Abstract:

To investigate the adaptability mechanism of the anatomical structure of the Rhamnus ussuriensis stems and leaves to the environment， the stems and leaves of Rh. ussuriensisis were studied by paraffin sections and scanning electron microscopy. The results showed that： leaf blade of Rh. ussuriensisis was bifacial； trichomes and stomata were distributed in lower epidermis； stomatal index was 39.04 %； the palisade tissue was composed of two layers of parenchyma cells； the palisade tissue had a compact structure， however， the spongy tissue was loosely arranged. The main veins of the leaves were developed， the vascular bundles were arranged in the ring-shape， the number of xylem vessels and the diameter was large respectively， and the parenchyma cells around the vascular bundle contained abundant ergastic substance. In the primary structure of stem， the cuticle of epidermal cells was thick， and the cells of cortex parenchyma contained crystal clusters. The vascular bundle was open collateral vascular bundle； the medulla was developed； the secondary structure of the stem had obvious annual rings， which was a typical ring-porous wood， with concave lenticels and developed secondary xylem； most of the vessels were spiral vessels and pitted vessels， and the vessel member were mostly compound pores. The rays were mainly single rays， with a small number of double rays. The anatomical structure of the R. ussuriensishas leaves and stems had obvious characteristics of drought resistance and cold resistance， it might adapt to arid and cold environments.

Key words: Rhamnus ussuriensis, leaf, stem, anatomical structure, ecological adaptation