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.