Abstract: We analyzed the characters of leaf anatomical structures of Malus sieversii(wild apple trees) in different populations and different growth ages by paraffin sections. The leaf of M.sieversii is bifacial, composed of upper epidermis, palisade mesophyll, spongy mesophyll and lower epidermis. Thickness of tissues and patterns of cell arrangement is not same in different populations, and those in GongLiu, EMin and TuoLi show thickened palisade mesophyll and higher value of P/S ratio. However, the leaves of wild apple trees in XinYuan correlate with thinner palisade mesophyll and lower P/S. Leaf thickness reduces with the increase of age of tree. The perennial and “The King of Wild Apple” are with less layers of palisade and spongy as well as the thinner leaves. Our results imply that M.sieversii can adapt to different environment and growth status to ensure the efficiency of photosynthesis with the coordination of each part of the anatomical structure. Our data provide evidences for in situ preservation and conservation of M.sieversii.

Key words: Malus sieversii, anatomical structure, ecological adaptability