分布；下表皮均由1层细胞组成，排列紧密；栅栏组织由2层以上长柱形细胞组成，排列紧密；海绵组织细胞较短，排列较疏松，细胞间隙较大；均有表皮附属物。但是在各种间也存在结构差异，如叶片的厚度，气孔大小、气孔形态、气孔指数以及分布类型，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，也在分类学上为种问鉴别提供了可靠依据。

STUDY ON THE LEAF BLADE STRUCTURE OF SIX SPECIES OF RHODODENDRON

The leaf epidermis structures of 6 species of Rhododendron had been observed under LM and SEM. The results show that all share together common features as follows: the leaf blades are typical back-abdomen bifacial types, the upper epidermis are formed by two or three layer bigger cells which inside layer cell is bigger than outside one, and the upper epidermis are covered with thicker cuticle. There are many stomas distributed in lower epidermis formed by one layer of small cells, while the upper epidermis have not. The palisade tissue are formed by more than two layer long column cells that line up densely, and cells of the spongy tissue line up loosely and have the bigger cell interval. There are epidermis trichomes. But there are many differences of the structure characteristic of between plants: the thickness of leaf blade, the stoma size, shape, index, the type of the stomatal distributed, the type of epidermis trichome and middle vein bundle, and so on. These structures differences are the characteristic manifestation of the anti-cold and anti- drought, on the other hand, they also provid discriminate characteristic dependable in the taxonomy.