Abstract: We observed the differences in leaf anatomical structure between the male and the female using paraffin method to investigate leaf secondary sex characteristics of Hippophae rhamnoides L.. Results showed that:(1)Both the male and the female leaves consisted of epidermis, mesophyll and veins. The epidermis was composed of a layer of cells with developed trichomes, including similar bulliform cells in upper epidermis; the differentiation of palisade tissue and spongy tissue was obvious in mesophyll. (2)There were more similar bulliform cells in upper epidermis, more ergastic substances in some parenchymal cells of phloem and below the phloem, more trichomes in lower epidermis in the female plant than in the male one; the male plant were significantly higher than the female in leaf thickness, thickness of leaf upper epidermis, thickness of palisade tissue, thickness ratio palisade tissue/sponge tissue, and had more developed vascular bundle than the female in main vein. These results suggested that there were obvious differences in leaf anatomical structure between the female and the male plants of the species, and the differences were the performances of secondary sex characteristics, also robust adaptive strategy formed in the long-term evolution, which might be good for reproduction of the species.

Key words: Hippophae rhamnoides L., dioecism, leaf blade, comparative anatomy