Abstract: The experiment was conducted to study the anatomical characteristics of alpine wild crabapples and their ecological adaptation, the vegetative organ structures of Malus toringoides and Malus transitoria from 3 000 m altitude in western Sichuan Plateau with paraffin sectioning and NaOCl. The two crabapples had similar anatomical structures. The possible reason might be their closed relationships of origins and geographic distribution between them. Both of the two plants had thick cuticle and epidermis cells. There was not stomata on the upper epidermis, while a dense stomata distribution was observed on the lower epidermis. The collateral vascular bundle was rich in palisade tissues on the lower epidermis. The longitudinal ridges structure with palisade and sponge tissues existed in the petiole. The phelloderm cells were crassexinous. The secondary xylem was rather rich in the stem. There were some wood parenchyma cells with lignified cell wall in the vicinity of the vessels. Around the pith there were crassexinous cells, called perimedullary zone. The secondary structure existed in the thin roots of both of the two crabapples, in which there was a large proportion of xylem and no pith. The vessels were dense, in the form of solitary pore. Therefore, the two alpine crabapples adapted well to the dry environment of western Sichuan Plateau.

Key words: western Sichuan Plateau, Malus toringoides, Malus transitoria, anatomical structure, ecological adaptability